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10 <title>core - Apache HTTP Server Version 2.5</title>
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20 <p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/quickreference.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p>
21 <p class="apache">Apache HTTP Server Version 2.5</p>
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25 <a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.5</a> > <a href="./">Modules</a></div>
26 <div id="page-content">
27 <div id="preamble"><h1>Apache Core Features</h1>
29 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
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36 <table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Core Apache HTTP Server features that are always
38 <tr><th><a href="module-dict.html#Status">Status:</a></th><td>Core</td></tr></table>
40 <div id="quickview"><h3 class="directives">Directives</h3>
42 <li><img alt="" src="../images/down.gif" /> <a href="#acceptfilter">AcceptFilter</a></li>
43 <li><img alt="" src="../images/down.gif" /> <a href="#acceptpathinfo">AcceptPathInfo</a></li>
44 <li><img alt="" src="../images/down.gif" /> <a href="#accessfilename">AccessFileName</a></li>
45 <li><img alt="" src="../images/down.gif" /> <a href="#adddefaultcharset">AddDefaultCharset</a></li>
46 <li><img alt="" src="../images/down.gif" /> <a href="#allowencodedslashes">AllowEncodedSlashes</a></li>
47 <li><img alt="" src="../images/down.gif" /> <a href="#allowoverride">AllowOverride</a></li>
48 <li><img alt="" src="../images/down.gif" /> <a href="#allowoverridelist">AllowOverrideList</a></li>
49 <li><img alt="" src="../images/down.gif" /> <a href="#asyncfilter">AsyncFilter</a></li>
50 <li><img alt="" src="../images/down.gif" /> <a href="#cgimapextension">CGIMapExtension</a></li>
51 <li><img alt="" src="../images/down.gif" /> <a href="#cgipassauth">CGIPassAuth</a></li>
52 <li><img alt="" src="../images/down.gif" /> <a href="#cgivar">CGIVar</a></li>
53 <li><img alt="" src="../images/down.gif" /> <a href="#contentdigest">ContentDigest</a></li>
54 <li><img alt="" src="../images/down.gif" /> <a href="#defaultruntimedir">DefaultRuntimeDir</a></li>
55 <li><img alt="" src="../images/down.gif" /> <a href="#defaulttype">DefaultType</a></li>
56 <li><img alt="" src="../images/down.gif" /> <a href="#define">Define</a></li>
57 <li><img alt="" src="../images/down.gif" /> <a href="#directory"><Directory></a></li>
58 <li><img alt="" src="../images/down.gif" /> <a href="#directorymatch"><DirectoryMatch></a></li>
59 <li><img alt="" src="../images/down.gif" /> <a href="#documentroot">DocumentRoot</a></li>
60 <li><img alt="" src="../images/down.gif" /> <a href="#else"><Else></a></li>
61 <li><img alt="" src="../images/down.gif" /> <a href="#elseif"><ElseIf></a></li>
62 <li><img alt="" src="../images/down.gif" /> <a href="#enablemmap">EnableMMAP</a></li>
63 <li><img alt="" src="../images/down.gif" /> <a href="#enablesendfile">EnableSendfile</a></li>
64 <li><img alt="" src="../images/down.gif" /> <a href="#error">Error</a></li>
65 <li><img alt="" src="../images/down.gif" /> <a href="#errordocument">ErrorDocument</a></li>
66 <li><img alt="" src="../images/down.gif" /> <a href="#errorlog">ErrorLog</a></li>
67 <li><img alt="" src="../images/down.gif" /> <a href="#errorlogformat">ErrorLogFormat</a></li>
68 <li><img alt="" src="../images/down.gif" /> <a href="#extendedstatus">ExtendedStatus</a></li>
69 <li><img alt="" src="../images/down.gif" /> <a href="#fileetag">FileETag</a></li>
70 <li><img alt="" src="../images/down.gif" /> <a href="#files"><Files></a></li>
71 <li><img alt="" src="../images/down.gif" /> <a href="#filesmatch"><FilesMatch></a></li>
72 <li><img alt="" src="../images/down.gif" /> <a href="#forcetype">ForceType</a></li>
73 <li><img alt="" src="../images/down.gif" /> <a href="#gprofdir">GprofDir</a></li>
74 <li><img alt="" src="../images/down.gif" /> <a href="#hostnamelookups">HostnameLookups</a></li>
75 <li><img alt="" src="../images/down.gif" /> <a href="#httpprotocoloptions">HttpProtocolOptions</a></li>
76 <li><img alt="" src="../images/down.gif" /> <a href="#if"><If></a></li>
77 <li><img alt="" src="../images/down.gif" /> <a href="#ifdefine"><IfDefine></a></li>
78 <li><img alt="" src="../images/down.gif" /> <a href="#ifdirective"><IfDirective></a></li>
79 <li><img alt="" src="../images/down.gif" /> <a href="#iffile"><IfFile></a></li>
80 <li><img alt="" src="../images/down.gif" /> <a href="#ifmodule"><IfModule></a></li>
81 <li><img alt="" src="../images/down.gif" /> <a href="#ifsection"><IfSection></a></li>
82 <li><img alt="" src="../images/down.gif" /> <a href="#include">Include</a></li>
83 <li><img alt="" src="../images/down.gif" /> <a href="#includeoptional">IncludeOptional</a></li>
84 <li><img alt="" src="../images/down.gif" /> <a href="#keepalive">KeepAlive</a></li>
85 <li><img alt="" src="../images/down.gif" /> <a href="#keepalivetimeout">KeepAliveTimeout</a></li>
86 <li><img alt="" src="../images/down.gif" /> <a href="#limit"><Limit></a></li>
87 <li><img alt="" src="../images/down.gif" /> <a href="#limitexcept"><LimitExcept></a></li>
88 <li><img alt="" src="../images/down.gif" /> <a href="#limitinternalrecursion">LimitInternalRecursion</a></li>
89 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestbody">LimitRequestBody</a></li>
90 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfields">LimitRequestFields</a></li>
91 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfieldsize">LimitRequestFieldSize</a></li>
92 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestline">LimitRequestLine</a></li>
93 <li><img alt="" src="../images/down.gif" /> <a href="#limitxmlrequestbody">LimitXMLRequestBody</a></li>
94 <li><img alt="" src="../images/down.gif" /> <a href="#location"><Location></a></li>
95 <li><img alt="" src="../images/down.gif" /> <a href="#locationmatch"><LocationMatch></a></li>
96 <li><img alt="" src="../images/down.gif" /> <a href="#loglevel">LogLevel</a></li>
97 <li><img alt="" src="../images/down.gif" /> <a href="#logleveloverride">LogLevelOverride</a></li>
98 <li><img alt="" src="../images/down.gif" /> <a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></li>
99 <li><img alt="" src="../images/down.gif" /> <a href="#maxrangeoverlaps">MaxRangeOverlaps</a></li>
100 <li><img alt="" src="../images/down.gif" /> <a href="#maxrangereversals">MaxRangeReversals</a></li>
101 <li><img alt="" src="../images/down.gif" /> <a href="#maxranges">MaxRanges</a></li>
102 <li><img alt="" src="../images/down.gif" /> <a href="#mergetrailers">MergeTrailers</a></li>
103 <li><img alt="" src="../images/down.gif" /> <a href="#mutex">Mutex</a></li>
104 <li><img alt="" src="../images/down.gif" /> <a href="#namevirtualhost">NameVirtualHost</a></li>
105 <li><img alt="" src="../images/down.gif" /> <a href="#options">Options</a></li>
106 <li><img alt="" src="../images/down.gif" /> <a href="#protocol">Protocol</a></li>
107 <li><img alt="" src="../images/down.gif" /> <a href="#protocols">Protocols</a></li>
108 <li><img alt="" src="../images/down.gif" /> <a href="#protocolshonororder">ProtocolsHonorOrder</a></li>
109 <li><img alt="" src="../images/down.gif" /> <a href="#qualifyredirecturl">QualifyRedirectURL</a></li>
110 <li><img alt="" src="../images/down.gif" /> <a href="#registerhttpmethod">RegisterHttpMethod</a></li>
111 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitcpu">RLimitCPU</a></li>
112 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitmem">RLimitMEM</a></li>
113 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitnproc">RLimitNPROC</a></li>
114 <li><img alt="" src="../images/down.gif" /> <a href="#scriptinterpretersource">ScriptInterpreterSource</a></li>
115 <li><img alt="" src="../images/down.gif" /> <a href="#seerequesttail">SeeRequestTail</a></li>
116 <li><img alt="" src="../images/down.gif" /> <a href="#serveradmin">ServerAdmin</a></li>
117 <li><img alt="" src="../images/down.gif" /> <a href="#serveralias">ServerAlias</a></li>
118 <li><img alt="" src="../images/down.gif" /> <a href="#servername">ServerName</a></li>
119 <li><img alt="" src="../images/down.gif" /> <a href="#serverpath">ServerPath</a></li>
120 <li><img alt="" src="../images/down.gif" /> <a href="#serverroot">ServerRoot</a></li>
121 <li><img alt="" src="../images/down.gif" /> <a href="#serversignature">ServerSignature</a></li>
122 <li><img alt="" src="../images/down.gif" /> <a href="#servertokens">ServerTokens</a></li>
123 <li><img alt="" src="../images/down.gif" /> <a href="#sethandler">SetHandler</a></li>
124 <li><img alt="" src="../images/down.gif" /> <a href="#setinputfilter">SetInputFilter</a></li>
125 <li><img alt="" src="../images/down.gif" /> <a href="#setoutputfilter">SetOutputFilter</a></li>
126 <li><img alt="" src="../images/down.gif" /> <a href="#timeout">TimeOut</a></li>
127 <li><img alt="" src="../images/down.gif" /> <a href="#traceenable">TraceEnable</a></li>
128 <li><img alt="" src="../images/down.gif" /> <a href="#undefine">UnDefine</a></li>
129 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalname">UseCanonicalName</a></li>
130 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></li>
131 <li><img alt="" src="../images/down.gif" /> <a href="#virtualhost"><VirtualHost></a></li>
132 <li><img alt="" src="../images/down.gif" /> <a href="#warning">Warning</a></li>
134 <h3>Bugfix checklist</h3><ul class="seealso"><li><a href="https://www.apache.org/dist/httpd/CHANGES_2.4">httpd changelog</a></li><li><a href="https://bz.apache.org/bugzilla/buglist.cgi?bug_status=__open__&list_id=144532&product=Apache%20httpd-2&query_format=specific&order=changeddate%20DESC%2Cpriority%2Cbug_severity&component=core">Known issues</a></li><li><a href="https://bz.apache.org/bugzilla/enter_bug.cgi?product=Apache%20httpd-2&component=core">Report a bug</a></li></ul><h3>See also</h3>
136 <li><a href="#comments_section">Comments</a></li></ul></div>
138 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
139 <div class="directive-section"><h2><a name="AcceptFilter" id="AcceptFilter">AcceptFilter</a> <a name="acceptfilter" id="acceptfilter">Directive</a></h2>
140 <table class="directive">
141 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures optimizations for a Protocol's Listener Sockets</td></tr>
142 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptFilter <var>protocol</var> <var>accept_filter</var></code></td></tr>
143 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
144 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
145 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
147 <p>This directive enables operating system specific optimizations for a
148 listening socket by the <code class="directive">Protocol</code> type.
149 The basic premise is for the kernel to not send a socket to the server
150 process until either data is received or an entire HTTP Request is buffered.
151 Only <a href="http://www.freebsd.org/cgi/man.cgi?query=accept_filter&sektion=9">
152 FreeBSD's Accept Filters</a>, Linux's more primitive
153 <code>TCP_DEFER_ACCEPT</code>, and Windows' optimized AcceptEx()
154 are currently supported.</p>
156 <p>Using <code>none</code> for an argument will disable any accept filters
157 for that protocol. This is useful for protocols that require a server
158 send data first, such as <code>ftp:</code> or <code>nntp</code>:</p>
159 <pre class="prettyprint lang-config">AcceptFilter nntp none</pre>
162 <p>The default protocol names are <code>https</code> for port 443
163 and <code>http</code> for all other ports. To specify that another
164 protocol is being used with a listening port, add the <var>protocol</var>
165 argument to the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>
168 <p>The default values on FreeBSD are:</p>
169 <pre class="prettyprint lang-config">AcceptFilter http httpready
170 AcceptFilter https dataready</pre>
173 <p>The <code>httpready</code> accept filter buffers entire HTTP requests at
174 the kernel level. Once an entire request is received, the kernel then
175 sends it to the server. See the
176 <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_http&sektion=9">
177 accf_http(9)</a> man page for more details. Since HTTPS requests are
178 encrypted, only the <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_data&sektion=9">
179 accf_data(9)</a> filter is used.</p>
181 <p>The default values on Linux are:</p>
182 <pre class="prettyprint lang-config">AcceptFilter http data
183 AcceptFilter https data</pre>
186 <p>Linux's <code>TCP_DEFER_ACCEPT</code> does not support buffering http
187 requests. Any value besides <code>none</code> will enable
188 <code>TCP_DEFER_ACCEPT</code> on that listener. For more details
190 <a href="http://man7.org/linux/man-pages/man7/tcp.7.html">
191 tcp(7)</a> man page.</p>
193 <p>The default values on Windows are:</p>
194 <pre class="prettyprint lang-config">AcceptFilter http connect
195 AcceptFilter https connect</pre>
198 <p>Window's mpm_winnt interprets the AcceptFilter to toggle the AcceptEx()
199 API, and does not support http protocol buffering. <code>connect</code>
200 will use the AcceptEx() API, also retrieve the network endpoint
201 addresses, but like <code>none</code> the <code>connect</code> option
202 does not wait for the initial data transmission.</p>
204 <p>On Windows, <code>none</code> uses accept() rather than AcceptEx()
205 and will not recycle sockets between connections. This is useful for
206 network adapters with broken driver support, as well as some virtual
207 network providers such as vpn drivers, or spam, virus or spyware
210 <div class="warning">
211 <h3>The <code>data</code> AcceptFilter (Windows)</h3>
213 <p>For versions 2.4.23 and prior, the Windows <code>data</code> accept
214 filter waited until data had been transmitted and the initial data
215 buffer and network endpoint addresses had been retrieved from the
216 single AcceptEx() invocation. This implementation was subject to a
217 denial of service attack and has been disabled.</p>
219 <p>Current releases of httpd default to the <code>connect</code> filter
220 on Windows, and will fall back to <code>connect</code> if
221 <code>data</code> is specified. Users of prior releases are encouraged
222 to add an explicit setting of <code>connect</code> for their
223 AcceptFilter, as shown above.</p>
229 <li><code class="directive"><a href="#protocol">Protocol</a></code></li>
232 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
233 <div class="directive-section"><h2><a name="AcceptPathInfo" id="AcceptPathInfo">AcceptPathInfo</a> <a name="acceptpathinfo" id="acceptpathinfo">Directive</a></h2>
234 <table class="directive">
235 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Resources accept trailing pathname information</td></tr>
236 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptPathInfo On|Off|Default</code></td></tr>
237 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AcceptPathInfo Default</code></td></tr>
238 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
239 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
240 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
241 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
244 <p>This directive controls whether requests that contain trailing
245 pathname information that follows an actual filename (or
246 non-existent file in an existing directory) will be accepted or
247 rejected. The trailing pathname information can be made
248 available to scripts in the <code>PATH_INFO</code> environment
251 <p>For example, assume the location <code>/test/</code> points to
252 a directory that contains only the single file
253 <code>here.html</code>. Then requests for
254 <code>/test/here.html/more</code> and
255 <code>/test/nothere.html/more</code> both collect
256 <code>/more</code> as <code>PATH_INFO</code>.</p>
258 <p>The three possible arguments for the
259 <code class="directive">AcceptPathInfo</code> directive are:</p>
261 <dt><code>Off</code></dt><dd>A request will only be accepted if it
262 maps to a literal path that exists. Therefore a request with
263 trailing pathname information after the true filename such as
264 <code>/test/here.html/more</code> in the above example will return
265 a 404 NOT FOUND error.</dd>
267 <dt><code>On</code></dt><dd>A request will be accepted if a
268 leading path component maps to a file that exists. The above
269 example <code>/test/here.html/more</code> will be accepted if
270 <code>/test/here.html</code> maps to a valid file.</dd>
272 <dt><code>Default</code></dt><dd>The treatment of requests with
273 trailing pathname information is determined by the <a href="../handler.html">handler</a> responsible for the request.
274 The core handler for normal files defaults to rejecting
275 <code>PATH_INFO</code> requests. Handlers that serve scripts, such as <a href="mod_cgi.html">cgi-script</a> and <a href="mod_isapi.html">isapi-handler</a>, generally accept
276 <code>PATH_INFO</code> by default.</dd>
279 <p>The primary purpose of the <code>AcceptPathInfo</code>
280 directive is to allow you to override the handler's choice of
281 accepting or rejecting <code>PATH_INFO</code>. This override is required,
282 for example, when you use a <a href="../filter.html">filter</a>, such
283 as <a href="mod_include.html">INCLUDES</a>, to generate content
284 based on <code>PATH_INFO</code>. The core handler would usually reject
285 the request, so you can use the following configuration to enable
288 <pre class="prettyprint lang-config"><Files "mypaths.shtml">
290 SetOutputFilter INCLUDES
297 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
298 <div class="directive-section"><h2><a name="AccessFileName" id="AccessFileName">AccessFileName</a> <a name="accessfilename" id="accessfilename">Directive</a></h2>
299 <table class="directive">
300 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Name of the distributed configuration file</td></tr>
301 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AccessFileName <var>filename</var> [<var>filename</var>] ...</code></td></tr>
302 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AccessFileName .htaccess</code></td></tr>
303 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
304 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
305 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
307 <p>While processing a request, the server looks for
308 the first existing configuration file from this list of names in
309 every directory of the path to the document, if distributed
310 configuration files are <a href="#allowoverride">enabled for that
311 directory</a>. For example:</p>
313 <pre class="prettyprint lang-config">AccessFileName .acl</pre>
316 <p>Before returning the document
317 <code>/usr/local/web/index.html</code>, the server will read
318 <code>/.acl</code>, <code>/usr/.acl</code>,
319 <code>/usr/local/.acl</code> and <code>/usr/local/web/.acl</code>
320 for directives unless they have been disabled with:</p>
322 <pre class="prettyprint lang-config"><Directory "/">
324 </Directory></pre>
329 <li><code class="directive"><a href="#allowoverride">AllowOverride</a></code></li>
330 <li><a href="../configuring.html">Configuration Files</a></li>
331 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
334 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
335 <div class="directive-section"><h2><a name="AddDefaultCharset" id="AddDefaultCharset">AddDefaultCharset</a> <a name="adddefaultcharset" id="adddefaultcharset">Directive</a></h2>
336 <table class="directive">
337 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Default charset parameter to be added when a response
338 content-type is <code>text/plain</code> or <code>text/html</code></td></tr>
339 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AddDefaultCharset On|Off|<var>charset</var></code></td></tr>
340 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AddDefaultCharset Off</code></td></tr>
341 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
342 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
343 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
344 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
346 <p>This directive specifies a default value for the media type
347 charset parameter (the name of a character encoding) to be added
348 to a response if and only if the response's content-type is either
349 <code>text/plain</code> or <code>text/html</code>. This should override
350 any charset specified in the body of the response via a <code>META</code>
351 element, though the exact behavior is often dependent on the user's client
352 configuration. A setting of <code>AddDefaultCharset Off</code>
353 disables this functionality. <code>AddDefaultCharset On</code> enables
354 a default charset of <code>iso-8859-1</code>. Any other value is assumed
355 to be the <var>charset</var> to be used, which should be one of the
356 <a href="http://www.iana.org/assignments/character-sets">IANA registered
357 charset values</a> for use in Internet media types (MIME types).
360 <pre class="prettyprint lang-config">AddDefaultCharset utf-8</pre>
363 <p><code class="directive">AddDefaultCharset</code> should only be used when all
364 of the text resources to which it applies are known to be in that
365 character encoding and it is too inconvenient to label their charset
366 individually. One such example is to add the charset parameter
367 to resources containing generated content, such as legacy CGI
368 scripts, that might be vulnerable to cross-site scripting attacks
369 due to user-provided data being included in the output. Note, however,
370 that a better solution is to just fix (or delete) those scripts, since
371 setting a default charset does not protect users that have enabled
372 the "auto-detect character encoding" feature on their browser.</p>
376 <li><code class="directive"><a href="../mod/mod_mime.html#addcharset">AddCharset</a></code></li>
379 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
380 <div class="directive-section"><h2><a name="AllowEncodedSlashes" id="AllowEncodedSlashes">AllowEncodedSlashes</a> <a name="allowencodedslashes" id="allowencodedslashes">Directive</a></h2>
381 <table class="directive">
382 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines whether encoded path separators in URLs are allowed to
383 be passed through</td></tr>
384 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowEncodedSlashes On|Off|NoDecode</code></td></tr>
385 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowEncodedSlashes Off</code></td></tr>
386 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
387 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
388 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
389 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>
390 NoDecode option available in 2.3.12 and later.</td></tr>
392 <p>The <code class="directive">AllowEncodedSlashes</code> directive allows URLs
393 which contain encoded path separators (<code>%2F</code> for <code>/</code>
394 and additionally <code>%5C</code> for <code>\</code> on accordant systems)
395 to be used in the path info.</p>
397 <p>With the default value, <code>Off</code>, such URLs are refused
398 with a 404 (Not found) error.</p>
400 <p>With the value <code>On</code>, such URLs are accepted, and encoded
401 slashes are decoded like all other encoded characters.</p>
403 <p>With the value <code>NoDecode</code>, such URLs are accepted, but
404 encoded slashes are not decoded but left in their encoded state.</p>
406 <p>Turning <code class="directive">AllowEncodedSlashes</code> <code>On</code> is
407 mostly useful when used in conjunction with <code>PATH_INFO</code>.</p>
409 <div class="note"><h3>Note</h3>
410 <p>If encoded slashes are needed in path info, use of <code>NoDecode</code> is
411 strongly recommended as a security measure. Allowing slashes
412 to be decoded could potentially allow unsafe paths.</p>
417 <li><code class="directive"><a href="#acceptpathinfo">AcceptPathInfo</a></code></li>
420 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
421 <div class="directive-section"><h2><a name="AllowOverride" id="AllowOverride">AllowOverride</a> <a name="allowoverride" id="allowoverride">Directive</a></h2>
422 <table class="directive">
423 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Types of directives that are allowed in
424 <code>.htaccess</code> files</td></tr>
425 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowOverride All|None|<var>directive-type</var>
426 [<var>directive-type</var>] ...</code></td></tr>
427 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowOverride None (2.3.9 and later), AllowOverride All (2.3.8 and earlier)</code></td></tr>
428 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
429 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
430 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
432 <p>When the server finds an <code>.htaccess</code> file (as
433 specified by <code class="directive"><a href="#accessfilename">AccessFileName</a></code>),
434 it needs to know which directives declared in that file can override
435 earlier configuration directives.</p>
437 <div class="note"><h3>Only available in <Directory> sections</h3>
438 <code class="directive">AllowOverride</code> is valid only in
439 <code class="directive"><a href="#directory"><Directory></a></code>
440 sections specified without regular expressions, not in <code class="directive"><a href="#location"><Location></a></code>, <code class="directive"><a href="#directorymatch"><DirectoryMatch></a></code> or
441 <code class="directive"><a href="#files"><Files></a></code> sections.
444 <p>When this directive is set to <code>None</code> and <code class="directive"><a href="#allowoverridelist">AllowOverrideList</a></code> is set to
445 <code>None</code>, <a href="#accessfilename">.htaccess</a> files are
446 completely ignored. In this case, the server will not even attempt
447 to read <code>.htaccess</code> files in the filesystem.</p>
449 <p>When this directive is set to <code>All</code>, then any
450 directive which has the .htaccess <a href="directive-dict.html#Context">Context</a> is allowed in
451 <code>.htaccess</code> files.</p>
453 <p>The <var>directive-type</var> can be one of the following
454 groupings of directives. (See the <a href="overrides.html">override class
455 index</a> for an up-to-date listing of which directives are enabled by each
456 <var>directive-type</var>.)</p>
459 <dt><a href="overrides.html#override-authconfig">AuthConfig</a></dt>
463 Allow use of the authorization directives (<code class="directive"><a href="../mod/mod_authz_dbm.html#authdbmgroupfile">AuthDBMGroupFile</a></code>,
464 <code class="directive"><a href="../mod/mod_authn_dbm.html#authdbmuserfile">AuthDBMUserFile</a></code>,
465 <code class="directive"><a href="../mod/mod_authz_groupfile.html#authgroupfile">AuthGroupFile</a></code>,
466 <code class="directive"><a href="../mod/mod_authn_core.html#authname">AuthName</a></code>,
467 <code class="directive"><a href="../mod/mod_authn_core.html#authtype">AuthType</a></code>, <code class="directive"><a href="../mod/mod_authn_file.html#authuserfile">AuthUserFile</a></code>, <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code>, <em>etc.</em>).</dd>
469 <dt><a href="overrides.html#override-fileinfo">FileInfo</a></dt>
472 Allow use of the directives controlling document types
473 (<code class="directive"><a href="#errordocument">ErrorDocument</a></code>,
474 <code class="directive"><a href="#forcetype">ForceType</a></code>,
475 <code class="directive"><a href="../mod/mod_negotiation.html#languagepriority">LanguagePriority</a></code>,
476 <code class="directive"><a href="#sethandler">SetHandler</a></code>,
477 <code class="directive"><a href="#setinputfilter">SetInputFilter</a></code>,
478 <code class="directive"><a href="#setoutputfilter">SetOutputFilter</a></code>, and
479 <code class="module"><a href="../mod/mod_mime.html">mod_mime</a></code> Add* and Remove* directives),
480 document meta data (<code class="directive"><a href="../mod/mod_headers.html#header">Header</a></code>, <code class="directive"><a href="../mod/mod_headers.html#requestheader">RequestHeader</a></code>, <code class="directive"><a href="../mod/mod_setenvif.html#setenvif">SetEnvIf</a></code>, <code class="directive"><a href="../mod/mod_setenvif.html#setenvifnocase">SetEnvIfNoCase</a></code>, <code class="directive"><a href="../mod/mod_setenvif.html#browsermatch">BrowserMatch</a></code>, <code class="directive"><a href="../mod/mod_usertrack.html#cookieexpires">CookieExpires</a></code>, <code class="directive"><a href="../mod/mod_usertrack.html#cookiedomain">CookieDomain</a></code>, <code class="directive"><a href="../mod/mod_usertrack.html#cookiestyle">CookieStyle</a></code>, <code class="directive"><a href="../mod/mod_usertrack.html#cookietracking">CookieTracking</a></code>, <code class="directive"><a href="../mod/mod_usertrack.html#cookiename">CookieName</a></code>),
481 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> directives (<code class="directive"><a href="../mod/mod_rewrite.html#rewriteengine">RewriteEngine</a></code>, <code class="directive"><a href="../mod/mod_rewrite.html#rewriteoptions">RewriteOptions</a></code>, <code class="directive"><a href="../mod/mod_rewrite.html#rewritebase">RewriteBase</a></code>, <code class="directive"><a href="../mod/mod_rewrite.html#rewritecond">RewriteCond</a></code>, <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code>),
482 <code class="module"><a href="../mod/mod_alias.html">mod_alias</a></code> directives (<code class="directive"><a href="../mod/mod_alias.html#redirect">Redirect</a></code>, <code class="directive"><a href="../mod/mod_alias.html#redirecttemp">RedirectTemp</a></code>, <code class="directive"><a href="../mod/mod_alias.html#redirectpermanent">RedirectPermanent</a></code>, <code class="directive"><a href="../mod/mod_alias.html#redirectmatch">RedirectMatch</a></code>), and
483 <code class="directive"><a href="../mod/mod_actions.html#action">Action</a></code> from
484 <code class="module"><a href="../mod/mod_actions.html">mod_actions</a></code>.
487 <dt><a href="overrides.html#override-indexes">Indexes</a></dt>
490 Allow use of the directives controlling directory indexing
491 (<code class="directive"><a href="../mod/mod_autoindex.html#adddescription">AddDescription</a></code>,
492 <code class="directive"><a href="../mod/mod_autoindex.html#addicon">AddIcon</a></code>, <code class="directive"><a href="../mod/mod_autoindex.html#addiconbyencoding">AddIconByEncoding</a></code>,
493 <code class="directive"><a href="../mod/mod_autoindex.html#addiconbytype">AddIconByType</a></code>,
494 <code class="directive"><a href="../mod/mod_autoindex.html#defaulticon">DefaultIcon</a></code>, <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>, <code class="directive"><a href="../mod/mod_dir.html#fallbackresource">FallbackResource</a></code>, <a href="mod_autoindex.html#indexoptions.fancyindexing"><code>FancyIndexing</code></a>, <code class="directive"><a href="../mod/mod_autoindex.html#headername">HeaderName</a></code>, <code class="directive"><a href="../mod/mod_autoindex.html#indexignore">IndexIgnore</a></code>, <code class="directive"><a href="../mod/mod_autoindex.html#indexoptions">IndexOptions</a></code>, <code class="directive"><a href="../mod/mod_autoindex.html#readmename">ReadmeName</a></code>,
497 <dt><a href="overrides.html#override-limit">Limit</a></dt>
500 Allow use of the directives controlling host access (<code class="directive"><a href="../mod/mod_access_compat.html#allow">Allow</a></code>, <code class="directive"><a href="../mod/mod_access_compat.html#deny">Deny</a></code> and <code class="directive"><a href="../mod/mod_access_compat.html#order">Order</a></code>).</dd>
505 <dt>Nonfatal=[Override|Unknown|All]</dt>
508 Allow use of AllowOverride option to treat invalid (unrecognized
509 or disallowed) directives in
510 .htaccess as nonfatal. Instead of causing an Internal Server
511 Error, disallowed or unrecognised directives will be ignored
512 and a warning logged:
514 <li><strong>Nonfatal=Override</strong> treats directives
515 forbidden by AllowOverride as nonfatal.</li>
516 <li><strong>Nonfatal=Unknown</strong> treats unknown directives
517 as nonfatal. This covers typos and directives implemented
518 by a module that's not present.</li>
519 <li><strong>Nonfatal=All</strong> treats both the above as nonfatal.</li>
521 <p>Note that a syntax error in a valid directive will still cause
522 an Internal Server Error.</p>
523 <div class="warning"><h3>Security</h3>
524 Nonfatal errors may have security implications for .htaccess users.
525 For example, if AllowOverride disallows AuthConfig, users'
526 configuration designed to restrict access to a site will be disabled.
530 <dt><a href="overrides.html#override-options">Options</a>[=<var>Option</var>,...]</dt>
533 Allow use of the directives controlling specific directory
534 features (<code class="directive"><a href="#options">Options</a></code> and
535 <code class="directive"><a href="../mod/mod_include.html#xbithack">XBitHack</a></code>).
536 An equal sign may be given followed by a comma-separated list, without
537 spaces, of options that may be set using the <code class="directive"><a href="#options">Options</a></code> command.
539 <div class="note"><h3>Implicit disabling of Options</h3>
540 <p>Even though the list of options that may be used in .htaccess files
541 can be limited with this directive, as long as any <code class="directive"><a href="#options">Options</a></code> directive is allowed any
542 other inherited option can be disabled by using the non-relative
543 syntax. In other words, this mechanism cannot force a specific option
544 to remain <em>set</em> while allowing any others to be set.
547 <div class="example"><p><code>
548 AllowOverride Options=Indexes,MultiViews
555 <pre class="prettyprint lang-config">AllowOverride AuthConfig Indexes</pre>
558 <p>In the example above, all directives that are neither in the group
559 <code>AuthConfig</code> nor <code>Indexes</code> cause an internal
562 <div class="note"><p>For security and performance reasons, do not set
563 <code>AllowOverride</code> to anything other than <code>None</code>
564 in your <code><Directory "/"></code> block. Instead, find (or
565 create) the <code><Directory></code> block that refers to the
566 directory where you're actually planning to place a
567 <code>.htaccess</code> file.</p>
572 <li><code class="directive"><a href="#accessfilename">AccessFileName</a></code></li>
573 <li><code class="directive"><a href="#allowoverridelist">AllowOverrideList</a></code></li>
574 <li><a href="../configuring.html">Configuration Files</a></li>
575 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
576 <li><a href="overrides.html">Override Class Index for .htaccess</a></li>
579 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
580 <div class="directive-section"><h2><a name="AllowOverrideList" id="AllowOverrideList">AllowOverrideList</a> <a name="allowoverridelist" id="allowoverridelist">Directive</a></h2>
581 <table class="directive">
582 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Individual directives that are allowed in
583 <code>.htaccess</code> files</td></tr>
584 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowOverrideList None|<var>directive</var>
585 [<var>directive-type</var>] ...</code></td></tr>
586 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowOverrideList None</code></td></tr>
587 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
588 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
589 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
591 <p>When the server finds an <code>.htaccess</code> file (as
592 specified by <code class="directive"><a href="#accessfilename">AccessFileName</a></code>),
593 it needs to know which directives declared in that file can override
594 earlier configuration directives.</p>
596 <div class="note"><h3>Only available in <Directory> sections</h3>
597 <code class="directive">AllowOverrideList</code> is valid only in
598 <code class="directive"><a href="#directory"><Directory></a></code>
599 sections specified without regular expressions, not in <code class="directive"><a href="#location"><Location></a></code>, <code class="directive"><a href="#directorymatch"><DirectoryMatch></a></code> or
600 <code class="directive"><a href="#files"><Files></a></code> sections.
603 <p>When this directive is set to <code>None</code> and <code class="directive"><a href="#allowoverride">AllowOverride</a></code> is set to <code>None</code>,
604 then <a href="#accessfilename">.htaccess</a> files are completely
605 ignored. In this case, the server will not even attempt to read
606 <code>.htaccess</code> files in the filesystem.</p>
610 <pre class="prettyprint lang-config">AllowOverride None
611 AllowOverrideList Redirect RedirectMatch</pre>
614 <p>In the example above, only the <code>Redirect</code> and
615 <code>RedirectMatch</code> directives are allowed. All others will
616 cause an Internal Server Error.</p>
620 <pre class="prettyprint lang-config">AllowOverride AuthConfig
621 AllowOverrideList CookieTracking CookieName</pre>
624 <p>In the example above, <code class="directive"><a href="#allowoverride">AllowOverride
625 </a></code> grants permission to the <code>AuthConfig</code>
626 directive grouping and <code class="directive">AllowOverrideList</code> grants
627 permission to only two directives from the <code>FileInfo</code> directive
628 grouping. All others will cause an Internal Server Error.</p>
632 <li><code class="directive"><a href="#accessfilename">AccessFileName</a></code></li>
633 <li><code class="directive"><a href="#allowoverride">AllowOverride</a></code></li>
634 <li><a href="../configuring.html">Configuration Files</a></li>
635 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
638 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
639 <div class="directive-section"><h2><a name="AsyncFilter" id="AsyncFilter">AsyncFilter</a> <a name="asyncfilter" id="asyncfilter">Directive</a></h2>
640 <table class="directive">
641 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Set the minimum filter type eligible for asynchronous handling</td></tr>
642 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AsyncFilter request|connection|network</code></td></tr>
643 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AsyncFilter request</code></td></tr>
644 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
645 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
646 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
647 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Only available from Apache 2.5.0 and later.</td></tr>
649 <p>This directive controls the minimum filter levels that are eligible
650 for asynchronous handling. This may be necessary to support legacy external
651 filters that did not handle meta buckets correctly.</p>
653 <p>If set to "network", asynchronous handling will be limited to the network
654 filter only. If set to "connection", all connection and network filters
655 will be eligible for asynchronous handling, including <code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code>.
656 If set to "request", all filters will be eligible for asynchronous handling.</p>
659 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
660 <div class="directive-section"><h2><a name="CGIMapExtension" id="CGIMapExtension">CGIMapExtension</a> <a name="cgimapextension" id="cgimapextension">Directive</a></h2>
661 <table class="directive">
662 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
664 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CGIMapExtension <var>cgi-path</var> <var>.extension</var></code></td></tr>
665 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
666 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
667 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
668 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
669 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>NetWare only</td></tr>
671 <p>This directive is used to control how Apache httpd finds the
672 interpreter used to run CGI scripts. For example, setting
673 <code>CGIMapExtension sys:\foo.nlm .foo</code> will
674 cause all CGI script files with a <code>.foo</code> extension to
675 be passed to the FOO interpreter.</p>
678 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
679 <div class="directive-section"><h2><a name="CGIPassAuth" id="CGIPassAuth">CGIPassAuth</a> <a name="cgipassauth" id="cgipassauth">Directive</a></h2>
680 <table class="directive">
681 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables passing HTTP authorization headers to scripts as CGI
683 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CGIPassAuth On|Off</code></td></tr>
684 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>CGIPassAuth Off</code></td></tr>
685 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
686 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig</td></tr>
687 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
688 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
689 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.4.13 and later</td></tr>
691 <p><code class="directive">CGIPassAuth</code> allows scripts access to HTTP
692 authorization headers such as <code>Authorization</code>, which is
693 required for scripts that implement HTTP Basic authentication.
694 Normally these HTTP headers are hidden from scripts. This is to disallow
695 scripts from seeing user ids and passwords used to access the server when
696 HTTP Basic authentication is enabled in the web server. This directive
697 should be used when scripts are allowed to implement HTTP Basic
700 <p>This directive can be used instead of the compile-time setting
701 <code>SECURITY_HOLE_PASS_AUTHORIZATION</code> which has been available
702 in previous versions of Apache HTTP Server.</p>
704 <p>The setting is respected by any modules which use
705 <code>ap_add_common_vars()</code>, such as <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>,
706 <code class="module"><a href="../mod/mod_cgid.html">mod_cgid</a></code>, <code class="module"><a href="../mod/mod_proxy_fcgi.html">mod_proxy_fcgi</a></code>,
707 <code class="module"><a href="../mod/mod_proxy_scgi.html">mod_proxy_scgi</a></code>, and so on. Notably, it affects
708 modules which don't handle the request in the usual sense but
709 still use this API; examples of this are <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
710 and <code class="module"><a href="../mod/mod_ext_filter.html">mod_ext_filter</a></code>. Third-party modules that don't
711 use <code>ap_add_common_vars()</code> may choose to respect the setting
715 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
716 <div class="directive-section"><h2><a name="CGIVar" id="CGIVar">CGIVar</a> <a name="cgivar" id="cgivar">Directive</a></h2>
717 <table class="directive">
718 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Controls how some CGI variables are set</td></tr>
719 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CGIVar <var>variable</var> <var>rule</var></code></td></tr>
720 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
721 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
722 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
723 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
724 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.4.21 and later</td></tr>
726 <p>This directive controls how some CGI variables are set.</p>
728 <p><strong>REQUEST_URI</strong> rules:</p>
730 <dt><code>original-uri</code> (default)</dt>
731 <dd>The value is taken from the original request line, and will not
732 reflect internal redirects or subrequests which change the requested
734 <dt><code>current-uri</code></dt>
735 <dd>The value reflects the resource currently being processed,
736 which may be different than the original request from the client
737 due to internal redirects or subrequests.</dd>
741 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
742 <div class="directive-section"><h2><a name="ContentDigest" id="ContentDigest">ContentDigest</a> <a name="contentdigest" id="contentdigest">Directive</a></h2>
743 <table class="directive">
744 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables the generation of <code>Content-MD5</code> HTTP Response
746 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ContentDigest On|Off</code></td></tr>
747 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ContentDigest Off</code></td></tr>
748 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
749 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
750 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
751 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
753 <p>This directive enables the generation of
754 <code>Content-MD5</code> headers as defined in RFC1864
755 respectively RFC2616.</p>
757 <p>MD5 is an algorithm for computing a "message digest"
758 (sometimes called "fingerprint") of arbitrary-length data, with
759 a high degree of confidence that any alterations in the data
760 will be reflected in alterations in the message digest.</p>
762 <p>The <code>Content-MD5</code> header provides an end-to-end
763 message integrity check (MIC) of the entity-body. A proxy or
764 client may check this header for detecting accidental
765 modification of the entity-body in transit. Example header:</p>
767 <div class="example"><p><code>
768 Content-MD5: AuLb7Dp1rqtRtxz2m9kRpA==
771 <p>Note that this can cause performance problems on your server
772 since the message digest is computed on every request (the
773 values are not cached).</p>
775 <p><code>Content-MD5</code> is only sent for documents served
776 by the <code class="module"><a href="../mod/core.html">core</a></code>, and not by any module. For example,
777 SSI documents, output from CGI scripts, and byte range responses
778 do not have this header.</p>
781 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
782 <div class="directive-section"><h2><a name="DefaultRuntimeDir" id="DefaultRuntimeDir">DefaultRuntimeDir</a> <a name="defaultruntimedir" id="defaultruntimedir">Directive</a></h2>
783 <table class="directive">
784 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server run-time files</td></tr>
785 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultRuntimeDir <var>directory-path</var></code></td></tr>
786 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultRuntimeDir DEFAULT_REL_RUNTIMEDIR (logs/)</code></td></tr>
787 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
788 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
789 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
790 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.4.2 and later</td></tr>
792 <p>The <code class="directive">DefaultRuntimeDir</code> directive sets the
793 directory in which the server will create various run-time files
794 (shared memory, locks, etc.). If set as a relative path, the full path
795 will be relative to <code class="directive">ServerRoot</code>.</p>
797 <p><strong>Example</strong></p>
798 <pre class="prettyprint lang-config">DefaultRuntimeDir scratch/</pre>
801 <p>The default location of <code class="directive">DefaultRuntimeDir</code> may be
802 modified by changing the <code>DEFAULT_REL_RUNTIMEDIR</code> #define
805 <p>Note: <code class="directive">ServerRoot</code> should be specified before this
806 directive is used. Otherwise, the default value of <code class="directive">ServerRoot</code>
807 would be used to set the base directory.</p>
812 <li><a href="../misc/security_tips.html#serverroot">the
813 security tips</a> for information on how to properly set
814 permissions on the <code class="directive">ServerRoot</code></li>
817 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
818 <div class="directive-section"><h2><a name="DefaultType" id="DefaultType">DefaultType</a> <a name="defaulttype" id="defaulttype">Directive</a></h2>
819 <table class="directive">
820 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>This directive has no effect other than to emit warnings
821 if the value is not <code>none</code>. In prior versions, DefaultType
822 would specify a default media type to assign to response content for
823 which no other media type configuration could be found.
825 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultType <var>media-type|none</var></code></td></tr>
826 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultType none</code></td></tr>
827 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
828 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
829 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
830 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
831 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>All choices except <code>none</code> are DISABLED for 2.3.x and later.
834 <p>This directive has been disabled. For backwards compatibility
835 of configuration files, it may be specified with the value
836 <code>none</code>, meaning no default media type. For example:</p>
838 <pre class="prettyprint lang-config">DefaultType None</pre>
841 <p><code>DefaultType None</code> is only available in
842 httpd-2.2.7 and later.</p>
844 <p>Use the mime.types configuration file and the
845 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code> to configure media
846 type assignments via file extensions, or the
847 <code class="directive"><a href="#forcetype">ForceType</a></code> directive to configure
848 the media type for specific resources. Otherwise, the server will
849 send the response without a Content-Type header field and the
850 recipient may attempt to guess the media type.</p>
854 <li><code class="directive"><a href="#undefine">UnDefine</a></code></li>
855 <li><code class="directive"><a href="#ifdefine">IfDefine</a></code></li>
858 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
859 <div class="directive-section"><h2><a name="Define" id="Define">Define</a> <a name="define" id="define">Directive</a></h2>
860 <table class="directive">
861 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Define a variable</td></tr>
862 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Define <var>parameter-name</var> [<var>parameter-value</var>]</code></td></tr>
863 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
864 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
865 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
867 <p>In its one parameter form, <code class="directive">Define</code> is
868 equivalent to passing the <code>-D</code> argument to
869 <code class="program"><a href="../programs/httpd.html">httpd</a></code>. It can be used to toggle the use of
870 <code class="directive"><a href="#ifdefine"><IfDefine></a></code>
871 sections without needing to alter <code>-D</code> arguments in any
874 <p>In addition to that, if the second parameter is given, a config variable
875 is set to this value. The variable can be used in the configuration using
876 the <code>${VAR}</code> syntax. The variable is always globally defined
877 and not limited to the scope of the surrounding config section.</p>
879 <pre class="prettyprint lang-config"><IfDefine TEST>
880 Define servername test.example.com
882 <IfDefine !TEST>
883 Define servername www.example.com
887 DocumentRoot "/var/www/${servername}/htdocs"</pre>
890 <p>Variable names may not contain colon ":" characters, to avoid clashes
891 with <code class="directive"><a href="../mod/mod_rewrite.html#rewritemap">RewriteMap</a></code>'s syntax.</p>
893 <p>While this directive is supported in virtual host context,
894 the changes it makes are visible to any later configuration
895 directives, beyond any enclosing virtual host.</p>
898 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
899 <div class="directive-section"><h2><a name="Directory" id="Directory"><Directory></a> <a name="directory" id="directory">Directive</a></h2>
900 <table class="directive">
901 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose a group of directives that apply only to the
902 named file-system directory, sub-directories, and their contents.</td></tr>
903 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Directory <var>directory-path</var>>
904 ... </Directory></code></td></tr>
905 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
906 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
907 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
909 <p><code class="directive"><Directory></code> and
910 <code></Directory></code> are used to enclose a group of
911 directives that will apply only to the named directory,
912 sub-directories of that directory, and the files within the respective
913 directories. Any directive that is allowed
914 in a directory context may be used. <var>Directory-path</var> is
915 either the full path to a directory, or a wild-card string using
916 Unix shell-style matching. In a wild-card string, <code>?</code> matches
917 any single character, and <code>*</code> matches any sequences of
918 characters. You may also use <code>[]</code> character ranges. None
919 of the wildcards match a `/' character, so <code><Directory
920 "/*/public_html"></code> will not match
921 <code>/home/user/public_html</code>, but <code><Directory
922 "/home/*/public_html"></code> will match. Example:</p>
924 <pre class="prettyprint lang-config"><Directory "/usr/local/httpd/htdocs">
925 Options Indexes FollowSymLinks
926 </Directory></pre>
929 <p>Directory paths <em>may</em> be quoted, if you like, however, it
930 <em>must</em> be quoted if the path contains spaces. This is because a
931 space would otherwise indicate the end of an argument.</p>
934 <p>Be careful with the <var>directory-path</var> arguments:
935 They have to literally match the filesystem path which Apache httpd uses
936 to access the files. Directives applied to a particular
937 <code><Directory></code> will not apply to files accessed from
938 that same directory via a different path, such as via different symbolic
942 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular
943 expressions</a> can also be used, with the addition of the
944 <code>~</code> character. For example:</p>
946 <pre class="prettyprint lang-config"><Directory ~ "^/www/[0-9]{3}">
948 </Directory></pre>
951 <p>would match directories in <code>/www/</code> that consisted of
954 <p>If multiple (non-regular expression) <code class="directive"><Directory></code> sections
955 match the directory (or one of its parents) containing a document,
956 then the directives are applied in the order of shortest match
957 first, interspersed with the directives from the <a href="#accessfilename">.htaccess</a> files. For example,
960 <pre class="prettyprint lang-config"><Directory "/">
964 <Directory "/home">
965 AllowOverride FileInfo
966 </Directory></pre>
969 <p>for access to the document <code>/home/web/dir/doc.html</code>
973 <li>Apply directive <code>AllowOverride None</code>
974 (disabling <code>.htaccess</code> files).</li>
976 <li>Apply directive <code>AllowOverride FileInfo</code> (for
977 directory <code>/home</code>).</li>
979 <li>Apply any <code>FileInfo</code> directives in
980 <code>/home/.htaccess</code>, <code>/home/web/.htaccess</code> and
981 <code>/home/web/dir/.htaccess</code> in that order.</li>
984 <p>Regular expressions are not considered until after all of the
985 normal sections have been applied. Then all of the regular
986 expressions are tested in the order they appeared in the
987 configuration file. For example, with</p>
989 <pre class="prettyprint lang-config"><Directory ~ "abc$">
990 # ... directives here ...
991 </Directory></pre>
994 <p>the regular expression section won't be considered until after
995 all normal <code class="directive"><Directory></code>s and
996 <code>.htaccess</code> files have been applied. Then the regular
997 expression will match on <code>/home/abc/public_html/abc</code> and
998 the corresponding <code class="directive"><Directory></code> will
1001 <p><strong>Note that the default access for
1002 <code><Directory "/"></code> is to permit all access.
1003 This means that Apache httpd will serve any file mapped from an URL. It is
1004 recommended that you change this with a block such
1007 <pre class="prettyprint lang-config"><Directory "/">
1009 </Directory></pre>
1012 <p><strong>and then override this for directories you
1013 <em>want</em> accessible. See the <a href="../misc/security_tips.html">Security Tips</a> page for more
1014 details.</strong></p>
1016 <p>The directory sections occur in the <code>httpd.conf</code> file.
1017 <code class="directive"><Directory></code> directives
1018 cannot nest, and cannot appear in a <code class="directive"><a href="#limit"><Limit></a></code> or <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section.</p>
1022 <li><a href="../sections.html">How <Directory>,
1023 <Location> and <Files> sections work</a> for an
1024 explanation of how these different sections are combined when a
1025 request is received</li>
1028 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1029 <div class="directive-section"><h2><a name="DirectoryMatch" id="DirectoryMatch"><DirectoryMatch></a> <a name="directorymatch" id="directorymatch">Directive</a></h2>
1030 <table class="directive">
1031 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose directives that apply to
1032 the contents of file-system directories matching a regular expression.</td></tr>
1033 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><DirectoryMatch <var>regex</var>>
1034 ... </DirectoryMatch></code></td></tr>
1035 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1036 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1037 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1039 <p><code class="directive"><DirectoryMatch></code> and
1040 <code></DirectoryMatch></code> are used to enclose a group
1041 of directives which will apply only to the named directory (and the files within),
1042 the same as <code class="directive"><a href="#directory"><Directory></a></code>.
1043 However, it takes as an argument a
1044 <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>. For example:</p>
1046 <pre class="prettyprint lang-config"><DirectoryMatch "^/www/(.+/)?[0-9]{3}/">
1048 </DirectoryMatch></pre>
1051 <p>matches directories in <code>/www/</code> (or any subdirectory thereof)
1052 that consist of three numbers.</p>
1054 <div class="note"><h3>Compatibility</h3>
1055 Prior to 2.3.9, this directive implicitly applied to sub-directories
1056 (like <code class="directive"><a href="#directory"><Directory></a></code>) and
1057 could not match the end of line symbol ($). In 2.3.9 and later,
1058 only directories that match the expression are affected by the enclosed
1062 <div class="note"><h3>Trailing Slash</h3>
1063 This directive applies to requests for directories that may or may
1064 not end in a trailing slash, so expressions that are anchored to the
1065 end of line ($) must be written with care.
1068 <p>From 2.4.8 onwards, named groups and backreferences are captured and
1069 written to the environment with the corresponding name prefixed with
1070 "MATCH_" and in upper case. This allows elements of paths to be referenced
1071 from within <a href="../expr.html">expressions</a> and modules like
1072 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
1073 (unnamed) backreferences are ignored. Use named groups instead.</p>
1075 <pre class="prettyprint lang-config"><DirectoryMatch "^/var/www/combined/(?<sitename>[^/]+)">
1076 Require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
1077 </DirectoryMatch></pre>
1082 <li><code class="directive"><a href="#directory"><Directory></a></code> for
1083 a description of how regular expressions are mixed in with normal
1084 <code class="directive"><Directory></code>s</li>
1085 <li><a href="../sections.html">How <Directory>, <Location> and
1086 <Files> sections work</a> for an explanation of how these different
1087 sections are combined when a request is received</li>
1090 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1091 <div class="directive-section"><h2><a name="DocumentRoot" id="DocumentRoot">DocumentRoot</a> <a name="documentroot" id="documentroot">Directive</a></h2>
1092 <table class="directive">
1093 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory that forms the main document tree visible
1094 from the web</td></tr>
1095 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DocumentRoot <var>directory-path</var></code></td></tr>
1096 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DocumentRoot "/usr/local/apache/htdocs"</code></td></tr>
1097 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1098 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1099 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1101 <p>This directive sets the directory from which <code class="program"><a href="../programs/httpd.html">httpd</a></code>
1102 will serve files. Unless matched by a directive like <code class="directive"><a href="../mod/mod_alias.html#alias">Alias</a></code>, the server appends the
1103 path from the requested URL to the document root to make the
1104 path to the document. Example:</p>
1106 <pre class="prettyprint lang-config">DocumentRoot "/usr/web"</pre>
1109 <p>then an access to
1110 <code>http://my.example.com/index.html</code> refers to
1111 <code>/usr/web/index.html</code>. If the <var>directory-path</var> is
1112 not absolute then it is assumed to be relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1114 <p>The <code class="directive">DocumentRoot</code> should be specified without
1115 a trailing slash.</p>
1119 <li><a href="../urlmapping.html#documentroot">Mapping URLs to Filesystem
1123 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1124 <div class="directive-section"><h2><a name="Else" id="Else"><Else></a> <a name="else" id="else">Directive</a></h2>
1125 <table class="directive">
1126 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if the condition of a
1127 previous <code class="directive"><a href="#if"><If></a></code> or
1128 <code class="directive"><a href="#elseif"><ElseIf></a></code> section is not
1129 satisfied by a request at runtime</td></tr>
1130 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Else> ... </Else></code></td></tr>
1131 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1132 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1133 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1134 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1136 <p>The <code class="directive"><Else></code> applies the enclosed
1137 directives if and only if the most recent
1138 <code class="directive"><If></code> or
1139 <code class="directive"><ElseIf></code> section
1140 in the same scope has not been applied.
1141 For example: In </p>
1143 <pre class="prettyprint lang-config"><If "-z req('Host')">
1151 <p> The <code class="directive"><If></code> would match HTTP/1.0
1152 requests without a <var>Host:</var> header and the
1153 <code class="directive"><Else></code> would match requests
1154 with a <var>Host:</var> header.</p>
1159 <li><code class="directive"><a href="#if"><If></a></code></li>
1160 <li><code class="directive"><a href="#elseif"><ElseIf></a></code></li>
1161 <li><a href="../sections.html">How <Directory>, <Location>,
1162 <Files> sections work</a> for an explanation of how these
1163 different sections are combined when a request is received.
1164 <code class="directive"><If></code>,
1165 <code class="directive"><ElseIf></code>, and
1166 <code class="directive"><Else></code> are applied last.</li>
1169 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1170 <div class="directive-section"><h2><a name="ElseIf" id="ElseIf"><ElseIf></a> <a name="elseif" id="elseif">Directive</a></h2>
1171 <table class="directive">
1172 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is satisfied
1173 by a request at runtime while the condition of a previous
1174 <code class="directive"><a href="#if"><If></a></code> or
1175 <code class="directive"><ElseIf></code> section is not
1177 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><ElseIf <var>expression</var>> ... </ElseIf></code></td></tr>
1178 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1179 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1180 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1181 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1183 <p>The <code class="directive"><ElseIf></code> applies the enclosed
1184 directives if and only if both the given condition evaluates to true and
1185 the most recent <code class="directive"><If></code> or
1186 <code class="directive"><ElseIf></code> section in the same scope has
1187 not been applied. For example: In </p>
1189 <pre class="prettyprint lang-config"><If "-R '10.1.0.0/16'">
1192 <ElseIf "-R '10.0.0.0/8'">
1200 <p>The <code class="directive"><ElseIf></code> would match if
1201 the remote address of a request belongs to the subnet 10.0.0.0/8 but
1202 not to the subnet 10.1.0.0/16.</p>
1207 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
1208 for a complete reference and more examples.</li>
1209 <li><code class="directive"><a href="#if"><If></a></code></li>
1210 <li><code class="directive"><a href="#else"><Else></a></code></li>
1211 <li><a href="../sections.html">How <Directory>, <Location>,
1212 <Files> sections work</a> for an explanation of how these
1213 different sections are combined when a request is received.
1214 <code class="directive"><If></code>,
1215 <code class="directive"><ElseIf></code>, and
1216 <code class="directive"><Else></code> are applied last.</li>
1219 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1220 <div class="directive-section"><h2><a name="EnableMMAP" id="EnableMMAP">EnableMMAP</a> <a name="enablemmap" id="enablemmap">Directive</a></h2>
1221 <table class="directive">
1222 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use memory-mapping to read files during delivery</td></tr>
1223 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableMMAP On|Off</code></td></tr>
1224 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableMMAP On</code></td></tr>
1225 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1226 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1227 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1228 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1230 <p>This directive controls whether the <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use
1231 memory-mapping if it needs to read the contents of a file during
1232 delivery. By default, when the handling of a request requires
1233 access to the data within a file -- for example, when delivering a
1234 server-parsed file using <code class="module"><a href="../mod/mod_include.html">mod_include</a></code> -- Apache httpd
1235 memory-maps the file if the OS supports it.</p>
1237 <p>This memory-mapping sometimes yields a performance improvement.
1238 But in some environments, it is better to disable the memory-mapping
1239 to prevent operational problems:</p>
1242 <li>On some multiprocessor systems, memory-mapping can reduce the
1243 performance of the <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</li>
1244 <li>Deleting or truncating a file while <code class="program"><a href="../programs/httpd.html">httpd</a></code>
1245 has it memory-mapped can cause <code class="program"><a href="../programs/httpd.html">httpd</a></code> to
1246 crash with a segmentation fault.
1250 <p>For server configurations that are vulnerable to these problems,
1251 you should disable memory-mapping of delivered files by specifying:</p>
1253 <pre class="prettyprint lang-config">EnableMMAP Off</pre>
1256 <p>For NFS mounted files, this feature may be disabled explicitly for
1257 the offending files by specifying:</p>
1259 <pre class="prettyprint lang-config"><Directory "/path-to-nfs-files">
1261 </Directory></pre>
1265 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1266 <div class="directive-section"><h2><a name="EnableSendfile" id="EnableSendfile">EnableSendfile</a> <a name="enablesendfile" id="enablesendfile">Directive</a></h2>
1267 <table class="directive">
1268 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use the kernel sendfile support to deliver files to the client</td></tr>
1269 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableSendfile On|Off</code></td></tr>
1270 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableSendfile Off</code></td></tr>
1271 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1272 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1273 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1274 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1275 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Default changed to Off in
1276 version 2.3.9.</td></tr>
1278 <p>This directive controls whether <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use the
1279 sendfile support from the kernel to transmit file contents to the client.
1280 By default, when the handling of a request requires no access
1281 to the data within a file -- for example, when delivering a
1282 static file -- Apache httpd uses sendfile to deliver the file contents
1283 without ever reading the file if the OS supports it.</p>
1285 <p>This sendfile mechanism avoids separate read and send operations,
1286 and buffer allocations. But on some platforms or within some
1287 filesystems, it is better to disable this feature to avoid
1288 operational problems:</p>
1291 <li>Some platforms may have broken sendfile support that the build
1292 system did not detect, especially if the binaries were built on
1293 another box and moved to such a machine with broken sendfile
1295 <li>On Linux the use of sendfile triggers TCP-checksum
1296 offloading bugs on certain networking cards when using IPv6.</li>
1297 <li>On Linux on Itanium, <code>sendfile</code> may be unable to handle
1298 files over 2GB in size.</li>
1299 <li>With a network-mounted <code class="directive"><a href="#documentroot">DocumentRoot</a></code> (e.g., NFS, SMB, CIFS, FUSE),
1300 the kernel may be unable to serve the network file through
1304 <p>For server configurations that are not vulnerable to these problems,
1305 you may enable this feature by specifying:</p>
1307 <pre class="prettyprint lang-config">EnableSendfile On</pre>
1310 <p>For network mounted files, this feature may be disabled explicitly
1311 for the offending files by specifying:</p>
1313 <pre class="prettyprint lang-config"><Directory "/path-to-nfs-files">
1315 </Directory></pre>
1317 <p>Please note that the per-directory and .htaccess configuration
1318 of <code class="directive">EnableSendfile</code> is not supported by
1319 <code class="module"><a href="../mod/mod_cache_disk.html">mod_cache_disk</a></code>.
1320 Only global definition of <code class="directive">EnableSendfile</code>
1321 is taken into account by the module.
1325 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1326 <div class="directive-section"><h2><a name="Error" id="Error">Error</a> <a name="error" id="error">Directive</a></h2>
1327 <table class="directive">
1328 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Abort configuration parsing with a custom error message</td></tr>
1329 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Error <var>message</var></code></td></tr>
1330 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1331 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1332 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1333 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1334 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.3.9 and later</td></tr>
1336 <p>If an error can be detected within the configuration, this
1337 directive can be used to generate a custom error message, and halt
1338 configuration parsing. The typical use is for reporting required
1339 modules which are missing from the configuration.</p>
1341 <pre class="prettyprint lang-config"># Example
1342 # ensure that mod_include is loaded
1343 <IfModule !include_module>
1344 Error "mod_include is required by mod_foo. Load it with LoadModule."
1347 # ensure that exactly one of SSL,NOSSL is defined
1348 <IfDefine SSL>
1349 <IfDefine NOSSL>
1350 Error "Both SSL and NOSSL are defined. Define only one of them."
1353 <IfDefine !SSL>
1354 <IfDefine !NOSSL>
1355 Error "Either SSL or NOSSL must be defined."
1357 </IfDefine></pre>
1362 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1363 <div class="directive-section"><h2><a name="ErrorDocument" id="ErrorDocument">ErrorDocument</a> <a name="errordocument" id="errordocument">Directive</a></h2>
1364 <table class="directive">
1365 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>What the server will return to the client
1366 in case of an error</td></tr>
1367 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ErrorDocument <var>error-code</var> <var>document</var></code></td></tr>
1368 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1369 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1370 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1371 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1373 <p>In the event of a problem or error, Apache httpd can be configured
1374 to do one of four things,</p>
1377 <li>output a simple hardcoded error message</li>
1379 <li>output a customized message</li>
1381 <li>internally redirect to a local <var>URL-path</var> to handle the
1384 <li>redirect to an external <var>URL</var> to handle the
1388 <p>The first option is the default, while options 2-4 are
1389 configured using the <code class="directive">ErrorDocument</code>
1390 directive, which is followed by the HTTP response code and a URL
1391 or a message. Apache httpd will sometimes offer additional information
1392 regarding the problem/error.</p>
1394 <p>From 2.4.13, <a href="../expr.html">expression syntax</a> can be
1395 used inside the directive to produce dynamic strings and URLs.</p>
1397 <p>URLs can begin with a slash (/) for local web-paths (relative
1398 to the <code class="directive"><a href="#documentroot">DocumentRoot</a></code>), or be a
1399 full URL which the client can resolve. Alternatively, a message
1400 can be provided to be displayed by the browser. Note that deciding
1401 whether the parameter is an URL, a path or a message is performed
1402 before any expression is parsed. Examples:</p>
1404 <pre class="prettyprint lang-config">ErrorDocument 500 http://example.com/cgi-bin/server-error.cgi
1405 ErrorDocument 404 /errors/bad_urls.php
1406 ErrorDocument 401 /subscription_info.html
1407 ErrorDocument 403 "Sorry, can't allow you access today"
1408 ErrorDocument 403 Forbidden!
1409 ErrorDocument 403 /errors/forbidden.py?referrer=%{escape:%{HTTP_REFERER}}</pre>
1412 <p>Additionally, the special value <code>default</code> can be used
1413 to specify Apache httpd's simple hardcoded message. While not required
1414 under normal circumstances, <code>default</code> will restore
1415 Apache httpd's simple hardcoded message for configurations that would
1416 otherwise inherit an existing <code class="directive">ErrorDocument</code>.</p>
1418 <pre class="prettyprint lang-config">ErrorDocument 404 /cgi-bin/bad_urls.pl
1420 <Directory "/web/docs">
1421 ErrorDocument 404 default
1422 </Directory></pre>
1425 <p>Note that when you specify an <code class="directive">ErrorDocument</code>
1426 that points to a remote URL (ie. anything with a method such as
1427 <code>http</code> in front of it), Apache HTTP Server will send a redirect to the
1428 client to tell it where to find the document, even if the
1429 document ends up being on the same server. This has several
1430 implications, the most important being that the client will not
1431 receive the original error status code, but instead will
1432 receive a redirect status code. This in turn can confuse web
1433 robots and other clients which try to determine if a URL is
1434 valid using the status code. In addition, if you use a remote
1435 URL in an <code>ErrorDocument 401</code>, the client will not
1436 know to prompt the user for a password since it will not
1437 receive the 401 status code. Therefore, <strong>if you use an
1438 <code>ErrorDocument 401</code> directive, then it must refer to a local
1439 document.</strong></p>
1441 <p>Microsoft Internet Explorer (MSIE) will by default ignore
1442 server-generated error messages when they are "too small" and substitute
1443 its own "friendly" error messages. The size threshold varies depending on
1444 the type of error, but in general, if you make your error document
1445 greater than 512 bytes, then MSIE will show the server-generated
1446 error rather than masking it. More information is available in
1447 Microsoft Knowledge Base article <a href="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q294807">Q294807</a>.</p>
1449 <p>Although most error messages can be overridden, there are certain
1450 circumstances where the internal messages are used regardless of the
1451 setting of <code class="directive"><a href="#errordocument">ErrorDocument</a></code>. In
1452 particular, if a malformed request is detected, normal request processing
1453 will be immediately halted and the internal error message returned.
1454 This is necessary to guard against security problems caused by
1457 <p>If you are using mod_proxy, you may wish to enable
1458 <code class="directive"><a href="../mod/mod_proxy.html#proxyerroroverride">ProxyErrorOverride</a></code> so that you can provide
1459 custom error messages on behalf of your Origin servers. If you don't enable ProxyErrorOverride,
1460 Apache httpd will not generate custom error documents for proxied content.</p>
1464 <li><a href="../custom-error.html">documentation of
1465 customizable responses</a></li>
1468 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1469 <div class="directive-section"><h2><a name="ErrorLog" id="ErrorLog">ErrorLog</a> <a name="errorlog" id="errorlog">Directive</a></h2>
1470 <table class="directive">
1471 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Location where the server will log errors</td></tr>
1472 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code> ErrorLog <var>file-path</var>|syslog[:[<var>facility</var>][:<var>tag</var>]]</code></td></tr>
1473 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ErrorLog logs/error_log (Unix) ErrorLog logs/error.log (Windows and OS/2)</code></td></tr>
1474 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1475 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1476 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1478 <p>The <code class="directive">ErrorLog</code> directive sets the name of
1479 the file to which the server will log any errors it encounters. If
1480 the <var>file-path</var> is not absolute then it is assumed to be
1481 relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1483 <pre class="prettyprint lang-config">ErrorLog "/var/log/httpd/error_log"</pre>
1486 <p>If the <var>file-path</var>
1487 begins with a pipe character "<code>|</code>" then it is assumed to be a
1488 command to spawn to handle the error log.</p>
1490 <pre class="prettyprint lang-config">ErrorLog "|/usr/local/bin/httpd_errors"</pre>
1493 <p>See the notes on <a href="../logs.html#piped">piped logs</a> for
1494 more information.</p>
1496 <p>Using <code>syslog</code> instead of a filename enables logging
1497 via syslogd(8) if the system supports it and if <code class="module"><a href="../mod/mod_syslog.html">mod_syslog</a></code>
1498 is loaded. The default is to use syslog facility <code>local7</code>,
1499 but you can override this by using the <code>syslog:<var>facility</var></code>
1500 syntax where <var>facility</var> can be one of the names usually documented in
1501 syslog(1). The facility is effectively global, and if it is changed
1502 in individual virtual hosts, the final facility specified affects the
1503 entire server. Same rules apply for the syslog tag, which by default
1504 uses the Apache binary name, <code>httpd</code> in most cases. You can
1505 also override this by using the <code>syslog::<var>tag</var></code>
1508 <pre class="prettyprint lang-config">ErrorLog syslog:user
1509 ErrorLog syslog:user:httpd.srv1
1510 ErrorLog syslog::httpd.srv2</pre>
1513 <p>Additional modules can provide their own ErrorLog providers. The syntax
1514 is similar to the <code>syslog</code> example above.</p>
1516 <p>SECURITY: See the <a href="../misc/security_tips.html#serverroot">security tips</a>
1517 document for details on why your security could be compromised
1518 if the directory where log files are stored is writable by
1519 anyone other than the user that starts the server.</p>
1520 <div class="warning"><h3>Note</h3>
1521 <p>When entering a file path on non-Unix platforms, care should be taken
1522 to make sure that only forward slashes are used even though the platform
1523 may allow the use of back slashes. In general it is a good idea to always
1524 use forward slashes throughout the configuration files.</p>
1529 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1530 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1533 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1534 <div class="directive-section"><h2><a name="ErrorLogFormat" id="ErrorLogFormat">ErrorLogFormat</a> <a name="errorlogformat" id="errorlogformat">Directive</a></h2>
1535 <table class="directive">
1536 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Format specification for error log entries</td></tr>
1537 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code> ErrorLogFormat [connection|request] <var>format</var></code></td></tr>
1538 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1539 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1540 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1542 <p><code class="directive">ErrorLogFormat</code> allows to specify what
1543 supplementary information is logged in the error log in addition to the
1544 actual log message.</p>
1546 <pre class="prettyprint lang-config">#Simple example
1547 ErrorLogFormat "[%t] [%l] [pid %P] %F: %E: [client %a] %M"</pre>
1550 <p>Specifying <code>connection</code> or <code>request</code> as first
1551 parameter allows to specify additional formats, causing additional
1552 information to be logged when the first message is logged for a specific
1553 connection or request, respectively. This additional information is only
1554 logged once per connection/request. If a connection or request is processed
1555 without causing any log message, the additional information is not logged
1558 <p>It can happen that some format string items do not produce output. For
1559 example, the Referer header is only present if the log message is
1560 associated to a request and the log message happens at a time when the
1561 Referer header has already been read from the client. If no output is
1562 produced, the default behavior is to delete everything from the preceding
1563 space character to the next space character. This means the log line is
1564 implicitly divided into fields on non-whitespace to whitespace transitions.
1565 If a format string item does not produce output, the whole field is
1566 omitted. For example, if the remote address <code>%a</code> in the log
1567 format <code>[%t] [%l] [%a] %M </code> is not available, the surrounding
1568 brackets are not logged either. Space characters can be escaped with a
1569 backslash to prevent them from delimiting a field. The combination '% '
1570 (percent space) is a zero-width field delimiter that does not produce any
1573 <p>The above behavior can be changed by adding modifiers to the format
1574 string item. A <code>-</code> (minus) modifier causes a minus to be logged if the
1575 respective item does not produce any output. In once-per-connection/request
1576 formats, it is also possible to use the <code>+</code> (plus) modifier. If an
1577 item with the plus modifier does not produce any output, the whole line is
1580 <p>A number as modifier can be used to assign a log severity level to a
1581 format item. The item will only be logged if the severity of the log
1582 message is not higher than the specified log severity level. The number can
1583 range from 1 (alert) over 4 (warn) and 7 (debug) to 15 (trace8).</p>
1585 <p>For example, here's what would happen if you added modifiers to
1586 the <code>%{Referer}i</code> token, which logs the
1587 <code>Referer</code> request header.</p>
1589 <table class="bordered"><tr class="header"><th>Modified Token</th><th>Meaning</th></tr>
1591 <td><code>%-{Referer}i</code></td>
1592 <td>Logs a <code>-</code> if <code>Referer</code> is not set.</td>
1595 <td><code>%+{Referer}i</code></td>
1596 <td>Omits the entire line if <code>Referer</code> is not set.</td>
1599 <td><code>%4{Referer}i</code></td>
1600 <td>Logs the <code>Referer</code> only if the log message severity
1601 is higher than 4.</td>
1605 <p>Some format string items accept additional parameters in braces.</p>
1607 <table class="bordered"><tr class="header"><th>Format String</th> <th>Description</th></tr>
1608 <tr><td><code>%%</code></td>
1609 <td>The percent sign</td></tr>
1610 <tr class="odd"><td><code>%a</code></td>
1611 <td>Client IP address and port of the request</td></tr>
1612 <tr><td><code>%{c}a</code></td>
1613 <td>Underlying peer IP address and port of the connection (see the
1614 <code class="module"><a href="../mod/mod_remoteip.html">mod_remoteip</a></code> module)</td></tr>
1615 <tr class="odd"><td><code>%A</code></td>
1616 <td>Local IP-address and port</td></tr>
1617 <tr><td><code>%{<em>name</em>}e</code></td>
1618 <td>Request environment variable <em>name</em></td></tr>
1619 <tr class="odd"><td><code>%E</code></td>
1620 <td>APR/OS error status code and string</td></tr>
1621 <tr><td><code>%F</code></td>
1622 <td>Source file name and line number of the log call</td></tr>
1623 <tr class="odd"><td><code>%{<em>name</em>}i</code></td>
1624 <td>Request header <em>name</em></td></tr>
1625 <tr><td><code>%k</code></td>
1626 <td>Number of keep-alive requests on this connection</td></tr>
1627 <tr class="odd"><td><code>%l</code></td>
1628 <td>Loglevel of the message</td></tr>
1629 <tr><td><code>%L</code></td>
1630 <td>Log ID of the request</td></tr>
1631 <tr class="odd"><td><code>%{c}L</code></td>
1632 <td>Log ID of the connection</td></tr>
1633 <tr><td><code>%{C}L</code></td>
1634 <td>Log ID of the connection if used in connection scope, empty otherwise</td></tr>
1635 <tr class="odd"><td><code>%m</code></td>
1636 <td>Name of the module logging the message</td></tr>
1637 <tr><td><code>%M</code></td>
1638 <td>The actual log message</td></tr>
1639 <tr class="odd"><td><code>%{<em>name</em>}n</code></td>
1640 <td>Request note <em>name</em></td></tr>
1641 <tr><td><code>%P</code></td>
1642 <td>Process ID of current process</td></tr>
1643 <tr class="odd"><td><code>%T</code></td>
1644 <td>Thread ID of current thread</td></tr>
1645 <tr><td><code>%{g}T</code></td>
1646 <td>System unique thread ID of current thread (the same ID as
1647 displayed by e.g. <code>top</code>; currently Linux only)</td></tr>
1648 <tr class="odd"><td><code>%t</code></td>
1649 <td>The current time</td></tr>
1650 <tr><td><code>%{u}t</code></td>
1651 <td>The current time including micro-seconds</td></tr>
1652 <tr class="odd"><td><code>%{cu}t</code></td>
1653 <td>The current time in compact ISO 8601 format, including
1654 micro-seconds</td></tr>
1655 <tr><td><code>%v</code></td>
1656 <td>The canonical <code class="directive"><a href="#servername">ServerName</a></code>
1657 of the current server.</td></tr>
1658 <tr class="odd"><td><code>%V</code></td>
1659 <td>The server name of the server serving the request according to the
1660 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code>
1662 <tr><td><code>\ </code> (backslash space)</td>
1663 <td>Non-field delimiting space</td></tr>
1664 <tr class="odd"><td><code>% </code> (percent space)</td>
1665 <td>Field delimiter (no output)</td></tr>
1668 <p>The log ID format <code>%L</code> produces a unique id for a connection
1669 or request. This can be used to correlate which log lines belong to the
1670 same connection or request, which request happens on which connection.
1671 A <code>%L</code> format string is also available in
1672 <code class="module"><a href="../mod/mod_log_config.html">mod_log_config</a></code> to allow to correlate access log entries
1673 with error log lines. If <code class="module"><a href="../mod/mod_unique_id.html">mod_unique_id</a></code> is loaded, its
1674 unique id will be used as log ID for requests.</p>
1676 <pre class="prettyprint lang-config">#Example (default format for threaded MPMs)
1677 ErrorLogFormat "[%{u}t] [%-m:%l] [pid %P:tid %T] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"</pre>
1680 <p>This would result in error messages such as:</p>
1682 <div class="example"><p><code>
1683 [Thu May 12 08:28:57.652118 2011] [core:error] [pid 8777:tid 4326490112] [client ::1:58619] File does not exist: /usr/local/apache2/htdocs/favicon.ico
1686 <p>Notice that, as discussed above, some fields are omitted
1687 entirely because they are not defined.</p>
1689 <pre class="prettyprint lang-config">#Example (similar to the 2.2.x format)
1690 ErrorLogFormat "[%t] [%l] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"</pre>
1693 <pre class="prettyprint lang-config">#Advanced example with request/connection log IDs
1694 ErrorLogFormat "[%{uc}t] [%-m:%-l] [R:%L] [C:%{C}L] %7F: %E: %M"
1695 ErrorLogFormat request "[%{uc}t] [R:%L] Request %k on C:%{c}L pid:%P tid:%T"
1696 ErrorLogFormat request "[%{uc}t] [R:%L] UA:'%+{User-Agent}i'"
1697 ErrorLogFormat request "[%{uc}t] [R:%L] Referer:'%+{Referer}i'"
1698 ErrorLogFormat connection "[%{uc}t] [C:%{c}L] local\ %a remote\ %A"</pre>
1704 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
1705 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1706 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1709 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1710 <div class="directive-section"><h2><a name="ExtendedStatus" id="ExtendedStatus">ExtendedStatus</a> <a name="extendedstatus" id="extendedstatus">Directive</a></h2>
1711 <table class="directive">
1712 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Keep track of extended status information for each
1714 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ExtendedStatus On|Off</code></td></tr>
1715 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ExtendedStatus Off[*]</code></td></tr>
1716 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
1717 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1718 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1720 <p>This option tracks additional data per worker about the
1721 currently executing request and creates a utilization summary.
1722 You can see these variables during runtime by configuring
1723 <code class="module"><a href="../mod/mod_status.html">mod_status</a></code>. Note that other modules may
1724 rely on this scoreboard.</p>
1726 <p>This setting applies to the entire server and cannot be
1727 enabled or disabled on a virtualhost-by-virtualhost basis.
1728 The collection of extended status information can slow down
1729 the server. Also note that this setting cannot be changed
1730 during a graceful restart.</p>
1733 <p>Note that loading <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> will change
1734 the default behavior to ExtendedStatus On, while other
1735 third party modules may do the same. Such modules rely on
1736 collecting detailed information about the state of all workers.
1737 The default is changed by <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> beginning
1738 with version 2.3.6. The previous default was always Off.</p>
1743 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1744 <div class="directive-section"><h2><a name="FileETag" id="FileETag">FileETag</a> <a name="fileetag" id="fileetag">Directive</a></h2>
1745 <table class="directive">
1746 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>File attributes used to create the ETag
1747 HTTP response header for static files</td></tr>
1748 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>FileETag <var>component</var> ...</code></td></tr>
1749 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>FileETag MTime Size</code></td></tr>
1750 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1751 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1752 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1753 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1754 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>The default used to be "INode MTime Size" in 2.3.14 and
1758 The <code class="directive">FileETag</code> directive configures the file
1759 attributes that are used to create the <code>ETag</code> (entity
1760 tag) response header field when the document is based on a static file.
1761 (The <code>ETag</code> value is used in cache management to save
1762 network bandwidth.) The
1763 <code class="directive">FileETag</code> directive allows you to choose
1764 which of these -- if any -- should be used. The recognized keywords are:
1768 <dt><strong>INode</strong></dt>
1769 <dd>The file's i-node number will be included in the calculation</dd>
1770 <dt><strong>MTime</strong></dt>
1771 <dd>The date and time the file was last modified will be included</dd>
1772 <dt><strong>Size</strong></dt>
1773 <dd>The number of bytes in the file will be included</dd>
1774 <dt><strong>All</strong></dt>
1775 <dd>All available fields will be used. This is equivalent to:
1776 <pre class="prettyprint lang-config">FileETag INode MTime Size</pre>
1778 <dt><strong>None</strong></dt>
1779 <dd>If a document is file-based, no <code>ETag</code> field will be
1780 included in the response</dd>
1783 <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
1784 keywords may be prefixed with either <code>+</code> or <code>-</code>,
1785 which allow changes to be made to the default setting inherited
1786 from a broader scope. Any keyword appearing without such a prefix
1787 immediately and completely cancels the inherited setting.</p>
1789 <p>If a directory's configuration includes
1790 <code>FileETag INode MTime Size</code>, and a
1791 subdirectory's includes <code>FileETag -INode</code>,
1792 the setting for that subdirectory (which will be inherited by
1793 any sub-subdirectories that don't override it) will be equivalent to
1794 <code>FileETag MTime Size</code>.</p>
1795 <div class="warning"><h3>Warning</h3>
1796 Do not change the default for directories or locations that have WebDAV
1797 enabled and use <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> as a storage provider.
1798 <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> uses <code>MTime Size</code>
1799 as a fixed format for <code>ETag</code> comparisons on conditional requests.
1800 These conditional requests will break if the <code>ETag</code> format is
1801 changed via <code class="directive">FileETag</code>.
1803 <div class="note"><h3>Server Side Includes</h3>
1804 An ETag is not generated for responses parsed by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
1805 since the response entity can change without a change of the INode, MTime, or Size
1806 of the static file with embedded SSI directives.
1811 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1812 <div class="directive-section"><h2><a name="Files" id="Files"><Files></a> <a name="files" id="files">Directive</a></h2>
1813 <table class="directive">
1814 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to matched
1816 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Files <var>filename</var>> ... </Files></code></td></tr>
1817 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1818 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1819 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1820 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1822 <p>The <code class="directive"><Files></code> directive
1823 limits the scope of the enclosed directives by filename. It is comparable
1824 to the <code class="directive"><a href="#directory"><Directory></a></code>
1825 and <code class="directive"><a href="#location"><Location></a></code>
1826 directives. It should be matched with a <code></Files></code>
1827 directive. The directives given within this section will be applied to
1828 any object with a basename (last component of filename) matching the
1829 specified filename. <code class="directive"><Files></code>
1830 sections are processed in the order they appear in the
1831 configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
1832 <code>.htaccess</code> files are read, but before <code class="directive"><a href="#location"><Location></a></code> sections. Note
1833 that <code class="directive"><Files></code> can be nested
1834 inside <code class="directive"><a href="#directory"><Directory></a></code> sections to restrict the
1835 portion of the filesystem they apply to.</p>
1837 <p>The <var>filename</var> argument should include a filename, or
1838 a wild-card string, where <code>?</code> matches any single character,
1839 and <code>*</code> matches any sequences of characters.</p>
1840 <pre class="prettyprint lang-config"><Files "cat.html">
1841 # Insert stuff that applies to cat.html here
1844 <Files "?at.*">
1845 # This would apply to cat.html, bat.html, hat.php and so on.
1846 </Files></pre>
1848 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
1849 can also be used, with the addition of the
1850 <code>~</code> character. For example:</p>
1852 <pre class="prettyprint lang-config"><Files ~ "\.(gif|jpe?g|png)$">
1854 </Files></pre>
1857 <p>would match most common Internet graphics formats. <code class="directive"><a href="#filesmatch"><FilesMatch></a></code> is preferred,
1860 <p>Note that unlike <code class="directive"><a href="#directory"><Directory></a></code> and <code class="directive"><a href="#location"><Location></a></code> sections, <code class="directive"><Files></code> sections can be used inside
1861 <code>.htaccess</code> files. This allows users to control access to
1862 their own files, at a file-by-file level.</p>
1867 <li><a href="../sections.html">How <Directory>, <Location>
1868 and <Files> sections work</a> for an explanation of how these
1869 different sections are combined when a request is received</li>
1872 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1873 <div class="directive-section"><h2><a name="FilesMatch" id="FilesMatch"><FilesMatch></a> <a name="filesmatch" id="filesmatch">Directive</a></h2>
1874 <table class="directive">
1875 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to regular-expression matched
1877 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><FilesMatch <var>regex</var>> ... </FilesMatch></code></td></tr>
1878 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1879 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1880 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1881 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1883 <p>The <code class="directive"><FilesMatch></code> directive
1884 limits the scope of the enclosed directives by filename, just as the
1885 <code class="directive"><a href="#files"><Files></a></code> directive
1886 does. However, it accepts a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular
1887 expression</a>. For example:</p>
1889 <pre class="prettyprint lang-config"><FilesMatch ".+\.(gif|jpe?g|png)$">
1891 </FilesMatch></pre>
1894 <p>would match most common Internet graphics formats.</p>
1896 <div class="note">The <code>.+</code> at the start of the regex ensures that
1897 files named <code>.png</code>, or <code>.gif</code>, for example,
1898 are not matched.</div>
1900 <p>From 2.4.8 onwards, named groups and backreferences are captured and
1901 written to the environment with the corresponding name prefixed with
1902 "MATCH_" and in upper case. This allows elements of files to be referenced
1903 from within <a href="../expr.html">expressions</a> and modules like
1904 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
1905 (unnamed) backreferences are ignored. Use named groups instead.</p>
1907 <pre class="prettyprint lang-config"><FilesMatch "^(?<sitename>[^/]+)">
1908 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
1909 </FilesMatch></pre>
1914 <li><a href="../sections.html">How <Directory>, <Location>
1915 and <Files> sections work</a> for an explanation of how these
1916 different sections are combined when a request is received</li>
1919 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1920 <div class="directive-section"><h2><a name="ForceType" id="ForceType">ForceType</a> <a name="forcetype" id="forcetype">Directive</a></h2>
1921 <table class="directive">
1922 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be served with the specified
1923 media type in the HTTP Content-Type header field</td></tr>
1924 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ForceType <var>media-type</var>|None</code></td></tr>
1925 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
1926 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1927 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1928 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1930 <p>When placed into an <code>.htaccess</code> file or a
1931 <code class="directive"><a href="#directory"><Directory></a></code>, or
1932 <code class="directive"><a href="#location"><Location></a></code> or
1933 <code class="directive"><a href="#files"><Files></a></code>
1934 section, this directive forces all matching files to be served
1935 with the content type identification given by
1936 <var>media-type</var>. For example, if you had a directory full of
1937 GIF files, but did not want to label them all with <code>.gif</code>,
1938 you might want to use:</p>
1940 <pre class="prettyprint lang-config">ForceType image/gif</pre>
1943 <p>Note that this directive overrides other indirect media type
1944 associations defined in mime.types or via the
1945 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code>.</p>
1947 <p>You can also override more general
1948 <code class="directive">ForceType</code> settings
1949 by using the value of <code>None</code>:</p>
1951 <pre class="prettyprint lang-config"># force all files to be image/gif:
1952 <Location "/images">
1956 # but normal mime-type associations here:
1957 <Location "/images/mixed">
1959 </Location></pre>
1962 <p>This directive primarily overrides the content types generated for
1963 static files served out of the filesystem. For resources other than
1964 static files, where the generator of the response typically specifies
1965 a Content-Type, this directive has no effect.</p>
1968 <div class="note"><h3>Note</h3>
1969 <p>If no handler is explicitly set for a request, the specified content
1970 type will also be used as the handler name. </p>
1972 <p>When explicit directives such as
1973 <code class="directive"><a href="#sethandler">SetHandler</a></code> or
1974 <code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code> do not apply
1975 to the current request, the internal handler name normally set by those
1976 directives is instead set to the content type specified by this directive.
1979 This is a historical behavior that some third-party modules
1980 (such as mod_php) may look for a "synthetic" content type used only to
1981 signal the module to take responsibility for the matching request.
1984 <p>Configurations that rely on such "synthetic" types should be avoided.
1985 Additionally, configurations that restrict access to
1986 <code class="directive"><a href="#sethandler">SetHandler</a></code> or
1987 <code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code> should
1988 restrict access to this directive as well.</p>
1993 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1994 <div class="directive-section"><h2><a name="GprofDir" id="GprofDir">GprofDir</a> <a name="gprofdir" id="gprofdir">Directive</a></h2>
1995 <table class="directive">
1996 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory to write gmon.out profiling data to. </td></tr>
1997 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>GprofDir <var>/tmp/gprof/</var>|<var>/tmp/gprof/</var>%</code></td></tr>
1998 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1999 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2000 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2002 <p>When the server has been compiled with gprof profiling support,
2003 <code class="directive">GprofDir</code> causes <code>gmon.out</code> files to
2004 be written to the specified directory when the process exits. If the
2005 argument ends with a percent symbol ('%'), subdirectories are created
2006 for each process id.</p>
2008 <p>This directive currently only works with the <code class="module"><a href="../mod/prefork.html">prefork</a></code>
2012 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2013 <div class="directive-section"><h2><a name="HostnameLookups" id="HostnameLookups">HostnameLookups</a> <a name="hostnamelookups" id="hostnamelookups">Directive</a></h2>
2014 <table class="directive">
2015 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables DNS lookups on client IP addresses</td></tr>
2016 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>HostnameLookups On|Off|Double</code></td></tr>
2017 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>HostnameLookups Off</code></td></tr>
2018 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2019 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2020 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2022 <p>This directive enables DNS lookups so that host names can be
2023 logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
2024 The value <code>Double</code> refers to doing double-reverse
2025 DNS lookup. That is, after a reverse lookup is performed, a forward
2026 lookup is then performed on that result. At least one of the IP
2027 addresses in the forward lookup must match the original
2028 address. (In "tcpwrappers" terminology this is called
2029 <code>PARANOID</code>.)</p>
2031 <p>Regardless of the setting, when <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code> is
2032 used for controlling access by hostname, a double reverse lookup
2033 will be performed. This is necessary for security. Note that the
2034 result of this double-reverse isn't generally available unless you
2035 set <code>HostnameLookups Double</code>. For example, if only
2036 <code>HostnameLookups On</code> and a request is made to an object
2037 that is protected by hostname restrictions, regardless of whether
2038 the double-reverse fails or not, CGIs will still be passed the
2039 single-reverse result in <code>REMOTE_HOST</code>.</p>
2041 <p>The default is <code>Off</code> in order to save the network
2042 traffic for those sites that don't truly need the reverse
2043 lookups done. It is also better for the end users because they
2044 don't have to suffer the extra latency that a lookup entails.
2045 Heavily loaded sites should leave this directive
2046 <code>Off</code>, since DNS lookups can take considerable
2047 amounts of time. The utility <code class="program"><a href="../programs/logresolve.html">logresolve</a></code>, compiled by
2048 default to the <code>bin</code> subdirectory of your installation
2049 directory, can be used to look up host names from logged IP addresses
2052 <p>Finally, if you have <a href="mod_authz_host.html#reqhost">hostname-based Require
2053 directives</a>, a hostname lookup will be performed regardless of
2054 the setting of <code>HostnameLookups</code>.</p>
2057 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2058 <div class="directive-section"><h2><a name="HttpProtocolOptions" id="HttpProtocolOptions">HttpProtocolOptions</a> <a name="httpprotocoloptions" id="httpprotocoloptions">Directive</a></h2>
2059 <table class="directive">
2060 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Modify restrictions on HTTP Request Messages</td></tr>
2061 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>HttpProtocolOptions [Strict|Unsafe] [RegisteredMethods|LenientMethods]
2062 [Allow0.9|Require1.0]</code></td></tr>
2063 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>HttpProtocolOptions Strict LenientMethods Allow0.9</code></td></tr>
2064 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2065 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2066 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2067 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.2.32 or 2.4.24 and later</td></tr>
2069 <p>This directive changes the rules applied to the HTTP Request Line
2070 (<a href="https://tools.ietf.org/html/rfc7230#section-3.1.1">RFC 7230 §3.1.1</a>) and the HTTP Request Header Fields
2071 (<a href="https://tools.ietf.org/html/rfc7230#section-3.2">RFC 7230 §3.2</a>), which are now applied by default or using
2072 the <code>Strict</code> option. Due to legacy modules, applications or
2073 custom user-agents which must be deprecated the <code>Unsafe</code>
2074 option has been added to revert to the legacy behaviors.</p>
2076 <p>These rules are applied prior to request processing,
2077 so must be configured at the global or default (first) matching
2078 virtual host section, by IP/port interface (and not by name)
2081 <p>The directive accepts three parameters from the following list
2082 of choices, applying the default to the ones not specified:</p>
2085 <dt>Strict|Unsafe</dt>
2087 <p>Prior to the introduction of this directive, the Apache HTTP Server
2088 request message parsers were tolerant of a number of forms of input
2089 which did not conform to the protocol.
2090 <a href="https://tools.ietf.org/html/rfc7230#section-9.4">RFC 7230 §9.4 Request Splitting</a> and
2091 <a href="https://tools.ietf.org/html/rfc7230#section-9.5">§9.5 Response Smuggling</a> call out only two of the potential
2092 risks of accepting non-conformant request messages, while
2093 <a href="https://tools.ietf.org/html/rfc7230#section-3.5">RFC 7230 §3.5</a> "Message Parsing Robustness" identify the
2094 risks of accepting obscure whitespace and request message formatting.
2095 As of the introduction of this directive, all grammar rules of the
2096 specification are enforced in the default <code>Strict</code> operating
2097 mode, and the strict whitespace suggested by section 3.5 is enforced
2098 and cannot be relaxed.</p>
2100 <div class="warning"><h3>Security risks of Unsafe</h3>
2101 <p>Users are strongly cautioned against toggling the <code>Unsafe</code>
2102 mode of operation, particularly on outward-facing, publicly accessible
2103 server deployments. If an interface is required for faulty monitoring
2104 or other custom service consumers running on an intranet, users should
2105 toggle the Unsafe option only on a specific virtual host configured
2106 to service their internal private network.</p>
2109 <div class="example"><h3>Example of a request leading to HTTP 400 with Strict mode</h3><p><code>
2111 # Missing CRLF<br />
2114 <div class="warning"><h3>Command line tools and CRLF</h3>
2115 <p>Some tools need to be forced to use CRLF, otherwise httpd will return
2116 a HTTP 400 response like described in the above use case. For example,
2117 the <strong>OpenSSL s_client needs the -crlf parameter to work
2118 properly</strong>.</p>
2119 <p>The <code class="directive"><a href="../mod/mod_dumpio.html#dumpioinput">DumpIOInput</a></code> directive
2120 can help while reviewing the HTTP request to identify issues like the
2121 absence of CRLF.</p>
2124 <dt>RegisteredMethods|LenientMethods</dt>
2126 <p><a href="https://tools.ietf.org/html/rfc7231#section-4.1">RFC 7231 §4.1</a> "Request Methods" "Overview" requires that
2127 origin servers shall respond with a HTTP 501 status code when an
2128 unsupported method is encountered in the request line.
2129 This already happens when the <code>LenientMethods</code> option is used,
2130 but administrators may wish to toggle the <code>RegisteredMethods</code>
2131 option and register any non-standard methods using the
2132 <code class="directive"><a href="#registerhttpmethod">RegisterHttpMethod</a></code>
2133 directive, particularly if the <code>Unsafe</code>
2134 option has been toggled.</p>
2136 <div class="warning"><h3>Forward Proxy compatibility</h3>
2137 <p>The <code>RegisteredMethods</code> option should <strong>not</strong>
2138 be toggled for forward proxy hosts, as the methods supported by the
2139 origin servers are unknown to the proxy server.</p>
2142 <div class="example"><h3>Example of a request leading to HTTP 501 with LenientMethods mode</h3><p><code>
2144 # Unknown HTTP method<br />
2145 WOW / HTTP/1.0\r\n\r\n<br /><br />
2146 # Lowercase HTTP method<br />
2147 get / HTTP/1.0\r\n\r\n<br />
2150 <dt>Allow0.9|Require1.0</dt>
2152 <p><a href="https://tools.ietf.org/html/rfc2616#section-19.6">RFC 2616 §19.6</a> "Compatibility With Previous Versions" had
2153 encouraged HTTP servers to support legacy HTTP/0.9 requests. RFC 7230
2154 supersedes this with "The expectation to support HTTP/0.9 requests has
2155 been removed" and offers additional comments in
2156 <a href="https://tools.ietf.org/html/rfc7230#appendix-A">RFC 7230 Appendix A</a>. The <code>Require1.0</code> option allows
2157 the user to remove support of the default <code>Allow0.9</code> option's
2160 <div class="example"><h3>Example of a request leading to HTTP 400 with Require1.0 mode</h3><p><code>
2162 # Unsupported HTTP version<br />
2167 <p>Reviewing the messages logged to the
2168 <code class="directive"><a href="#errorlog">ErrorLog</a></code>, configured with
2169 <code class="directive"><a href="#loglevel">LogLevel</a></code> <code>debug</code> level,
2170 can help identify such faulty requests along with their origin.
2171 Users should pay particular attention to the 400 responses in the access
2172 log for invalid requests which were unexpectedly rejected.</p>
2175 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2176 <div class="directive-section"><h2><a name="If" id="If"><If></a> <a name="if" id="if">Directive</a></h2>
2177 <table class="directive">
2178 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is
2179 satisfied by a request at runtime</td></tr>
2180 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><If <var>expression</var>> ... </If></code></td></tr>
2181 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2182 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2183 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2184 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2186 <p>The <code class="directive"><If></code> directive
2187 evaluates an expression at runtime, and applies the enclosed
2188 directives if and only if the expression evaluates to true.
2191 <pre class="prettyprint lang-config"><If "-z req('Host')"></pre>
2194 <p>would match HTTP/1.0 requests without a <var>Host:</var> header.
2195 Expressions may contain various shell-like operators for string
2196 comparison (<code>==</code>, <code>!=</code>, <code><</code>, ...),
2197 integer comparison (<code>-eq</code>, <code>-ne</code>, ...),
2198 and others (<code>-n</code>, <code>-z</code>, <code>-f</code>, ...).
2199 It is also possible to use regular expressions, </p>
2201 <pre class="prettyprint lang-config"><If "%{QUERY_STRING} =~ /(delete|commit)=.*?elem/"></pre>
2204 <p>shell-like pattern matches and many other operations. These operations
2205 can be done on request headers (<code>req</code>), environment variables
2206 (<code>env</code>), and a large number of other properties. The full
2207 documentation is available in <a href="../expr.html">Expressions in
2208 Apache HTTP Server</a>.</p>
2210 <p>Only directives that support the <a href="directive-dict.html#Context">directory context</a> can be used within this configuration section.</p>
2212 <div class="note"><h3>Not a scripting language</h3>
2213 The name of this directive is very familiar to programmers and admins
2214 but it should not be confused with its counterpart in scripting languages.
2215 For example, the current implementation does not contemplate the possibility
2216 of having a <code class="directive"><If></code> section inside another
2217 one (the inner <code class="directive"><If></code> will be ignored).
2220 <div class="warning">
2221 Certain variables, such as <code>CONTENT_TYPE</code> and other
2222 response headers, are set after <If> conditions have already
2223 been evaluated, and so will not be available to use in this
2230 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
2231 for a complete reference and more examples.</li>
2232 <li><code class="directive"><a href="#elseif"><ElseIf></a></code></li>
2233 <li><code class="directive"><a href="#else"><Else></a></code></li>
2234 <li><a href="../sections.html">How <Directory>, <Location>,
2235 <Files> sections work</a> for an explanation of how these
2236 different sections are combined when a request is received.
2237 <code class="directive"><If></code>,
2238 <code class="directive"><ElseIf></code>, and
2239 <code class="directive"><Else></code> are applied last.</li>
2242 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2243 <div class="directive-section"><h2><a name="IfDefine" id="IfDefine"><IfDefine></a> <a name="ifdefine" id="ifdefine">Directive</a></h2>
2244 <table class="directive">
2245 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that will be processed only
2246 if a test is true at startup</td></tr>
2247 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfDefine [!]<var>parameter-name</var>> ...
2248 </IfDefine></code></td></tr>
2249 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2250 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2251 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2252 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2254 <p>The <code><IfDefine <var>test</var>>...</IfDefine>
2255 </code> section is used to mark directives that are conditional. The
2256 directives within an <code class="directive"><IfDefine></code>
2257 section are only processed if the <var>test</var> is true. If <var>
2258 test</var> is false, everything between the start and end markers is
2261 <p>The <var>test</var> in the <code class="directive"><IfDefine></code> section directive can be one of two forms:</p>
2264 <li><var>parameter-name</var></li>
2266 <li><code>!</code><var>parameter-name</var></li>
2269 <p>In the former case, the directives between the start and end
2270 markers are only processed if the parameter named
2271 <var>parameter-name</var> is defined. The second format reverses
2272 the test, and only processes the directives if
2273 <var>parameter-name</var> is <strong>not</strong> defined.</p>
2275 <p>The <var>parameter-name</var> argument is a define as given on the
2276 <code class="program"><a href="../programs/httpd.html">httpd</a></code> command line via <code>-D<var>parameter</var>
2277 </code> at the time the server was started or by the <code class="directive"><a href="#define">Define</a></code> directive.</p>
2279 <p><code class="directive"><IfDefine></code> sections are
2280 nest-able, which can be used to implement simple
2281 multiple-parameter tests. Example:</p>
2283 <div class="example"><p><code>httpd -DReverseProxy -DUseCache -DMemCache ...</code></p></div>
2284 <pre class="prettyprint lang-config"><IfDefine ReverseProxy>
2285 LoadModule proxy_module modules/mod_proxy.so
2286 LoadModule proxy_http_module modules/mod_proxy_http.so
2287 <IfDefine UseCache>
2288 LoadModule cache_module modules/mod_cache.so
2289 <IfDefine MemCache>
2290 LoadModule mem_cache_module modules/mod_mem_cache.so
2292 <IfDefine !MemCache>
2293 LoadModule cache_disk_module modules/mod_cache_disk.so
2296 </IfDefine></pre>
2300 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2301 <div class="directive-section"><h2><a name="IfDirective" id="IfDirective"><IfDirective></a> <a name="ifdirective" id="ifdirective">Directive</a></h2>
2302 <table class="directive">
2303 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that are processed conditional on the
2304 presence or absence of a specific directive</td></tr>
2305 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfDirective [!]<var>directive-name</var>> ...
2306 </IfDirective></code></td></tr>
2307 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2308 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2309 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2310 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2312 <p>The <code><IfDirective <var>test</var>>...</IfDirective></code>
2313 section is used to mark directives that are conditional on the presence of
2314 a specific directive. The directives within an <code class="directive"><IfDirective></code> section are only processed if the <var>test</var>
2315 is true. If <var>test</var> is false, everything between the start and
2316 end markers is ignored.</p>
2318 <p>The <var>test</var> in the <code class="directive"><IfDirective></code> section can be one of two forms:</p>
2321 <li><var>directive-name</var></li>
2323 <li>!<var>directive-name</var></li>
2326 <p>In the former case, the directives between the start and end
2327 markers are only processed if a directive of the given name is
2328 available at the time of processing. The second format reverses the test,
2329 and only processes the directives if <var>directive-name</var> is
2330 <strong>not</strong> available.</p>
2332 <div class="note">This section should only be used if you need to have one
2333 configuration file that works across multiple versions of
2334 <code class="program"><a href="../programs/httpd.html">httpd</a></code>, regardless of whether a particular
2335 directive is available. In normal operation, directives need not
2336 be placed in <code class="directive"><IfDirective></code>
2341 <li><code class="directive"><a href="#ifsection"><IfSection></a></code></li>
2344 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2345 <div class="directive-section"><h2><a name="IfFile" id="IfFile"><IfFile></a> <a name="iffile" id="iffile">Directive</a></h2>
2346 <table class="directive">
2347 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that will be processed only
2348 if file exists at startup</td></tr>
2349 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfFile [!]<var>parameter-name</var>> ...
2350 </IfFile></code></td></tr>
2351 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2352 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2353 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2354 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2356 <p>The <code><IfFile <var>filename</var>>...</IfFile>
2357 </code> section is used to mark directives that are conditional on
2358 the existence of a file on disk. The directives within an
2359 <code class="directive"><IfFile></code> section are only
2360 processed if the <var>filename</var> exists. If <var> filename</var>
2361 doesn't exist, everything between the start and end markers is
2362 ignored. <var>filename</var> can be an absolute path or a path
2363 relative to the server root.</p>
2365 <p>The <var>filename</var> in the <code class="directive"><IfFile
2366 ></code> section directive can take the same forms as the
2367 <var>test</var> variable in the <code class="directive"><IfDefine
2368 ></code> section, i.e. the test can be negated if the <code>
2369 !</code> character is placed directly before <var>filename</var>.
2372 <p>If a relative <var>filename</var> is supplied, the check is
2373 <code class="directive">ServerRoot</code> relative. In the case where
2374 this directive occurs before the <code class="directive">ServerRoot</code>,
2375 the path will be checked relative to the compiled-in server root or
2376 the server root passed in on the command line via the <code>-d</code>
2381 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2382 <div class="directive-section"><h2><a name="IfModule" id="IfModule"><IfModule></a> <a name="ifmodule" id="ifmodule">Directive</a></h2>
2383 <table class="directive">
2384 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that are processed conditional on the
2385 presence or absence of a specific module</td></tr>
2386 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfModule [!]<var>module-file</var>|<var>module-identifier</var>> ...
2387 </IfModule></code></td></tr>
2388 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2389 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2390 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2391 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2393 <p>The <code><IfModule <var>test</var>>...</IfModule></code>
2394 section is used to mark directives that are conditional on the presence of
2395 a specific module. The directives within an <code class="directive"><IfModule></code> section are only processed if the <var>test</var>
2396 is true. If <var>test</var> is false, everything between the start and
2397 end markers is ignored.</p>
2399 <p>The <var>test</var> in the <code class="directive"><IfModule></code> section directive can be one of two forms:</p>
2402 <li><var>module</var></li>
2404 <li>!<var>module</var></li>
2407 <p>In the former case, the directives between the start and end
2408 markers are only processed if the module named <var>module</var>
2409 is included in Apache httpd -- either compiled in or
2410 dynamically loaded using <code class="directive"><a href="../mod/mod_so.html#loadmodule">LoadModule</a></code>. The second format reverses the test,
2411 and only processes the directives if <var>module</var> is
2412 <strong>not</strong> included.</p>
2414 <p>The <var>module</var> argument can be either the module identifier or
2415 the file name of the module, at the time it was compiled. For example,
2416 <code>rewrite_module</code> is the identifier and
2417 <code>mod_rewrite.c</code> is the file name. If a module consists of
2418 several source files, use the name of the file containing the string
2419 <code>STANDARD20_MODULE_STUFF</code>.</p>
2421 <p><code class="directive"><IfModule></code> sections are
2422 nest-able, which can be used to implement simple multiple-module
2425 <div class="note">This section should only be used if you need to have one
2426 configuration file that works whether or not a specific module
2427 is available. In normal operation, directives need not be
2428 placed in <code class="directive"><IfModule></code>
2432 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2433 <div class="directive-section"><h2><a name="IfSection" id="IfSection"><IfSection></a> <a name="ifsection" id="ifsection">Directive</a></h2>
2434 <table class="directive">
2435 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that are processed conditional on the
2436 presence or absence of a specific section directive</td></tr>
2437 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfSection [!]<var>section-name</var>> ...
2438 </IfSection></code></td></tr>
2439 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2440 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2441 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2442 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2444 <p>The <code><IfSection
2445 <var>test</var>>...</IfSection></code> section is used
2446 to mark directives that are conditional on the presence of a
2447 specific section directive. A section directive is any directive
2448 such as <code class="directive"><VirtualHost></code> which
2449 encloses other directives, and has a directive name with a leading
2452 <p>The directives within an <code class="directive"><IfSection></code> section are only processed if the <var>test</var>
2453 is true. If <var>test</var> is false, everything between the start and
2454 end markers is ignored.</p>
2456 <p>The <var>section-name</var> must be specified without either
2457 the leading "<" or closing ">". The <var>test</var> in the
2458 <code class="directive"><IfSection></code> section can be one
2462 <li><var>section-name</var></li>
2463 <li>!<var>section-name</var></li>
2466 <p>In the former case, the directives between the start and end
2467 markers are only processed if a section directive of the given
2468 name is available at the time of processing. The second format
2469 reverses the test, and only processes the directives if
2470 <var>section-name</var> is <strong>not</strong> an available
2471 section directive.</p>
2475 <pre class="prettyprint lang-config"><IfSection VirtualHost>
2477 </IfSection></pre>
2480 <div class="note">This section should only be used if you need to have one
2481 configuration file that works across multiple versions of <code class="program"><a href="../programs/httpd.html">httpd</a></code>,
2482 regardless of whether a particular section directive is
2483 available. In normal operation, directives need not be placed in
2484 <code class="directive"><IfSection></code> sections.</div>
2488 <li><code class="directive"><a href="#ifdirective"><IfDirective></a></code></li>
2491 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2492 <div class="directive-section"><h2><a name="Include" id="Include">Include</a> <a name="include" id="include">Directive</a></h2>
2493 <table class="directive">
2494 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2495 the server configuration files</td></tr>
2496 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Include <var>file-path</var>|<var>directory-path</var>|<var>wildcard</var></code></td></tr>
2497 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2498 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2499 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2500 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Directory
2501 wildcard matching available in 2.3.6 and later</td></tr>
2503 <p>This directive allows inclusion of other configuration files
2504 from within the server configuration files.</p>
2506 <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used
2507 in the filename or directory parts of the path to include several files
2508 at once, in alphabetical order. In addition, if
2509 <code class="directive">Include</code> points to a directory, rather than a file,
2510 Apache httpd will read all files in that directory and any subdirectory.
2511 However, including entire directories is not recommended, because it is
2512 easy to accidentally leave temporary files in a directory that can cause
2513 <code class="program"><a href="../programs/httpd.html">httpd</a></code> to fail. Instead, we encourage you to use the
2514 wildcard syntax shown below, to include files that match a particular
2515 pattern, such as *.conf, for example.</p>
2517 <p>The <code class="directive"><a href="#include">Include</a></code> directive will
2518 <strong>fail with an error</strong> if a wildcard expression does not
2519 match any file. The <code class="directive"><a href="#includeoptional">IncludeOptional</a></code>
2520 directive can be used if non-matching wildcards should be ignored.</p>
2522 <p>The file path specified may be an absolute path, or may be relative
2523 to the <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory.</p>
2527 <pre class="prettyprint lang-config">Include /usr/local/apache2/conf/ssl.conf
2528 Include /usr/local/apache2/conf/vhosts/*.conf</pre>
2531 <p>Or, providing paths relative to your <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory:</p>
2533 <pre class="prettyprint lang-config">Include conf/ssl.conf
2534 Include conf/vhosts/*.conf</pre>
2537 <p>Wildcards may be included in the directory or file portion of the
2538 path. This example will fail if there is no subdirectory in conf/vhosts
2539 that contains at least one *.conf file:</p>
2541 <pre class="prettyprint lang-config">Include conf/vhosts/*/*.conf</pre>
2544 <p>Alternatively, the following command will just be ignored in case of
2545 missing files or directories:</p>
2547 <pre class="prettyprint lang-config">IncludeOptional conf/vhosts/*/*.conf</pre>
2553 <li><code class="directive"><a href="#includeoptional">IncludeOptional</a></code></li>
2554 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2557 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2558 <div class="directive-section"><h2><a name="IncludeOptional" id="IncludeOptional">IncludeOptional</a> <a name="includeoptional" id="includeoptional">Directive</a></h2>
2559 <table class="directive">
2560 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2561 the server configuration files</td></tr>
2562 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>IncludeOptional <var>file-path</var>|<var>directory-path</var>|<var>wildcard</var></code></td></tr>
2563 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2564 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2565 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2566 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in 2.3.6 and later</td></tr>
2568 <p>This directive allows inclusion of other configuration files
2569 from within the server configuration files. It works identically to the
2570 <code class="directive"><a href="#include">Include</a></code> directive, with the
2571 exception that if wildcards do not match any file or directory, the
2572 <code class="directive"><a href="#includeoptional">IncludeOptional</a></code> directive will be
2573 silently ignored instead of causing an error.</p>
2577 <li><code class="directive"><a href="#include">Include</a></code></li>
2578 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2581 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2582 <div class="directive-section"><h2><a name="KeepAlive" id="KeepAlive">KeepAlive</a> <a name="keepalive" id="keepalive">Directive</a></h2>
2583 <table class="directive">
2584 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables HTTP persistent connections</td></tr>
2585 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAlive On|Off</code></td></tr>
2586 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAlive On</code></td></tr>
2587 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2588 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2589 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2591 <p>The Keep-Alive extension to HTTP/1.0 and the persistent
2592 connection feature of HTTP/1.1 provide long-lived HTTP sessions
2593 which allow multiple requests to be sent over the same TCP
2594 connection. In some cases this has been shown to result in an
2595 almost 50% speedup in latency times for HTML documents with
2596 many images. To enable Keep-Alive connections, set
2597 <code>KeepAlive On</code>.</p>
2599 <p>For HTTP/1.0 clients, Keep-Alive connections will only be
2600 used if they are specifically requested by a client. In
2601 addition, a Keep-Alive connection with an HTTP/1.0 client can
2602 only be used when the length of the content is known in
2603 advance. This implies that dynamic content such as CGI output,
2604 SSI pages, and server-generated directory listings will
2605 generally not use Keep-Alive connections to HTTP/1.0 clients.
2606 For HTTP/1.1 clients, persistent connections are the default
2607 unless otherwise specified. If the client requests it, chunked
2608 encoding will be used in order to send content of unknown
2609 length over persistent connections.</p>
2611 <p>When a client uses a Keep-Alive connection, it will be counted
2612 as a single "request" for the <code class="directive"><a href="../mod/mpm_common.html#maxconnectionsperchild">MaxConnectionsPerChild</a></code> directive, regardless
2613 of how many requests are sent using the connection.</p>
2617 <li><code class="directive"><a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></code></li>
2620 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2621 <div class="directive-section"><h2><a name="KeepAliveTimeout" id="KeepAliveTimeout">KeepAliveTimeout</a> <a name="keepalivetimeout" id="keepalivetimeout">Directive</a></h2>
2622 <table class="directive">
2623 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for subsequent
2624 requests on a persistent connection</td></tr>
2625 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAliveTimeout <var>num</var>[ms]</code></td></tr>
2626 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAliveTimeout 5</code></td></tr>
2627 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2628 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2629 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2631 <p>The number of seconds Apache httpd will wait for a subsequent
2632 request before closing the connection. By adding a postfix of ms the
2633 timeout can be also set in milliseconds. Once a request has been
2634 received, the timeout value specified by the
2635 <code class="directive"><a href="#timeout">Timeout</a></code> directive applies.</p>
2637 <p>Setting <code class="directive">KeepAliveTimeout</code> to a high value
2638 may cause performance problems in heavily loaded servers. The
2639 higher the timeout, the more server processes will be kept
2640 occupied waiting on connections with idle clients.</p>
2642 <p>If <code class="directive">KeepAliveTimeout</code> is <strong>not</strong>
2643 set for a name-based virtual host, the value of the first defined
2644 virtual host best matching the local IP and port will be used.</p>
2647 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2648 <div class="directive-section"><h2><a name="Limit" id="Limit"><Limit></a> <a name="limit" id="limit">Directive</a></h2>
2649 <table class="directive">
2650 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict enclosed access controls to only certain HTTP
2652 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Limit <var>method</var> [<var>method</var>] ... > ...
2653 </Limit></code></td></tr>
2654 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2655 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2656 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2657 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2659 <p>Access controls are normally effective for
2660 <strong>all</strong> access methods, and this is the usual
2661 desired behavior. <strong>In the general case, access control
2662 directives should not be placed within a
2663 <code class="directive"><Limit></code> section.</strong></p>
2665 <p>The purpose of the <code class="directive"><Limit></code>
2666 directive is to restrict the effect of the access controls to the
2667 nominated HTTP methods. For all other methods, the access
2668 restrictions that are enclosed in the <code class="directive"><Limit></code> bracket <strong>will have no
2669 effect</strong>. The following example applies the access control
2670 only to the methods <code>POST</code>, <code>PUT</code>, and
2671 <code>DELETE</code>, leaving all other methods unprotected:</p>
2673 <pre class="prettyprint lang-config"><Limit POST PUT DELETE>
2675 </Limit></pre>
2678 <p>The method names listed can be one or more of: <code>GET</code>,
2679 <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
2680 <code>CONNECT</code>, <code>OPTIONS</code>,
2681 <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
2682 <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
2683 <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
2684 case-sensitive.</strong> If <code>GET</code> is used, it will also
2685 restrict <code>HEAD</code> requests. The <code>TRACE</code> method
2686 cannot be limited (see <code class="directive"><a href="#traceenable">TraceEnable</a></code>).</p>
2688 <div class="warning">A <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section should always be
2689 used in preference to a <code class="directive"><Limit></code>
2690 section when restricting access, since a <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section provides protection
2691 against arbitrary methods.</div>
2693 <p>The <code class="directive"><Limit></code> and
2694 <code class="directive"><a href="#limitexcept"><LimitExcept></a></code>
2695 directives may be nested. In this case, each successive level of
2696 <code class="directive"><Limit></code> or <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> directives must
2697 further restrict the set of methods to which access controls apply.</p>
2699 <div class="warning">When using
2700 <code class="directive"><Limit></code> or
2701 <code class="directive"><LimitExcept></code> directives with
2702 the <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directive,
2703 note that the first <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code>
2704 to succeed authorizes the request, regardless of the presence of other
2705 <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directives.</div>
2707 <p>For example, given the following configuration, all users will
2708 be authorized for <code>POST</code> requests, and the
2709 <code>Require group editors</code> directive will be ignored
2712 <pre class="prettyprint lang-config"><LimitExcept GET>
2714 </LimitExcept>
2716 Require group editors
2717 </Limit></pre>
2721 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2722 <div class="directive-section"><h2><a name="LimitExcept" id="LimitExcept"><LimitExcept></a> <a name="limitexcept" id="limitexcept">Directive</a></h2>
2723 <table class="directive">
2724 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict access controls to all HTTP methods
2725 except the named ones</td></tr>
2726 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LimitExcept <var>method</var> [<var>method</var>] ... > ...
2727 </LimitExcept></code></td></tr>
2728 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2729 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2730 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2731 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2733 <p><code class="directive"><LimitExcept></code> and
2734 <code></LimitExcept></code> are used to enclose
2735 a group of access control directives which will then apply to any
2736 HTTP access method <strong>not</strong> listed in the arguments;
2737 i.e., it is the opposite of a <code class="directive"><a href="#limit"><Limit></a></code> section and can be used to control
2738 both standard and nonstandard/unrecognized methods. See the
2739 documentation for <code class="directive"><a href="#limit"><Limit></a></code> for more details.</p>
2743 <pre class="prettyprint lang-config"><LimitExcept POST GET>
2745 </LimitExcept></pre>
2750 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2751 <div class="directive-section"><h2><a name="LimitInternalRecursion" id="LimitInternalRecursion">LimitInternalRecursion</a> <a name="limitinternalrecursion" id="limitinternalrecursion">Directive</a></h2>
2752 <table class="directive">
2753 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine maximum number of internal redirects and nested
2754 subrequests</td></tr>
2755 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitInternalRecursion <var>number</var> [<var>number</var>]</code></td></tr>
2756 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitInternalRecursion 10</code></td></tr>
2757 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2758 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2759 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2761 <p>An internal redirect happens, for example, when using the <code class="directive"><a href="../mod/mod_actions.html#action">Action</a></code> directive, which internally
2762 redirects the original request to a CGI script. A subrequest is Apache httpd's
2763 mechanism to find out what would happen for some URI if it were requested.
2764 For example, <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> uses subrequests to look for the
2765 files listed in the <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
2768 <p><code class="directive">LimitInternalRecursion</code> prevents the server
2769 from crashing when entering an infinite loop of internal redirects or
2770 subrequests. Such loops are usually caused by misconfigurations.</p>
2772 <p>The directive stores two different limits, which are evaluated on
2773 per-request basis. The first <var>number</var> is the maximum number of
2774 internal redirects that may follow each other. The second <var>number</var>
2775 determines how deeply subrequests may be nested. If you specify only one
2776 <var>number</var>, it will be assigned to both limits.</p>
2778 <pre class="prettyprint lang-config">LimitInternalRecursion 5</pre>
2782 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2783 <div class="directive-section"><h2><a name="LimitRequestBody" id="LimitRequestBody">LimitRequestBody</a> <a name="limitrequestbody" id="limitrequestbody">Directive</a></h2>
2784 <table class="directive">
2785 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restricts the total size of the HTTP request body sent
2786 from the client</td></tr>
2787 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestBody <var>bytes</var></code></td></tr>
2788 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestBody 0</code></td></tr>
2789 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2790 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2791 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2792 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2794 <p>This directive specifies the number of <var>bytes</var> from 0
2795 (meaning unlimited) to 2147483647 (2GB) that are allowed in a
2796 request body. See the note below for the limited applicability
2797 to proxy requests.</p>
2799 <p>The <code class="directive">LimitRequestBody</code> directive allows
2800 the user to set a limit on the allowed size of an HTTP request
2801 message body within the context in which the directive is given
2802 (server, per-directory, per-file or per-location). If the client
2803 request exceeds that limit, the server will return an error
2804 response instead of servicing the request. The size of a normal
2805 request message body will vary greatly depending on the nature of
2806 the resource and the methods allowed on that resource. CGI scripts
2807 typically use the message body for retrieving form information.
2808 Implementations of the <code>PUT</code> method will require
2809 a value at least as large as any representation that the server
2810 wishes to accept for that resource.</p>
2812 <p>This directive gives the server administrator greater
2813 control over abnormal client request behavior, which may be
2814 useful for avoiding some forms of denial-of-service
2817 <p>If, for example, you are permitting file upload to a particular
2818 location and wish to limit the size of the uploaded file to 100K,
2819 you might use the following directive:</p>
2821 <pre class="prettyprint lang-config">LimitRequestBody 102400</pre>
2824 <div class="note"><p>For a full description of how this directive is interpreted by
2825 proxy requests, see the <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> documentation.</p>
2830 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2831 <div class="directive-section"><h2><a name="LimitRequestFields" id="LimitRequestFields">LimitRequestFields</a> <a name="limitrequestfields" id="limitrequestfields">Directive</a></h2>
2832 <table class="directive">
2833 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of HTTP request header fields that
2834 will be accepted from the client</td></tr>
2835 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFields <var>number</var></code></td></tr>
2836 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFields 100</code></td></tr>
2837 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2838 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2839 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2841 <p><var>Number</var> is an integer from 0 (meaning unlimited) to
2842 32767. The default value is defined by the compile-time
2843 constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
2846 <p>The <code class="directive">LimitRequestFields</code> directive allows
2847 the server administrator to modify the limit on the number of
2848 request header fields allowed in an HTTP request. A server needs
2849 this value to be larger than the number of fields that a normal
2850 client request might include. The number of request header fields
2851 used by a client rarely exceeds 20, but this may vary among
2852 different client implementations, often depending upon the extent
2853 to which a user has configured their browser to support detailed
2854 content negotiation. Optional HTTP extensions are often expressed
2855 using request header fields.</p>
2857 <p>This directive gives the server administrator greater
2858 control over abnormal client request behavior, which may be
2859 useful for avoiding some forms of denial-of-service attacks.
2860 The value should be increased if normal clients see an error
2861 response from the server that indicates too many fields were
2862 sent in the request.</p>
2866 <pre class="prettyprint lang-config">LimitRequestFields 50</pre>
2869 <div class="warning"><h3>Warning</h3>
2870 <p> When name-based virtual hosting is used, the value for this
2871 directive is taken from the default (first-listed) virtual host for the
2872 local IP and port combination.</p>
2877 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2878 <div class="directive-section"><h2><a name="LimitRequestFieldSize" id="LimitRequestFieldSize">LimitRequestFieldSize</a> <a name="limitrequestfieldsize" id="limitrequestfieldsize">Directive</a></h2>
2879 <table class="directive">
2880 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of the HTTP request header allowed from the
2882 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFieldSize <var>bytes</var></code></td></tr>
2883 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFieldSize 8190</code></td></tr>
2884 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2885 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2886 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2888 <p>This directive specifies the number of <var>bytes</var>
2889 that will be allowed in an HTTP request header.</p>
2891 <p>The <code class="directive">LimitRequestFieldSize</code> directive
2892 allows the server administrator to set the limit
2893 on the allowed size of an HTTP request header field. A server
2894 needs this value to be large enough to hold any one header field
2895 from a normal client request. The size of a normal request header
2896 field will vary greatly among different client implementations,
2897 often depending upon the extent to which a user has configured
2898 their browser to support detailed content negotiation. SPNEGO
2899 authentication headers can be up to 12392 bytes.</p>
2901 <p>This directive gives the server administrator greater
2902 control over abnormal client request behavior, which may be
2903 useful for avoiding some forms of denial-of-service attacks.</p>
2907 <pre class="prettyprint lang-config">LimitRequestFieldSize 4094</pre>
2910 <div class="note">Under normal conditions, the value should not be changed from
2913 <div class="warning"><h3>Warning</h3>
2914 <p> When name-based virtual hosting is used, the value for this
2915 directive is taken from the default (first-listed) virtual host best
2916 matching the current IP address and port combination.</p>
2920 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2921 <div class="directive-section"><h2><a name="LimitRequestLine" id="LimitRequestLine">LimitRequestLine</a> <a name="limitrequestline" id="limitrequestline">Directive</a></h2>
2922 <table class="directive">
2923 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limit the size of the HTTP request line that will be accepted
2924 from the client</td></tr>
2925 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestLine <var>bytes</var></code></td></tr>
2926 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestLine 8190</code></td></tr>
2927 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2928 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2929 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2931 <p>This directive sets the number of <var>bytes</var> that will be
2932 allowed on the HTTP request-line.</p>
2934 <p>The <code class="directive">LimitRequestLine</code> directive allows
2935 the server administrator to set the limit on the allowed size
2936 of a client's HTTP request-line. Since the request-line consists of the
2937 HTTP method, URI, and protocol version, the
2938 <code class="directive">LimitRequestLine</code> directive places a
2939 restriction on the length of a request-URI allowed for a request
2940 on the server. A server needs this value to be large enough to
2941 hold any of its resource names, including any information that
2942 might be passed in the query part of a <code>GET</code> request.</p>
2944 <p>This directive gives the server administrator greater
2945 control over abnormal client request behavior, which may be
2946 useful for avoiding some forms of denial-of-service attacks.</p>
2950 <pre class="prettyprint lang-config">LimitRequestLine 4094</pre>
2953 <div class="note">Under normal conditions, the value should not be changed from
2956 <div class="warning"><h3>Warning</h3>
2957 <p> When name-based virtual hosting is used, the value for this
2958 directive is taken from the default (first-listed) virtual host best
2959 matching the current IP address and port combination.</p>
2964 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2965 <div class="directive-section"><h2><a name="LimitXMLRequestBody" id="LimitXMLRequestBody">LimitXMLRequestBody</a> <a name="limitxmlrequestbody" id="limitxmlrequestbody">Directive</a></h2>
2966 <table class="directive">
2967 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of an XML-based request body</td></tr>
2968 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitXMLRequestBody <var>bytes</var></code></td></tr>
2969 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitXMLRequestBody 1000000</code></td></tr>
2970 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2971 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2972 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2973 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2975 <p>Limit (in bytes) on maximum size of an XML-based request
2976 body. A value of <code>0</code> will disable any checking.</p>
2980 <pre class="prettyprint lang-config">LimitXMLRequestBody 0</pre>
2985 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2986 <div class="directive-section"><h2><a name="Location" id="Location"><Location></a> <a name="location" id="location">Directive</a></h2>
2987 <table class="directive">
2988 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to matching
2990 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Location
2991 <var>URL-path</var>|<var>URL</var>> ... </Location></code></td></tr>
2992 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2993 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2994 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2996 <p>The <code class="directive"><Location></code> directive
2997 limits the scope of the enclosed directives by URL. It is similar to the
2998 <code class="directive"><a href="#directory"><Directory></a></code>
2999 directive, and starts a subsection which is terminated with a
3000 <code></Location></code> directive. <code class="directive"><Location></code> sections are processed in the
3001 order they appear in the configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
3002 <code>.htaccess</code> files are read, and after the <code class="directive"><a href="#files"><Files></a></code> sections.</p>
3004 <p><code class="directive"><Location></code> sections operate
3005 completely outside the filesystem. This has several consequences.
3006 Most importantly, <code class="directive"><Location></code>
3007 directives should not be used to control access to filesystem
3008 locations. Since several different URLs may map to the same
3009 filesystem location, such access controls may by circumvented.</p>
3011 <p>The enclosed directives will be applied to the request if the path component
3012 of the URL meets <em>any</em> of the following criteria:
3015 <li>The specified location matches exactly the path component of the URL.
3017 <li>The specified location, which ends in a forward slash, is a prefix
3018 of the path component of the URL (treated as a context root).
3020 <li>The specified location, with the addition of a trailing slash, is a
3021 prefix of the path component of the URL (also treated as a context root).
3025 In the example below, where no trailing slash is used, requests to
3026 /private1, /private1/ and /private1/file.txt will have the enclosed
3027 directives applied, but /private1other would not.
3029 <pre class="prettyprint lang-config"><Location "/private1">
3031 </Location></pre>
3034 In the example below, where a trailing slash is used, requests to
3035 /private2/ and /private2/file.txt will have the enclosed
3036 directives applied, but /private2 and /private2other would not.
3038 <pre class="prettyprint lang-config"><Location "/private2<em>/</em>">
3040 </Location></pre>
3043 <div class="note"><h3>When to use <code class="directive"><Location></code></h3>
3045 <p>Use <code class="directive"><Location></code> to apply
3046 directives to content that lives outside the filesystem. For
3047 content that lives in the filesystem, use <code class="directive"><a href="#directory"><Directory></a></code> and <code class="directive"><a href="#files"><Files></a></code>. An exception is
3048 <code><Location "/"></code>, which is an easy way to
3049 apply a configuration to the entire server.</p>
3052 <p>For all origin (non-proxy) requests, the URL to be matched is a
3053 URL-path of the form <code>/path/</code>. <em>No scheme, hostname,
3054 port, or query string may be included.</em> For proxy requests, the
3055 URL to be matched is of the form
3056 <code>scheme://servername/path</code>, and you must include the
3059 <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
3060 any single character, and <code>*</code> matches any sequences of
3061 characters. Neither wildcard character matches a / in the URL-path.</p>
3063 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
3064 can also be used, with the addition of the <code>~</code>
3065 character. For example:</p>
3067 <pre class="prettyprint lang-config"><Location ~ "/(extra|special)/data">
3069 </Location></pre>
3072 <p>would match URLs that contained the substring <code>/extra/data</code>
3073 or <code>/special/data</code>. The directive <code class="directive"><a href="#locationmatch"><LocationMatch></a></code> behaves
3074 identical to the regex version of <code class="directive"><Location></code>, and is preferred, for the
3075 simple reason that <code>~</code> is hard to distinguish from
3076 <code>-</code> in many fonts.</p>
3078 <p>The <code class="directive"><Location></code>
3079 functionality is especially useful when combined with the
3080 <code class="directive"><a href="#sethandler">SetHandler</a></code>
3081 directive. For example, to enable status requests but allow them
3082 only from browsers at <code>example.com</code>, you might use:</p>
3084 <pre class="prettyprint lang-config"><Location "/status">
3085 SetHandler server-status
3086 Require host example.com
3087 </Location></pre>
3090 <div class="note"><h3>Note about / (slash)</h3>
3091 <p>The slash character has special meaning depending on where in a
3092 URL it appears. People may be used to its behavior in the filesystem
3093 where multiple adjacent slashes are frequently collapsed to a single
3094 slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
3095 <code>/home/foo</code>). In URL-space this is not necessarily true.
3096 The <code class="directive"><a href="#locationmatch"><LocationMatch></a></code>
3097 directive and the regex version of <code class="directive"><Location></code> require you to explicitly specify multiple
3098 slashes if that is your intention.</p>
3100 <p>For example, <code><LocationMatch "^/abc"></code> would match
3101 the request URL <code>/abc</code> but not the request URL <code>
3102 //abc</code>. The (non-regex) <code class="directive"><Location></code> directive behaves similarly when used for
3103 proxy requests. But when (non-regex) <code class="directive"><Location></code> is used for non-proxy requests it will
3104 implicitly match multiple slashes with a single slash. For example,
3105 if you specify <code><Location "/abc/def"></code> and the
3106 request is to <code>/abc//def</code> then it will match.</p>
3111 <li><a href="../sections.html">How <Directory>, <Location>
3112 and <Files> sections work</a> for an explanation of how these
3113 different sections are combined when a request is received.</li>
3114 <li><code class="directive"><a href="#locationmatch">LocationMatch</a></code></li>
3117 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3118 <div class="directive-section"><h2><a name="LocationMatch" id="LocationMatch"><LocationMatch></a> <a name="locationmatch" id="locationmatch">Directive</a></h2>
3119 <table class="directive">
3120 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to regular-expression
3121 matching URLs</td></tr>
3122 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LocationMatch
3123 <var>regex</var>> ... </LocationMatch></code></td></tr>
3124 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3125 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3126 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3128 <p>The <code class="directive"><LocationMatch></code> directive
3129 limits the scope of the enclosed directives by URL, in an identical manner
3130 to <code class="directive"><a href="#location"><Location></a></code>. However,
3131 it takes a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
3132 as an argument instead of a simple string. For example:</p>
3134 <pre class="prettyprint lang-config"><LocationMatch "/(extra|special)/data">
3136 </LocationMatch></pre>
3139 <p>would match URLs that contained the substring <code>/extra/data</code>
3140 or <code>/special/data</code>.</p>
3142 <div class="note"><p>If the intent is that a URL <strong>starts with</strong>
3143 <code>/extra/data</code>, rather than merely
3144 <strong>contains</strong> <code>/extra/data</code>, prefix the
3145 regular expression with a <code>^</code> to require this.</p>
3147 <pre class="prettyprint lang-config"><LocationMatch "^/(extra|special)/data"></pre>
3151 <p>From 2.4.8 onwards, named groups and backreferences are captured and
3152 written to the environment with the corresponding name prefixed with
3153 "MATCH_" and in upper case. This allows elements of URLs to be referenced
3154 from within <a href="../expr.html">expressions</a> and modules like
3155 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
3156 (unnamed) backreferences are ignored. Use named groups instead.</p>
3158 <pre class="prettyprint lang-config"><LocationMatch "^/combined/(?<sitename>[^/]+)">
3159 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
3160 </LocationMatch></pre>
3165 <li><a href="../sections.html">How <Directory>, <Location>
3166 and <Files> sections work</a> for an explanation of how these
3167 different sections are combined when a request is received</li>
3170 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3171 <div class="directive-section"><h2><a name="LogLevel" id="LogLevel">LogLevel</a> <a name="loglevel" id="loglevel">Directive</a></h2>
3172 <table class="directive">
3173 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Controls the verbosity of the ErrorLog</td></tr>
3174 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel [<var>module</var>:]<var>level</var>
3175 [<var>module</var>:<var>level</var>] ...
3177 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LogLevel warn</code></td></tr>
3178 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3179 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3180 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3181 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Per-module and per-directory configuration is available in
3182 Apache HTTP Server 2.3.6 and later</td></tr>
3184 <p><code class="directive">LogLevel</code> adjusts the verbosity of the
3185 messages recorded in the error logs (see <code class="directive"><a href="#errorlog">ErrorLog</a></code> directive). The following
3186 <var>level</var>s are available, in order of decreasing
3189 <table class="bordered">
3192 <th><strong>Level</strong> </th>
3194 <th><strong>Description</strong> </th>
3196 <th><strong>Example</strong> </th>
3200 <td><code>emerg</code> </td>
3202 <td>Emergencies - system is unusable.</td>
3204 <td>"Child cannot open lock file. Exiting"</td>
3208 <td><code>alert</code> </td>
3210 <td>Action must be taken immediately.</td>
3212 <td>"getpwuid: couldn't determine user name from uid"</td>
3216 <td><code>crit</code> </td>
3218 <td>Critical Conditions.</td>
3220 <td>"socket: Failed to get a socket, exiting child"</td>
3224 <td><code>error</code> </td>
3226 <td>Error conditions.</td>
3228 <td>"Premature end of script headers"</td>
3232 <td><code>warn</code> </td>
3234 <td>Warning conditions.</td>
3236 <td>"child process 1234 did not exit, sending another
3241 <td><code>notice</code> </td>
3243 <td>Normal but significant condition.</td>
3245 <td>"httpd: caught SIGBUS, attempting to dump core in
3250 <td><code>info</code> </td>
3252 <td>Informational.</td>
3254 <td>"Server seems busy, (you may need to increase
3255 StartServers, or Min/MaxSpareServers)..."</td>
3259 <td><code>debug</code> </td>
3261 <td>Debug-level messages</td>
3263 <td>"Opening config file ..."</td>
3266 <td><code>trace1</code> </td>
3268 <td>Trace messages</td>
3270 <td>"proxy: FTP: control connection complete"</td>
3273 <td><code>trace2</code> </td>
3275 <td>Trace messages</td>
3277 <td>"proxy: CONNECT: sending the CONNECT request to the remote proxy"</td>
3280 <td><code>trace3</code> </td>
3282 <td>Trace messages</td>
3284 <td>"openssl: Handshake: start"</td>
3287 <td><code>trace4</code> </td>
3289 <td>Trace messages</td>
3291 <td>"read from buffered SSL brigade, mode 0, 17 bytes"</td>
3294 <td><code>trace5</code> </td>
3296 <td>Trace messages</td>
3298 <td>"map lookup FAILED: map=rewritemap key=keyname"</td>
3301 <td><code>trace6</code> </td>
3303 <td>Trace messages</td>
3305 <td>"cache lookup FAILED, forcing new map lookup"</td>
3308 <td><code>trace7</code> </td>
3310 <td>Trace messages, dumping large amounts of data</td>
3312 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
3315 <td><code>trace8</code> </td>
3317 <td>Trace messages, dumping large amounts of data</td>
3319 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
3323 <p>When a particular level is specified, messages from all
3324 other levels of higher significance will be reported as well.
3325 <em>E.g.</em>, when <code>LogLevel info</code> is specified,
3326 then messages with log levels of <code>notice</code> and
3327 <code>warn</code> will also be posted.</p>
3329 <p>Using a level of at least <code>crit</code> is
3334 <pre class="prettyprint lang-config">LogLevel notice</pre>
3337 <div class="note"><h3>Note</h3>
3338 <p>When logging to a regular file, messages of the level
3339 <code>notice</code> cannot be suppressed and thus are always
3340 logged. However, this doesn't apply when logging is done
3341 using <code>syslog</code>.</p>
3344 <p>Specifying a level without a module name will reset the level
3345 for all modules to that level. Specifying a level with a module
3346 name will set the level for that module only. It is possible to
3347 use the module source file name, the module identifier, or the
3348 module identifier with the trailing <code>_module</code> omitted
3349 as module specification. This means the following three specifications
3352 <pre class="prettyprint lang-config">LogLevel info ssl:warn
3353 LogLevel info mod_ssl.c:warn
3354 LogLevel info ssl_module:warn</pre>
3357 <p>It is also possible to change the level per directory:</p>
3359 <pre class="prettyprint lang-config">LogLevel info
3360 <Directory "/usr/local/apache/htdocs/app">
3362 </Directory></pre>
3366 Per directory loglevel configuration only affects messages that are
3367 logged after the request has been parsed and that are associated with
3368 the request. Log messages which are associated with the server or
3369 the connection are not affected. The latter can be influenced by the
3370 <code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code> directive,
3376 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
3377 <li><code class="directive"><a href="#errorlogformat">ErrorLogFormat</a></code></li>
3378 <li><code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code></li>
3379 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
3382 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3383 <div class="directive-section"><h2><a name="LogLevelOverride" id="LogLevelOverride">LogLevelOverride</a> <a name="logleveloverride" id="logleveloverride">Directive</a></h2>
3384 <table class="directive">
3385 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Override the verbosity of the ErrorLog for certain clients</td></tr>
3386 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel <var>ipaddress</var>[/<var>prefixlen</var>]
3387 [<var>module</var>:]<var>level</var> [<var>module</var>:<var>level</var>] ...
3389 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>unset</code></td></tr>
3390 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3391 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3392 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3393 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.5.0 and later</td></tr>
3395 <p><code class="directive">LogLevelOverride</code> adjusts the
3396 <code class="directive"><a href="#loglevel">LogLevel</a></code> for requests coming from
3397 certain client IP addresses.
3398 This allows to enable verbose logging only for certain test clients.
3399 The IP address is checked at a very early state in the connection
3400 processing. Therefore, <code class="directive">LogLevelOverride</code> allows to
3401 change the log level for things like the SSL handshake which happen before
3402 a <code class="directive"><a href="#loglevel">LogLevel</a></code> directive in an
3403 <code class="directive"><a href="#if"><If></a></code> container would
3406 <p><code class="directive">LogLevelOverride</code> accepts either a single
3407 IP-address or a CIDR IP-address/len subnet specification.
3408 For the syntax of the loglevel specification, see the
3409 <code class="directive"><a href="#loglevel">LogLevel</a></code> directive.</p>
3411 <p>For requests that match a <code class="directive">LogLevelOverride</code>
3412 directive, per-directory specifications of
3413 <code class="directive"><a href="#loglevel">LogLevel</a></code> are ignored.</p>
3417 <pre class="prettyprint lang-config"> LogLevelOverride 192.0.2.0/24 ssl:trace6
3418 LogLevelOverride 192.0.2.7 ssl:trace8</pre>
3422 <code class="directive">LogLevelOverride</code> only affects
3423 log messages that are associated with the request or the connection.
3424 Log messages which are associated with the server are not affected.
3430 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
3433 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3434 <div class="directive-section"><h2><a name="MaxKeepAliveRequests" id="MaxKeepAliveRequests">MaxKeepAliveRequests</a> <a name="maxkeepaliverequests" id="maxkeepaliverequests">Directive</a></h2>
3435 <table class="directive">
3436 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of requests allowed on a persistent
3437 connection</td></tr>
3438 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxKeepAliveRequests <var>number</var></code></td></tr>
3439 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxKeepAliveRequests 100</code></td></tr>
3440 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3441 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3442 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3444 <p>The <code class="directive">MaxKeepAliveRequests</code> directive
3445 limits the number of requests allowed per connection when
3446 <code class="directive"><a href="#keepalive">KeepAlive</a></code> is on. If it is
3447 set to <code>0</code>, unlimited requests will be allowed. We
3448 recommend that this setting be kept to a high value for maximum
3449 server performance.</p>
3453 <pre class="prettyprint lang-config">MaxKeepAliveRequests 500</pre>
3457 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3458 <div class="directive-section"><h2><a name="MaxRangeOverlaps" id="MaxRangeOverlaps">MaxRangeOverlaps</a> <a name="maxrangeoverlaps" id="maxrangeoverlaps">Directive</a></h2>
3459 <table class="directive">
3460 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of overlapping ranges (eg: <code>100-200,150-300</code>) allowed before returning the complete
3462 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxRangeOverlaps default | unlimited | none | <var>number-of-ranges</var></code></td></tr>
3463 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeOverlaps 20</code></td></tr>
3464 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3465 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3466 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3467 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3469 <p>The <code class="directive">MaxRangeOverlaps</code> directive
3470 limits the number of overlapping HTTP ranges the server is willing to
3471 return to the client. If more overlapping ranges than permitted are requested,
3472 the complete resource is returned instead.</p>
3475 <dt><strong>default</strong></dt>
3476 <dd>Limits the number of overlapping ranges to a compile-time default of 20.</dd>
3478 <dt><strong>none</strong></dt>
3479 <dd>No overlapping Range headers are allowed.</dd>
3481 <dt><strong>unlimited</strong></dt>
3482 <dd>The server does not limit the number of overlapping ranges it is
3483 willing to satisfy.</dd>
3485 <dt><var>number-of-ranges</var></dt>
3486 <dd>A positive number representing the maximum number of overlapping ranges the
3487 server is willing to satisfy.</dd>
3491 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3492 <div class="directive-section"><h2><a name="MaxRangeReversals" id="MaxRangeReversals">MaxRangeReversals</a> <a name="maxrangereversals" id="maxrangereversals">Directive</a></h2>
3493 <table class="directive">
3494 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of range reversals (eg: <code>100-200,50-70</code>) allowed before returning the complete
3496 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxRangeReversals default | unlimited | none | <var>number-of-ranges</var></code></td></tr>
3497 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeReversals 20</code></td></tr>
3498 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3499 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3500 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3501 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3503 <p>The <code class="directive">MaxRangeReversals</code> directive
3504 limits the number of HTTP Range reversals the server is willing to
3505 return to the client. If more ranges reversals than permitted are requested,
3506 the complete resource is returned instead.</p>
3509 <dt><strong>default</strong></dt>
3510 <dd>Limits the number of range reversals to a compile-time default of 20.</dd>
3512 <dt><strong>none</strong></dt>
3513 <dd>No Range reversals headers are allowed.</dd>
3515 <dt><strong>unlimited</strong></dt>
3516 <dd>The server does not limit the number of range reversals it is
3517 willing to satisfy.</dd>
3519 <dt><var>number-of-ranges</var></dt>
3520 <dd>A positive number representing the maximum number of range reversals the
3521 server is willing to satisfy.</dd>
3525 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3526 <div class="directive-section"><h2><a name="MaxRanges" id="MaxRanges">MaxRanges</a> <a name="maxranges" id="maxranges">Directive</a></h2>
3527 <table class="directive">
3528 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of ranges allowed before returning the complete
3530 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxRanges default | unlimited | none | <var>number-of-ranges</var></code></td></tr>
3531 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRanges 200</code></td></tr>
3532 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3533 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3534 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3535 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3537 <p>The <code class="directive">MaxRanges</code> directive
3538 limits the number of HTTP ranges the server is willing to
3539 return to the client. If more ranges than permitted are requested,
3540 the complete resource is returned instead.</p>
3543 <dt><strong>default</strong></dt>
3544 <dd>Limits the number of ranges to a compile-time default of 200.</dd>
3546 <dt><strong>none</strong></dt>
3547 <dd>Range headers are ignored.</dd>
3549 <dt><strong>unlimited</strong></dt>
3550 <dd>The server does not limit the number of ranges it is
3551 willing to satisfy.</dd>
3553 <dt><var>number-of-ranges</var></dt>
3554 <dd>A positive number representing the maximum number of ranges the
3555 server is willing to satisfy.</dd>
3559 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3560 <div class="directive-section"><h2><a name="MergeTrailers" id="MergeTrailers">MergeTrailers</a> <a name="mergetrailers" id="mergetrailers">Directive</a></h2>
3561 <table class="directive">
3562 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines whether trailers are merged into headers</td></tr>
3563 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MergeTrailers [on|off]</code></td></tr>
3564 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MergeTrailers off</code></td></tr>
3565 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3566 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3567 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3568 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.4.11 and later</td></tr>
3570 <p>This directive controls whether HTTP trailers are copied into the
3571 internal representation of HTTP headers. This merging occurs when the
3572 request body has been completely consumed, long after most header
3573 processing would have a chance to examine or modify request headers.</p>
3574 <p>This option is provided for compatibility with releases prior to 2.4.11,
3575 where trailers were always merged.</p>
3578 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3579 <div class="directive-section"><h2><a name="Mutex" id="Mutex">Mutex</a> <a name="mutex" id="mutex">Directive</a></h2>
3580 <table class="directive">
3581 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures mutex mechanism and lock file directory for all
3582 or specified mutexes</td></tr>
3583 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Mutex <var>mechanism</var> [default|<var>mutex-name</var>] ... [OmitPID]</code></td></tr>
3584 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Mutex default</code></td></tr>
3585 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3586 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3587 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3588 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.4 and later</td></tr>
3590 <p>The <code class="directive">Mutex</code> directive sets the mechanism,
3591 and optionally the lock file location, that httpd and modules use
3592 to serialize access to resources. Specify <code>default</code> as
3593 the second argument to change the settings for all mutexes; specify
3594 a mutex name (see table below) as the second argument to override
3595 defaults only for that mutex.</p>
3597 <p>The <code class="directive">Mutex</code> directive is typically used in
3598 the following exceptional situations:</p>
3601 <li>change the mutex mechanism when the default mechanism selected
3602 by <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> has a functional or performance
3605 <li>change the directory used by file-based mutexes when the
3606 default directory does not support locking</li>
3609 <div class="note"><h3>Supported modules</h3>
3610 <p>This directive only configures mutexes which have been registered
3611 with the core server using the <code>ap_mutex_register()</code> API.
3612 All modules bundled with httpd support the <code class="directive">Mutex</code>
3613 directive, but third-party modules may not. Consult the documentation
3614 of the third-party module, which must indicate the mutex name(s) which
3615 can be configured if this directive is supported.</p>
3618 <p>The following mutex <em>mechanisms</em> are available:</p>
3620 <li><code>default | yes</code>
3621 <p>This selects the default locking implementation, as determined by
3622 <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a>. The default locking implementation can
3623 be displayed by running <code class="program"><a href="../programs/httpd.html">httpd</a></code> with the
3624 <code>-V</code> option.</p></li>
3626 <li><code>none | no</code>
3627 <p>This effectively disables the mutex, and is only allowed for a
3628 mutex if the module indicates that it is a valid choice. Consult the
3629 module documentation for more information.</p></li>
3631 <li><code>posixsem</code>
3632 <p>This is a mutex variant based on a Posix semaphore.</p>
3634 <div class="warning"><h3>Warning</h3>
3635 <p>The semaphore ownership is not recovered if a thread in the process
3636 holding the mutex segfaults, resulting in a hang of the web server.</p>
3640 <li><code>sysvsem</code>
3641 <p>This is a mutex variant based on a SystemV IPC semaphore.</p>
3643 <div class="warning"><h3>Warning</h3>
3644 <p>It is possible to "leak" SysV semaphores if processes crash
3645 before the semaphore is removed.</p>
3648 <div class="warning"><h3>Security</h3>
3649 <p>The semaphore API allows for a denial of service attack by any
3650 CGIs running under the same uid as the webserver (<em>i.e.</em>,
3651 all CGIs, unless you use something like <code class="program"><a href="../programs/suexec.html">suexec</a></code>
3652 or <code>cgiwrapper</code>).</p>
3656 <li><code>sem</code>
3657 <p>This selects the "best" available semaphore implementation, choosing
3658 between Posix and SystemV IPC semaphores, in that order.</p></li>
3660 <li><code>pthread</code>
3661 <p>This is a mutex variant based on cross-process Posix thread
3664 <div class="warning"><h3>Warning</h3>
3665 <p>On most systems, if a child process terminates abnormally while
3666 holding a mutex that uses this implementation, the server will deadlock
3667 and stop responding to requests. When this occurs, the server will
3668 require a manual restart to recover.</p>
3669 <p>Solaris and Linux are notable exceptions as they provide a mechanism which
3670 usually allows the mutex to be recovered after a child process
3671 terminates abnormally while holding a mutex.</p>
3672 <p>If your system is POSIX compliant or if it implements the
3673 <code>pthread_mutexattr_setrobust_np()</code> function, you may be able
3674 to use the <code>pthread</code> option safely.</p>
3678 <li><code>fcntl:/path/to/mutex</code>
3679 <p>This is a mutex variant where a physical (lock-)file and the
3680 <code>fcntl()</code> function are used as the mutex.</p>
3682 <div class="warning"><h3>Warning</h3>
3683 <p>When multiple mutexes based on this mechanism are used within
3684 multi-threaded, multi-process environments, deadlock errors (EDEADLK)
3685 can be reported for valid mutex operations if <code>fcntl()</code>
3686 is not thread-aware, such as on Solaris.</p>
3690 <li><code>flock:/path/to/mutex</code>
3691 <p>This is similar to the <code>fcntl:/path/to/mutex</code> method
3692 with the exception that the <code>flock()</code> function is used to
3693 provide file locking.</p></li>
3695 <li><code>file:/path/to/mutex</code>
3696 <p>This selects the "best" available file locking implementation,
3697 choosing between <code>fcntl</code> and <code>flock</code>, in that
3701 <p>Most mechanisms are only available on selected platforms, where the
3702 underlying platform and <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> support it. Mechanisms
3703 which aren't available on all platforms are <em>posixsem</em>,
3704 <em>sysvsem</em>, <em>sem</em>, <em>pthread</em>, <em>fcntl</em>,
3705 <em>flock</em>, and <em>file</em>.</p>
3707 <p>With the file-based mechanisms <em>fcntl</em> and <em>flock</em>,
3708 the path, if provided, is a directory where the lock file will be created.
3709 The default directory is httpd's run-time file directory,
3710 <code class="directive"><a href="#defaultruntimedir">DefaultRuntimeDir</a></code>. If a relative
3711 path is provided, it is relative to
3712 <code class="directive"><a href="#defaultruntimedir">DefaultRuntimeDir</a></code>. Always use a local
3713 disk filesystem for <code>/path/to/mutex</code> and never a directory residing
3714 on a NFS- or AFS-filesystem. The basename of the file will be the mutex
3715 type, an optional instance string provided by the module, and unless the
3716 <code>OmitPID</code> keyword is specified, the process id of the httpd
3717 parent process will be appended to make the file name unique, avoiding
3718 conflicts when multiple httpd instances share a lock file directory. For
3719 example, if the mutex name is <code>mpm-accept</code> and the lock file
3720 directory is <code>/var/httpd/locks</code>, the lock file name for the
3721 httpd instance with parent process id 12345 would be
3722 <code>/var/httpd/locks/mpm-accept.12345</code>.</p>
3724 <div class="warning"><h3>Security</h3>
3725 <p>It is best to <em>avoid</em> putting mutex files in a world-writable
3726 directory such as <code>/var/tmp</code> because someone could create
3727 a denial of service attack and prevent the server from starting by
3728 creating a lockfile with the same name as the one the server will try
3732 <p>The following table documents the names of mutexes used by httpd
3733 and bundled modules.</p>
3735 <table class="bordered"><tr class="header">
3738 <th>Protected resource</th>
3741 <td><code>mpm-accept</code></td>
3742 <td><code class="module"><a href="../mod/prefork.html">prefork</a></code> and <code class="module"><a href="../mod/worker.html">worker</a></code> MPMs</td>
3743 <td>incoming connections, to avoid the thundering herd problem;
3744 for more information, refer to the
3745 <a href="../misc/perf-tuning.html">performance tuning</a>
3749 <td><code>authdigest-client</code></td>
3750 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3751 <td>client list in shared memory</td>
3754 <td><code>authdigest-opaque</code></td>
3755 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3756 <td>counter in shared memory</td>
3759 <td><code>ldap-cache</code></td>
3760 <td><code class="module"><a href="../mod/mod_ldap.html">mod_ldap</a></code></td>
3761 <td>LDAP result cache</td>
3764 <td><code>rewrite-map</code></td>
3765 <td><code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code></td>
3766 <td>communication with external mapping programs, to avoid
3767 intermixed I/O from multiple requests</td>
3770 <td><code>ssl-cache</code></td>
3771 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3772 <td>SSL session cache</td>
3775 <td><code>ssl-stapling</code></td>
3776 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3777 <td>OCSP stapling response cache</td>
3780 <td><code>watchdog-callback</code></td>
3781 <td><code class="module"><a href="../mod/mod_watchdog.html">mod_watchdog</a></code></td>
3782 <td>callback function of a particular client module</td>
3786 <p>The <code>OmitPID</code> keyword suppresses the addition of the httpd
3787 parent process id from the lock file name.</p>
3789 <p>In the following example, the mutex mechanism for the MPM accept
3790 mutex will be changed from the compiled-in default to <code>fcntl</code>,
3791 with the associated lock file created in directory
3792 <code>/var/httpd/locks</code>. The mutex mechanism for all other mutexes
3793 will be changed from the compiled-in default to <code>sysvsem</code>.</p>
3795 <pre class="prettyprint lang-config">Mutex sysvsem default
3796 Mutex fcntl:/var/httpd/locks mpm-accept</pre>
3800 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3801 <div class="directive-section"><h2><a name="NameVirtualHost" id="NameVirtualHost">NameVirtualHost</a> <a name="namevirtualhost" id="namevirtualhost">Directive</a></h2>
3802 <table class="directive">
3803 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>DEPRECATED: Designates an IP address for name-virtual
3805 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NameVirtualHost <var>addr</var>[:<var>port</var>]</code></td></tr>
3806 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3807 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3808 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3811 <p>Prior to 2.3.11, <code class="directive">NameVirtualHost</code> was required
3812 to instruct the server that a particular IP address and port combination
3813 was usable as a name-based virtual host. In 2.3.11 and later,
3814 any time an IP address and port combination is used in multiple virtual
3815 hosts, name-based virtual hosting is automatically enabled for that address.</p>
3817 <p>This directive currently has no effect.</p>
3821 <li><a href="../vhosts/">Virtual Hosts
3822 documentation</a></li>
3825 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3826 <div class="directive-section"><h2><a name="Options" id="Options">Options</a> <a name="options" id="options">Directive</a></h2>
3827 <table class="directive">
3828 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures what features are available in a particular
3830 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Options
3831 [+|-]<var>option</var> [[+|-]<var>option</var>] ...</code></td></tr>
3832 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Options FollowSymlinks</code></td></tr>
3833 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3834 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
3835 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3836 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3837 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>The default was changed from All to FollowSymlinks in 2.3.11</td></tr>
3839 <p>The <code class="directive">Options</code> directive controls which
3840 server features are available in a particular directory.</p>
3842 <p><var>option</var> can be set to <code>None</code>, in which
3843 case none of the extra features are enabled, or one or more of
3847 <dt><code>All</code></dt>
3849 <dd>All options except for <code>MultiViews</code>.</dd>
3851 <dt><code>ExecCGI</code></dt>
3854 Execution of CGI scripts using <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>
3857 <dt><code>FollowSymLinks</code></dt>
3860 The server will follow symbolic links in this directory. This is
3861 the default setting.
3863 <p>Even though the server follows the symlink it does <em>not</em>
3864 change the pathname used to match against <code class="directive"><a href="#directory"><Directory></a></code> sections.</p>
3866 <p>The <code>FollowSymLinks</code> and
3867 <code>SymLinksIfOwnerMatch</code> <code class="directive"><a href="#options">Options</a></code> work only in <code class="directive"><a href="#directory"><Directory></a></code> sections or
3868 <code>.htaccess</code> files.</p>
3870 <p>Omitting this option should not be considered a security restriction,
3871 since symlink testing is subject to race conditions that make it
3875 <dt><code>Includes</code></dt>
3878 Server-side includes provided by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
3881 <dt><code>IncludesNOEXEC</code></dt>
3885 Server-side includes are permitted, but the <code>#exec
3886 cmd</code> and <code>#exec cgi</code> are disabled. It is still
3887 possible to <code>#include virtual</code> CGI scripts from
3888 <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>ed
3891 <dt><code>Indexes</code></dt>
3894 If a URL which maps to a directory is requested and there
3895 is no <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
3896 (<em>e.g.</em>, <code>index.html</code>) in that directory, then
3897 <code class="module"><a href="../mod/mod_autoindex.html">mod_autoindex</a></code> will return a formatted listing
3898 of the directory.</dd>
3900 <dt><code>MultiViews</code></dt>
3903 <a href="../content-negotiation.html">Content negotiated</a>
3904 "MultiViews" are allowed using
3905 <code class="module"><a href="../mod/mod_negotiation.html">mod_negotiation</a></code>.
3906 <div class="note"><h3>Note</h3> <p>This option gets ignored if set
3907 anywhere other than <code class="directive"><a href="#directory"><Directory></a></code>, as <code class="module"><a href="../mod/mod_negotiation.html">mod_negotiation</a></code>
3908 needs real resources to compare against and evaluate from.</p></div>
3911 <dt><code>SymLinksIfOwnerMatch</code></dt>
3913 <dd>The server will only follow symbolic links for which the
3914 target file or directory is owned by the same user id as the
3917 <div class="note"><h3>Note</h3>
3918 <p>The <code>FollowSymLinks</code> and
3919 <code>SymLinksIfOwnerMatch</code> <code class="directive"><a href="#options">Options</a></code> work only in <code class="directive"><a href="#directory"><Directory></a></code> sections or
3920 <code>.htaccess</code> files.</p>
3922 <p>This option should not be considered a security restriction,
3923 since symlink testing is subject to race conditions that make it
3928 <p>Normally, if multiple <code class="directive">Options</code> could
3929 apply to a directory, then the most specific one is used and
3930 others are ignored; the options are not merged. (See <a href="../sections.html#merging">how sections are merged</a>.)
3931 However if <em>all</em> the options on the
3932 <code class="directive">Options</code> directive are preceded by a
3933 <code>+</code> or <code>-</code> symbol, the options are
3934 merged. Any options preceded by a <code>+</code> are added to the
3935 options currently in force, and any options preceded by a
3936 <code>-</code> are removed from the options currently in
3939 <div class="note"><h3>Note</h3>
3940 <p>Mixing <code class="directive">Options</code> with a <code>+</code> or
3941 <code>-</code> with those without is not valid syntax and will be
3942 rejected during server startup by the syntax check with an abort.</p>
3945 <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>
3947 <pre class="prettyprint lang-config"><Directory "/web/docs">
3948 Options Indexes FollowSymLinks
3951 <Directory "/web/docs/spec">
3953 </Directory></pre>
3956 <p>then only <code>Includes</code> will be set for the
3957 <code>/web/docs/spec</code> directory. However if the second
3958 <code class="directive">Options</code> directive uses the <code>+</code> and
3959 <code>-</code> symbols:</p>
3961 <pre class="prettyprint lang-config"><Directory "/web/docs">
3962 Options Indexes FollowSymLinks
3965 <Directory "/web/docs/spec">
3966 Options +Includes -Indexes
3967 </Directory></pre>
3970 <p>then the options <code>FollowSymLinks</code> and
3971 <code>Includes</code> are set for the <code>/web/docs/spec</code>
3974 <div class="note"><h3>Note</h3>
3975 <p>Using <code>-IncludesNOEXEC</code> or
3976 <code>-Includes</code> disables server-side includes completely
3977 regardless of the previous setting.</p>
3980 <p>The default in the absence of any other settings is
3981 <code>FollowSymlinks</code>.</p>
3984 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3985 <div class="directive-section"><h2><a name="Protocol" id="Protocol">Protocol</a> <a name="protocol" id="protocol">Directive</a></h2>
3986 <table class="directive">
3987 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Protocol for a listening socket</td></tr>
3988 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Protocol <var>protocol</var></code></td></tr>
3989 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3990 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3991 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3992 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>On Windows, only available from Apache 2.3.3 and later.</td></tr>
3994 <p>This directive specifies the protocol used for a specific listening socket.
3995 The protocol is used to determine which module should handle a request and
3996 to apply protocol specific optimizations with the <code class="directive">AcceptFilter</code>
3999 <p>You only need to set the protocol if you are running on non-standard ports;
4000 otherwise, <code>http</code> is assumed for port 80 and <code>https</code>
4003 <p>For example, if you are running <code>https</code> on a non-standard port,
4004 specify the protocol explicitly:</p>
4006 <pre class="prettyprint lang-config">Protocol https</pre>
4009 <p>You can also specify the protocol using the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code> directive.</p>
4013 <li><code class="directive"><a href="#acceptfilter">AcceptFilter</a></code></li>
4014 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4017 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4018 <div class="directive-section"><h2><a name="Protocols" id="Protocols">Protocols</a> <a name="protocols" id="protocols">Directive</a></h2>
4019 <table class="directive">
4020 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Protocols available for a server/virtual host</td></tr>
4021 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Protocols <var>protocol</var> ...</code></td></tr>
4022 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Protocols http/1.1</code></td></tr>
4023 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4024 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4025 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4026 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Only available from Apache 2.4.17 and later.</td></tr>
4028 <p>This directive specifies the list of protocols supported for a
4029 server/virtual host. The list determines the allowed protocols
4030 a client may negotiate for this server/host.</p>
4032 <p>You need to set protocols if you want to extend the available
4033 protocols for a server/host. By default, only the http/1.1 protocol
4034 (which includes the compatibility with 1.0 and 0.9 clients) is
4037 <p>For example, if you want to support HTTP/2 for a server with TLS,
4040 <pre class="prettyprint lang-config">Protocols h2 http/1.1</pre>
4043 <p>Valid protocols are <code>http/1.1</code> for http and https connections,
4044 <code>h2</code> on https connections and <code>h2c</code> for http
4045 connections. Modules may enable more protocols.</p>
4047 <p>It is safe to specify protocols that are unavailable/disabled. Such
4048 protocol names will simply be ignored.</p>
4050 <p>Protocols specified in base servers are inherited for virtual hosts
4051 only if the virtual host has no own Protocols directive. Or, the other
4052 way around, Protocols directives in virtual hosts replace any
4053 such directive in the base server.
4059 <li><code class="directive"><a href="#protocolshonororder">ProtocolsHonorOrder</a></code></li>
4062 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4063 <div class="directive-section"><h2><a name="ProtocolsHonorOrder" id="ProtocolsHonorOrder">ProtocolsHonorOrder</a> <a name="protocolshonororder" id="protocolshonororder">Directive</a></h2>
4064 <table class="directive">
4065 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines if order of Protocols determines precedence during negotiation</td></tr>
4066 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProtocolsHonorOrder On|Off</code></td></tr>
4067 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProtocolsHonorOrder On</code></td></tr>
4068 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4069 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4070 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4071 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Only available from Apache 2.4.17 and later.</td></tr>
4073 <p>This directive specifies if the server should honor the order in which
4074 the <code class="directive">Protocols</code> directive lists protocols.</p>
4076 <p>If configured Off, the client supplied list order of protocols has
4077 precedence over the order in the server configuration.</p>
4079 <p>With <code class="directive">ProtocolsHonorOrder</code> set to <code>on</code>
4080 (default), the client ordering does not matter and only the ordering
4081 in the server settings influences the outcome of the protocol
4087 <li><code class="directive"><a href="#protocols">Protocols</a></code></li>
4090 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4091 <div class="directive-section"><h2><a name="QualifyRedirectURL" id="QualifyRedirectURL">QualifyRedirectURL</a> <a name="qualifyredirecturl" id="qualifyredirecturl">Directive</a></h2>
4092 <table class="directive">
4093 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Controls whether the REDIRECT_URL environment variable is
4094 fully qualified</td></tr>
4095 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>QualifyRedirectURL ON|OFF</code></td></tr>
4096 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>QualifyRedirectURL OFF</code></td></tr>
4097 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4098 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4099 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4100 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4101 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Directive supported in 2.4.18 and later. 2.4.17 acted
4102 as if 'QualifyRedirectURL ON' was configured.</td></tr>
4104 <p>This directive controls whether the server will ensure that the
4105 REDIRECT_URL environment variable is fully qualified. By default,
4106 the variable contains the verbatim URL requested by the client,
4107 such as "/index.html". With <code class="directive"><a href="#qualifyredirecturl on">QualifyRedirectURL ON</a></code>, the same request would result in a
4108 value such as "http://www.example.com/index.html".</p>
4109 <p>Even without this directive set, when a request is issued against a
4110 fully qualified URL, REDIRECT_URL will remain fully qualified.
4114 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4115 <div class="directive-section"><h2><a name="RegisterHttpMethod" id="RegisterHttpMethod">RegisterHttpMethod</a> <a name="registerhttpmethod" id="registerhttpmethod">Directive</a></h2>
4116 <table class="directive">
4117 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Register non-standard HTTP methods</td></tr>
4118 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>RegisterHttpMethod <var>method</var> [<var>method</var> [...]]</code></td></tr>
4119 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4120 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4121 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4123 <p>HTTP Methods that are not conforming to the relevant RFCs are normally
4124 rejected by request processing in Apache HTTPD. To avoid this, modules
4125 can register non-standard HTTP methods they support.
4126 The <code class="directive">RegisterHttpMethod</code> allows to register such
4127 methods manually. This can be useful if such methods are forwarded
4128 for external processing, e.g. to a CGI script.</p>
4131 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4132 <div class="directive-section"><h2><a name="RLimitCPU" id="RLimitCPU">RLimitCPU</a> <a name="rlimitcpu" id="rlimitcpu">Directive</a></h2>
4133 <table class="directive">
4134 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the CPU consumption of processes launched
4135 by Apache httpd children</td></tr>
4136 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>RLimitCPU <var>seconds</var>|max [<var>seconds</var>|max]</code></td></tr>
4137 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
4138 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4139 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
4140 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4141 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4143 <p>Takes 1 or 2 parameters. The first parameter sets the soft
4144 resource limit for all processes and the second parameter sets
4145 the maximum resource limit. Either parameter can be a number,
4146 or <code>max</code> to indicate to the server that the limit should
4147 be set to the maximum allowed by the operating system
4148 configuration. Raising the maximum resource limit requires that
4149 the server is running as <code>root</code> or in the initial startup
4152 <p>This applies to processes forked from Apache httpd children
4153 servicing requests, not the Apache httpd children themselves. This
4154 includes CGI scripts and SSI exec commands, but not any
4155 processes forked from the Apache httpd parent, such as piped
4158 <p>CPU resource limits are expressed in seconds per
4163 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
4164 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
4167 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4168 <div class="directive-section"><h2><a name="RLimitMEM" id="RLimitMEM">RLimitMEM</a> <a name="rlimitmem" id="rlimitmem">Directive</a></h2>
4169 <table class="directive">
4170 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the memory consumption of processes launched
4171 by Apache httpd children</td></tr>
4172 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>RLimitMEM <var>bytes</var>|max [<var>bytes</var>|max]</code></td></tr>
4173 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
4174 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4175 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
4176 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4177 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4179 <p>Takes 1 or 2 parameters. The first parameter sets the soft
4180 resource limit for all processes and the second parameter sets
4181 the maximum resource limit. Either parameter can be a number,
4182 or <code>max</code> to indicate to the server that the limit should
4183 be set to the maximum allowed by the operating system
4184 configuration. Raising the maximum resource limit requires that
4185 the server is running as <code>root</code> or in the initial startup
4188 <p>This applies to processes forked from Apache httpd children
4189 servicing requests, not the Apache httpd children themselves. This
4190 includes CGI scripts and SSI exec commands, but not any
4191 processes forked from the Apache httpd parent, such as piped
4194 <p>Memory resource limits are expressed in bytes per
4199 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
4200 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
4203 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4204 <div class="directive-section"><h2><a name="RLimitNPROC" id="RLimitNPROC">RLimitNPROC</a> <a name="rlimitnproc" id="rlimitnproc">Directive</a></h2>
4205 <table class="directive">
4206 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of processes that can be launched by
4207 processes launched by Apache httpd children</td></tr>
4208 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>RLimitNPROC <var>number</var>|max [<var>number</var>|max]</code></td></tr>
4209 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
4210 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4211 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
4212 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4213 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4215 <p>Takes 1 or 2 parameters. The first parameter sets the soft
4216 resource limit for all processes, and the second parameter sets
4217 the maximum resource limit. Either parameter can be a number,
4218 or <code>max</code> to indicate to the server that the limit
4219 should be set to the maximum allowed by the operating system
4220 configuration. Raising the maximum resource limit requires that
4221 the server is running as <code>root</code> or in the initial startup
4224 <p>This applies to processes forked from Apache httpd children
4225 servicing requests, not the Apache httpd children themselves. This
4226 includes CGI scripts and SSI exec commands, but not any
4227 processes forked from the Apache httpd parent, such as piped
4230 <p>Process limits control the number of processes per user.</p>
4232 <div class="note"><h3>Note</h3>
4233 <p>If CGI processes are <strong>not</strong> running
4234 under user ids other than the web server user id, this directive
4235 will limit the number of processes that the server itself can
4236 create. Evidence of this situation will be indicated by
4237 <strong><code>cannot fork</code></strong> messages in the
4238 <code>error_log</code>.</p>
4243 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
4244 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
4247 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4248 <div class="directive-section"><h2><a name="ScriptInterpreterSource" id="ScriptInterpreterSource">ScriptInterpreterSource</a> <a name="scriptinterpretersource" id="scriptinterpretersource">Directive</a></h2>
4249 <table class="directive">
4250 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
4252 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ScriptInterpreterSource Registry|Registry-Strict|Script</code></td></tr>
4253 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ScriptInterpreterSource Script</code></td></tr>
4254 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4255 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4256 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4257 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4258 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Win32 only.</td></tr>
4260 <p>This directive is used to control how Apache httpd finds the
4261 interpreter used to run CGI scripts. The default setting is
4262 <code>Script</code>. This causes Apache httpd to use the interpreter pointed to
4263 by the shebang line (first line, starting with <code>#!</code>) in the
4264 script. On Win32 systems this line usually looks like:</p>
4266 <pre class="prettyprint lang-perl">#!C:/Perl/bin/perl.exe</pre>
4269 <p>or, if <code>perl</code> is in the <code>PATH</code>, simply:</p>
4271 <pre class="prettyprint lang-perl">#!perl</pre>
4274 <p>Setting <code>ScriptInterpreterSource Registry</code> will
4275 cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
4276 searched using the script file extension (e.g., <code>.pl</code>) as a
4277 search key. The command defined by the registry subkey
4278 <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
4279 <code>Shell\Open\Command</code> is used to open the script file. If the
4280 registry keys cannot be found, Apache httpd falls back to the behavior of the
4281 <code>Script</code> option.</p>
4283 <div class="warning"><h3>Security</h3>
4284 <p>Be careful when using <code>ScriptInterpreterSource
4285 Registry</code> with <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>'ed directories, because
4286 Apache httpd will try to execute <strong>every</strong> file within this
4287 directory. The <code>Registry</code> setting may cause undesired
4288 program calls on files which are typically not executed. For
4289 example, the default open command on <code>.htm</code> files on
4290 most Windows systems will execute Microsoft Internet Explorer, so
4291 any HTTP request for an <code>.htm</code> file existing within the
4292 script directory would start the browser in the background on the
4293 server. This is a good way to crash your system within a minute or
4297 <p>The option <code>Registry-Strict</code> which is new in Apache HTTP Server
4298 2.0 does the same thing as <code>Registry</code> but uses only the
4299 subkey <code>Shell\ExecCGI\Command</code>. The
4300 <code>ExecCGI</code> key is not a common one. It must be
4301 configured manually in the windows registry and hence prevents
4302 accidental program calls on your system.</p>
4305 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4306 <div class="directive-section"><h2><a name="SeeRequestTail" id="SeeRequestTail">SeeRequestTail</a> <a name="seerequesttail" id="seerequesttail">Directive</a></h2>
4307 <table class="directive">
4308 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine if mod_status displays the first 63 characters
4309 of a request or the last 63, assuming the request itself is greater than
4311 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SeeRequestTail On|Off</code></td></tr>
4312 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SeeRequestTail Off</code></td></tr>
4313 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4314 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4315 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4317 <p>mod_status with <code>ExtendedStatus On</code>
4318 displays the actual request being handled.
4319 For historical purposes, only 63 characters of the request
4320 are actually stored for display purposes. This directive
4321 controls whether the 1st 63 characters are stored (the previous
4322 behavior and the default) or if the last 63 characters are. This
4323 is only applicable, of course, if the length of the request is
4324 64 characters or greater.</p>
4326 <p>If Apache httpd is handling <code>GET /disk1/storage/apache/htdocs/images/imagestore1/food/apples.jpg HTTP/1.1</code> mod_status displays as follows:
4329 <table class="bordered">
4331 <th>Off (default)</th>
4332 <td>GET /disk1/storage/apache/htdocs/images/imagestore1/food/apples</td>
4336 <td>orage/apache/htdocs/images/imagestore1/food/apples.jpg HTTP/1.1</td>
4342 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4343 <div class="directive-section"><h2><a name="ServerAdmin" id="ServerAdmin">ServerAdmin</a> <a name="serveradmin" id="serveradmin">Directive</a></h2>
4344 <table class="directive">
4345 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Email address that the server includes in error
4346 messages sent to the client</td></tr>
4347 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAdmin <var>email-address</var>|<var>URL</var></code></td></tr>
4348 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4349 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4350 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4352 <p>The <code class="directive">ServerAdmin</code> sets the contact address
4353 that the server includes in any error messages it returns to the
4354 client. If the <code>httpd</code> doesn't recognize the supplied argument
4356 assumes, that it's an <var>email-address</var> and prepends it with
4357 <code>mailto:</code> in hyperlink targets. However, it's recommended to
4358 actually use an email address, since there are a lot of CGI scripts that
4359 make that assumption. If you want to use an URL, it should point to another
4360 server under your control. Otherwise users may not be able to contact you in
4363 <p>It may be worth setting up a dedicated address for this, e.g.</p>
4365 <pre class="prettyprint lang-config">ServerAdmin www-admin@foo.example.com</pre>
4367 <p>as users do not always mention that they are talking about the
4371 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4372 <div class="directive-section"><h2><a name="ServerAlias" id="ServerAlias">ServerAlias</a> <a name="serveralias" id="serveralias">Directive</a></h2>
4373 <table class="directive">
4374 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Alternate names for a host used when matching requests
4375 to name-virtual hosts</td></tr>
4376 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</code></td></tr>
4377 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
4378 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4379 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4381 <p>The <code class="directive">ServerAlias</code> directive sets the
4382 alternate names for a host, for use with <a href="../vhosts/name-based.html">name-based virtual hosts</a>. The
4383 <code class="directive">ServerAlias</code> may include wildcards, if appropriate.</p>
4385 <pre class="prettyprint lang-config"><VirtualHost *:80>
4386 ServerName server.example.com
4387 ServerAlias server server2.example.com server2
4388 ServerAlias *.example.com
4389 UseCanonicalName Off
4391 </VirtualHost></pre>
4394 <p>Name-based virtual hosts for the best-matching set of <code class="directive"><a href="#virtualhost"><virtualhost></a></code>s are processed
4395 in the order they appear in the configuration. The first matching <code class="directive"><a href="#servername">ServerName</a></code> or <code class="directive"><a href="#serveralias">ServerAlias</a></code> is used, with no different precedence for wildcards
4396 (nor for ServerName vs. ServerAlias). </p>
4398 <p>The complete list of names in the <code class="directive"><a href="#virtualhost"><VirtualHost></a></code>
4399 directive are treated just like a (non wildcard)
4400 <code class="directive">ServerAlias</code>.</p>
4405 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
4406 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4409 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4410 <div class="directive-section"><h2><a name="ServerName" id="ServerName">ServerName</a> <a name="servername" id="servername">Directive</a></h2>
4411 <table class="directive">
4412 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hostname and port that the server uses to identify
4414 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerName [<var>scheme</var>://]<var>domain-name</var>|<var>ip-address</var>[:<var>port</var>]</code></td></tr>
4415 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4416 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4417 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4419 <p>The <code class="directive">ServerName</code> directive sets the
4420 request scheme, hostname and port that the server uses to identify itself.
4423 <p><code class="directive">ServerName</code> is used (possibly
4424 in conjunction with <code class="directive"><a href="#serveralias">ServerAlias</a></code>) to uniquely
4425 identify a virtual host, when using <a href="../vhosts/name-based.html">name-based virtual hosts</a>.</p>
4427 <p>Additionally, this is used when
4428 creating self-referential redirection URLs when
4429 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> is set to a non-default
4432 <p>For example, if the name of the
4433 machine hosting the web server is <code>simple.example.com</code>,
4434 but the machine also has the DNS alias <code>www.example.com</code>
4435 and you wish the web server to be so identified, the following
4436 directive should be used:</p>
4438 <pre class="prettyprint lang-config">ServerName www.example.com</pre>
4441 <p>The <code class="directive">ServerName</code> directive
4442 may appear anywhere within the definition of a server. However,
4443 each appearance overrides the previous appearance (within that
4446 <p>If no <code class="directive">ServerName</code> is specified, the
4447 server attempts to deduce the client visible hostname by first asking
4448 the operating system for the system hostname, and if that fails,
4449 performing a reverse lookup on an IP address present on the system.</p>
4451 <p>If no port is specified in the
4452 <code class="directive">ServerName</code>, then the server will use the
4453 port from the incoming request. For optimal reliability and
4454 predictability, you should specify an explicit hostname and port
4455 using the <code class="directive">ServerName</code> directive.</p>
4457 <p>If you are using <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
4458 the <code class="directive">ServerName</code> inside a
4459 <code class="directive"><a href="#virtualhost"><VirtualHost></a></code>
4460 section specifies what hostname must appear in the request's
4461 <code>Host:</code> header to match this virtual host.</p>
4463 <p>Sometimes, the server runs behind a device that processes SSL,
4464 such as a reverse proxy, load balancer or SSL offload
4465 appliance. When this is the case, specify the
4466 <code>https://</code> scheme and the port number to which the
4467 clients connect in the <code class="directive">ServerName</code> directive
4468 to make sure that the server generates the correct
4469 self-referential URLs.
4472 <p>See the description of the
4473 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> and
4474 <code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code> directives for
4475 settings which determine whether self-referential URLs (e.g., by the
4476 <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> module) will refer to the
4477 specified port, or to the port number given in the client's request.
4480 <div class="warning">
4481 <p>Failure to set <code class="directive">ServerName</code> to a name that
4482 your server can resolve to an IP address will result in a startup
4483 warning. <code>httpd</code> will then use whatever hostname it can
4484 determine, using the system's <code>hostname</code> command. This
4485 will almost never be the hostname you actually want.</p>
4486 <div class="example"><p><code>
4487 httpd: Could not reliably determine the server's fully qualified domain name, using rocinante.local for ServerName
4494 <li><a href="../dns-caveats.html">Issues Regarding DNS and
4495 Apache HTTP Server</a></li>
4496 <li><a href="../vhosts/">Apache HTTP Server virtual host
4497 documentation</a></li>
4498 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
4499 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
4500 <li><code class="directive"><a href="#serveralias">ServerAlias</a></code></li>
4503 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4504 <div class="directive-section"><h2><a name="ServerPath" id="ServerPath">ServerPath</a> <a name="serverpath" id="serverpath">Directive</a></h2>
4505 <table class="directive">
4506 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Legacy URL pathname for a name-based virtual host that
4507 is accessed by an incompatible browser</td></tr>
4508 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerPath <var>URL-path</var></code></td></tr>
4509 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
4510 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4511 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4513 <p>The <code class="directive">ServerPath</code> directive sets the legacy
4514 URL pathname for a host, for use with <a href="../vhosts/">name-based virtual hosts</a>.</p>
4518 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4521 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4522 <div class="directive-section"><h2><a name="ServerRoot" id="ServerRoot">ServerRoot</a> <a name="serverroot" id="serverroot">Directive</a></h2>
4523 <table class="directive">
4524 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server installation</td></tr>
4525 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerRoot <var>directory-path</var></code></td></tr>
4526 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerRoot /usr/local/apache</code></td></tr>
4527 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4528 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4529 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4531 <p>The <code class="directive">ServerRoot</code> directive sets the
4532 directory in which the server lives. Typically it will contain the
4533 subdirectories <code>conf/</code> and <code>logs/</code>. Relative
4534 paths in other configuration directives (such as <code class="directive"><a href="#include">Include</a></code> or <code class="directive"><a href="../mod/mod_so.html#loadmodule">LoadModule</a></code>, for example) are taken as
4535 relative to this directory.</p>
4537 <pre class="prettyprint lang-config">ServerRoot "/home/httpd"</pre>
4540 <p>The default location of <code class="directive">ServerRoot</code> may be
4541 modified by using the <code>--prefix</code> argument to
4542 <a href="../programs/configure.html"><code>configure</code></a>, and
4543 most third-party distributions of the server have a different
4544 default location from the one listed above.</p>
4549 <li><a href="../invoking.html">the <code>-d</code>
4550 option to <code>httpd</code></a></li>
4551 <li><a href="../misc/security_tips.html#serverroot">the
4552 security tips</a> for information on how to properly set
4553 permissions on the <code class="directive">ServerRoot</code></li>
4556 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4557 <div class="directive-section"><h2><a name="ServerSignature" id="ServerSignature">ServerSignature</a> <a name="serversignature" id="serversignature">Directive</a></h2>
4558 <table class="directive">
4559 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the footer on server-generated documents</td></tr>
4560 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerSignature On|Off|EMail</code></td></tr>
4561 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerSignature Off</code></td></tr>
4562 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4563 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
4564 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4565 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4567 <p>The <code class="directive">ServerSignature</code> directive allows the
4568 configuration of a trailing footer line under server-generated
4569 documents (error messages, <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> ftp directory
4570 listings, <code class="module"><a href="../mod/mod_info.html">mod_info</a></code> output, ...). The reason why you
4571 would want to enable such a footer line is that in a chain of proxies,
4572 the user often has no possibility to tell which of the chained servers
4573 actually produced a returned error message.</p>
4575 <p>The <code>Off</code>
4576 setting, which is the default, suppresses the footer line (and is
4577 therefore compatible with the behavior of Apache-1.2 and
4578 below). The <code>On</code> setting simply adds a line with the
4579 server version number and <code class="directive"><a href="#servername">ServerName</a></code> of the serving virtual host,
4580 and the <code>EMail</code> setting additionally creates a
4581 "mailto:" reference to the <code class="directive"><a href="#serveradmin">ServerAdmin</a></code> of the referenced
4584 <p>After version 2.0.44, the details of the server version number
4585 presented are controlled by the <code class="directive"><a href="#servertokens">ServerTokens</a></code> directive.</p>
4589 <li><code class="directive"><a href="#servertokens">ServerTokens</a></code></li>
4592 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4593 <div class="directive-section"><h2><a name="ServerTokens" id="ServerTokens">ServerTokens</a> <a name="servertokens" id="servertokens">Directive</a></h2>
4594 <table class="directive">
4595 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the <code>Server</code> HTTP response
4597 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerTokens Major|Minor|Min[imal]|Prod[uctOnly]|OS|Full</code></td></tr>
4598 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerTokens Full</code></td></tr>
4599 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4600 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4601 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4603 <p>This directive controls whether <code>Server</code> response
4604 header field which is sent back to clients includes a
4605 description of the generic OS-type of the server as well as
4606 information about compiled-in modules.</p>
4609 <dt><code>ServerTokens Full</code> (or not specified)</dt>
4611 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4612 (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
4614 <dt><code>ServerTokens Prod[uctOnly]</code></dt>
4616 <dd>Server sends (<em>e.g.</em>): <code>Server:
4619 <dt><code>ServerTokens Major</code></dt>
4621 <dd>Server sends (<em>e.g.</em>): <code>Server:
4622 Apache/2</code></dd>
4624 <dt><code>ServerTokens Minor</code></dt>
4626 <dd>Server sends (<em>e.g.</em>): <code>Server:
4627 Apache/2.4</code></dd>
4629 <dt><code>ServerTokens Min[imal]</code></dt>
4631 <dd>Server sends (<em>e.g.</em>): <code>Server:
4632 Apache/2.4.2</code></dd>
4634 <dt><code>ServerTokens OS</code></dt>
4636 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4641 <p>This setting applies to the entire server, and cannot be
4642 enabled or disabled on a virtualhost-by-virtualhost basis.</p>
4644 <p>After version 2.0.44, this directive also controls the
4645 information presented by the <code class="directive"><a href="#serversignature">ServerSignature</a></code> directive.</p>
4647 <div class="note">Setting <code class="directive">ServerTokens</code> to less than
4648 <code>minimal</code> is not recommended because it makes it more
4649 difficult to debug interoperational problems. Also note that
4650 disabling the Server: header does nothing at all to make your
4651 server more secure. The idea of "security through obscurity"
4652 is a myth and leads to a false sense of safety.</div>
4656 <li><code class="directive"><a href="#serversignature">ServerSignature</a></code></li>
4659 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4660 <div class="directive-section"><h2><a name="SetHandler" id="SetHandler">SetHandler</a> <a name="sethandler" id="sethandler">Directive</a></h2>
4661 <table class="directive">
4662 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be processed by a
4664 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetHandler <var>handler-name</var>|none|<var>expression</var></code></td></tr>
4665 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4666 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4667 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4668 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4669 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.5 and later</td></tr>
4671 <p>When placed into an <code>.htaccess</code> file or a
4672 <code class="directive"><a href="#directory"><Directory></a></code> or
4673 <code class="directive"><a href="#location"><Location></a></code>
4674 section, this directive forces all matching files to be parsed
4675 through the <a href="../handler.html">handler</a> given by
4676 <var>handler-name</var>. For example, if you had a directory you
4677 wanted to be parsed entirely as imagemap rule files, regardless
4678 of extension, you might put the following into an
4679 <code>.htaccess</code> file in that directory:</p>
4681 <pre class="prettyprint lang-config">SetHandler imap-file</pre>
4684 <p>Another example: if you wanted to have the server display a
4685 status report whenever a URL of
4686 <code>http://servername/status</code> was called, you might put
4687 the following into <code>httpd.conf</code>:</p>
4689 <pre class="prettyprint lang-config"><Location "/status">
4690 SetHandler server-status
4691 </Location></pre>
4694 <p>You could also use this directive to configure a particular
4695 handler for files with a particular file extension. For example:</p>
4697 <pre class="prettyprint lang-config"><FilesMatch "\.php$">
4698 SetHandler application/x-httpd-php
4699 </FilesMatch></pre>
4702 <p>String-valued expressions can be used to reference per-request
4703 variables, including backreferences to named regular expressions:</p>
4705 <pre class="prettyprint lang-config"><LocationMatch ^/app/(?<sub>[^/]+)/>
4706 SetHandler "proxy:unix:/var/run/app_%{env:MATCH_sub}.sock|fcgi://localhost:8080"
4707 </LocationMatch></pre>
4710 <p>You can override an earlier defined <code class="directive">SetHandler</code>
4711 directive by using the value <code>None</code>.</p>
4713 <div class="note"><h3>Note</h3>
4714 <p>Because <code class="directive">SetHandler</code> overrides default handlers,
4715 normal behavior such as handling of URLs ending in a slash (/) as
4716 directories or index files is suppressed.</p></div>
4720 <li><code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code></li>
4723 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4724 <div class="directive-section"><h2><a name="SetInputFilter" id="SetInputFilter">SetInputFilter</a> <a name="setinputfilter" id="setinputfilter">Directive</a></h2>
4725 <table class="directive">
4726 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process client requests and POST
4728 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetInputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4729 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4730 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4731 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4732 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4734 <p>The <code class="directive">SetInputFilter</code> directive sets the
4735 filter or filters which will process client requests and POST
4736 input when they are received by the server. This is in addition to
4737 any filters defined elsewhere, including the
4738 <code class="directive"><a href="../mod/mod_mime.html#addinputfilter">AddInputFilter</a></code>
4741 <p>If more than one filter is specified, they must be separated
4742 by semicolons in the order in which they should process the
4747 <li><a href="../filter.html">Filters</a> documentation</li>
4750 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4751 <div class="directive-section"><h2><a name="SetOutputFilter" id="SetOutputFilter">SetOutputFilter</a> <a name="setoutputfilter" id="setoutputfilter">Directive</a></h2>
4752 <table class="directive">
4753 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process responses from the
4755 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4756 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4757 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4758 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4759 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4761 <p>The <code class="directive">SetOutputFilter</code> directive sets the filters
4762 which will process responses from the server before they are
4763 sent to the client. This is in addition to any filters defined
4764 elsewhere, including the
4765 <code class="directive"><a href="../mod/mod_mime.html#addoutputfilter">AddOutputFilter</a></code>
4768 <p>For example, the following configuration will process all files
4769 in the <code>/www/data/</code> directory for server-side
4772 <pre class="prettyprint lang-config"><Directory "/www/data/">
4773 SetOutputFilter INCLUDES
4774 </Directory></pre>
4777 <p>If more than one filter is specified, they must be separated
4778 by semicolons in the order in which they should process the
4783 <li><a href="../filter.html">Filters</a> documentation</li>
4786 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4787 <div class="directive-section"><h2><a name="TimeOut" id="TimeOut">TimeOut</a> <a name="timeout" id="timeout">Directive</a></h2>
4788 <table class="directive">
4789 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for
4790 certain events before failing a request</td></tr>
4791 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TimeOut <var>seconds</var></code></td></tr>
4792 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TimeOut 60</code></td></tr>
4793 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4794 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4795 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4797 <p>The <code class="directive">TimeOut</code> directive defines the length
4798 of time Apache httpd will wait for I/O in various circumstances:</p>
4801 <li><p>When reading data from the client, the length of time to
4802 wait for a TCP packet to arrive if the read buffer is
4804 <p> For initial data on a new connection, this directive doesn't
4805 take effect until after any configured <code class="directive"><a href="#acceptfilter">
4806 AcceptFilter</a></code> has passed the new connection to the server.</p>
4809 <li>When writing data to the client, the length of time to wait
4810 for an acknowledgement of a packet if the send buffer is
4813 <li>In <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code> and <code class="module"><a href="../mod/mod_cgid.html">mod_cgid</a></code>,
4814 the length of time to wait for any individual block of output
4815 from a CGI script.</li>
4817 <li>In <code class="module"><a href="../mod/mod_ext_filter.html">mod_ext_filter</a></code>, the length of time to
4818 wait for output from a filtering process.</li>
4820 <li>In <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>, the default timeout value if
4821 <code class="directive"><a href="../mod/mod_proxy.html#proxytimeout">ProxyTimeout</a></code> is not
4827 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4828 <div class="directive-section"><h2><a name="TraceEnable" id="TraceEnable">TraceEnable</a> <a name="traceenable" id="traceenable">Directive</a></h2>
4829 <table class="directive">
4830 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines the behavior on <code>TRACE</code> requests</td></tr>
4831 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TraceEnable <var>[on|off|extended]</var></code></td></tr>
4832 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TraceEnable on</code></td></tr>
4833 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4834 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4835 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4837 <p>This directive overrides the behavior of <code>TRACE</code> for both
4838 the core server and <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>. The default
4839 <code>TraceEnable on</code> permits <code>TRACE</code> requests per
4840 RFC 2616, which disallows any request body to accompany the request.
4841 <code>TraceEnable off</code> causes the core server and
4842 <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> to return a <code>405</code> (Method not
4843 allowed) error to the client.</p>
4845 <p>Finally, for testing and diagnostic purposes only, request
4846 bodies may be allowed using the non-compliant <code>TraceEnable
4847 extended</code> directive. The core (as an origin server) will
4848 restrict the request body to 64Kb (plus 8Kb for chunk headers if
4849 <code>Transfer-Encoding: chunked</code> is used). The core will
4850 reflect the full headers and all chunk headers with the response
4851 body. As a proxy server, the request body is not restricted to 64Kb.</p>
4853 <div class="note"><h3>Note</h3>
4855 <p>Despite claims to the contrary, enabling the <code>TRACE</code>
4856 method does not expose any security vulnerability in Apache httpd.
4857 The <code>TRACE</code> method is defined by the HTTP/1.1
4858 specification and implementations are expected to support it.</p>
4863 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4864 <div class="directive-section"><h2><a name="UnDefine" id="UnDefine">UnDefine</a> <a name="undefine" id="undefine">Directive</a></h2>
4865 <table class="directive">
4866 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Undefine the existence of a variable</td></tr>
4867 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UnDefine <var>parameter-name</var></code></td></tr>
4868 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4869 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4870 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4872 <p>Undoes the effect of a <code class="directive"><a href="#define">Define</a></code> or
4873 of passing a <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</p>
4874 <p>This directive can be used to toggle the use of <code class="directive"><a href="#ifdefine"><IfDefine></a></code> sections without needing to alter
4875 <code>-D</code> arguments in any startup scripts.</p>
4876 <p>While this directive is supported in virtual host context,
4877 the changes it makes are visible to any later configuration
4878 directives, beyond any enclosing virtual host.</p>
4882 <li><code class="directive"><a href="#define">Define</a></code></li>
4883 <li><code class="directive"><a href="#ifdefine">IfDefine</a></code></li>
4886 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4887 <div class="directive-section"><h2><a name="UseCanonicalName" id="UseCanonicalName">UseCanonicalName</a> <a name="usecanonicalname" id="usecanonicalname">Directive</a></h2>
4888 <table class="directive">
4889 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own name and
4891 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalName On|Off|DNS</code></td></tr>
4892 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalName Off</code></td></tr>
4893 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4894 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4895 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4897 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4898 URL -- that is, a URL that refers back to the same server. With
4899 <code>UseCanonicalName On</code> Apache httpd will use the hostname and port
4900 specified in the <code class="directive"><a href="#servername">ServerName</a></code>
4901 directive to construct the canonical name for the server. This name
4902 is used in all self-referential URLs, and for the values of
4903 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>
4905 <p>With <code>UseCanonicalName Off</code> Apache httpd will form
4906 self-referential URLs using the hostname and port supplied by
4907 the client if any are supplied (otherwise it will use the
4908 canonical name, as defined above). These values are the same
4909 that are used to implement <a href="../vhosts/name-based.html">name-based virtual hosts</a>
4910 and are available with the same clients. The CGI variables
4911 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
4912 constructed from the client supplied values as well.</p>
4914 <p>An example where this may be useful is on an intranet server
4915 where you have users connecting to the machine using short
4916 names such as <code>www</code>. You'll notice that if the users
4917 type a shortname and a URL which is a directory, such as
4918 <code>http://www/splat</code>, <em>without the trailing
4919 slash</em>, then Apache httpd will redirect them to
4920 <code>http://www.example.com/splat/</code>. If you have
4921 authentication enabled, this will cause the user to have to
4922 authenticate twice (once for <code>www</code> and once again
4923 for <code>www.example.com</code> -- see <a href="http://wiki.apache.org/httpd/FAQ#Why_does_Apache_ask_for_my_password_twice_before_serving_a_file.3F">
4924 the FAQ on this subject for more information</a>). But if
4925 <code class="directive">UseCanonicalName</code> is set <code>Off</code>, then
4926 Apache httpd will redirect to <code>http://www/splat/</code>.</p>
4928 <p>There is a third option, <code>UseCanonicalName DNS</code>,
4929 which is intended for use with mass IP-based virtual hosting to
4930 support ancient clients that do not provide a
4931 <code>Host:</code> header. With this option, Apache httpd does a
4932 reverse DNS lookup on the server IP address that the client
4933 connected to in order to work out self-referential URLs.</p>
4935 <div class="warning"><h3>Warning</h3>
4936 <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>,
4937 they may be broken by this option. The client is essentially free
4938 to give whatever value they want as a hostname. But if the CGI is
4939 only using <code>SERVER_NAME</code> to construct self-referential URLs,
4940 then it should be just fine.</p>
4945 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
4946 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4947 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4950 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4951 <div class="directive-section"><h2><a name="UseCanonicalPhysicalPort" id="UseCanonicalPhysicalPort">UseCanonicalPhysicalPort</a> <a name="usecanonicalphysicalport" id="usecanonicalphysicalport">Directive</a></h2>
4952 <table class="directive">
4953 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own port</td></tr>
4954 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalPhysicalPort On|Off</code></td></tr>
4955 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalPhysicalPort Off</code></td></tr>
4956 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4957 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4958 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4960 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4961 URL -- that is, a URL that refers back to the same server. With
4962 <code>UseCanonicalPhysicalPort On</code>, Apache httpd will, when
4963 constructing the canonical port for the server to honor
4964 the <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> directive,
4965 provide the actual physical port number being used by this request
4966 as a potential port. With <code>UseCanonicalPhysicalPort Off</code>,
4967 Apache httpd will not ever use the actual physical port number, instead
4968 relying on all configured information to construct a valid port number.</p>
4970 <div class="note"><h3>Note</h3>
4971 <p>The ordering of the lookup when the physical port is used is as
4974 <dt><code>UseCanonicalName On</code></dt>
4977 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4978 <li>Physical port</li>
4979 <li>Default port</li>
4982 <dt><code>UseCanonicalName Off | DNS</code></dt>
4985 <li>Parsed port from <code>Host:</code> header</li>
4986 <li>Physical port</li>
4987 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4988 <li>Default port</li>
4993 <p>With <code>UseCanonicalPhysicalPort Off</code>, the
4994 physical ports are removed from the ordering.</p>
5000 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
5001 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
5002 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
5005 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
5006 <div class="directive-section"><h2><a name="VirtualHost" id="VirtualHost"><VirtualHost></a> <a name="virtualhost" id="virtualhost">Directive</a></h2>
5007 <table class="directive">
5008 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only to a specific
5009 hostname or IP address</td></tr>
5010 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><VirtualHost
5011 <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
5012 ...> ... </VirtualHost></code></td></tr>
5013 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
5014 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
5015 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
5017 <p><code class="directive"><VirtualHost></code> and
5018 <code></VirtualHost></code> are used to enclose a group of
5019 directives that will apply only to a particular virtual host. Any
5020 directive that is allowed in a virtual host context may be
5021 used. When the server receives a request for a document on a
5022 particular virtual host, it uses the configuration directives
5023 enclosed in the <code class="directive"><VirtualHost></code>
5024 section. <var>Addr</var> can be any of the following, optionally followed by
5025 a colon and a port number (or *):</p>
5028 <li>The IP address of the virtual host;</li>
5030 <li>A fully qualified domain name for the IP address of the
5031 virtual host (not recommended);</li>
5033 <li>The character <code>*</code>, which acts as a wildcard and matches
5034 any IP address.</li>
5036 <li>The string <code>_default_</code>, which is an alias for <code>*</code></li>
5040 <pre class="prettyprint lang-config"><VirtualHost 10.1.2.3:80>
5041 ServerAdmin webmaster@host.example.com
5042 DocumentRoot "/www/docs/host.example.com"
5043 ServerName host.example.com
5044 ErrorLog "logs/host.example.com-error_log"
5045 TransferLog "logs/host.example.com-access_log"
5046 </VirtualHost></pre>
5050 <p>IPv6 addresses must be specified in square brackets because
5051 the optional port number could not be determined otherwise. An
5052 IPv6 example is shown below:</p>
5054 <pre class="prettyprint lang-config"><VirtualHost [2001:db8::a00:20ff:fea7:ccea]:80>
5055 ServerAdmin webmaster@host.example.com
5056 DocumentRoot "/www/docs/host.example.com"
5057 ServerName host.example.com
5058 ErrorLog "logs/host.example.com-error_log"
5059 TransferLog "logs/host.example.com-access_log"
5060 </VirtualHost></pre>
5063 <p>Each Virtual Host must correspond to a different IP address,
5064 different port number, or a different host name for the server,
5065 in the former case the server machine must be configured to
5066 accept IP packets for multiple addresses. (If the machine does
5067 not have multiple network interfaces, then this can be
5068 accomplished with the <code>ifconfig alias</code> command -- if
5069 your OS supports it).</p>
5071 <div class="note"><h3>Note</h3>
5072 <p>The use of <code class="directive"><VirtualHost></code> does
5073 <strong>not</strong> affect what addresses Apache httpd listens on. You
5074 may need to ensure that Apache httpd is listening on the correct addresses
5075 using <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>.</p>
5078 <p>A <code class="directive"><a href="#servername">ServerName</a></code> should be
5079 specified inside each <code class="directive"><VirtualHost></code> block. If it is absent, the
5080 <code class="directive"><a href="#servername">ServerName</a></code> from the "main"
5081 server configuration will be inherited.</p>
5083 <p>When a request is received, the server first maps it to the best matching
5084 <code class="directive"><VirtualHost></code> based on the local
5085 IP address and port combination only. Non-wildcards have a higher
5086 precedence. If no match based on IP and port occurs at all, the
5087 "main" server configuration is used.</p>
5089 <p>If multiple virtual hosts contain the best matching IP address and port,
5090 the server selects from these virtual hosts the best match based on the
5091 requested hostname. If no matching name-based virtual host is found,
5092 then the first listed virtual host that matched the IP address will be
5093 used. As a consequence, the first listed virtual host for a given IP address
5094 and port combination is the default virtual host for that IP and port
5097 <div class="warning"><h3>Security</h3>
5098 <p>See the <a href="../misc/security_tips.html">security tips</a>
5099 document for details on why your security could be compromised if the
5100 directory where log files are stored is writable by anyone other
5101 than the user that starts the server.</p>
5106 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
5107 <li><a href="../dns-caveats.html">Issues Regarding DNS and
5108 Apache HTTP Server</a></li>
5109 <li><a href="../bind.html">Setting
5110 which addresses and ports Apache HTTP Server uses</a></li>
5111 <li><a href="../sections.html">How <Directory>, <Location>
5112 and <Files> sections work</a> for an explanation of how these
5113 different sections are combined when a request is received</li>
5116 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
5117 <div class="directive-section"><h2><a name="Warning" id="Warning">Warning</a> <a name="warning" id="warning">Directive</a></h2>
5118 <table class="directive">
5119 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Warn from configuration parsing with a custom message</td></tr>
5120 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Warning <var>message</var></code></td></tr>
5121 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
5122 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
5123 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
5124 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
5125 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.5 and later</td></tr>
5127 <p>If an issue can be detected from within the configuration, this
5128 directive can be used to generate a custom warning message. The
5129 configuration parsing is not halted. The typical use is to check
5130 whether some user define options are set, and warn if not.</p>
5132 <pre class="prettyprint lang-config"># Example
5133 # tell when ReverseProxy is not set
5134 <IfDefine !ReverseProxy>
5135 Warning "reverse proxy is not started, hope this is okay!"
5138 <IfDefine ReverseProxy>
5139 # define custom proxy configuration
5140 </IfDefine></pre>
5146 <div class="bottomlang">
5147 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
5148 <a href="../en/mod/core.html" title="English"> en </a> |
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5153 </div><div class="top"><a href="#page-header"><img src="../images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Comments</a></h2><div class="warning"><strong>Notice:</strong><br />This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed again by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Freenode, or sent to our <a href="http://httpd.apache.org/lists.html">mailing lists</a>.</div>
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