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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> |
30 <a href="../en/mod/core.html" title="English"> en </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="#iffile"><IfFile></a></li>
79 <li><img alt="" src="../images/down.gif" /> <a href="#ifmodule"><IfModule></a></li>
80 <li><img alt="" src="../images/down.gif" /> <a href="#include">Include</a></li>
81 <li><img alt="" src="../images/down.gif" /> <a href="#includeoptional">IncludeOptional</a></li>
82 <li><img alt="" src="../images/down.gif" /> <a href="#keepalive">KeepAlive</a></li>
83 <li><img alt="" src="../images/down.gif" /> <a href="#keepalivetimeout">KeepAliveTimeout</a></li>
84 <li><img alt="" src="../images/down.gif" /> <a href="#limit"><Limit></a></li>
85 <li><img alt="" src="../images/down.gif" /> <a href="#limitexcept"><LimitExcept></a></li>
86 <li><img alt="" src="../images/down.gif" /> <a href="#limitinternalrecursion">LimitInternalRecursion</a></li>
87 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestbody">LimitRequestBody</a></li>
88 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfields">LimitRequestFields</a></li>
89 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfieldsize">LimitRequestFieldSize</a></li>
90 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestline">LimitRequestLine</a></li>
91 <li><img alt="" src="../images/down.gif" /> <a href="#limitxmlrequestbody">LimitXMLRequestBody</a></li>
92 <li><img alt="" src="../images/down.gif" /> <a href="#location"><Location></a></li>
93 <li><img alt="" src="../images/down.gif" /> <a href="#locationmatch"><LocationMatch></a></li>
94 <li><img alt="" src="../images/down.gif" /> <a href="#loglevel">LogLevel</a></li>
95 <li><img alt="" src="../images/down.gif" /> <a href="#logleveloverride">LogLevelOverride</a></li>
96 <li><img alt="" src="../images/down.gif" /> <a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></li>
97 <li><img alt="" src="../images/down.gif" /> <a href="#maxrangeoverlaps">MaxRangeOverlaps</a></li>
98 <li><img alt="" src="../images/down.gif" /> <a href="#maxrangereversals">MaxRangeReversals</a></li>
99 <li><img alt="" src="../images/down.gif" /> <a href="#maxranges">MaxRanges</a></li>
100 <li><img alt="" src="../images/down.gif" /> <a href="#mergetrailers">MergeTrailers</a></li>
101 <li><img alt="" src="../images/down.gif" /> <a href="#mutex">Mutex</a></li>
102 <li><img alt="" src="../images/down.gif" /> <a href="#namevirtualhost">NameVirtualHost</a></li>
103 <li><img alt="" src="../images/down.gif" /> <a href="#options">Options</a></li>
104 <li><img alt="" src="../images/down.gif" /> <a href="#protocol">Protocol</a></li>
105 <li><img alt="" src="../images/down.gif" /> <a href="#protocols">Protocols</a></li>
106 <li><img alt="" src="../images/down.gif" /> <a href="#protocolshonororder">ProtocolsHonorOrder</a></li>
107 <li><img alt="" src="../images/down.gif" /> <a href="#qualifyredirecturl">QualifyRedirectURL</a></li>
108 <li><img alt="" src="../images/down.gif" /> <a href="#registerhttpmethod">RegisterHttpMethod</a></li>
109 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitcpu">RLimitCPU</a></li>
110 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitmem">RLimitMEM</a></li>
111 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitnproc">RLimitNPROC</a></li>
112 <li><img alt="" src="../images/down.gif" /> <a href="#scriptinterpretersource">ScriptInterpreterSource</a></li>
113 <li><img alt="" src="../images/down.gif" /> <a href="#seerequesttail">SeeRequestTail</a></li>
114 <li><img alt="" src="../images/down.gif" /> <a href="#serveradmin">ServerAdmin</a></li>
115 <li><img alt="" src="../images/down.gif" /> <a href="#serveralias">ServerAlias</a></li>
116 <li><img alt="" src="../images/down.gif" /> <a href="#servername">ServerName</a></li>
117 <li><img alt="" src="../images/down.gif" /> <a href="#serverpath">ServerPath</a></li>
118 <li><img alt="" src="../images/down.gif" /> <a href="#serverroot">ServerRoot</a></li>
119 <li><img alt="" src="../images/down.gif" /> <a href="#serversignature">ServerSignature</a></li>
120 <li><img alt="" src="../images/down.gif" /> <a href="#servertokens">ServerTokens</a></li>
121 <li><img alt="" src="../images/down.gif" /> <a href="#sethandler">SetHandler</a></li>
122 <li><img alt="" src="../images/down.gif" /> <a href="#setinputfilter">SetInputFilter</a></li>
123 <li><img alt="" src="../images/down.gif" /> <a href="#setoutputfilter">SetOutputFilter</a></li>
124 <li><img alt="" src="../images/down.gif" /> <a href="#timeout">TimeOut</a></li>
125 <li><img alt="" src="../images/down.gif" /> <a href="#traceenable">TraceEnable</a></li>
126 <li><img alt="" src="../images/down.gif" /> <a href="#undefine">UnDefine</a></li>
127 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalname">UseCanonicalName</a></li>
128 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></li>
129 <li><img alt="" src="../images/down.gif" /> <a href="#virtualhost"><VirtualHost></a></li>
130 <li><img alt="" src="../images/down.gif" /> <a href="#warning">Warning</a></li>
132 <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>
134 <li><a href="#comments_section">Comments</a></li></ul></div>
136 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
137 <div class="directive-section"><h2><a name="AcceptFilter" id="AcceptFilter">AcceptFilter</a> <a name="acceptfilter" id="acceptfilter">Directive</a></h2>
138 <table class="directive">
139 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures optimizations for a Protocol's Listener Sockets</td></tr>
140 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptFilter <var>protocol</var> <var>accept_filter</var></code></td></tr>
141 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
142 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
143 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
145 <p>This directive enables operating system specific optimizations for a
146 listening socket by the <code class="directive">Protocol</code> type.
147 The basic premise is for the kernel to not send a socket to the server
148 process until either data is received or an entire HTTP Request is buffered.
149 Only <a href="http://www.freebsd.org/cgi/man.cgi?query=accept_filter&sektion=9">
150 FreeBSD's Accept Filters</a>, Linux's more primitive
151 <code>TCP_DEFER_ACCEPT</code>, and Windows' optimized AcceptEx()
152 are currently supported.</p>
154 <p>Using <code>none</code> for an argument will disable any accept filters
155 for that protocol. This is useful for protocols that require a server
156 send data first, such as <code>ftp:</code> or <code>nntp</code>:</p>
157 <pre class="prettyprint lang-config">AcceptFilter nntp none</pre>
160 <p>The default protocol names are <code>https</code> for port 443
161 and <code>http</code> for all other ports. To specify that another
162 protocol is being used with a listening port, add the <var>protocol</var>
163 argument to the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>
166 <p>The default values on FreeBSD are:</p>
167 <pre class="prettyprint lang-config">AcceptFilter http httpready
168 AcceptFilter https dataready</pre>
171 <p>The <code>httpready</code> accept filter buffers entire HTTP requests at
172 the kernel level. Once an entire request is received, the kernel then
173 sends it to the server. See the
174 <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_http&sektion=9">
175 accf_http(9)</a> man page for more details. Since HTTPS requests are
176 encrypted, only the <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_data&sektion=9">
177 accf_data(9)</a> filter is used.</p>
179 <p>The default values on Linux are:</p>
180 <pre class="prettyprint lang-config">AcceptFilter http data
181 AcceptFilter https data</pre>
184 <p>Linux's <code>TCP_DEFER_ACCEPT</code> does not support buffering http
185 requests. Any value besides <code>none</code> will enable
186 <code>TCP_DEFER_ACCEPT</code> on that listener. For more details
188 <a href="http://man7.org/linux/man-pages/man7/tcp.7.html">
189 tcp(7)</a> man page.</p>
191 <p>The default values on Windows are:</p>
192 <pre class="prettyprint lang-config">AcceptFilter http connect
193 AcceptFilter https connect</pre>
196 <p>Window's mpm_winnt interprets the AcceptFilter to toggle the AcceptEx()
197 API, and does not support http protocol buffering. <code>connect</code>
198 will use the AcceptEx() API, also retrieve the network endpoint
199 addresses, but like <code>none</code> the <code>connect</code> option
200 does not wait for the initial data transmission.</p>
202 <p>On Windows, <code>none</code> uses accept() rather than AcceptEx()
203 and will not recycle sockets between connections. This is useful for
204 network adapters with broken driver support, as well as some virtual
205 network providers such as vpn drivers, or spam, virus or spyware
208 <div class="warning">
209 <h3>The <code>data</code> AcceptFilter (Windows)</h3>
211 <p>For versions 2.4.23 and prior, the Windows <code>data</code> accept
212 filter waited until data had been transmitted and the initial data
213 buffer and network endpoint addresses had been retrieved from the
214 single AcceptEx() invocation. This implementation was subject to a
215 denial of service attack and has been disabled.</p>
217 <p>Current releases of httpd default to the <code>connect</code> filter
218 on Windows, and will fall back to <code>connect</code> if
219 <code>data</code> is specified. Users of prior releases are encouraged
220 to add an explicit setting of <code>connect</code> for their
221 AcceptFilter, as shown above.</p>
227 <li><code class="directive"><a href="#protocol">Protocol</a></code></li>
230 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
231 <div class="directive-section"><h2><a name="AcceptPathInfo" id="AcceptPathInfo">AcceptPathInfo</a> <a name="acceptpathinfo" id="acceptpathinfo">Directive</a></h2>
232 <table class="directive">
233 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Resources accept trailing pathname information</td></tr>
234 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptPathInfo On|Off|Default</code></td></tr>
235 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AcceptPathInfo Default</code></td></tr>
236 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
237 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
238 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
239 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
242 <p>This directive controls whether requests that contain trailing
243 pathname information that follows an actual filename (or
244 non-existent file in an existing directory) will be accepted or
245 rejected. The trailing pathname information can be made
246 available to scripts in the <code>PATH_INFO</code> environment
249 <p>For example, assume the location <code>/test/</code> points to
250 a directory that contains only the single file
251 <code>here.html</code>. Then requests for
252 <code>/test/here.html/more</code> and
253 <code>/test/nothere.html/more</code> both collect
254 <code>/more</code> as <code>PATH_INFO</code>.</p>
256 <p>The three possible arguments for the
257 <code class="directive">AcceptPathInfo</code> directive are:</p>
259 <dt><code>Off</code></dt><dd>A request will only be accepted if it
260 maps to a literal path that exists. Therefore a request with
261 trailing pathname information after the true filename such as
262 <code>/test/here.html/more</code> in the above example will return
263 a 404 NOT FOUND error.</dd>
265 <dt><code>On</code></dt><dd>A request will be accepted if a
266 leading path component maps to a file that exists. The above
267 example <code>/test/here.html/more</code> will be accepted if
268 <code>/test/here.html</code> maps to a valid file.</dd>
270 <dt><code>Default</code></dt><dd>The treatment of requests with
271 trailing pathname information is determined by the <a href="../handler.html">handler</a> responsible for the request.
272 The core handler for normal files defaults to rejecting
273 <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
274 <code>PATH_INFO</code> by default.</dd>
277 <p>The primary purpose of the <code>AcceptPathInfo</code>
278 directive is to allow you to override the handler's choice of
279 accepting or rejecting <code>PATH_INFO</code>. This override is required,
280 for example, when you use a <a href="../filter.html">filter</a>, such
281 as <a href="mod_include.html">INCLUDES</a>, to generate content
282 based on <code>PATH_INFO</code>. The core handler would usually reject
283 the request, so you can use the following configuration to enable
286 <pre class="prettyprint lang-config"><Files "mypaths.shtml">
288 SetOutputFilter INCLUDES
295 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
296 <div class="directive-section"><h2><a name="AccessFileName" id="AccessFileName">AccessFileName</a> <a name="accessfilename" id="accessfilename">Directive</a></h2>
297 <table class="directive">
298 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Name of the distributed configuration file</td></tr>
299 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AccessFileName <var>filename</var> [<var>filename</var>] ...</code></td></tr>
300 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AccessFileName .htaccess</code></td></tr>
301 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
302 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
303 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
305 <p>While processing a request, the server looks for
306 the first existing configuration file from this list of names in
307 every directory of the path to the document, if distributed
308 configuration files are <a href="#allowoverride">enabled for that
309 directory</a>. For example:</p>
311 <pre class="prettyprint lang-config">AccessFileName .acl</pre>
314 <p>Before returning the document
315 <code>/usr/local/web/index.html</code>, the server will read
316 <code>/.acl</code>, <code>/usr/.acl</code>,
317 <code>/usr/local/.acl</code> and <code>/usr/local/web/.acl</code>
318 for directives unless they have been disabled with:</p>
320 <pre class="prettyprint lang-config"><Directory "/">
322 </Directory></pre>
327 <li><code class="directive"><a href="#allowoverride">AllowOverride</a></code></li>
328 <li><a href="../configuring.html">Configuration Files</a></li>
329 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
332 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
333 <div class="directive-section"><h2><a name="AddDefaultCharset" id="AddDefaultCharset">AddDefaultCharset</a> <a name="adddefaultcharset" id="adddefaultcharset">Directive</a></h2>
334 <table class="directive">
335 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Default charset parameter to be added when a response
336 content-type is <code>text/plain</code> or <code>text/html</code></td></tr>
337 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AddDefaultCharset On|Off|<var>charset</var></code></td></tr>
338 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AddDefaultCharset Off</code></td></tr>
339 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
340 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
341 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
342 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
344 <p>This directive specifies a default value for the media type
345 charset parameter (the name of a character encoding) to be added
346 to a response if and only if the response's content-type is either
347 <code>text/plain</code> or <code>text/html</code>. This should override
348 any charset specified in the body of the response via a <code>META</code>
349 element, though the exact behavior is often dependent on the user's client
350 configuration. A setting of <code>AddDefaultCharset Off</code>
351 disables this functionality. <code>AddDefaultCharset On</code> enables
352 a default charset of <code>iso-8859-1</code>. Any other value is assumed
353 to be the <var>charset</var> to be used, which should be one of the
354 <a href="http://www.iana.org/assignments/character-sets">IANA registered
355 charset values</a> for use in Internet media types (MIME types).
358 <pre class="prettyprint lang-config">AddDefaultCharset utf-8</pre>
361 <p><code class="directive">AddDefaultCharset</code> should only be used when all
362 of the text resources to which it applies are known to be in that
363 character encoding and it is too inconvenient to label their charset
364 individually. One such example is to add the charset parameter
365 to resources containing generated content, such as legacy CGI
366 scripts, that might be vulnerable to cross-site scripting attacks
367 due to user-provided data being included in the output. Note, however,
368 that a better solution is to just fix (or delete) those scripts, since
369 setting a default charset does not protect users that have enabled
370 the "auto-detect character encoding" feature on their browser.</p>
374 <li><code class="directive"><a href="../mod/mod_mime.html#addcharset">AddCharset</a></code></li>
377 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
378 <div class="directive-section"><h2><a name="AllowEncodedSlashes" id="AllowEncodedSlashes">AllowEncodedSlashes</a> <a name="allowencodedslashes" id="allowencodedslashes">Directive</a></h2>
379 <table class="directive">
380 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines whether encoded path separators in URLs are allowed to
381 be passed through</td></tr>
382 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowEncodedSlashes On|Off|NoDecode</code></td></tr>
383 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowEncodedSlashes Off</code></td></tr>
384 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
385 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
386 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
387 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>
388 NoDecode option available in 2.3.12 and later.</td></tr>
390 <p>The <code class="directive">AllowEncodedSlashes</code> directive allows URLs
391 which contain encoded path separators (<code>%2F</code> for <code>/</code>
392 and additionally <code>%5C</code> for <code>\</code> on accordant systems)
393 to be used in the path info.</p>
395 <p>With the default value, <code>Off</code>, such URLs are refused
396 with a 404 (Not found) error.</p>
398 <p>With the value <code>On</code>, such URLs are accepted, and encoded
399 slashes are decoded like all other encoded characters.</p>
401 <p>With the value <code>NoDecode</code>, such URLs are accepted, but
402 encoded slashes are not decoded but left in their encoded state.</p>
404 <p>Turning <code class="directive">AllowEncodedSlashes</code> <code>On</code> is
405 mostly useful when used in conjunction with <code>PATH_INFO</code>.</p>
407 <div class="note"><h3>Note</h3>
408 <p>If encoded slashes are needed in path info, use of <code>NoDecode</code> is
409 strongly recommended as a security measure. Allowing slashes
410 to be decoded could potentially allow unsafe paths.</p>
415 <li><code class="directive"><a href="#acceptpathinfo">AcceptPathInfo</a></code></li>
418 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
419 <div class="directive-section"><h2><a name="AllowOverride" id="AllowOverride">AllowOverride</a> <a name="allowoverride" id="allowoverride">Directive</a></h2>
420 <table class="directive">
421 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Types of directives that are allowed in
422 <code>.htaccess</code> files</td></tr>
423 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowOverride All|None|<var>directive-type</var>
424 [<var>directive-type</var>] ...</code></td></tr>
425 <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>
426 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
427 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
428 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
430 <p>When the server finds an <code>.htaccess</code> file (as
431 specified by <code class="directive"><a href="#accessfilename">AccessFileName</a></code>),
432 it needs to know which directives declared in that file can override
433 earlier configuration directives.</p>
435 <div class="note"><h3>Only available in <Directory> sections</h3>
436 <code class="directive">AllowOverride</code> is valid only in
437 <code class="directive"><a href="#directory"><Directory></a></code>
438 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
439 <code class="directive"><a href="#files"><Files></a></code> sections.
442 <p>When this directive is set to <code>None</code> and <code class="directive"><a href="#allowoverridelist">AllowOverrideList</a></code> is set to
443 <code>None</code>, <a href="#accessfilename">.htaccess</a> files are
444 completely ignored. In this case, the server will not even attempt
445 to read <code>.htaccess</code> files in the filesystem.</p>
447 <p>When this directive is set to <code>All</code>, then any
448 directive which has the .htaccess <a href="directive-dict.html#Context">Context</a> is allowed in
449 <code>.htaccess</code> files.</p>
451 <p>The <var>directive-type</var> can be one of the following
452 groupings of directives.</p>
459 Allow use of the authorization directives (<code class="directive"><a href="../mod/mod_authz_dbm.html#authdbmgroupfile">AuthDBMGroupFile</a></code>,
460 <code class="directive"><a href="../mod/mod_authn_dbm.html#authdbmuserfile">AuthDBMUserFile</a></code>,
461 <code class="directive"><a href="../mod/mod_authz_groupfile.html#authgroupfile">AuthGroupFile</a></code>,
462 <code class="directive"><a href="../mod/mod_authn_core.html#authname">AuthName</a></code>,
463 <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>
468 Allow use of the directives controlling document types
469 (<code class="directive"><a href="#errordocument">ErrorDocument</a></code>,
470 <code class="directive"><a href="#forcetype">ForceType</a></code>,
471 <code class="directive"><a href="../mod/mod_negotiation.html#languagepriority">LanguagePriority</a></code>,
472 <code class="directive"><a href="#sethandler">SetHandler</a></code>,
473 <code class="directive"><a href="#setinputfilter">SetInputFilter</a></code>,
474 <code class="directive"><a href="#setoutputfilter">SetOutputFilter</a></code>, and
475 <code class="module"><a href="../mod/mod_mime.html">mod_mime</a></code> Add* and Remove* directives),
476 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>),
477 <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>),
478 <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
479 <code class="directive"><a href="../mod/mod_actions.html#action">Action</a></code> from
480 <code class="module"><a href="../mod/mod_actions.html">mod_actions</a></code>.
486 Allow use of the directives controlling directory indexing
487 (<code class="directive"><a href="../mod/mod_autoindex.html#adddescription">AddDescription</a></code>,
488 <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>,
489 <code class="directive"><a href="../mod/mod_autoindex.html#addiconbytype">AddIconByType</a></code>,
490 <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>,
496 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>
501 <dt>Nonfatal=[Override|Unknown|All]</dt>
504 Allow use of AllowOverride option to treat invalid (unrecognized
505 or disallowed) directives in
506 .htaccess as nonfatal. Instead of causing an Internal Server
507 Error, disallowed or unrecognised directives will be ignored
508 and a warning logged:
510 <li><strong>Nonfatal=Override</strong> treats directives
511 forbidden by AllowOverride as nonfatal.</li>
512 <li><strong>Nonfatal=Unknown</strong> treats unknown directives
513 as nonfatal. This covers typos and directives implemented
514 by a module that's not present.</li>
515 <li><strong>Nonfatal=All</strong> treats both the above as nonfatal.</li>
517 <p>Note that a syntax error in a valid directive will still cause
518 an Internal Server Error.</p>
519 <div class="warning"><h3>Security</h3>
520 Nonfatal errors may have security implications for .htaccess users.
521 For example, if AllowOverride disallows AuthConfig, users'
522 configuration designed to restrict access to a site will be disabled.
526 <dt>Options[=<var>Option</var>,...]</dt>
529 Allow use of the directives controlling specific directory
530 features (<code class="directive"><a href="#options">Options</a></code> and
531 <code class="directive"><a href="../mod/mod_include.html#xbithack">XBitHack</a></code>).
532 An equal sign may be given followed by a comma-separated list, without
533 spaces, of options that may be set using the <code class="directive"><a href="#options">Options</a></code> command.
535 <div class="note"><h3>Implicit disabling of Options</h3>
536 <p>Even though the list of options that may be used in .htaccess files
537 can be limited with this directive, as long as any <code class="directive"><a href="#options">Options</a></code> directive is allowed any
538 other inherited option can be disabled by using the non-relative
539 syntax. In other words, this mechanism cannot force a specific option
540 to remain <em>set</em> while allowing any others to be set.
543 <div class="example"><p><code>
544 AllowOverride Options=Indexes,MultiViews
551 <pre class="prettyprint lang-config">AllowOverride AuthConfig Indexes</pre>
554 <p>In the example above, all directives that are neither in the group
555 <code>AuthConfig</code> nor <code>Indexes</code> cause an internal
558 <div class="note"><p>For security and performance reasons, do not set
559 <code>AllowOverride</code> to anything other than <code>None</code>
560 in your <code><Directory "/"></code> block. Instead, find (or
561 create) the <code><Directory></code> block that refers to the
562 directory where you're actually planning to place a
563 <code>.htaccess</code> file.</p>
568 <li><code class="directive"><a href="#accessfilename">AccessFileName</a></code></li>
569 <li><code class="directive"><a href="#allowoverridelist">AllowOverrideList</a></code></li>
570 <li><a href="../configuring.html">Configuration Files</a></li>
571 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
574 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
575 <div class="directive-section"><h2><a name="AllowOverrideList" id="AllowOverrideList">AllowOverrideList</a> <a name="allowoverridelist" id="allowoverridelist">Directive</a></h2>
576 <table class="directive">
577 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Individual directives that are allowed in
578 <code>.htaccess</code> files</td></tr>
579 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowOverrideList None|<var>directive</var>
580 [<var>directive-type</var>] ...</code></td></tr>
581 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowOverrideList None</code></td></tr>
582 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
583 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
584 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
586 <p>When the server finds an <code>.htaccess</code> file (as
587 specified by <code class="directive"><a href="#accessfilename">AccessFileName</a></code>),
588 it needs to know which directives declared in that file can override
589 earlier configuration directives.</p>
591 <div class="note"><h3>Only available in <Directory> sections</h3>
592 <code class="directive">AllowOverrideList</code> is valid only in
593 <code class="directive"><a href="#directory"><Directory></a></code>
594 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
595 <code class="directive"><a href="#files"><Files></a></code> sections.
598 <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>,
599 then <a href="#accessfilename">.htaccess</a> files are completely
600 ignored. In this case, the server will not even attempt to read
601 <code>.htaccess</code> files in the filesystem.</p>
605 <pre class="prettyprint lang-config">AllowOverride None
606 AllowOverrideList Redirect RedirectMatch</pre>
609 <p>In the example above, only the <code>Redirect</code> and
610 <code>RedirectMatch</code> directives are allowed. All others will
611 cause an Internal Server Error.</p>
615 <pre class="prettyprint lang-config">AllowOverride AuthConfig
616 AllowOverrideList CookieTracking CookieName</pre>
619 <p>In the example above, <code class="directive"><a href="#allowoverride">AllowOverride
620 </a></code> grants permission to the <code>AuthConfig</code>
621 directive grouping and <code class="directive">AllowOverrideList</code> grants
622 permission to only two directives from the <code>FileInfo</code> directive
623 grouping. All others will cause an Internal Server Error.</p>
627 <li><code class="directive"><a href="#accessfilename">AccessFileName</a></code></li>
628 <li><code class="directive"><a href="#allowoverride">AllowOverride</a></code></li>
629 <li><a href="../configuring.html">Configuration Files</a></li>
630 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
633 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
634 <div class="directive-section"><h2><a name="AsyncFilter" id="AsyncFilter">AsyncFilter</a> <a name="asyncfilter" id="asyncfilter">Directive</a></h2>
635 <table class="directive">
636 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Set the minimum filter type eligible for asynchronous handling</td></tr>
637 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AsyncFilter request|connection|network</code></td></tr>
638 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AsyncFilter request</code></td></tr>
639 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
640 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
641 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
642 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Only available from Apache 2.5.0 and later.</td></tr>
644 <p>This directive controls the minimum filter levels that are eligible
645 for asynchronous handling. This may be necessary to support legacy external
646 filters that did not handle meta buckets correctly.</p>
648 <p>If set to "network", asynchronous handling will be limited to the network
649 filter only. If set to "connection", all connection and network filters
650 will be eligible for asynchronous handling, including <code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code>.
651 If set to "request", all filters will be eligible for asynchronous handling.</p>
654 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
655 <div class="directive-section"><h2><a name="CGIMapExtension" id="CGIMapExtension">CGIMapExtension</a> <a name="cgimapextension" id="cgimapextension">Directive</a></h2>
656 <table class="directive">
657 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
659 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CGIMapExtension <var>cgi-path</var> <var>.extension</var></code></td></tr>
660 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
661 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
662 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
663 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
664 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>NetWare only</td></tr>
666 <p>This directive is used to control how Apache httpd finds the
667 interpreter used to run CGI scripts. For example, setting
668 <code>CGIMapExtension sys:\foo.nlm .foo</code> will
669 cause all CGI script files with a <code>.foo</code> extension to
670 be passed to the FOO interpreter.</p>
673 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
674 <div class="directive-section"><h2><a name="CGIPassAuth" id="CGIPassAuth">CGIPassAuth</a> <a name="cgipassauth" id="cgipassauth">Directive</a></h2>
675 <table class="directive">
676 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables passing HTTP authorization headers to scripts as CGI
678 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CGIPassAuth On|Off</code></td></tr>
679 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>CGIPassAuth Off</code></td></tr>
680 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
681 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig</td></tr>
682 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
683 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
684 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.4.13 and later</td></tr>
686 <p><code class="directive">CGIPassAuth</code> allows scripts access to HTTP
687 authorization headers such as <code>Authorization</code>, which is
688 required for scripts that implement HTTP Basic authentication.
689 Normally these HTTP headers are hidden from scripts. This is to disallow
690 scripts from seeing user ids and passwords used to access the server when
691 HTTP Basic authentication is enabled in the web server. This directive
692 should be used when scripts are allowed to implement HTTP Basic
695 <p>This directive can be used instead of the compile-time setting
696 <code>SECURITY_HOLE_PASS_AUTHORIZATION</code> which has been available
697 in previous versions of Apache HTTP Server.</p>
699 <p>The setting is respected by any modules which use
700 <code>ap_add_common_vars()</code>, such as <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>,
701 <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>,
702 <code class="module"><a href="../mod/mod_proxy_scgi.html">mod_proxy_scgi</a></code>, and so on. Notably, it affects
703 modules which don't handle the request in the usual sense but
704 still use this API; examples of this are <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
705 and <code class="module"><a href="../mod/mod_ext_filter.html">mod_ext_filter</a></code>. Third-party modules that don't
706 use <code>ap_add_common_vars()</code> may choose to respect the setting
710 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
711 <div class="directive-section"><h2><a name="CGIVar" id="CGIVar">CGIVar</a> <a name="cgivar" id="cgivar">Directive</a></h2>
712 <table class="directive">
713 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Controls how some CGI variables are set</td></tr>
714 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CGIVar <var>variable</var> <var>rule</var></code></td></tr>
715 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
716 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
717 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
718 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
719 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.4.21 and later</td></tr>
721 <p>This directive controls how some CGI variables are set.</p>
723 <p><strong>REQUEST_URI</strong> rules:</p>
725 <dt><code>original-uri</code> (default)</dt>
726 <dd>The value is taken from the original request line, and will not
727 reflect internal redirects or subrequests which change the requested
729 <dt><code>current-uri</code></dt>
730 <dd>The value reflects the resource currently being processed,
731 which may be different than the original request from the client
732 due to internal redirects or subrequests.</dd>
736 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
737 <div class="directive-section"><h2><a name="ContentDigest" id="ContentDigest">ContentDigest</a> <a name="contentdigest" id="contentdigest">Directive</a></h2>
738 <table class="directive">
739 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables the generation of <code>Content-MD5</code> HTTP Response
741 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ContentDigest On|Off</code></td></tr>
742 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ContentDigest Off</code></td></tr>
743 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
744 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
745 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
746 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
748 <p>This directive enables the generation of
749 <code>Content-MD5</code> headers as defined in RFC1864
750 respectively RFC2616.</p>
752 <p>MD5 is an algorithm for computing a "message digest"
753 (sometimes called "fingerprint") of arbitrary-length data, with
754 a high degree of confidence that any alterations in the data
755 will be reflected in alterations in the message digest.</p>
757 <p>The <code>Content-MD5</code> header provides an end-to-end
758 message integrity check (MIC) of the entity-body. A proxy or
759 client may check this header for detecting accidental
760 modification of the entity-body in transit. Example header:</p>
762 <div class="example"><p><code>
763 Content-MD5: AuLb7Dp1rqtRtxz2m9kRpA==
766 <p>Note that this can cause performance problems on your server
767 since the message digest is computed on every request (the
768 values are not cached).</p>
770 <p><code>Content-MD5</code> is only sent for documents served
771 by the <code class="module"><a href="../mod/core.html">core</a></code>, and not by any module. For example,
772 SSI documents, output from CGI scripts, and byte range responses
773 do not have this header.</p>
776 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
777 <div class="directive-section"><h2><a name="DefaultRuntimeDir" id="DefaultRuntimeDir">DefaultRuntimeDir</a> <a name="defaultruntimedir" id="defaultruntimedir">Directive</a></h2>
778 <table class="directive">
779 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server run-time files</td></tr>
780 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultRuntimeDir <var>directory-path</var></code></td></tr>
781 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultRuntimeDir DEFAULT_REL_RUNTIMEDIR (logs/)</code></td></tr>
782 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
783 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
784 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
785 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.4.2 and later</td></tr>
787 <p>The <code class="directive">DefaultRuntimeDir</code> directive sets the
788 directory in which the server will create various run-time files
789 (shared memory, locks, etc.). If set as a relative path, the full path
790 will be relative to <code class="directive">ServerRoot</code>.</p>
792 <p><strong>Example</strong></p>
793 <pre class="prettyprint lang-config">DefaultRuntimeDir scratch/</pre>
796 <p>The default location of <code class="directive">DefaultRuntimeDir</code> may be
797 modified by changing the <code>DEFAULT_REL_RUNTIMEDIR</code> #define
800 <p>Note: <code class="directive">ServerRoot</code> should be specified before this
801 directive is used. Otherwise, the default value of <code class="directive">ServerRoot</code>
802 would be used to set the base directory.</p>
807 <li><a href="../misc/security_tips.html#serverroot">the
808 security tips</a> for information on how to properly set
809 permissions on the <code class="directive">ServerRoot</code></li>
812 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
813 <div class="directive-section"><h2><a name="DefaultType" id="DefaultType">DefaultType</a> <a name="defaulttype" id="defaulttype">Directive</a></h2>
814 <table class="directive">
815 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>This directive has no effect other than to emit warnings
816 if the value is not <code>none</code>. In prior versions, DefaultType
817 would specify a default media type to assign to response content for
818 which no other media type configuration could be found.
820 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultType <var>media-type|none</var></code></td></tr>
821 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultType none</code></td></tr>
822 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
823 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
824 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
825 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
826 <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.
829 <p>This directive has been disabled. For backwards compatibility
830 of configuration files, it may be specified with the value
831 <code>none</code>, meaning no default media type. For example:</p>
833 <pre class="prettyprint lang-config">DefaultType None</pre>
836 <p><code>DefaultType None</code> is only available in
837 httpd-2.2.7 and later.</p>
839 <p>Use the mime.types configuration file and the
840 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code> to configure media
841 type assignments via file extensions, or the
842 <code class="directive"><a href="#forcetype">ForceType</a></code> directive to configure
843 the media type for specific resources. Otherwise, the server will
844 send the response without a Content-Type header field and the
845 recipient may attempt to guess the media type.</p>
849 <li><code class="directive"><a href="#undefine">UnDefine</a></code></li>
850 <li><code class="directive"><a href="#ifdefine">IfDefine</a></code></li>
853 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
854 <div class="directive-section"><h2><a name="Define" id="Define">Define</a> <a name="define" id="define">Directive</a></h2>
855 <table class="directive">
856 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Define a variable</td></tr>
857 <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>
858 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
859 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
860 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
862 <p>In its one parameter form, <code class="directive">Define</code> is equivalent
863 to passing the <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>. It
864 can be used to toggle the use of
865 <code class="directive"><a href="#ifdefine"><IfDefine></a></code> sections
866 without needing to alter <code>-D</code> arguments in any startup
869 <p>In addition to that, if the second parameter is given, a config variable
870 is set to this value. The variable can be used in the configuration using
871 the <code>${VAR}</code> syntax. The variable is always globally defined
872 and not limited to the scope of the surrounding config section.</p>
874 <pre class="prettyprint lang-config"><IfDefine TEST>
875 Define servername test.example.com
877 <IfDefine !TEST>
878 Define servername www.example.com
882 DocumentRoot "/var/www/${servername}/htdocs"</pre>
885 <p>Variable names may not contain colon ":" characters, to avoid clashes
886 with <code class="directive"><a href="../mod/mod_rewrite.html#rewritemap">RewriteMap</a></code>'s syntax.</p>
888 <p>While this directive is supported in virtual host context,
889 the changes it makes are visible to any later configuration
890 directives, beyond any enclosing virtual host</p>
893 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
894 <div class="directive-section"><h2><a name="Directory" id="Directory"><Directory></a> <a name="directory" id="directory">Directive</a></h2>
895 <table class="directive">
896 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose a group of directives that apply only to the
897 named file-system directory, sub-directories, and their contents.</td></tr>
898 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Directory <var>directory-path</var>>
899 ... </Directory></code></td></tr>
900 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
901 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
902 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
904 <p><code class="directive"><Directory></code> and
905 <code></Directory></code> are used to enclose a group of
906 directives that will apply only to the named directory,
907 sub-directories of that directory, and the files within the respective
908 directories. Any directive that is allowed
909 in a directory context may be used. <var>Directory-path</var> is
910 either the full path to a directory, or a wild-card string using
911 Unix shell-style matching. In a wild-card string, <code>?</code> matches
912 any single character, and <code>*</code> matches any sequences of
913 characters. You may also use <code>[]</code> character ranges. None
914 of the wildcards match a `/' character, so <code><Directory
915 "/*/public_html"></code> will not match
916 <code>/home/user/public_html</code>, but <code><Directory
917 "/home/*/public_html"></code> will match. Example:</p>
919 <pre class="prettyprint lang-config"><Directory "/usr/local/httpd/htdocs">
920 Options Indexes FollowSymLinks
921 </Directory></pre>
924 <p>Directory paths <em>may</em> be quoted, if you like, however, it
925 <em>must</em> be quoted if the path contains spaces. This is because a
926 space would otherwise indicate the end of an argument.</p>
929 <p>Be careful with the <var>directory-path</var> arguments:
930 They have to literally match the filesystem path which Apache httpd uses
931 to access the files. Directives applied to a particular
932 <code><Directory></code> will not apply to files accessed from
933 that same directory via a different path, such as via different symbolic
937 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular
938 expressions</a> can also be used, with the addition of the
939 <code>~</code> character. For example:</p>
941 <pre class="prettyprint lang-config"><Directory ~ "^/www/[0-9]{3}">
943 </Directory></pre>
946 <p>would match directories in <code>/www/</code> that consisted of
949 <p>If multiple (non-regular expression) <code class="directive"><Directory></code> sections
950 match the directory (or one of its parents) containing a document,
951 then the directives are applied in the order of shortest match
952 first, interspersed with the directives from the <a href="#accessfilename">.htaccess</a> files. For example,
955 <pre class="prettyprint lang-config"><Directory "/">
959 <Directory "/home">
960 AllowOverride FileInfo
961 </Directory></pre>
964 <p>for access to the document <code>/home/web/dir/doc.html</code>
968 <li>Apply directive <code>AllowOverride None</code>
969 (disabling <code>.htaccess</code> files).</li>
971 <li>Apply directive <code>AllowOverride FileInfo</code> (for
972 directory <code>/home</code>).</li>
974 <li>Apply any <code>FileInfo</code> directives in
975 <code>/home/.htaccess</code>, <code>/home/web/.htaccess</code> and
976 <code>/home/web/dir/.htaccess</code> in that order.</li>
979 <p>Regular expressions are not considered until after all of the
980 normal sections have been applied. Then all of the regular
981 expressions are tested in the order they appeared in the
982 configuration file. For example, with</p>
984 <pre class="prettyprint lang-config"><Directory ~ "abc$">
985 # ... directives here ...
986 </Directory></pre>
989 <p>the regular expression section won't be considered until after
990 all normal <code class="directive"><Directory></code>s and
991 <code>.htaccess</code> files have been applied. Then the regular
992 expression will match on <code>/home/abc/public_html/abc</code> and
993 the corresponding <code class="directive"><Directory></code> will
996 <p><strong>Note that the default access for
997 <code><Directory "/"></code> is to permit all access.
998 This means that Apache httpd will serve any file mapped from an URL. It is
999 recommended that you change this with a block such
1002 <pre class="prettyprint lang-config"><Directory "/">
1004 </Directory></pre>
1007 <p><strong>and then override this for directories you
1008 <em>want</em> accessible. See the <a href="../misc/security_tips.html">Security Tips</a> page for more
1009 details.</strong></p>
1011 <p>The directory sections occur in the <code>httpd.conf</code> file.
1012 <code class="directive"><Directory></code> directives
1013 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>
1017 <li><a href="../sections.html">How <Directory>,
1018 <Location> and <Files> sections work</a> for an
1019 explanation of how these different sections are combined when a
1020 request is received</li>
1023 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1024 <div class="directive-section"><h2><a name="DirectoryMatch" id="DirectoryMatch"><DirectoryMatch></a> <a name="directorymatch" id="directorymatch">Directive</a></h2>
1025 <table class="directive">
1026 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose directives that apply to
1027 the contents of file-system directories matching a regular expression.</td></tr>
1028 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><DirectoryMatch <var>regex</var>>
1029 ... </DirectoryMatch></code></td></tr>
1030 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1031 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1032 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1034 <p><code class="directive"><DirectoryMatch></code> and
1035 <code></DirectoryMatch></code> are used to enclose a group
1036 of directives which will apply only to the named directory (and the files within),
1037 the same as <code class="directive"><a href="#directory"><Directory></a></code>.
1038 However, it takes as an argument a
1039 <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>. For example:</p>
1041 <pre class="prettyprint lang-config"><DirectoryMatch "^/www/(.+/)?[0-9]{3}/">
1043 </DirectoryMatch></pre>
1046 <p>matches directories in <code>/www/</code> (or any subdirectory thereof)
1047 that consist of three numbers.</p>
1049 <div class="note"><h3>Compatability</h3>
1050 Prior to 2.3.9, this directive implicitly applied to sub-directories
1051 (like <code class="directive"><a href="#directory"><Directory></a></code>) and
1052 could not match the end of line symbol ($). In 2.3.9 and later,
1053 only directories that match the expression are affected by the enclosed
1057 <div class="note"><h3>Trailing Slash</h3>
1058 This directive applies to requests for directories that may or may
1059 not end in a trailing slash, so expressions that are anchored to the
1060 end of line ($) must be written with care.
1063 <p>From 2.4.8 onwards, named groups and backreferences are captured and
1064 written to the environment with the corresponding name prefixed with
1065 "MATCH_" and in upper case. This allows elements of paths to be referenced
1066 from within <a href="../expr.html">expressions</a> and modules like
1067 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
1068 (unnamed) backreferences are ignored. Use named groups instead.</p>
1070 <pre class="prettyprint lang-config"><DirectoryMatch "^/var/www/combined/(?<sitename>[^/]+)">
1071 Require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
1072 </DirectoryMatch></pre>
1077 <li><code class="directive"><a href="#directory"><Directory></a></code> for
1078 a description of how regular expressions are mixed in with normal
1079 <code class="directive"><Directory></code>s</li>
1080 <li><a href="../sections.html">How <Directory>, <Location> and
1081 <Files> sections work</a> for an explanation of how these different
1082 sections are combined when a request is received</li>
1085 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1086 <div class="directive-section"><h2><a name="DocumentRoot" id="DocumentRoot">DocumentRoot</a> <a name="documentroot" id="documentroot">Directive</a></h2>
1087 <table class="directive">
1088 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory that forms the main document tree visible
1089 from the web</td></tr>
1090 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DocumentRoot <var>directory-path</var></code></td></tr>
1091 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DocumentRoot "/usr/local/apache/htdocs"</code></td></tr>
1092 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1093 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1094 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1096 <p>This directive sets the directory from which <code class="program"><a href="../programs/httpd.html">httpd</a></code>
1097 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
1098 path from the requested URL to the document root to make the
1099 path to the document. Example:</p>
1101 <pre class="prettyprint lang-config">DocumentRoot "/usr/web"</pre>
1104 <p>then an access to
1105 <code>http://my.example.com/index.html</code> refers to
1106 <code>/usr/web/index.html</code>. If the <var>directory-path</var> is
1107 not absolute then it is assumed to be relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1109 <p>The <code class="directive">DocumentRoot</code> should be specified without
1110 a trailing slash.</p>
1114 <li><a href="../urlmapping.html#documentroot">Mapping URLs to Filesystem
1118 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1119 <div class="directive-section"><h2><a name="Else" id="Else"><Else></a> <a name="else" id="else">Directive</a></h2>
1120 <table class="directive">
1121 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if the condition of a
1122 previous <code class="directive"><a href="#if"><If></a></code> or
1123 <code class="directive"><a href="#elseif"><ElseIf></a></code> section is not
1124 satisfied by a request at runtime</td></tr>
1125 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Else> ... </Else></code></td></tr>
1126 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1127 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1128 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1129 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1131 <p>The <code class="directive"><Else></code> applies the enclosed
1132 directives if and only if the most recent
1133 <code class="directive"><If></code> or
1134 <code class="directive"><ElseIf></code> section
1135 in the same scope has not been applied.
1136 For example: In </p>
1138 <pre class="prettyprint lang-config"><If "-z req('Host')">
1146 <p> The <code class="directive"><If></code> would match HTTP/1.0
1147 requests without a <var>Host:</var> header and the
1148 <code class="directive"><Else></code> would match requests
1149 with a <var>Host:</var> header.</p>
1154 <li><code class="directive"><a href="#if"><If></a></code></li>
1155 <li><code class="directive"><a href="#elseif"><ElseIf></a></code></li>
1156 <li><a href="../sections.html">How <Directory>, <Location>,
1157 <Files> sections work</a> for an explanation of how these
1158 different sections are combined when a request is received.
1159 <code class="directive"><If></code>,
1160 <code class="directive"><ElseIf></code>, and
1161 <code class="directive"><Else></code> are applied last.</li>
1164 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1165 <div class="directive-section"><h2><a name="ElseIf" id="ElseIf"><ElseIf></a> <a name="elseif" id="elseif">Directive</a></h2>
1166 <table class="directive">
1167 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is satisfied
1168 by a request at runtime while the condition of a previous
1169 <code class="directive"><a href="#if"><If></a></code> or
1170 <code class="directive"><ElseIf></code> section is not
1172 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><ElseIf <var>expression</var>> ... </ElseIf></code></td></tr>
1173 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1174 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1175 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1176 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1178 <p>The <code class="directive"><ElseIf></code> applies the enclosed
1179 directives if and only if both the given condition evaluates to true and
1180 the most recent <code class="directive"><If></code> or
1181 <code class="directive"><ElseIf></code> section in the same scope has
1182 not been applied. For example: In </p>
1184 <pre class="prettyprint lang-config"><If "-R '10.1.0.0/16'">
1187 <ElseIf "-R '10.0.0.0/8'">
1195 <p>The <code class="directive"><ElseIf></code> would match if
1196 the remote address of a request belongs to the subnet 10.0.0.0/8 but
1197 not to the subnet 10.1.0.0/16.</p>
1202 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
1203 for a complete reference and more examples.</li>
1204 <li><code class="directive"><a href="#if"><If></a></code></li>
1205 <li><code class="directive"><a href="#else"><Else></a></code></li>
1206 <li><a href="../sections.html">How <Directory>, <Location>,
1207 <Files> sections work</a> for an explanation of how these
1208 different sections are combined when a request is received.
1209 <code class="directive"><If></code>,
1210 <code class="directive"><ElseIf></code>, and
1211 <code class="directive"><Else></code> are applied last.</li>
1214 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1215 <div class="directive-section"><h2><a name="EnableMMAP" id="EnableMMAP">EnableMMAP</a> <a name="enablemmap" id="enablemmap">Directive</a></h2>
1216 <table class="directive">
1217 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use memory-mapping to read files during delivery</td></tr>
1218 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableMMAP On|Off</code></td></tr>
1219 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableMMAP On</code></td></tr>
1220 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1221 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1222 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1223 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1225 <p>This directive controls whether the <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use
1226 memory-mapping if it needs to read the contents of a file during
1227 delivery. By default, when the handling of a request requires
1228 access to the data within a file -- for example, when delivering a
1229 server-parsed file using <code class="module"><a href="../mod/mod_include.html">mod_include</a></code> -- Apache httpd
1230 memory-maps the file if the OS supports it.</p>
1232 <p>This memory-mapping sometimes yields a performance improvement.
1233 But in some environments, it is better to disable the memory-mapping
1234 to prevent operational problems:</p>
1237 <li>On some multiprocessor systems, memory-mapping can reduce the
1238 performance of the <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</li>
1239 <li>Deleting or truncating a file while <code class="program"><a href="../programs/httpd.html">httpd</a></code>
1240 has it memory-mapped can cause <code class="program"><a href="../programs/httpd.html">httpd</a></code> to
1241 crash with a segmentation fault.
1245 <p>For server configurations that are vulnerable to these problems,
1246 you should disable memory-mapping of delivered files by specifying:</p>
1248 <pre class="prettyprint lang-config">EnableMMAP Off</pre>
1251 <p>For NFS mounted files, this feature may be disabled explicitly for
1252 the offending files by specifying:</p>
1254 <pre class="prettyprint lang-config"><Directory "/path-to-nfs-files">
1256 </Directory></pre>
1260 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1261 <div class="directive-section"><h2><a name="EnableSendfile" id="EnableSendfile">EnableSendfile</a> <a name="enablesendfile" id="enablesendfile">Directive</a></h2>
1262 <table class="directive">
1263 <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>
1264 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableSendfile On|Off</code></td></tr>
1265 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableSendfile Off</code></td></tr>
1266 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1267 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1268 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1269 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1270 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Default changed to Off in
1271 version 2.3.9.</td></tr>
1273 <p>This directive controls whether <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use the
1274 sendfile support from the kernel to transmit file contents to the client.
1275 By default, when the handling of a request requires no access
1276 to the data within a file -- for example, when delivering a
1277 static file -- Apache httpd uses sendfile to deliver the file contents
1278 without ever reading the file if the OS supports it.</p>
1280 <p>This sendfile mechanism avoids separate read and send operations,
1281 and buffer allocations. But on some platforms or within some
1282 filesystems, it is better to disable this feature to avoid
1283 operational problems:</p>
1286 <li>Some platforms may have broken sendfile support that the build
1287 system did not detect, especially if the binaries were built on
1288 another box and moved to such a machine with broken sendfile
1290 <li>On Linux the use of sendfile triggers TCP-checksum
1291 offloading bugs on certain networking cards when using IPv6.</li>
1292 <li>On Linux on Itanium, <code>sendfile</code> may be unable to handle
1293 files over 2GB in size.</li>
1294 <li>With a network-mounted <code class="directive"><a href="#documentroot">DocumentRoot</a></code> (e.g., NFS, SMB, CIFS, FUSE),
1295 the kernel may be unable to serve the network file through
1299 <p>For server configurations that are not vulnerable to these problems,
1300 you may enable this feature by specifying:</p>
1302 <pre class="prettyprint lang-config">EnableSendfile On</pre>
1305 <p>For network mounted files, this feature may be disabled explicitly
1306 for the offending files by specifying:</p>
1308 <pre class="prettyprint lang-config"><Directory "/path-to-nfs-files">
1310 </Directory></pre>
1312 <p>Please note that the per-directory and .htaccess configuration
1313 of <code class="directive">EnableSendfile</code> is not supported by
1314 <code class="module"><a href="../mod/mod_cache_disk.html">mod_cache_disk</a></code>.
1315 Only global definition of <code class="directive">EnableSendfile</code>
1316 is taken into account by the module.
1320 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1321 <div class="directive-section"><h2><a name="Error" id="Error">Error</a> <a name="error" id="error">Directive</a></h2>
1322 <table class="directive">
1323 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Abort configuration parsing with a custom error message</td></tr>
1324 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Error <var>message</var></code></td></tr>
1325 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1326 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1327 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1328 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.3.9 and later</td></tr>
1330 <p>If an error can be detected within the configuration, this
1331 directive can be used to generate a custom error message, and halt
1332 configuration parsing. The typical use is for reporting required
1333 modules which are missing from the configuration.</p>
1335 <pre class="prettyprint lang-config"># Example
1336 # ensure that mod_include is loaded
1337 <IfModule !include_module>
1338 Error "mod_include is required by mod_foo. Load it with LoadModule."
1341 # ensure that exactly one of SSL,NOSSL is defined
1342 <IfDefine SSL>
1343 <IfDefine NOSSL>
1344 Error "Both SSL and NOSSL are defined. Define only one of them."
1347 <IfDefine !SSL>
1348 <IfDefine !NOSSL>
1349 Error "Either SSL or NOSSL must be defined."
1351 </IfDefine></pre>
1356 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1357 <div class="directive-section"><h2><a name="ErrorDocument" id="ErrorDocument">ErrorDocument</a> <a name="errordocument" id="errordocument">Directive</a></h2>
1358 <table class="directive">
1359 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>What the server will return to the client
1360 in case of an error</td></tr>
1361 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ErrorDocument <var>error-code</var> <var>document</var></code></td></tr>
1362 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1363 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1364 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1365 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1367 <p>In the event of a problem or error, Apache httpd can be configured
1368 to do one of four things,</p>
1371 <li>output a simple hardcoded error message</li>
1373 <li>output a customized message</li>
1375 <li>internally redirect to a local <var>URL-path</var> to handle the
1378 <li>redirect to an external <var>URL</var> to handle the
1382 <p>The first option is the default, while options 2-4 are
1383 configured using the <code class="directive">ErrorDocument</code>
1384 directive, which is followed by the HTTP response code and a URL
1385 or a message. Apache httpd will sometimes offer additional information
1386 regarding the problem/error.</p>
1388 <p>From 2.4.13, <a href="../expr.html">expression syntax</a> can be
1389 used inside the directive to produce dynamic strings and URLs.</p>
1391 <p>URLs can begin with a slash (/) for local web-paths (relative
1392 to the <code class="directive"><a href="#documentroot">DocumentRoot</a></code>), or be a
1393 full URL which the client can resolve. Alternatively, a message
1394 can be provided to be displayed by the browser. Note that deciding
1395 whether the parameter is an URL, a path or a message is performed
1396 before any expression is parsed. Examples:</p>
1398 <pre class="prettyprint lang-config">ErrorDocument 500 http://example.com/cgi-bin/server-error.cgi
1399 ErrorDocument 404 /errors/bad_urls.php
1400 ErrorDocument 401 /subscription_info.html
1401 ErrorDocument 403 "Sorry, can't allow you access today"
1402 ErrorDocument 403 Forbidden!
1403 ErrorDocument 403 /errors/forbidden.py?referrer=%{escape:%{HTTP_REFERER}}</pre>
1406 <p>Additionally, the special value <code>default</code> can be used
1407 to specify Apache httpd's simple hardcoded message. While not required
1408 under normal circumstances, <code>default</code> will restore
1409 Apache httpd's simple hardcoded message for configurations that would
1410 otherwise inherit an existing <code class="directive">ErrorDocument</code>.</p>
1412 <pre class="prettyprint lang-config">ErrorDocument 404 /cgi-bin/bad_urls.pl
1414 <Directory "/web/docs">
1415 ErrorDocument 404 default
1416 </Directory></pre>
1419 <p>Note that when you specify an <code class="directive">ErrorDocument</code>
1420 that points to a remote URL (ie. anything with a method such as
1421 <code>http</code> in front of it), Apache HTTP Server will send a redirect to the
1422 client to tell it where to find the document, even if the
1423 document ends up being on the same server. This has several
1424 implications, the most important being that the client will not
1425 receive the original error status code, but instead will
1426 receive a redirect status code. This in turn can confuse web
1427 robots and other clients which try to determine if a URL is
1428 valid using the status code. In addition, if you use a remote
1429 URL in an <code>ErrorDocument 401</code>, the client will not
1430 know to prompt the user for a password since it will not
1431 receive the 401 status code. Therefore, <strong>if you use an
1432 <code>ErrorDocument 401</code> directive, then it must refer to a local
1433 document.</strong></p>
1435 <p>Microsoft Internet Explorer (MSIE) will by default ignore
1436 server-generated error messages when they are "too small" and substitute
1437 its own "friendly" error messages. The size threshold varies depending on
1438 the type of error, but in general, if you make your error document
1439 greater than 512 bytes, then MSIE will show the server-generated
1440 error rather than masking it. More information is available in
1441 Microsoft Knowledge Base article <a href="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q294807">Q294807</a>.</p>
1443 <p>Although most error messages can be overridden, there are certain
1444 circumstances where the internal messages are used regardless of the
1445 setting of <code class="directive"><a href="#errordocument">ErrorDocument</a></code>. In
1446 particular, if a malformed request is detected, normal request processing
1447 will be immediately halted and the internal error message returned.
1448 This is necessary to guard against security problems caused by
1451 <p>If you are using mod_proxy, you may wish to enable
1452 <code class="directive"><a href="../mod/mod_proxy.html#proxyerroroverride">ProxyErrorOverride</a></code> so that you can provide
1453 custom error messages on behalf of your Origin servers. If you don't enable ProxyErrorOverride,
1454 Apache httpd will not generate custom error documents for proxied content.</p>
1458 <li><a href="../custom-error.html">documentation of
1459 customizable responses</a></li>
1462 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1463 <div class="directive-section"><h2><a name="ErrorLog" id="ErrorLog">ErrorLog</a> <a name="errorlog" id="errorlog">Directive</a></h2>
1464 <table class="directive">
1465 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Location where the server will log errors</td></tr>
1466 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code> ErrorLog <var>file-path</var>|syslog[:<var>facility</var>]</code></td></tr>
1467 <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>
1468 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1469 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1470 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1472 <p>The <code class="directive">ErrorLog</code> directive sets the name of
1473 the file to which the server will log any errors it encounters. If
1474 the <var>file-path</var> is not absolute then it is assumed to be
1475 relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1477 <pre class="prettyprint lang-config">ErrorLog "/var/log/httpd/error_log"</pre>
1480 <p>If the <var>file-path</var>
1481 begins with a pipe character "<code>|</code>" then it is assumed to be a
1482 command to spawn to handle the error log.</p>
1484 <pre class="prettyprint lang-config">ErrorLog "|/usr/local/bin/httpd_errors"</pre>
1487 <p>See the notes on <a href="../logs.html#piped">piped logs</a> for
1488 more information.</p>
1490 <p>Using <code>syslog</code> instead of a filename enables logging
1491 via syslogd(8) if the system supports it and if <code class="module"><a href="../mod/mod_syslog.html">mod_syslog</a></code>
1492 is loaded. The default is to use syslog facility <code>local7</code>,
1493 but you can override this by using the <code>syslog:<var>facility</var></code>
1494 syntax where <var>facility</var> can be one of the names usually documented in
1495 syslog(1). The facility is effectively global, and if it is changed
1496 in individual virtual hosts, the final facility specified affects the
1499 <pre class="prettyprint lang-config">ErrorLog syslog:user</pre>
1502 <p>Additional modules can provide their own ErrorLog providers. The syntax
1503 is similar to the <code>syslog</code> example above.</p>
1505 <p>SECURITY: See the <a href="../misc/security_tips.html#serverroot">security tips</a>
1506 document for details on why your security could be compromised
1507 if the directory where log files are stored is writable by
1508 anyone other than the user that starts the server.</p>
1509 <div class="warning"><h3>Note</h3>
1510 <p>When entering a file path on non-Unix platforms, care should be taken
1511 to make sure that only forward slashes are used even though the platform
1512 may allow the use of back slashes. In general it is a good idea to always
1513 use forward slashes throughout the configuration files.</p>
1518 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1519 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1522 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1523 <div class="directive-section"><h2><a name="ErrorLogFormat" id="ErrorLogFormat">ErrorLogFormat</a> <a name="errorlogformat" id="errorlogformat">Directive</a></h2>
1524 <table class="directive">
1525 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Format specification for error log entries</td></tr>
1526 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code> ErrorLogFormat [connection|request] <var>format</var></code></td></tr>
1527 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1528 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1529 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1531 <p><code class="directive">ErrorLogFormat</code> allows to specify what
1532 supplementary information is logged in the error log in addition to the
1533 actual log message.</p>
1535 <pre class="prettyprint lang-config">#Simple example
1536 ErrorLogFormat "[%t] [%l] [pid %P] %F: %E: [client %a] %M"</pre>
1539 <p>Specifying <code>connection</code> or <code>request</code> as first
1540 parameter allows to specify additional formats, causing additional
1541 information to be logged when the first message is logged for a specific
1542 connection or request, respectively. This additional information is only
1543 logged once per connection/request. If a connection or request is processed
1544 without causing any log message, the additional information is not logged
1547 <p>It can happen that some format string items do not produce output. For
1548 example, the Referer header is only present if the log message is
1549 associated to a request and the log message happens at a time when the
1550 Referer header has already been read from the client. If no output is
1551 produced, the default behavior is to delete everything from the preceding
1552 space character to the next space character. This means the log line is
1553 implicitly divided into fields on non-whitespace to whitespace transitions.
1554 If a format string item does not produce output, the whole field is
1555 omitted. For example, if the remote address <code>%a</code> in the log
1556 format <code>[%t] [%l] [%a] %M </code> is not available, the surrounding
1557 brackets are not logged either. Space characters can be escaped with a
1558 backslash to prevent them from delimiting a field. The combination '% '
1559 (percent space) is a zero-width field delimiter that does not produce any
1562 <p>The above behavior can be changed by adding modifiers to the format
1563 string item. A <code>-</code> (minus) modifier causes a minus to be logged if the
1564 respective item does not produce any output. In once-per-connection/request
1565 formats, it is also possible to use the <code>+</code> (plus) modifier. If an
1566 item with the plus modifier does not produce any output, the whole line is
1569 <p>A number as modifier can be used to assign a log severity level to a
1570 format item. The item will only be logged if the severity of the log
1571 message is not higher than the specified log severity level. The number can
1572 range from 1 (alert) over 4 (warn) and 7 (debug) to 15 (trace8).</p>
1574 <p>For example, here's what would happen if you added modifiers to
1575 the <code>%{Referer}i</code> token, which logs the
1576 <code>Referer</code> request header.</p>
1578 <table class="bordered"><tr class="header"><th>Modified Token</th><th>Meaning</th></tr>
1580 <td><code>%-{Referer}i</code></td>
1581 <td>Logs a <code>-</code> if <code>Referer</code> is not set.</td>
1584 <td><code>%+{Referer}i</code></td>
1585 <td>Omits the entire line if <code>Referer</code> is not set.</td>
1588 <td><code>%4{Referer}i</code></td>
1589 <td>Logs the <code>Referer</code> only if the log message severity
1590 is higher than 4.</td>
1594 <p>Some format string items accept additional parameters in braces.</p>
1596 <table class="bordered"><tr class="header"><th>Format String</th> <th>Description</th></tr>
1597 <tr><td><code>%%</code></td>
1598 <td>The percent sign</td></tr>
1599 <tr class="odd"><td><code>%a</code></td>
1600 <td>Client IP address and port of the request</td></tr>
1601 <tr><td><code>%{c}a</code></td>
1602 <td>Underlying peer IP address and port of the connection (see the
1603 <code class="module"><a href="../mod/mod_remoteip.html">mod_remoteip</a></code> module)</td></tr>
1604 <tr class="odd"><td><code>%A</code></td>
1605 <td>Local IP-address and port</td></tr>
1606 <tr><td><code>%{<em>name</em>}e</code></td>
1607 <td>Request environment variable <em>name</em></td></tr>
1608 <tr class="odd"><td><code>%E</code></td>
1609 <td>APR/OS error status code and string</td></tr>
1610 <tr><td><code>%F</code></td>
1611 <td>Source file name and line number of the log call</td></tr>
1612 <tr class="odd"><td><code>%{<em>name</em>}i</code></td>
1613 <td>Request header <em>name</em></td></tr>
1614 <tr><td><code>%k</code></td>
1615 <td>Number of keep-alive requests on this connection</td></tr>
1616 <tr class="odd"><td><code>%l</code></td>
1617 <td>Loglevel of the message</td></tr>
1618 <tr><td><code>%L</code></td>
1619 <td>Log ID of the request</td></tr>
1620 <tr class="odd"><td><code>%{c}L</code></td>
1621 <td>Log ID of the connection</td></tr>
1622 <tr><td><code>%{C}L</code></td>
1623 <td>Log ID of the connection if used in connection scope, empty otherwise</td></tr>
1624 <tr class="odd"><td><code>%m</code></td>
1625 <td>Name of the module logging the message</td></tr>
1626 <tr><td><code>%M</code></td>
1627 <td>The actual log message</td></tr>
1628 <tr class="odd"><td><code>%{<em>name</em>}n</code></td>
1629 <td>Request note <em>name</em></td></tr>
1630 <tr><td><code>%P</code></td>
1631 <td>Process ID of current process</td></tr>
1632 <tr class="odd"><td><code>%T</code></td>
1633 <td>Thread ID of current thread</td></tr>
1634 <tr><td><code>%{g}T</code></td>
1635 <td>System unique thread ID of current thread (the same ID as
1636 displayed by e.g. <code>top</code>; currently Linux only)</td></tr>
1637 <tr class="odd"><td><code>%t</code></td>
1638 <td>The current time</td></tr>
1639 <tr><td><code>%{u}t</code></td>
1640 <td>The current time including micro-seconds</td></tr>
1641 <tr class="odd"><td><code>%{cu}t</code></td>
1642 <td>The current time in compact ISO 8601 format, including
1643 micro-seconds</td></tr>
1644 <tr><td><code>%v</code></td>
1645 <td>The canonical <code class="directive"><a href="#servername">ServerName</a></code>
1646 of the current server.</td></tr>
1647 <tr class="odd"><td><code>%V</code></td>
1648 <td>The server name of the server serving the request according to the
1649 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code>
1651 <tr><td><code>\ </code> (backslash space)</td>
1652 <td>Non-field delimiting space</td></tr>
1653 <tr class="odd"><td><code>% </code> (percent space)</td>
1654 <td>Field delimiter (no output)</td></tr>
1657 <p>The log ID format <code>%L</code> produces a unique id for a connection
1658 or request. This can be used to correlate which log lines belong to the
1659 same connection or request, which request happens on which connection.
1660 A <code>%L</code> format string is also available in
1661 <code class="module"><a href="../mod/mod_log_config.html">mod_log_config</a></code> to allow to correlate access log entries
1662 with error log lines. If <code class="module"><a href="../mod/mod_unique_id.html">mod_unique_id</a></code> is loaded, its
1663 unique id will be used as log ID for requests.</p>
1665 <pre class="prettyprint lang-config">#Example (default format for threaded MPMs)
1666 ErrorLogFormat "[%{u}t] [%-m:%l] [pid %P:tid %T] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"</pre>
1669 <p>This would result in error messages such as:</p>
1671 <div class="example"><p><code>
1672 [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
1675 <p>Notice that, as discussed above, some fields are omitted
1676 entirely because they are not defined.</p>
1678 <pre class="prettyprint lang-config">#Example (similar to the 2.2.x format)
1679 ErrorLogFormat "[%t] [%l] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"</pre>
1682 <pre class="prettyprint lang-config">#Advanced example with request/connection log IDs
1683 ErrorLogFormat "[%{uc}t] [%-m:%-l] [R:%L] [C:%{C}L] %7F: %E: %M"
1684 ErrorLogFormat request "[%{uc}t] [R:%L] Request %k on C:%{c}L pid:%P tid:%T"
1685 ErrorLogFormat request "[%{uc}t] [R:%L] UA:'%+{User-Agent}i'"
1686 ErrorLogFormat request "[%{uc}t] [R:%L] Referer:'%+{Referer}i'"
1687 ErrorLogFormat connection "[%{uc}t] [C:%{c}L] local\ %a remote\ %A"</pre>
1693 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
1694 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1695 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1698 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1699 <div class="directive-section"><h2><a name="ExtendedStatus" id="ExtendedStatus">ExtendedStatus</a> <a name="extendedstatus" id="extendedstatus">Directive</a></h2>
1700 <table class="directive">
1701 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Keep track of extended status information for each
1703 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ExtendedStatus On|Off</code></td></tr>
1704 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ExtendedStatus Off[*]</code></td></tr>
1705 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
1706 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1707 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1709 <p>This option tracks additional data per worker about the
1710 currently executing request and creates a utilization summary.
1711 You can see these variables during runtime by configuring
1712 <code class="module"><a href="../mod/mod_status.html">mod_status</a></code>. Note that other modules may
1713 rely on this scoreboard.</p>
1715 <p>This setting applies to the entire server and cannot be
1716 enabled or disabled on a virtualhost-by-virtualhost basis.
1717 The collection of extended status information can slow down
1718 the server. Also note that this setting cannot be changed
1719 during a graceful restart.</p>
1722 <p>Note that loading <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> will change
1723 the default behavior to ExtendedStatus On, while other
1724 third party modules may do the same. Such modules rely on
1725 collecting detailed information about the state of all workers.
1726 The default is changed by <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> beginning
1727 with version 2.3.6. The previous default was always Off.</p>
1732 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1733 <div class="directive-section"><h2><a name="FileETag" id="FileETag">FileETag</a> <a name="fileetag" id="fileetag">Directive</a></h2>
1734 <table class="directive">
1735 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>File attributes used to create the ETag
1736 HTTP response header for static files</td></tr>
1737 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>FileETag <var>component</var> ...</code></td></tr>
1738 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>FileETag MTime Size</code></td></tr>
1739 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1740 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1741 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1742 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1743 <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
1747 The <code class="directive">FileETag</code> directive configures the file
1748 attributes that are used to create the <code>ETag</code> (entity
1749 tag) response header field when the document is based on a static file.
1750 (The <code>ETag</code> value is used in cache management to save
1751 network bandwidth.) The
1752 <code class="directive">FileETag</code> directive allows you to choose
1753 which of these -- if any -- should be used. The recognized keywords are:
1757 <dt><strong>INode</strong></dt>
1758 <dd>The file's i-node number will be included in the calculation</dd>
1759 <dt><strong>MTime</strong></dt>
1760 <dd>The date and time the file was last modified will be included</dd>
1761 <dt><strong>Size</strong></dt>
1762 <dd>The number of bytes in the file will be included</dd>
1763 <dt><strong>All</strong></dt>
1764 <dd>All available fields will be used. This is equivalent to:
1765 <pre class="prettyprint lang-config">FileETag INode MTime Size</pre>
1767 <dt><strong>None</strong></dt>
1768 <dd>If a document is file-based, no <code>ETag</code> field will be
1769 included in the response</dd>
1772 <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
1773 keywords may be prefixed with either <code>+</code> or <code>-</code>,
1774 which allow changes to be made to the default setting inherited
1775 from a broader scope. Any keyword appearing without such a prefix
1776 immediately and completely cancels the inherited setting.</p>
1778 <p>If a directory's configuration includes
1779 <code>FileETag INode MTime Size</code>, and a
1780 subdirectory's includes <code>FileETag -INode</code>,
1781 the setting for that subdirectory (which will be inherited by
1782 any sub-subdirectories that don't override it) will be equivalent to
1783 <code>FileETag MTime Size</code>.</p>
1784 <div class="warning"><h3>Warning</h3>
1785 Do not change the default for directories or locations that have WebDAV
1786 enabled and use <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> as a storage provider.
1787 <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> uses <code>MTime Size</code>
1788 as a fixed format for <code>ETag</code> comparisons on conditional requests.
1789 These conditional requests will break if the <code>ETag</code> format is
1790 changed via <code class="directive">FileETag</code>.
1792 <div class="note"><h3>Server Side Includes</h3>
1793 An ETag is not generated for responses parsed by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
1794 since the response entity can change without a change of the INode, MTime, or Size
1795 of the static file with embedded SSI directives.
1800 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1801 <div class="directive-section"><h2><a name="Files" id="Files"><Files></a> <a name="files" id="files">Directive</a></h2>
1802 <table class="directive">
1803 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to matched
1805 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Files <var>filename</var>> ... </Files></code></td></tr>
1806 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1807 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1808 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1809 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1811 <p>The <code class="directive"><Files></code> directive
1812 limits the scope of the enclosed directives by filename. It is comparable
1813 to the <code class="directive"><a href="#directory"><Directory></a></code>
1814 and <code class="directive"><a href="#location"><Location></a></code>
1815 directives. It should be matched with a <code></Files></code>
1816 directive. The directives given within this section will be applied to
1817 any object with a basename (last component of filename) matching the
1818 specified filename. <code class="directive"><Files></code>
1819 sections are processed in the order they appear in the
1820 configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
1821 <code>.htaccess</code> files are read, but before <code class="directive"><a href="#location"><Location></a></code> sections. Note
1822 that <code class="directive"><Files></code> can be nested
1823 inside <code class="directive"><a href="#directory"><Directory></a></code> sections to restrict the
1824 portion of the filesystem they apply to.</p>
1826 <p>The <var>filename</var> argument should include a filename, or
1827 a wild-card string, where <code>?</code> matches any single character,
1828 and <code>*</code> matches any sequences of characters.</p>
1829 <pre class="prettyprint lang-config"><Files "cat.html">
1830 # Insert stuff that applies to cat.html here
1833 <Files "?at.*">
1834 # This would apply to cat.html, bat.html, hat.php and so on.
1835 </Files></pre>
1837 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
1838 can also be used, with the addition of the
1839 <code>~</code> character. For example:</p>
1841 <pre class="prettyprint lang-config"><Files ~ "\.(gif|jpe?g|png)$">
1843 </Files></pre>
1846 <p>would match most common Internet graphics formats. <code class="directive"><a href="#filesmatch"><FilesMatch></a></code> is preferred,
1849 <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
1850 <code>.htaccess</code> files. This allows users to control access to
1851 their own files, at a file-by-file level.</p>
1856 <li><a href="../sections.html">How <Directory>, <Location>
1857 and <Files> sections work</a> for an explanation of how these
1858 different sections are combined when a request is received</li>
1861 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1862 <div class="directive-section"><h2><a name="FilesMatch" id="FilesMatch"><FilesMatch></a> <a name="filesmatch" id="filesmatch">Directive</a></h2>
1863 <table class="directive">
1864 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to regular-expression matched
1866 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><FilesMatch <var>regex</var>> ... </FilesMatch></code></td></tr>
1867 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1868 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1869 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1870 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1872 <p>The <code class="directive"><FilesMatch></code> directive
1873 limits the scope of the enclosed directives by filename, just as the
1874 <code class="directive"><a href="#files"><Files></a></code> directive
1875 does. However, it accepts a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular
1876 expression</a>. For example:</p>
1878 <pre class="prettyprint lang-config"><FilesMatch ".+\.(gif|jpe?g|png)$">
1880 </FilesMatch></pre>
1883 <p>would match most common Internet graphics formats.</p>
1885 <div class="note">The <code>.+</code> at the start of the regex ensures that
1886 files named <code>.png</code>, or <code>.gif</code>, for example,
1887 are not matched.</div>
1889 <p>From 2.4.8 onwards, named groups and backreferences are captured and
1890 written to the environment with the corresponding name prefixed with
1891 "MATCH_" and in upper case. This allows elements of files to be referenced
1892 from within <a href="../expr.html">expressions</a> and modules like
1893 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
1894 (unnamed) backreferences are ignored. Use named groups instead.</p>
1896 <pre class="prettyprint lang-config"><FilesMatch "^(?<sitename>[^/]+)">
1897 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
1898 </FilesMatch></pre>
1903 <li><a href="../sections.html">How <Directory>, <Location>
1904 and <Files> sections work</a> for an explanation of how these
1905 different sections are combined when a request is received</li>
1908 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1909 <div class="directive-section"><h2><a name="ForceType" id="ForceType">ForceType</a> <a name="forcetype" id="forcetype">Directive</a></h2>
1910 <table class="directive">
1911 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be served with the specified
1912 media type in the HTTP Content-Type header field</td></tr>
1913 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ForceType <var>media-type</var>|None</code></td></tr>
1914 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
1915 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1916 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1917 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1919 <p>When placed into an <code>.htaccess</code> file or a
1920 <code class="directive"><a href="#directory"><Directory></a></code>, or
1921 <code class="directive"><a href="#location"><Location></a></code> or
1922 <code class="directive"><a href="#files"><Files></a></code>
1923 section, this directive forces all matching files to be served
1924 with the content type identification given by
1925 <var>media-type</var>. For example, if you had a directory full of
1926 GIF files, but did not want to label them all with <code>.gif</code>,
1927 you might want to use:</p>
1929 <pre class="prettyprint lang-config">ForceType image/gif</pre>
1932 <p>Note that this directive overrides other indirect media type
1933 associations defined in mime.types or via the
1934 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code>.</p>
1936 <p>You can also override more general
1937 <code class="directive">ForceType</code> settings
1938 by using the value of <code>None</code>:</p>
1940 <pre class="prettyprint lang-config"># force all files to be image/gif:
1941 <Location "/images">
1945 # but normal mime-type associations here:
1946 <Location "/images/mixed">
1948 </Location></pre>
1951 <p>This directive primarily overrides the content types generated for
1952 static files served out of the filesystem. For resources other than
1953 static files, where the generator of the response typically specifies
1954 a Content-Type, this directive has no effect.</p>
1957 <div class="note"><h3>Note</h3>
1958 <p>If no handler is explicitly set for a request, the specified content
1959 type will also be used as the handler name. </p>
1961 <p>When explicit directives such as
1962 <code class="directive"><a href="#sethandler">SetHandler</a></code> or
1963 <code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code> do not apply
1964 to the current request, the internal handler name normally set by those
1965 directives is instead set to the content type specified by this directive.
1968 This is a historical behavior that some third-party modules
1969 (such as mod_php) may look for a "synthetic" content type used only to
1970 signal the module to take responsibility for the matching request.
1973 <p>Configurations that rely on such "synthetic" types should be avoided.
1974 Additionally, configurations that restrict access to
1975 <code class="directive"><a href="#sethandler">SetHandler</a></code> or
1976 <code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code> should
1977 restrict access to this directive as well.</p>
1982 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1983 <div class="directive-section"><h2><a name="GprofDir" id="GprofDir">GprofDir</a> <a name="gprofdir" id="gprofdir">Directive</a></h2>
1984 <table class="directive">
1985 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory to write gmon.out profiling data to. </td></tr>
1986 <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>
1987 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1988 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1989 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1991 <p>When the server has been compiled with gprof profiling support,
1992 <code class="directive">GprofDir</code> causes <code>gmon.out</code> files to
1993 be written to the specified directory when the process exits. If the
1994 argument ends with a percent symbol ('%'), subdirectories are created
1995 for each process id.</p>
1997 <p>This directive currently only works with the <code class="module"><a href="../mod/prefork.html">prefork</a></code>
2001 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2002 <div class="directive-section"><h2><a name="HostnameLookups" id="HostnameLookups">HostnameLookups</a> <a name="hostnamelookups" id="hostnamelookups">Directive</a></h2>
2003 <table class="directive">
2004 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables DNS lookups on client IP addresses</td></tr>
2005 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>HostnameLookups On|Off|Double</code></td></tr>
2006 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>HostnameLookups Off</code></td></tr>
2007 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2008 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2009 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2011 <p>This directive enables DNS lookups so that host names can be
2012 logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
2013 The value <code>Double</code> refers to doing double-reverse
2014 DNS lookup. That is, after a reverse lookup is performed, a forward
2015 lookup is then performed on that result. At least one of the IP
2016 addresses in the forward lookup must match the original
2017 address. (In "tcpwrappers" terminology this is called
2018 <code>PARANOID</code>.)</p>
2020 <p>Regardless of the setting, when <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code> is
2021 used for controlling access by hostname, a double reverse lookup
2022 will be performed. This is necessary for security. Note that the
2023 result of this double-reverse isn't generally available unless you
2024 set <code>HostnameLookups Double</code>. For example, if only
2025 <code>HostnameLookups On</code> and a request is made to an object
2026 that is protected by hostname restrictions, regardless of whether
2027 the double-reverse fails or not, CGIs will still be passed the
2028 single-reverse result in <code>REMOTE_HOST</code>.</p>
2030 <p>The default is <code>Off</code> in order to save the network
2031 traffic for those sites that don't truly need the reverse
2032 lookups done. It is also better for the end users because they
2033 don't have to suffer the extra latency that a lookup entails.
2034 Heavily loaded sites should leave this directive
2035 <code>Off</code>, since DNS lookups can take considerable
2036 amounts of time. The utility <code class="program"><a href="../programs/logresolve.html">logresolve</a></code>, compiled by
2037 default to the <code>bin</code> subdirectory of your installation
2038 directory, can be used to look up host names from logged IP addresses
2041 <p>Finally, if you have <a href="mod_authz_host.html#reqhost">hostname-based Require
2042 directives</a>, a hostname lookup will be performed regardless of
2043 the setting of <code>HostnameLookups</code>.</p>
2046 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2047 <div class="directive-section"><h2><a name="HttpProtocolOptions" id="HttpProtocolOptions">HttpProtocolOptions</a> <a name="httpprotocoloptions" id="httpprotocoloptions">Directive</a></h2>
2048 <table class="directive">
2049 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Modify restrictions on HTTP Request Messages</td></tr>
2050 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>HttpProtocolOptions [Strict|Unsafe] [RegisteredMethods|LenientMethods]
2051 [Allow0.9|Require1.0]</code></td></tr>
2052 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>HttpProtocolOptions Strict LenientMethods Allow0.9</code></td></tr>
2053 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2054 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2055 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2056 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.2.32 or 2.4.24 and later</td></tr>
2058 <p>This directive changes the rules applied to the HTTP Request Line
2059 (<a href="https://tools.ietf.org/html/rfc7230#section-3.1.1">RFC 7230 §3.1.1</a>) and the HTTP Request Header Fields
2060 (<a href="https://tools.ietf.org/html/rfc7230#section-3.2">RFC 7230 §3.2</a>), which are now applied by default or using
2061 the <code>Strict</code> option. Due to legacy modules, applications or
2062 custom user-agents which must be deprecated the <code>Unsafe</code>
2063 option has been added to revert to the legacy behaviors. These rules
2064 are applied prior to request processing, so must be configured at the
2065 global or default (first) matching virtual host section, by IP/port
2066 interface (and not by name) to be honored.</p>
2068 <p>Prior to the introduction of this directive, the Apache HTTP Server
2069 request message parsers were tolerant of a number of forms of input
2070 which did not conform to the protocol.
2071 <a href="https://tools.ietf.org/html/rfc7230#section-9.4">RFC 7230 §9.4 Request Splitting</a> and
2072 <a href="https://tools.ietf.org/html/rfc7230#section-9.5">§9.5 Response Smuggling</a> call out only two of the potential
2073 risks of accepting non-conformant request messages, while
2074 <a href="https://tools.ietf.org/html/rfc7230#section-3.5">RFC 7230 §3.5</a> "Message Parsing Robustness" identify the
2075 risks of accepting obscure whitespace and request message formatting.
2076 As of the introduction of this directive, all grammar rules of the
2077 specification are enforced in the default <code>Strict</code> operating
2078 mode, and the strict whitespace suggested by section 3.5 is enforced
2079 and cannot be relaxed.</p>
2081 <p>Users are strongly cautioned against toggling the <code>Unsafe</code>
2082 mode of operation, particularly on outward-facing, publicly accessible
2083 server deployments. If an interface is required for faulty monitoring
2084 or other custom service consumers running on an intranet, users should
2085 toggle the Unsafe option only on a specific virtual host configured
2086 to service their internal private network.</p>
2088 <p>Reviewing the messages logged to the <code class="directive">ErrorLog</code>,
2089 configured with <code class="directive">LogLevel</code> <code>debug</code> level,
2090 can help identify such faulty requests along with their origin.
2091 Users should pay particular attention to the 400 responses in the access
2092 log for invalid requests which were unexpectedly rejected.</p>
2094 <p><a href="https://tools.ietf.org/html/rfc7231#section-4.1">RFC 7231 §4.1</a> "Request Methods" "Overview" requires that
2095 origin servers shall respond with an error when an unsupported method
2096 is encountered in the request line. This already happens when the
2097 <code>LenientMethods</code> option is used, but administrators may wish
2098 to toggle the <code>RegisteredMethods</code> option and register any
2099 non-standard methods using the <code class="directive">RegisterHttpMethod</code>
2100 directive, particularly if the <code>Unsafe</code> option has been toggled.
2101 The <code>RegisteredMethods</code> option should <strong>not</strong>
2102 be toggled for forward proxy hosts, as the methods supported by the
2103 origin servers are unknown to the proxy server.</p>
2105 <p><a href="https://tools.ietf.org/html/rfc2616#section-19.6">RFC 2616 §19.6</a> "Compatibility With Previous Versions" had
2106 encouraged HTTP servers to support legacy HTTP/0.9 requests. RFC 7230
2107 supersedes this with "The expectation to support HTTP/0.9 requests has
2108 been removed" and offers additional comments in
2109 <a href="https://tools.ietf.org/html/rfc7230#appendix-A">RFC 7230 Appendix A</a>. The <code>Require1.0</code> option allows
2110 the user to remove support of the default <code>Allow0.9</code> option's
2114 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2115 <div class="directive-section"><h2><a name="If" id="If"><If></a> <a name="if" id="if">Directive</a></h2>
2116 <table class="directive">
2117 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is
2118 satisfied by a request at runtime</td></tr>
2119 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><If <var>expression</var>> ... </If></code></td></tr>
2120 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2121 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2122 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2123 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2125 <p>The <code class="directive"><If></code> directive
2126 evaluates an expression at runtime, and applies the enclosed
2127 directives if and only if the expression evaluates to true.
2130 <pre class="prettyprint lang-config"><If "-z req('Host')"></pre>
2133 <p>would match HTTP/1.0 requests without a <var>Host:</var> header.
2134 Expressions may contain various shell-like operators for string
2135 comparison (<code>==</code>, <code>!=</code>, <code><</code>, ...),
2136 integer comparison (<code>-eq</code>, <code>-ne</code>, ...),
2137 and others (<code>-n</code>, <code>-z</code>, <code>-f</code>, ...).
2138 It is also possible to use regular expressions, </p>
2140 <pre class="prettyprint lang-config"><If "%{QUERY_STRING} =~ /(delete|commit)=.*?elem/"></pre>
2143 <p>shell-like pattern matches and many other operations. These operations
2144 can be done on request headers (<code>req</code>), environment variables
2145 (<code>env</code>), and a large number of other properties. The full
2146 documentation is available in <a href="../expr.html">Expressions in
2147 Apache HTTP Server</a>.</p>
2149 <p>Only directives that support the <a href="directive-dict.html#Context">directory context</a> can be used within this configuration section.</p>
2151 <div class="warning">
2152 Certain variables, such as <code>CONTENT_TYPE</code> and other
2153 response headers, are set after <If> conditions have already
2154 been evaluated, and so will not be available to use in this
2161 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
2162 for a complete reference and more examples.</li>
2163 <li><code class="directive"><a href="#elseif"><ElseIf></a></code></li>
2164 <li><code class="directive"><a href="#else"><Else></a></code></li>
2165 <li><a href="../sections.html">How <Directory>, <Location>,
2166 <Files> sections work</a> for an explanation of how these
2167 different sections are combined when a request is received.
2168 <code class="directive"><If></code>,
2169 <code class="directive"><ElseIf></code>, and
2170 <code class="directive"><Else></code> are applied last.</li>
2173 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2174 <div class="directive-section"><h2><a name="IfDefine" id="IfDefine"><IfDefine></a> <a name="ifdefine" id="ifdefine">Directive</a></h2>
2175 <table class="directive">
2176 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that will be processed only
2177 if a test is true at startup</td></tr>
2178 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfDefine [!]<var>parameter-name</var>> ...
2179 </IfDefine></code></td></tr>
2180 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2181 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2182 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2183 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2185 <p>The <code><IfDefine <var>test</var>>...</IfDefine>
2186 </code> section is used to mark directives that are conditional. The
2187 directives within an <code class="directive"><IfDefine></code>
2188 section are only processed if the <var>test</var> is true. If <var>
2189 test</var> is false, everything between the start and end markers is
2192 <p>The <var>test</var> in the <code class="directive"><IfDefine></code> section directive can be one of two forms:</p>
2195 <li><var>parameter-name</var></li>
2197 <li><code>!</code><var>parameter-name</var></li>
2200 <p>In the former case, the directives between the start and end
2201 markers are only processed if the parameter named
2202 <var>parameter-name</var> is defined. The second format reverses
2203 the test, and only processes the directives if
2204 <var>parameter-name</var> is <strong>not</strong> defined.</p>
2206 <p>The <var>parameter-name</var> argument is a define as given on the
2207 <code class="program"><a href="../programs/httpd.html">httpd</a></code> command line via <code>-D<var>parameter</var>
2208 </code> at the time the server was started or by the <code class="directive"><a href="#define">Define</a></code> directive.</p>
2210 <p><code class="directive"><IfDefine></code> sections are
2211 nest-able, which can be used to implement simple
2212 multiple-parameter tests. Example:</p>
2214 <div class="example"><p><code>httpd -DReverseProxy -DUseCache -DMemCache ...</code></p></div>
2215 <pre class="prettyprint lang-config"><IfDefine ReverseProxy>
2216 LoadModule proxy_module modules/mod_proxy.so
2217 LoadModule proxy_http_module modules/mod_proxy_http.so
2218 <IfDefine UseCache>
2219 LoadModule cache_module modules/mod_cache.so
2220 <IfDefine MemCache>
2221 LoadModule mem_cache_module modules/mod_mem_cache.so
2223 <IfDefine !MemCache>
2224 LoadModule cache_disk_module modules/mod_cache_disk.so
2227 </IfDefine></pre>
2231 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2232 <div class="directive-section"><h2><a name="IfFile" id="IfFile"><IfFile></a> <a name="iffile" id="iffile">Directive</a></h2>
2233 <table class="directive">
2234 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that will be processed only
2235 if file exists at startup</td></tr>
2236 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfFile [!]<var>parameter-name</var>> ...
2237 </IfFile></code></td></tr>
2238 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2239 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2240 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2242 <p>The <code><IfFile <var>filename</var>>...</IfFile>
2243 </code> section is used to mark directives that are conditional on
2244 the existence of a file on disk. The directives within an
2245 <code class="directive"><IfFile></code> section are only
2246 processed if the <var>filename</var> exists. If <var> filename</var>
2247 doesn't exist, everything between the start and end markers is
2248 ignored. <var>filename</var> can be an absolute path or a path
2249 relative to the server root.</p>
2251 <p>The <var>filename</var> in the <code class="directive"><IfFile
2252 ></code> section directive can take the same forms as the
2253 <var>test</var> variable in the <code class="directive"><IfDefine
2254 ></code> section, i.e. the test can be negated if the <code>
2255 !</code> character is placed directly before <var>filename</var>.
2258 <p>If a relative <var>filename</var> is supplied, the check is
2259 <code class="directive">ServerRoot</code> relative. In the case where
2260 this directive occurs before the <code class="directive">ServerRoot</code>,
2261 the path will be checked relative to the compiled-in server root or
2262 the server root passed in on the command line via the <code>-d</code>
2267 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2268 <div class="directive-section"><h2><a name="IfModule" id="IfModule"><IfModule></a> <a name="ifmodule" id="ifmodule">Directive</a></h2>
2269 <table class="directive">
2270 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that are processed conditional on the
2271 presence or absence of a specific module</td></tr>
2272 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfModule [!]<var>module-file</var>|<var>module-identifier</var>> ...
2273 </IfModule></code></td></tr>
2274 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2275 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2276 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2277 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2279 <p>The <code><IfModule <var>test</var>>...</IfModule></code>
2280 section is used to mark directives that are conditional on the presence of
2281 a specific module. The directives within an <code class="directive"><IfModule></code> section are only processed if the <var>test</var>
2282 is true. If <var>test</var> is false, everything between the start and
2283 end markers is ignored.</p>
2285 <p>The <var>test</var> in the <code class="directive"><IfModule></code> section directive can be one of two forms:</p>
2288 <li><var>module</var></li>
2290 <li>!<var>module</var></li>
2293 <p>In the former case, the directives between the start and end
2294 markers are only processed if the module named <var>module</var>
2295 is included in Apache httpd -- either compiled in or
2296 dynamically loaded using <code class="directive"><a href="../mod/mod_so.html#loadmodule">LoadModule</a></code>. The second format reverses the test,
2297 and only processes the directives if <var>module</var> is
2298 <strong>not</strong> included.</p>
2300 <p>The <var>module</var> argument can be either the module identifier or
2301 the file name of the module, at the time it was compiled. For example,
2302 <code>rewrite_module</code> is the identifier and
2303 <code>mod_rewrite.c</code> is the file name. If a module consists of
2304 several source files, use the name of the file containing the string
2305 <code>STANDARD20_MODULE_STUFF</code>.</p>
2307 <p><code class="directive"><IfModule></code> sections are
2308 nest-able, which can be used to implement simple multiple-module
2311 <div class="note">This section should only be used if you need to have one
2312 configuration file that works whether or not a specific module
2313 is available. In normal operation, directives need not be
2314 placed in <code class="directive"><IfModule></code>
2318 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2319 <div class="directive-section"><h2><a name="Include" id="Include">Include</a> <a name="include" id="include">Directive</a></h2>
2320 <table class="directive">
2321 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2322 the server configuration files</td></tr>
2323 <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>
2324 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2325 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2326 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2327 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Directory
2328 wildcard matching available in 2.3.6 and later</td></tr>
2330 <p>This directive allows inclusion of other configuration files
2331 from within the server configuration files.</p>
2333 <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used
2334 in the filename or directory parts of the path to include several files
2335 at once, in alphabetical order. In addition, if
2336 <code class="directive">Include</code> points to a directory, rather than a file,
2337 Apache httpd will read all files in that directory and any subdirectory.
2338 However, including entire directories is not recommended, because it is
2339 easy to accidentally leave temporary files in a directory that can cause
2340 <code class="program"><a href="../programs/httpd.html">httpd</a></code> to fail. Instead, we encourage you to use the
2341 wildcard syntax shown below, to include files that match a particular
2342 pattern, such as *.conf, for example.</p>
2344 <p>The <code class="directive"><a href="#include">Include</a></code> directive will
2345 <strong>fail with an error</strong> if a wildcard expression does not
2346 match any file. The <code class="directive"><a href="#includeoptional">IncludeOptional</a></code>
2347 directive can be used if non-matching wildcards should be ignored.</p>
2349 <p>The file path specified may be an absolute path, or may be relative
2350 to the <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory.</p>
2354 <pre class="prettyprint lang-config">Include /usr/local/apache2/conf/ssl.conf
2355 Include /usr/local/apache2/conf/vhosts/*.conf</pre>
2358 <p>Or, providing paths relative to your <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory:</p>
2360 <pre class="prettyprint lang-config">Include conf/ssl.conf
2361 Include conf/vhosts/*.conf</pre>
2364 <p>Wildcards may be included in the directory or file portion of the
2365 path. This example will fail if there is no subdirectory in conf/vhosts
2366 that contains at least one *.conf file:</p>
2368 <pre class="prettyprint lang-config">Include conf/vhosts/*/*.conf</pre>
2371 <p>Alternatively, the following command will just be ignored in case of
2372 missing files or directories:</p>
2374 <pre class="prettyprint lang-config">IncludeOptional conf/vhosts/*/*.conf</pre>
2380 <li><code class="directive"><a href="#includeoptional">IncludeOptional</a></code></li>
2381 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2384 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2385 <div class="directive-section"><h2><a name="IncludeOptional" id="IncludeOptional">IncludeOptional</a> <a name="includeoptional" id="includeoptional">Directive</a></h2>
2386 <table class="directive">
2387 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2388 the server configuration files</td></tr>
2389 <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>
2390 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2391 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2392 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2393 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in 2.3.6 and later</td></tr>
2395 <p>This directive allows inclusion of other configuration files
2396 from within the server configuration files. It works identically to the
2397 <code class="directive"><a href="#include">Include</a></code> directive, with the
2398 exception that if wildcards do not match any file or directory, the
2399 <code class="directive"><a href="#includeoptional">IncludeOptional</a></code> directive will be
2400 silently ignored instead of causing an error.</p>
2404 <li><code class="directive"><a href="#include">Include</a></code></li>
2405 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2408 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2409 <div class="directive-section"><h2><a name="KeepAlive" id="KeepAlive">KeepAlive</a> <a name="keepalive" id="keepalive">Directive</a></h2>
2410 <table class="directive">
2411 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables HTTP persistent connections</td></tr>
2412 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAlive On|Off</code></td></tr>
2413 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAlive On</code></td></tr>
2414 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2415 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2416 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2418 <p>The Keep-Alive extension to HTTP/1.0 and the persistent
2419 connection feature of HTTP/1.1 provide long-lived HTTP sessions
2420 which allow multiple requests to be sent over the same TCP
2421 connection. In some cases this has been shown to result in an
2422 almost 50% speedup in latency times for HTML documents with
2423 many images. To enable Keep-Alive connections, set
2424 <code>KeepAlive On</code>.</p>
2426 <p>For HTTP/1.0 clients, Keep-Alive connections will only be
2427 used if they are specifically requested by a client. In
2428 addition, a Keep-Alive connection with an HTTP/1.0 client can
2429 only be used when the length of the content is known in
2430 advance. This implies that dynamic content such as CGI output,
2431 SSI pages, and server-generated directory listings will
2432 generally not use Keep-Alive connections to HTTP/1.0 clients.
2433 For HTTP/1.1 clients, persistent connections are the default
2434 unless otherwise specified. If the client requests it, chunked
2435 encoding will be used in order to send content of unknown
2436 length over persistent connections.</p>
2438 <p>When a client uses a Keep-Alive connection, it will be counted
2439 as a single "request" for the <code class="directive"><a href="../mod/mpm_common.html#maxconnectionsperchild">MaxConnectionsPerChild</a></code> directive, regardless
2440 of how many requests are sent using the connection.</p>
2444 <li><code class="directive"><a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></code></li>
2447 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2448 <div class="directive-section"><h2><a name="KeepAliveTimeout" id="KeepAliveTimeout">KeepAliveTimeout</a> <a name="keepalivetimeout" id="keepalivetimeout">Directive</a></h2>
2449 <table class="directive">
2450 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for subsequent
2451 requests on a persistent connection</td></tr>
2452 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAliveTimeout <var>num</var>[ms]</code></td></tr>
2453 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAliveTimeout 5</code></td></tr>
2454 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2455 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2456 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2458 <p>The number of seconds Apache httpd will wait for a subsequent
2459 request before closing the connection. By adding a postfix of ms the
2460 timeout can be also set in milliseconds. Once a request has been
2461 received, the timeout value specified by the
2462 <code class="directive"><a href="#timeout">Timeout</a></code> directive applies.</p>
2464 <p>Setting <code class="directive">KeepAliveTimeout</code> to a high value
2465 may cause performance problems in heavily loaded servers. The
2466 higher the timeout, the more server processes will be kept
2467 occupied waiting on connections with idle clients.</p>
2469 <p>If <code class="directive">KeepAliveTimeout</code> is <strong>not</strong>
2470 set for a name-based virtual host, the value of the first defined
2471 virtual host best matching the local IP and port will be used.</p>
2474 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2475 <div class="directive-section"><h2><a name="Limit" id="Limit"><Limit></a> <a name="limit" id="limit">Directive</a></h2>
2476 <table class="directive">
2477 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict enclosed access controls to only certain HTTP
2479 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Limit <var>method</var> [<var>method</var>] ... > ...
2480 </Limit></code></td></tr>
2481 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2482 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2483 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2484 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2486 <p>Access controls are normally effective for
2487 <strong>all</strong> access methods, and this is the usual
2488 desired behavior. <strong>In the general case, access control
2489 directives should not be placed within a
2490 <code class="directive"><Limit></code> section.</strong></p>
2492 <p>The purpose of the <code class="directive"><Limit></code>
2493 directive is to restrict the effect of the access controls to the
2494 nominated HTTP methods. For all other methods, the access
2495 restrictions that are enclosed in the <code class="directive"><Limit></code> bracket <strong>will have no
2496 effect</strong>. The following example applies the access control
2497 only to the methods <code>POST</code>, <code>PUT</code>, and
2498 <code>DELETE</code>, leaving all other methods unprotected:</p>
2500 <pre class="prettyprint lang-config"><Limit POST PUT DELETE>
2502 </Limit></pre>
2505 <p>The method names listed can be one or more of: <code>GET</code>,
2506 <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
2507 <code>CONNECT</code>, <code>OPTIONS</code>,
2508 <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
2509 <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
2510 <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
2511 case-sensitive.</strong> If <code>GET</code> is used, it will also
2512 restrict <code>HEAD</code> requests. The <code>TRACE</code> method
2513 cannot be limited (see <code class="directive"><a href="#traceenable">TraceEnable</a></code>).</p>
2515 <div class="warning">A <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section should always be
2516 used in preference to a <code class="directive"><Limit></code>
2517 section when restricting access, since a <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section provides protection
2518 against arbitrary methods.</div>
2520 <p>The <code class="directive"><Limit></code> and
2521 <code class="directive"><a href="#limitexcept"><LimitExcept></a></code>
2522 directives may be nested. In this case, each successive level of
2523 <code class="directive"><Limit></code> or <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> directives must
2524 further restrict the set of methods to which access controls apply.</p>
2526 <div class="warning">When using
2527 <code class="directive"><Limit></code> or
2528 <code class="directive"><LimitExcept></code> directives with
2529 the <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directive,
2530 note that the first <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code>
2531 to succeed authorizes the request, regardless of the presence of other
2532 <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directives.</div>
2534 <p>For example, given the following configuration, all users will
2535 be authorized for <code>POST</code> requests, and the
2536 <code>Require group editors</code> directive will be ignored
2539 <pre class="prettyprint lang-config"><LimitExcept GET>
2541 </LimitExcept>
2543 Require group editors
2544 </Limit></pre>
2548 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2549 <div class="directive-section"><h2><a name="LimitExcept" id="LimitExcept"><LimitExcept></a> <a name="limitexcept" id="limitexcept">Directive</a></h2>
2550 <table class="directive">
2551 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict access controls to all HTTP methods
2552 except the named ones</td></tr>
2553 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LimitExcept <var>method</var> [<var>method</var>] ... > ...
2554 </LimitExcept></code></td></tr>
2555 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2556 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2557 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2558 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2560 <p><code class="directive"><LimitExcept></code> and
2561 <code></LimitExcept></code> are used to enclose
2562 a group of access control directives which will then apply to any
2563 HTTP access method <strong>not</strong> listed in the arguments;
2564 i.e., it is the opposite of a <code class="directive"><a href="#limit"><Limit></a></code> section and can be used to control
2565 both standard and nonstandard/unrecognized methods. See the
2566 documentation for <code class="directive"><a href="#limit"><Limit></a></code> for more details.</p>
2570 <pre class="prettyprint lang-config"><LimitExcept POST GET>
2572 </LimitExcept></pre>
2577 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2578 <div class="directive-section"><h2><a name="LimitInternalRecursion" id="LimitInternalRecursion">LimitInternalRecursion</a> <a name="limitinternalrecursion" id="limitinternalrecursion">Directive</a></h2>
2579 <table class="directive">
2580 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine maximum number of internal redirects and nested
2581 subrequests</td></tr>
2582 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitInternalRecursion <var>number</var> [<var>number</var>]</code></td></tr>
2583 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitInternalRecursion 10</code></td></tr>
2584 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2585 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2586 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2588 <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
2589 redirects the original request to a CGI script. A subrequest is Apache httpd's
2590 mechanism to find out what would happen for some URI if it were requested.
2591 For example, <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> uses subrequests to look for the
2592 files listed in the <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
2595 <p><code class="directive">LimitInternalRecursion</code> prevents the server
2596 from crashing when entering an infinite loop of internal redirects or
2597 subrequests. Such loops are usually caused by misconfigurations.</p>
2599 <p>The directive stores two different limits, which are evaluated on
2600 per-request basis. The first <var>number</var> is the maximum number of
2601 internal redirects that may follow each other. The second <var>number</var>
2602 determines how deeply subrequests may be nested. If you specify only one
2603 <var>number</var>, it will be assigned to both limits.</p>
2605 <pre class="prettyprint lang-config">LimitInternalRecursion 5</pre>
2609 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2610 <div class="directive-section"><h2><a name="LimitRequestBody" id="LimitRequestBody">LimitRequestBody</a> <a name="limitrequestbody" id="limitrequestbody">Directive</a></h2>
2611 <table class="directive">
2612 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restricts the total size of the HTTP request body sent
2613 from the client</td></tr>
2614 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestBody <var>bytes</var></code></td></tr>
2615 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestBody 0</code></td></tr>
2616 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2617 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2618 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2619 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2621 <p>This directive specifies the number of <var>bytes</var> from 0
2622 (meaning unlimited) to 2147483647 (2GB) that are allowed in a
2623 request body. See the note below for the limited applicability
2624 to proxy requests.</p>
2626 <p>The <code class="directive">LimitRequestBody</code> directive allows
2627 the user to set a limit on the allowed size of an HTTP request
2628 message body within the context in which the directive is given
2629 (server, per-directory, per-file or per-location). If the client
2630 request exceeds that limit, the server will return an error
2631 response instead of servicing the request. The size of a normal
2632 request message body will vary greatly depending on the nature of
2633 the resource and the methods allowed on that resource. CGI scripts
2634 typically use the message body for retrieving form information.
2635 Implementations of the <code>PUT</code> method will require
2636 a value at least as large as any representation that the server
2637 wishes to accept for that resource.</p>
2639 <p>This directive gives the server administrator greater
2640 control over abnormal client request behavior, which may be
2641 useful for avoiding some forms of denial-of-service
2644 <p>If, for example, you are permitting file upload to a particular
2645 location and wish to limit the size of the uploaded file to 100K,
2646 you might use the following directive:</p>
2648 <pre class="prettyprint lang-config">LimitRequestBody 102400</pre>
2651 <div class="note"><p>For a full description of how this directive is interpreted by
2652 proxy requests, see the <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> documentation.</p>
2657 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2658 <div class="directive-section"><h2><a name="LimitRequestFields" id="LimitRequestFields">LimitRequestFields</a> <a name="limitrequestfields" id="limitrequestfields">Directive</a></h2>
2659 <table class="directive">
2660 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of HTTP request header fields that
2661 will be accepted from the client</td></tr>
2662 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFields <var>number</var></code></td></tr>
2663 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFields 100</code></td></tr>
2664 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2665 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2666 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2668 <p><var>Number</var> is an integer from 0 (meaning unlimited) to
2669 32767. The default value is defined by the compile-time
2670 constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
2673 <p>The <code class="directive">LimitRequestFields</code> directive allows
2674 the server administrator to modify the limit on the number of
2675 request header fields allowed in an HTTP request. A server needs
2676 this value to be larger than the number of fields that a normal
2677 client request might include. The number of request header fields
2678 used by a client rarely exceeds 20, but this may vary among
2679 different client implementations, often depending upon the extent
2680 to which a user has configured their browser to support detailed
2681 content negotiation. Optional HTTP extensions are often expressed
2682 using request header fields.</p>
2684 <p>This directive gives the server administrator greater
2685 control over abnormal client request behavior, which may be
2686 useful for avoiding some forms of denial-of-service attacks.
2687 The value should be increased if normal clients see an error
2688 response from the server that indicates too many fields were
2689 sent in the request.</p>
2693 <pre class="prettyprint lang-config">LimitRequestFields 50</pre>
2696 <div class="warning"><h3>Warning</h3>
2697 <p> When name-based virtual hosting is used, the value for this
2698 directive is taken from the default (first-listed) virtual host for the
2699 local IP and port combination.</p>
2704 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2705 <div class="directive-section"><h2><a name="LimitRequestFieldSize" id="LimitRequestFieldSize">LimitRequestFieldSize</a> <a name="limitrequestfieldsize" id="limitrequestfieldsize">Directive</a></h2>
2706 <table class="directive">
2707 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of the HTTP request header allowed from the
2709 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFieldSize <var>bytes</var></code></td></tr>
2710 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFieldSize 8190</code></td></tr>
2711 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2712 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2713 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2715 <p>This directive specifies the number of <var>bytes</var>
2716 that will be allowed in an HTTP request header.</p>
2718 <p>The <code class="directive">LimitRequestFieldSize</code> directive
2719 allows the server administrator to set the limit
2720 on the allowed size of an HTTP request header field. A server
2721 needs this value to be large enough to hold any one header field
2722 from a normal client request. The size of a normal request header
2723 field will vary greatly among different client implementations,
2724 often depending upon the extent to which a user has configured
2725 their browser to support detailed content negotiation. SPNEGO
2726 authentication headers can be up to 12392 bytes.</p>
2728 <p>This directive gives the server administrator greater
2729 control over abnormal client request behavior, which may be
2730 useful for avoiding some forms of denial-of-service attacks.</p>
2734 <pre class="prettyprint lang-config">LimitRequestFieldSize 4094</pre>
2737 <div class="note">Under normal conditions, the value should not be changed from
2740 <div class="warning"><h3>Warning</h3>
2741 <p> When name-based virtual hosting is used, the value for this
2742 directive is taken from the default (first-listed) virtual host best
2743 matching the current IP address and port combination.</p>
2747 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2748 <div class="directive-section"><h2><a name="LimitRequestLine" id="LimitRequestLine">LimitRequestLine</a> <a name="limitrequestline" id="limitrequestline">Directive</a></h2>
2749 <table class="directive">
2750 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limit the size of the HTTP request line that will be accepted
2751 from the client</td></tr>
2752 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestLine <var>bytes</var></code></td></tr>
2753 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestLine 8190</code></td></tr>
2754 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2755 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2756 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2758 <p>This directive sets the number of <var>bytes</var> that will be
2759 allowed on the HTTP request-line.</p>
2761 <p>The <code class="directive">LimitRequestLine</code> directive allows
2762 the server administrator to set the limit on the allowed size
2763 of a client's HTTP request-line. Since the request-line consists of the
2764 HTTP method, URI, and protocol version, the
2765 <code class="directive">LimitRequestLine</code> directive places a
2766 restriction on the length of a request-URI allowed for a request
2767 on the server. A server needs this value to be large enough to
2768 hold any of its resource names, including any information that
2769 might be passed in the query part of a <code>GET</code> request.</p>
2771 <p>This directive gives the server administrator greater
2772 control over abnormal client request behavior, which may be
2773 useful for avoiding some forms of denial-of-service attacks.</p>
2777 <pre class="prettyprint lang-config">LimitRequestLine 4094</pre>
2780 <div class="note">Under normal conditions, the value should not be changed from
2783 <div class="warning"><h3>Warning</h3>
2784 <p> When name-based virtual hosting is used, the value for this
2785 directive is taken from the default (first-listed) virtual host best
2786 matching the current IP address and port combination.</p>
2791 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2792 <div class="directive-section"><h2><a name="LimitXMLRequestBody" id="LimitXMLRequestBody">LimitXMLRequestBody</a> <a name="limitxmlrequestbody" id="limitxmlrequestbody">Directive</a></h2>
2793 <table class="directive">
2794 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of an XML-based request body</td></tr>
2795 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitXMLRequestBody <var>bytes</var></code></td></tr>
2796 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitXMLRequestBody 1000000</code></td></tr>
2797 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2798 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2799 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2800 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2802 <p>Limit (in bytes) on maximum size of an XML-based request
2803 body. A value of <code>0</code> will disable any checking.</p>
2807 <pre class="prettyprint lang-config">LimitXMLRequestBody 0</pre>
2812 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2813 <div class="directive-section"><h2><a name="Location" id="Location"><Location></a> <a name="location" id="location">Directive</a></h2>
2814 <table class="directive">
2815 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to matching
2817 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Location
2818 <var>URL-path</var>|<var>URL</var>> ... </Location></code></td></tr>
2819 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2820 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2821 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2823 <p>The <code class="directive"><Location></code> directive
2824 limits the scope of the enclosed directives by URL. It is similar to the
2825 <code class="directive"><a href="#directory"><Directory></a></code>
2826 directive, and starts a subsection which is terminated with a
2827 <code></Location></code> directive. <code class="directive"><Location></code> sections are processed in the
2828 order they appear in the configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
2829 <code>.htaccess</code> files are read, and after the <code class="directive"><a href="#files"><Files></a></code> sections.</p>
2831 <p><code class="directive"><Location></code> sections operate
2832 completely outside the filesystem. This has several consequences.
2833 Most importantly, <code class="directive"><Location></code>
2834 directives should not be used to control access to filesystem
2835 locations. Since several different URLs may map to the same
2836 filesystem location, such access controls may by circumvented.</p>
2838 <p>The enclosed directives will be applied to the request if the path component
2839 of the URL meets <em>any</em> of the following criteria:
2842 <li>The specified location matches exactly the path component of the URL.
2844 <li>The specified location, which ends in a forward slash, is a prefix
2845 of the path component of the URL (treated as a context root).
2847 <li>The specified location, with the addition of a trailing slash, is a
2848 prefix of the path component of the URL (also treated as a context root).
2852 In the example below, where no trailing slash is used, requests to
2853 /private1, /private1/ and /private1/file.txt will have the enclosed
2854 directives applied, but /private1other would not.
2856 <pre class="prettyprint lang-config"><Location "/private1">
2858 </Location></pre>
2861 In the example below, where a trailing slash is used, requests to
2862 /private2/ and /private2/file.txt will have the enclosed
2863 directives applied, but /private2 and /private2other would not.
2865 <pre class="prettyprint lang-config"><Location "/private2<em>/</em>">
2867 </Location></pre>
2870 <div class="note"><h3>When to use <code class="directive"><Location></code></h3>
2872 <p>Use <code class="directive"><Location></code> to apply
2873 directives to content that lives outside the filesystem. For
2874 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
2875 <code><Location "/"></code>, which is an easy way to
2876 apply a configuration to the entire server.</p>
2879 <p>For all origin (non-proxy) requests, the URL to be matched is a
2880 URL-path of the form <code>/path/</code>. <em>No scheme, hostname,
2881 port, or query string may be included.</em> For proxy requests, the
2882 URL to be matched is of the form
2883 <code>scheme://servername/path</code>, and you must include the
2886 <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
2887 any single character, and <code>*</code> matches any sequences of
2888 characters. Neither wildcard character matches a / in the URL-path.</p>
2890 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
2891 can also be used, with the addition of the <code>~</code>
2892 character. For example:</p>
2894 <pre class="prettyprint lang-config"><Location ~ "/(extra|special)/data">
2896 </Location></pre>
2899 <p>would match URLs that contained the substring <code>/extra/data</code>
2900 or <code>/special/data</code>. The directive <code class="directive"><a href="#locationmatch"><LocationMatch></a></code> behaves
2901 identical to the regex version of <code class="directive"><Location></code>, and is preferred, for the
2902 simple reason that <code>~</code> is hard to distinguish from
2903 <code>-</code> in many fonts.</p>
2905 <p>The <code class="directive"><Location></code>
2906 functionality is especially useful when combined with the
2907 <code class="directive"><a href="#sethandler">SetHandler</a></code>
2908 directive. For example, to enable status requests but allow them
2909 only from browsers at <code>example.com</code>, you might use:</p>
2911 <pre class="prettyprint lang-config"><Location "/status">
2912 SetHandler server-status
2913 Require host example.com
2914 </Location></pre>
2917 <div class="note"><h3>Note about / (slash)</h3>
2918 <p>The slash character has special meaning depending on where in a
2919 URL it appears. People may be used to its behavior in the filesystem
2920 where multiple adjacent slashes are frequently collapsed to a single
2921 slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
2922 <code>/home/foo</code>). In URL-space this is not necessarily true.
2923 The <code class="directive"><a href="#locationmatch"><LocationMatch></a></code>
2924 directive and the regex version of <code class="directive"><Location></code> require you to explicitly specify multiple
2925 slashes if that is your intention.</p>
2927 <p>For example, <code><LocationMatch "^/abc"></code> would match
2928 the request URL <code>/abc</code> but not the request URL <code>
2929 //abc</code>. The (non-regex) <code class="directive"><Location></code> directive behaves similarly when used for
2930 proxy requests. But when (non-regex) <code class="directive"><Location></code> is used for non-proxy requests it will
2931 implicitly match multiple slashes with a single slash. For example,
2932 if you specify <code><Location "/abc/def"></code> and the
2933 request is to <code>/abc//def</code> then it will match.</p>
2938 <li><a href="../sections.html">How <Directory>, <Location>
2939 and <Files> sections work</a> for an explanation of how these
2940 different sections are combined when a request is received.</li>
2941 <li><code class="directive"><a href="#locationmatch">LocationMatch</a></code></li>
2944 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2945 <div class="directive-section"><h2><a name="LocationMatch" id="LocationMatch"><LocationMatch></a> <a name="locationmatch" id="locationmatch">Directive</a></h2>
2946 <table class="directive">
2947 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to regular-expression
2948 matching URLs</td></tr>
2949 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LocationMatch
2950 <var>regex</var>> ... </LocationMatch></code></td></tr>
2951 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2952 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2953 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2955 <p>The <code class="directive"><LocationMatch></code> directive
2956 limits the scope of the enclosed directives by URL, in an identical manner
2957 to <code class="directive"><a href="#location"><Location></a></code>. However,
2958 it takes a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
2959 as an argument instead of a simple string. For example:</p>
2961 <pre class="prettyprint lang-config"><LocationMatch "/(extra|special)/data">
2963 </LocationMatch></pre>
2966 <p>would match URLs that contained the substring <code>/extra/data</code>
2967 or <code>/special/data</code>.</p>
2969 <div class="note"><p>If the intent is that a URL <strong>starts with</strong>
2970 <code>/extra/data</code>, rather than merely
2971 <strong>contains</strong> <code>/extra/data</code>, prefix the
2972 regular expression with a <code>^</code> to require this.</p>
2974 <pre class="prettyprint lang-config"><LocationMatch "^/(extra|special)/data"></pre>
2978 <p>From 2.4.8 onwards, named groups and backreferences are captured and
2979 written to the environment with the corresponding name prefixed with
2980 "MATCH_" and in upper case. This allows elements of URLs to be referenced
2981 from within <a href="../expr.html">expressions</a> and modules like
2982 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
2983 (unnamed) backreferences are ignored. Use named groups instead.</p>
2985 <pre class="prettyprint lang-config"><LocationMatch "^/combined/(?<sitename>[^/]+)">
2986 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
2987 </LocationMatch></pre>
2992 <li><a href="../sections.html">How <Directory>, <Location>
2993 and <Files> sections work</a> for an explanation of how these
2994 different sections are combined when a request is received</li>
2997 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2998 <div class="directive-section"><h2><a name="LogLevel" id="LogLevel">LogLevel</a> <a name="loglevel" id="loglevel">Directive</a></h2>
2999 <table class="directive">
3000 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Controls the verbosity of the ErrorLog</td></tr>
3001 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel [<var>module</var>:]<var>level</var>
3002 [<var>module</var>:<var>level</var>] ...
3004 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LogLevel warn</code></td></tr>
3005 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3006 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3007 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3008 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Per-module and per-directory configuration is available in
3009 Apache HTTP Server 2.3.6 and later</td></tr>
3011 <p><code class="directive">LogLevel</code> adjusts the verbosity of the
3012 messages recorded in the error logs (see <code class="directive"><a href="#errorlog">ErrorLog</a></code> directive). The following
3013 <var>level</var>s are available, in order of decreasing
3016 <table class="bordered">
3019 <th><strong>Level</strong> </th>
3021 <th><strong>Description</strong> </th>
3023 <th><strong>Example</strong> </th>
3027 <td><code>emerg</code> </td>
3029 <td>Emergencies - system is unusable.</td>
3031 <td>"Child cannot open lock file. Exiting"</td>
3035 <td><code>alert</code> </td>
3037 <td>Action must be taken immediately.</td>
3039 <td>"getpwuid: couldn't determine user name from uid"</td>
3043 <td><code>crit</code> </td>
3045 <td>Critical Conditions.</td>
3047 <td>"socket: Failed to get a socket, exiting child"</td>
3051 <td><code>error</code> </td>
3053 <td>Error conditions.</td>
3055 <td>"Premature end of script headers"</td>
3059 <td><code>warn</code> </td>
3061 <td>Warning conditions.</td>
3063 <td>"child process 1234 did not exit, sending another
3068 <td><code>notice</code> </td>
3070 <td>Normal but significant condition.</td>
3072 <td>"httpd: caught SIGBUS, attempting to dump core in
3077 <td><code>info</code> </td>
3079 <td>Informational.</td>
3081 <td>"Server seems busy, (you may need to increase
3082 StartServers, or Min/MaxSpareServers)..."</td>
3086 <td><code>debug</code> </td>
3088 <td>Debug-level messages</td>
3090 <td>"Opening config file ..."</td>
3093 <td><code>trace1</code> </td>
3095 <td>Trace messages</td>
3097 <td>"proxy: FTP: control connection complete"</td>
3100 <td><code>trace2</code> </td>
3102 <td>Trace messages</td>
3104 <td>"proxy: CONNECT: sending the CONNECT request to the remote proxy"</td>
3107 <td><code>trace3</code> </td>
3109 <td>Trace messages</td>
3111 <td>"openssl: Handshake: start"</td>
3114 <td><code>trace4</code> </td>
3116 <td>Trace messages</td>
3118 <td>"read from buffered SSL brigade, mode 0, 17 bytes"</td>
3121 <td><code>trace5</code> </td>
3123 <td>Trace messages</td>
3125 <td>"map lookup FAILED: map=rewritemap key=keyname"</td>
3128 <td><code>trace6</code> </td>
3130 <td>Trace messages</td>
3132 <td>"cache lookup FAILED, forcing new map lookup"</td>
3135 <td><code>trace7</code> </td>
3137 <td>Trace messages, dumping large amounts of data</td>
3139 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
3142 <td><code>trace8</code> </td>
3144 <td>Trace messages, dumping large amounts of data</td>
3146 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
3150 <p>When a particular level is specified, messages from all
3151 other levels of higher significance will be reported as well.
3152 <em>E.g.</em>, when <code>LogLevel info</code> is specified,
3153 then messages with log levels of <code>notice</code> and
3154 <code>warn</code> will also be posted.</p>
3156 <p>Using a level of at least <code>crit</code> is
3161 <pre class="prettyprint lang-config">LogLevel notice</pre>
3164 <div class="note"><h3>Note</h3>
3165 <p>When logging to a regular file, messages of the level
3166 <code>notice</code> cannot be suppressed and thus are always
3167 logged. However, this doesn't apply when logging is done
3168 using <code>syslog</code>.</p>
3171 <p>Specifying a level without a module name will reset the level
3172 for all modules to that level. Specifying a level with a module
3173 name will set the level for that module only. It is possible to
3174 use the module source file name, the module identifier, or the
3175 module identifier with the trailing <code>_module</code> omitted
3176 as module specification. This means the following three specifications
3179 <pre class="prettyprint lang-config">LogLevel info ssl:warn
3180 LogLevel info mod_ssl.c:warn
3181 LogLevel info ssl_module:warn</pre>
3184 <p>It is also possible to change the level per directory:</p>
3186 <pre class="prettyprint lang-config">LogLevel info
3187 <Directory "/usr/local/apache/htdocs/app">
3189 </Directory></pre>
3193 Per directory loglevel configuration only affects messages that are
3194 logged after the request has been parsed and that are associated with
3195 the request. Log messages which are associated with the server or
3196 the connection are not affected. The latter can be influenced by the
3197 <code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code> directive,
3203 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
3204 <li><code class="directive"><a href="#errorlogformat">ErrorLogFormat</a></code></li>
3205 <li><code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code></li>
3206 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
3209 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3210 <div class="directive-section"><h2><a name="LogLevelOverride" id="LogLevelOverride">LogLevelOverride</a> <a name="logleveloverride" id="logleveloverride">Directive</a></h2>
3211 <table class="directive">
3212 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Override the verbosity of the ErrorLog for certain clients</td></tr>
3213 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel <var>ipaddress</var>[/<var>prefixlen</var>]
3214 [<var>module</var>:]<var>level</var> [<var>module</var>:<var>level</var>] ...
3216 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>unset</code></td></tr>
3217 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3218 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3219 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3220 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.5.0 and later</td></tr>
3222 <p><code class="directive">LogLevelOverride</code> adjusts the
3223 <code class="directive"><a href="#loglevel">LogLevel</a></code> for requests coming from
3224 certain client IP addresses.
3225 This allows to enable verbose logging only for certain test clients.
3226 The IP address is checked at a very early state in the connection
3227 processing. Therefore, <code class="directive">LogLevelOverride</code> allows to
3228 change the log level for things like the SSL handshake which happen before
3229 a <code class="directive"><a href="#loglevel">LogLevel</a></code> directive in an
3230 <code class="directive"><a href="#if"><If></a></code> container would
3233 <p><code class="directive">LogLevelOverride</code> accepts either a single
3234 IP-address or a CIDR IP-address/len subnet specification.
3235 For the syntax of the loglevel specification, see the
3236 <code class="directive"><a href="#loglevel">LogLevel</a></code> directive.</p>
3238 <p>For requests that match a <code class="directive">LogLevelOverride</code>
3239 directive, per-directory specifications of
3240 <code class="directive"><a href="#loglevel">LogLevel</a></code> are ignored.</p>
3244 <pre class="prettyprint lang-config"> LogLevelOverride 192.0.2.0/24 ssl:trace6
3245 LogLevelOverride 192.0.2.7 ssl:trace8</pre>
3249 <code class="directive">LogLevelOverride</code> only affects
3250 log messages that are associated with the request or the connection.
3251 Log messages which are associated with the server are not affected.
3257 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
3260 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3261 <div class="directive-section"><h2><a name="MaxKeepAliveRequests" id="MaxKeepAliveRequests">MaxKeepAliveRequests</a> <a name="maxkeepaliverequests" id="maxkeepaliverequests">Directive</a></h2>
3262 <table class="directive">
3263 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of requests allowed on a persistent
3264 connection</td></tr>
3265 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxKeepAliveRequests <var>number</var></code></td></tr>
3266 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxKeepAliveRequests 100</code></td></tr>
3267 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3268 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3269 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3271 <p>The <code class="directive">MaxKeepAliveRequests</code> directive
3272 limits the number of requests allowed per connection when
3273 <code class="directive"><a href="#keepalive">KeepAlive</a></code> is on. If it is
3274 set to <code>0</code>, unlimited requests will be allowed. We
3275 recommend that this setting be kept to a high value for maximum
3276 server performance.</p>
3280 <pre class="prettyprint lang-config">MaxKeepAliveRequests 500</pre>
3284 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3285 <div class="directive-section"><h2><a name="MaxRangeOverlaps" id="MaxRangeOverlaps">MaxRangeOverlaps</a> <a name="maxrangeoverlaps" id="maxrangeoverlaps">Directive</a></h2>
3286 <table class="directive">
3287 <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
3289 <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>
3290 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeOverlaps 20</code></td></tr>
3291 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3292 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3293 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3294 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3296 <p>The <code class="directive">MaxRangeOverlaps</code> directive
3297 limits the number of overlapping HTTP ranges the server is willing to
3298 return to the client. If more overlapping ranges than permitted are requested,
3299 the complete resource is returned instead.</p>
3302 <dt><strong>default</strong></dt>
3303 <dd>Limits the number of overlapping ranges to a compile-time default of 20.</dd>
3305 <dt><strong>none</strong></dt>
3306 <dd>No overlapping Range headers are allowed.</dd>
3308 <dt><strong>unlimited</strong></dt>
3309 <dd>The server does not limit the number of overlapping ranges it is
3310 willing to satisfy.</dd>
3312 <dt><var>number-of-ranges</var></dt>
3313 <dd>A positive number representing the maximum number of overlapping ranges the
3314 server is willing to satisfy.</dd>
3318 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3319 <div class="directive-section"><h2><a name="MaxRangeReversals" id="MaxRangeReversals">MaxRangeReversals</a> <a name="maxrangereversals" id="maxrangereversals">Directive</a></h2>
3320 <table class="directive">
3321 <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
3323 <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>
3324 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeReversals 20</code></td></tr>
3325 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3326 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3327 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3328 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3330 <p>The <code class="directive">MaxRangeReversals</code> directive
3331 limits the number of HTTP Range reversals the server is willing to
3332 return to the client. If more ranges reversals than permitted are requested,
3333 the complete resource is returned instead.</p>
3336 <dt><strong>default</strong></dt>
3337 <dd>Limits the number of range reversals to a compile-time default of 20.</dd>
3339 <dt><strong>none</strong></dt>
3340 <dd>No Range reversals headers are allowed.</dd>
3342 <dt><strong>unlimited</strong></dt>
3343 <dd>The server does not limit the number of range reversals it is
3344 willing to satisfy.</dd>
3346 <dt><var>number-of-ranges</var></dt>
3347 <dd>A positive number representing the maximum number of range reversals the
3348 server is willing to satisfy.</dd>
3352 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3353 <div class="directive-section"><h2><a name="MaxRanges" id="MaxRanges">MaxRanges</a> <a name="maxranges" id="maxranges">Directive</a></h2>
3354 <table class="directive">
3355 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of ranges allowed before returning the complete
3357 <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>
3358 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRanges 200</code></td></tr>
3359 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3360 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3361 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3362 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3364 <p>The <code class="directive">MaxRanges</code> directive
3365 limits the number of HTTP ranges the server is willing to
3366 return to the client. If more ranges than permitted are requested,
3367 the complete resource is returned instead.</p>
3370 <dt><strong>default</strong></dt>
3371 <dd>Limits the number of ranges to a compile-time default of 200.</dd>
3373 <dt><strong>none</strong></dt>
3374 <dd>Range headers are ignored.</dd>
3376 <dt><strong>unlimited</strong></dt>
3377 <dd>The server does not limit the number of ranges it is
3378 willing to satisfy.</dd>
3380 <dt><var>number-of-ranges</var></dt>
3381 <dd>A positive number representing the maximum number of ranges the
3382 server is willing to satisfy.</dd>
3386 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3387 <div class="directive-section"><h2><a name="MergeTrailers" id="MergeTrailers">MergeTrailers</a> <a name="mergetrailers" id="mergetrailers">Directive</a></h2>
3388 <table class="directive">
3389 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines whether trailers are merged into headers</td></tr>
3390 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MergeTrailers [on|off]</code></td></tr>
3391 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MergeTrailers off</code></td></tr>
3392 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3393 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3394 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3395 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.4.11 and later</td></tr>
3397 <p>This directive controls whether HTTP trailers are copied into the
3398 internal representation of HTTP headers. This merging occurs when the
3399 request body has been completely consumed, long after most header
3400 processing would have a chance to examine or modify request headers.</p>
3401 <p>This option is provided for compatibility with releases prior to 2.4.11,
3402 where trailers were always merged.</p>
3405 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3406 <div class="directive-section"><h2><a name="Mutex" id="Mutex">Mutex</a> <a name="mutex" id="mutex">Directive</a></h2>
3407 <table class="directive">
3408 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures mutex mechanism and lock file directory for all
3409 or specified mutexes</td></tr>
3410 <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>
3411 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Mutex default</code></td></tr>
3412 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3413 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3414 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3415 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.4 and later</td></tr>
3417 <p>The <code class="directive">Mutex</code> directive sets the mechanism,
3418 and optionally the lock file location, that httpd and modules use
3419 to serialize access to resources. Specify <code>default</code> as
3420 the second argument to change the settings for all mutexes; specify
3421 a mutex name (see table below) as the second argument to override
3422 defaults only for that mutex.</p>
3424 <p>The <code class="directive">Mutex</code> directive is typically used in
3425 the following exceptional situations:</p>
3428 <li>change the mutex mechanism when the default mechanism selected
3429 by <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> has a functional or performance
3432 <li>change the directory used by file-based mutexes when the
3433 default directory does not support locking</li>
3436 <div class="note"><h3>Supported modules</h3>
3437 <p>This directive only configures mutexes which have been registered
3438 with the core server using the <code>ap_mutex_register()</code> API.
3439 All modules bundled with httpd support the <code class="directive">Mutex</code>
3440 directive, but third-party modules may not. Consult the documentation
3441 of the third-party module, which must indicate the mutex name(s) which
3442 can be configured if this directive is supported.</p>
3445 <p>The following mutex <em>mechanisms</em> are available:</p>
3447 <li><code>default | yes</code>
3448 <p>This selects the default locking implementation, as determined by
3449 <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a>. The default locking implementation can
3450 be displayed by running <code class="program"><a href="../programs/httpd.html">httpd</a></code> with the
3451 <code>-V</code> option.</p></li>
3453 <li><code>none | no</code>
3454 <p>This effectively disables the mutex, and is only allowed for a
3455 mutex if the module indicates that it is a valid choice. Consult the
3456 module documentation for more information.</p></li>
3458 <li><code>posixsem</code>
3459 <p>This is a mutex variant based on a Posix semaphore.</p>
3461 <div class="warning"><h3>Warning</h3>
3462 <p>The semaphore ownership is not recovered if a thread in the process
3463 holding the mutex segfaults, resulting in a hang of the web server.</p>
3467 <li><code>sysvsem</code>
3468 <p>This is a mutex variant based on a SystemV IPC semaphore.</p>
3470 <div class="warning"><h3>Warning</h3>
3471 <p>It is possible to "leak" SysV semaphores if processes crash
3472 before the semaphore is removed.</p>
3475 <div class="warning"><h3>Security</h3>
3476 <p>The semaphore API allows for a denial of service attack by any
3477 CGIs running under the same uid as the webserver (<em>i.e.</em>,
3478 all CGIs, unless you use something like <code class="program"><a href="../programs/suexec.html">suexec</a></code>
3479 or <code>cgiwrapper</code>).</p>
3483 <li><code>sem</code>
3484 <p>This selects the "best" available semaphore implementation, choosing
3485 between Posix and SystemV IPC semaphores, in that order.</p></li>
3487 <li><code>pthread</code>
3488 <p>This is a mutex variant based on cross-process Posix thread
3491 <div class="warning"><h3>Warning</h3>
3492 <p>On most systems, if a child process terminates abnormally while
3493 holding a mutex that uses this implementation, the server will deadlock
3494 and stop responding to requests. When this occurs, the server will
3495 require a manual restart to recover.</p>
3496 <p>Solaris and Linux are notable exceptions as they provide a mechanism which
3497 usually allows the mutex to be recovered after a child process
3498 terminates abnormally while holding a mutex.</p>
3499 <p>If your system is POSIX compliant or if it implements the
3500 <code>pthread_mutexattr_setrobust_np()</code> function, you may be able
3501 to use the <code>pthread</code> option safely.</p>
3505 <li><code>fcntl:/path/to/mutex</code>
3506 <p>This is a mutex variant where a physical (lock-)file and the
3507 <code>fcntl()</code> function are used as the mutex.</p>
3509 <div class="warning"><h3>Warning</h3>
3510 <p>When multiple mutexes based on this mechanism are used within
3511 multi-threaded, multi-process environments, deadlock errors (EDEADLK)
3512 can be reported for valid mutex operations if <code>fcntl()</code>
3513 is not thread-aware, such as on Solaris.</p>
3517 <li><code>flock:/path/to/mutex</code>
3518 <p>This is similar to the <code>fcntl:/path/to/mutex</code> method
3519 with the exception that the <code>flock()</code> function is used to
3520 provide file locking.</p></li>
3522 <li><code>file:/path/to/mutex</code>
3523 <p>This selects the "best" available file locking implementation,
3524 choosing between <code>fcntl</code> and <code>flock</code>, in that
3528 <p>Most mechanisms are only available on selected platforms, where the
3529 underlying platform and <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> support it. Mechanisms
3530 which aren't available on all platforms are <em>posixsem</em>,
3531 <em>sysvsem</em>, <em>sem</em>, <em>pthread</em>, <em>fcntl</em>,
3532 <em>flock</em>, and <em>file</em>.</p>
3534 <p>With the file-based mechanisms <em>fcntl</em> and <em>flock</em>,
3535 the path, if provided, is a directory where the lock file will be created.
3536 The default directory is httpd's run-time file directory,
3537 <code class="directive"><a href="#defaultruntimedir">DefaultRuntimeDir</a></code>. If a relative
3538 path is provided, it is relative to
3539 <code class="directive"><a href="#defaultruntimedir">DefaultRuntimeDir</a></code>. Always use a local
3540 disk filesystem for <code>/path/to/mutex</code> and never a directory residing
3541 on a NFS- or AFS-filesystem. The basename of the file will be the mutex
3542 type, an optional instance string provided by the module, and unless the
3543 <code>OmitPID</code> keyword is specified, the process id of the httpd
3544 parent process will be appended to make the file name unique, avoiding
3545 conflicts when multiple httpd instances share a lock file directory. For
3546 example, if the mutex name is <code>mpm-accept</code> and the lock file
3547 directory is <code>/var/httpd/locks</code>, the lock file name for the
3548 httpd instance with parent process id 12345 would be
3549 <code>/var/httpd/locks/mpm-accept.12345</code>.</p>
3551 <div class="warning"><h3>Security</h3>
3552 <p>It is best to <em>avoid</em> putting mutex files in a world-writable
3553 directory such as <code>/var/tmp</code> because someone could create
3554 a denial of service attack and prevent the server from starting by
3555 creating a lockfile with the same name as the one the server will try
3559 <p>The following table documents the names of mutexes used by httpd
3560 and bundled modules.</p>
3562 <table class="bordered"><tr class="header">
3565 <th>Protected resource</th>
3568 <td><code>mpm-accept</code></td>
3569 <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>
3570 <td>incoming connections, to avoid the thundering herd problem;
3571 for more information, refer to the
3572 <a href="../misc/perf-tuning.html">performance tuning</a>
3576 <td><code>authdigest-client</code></td>
3577 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3578 <td>client list in shared memory</td>
3581 <td><code>authdigest-opaque</code></td>
3582 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3583 <td>counter in shared memory</td>
3586 <td><code>ldap-cache</code></td>
3587 <td><code class="module"><a href="../mod/mod_ldap.html">mod_ldap</a></code></td>
3588 <td>LDAP result cache</td>
3591 <td><code>rewrite-map</code></td>
3592 <td><code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code></td>
3593 <td>communication with external mapping programs, to avoid
3594 intermixed I/O from multiple requests</td>
3597 <td><code>ssl-cache</code></td>
3598 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3599 <td>SSL session cache</td>
3602 <td><code>ssl-stapling</code></td>
3603 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3604 <td>OCSP stapling response cache</td>
3607 <td><code>watchdog-callback</code></td>
3608 <td><code class="module"><a href="../mod/mod_watchdog.html">mod_watchdog</a></code></td>
3609 <td>callback function of a particular client module</td>
3613 <p>The <code>OmitPID</code> keyword suppresses the addition of the httpd
3614 parent process id from the lock file name.</p>
3616 <p>In the following example, the mutex mechanism for the MPM accept
3617 mutex will be changed from the compiled-in default to <code>fcntl</code>,
3618 with the associated lock file created in directory
3619 <code>/var/httpd/locks</code>. The mutex mechanism for all other mutexes
3620 will be changed from the compiled-in default to <code>sysvsem</code>.</p>
3622 <pre class="prettyprint lang-config">Mutex sysvsem default
3623 Mutex fcntl:/var/httpd/locks mpm-accept</pre>
3627 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3628 <div class="directive-section"><h2><a name="NameVirtualHost" id="NameVirtualHost">NameVirtualHost</a> <a name="namevirtualhost" id="namevirtualhost">Directive</a></h2>
3629 <table class="directive">
3630 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>DEPRECATED: Designates an IP address for name-virtual
3632 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NameVirtualHost <var>addr</var>[:<var>port</var>]</code></td></tr>
3633 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3634 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3635 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3638 <p>Prior to 2.3.11, <code class="directive">NameVirtualHost</code> was required
3639 to instruct the server that a particular IP address and port combination
3640 was usable as a name-based virtual host. In 2.3.11 and later,
3641 any time an IP address and port combination is used in multiple virtual
3642 hosts, name-based virtual hosting is automatically enabled for that address.</p>
3644 <p>This directive currently has no effect.</p>
3648 <li><a href="../vhosts/">Virtual Hosts
3649 documentation</a></li>
3652 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3653 <div class="directive-section"><h2><a name="Options" id="Options">Options</a> <a name="options" id="options">Directive</a></h2>
3654 <table class="directive">
3655 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures what features are available in a particular
3657 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Options
3658 [+|-]<var>option</var> [[+|-]<var>option</var>] ...</code></td></tr>
3659 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Options FollowSymlinks</code></td></tr>
3660 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3661 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
3662 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3663 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3664 <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>
3666 <p>The <code class="directive">Options</code> directive controls which
3667 server features are available in a particular directory.</p>
3669 <p><var>option</var> can be set to <code>None</code>, in which
3670 case none of the extra features are enabled, or one or more of
3674 <dt><code>All</code></dt>
3676 <dd>All options except for <code>MultiViews</code>.</dd>
3678 <dt><code>ExecCGI</code></dt>
3681 Execution of CGI scripts using <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>
3684 <dt><code>FollowSymLinks</code></dt>
3687 The server will follow symbolic links in this directory. This is
3688 the default setting.
3690 <p>Even though the server follows the symlink it does <em>not</em>
3691 change the pathname used to match against <code class="directive"><a href="#directory"><Directory></a></code> sections.</p>
3693 <p>The <code>FollowSymLinks</code> and
3694 <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
3695 <code>.htaccess</code> files.</p>
3697 <p>Omitting this option should not be considered a security restriction,
3698 since symlink testing is subject to race conditions that make it
3702 <dt><code>Includes</code></dt>
3705 Server-side includes provided by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
3708 <dt><code>IncludesNOEXEC</code></dt>
3712 Server-side includes are permitted, but the <code>#exec
3713 cmd</code> and <code>#exec cgi</code> are disabled. It is still
3714 possible to <code>#include virtual</code> CGI scripts from
3715 <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>ed
3718 <dt><code>Indexes</code></dt>
3721 If a URL which maps to a directory is requested and there
3722 is no <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
3723 (<em>e.g.</em>, <code>index.html</code>) in that directory, then
3724 <code class="module"><a href="../mod/mod_autoindex.html">mod_autoindex</a></code> will return a formatted listing
3725 of the directory.</dd>
3727 <dt><code>MultiViews</code></dt>
3730 <a href="../content-negotiation.html">Content negotiated</a>
3731 "MultiViews" are allowed using
3732 <code class="module"><a href="../mod/mod_negotiation.html">mod_negotiation</a></code>.
3733 <div class="note"><h3>Note</h3> <p>This option gets ignored if set
3734 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>
3735 needs real resources to compare against and evaluate from.</p></div>
3738 <dt><code>SymLinksIfOwnerMatch</code></dt>
3740 <dd>The server will only follow symbolic links for which the
3741 target file or directory is owned by the same user id as the
3744 <div class="note"><h3>Note</h3>
3745 <p>The <code>FollowSymLinks</code> and
3746 <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
3747 <code>.htaccess</code> files.</p>
3749 <p>This option should not be considered a security restriction,
3750 since symlink testing is subject to race conditions that make it
3755 <p>Normally, if multiple <code class="directive">Options</code> could
3756 apply to a directory, then the most specific one is used and
3757 others are ignored; the options are not merged. (See <a href="../sections.html#merging">how sections are merged</a>.)
3758 However if <em>all</em> the options on the
3759 <code class="directive">Options</code> directive are preceded by a
3760 <code>+</code> or <code>-</code> symbol, the options are
3761 merged. Any options preceded by a <code>+</code> are added to the
3762 options currently in force, and any options preceded by a
3763 <code>-</code> are removed from the options currently in
3766 <div class="note"><h3>Note</h3>
3767 <p>Mixing <code class="directive">Options</code> with a <code>+</code> or
3768 <code>-</code> with those without is not valid syntax and will be
3769 rejected during server startup by the syntax check with an abort.</p>
3772 <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>
3774 <pre class="prettyprint lang-config"><Directory "/web/docs">
3775 Options Indexes FollowSymLinks
3778 <Directory "/web/docs/spec">
3780 </Directory></pre>
3783 <p>then only <code>Includes</code> will be set for the
3784 <code>/web/docs/spec</code> directory. However if the second
3785 <code class="directive">Options</code> directive uses the <code>+</code> and
3786 <code>-</code> symbols:</p>
3788 <pre class="prettyprint lang-config"><Directory "/web/docs">
3789 Options Indexes FollowSymLinks
3792 <Directory "/web/docs/spec">
3793 Options +Includes -Indexes
3794 </Directory></pre>
3797 <p>then the options <code>FollowSymLinks</code> and
3798 <code>Includes</code> are set for the <code>/web/docs/spec</code>
3801 <div class="note"><h3>Note</h3>
3802 <p>Using <code>-IncludesNOEXEC</code> or
3803 <code>-Includes</code> disables server-side includes completely
3804 regardless of the previous setting.</p>
3807 <p>The default in the absence of any other settings is
3808 <code>FollowSymlinks</code>.</p>
3811 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3812 <div class="directive-section"><h2><a name="Protocol" id="Protocol">Protocol</a> <a name="protocol" id="protocol">Directive</a></h2>
3813 <table class="directive">
3814 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Protocol for a listening socket</td></tr>
3815 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Protocol <var>protocol</var></code></td></tr>
3816 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3817 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3818 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3819 <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>
3821 <p>This directive specifies the protocol used for a specific listening socket.
3822 The protocol is used to determine which module should handle a request and
3823 to apply protocol specific optimizations with the <code class="directive">AcceptFilter</code>
3826 <p>You only need to set the protocol if you are running on non-standard ports;
3827 otherwise, <code>http</code> is assumed for port 80 and <code>https</code>
3830 <p>For example, if you are running <code>https</code> on a non-standard port,
3831 specify the protocol explicitly:</p>
3833 <pre class="prettyprint lang-config">Protocol https</pre>
3836 <p>You can also specify the protocol using the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code> directive.</p>
3840 <li><code class="directive"><a href="#acceptfilter">AcceptFilter</a></code></li>
3841 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
3844 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3845 <div class="directive-section"><h2><a name="Protocols" id="Protocols">Protocols</a> <a name="protocols" id="protocols">Directive</a></h2>
3846 <table class="directive">
3847 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Protocols available for a server/virtual host</td></tr>
3848 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Protocols <var>protocol</var> ...</code></td></tr>
3849 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Protocols http/1.1</code></td></tr>
3850 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3851 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3852 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3853 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Only available from Apache 2.4.17 and later.</td></tr>
3855 <p>This directive specifies the list of protocols supported for a
3856 server/virtual host. The list determines the allowed protocols
3857 a client may negotiate for this server/host.</p>
3859 <p>You need to set protocols if you want to extend the available
3860 protocols for a server/host. By default, only the http/1.1 protocol
3861 (which includes the compatibility with 1.0 and 0.9 clients) is
3864 <p>For example, if you want to support HTTP/2 for a server with TLS,
3867 <pre class="prettyprint lang-config">Protocols h2 http/1.1</pre>
3870 <p>Valid protocols are <code>http/1.1</code> for http and https connections,
3871 <code>h2</code> on https connections and <code>h2c</code> for http
3872 connections. Modules may enable more protocols.</p>
3874 <p>It is safe to specify protocols that are unavailable/disabled. Such
3875 protocol names will simply be ignored.</p>
3877 <p>Protocols specified in base servers are inherited for virtual hosts
3878 only if the virtual host has no own Protocols directive. Or, the other
3879 way around, Protocols directives in virtual hosts replace any
3880 such directive in the base server.
3886 <li><code class="directive"><a href="#protocolshonororder">ProtocolsHonorOrder</a></code></li>
3889 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3890 <div class="directive-section"><h2><a name="ProtocolsHonorOrder" id="ProtocolsHonorOrder">ProtocolsHonorOrder</a> <a name="protocolshonororder" id="protocolshonororder">Directive</a></h2>
3891 <table class="directive">
3892 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines if order of Protocols determines precedence during negotiation</td></tr>
3893 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProtocolsHonorOrder On|Off</code></td></tr>
3894 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProtocolsHonorOrder On</code></td></tr>
3895 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3896 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3897 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3898 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Only available from Apache 2.4.17 and later.</td></tr>
3900 <p>This directive specifies if the server should honor the order in which
3901 the <code class="directive">Protocols</code> directive lists protocols.</p>
3903 <p>If configured Off, the client supplied list order of protocols has
3904 precedence over the order in the server configuration.</p>
3906 <p>With <code class="directive">ProtocolsHonorOrder</code> set to <code>on</code>
3907 (default), the client ordering does not matter and only the ordering
3908 in the server settings influences the outcome of the protocol
3914 <li><code class="directive"><a href="#protocols">Protocols</a></code></li>
3917 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3918 <div class="directive-section"><h2><a name="QualifyRedirectURL" id="QualifyRedirectURL">QualifyRedirectURL</a> <a name="qualifyredirecturl" id="qualifyredirecturl">Directive</a></h2>
3919 <table class="directive">
3920 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Controls whether the REDIRECT_URL environment variable is
3921 fully qualified</td></tr>
3922 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>QualifyRedirectURL ON|OFF</code></td></tr>
3923 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>QualifyRedirectURL OFF</code></td></tr>
3924 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3925 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3926 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3927 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3928 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Directive supported in 2.4.18 and later. 2.4.17 acted
3929 as if 'QualifyRedirectURL ON' was configured.</td></tr>
3931 <p>This directive controls whether the server will ensure that the
3932 REDIRECT_URL environment variable is fully qualified. By default,
3933 the variable contains the verbatim URL requested by the client,
3934 such as "/index.html". With <code class="directive"><a href="#qualifyredirecturl on">QualifyRedirectURL ON</a></code>, the same request would result in a
3935 value such as "http://www.example.com/index.html".</p>
3936 <p>Even without this directive set, when a request is issued against a
3937 fully qualified URL, REDIRECT_URL will remain fully qualified.
3941 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3942 <div class="directive-section"><h2><a name="RegisterHttpMethod" id="RegisterHttpMethod">RegisterHttpMethod</a> <a name="registerhttpmethod" id="registerhttpmethod">Directive</a></h2>
3943 <table class="directive">
3944 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Register non-standard HTTP methods</td></tr>
3945 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>RegisterHttpMethod <var>method</var> [<var>method</var> [...]]</code></td></tr>
3946 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3947 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3948 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3950 <p>HTTP Methods that are not conforming to the relevant RFCs are normally
3951 rejected by request processing in Apache HTTPD. To avoid this, modules
3952 can register non-standard HTTP methods they support.
3953 The <code class="directive">RegisterHttpMethod</code> allows to register such
3954 methods manually. This can be useful if such methods are forwarded
3955 for external processing, e.g. to a CGI script.</p>
3958 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3959 <div class="directive-section"><h2><a name="RLimitCPU" id="RLimitCPU">RLimitCPU</a> <a name="rlimitcpu" id="rlimitcpu">Directive</a></h2>
3960 <table class="directive">
3961 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the CPU consumption of processes launched
3962 by Apache httpd children</td></tr>
3963 <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>
3964 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3965 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3966 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3967 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3968 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3970 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3971 resource limit for all processes and the second parameter sets
3972 the maximum resource limit. Either parameter can be a number,
3973 or <code>max</code> to indicate to the server that the limit should
3974 be set to the maximum allowed by the operating system
3975 configuration. Raising the maximum resource limit requires that
3976 the server is running as <code>root</code> or in the initial startup
3979 <p>This applies to processes forked from Apache httpd children
3980 servicing requests, not the Apache httpd children themselves. This
3981 includes CGI scripts and SSI exec commands, but not any
3982 processes forked from the Apache httpd parent, such as piped
3985 <p>CPU resource limits are expressed in seconds per
3990 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3991 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3994 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3995 <div class="directive-section"><h2><a name="RLimitMEM" id="RLimitMEM">RLimitMEM</a> <a name="rlimitmem" id="rlimitmem">Directive</a></h2>
3996 <table class="directive">
3997 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the memory consumption of processes launched
3998 by Apache httpd children</td></tr>
3999 <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>
4000 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
4001 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4002 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
4003 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4004 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4006 <p>Takes 1 or 2 parameters. The first parameter sets the soft
4007 resource limit for all processes and the second parameter sets
4008 the maximum resource limit. Either parameter can be a number,
4009 or <code>max</code> to indicate to the server that the limit should
4010 be set to the maximum allowed by the operating system
4011 configuration. Raising the maximum resource limit requires that
4012 the server is running as <code>root</code> or in the initial startup
4015 <p>This applies to processes forked from Apache httpd children
4016 servicing requests, not the Apache httpd children themselves. This
4017 includes CGI scripts and SSI exec commands, but not any
4018 processes forked from the Apache httpd parent, such as piped
4021 <p>Memory resource limits are expressed in bytes per
4026 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
4027 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
4030 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4031 <div class="directive-section"><h2><a name="RLimitNPROC" id="RLimitNPROC">RLimitNPROC</a> <a name="rlimitnproc" id="rlimitnproc">Directive</a></h2>
4032 <table class="directive">
4033 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of processes that can be launched by
4034 processes launched by Apache httpd children</td></tr>
4035 <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>
4036 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
4037 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4038 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
4039 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4040 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4042 <p>Takes 1 or 2 parameters. The first parameter sets the soft
4043 resource limit for all processes, and the second parameter sets
4044 the maximum resource limit. Either parameter can be a number,
4045 or <code>max</code> to indicate to the server that the limit
4046 should be set to the maximum allowed by the operating system
4047 configuration. Raising the maximum resource limit requires that
4048 the server is running as <code>root</code> or in the initial startup
4051 <p>This applies to processes forked from Apache httpd children
4052 servicing requests, not the Apache httpd children themselves. This
4053 includes CGI scripts and SSI exec commands, but not any
4054 processes forked from the Apache httpd parent, such as piped
4057 <p>Process limits control the number of processes per user.</p>
4059 <div class="note"><h3>Note</h3>
4060 <p>If CGI processes are <strong>not</strong> running
4061 under user ids other than the web server user id, this directive
4062 will limit the number of processes that the server itself can
4063 create. Evidence of this situation will be indicated by
4064 <strong><code>cannot fork</code></strong> messages in the
4065 <code>error_log</code>.</p>
4070 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
4071 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
4074 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4075 <div class="directive-section"><h2><a name="ScriptInterpreterSource" id="ScriptInterpreterSource">ScriptInterpreterSource</a> <a name="scriptinterpretersource" id="scriptinterpretersource">Directive</a></h2>
4076 <table class="directive">
4077 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
4079 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ScriptInterpreterSource Registry|Registry-Strict|Script</code></td></tr>
4080 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ScriptInterpreterSource Script</code></td></tr>
4081 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4082 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4083 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4084 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4085 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Win32 only.</td></tr>
4087 <p>This directive is used to control how Apache httpd finds the
4088 interpreter used to run CGI scripts. The default setting is
4089 <code>Script</code>. This causes Apache httpd to use the interpreter pointed to
4090 by the shebang line (first line, starting with <code>#!</code>) in the
4091 script. On Win32 systems this line usually looks like:</p>
4093 <pre class="prettyprint lang-perl">#!C:/Perl/bin/perl.exe</pre>
4096 <p>or, if <code>perl</code> is in the <code>PATH</code>, simply:</p>
4098 <pre class="prettyprint lang-perl">#!perl</pre>
4101 <p>Setting <code>ScriptInterpreterSource Registry</code> will
4102 cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
4103 searched using the script file extension (e.g., <code>.pl</code>) as a
4104 search key. The command defined by the registry subkey
4105 <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
4106 <code>Shell\Open\Command</code> is used to open the script file. If the
4107 registry keys cannot be found, Apache httpd falls back to the behavior of the
4108 <code>Script</code> option.</p>
4110 <div class="warning"><h3>Security</h3>
4111 <p>Be careful when using <code>ScriptInterpreterSource
4112 Registry</code> with <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>'ed directories, because
4113 Apache httpd will try to execute <strong>every</strong> file within this
4114 directory. The <code>Registry</code> setting may cause undesired
4115 program calls on files which are typically not executed. For
4116 example, the default open command on <code>.htm</code> files on
4117 most Windows systems will execute Microsoft Internet Explorer, so
4118 any HTTP request for an <code>.htm</code> file existing within the
4119 script directory would start the browser in the background on the
4120 server. This is a good way to crash your system within a minute or
4124 <p>The option <code>Registry-Strict</code> which is new in Apache HTTP Server
4125 2.0 does the same thing as <code>Registry</code> but uses only the
4126 subkey <code>Shell\ExecCGI\Command</code>. The
4127 <code>ExecCGI</code> key is not a common one. It must be
4128 configured manually in the windows registry and hence prevents
4129 accidental program calls on your system.</p>
4132 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4133 <div class="directive-section"><h2><a name="SeeRequestTail" id="SeeRequestTail">SeeRequestTail</a> <a name="seerequesttail" id="seerequesttail">Directive</a></h2>
4134 <table class="directive">
4135 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine if mod_status displays the first 63 characters
4136 of a request or the last 63, assuming the request itself is greater than
4138 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SeeRequestTail On|Off</code></td></tr>
4139 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SeeRequestTail Off</code></td></tr>
4140 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4141 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4142 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4144 <p>mod_status with <code>ExtendedStatus On</code>
4145 displays the actual request being handled.
4146 For historical purposes, only 63 characters of the request
4147 are actually stored for display purposes. This directive
4148 controls whether the 1st 63 characters are stored (the previous
4149 behavior and the default) or if the last 63 characters are. This
4150 is only applicable, of course, if the length of the request is
4151 64 characters or greater.</p>
4153 <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:
4156 <table class="bordered">
4158 <th>Off (default)</th>
4159 <td>GET /disk1/storage/apache/htdocs/images/imagestore1/food/apples</td>
4163 <td>orage/apache/htdocs/images/imagestore1/food/apples.jpg HTTP/1.1</td>
4169 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4170 <div class="directive-section"><h2><a name="ServerAdmin" id="ServerAdmin">ServerAdmin</a> <a name="serveradmin" id="serveradmin">Directive</a></h2>
4171 <table class="directive">
4172 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Email address that the server includes in error
4173 messages sent to the client</td></tr>
4174 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAdmin <var>email-address</var>|<var>URL</var></code></td></tr>
4175 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</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>The <code class="directive">ServerAdmin</code> sets the contact address
4180 that the server includes in any error messages it returns to the
4181 client. If the <code>httpd</code> doesn't recognize the supplied argument
4183 assumes, that it's an <var>email-address</var> and prepends it with
4184 <code>mailto:</code> in hyperlink targets. However, it's recommended to
4185 actually use an email address, since there are a lot of CGI scripts that
4186 make that assumption. If you want to use an URL, it should point to another
4187 server under your control. Otherwise users may not be able to contact you in
4190 <p>It may be worth setting up a dedicated address for this, e.g.</p>
4192 <pre class="prettyprint lang-config">ServerAdmin www-admin@foo.example.com</pre>
4194 <p>as users do not always mention that they are talking about the
4198 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4199 <div class="directive-section"><h2><a name="ServerAlias" id="ServerAlias">ServerAlias</a> <a name="serveralias" id="serveralias">Directive</a></h2>
4200 <table class="directive">
4201 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Alternate names for a host used when matching requests
4202 to name-virtual hosts</td></tr>
4203 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</code></td></tr>
4204 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
4205 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4206 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4208 <p>The <code class="directive">ServerAlias</code> directive sets the
4209 alternate names for a host, for use with <a href="../vhosts/name-based.html">name-based virtual hosts</a>. The
4210 <code class="directive">ServerAlias</code> may include wildcards, if appropriate.</p>
4212 <pre class="prettyprint lang-config"><VirtualHost *:80>
4213 ServerName server.example.com
4214 ServerAlias server server2.example.com server2
4215 ServerAlias *.example.com
4216 UseCanonicalName Off
4218 </VirtualHost></pre>
4221 <p>Name-based virtual hosts for the best-matching set of <code class="directive"><a href="#virtualhost"><virtualhost></a></code>s are processed
4222 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
4223 (nor for ServerName vs. ServerAlias). </p>
4225 <p>The complete list of names in the <code class="directive"><a href="#virtualhost"><VirtualHost></a></code>
4226 directive are treated just like a (non wildcard)
4227 <code class="directive">ServerAlias</code>.</p>
4232 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
4233 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4236 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4237 <div class="directive-section"><h2><a name="ServerName" id="ServerName">ServerName</a> <a name="servername" id="servername">Directive</a></h2>
4238 <table class="directive">
4239 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hostname and port that the server uses to identify
4241 <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>
4242 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4243 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4244 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4246 <p>The <code class="directive">ServerName</code> directive sets the
4247 request scheme, hostname and port that the server uses to identify itself.
4250 <p><code class="directive">ServerName</code> is used (possibly
4251 in conjunction with <code class="directive"><a href="#serveralias">ServerAlias</a></code>) to uniquely
4252 identify a virtual host, when using <a href="../vhosts/name-based.html">name-based virtual hosts</a>.</p>
4254 <p>Additionally, this is used when
4255 creating self-referential redirection URLs when
4256 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> is set to a non-default
4259 <p>For example, if the name of the
4260 machine hosting the web server is <code>simple.example.com</code>,
4261 but the machine also has the DNS alias <code>www.example.com</code>
4262 and you wish the web server to be so identified, the following
4263 directive should be used:</p>
4265 <pre class="prettyprint lang-config">ServerName www.example.com</pre>
4268 <p>The <code class="directive">ServerName</code> directive
4269 may appear anywhere within the definition of a server. However,
4270 each appearance overrides the previous appearance (within that
4273 <p>If no <code class="directive">ServerName</code> is specified, the
4274 server attempts to deduce the client visible hostname by first asking
4275 the operating system for the system hostname, and if that fails,
4276 performing a reverse lookup on an IP address present on the system.</p>
4278 <p>If no port is specified in the
4279 <code class="directive">ServerName</code>, then the server will use the
4280 port from the incoming request. For optimal reliability and
4281 predictability, you should specify an explicit hostname and port
4282 using the <code class="directive">ServerName</code> directive.</p>
4284 <p>If you are using <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
4285 the <code class="directive">ServerName</code> inside a
4286 <code class="directive"><a href="#virtualhost"><VirtualHost></a></code>
4287 section specifies what hostname must appear in the request's
4288 <code>Host:</code> header to match this virtual host.</p>
4290 <p>Sometimes, the server runs behind a device that processes SSL,
4291 such as a reverse proxy, load balancer or SSL offload
4292 appliance. When this is the case, specify the
4293 <code>https://</code> scheme and the port number to which the
4294 clients connect in the <code class="directive">ServerName</code> directive
4295 to make sure that the server generates the correct
4296 self-referential URLs.
4299 <p>See the description of the
4300 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> and
4301 <code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code> directives for
4302 settings which determine whether self-referential URLs (e.g., by the
4303 <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> module) will refer to the
4304 specified port, or to the port number given in the client's request.
4307 <div class="warning">
4308 <p>Failure to set <code class="directive">ServerName</code> to a name that
4309 your server can resolve to an IP address will result in a startup
4310 warning. <code>httpd</code> will then use whatever hostname it can
4311 determine, using the system's <code>hostname</code> command. This
4312 will almost never be the hostname you actually want.</p>
4313 <div class="example"><p><code>
4314 httpd: Could not reliably determine the server's fully qualified domain name, using rocinante.local for ServerName
4321 <li><a href="../dns-caveats.html">Issues Regarding DNS and
4322 Apache HTTP Server</a></li>
4323 <li><a href="../vhosts/">Apache HTTP Server virtual host
4324 documentation</a></li>
4325 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
4326 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
4327 <li><code class="directive"><a href="#serveralias">ServerAlias</a></code></li>
4330 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4331 <div class="directive-section"><h2><a name="ServerPath" id="ServerPath">ServerPath</a> <a name="serverpath" id="serverpath">Directive</a></h2>
4332 <table class="directive">
4333 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Legacy URL pathname for a name-based virtual host that
4334 is accessed by an incompatible browser</td></tr>
4335 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerPath <var>URL-path</var></code></td></tr>
4336 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
4337 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4338 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4340 <p>The <code class="directive">ServerPath</code> directive sets the legacy
4341 URL pathname for a host, for use with <a href="../vhosts/">name-based virtual hosts</a>.</p>
4345 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4348 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4349 <div class="directive-section"><h2><a name="ServerRoot" id="ServerRoot">ServerRoot</a> <a name="serverroot" id="serverroot">Directive</a></h2>
4350 <table class="directive">
4351 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server installation</td></tr>
4352 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerRoot <var>directory-path</var></code></td></tr>
4353 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerRoot /usr/local/apache</code></td></tr>
4354 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4355 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4356 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4358 <p>The <code class="directive">ServerRoot</code> directive sets the
4359 directory in which the server lives. Typically it will contain the
4360 subdirectories <code>conf/</code> and <code>logs/</code>. Relative
4361 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
4362 relative to this directory.</p>
4364 <pre class="prettyprint lang-config">ServerRoot "/home/httpd"</pre>
4367 <p>The default location of <code class="directive">ServerRoot</code> may be
4368 modified by using the <code>--prefix</code> argument to
4369 <a href="../programs/configure.html"><code>configure</code></a>, and
4370 most third-party distributions of the server have a different
4371 default location from the one listed above.</p>
4376 <li><a href="../invoking.html">the <code>-d</code>
4377 option to <code>httpd</code></a></li>
4378 <li><a href="../misc/security_tips.html#serverroot">the
4379 security tips</a> for information on how to properly set
4380 permissions on the <code class="directive">ServerRoot</code></li>
4383 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4384 <div class="directive-section"><h2><a name="ServerSignature" id="ServerSignature">ServerSignature</a> <a name="serversignature" id="serversignature">Directive</a></h2>
4385 <table class="directive">
4386 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the footer on server-generated documents</td></tr>
4387 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerSignature On|Off|EMail</code></td></tr>
4388 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerSignature Off</code></td></tr>
4389 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4390 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
4391 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4392 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4394 <p>The <code class="directive">ServerSignature</code> directive allows the
4395 configuration of a trailing footer line under server-generated
4396 documents (error messages, <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> ftp directory
4397 listings, <code class="module"><a href="../mod/mod_info.html">mod_info</a></code> output, ...). The reason why you
4398 would want to enable such a footer line is that in a chain of proxies,
4399 the user often has no possibility to tell which of the chained servers
4400 actually produced a returned error message.</p>
4402 <p>The <code>Off</code>
4403 setting, which is the default, suppresses the footer line (and is
4404 therefore compatible with the behavior of Apache-1.2 and
4405 below). The <code>On</code> setting simply adds a line with the
4406 server version number and <code class="directive"><a href="#servername">ServerName</a></code> of the serving virtual host,
4407 and the <code>EMail</code> setting additionally creates a
4408 "mailto:" reference to the <code class="directive"><a href="#serveradmin">ServerAdmin</a></code> of the referenced
4411 <p>After version 2.0.44, the details of the server version number
4412 presented are controlled by the <code class="directive"><a href="#servertokens">ServerTokens</a></code> directive.</p>
4416 <li><code class="directive"><a href="#servertokens">ServerTokens</a></code></li>
4419 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4420 <div class="directive-section"><h2><a name="ServerTokens" id="ServerTokens">ServerTokens</a> <a name="servertokens" id="servertokens">Directive</a></h2>
4421 <table class="directive">
4422 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the <code>Server</code> HTTP response
4424 <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>
4425 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerTokens Full</code></td></tr>
4426 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4427 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4428 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4430 <p>This directive controls whether <code>Server</code> response
4431 header field which is sent back to clients includes a
4432 description of the generic OS-type of the server as well as
4433 information about compiled-in modules.</p>
4436 <dt><code>ServerTokens Full</code> (or not specified)</dt>
4438 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4439 (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
4441 <dt><code>ServerTokens Prod[uctOnly]</code></dt>
4443 <dd>Server sends (<em>e.g.</em>): <code>Server:
4446 <dt><code>ServerTokens Major</code></dt>
4448 <dd>Server sends (<em>e.g.</em>): <code>Server:
4449 Apache/2</code></dd>
4451 <dt><code>ServerTokens Minor</code></dt>
4453 <dd>Server sends (<em>e.g.</em>): <code>Server:
4454 Apache/2.4</code></dd>
4456 <dt><code>ServerTokens Min[imal]</code></dt>
4458 <dd>Server sends (<em>e.g.</em>): <code>Server:
4459 Apache/2.4.2</code></dd>
4461 <dt><code>ServerTokens OS</code></dt>
4463 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4468 <p>This setting applies to the entire server, and cannot be
4469 enabled or disabled on a virtualhost-by-virtualhost basis.</p>
4471 <p>After version 2.0.44, this directive also controls the
4472 information presented by the <code class="directive"><a href="#serversignature">ServerSignature</a></code> directive.</p>
4474 <div class="note">Setting <code class="directive">ServerTokens</code> to less than
4475 <code>minimal</code> is not recommended because it makes it more
4476 difficult to debug interoperational problems. Also note that
4477 disabling the Server: header does nothing at all to make your
4478 server more secure. The idea of "security through obscurity"
4479 is a myth and leads to a false sense of safety.</div>
4483 <li><code class="directive"><a href="#serversignature">ServerSignature</a></code></li>
4486 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4487 <div class="directive-section"><h2><a name="SetHandler" id="SetHandler">SetHandler</a> <a name="sethandler" id="sethandler">Directive</a></h2>
4488 <table class="directive">
4489 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be processed by a
4491 <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>
4492 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4493 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4494 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4495 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4496 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.5 and later</td></tr>
4498 <p>When placed into an <code>.htaccess</code> file or a
4499 <code class="directive"><a href="#directory"><Directory></a></code> or
4500 <code class="directive"><a href="#location"><Location></a></code>
4501 section, this directive forces all matching files to be parsed
4502 through the <a href="../handler.html">handler</a> given by
4503 <var>handler-name</var>. For example, if you had a directory you
4504 wanted to be parsed entirely as imagemap rule files, regardless
4505 of extension, you might put the following into an
4506 <code>.htaccess</code> file in that directory:</p>
4508 <pre class="prettyprint lang-config">SetHandler imap-file</pre>
4511 <p>Another example: if you wanted to have the server display a
4512 status report whenever a URL of
4513 <code>http://servername/status</code> was called, you might put
4514 the following into <code>httpd.conf</code>:</p>
4516 <pre class="prettyprint lang-config"><Location "/status">
4517 SetHandler server-status
4518 </Location></pre>
4521 <p>You could also use this directive to configure a particular
4522 handler for files with a particular file extension. For example:</p>
4524 <pre class="prettyprint lang-config"><FilesMatch "\.php$">
4525 SetHandler application/x-httpd-php
4526 </FilesMatch></pre>
4529 <p>String-valued expressions can be used to reference per-request
4530 variables, including backreferences to named regular expressions:</p>
4532 <pre class="prettyprint lang-config"><LocationMatch ^/app/(?<sub>[^/]+)/>
4533 SetHandler "proxy:unix:/var/run/app_%{env:MATCH_sub}.sock|fcgi://localhost:8080"
4534 </LocationMatch></pre>
4537 <p>You can override an earlier defined <code class="directive">SetHandler</code>
4538 directive by using the value <code>None</code>.</p>
4540 <div class="note"><h3>Note</h3>
4541 <p>Because <code class="directive">SetHandler</code> overrides default handlers,
4542 normal behavior such as handling of URLs ending in a slash (/) as
4543 directories or index files is suppressed.</p></div>
4547 <li><code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code></li>
4550 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4551 <div class="directive-section"><h2><a name="SetInputFilter" id="SetInputFilter">SetInputFilter</a> <a name="setinputfilter" id="setinputfilter">Directive</a></h2>
4552 <table class="directive">
4553 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process client requests and POST
4555 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetInputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4556 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4557 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4558 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4559 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4561 <p>The <code class="directive">SetInputFilter</code> directive sets the
4562 filter or filters which will process client requests and POST
4563 input when they are received by the server. This is in addition to
4564 any filters defined elsewhere, including the
4565 <code class="directive"><a href="../mod/mod_mime.html#addinputfilter">AddInputFilter</a></code>
4568 <p>If more than one filter is specified, they must be separated
4569 by semicolons in the order in which they should process the
4574 <li><a href="../filter.html">Filters</a> documentation</li>
4577 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4578 <div class="directive-section"><h2><a name="SetOutputFilter" id="SetOutputFilter">SetOutputFilter</a> <a name="setoutputfilter" id="setoutputfilter">Directive</a></h2>
4579 <table class="directive">
4580 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process responses from the
4582 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4583 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4584 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4585 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4586 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4588 <p>The <code class="directive">SetOutputFilter</code> directive sets the filters
4589 which will process responses from the server before they are
4590 sent to the client. This is in addition to any filters defined
4591 elsewhere, including the
4592 <code class="directive"><a href="../mod/mod_mime.html#addoutputfilter">AddOutputFilter</a></code>
4595 <p>For example, the following configuration will process all files
4596 in the <code>/www/data/</code> directory for server-side
4599 <pre class="prettyprint lang-config"><Directory "/www/data/">
4600 SetOutputFilter INCLUDES
4601 </Directory></pre>
4604 <p>If more than one filter is specified, they must be separated
4605 by semicolons in the order in which they should process the
4610 <li><a href="../filter.html">Filters</a> documentation</li>
4613 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4614 <div class="directive-section"><h2><a name="TimeOut" id="TimeOut">TimeOut</a> <a name="timeout" id="timeout">Directive</a></h2>
4615 <table class="directive">
4616 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for
4617 certain events before failing a request</td></tr>
4618 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TimeOut <var>seconds</var></code></td></tr>
4619 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TimeOut 60</code></td></tr>
4620 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4621 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4622 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4624 <p>The <code class="directive">TimeOut</code> directive defines the length
4625 of time Apache httpd will wait for I/O in various circumstances:</p>
4628 <li><p>When reading data from the client, the length of time to
4629 wait for a TCP packet to arrive if the read buffer is
4631 <p> For initial data on a new connection, this directive doesn't
4632 take effect until after any configured <code class="directive"><a href="#acceptfilter">
4633 AcceptFilter</a></code> has passed the new connection to the server.</p>
4636 <li>When writing data to the client, the length of time to wait
4637 for an acknowledgement of a packet if the send buffer is
4640 <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>,
4641 the length of time to wait for output from a CGI script.</li>
4643 <li>In <code class="module"><a href="../mod/mod_ext_filter.html">mod_ext_filter</a></code>, the length of time to
4644 wait for output from a filtering process.</li>
4646 <li>In <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>, the default timeout value if
4647 <code class="directive"><a href="../mod/mod_proxy.html#proxytimeout">ProxyTimeout</a></code> is not
4653 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4654 <div class="directive-section"><h2><a name="TraceEnable" id="TraceEnable">TraceEnable</a> <a name="traceenable" id="traceenable">Directive</a></h2>
4655 <table class="directive">
4656 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines the behavior on <code>TRACE</code> requests</td></tr>
4657 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TraceEnable <var>[on|off|extended]</var></code></td></tr>
4658 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TraceEnable on</code></td></tr>
4659 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4660 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4661 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4663 <p>This directive overrides the behavior of <code>TRACE</code> for both
4664 the core server and <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>. The default
4665 <code>TraceEnable on</code> permits <code>TRACE</code> requests per
4666 RFC 2616, which disallows any request body to accompany the request.
4667 <code>TraceEnable off</code> causes the core server and
4668 <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> to return a <code>405</code> (Method not
4669 allowed) error to the client.</p>
4671 <p>Finally, for testing and diagnostic purposes only, request
4672 bodies may be allowed using the non-compliant <code>TraceEnable
4673 extended</code> directive. The core (as an origin server) will
4674 restrict the request body to 64Kb (plus 8Kb for chunk headers if
4675 <code>Transfer-Encoding: chunked</code> is used). The core will
4676 reflect the full headers and all chunk headers with the response
4677 body. As a proxy server, the request body is not restricted to 64Kb.</p>
4679 <div class="note"><h3>Note</h3>
4681 <p>Despite claims to the contrary, enabling the <code>TRACE</code>
4682 method does not expose any security vulnerability in Apache httpd.
4683 The <code>TRACE</code> method is defined by the HTTP/1.1
4684 specification and implementations are expected to support it.</p>
4689 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4690 <div class="directive-section"><h2><a name="UnDefine" id="UnDefine">UnDefine</a> <a name="undefine" id="undefine">Directive</a></h2>
4691 <table class="directive">
4692 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Undefine the existence of a variable</td></tr>
4693 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UnDefine <var>parameter-name</var></code></td></tr>
4694 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4695 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4696 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4698 <p>Undoes the effect of a <code class="directive"><a href="#define">Define</a></code> or
4699 of passing a <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</p>
4700 <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
4701 <code>-D</code> arguments in any startup scripts.</p>
4702 <p>While this directive is supported in virtual host context,
4703 the changes it makes are visible to any later configuration
4704 directives, beyond any enclosing virtual host.</p>
4708 <li><code class="directive"><a href="#define">Define</a></code></li>
4709 <li><code class="directive"><a href="#ifdefine">IfDefine</a></code></li>
4712 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4713 <div class="directive-section"><h2><a name="UseCanonicalName" id="UseCanonicalName">UseCanonicalName</a> <a name="usecanonicalname" id="usecanonicalname">Directive</a></h2>
4714 <table class="directive">
4715 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own name and
4717 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalName On|Off|DNS</code></td></tr>
4718 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalName Off</code></td></tr>
4719 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4720 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4721 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4723 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4724 URL -- that is, a URL that refers back to the same server. With
4725 <code>UseCanonicalName On</code> Apache httpd will use the hostname and port
4726 specified in the <code class="directive"><a href="#servername">ServerName</a></code>
4727 directive to construct the canonical name for the server. This name
4728 is used in all self-referential URLs, and for the values of
4729 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>
4731 <p>With <code>UseCanonicalName Off</code> Apache httpd will form
4732 self-referential URLs using the hostname and port supplied by
4733 the client if any are supplied (otherwise it will use the
4734 canonical name, as defined above). These values are the same
4735 that are used to implement <a href="../vhosts/name-based.html">name-based virtual hosts</a>
4736 and are available with the same clients. The CGI variables
4737 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
4738 constructed from the client supplied values as well.</p>
4740 <p>An example where this may be useful is on an intranet server
4741 where you have users connecting to the machine using short
4742 names such as <code>www</code>. You'll notice that if the users
4743 type a shortname and a URL which is a directory, such as
4744 <code>http://www/splat</code>, <em>without the trailing
4745 slash</em>, then Apache httpd will redirect them to
4746 <code>http://www.example.com/splat/</code>. If you have
4747 authentication enabled, this will cause the user to have to
4748 authenticate twice (once for <code>www</code> and once again
4749 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">
4750 the FAQ on this subject for more information</a>). But if
4751 <code class="directive">UseCanonicalName</code> is set <code>Off</code>, then
4752 Apache httpd will redirect to <code>http://www/splat/</code>.</p>
4754 <p>There is a third option, <code>UseCanonicalName DNS</code>,
4755 which is intended for use with mass IP-based virtual hosting to
4756 support ancient clients that do not provide a
4757 <code>Host:</code> header. With this option, Apache httpd does a
4758 reverse DNS lookup on the server IP address that the client
4759 connected to in order to work out self-referential URLs.</p>
4761 <div class="warning"><h3>Warning</h3>
4762 <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>,
4763 they may be broken by this option. The client is essentially free
4764 to give whatever value they want as a hostname. But if the CGI is
4765 only using <code>SERVER_NAME</code> to construct self-referential URLs,
4766 then it should be just fine.</p>
4771 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
4772 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4773 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4776 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4777 <div class="directive-section"><h2><a name="UseCanonicalPhysicalPort" id="UseCanonicalPhysicalPort">UseCanonicalPhysicalPort</a> <a name="usecanonicalphysicalport" id="usecanonicalphysicalport">Directive</a></h2>
4778 <table class="directive">
4779 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own port</td></tr>
4780 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalPhysicalPort On|Off</code></td></tr>
4781 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalPhysicalPort Off</code></td></tr>
4782 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4783 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4784 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4786 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4787 URL -- that is, a URL that refers back to the same server. With
4788 <code>UseCanonicalPhysicalPort On</code>, Apache httpd will, when
4789 constructing the canonical port for the server to honor
4790 the <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> directive,
4791 provide the actual physical port number being used by this request
4792 as a potential port. With <code>UseCanonicalPhysicalPort Off</code>,
4793 Apache httpd will not ever use the actual physical port number, instead
4794 relying on all configured information to construct a valid port number.</p>
4796 <div class="note"><h3>Note</h3>
4797 <p>The ordering of the lookup when the physical port is used is as
4800 <dt><code>UseCanonicalName On</code></dt>
4803 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4804 <li>Physical port</li>
4805 <li>Default port</li>
4808 <dt><code>UseCanonicalName Off | DNS</code></dt>
4811 <li>Parsed port from <code>Host:</code> header</li>
4812 <li>Physical port</li>
4813 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4814 <li>Default port</li>
4819 <p>With <code>UseCanonicalPhysicalPort Off</code>, the
4820 physical ports are removed from the ordering.</p>
4826 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
4827 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4828 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4831 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4832 <div class="directive-section"><h2><a name="VirtualHost" id="VirtualHost"><VirtualHost></a> <a name="virtualhost" id="virtualhost">Directive</a></h2>
4833 <table class="directive">
4834 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only to a specific
4835 hostname or IP address</td></tr>
4836 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><VirtualHost
4837 <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
4838 ...> ... </VirtualHost></code></td></tr>
4839 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4840 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4841 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4843 <p><code class="directive"><VirtualHost></code> and
4844 <code></VirtualHost></code> are used to enclose a group of
4845 directives that will apply only to a particular virtual host. Any
4846 directive that is allowed in a virtual host context may be
4847 used. When the server receives a request for a document on a
4848 particular virtual host, it uses the configuration directives
4849 enclosed in the <code class="directive"><VirtualHost></code>
4850 section. <var>Addr</var> can be any of the following, optionally followed by
4851 a colon and a port number (or *):</p>
4854 <li>The IP address of the virtual host;</li>
4856 <li>A fully qualified domain name for the IP address of the
4857 virtual host (not recommended);</li>
4859 <li>The character <code>*</code>, which acts as a wildcard and matches
4860 any IP address.</li>
4862 <li>The string <code>_default_</code>, which is an alias for <code>*</code></li>
4866 <pre class="prettyprint lang-config"><VirtualHost 10.1.2.3:80>
4867 ServerAdmin webmaster@host.example.com
4868 DocumentRoot "/www/docs/host.example.com"
4869 ServerName host.example.com
4870 ErrorLog "logs/host.example.com-error_log"
4871 TransferLog "logs/host.example.com-access_log"
4872 </VirtualHost></pre>
4876 <p>IPv6 addresses must be specified in square brackets because
4877 the optional port number could not be determined otherwise. An
4878 IPv6 example is shown below:</p>
4880 <pre class="prettyprint lang-config"><VirtualHost [2001:db8::a00:20ff:fea7:ccea]:80>
4881 ServerAdmin webmaster@host.example.com
4882 DocumentRoot "/www/docs/host.example.com"
4883 ServerName host.example.com
4884 ErrorLog "logs/host.example.com-error_log"
4885 TransferLog "logs/host.example.com-access_log"
4886 </VirtualHost></pre>
4889 <p>Each Virtual Host must correspond to a different IP address,
4890 different port number, or a different host name for the server,
4891 in the former case the server machine must be configured to
4892 accept IP packets for multiple addresses. (If the machine does
4893 not have multiple network interfaces, then this can be
4894 accomplished with the <code>ifconfig alias</code> command -- if
4895 your OS supports it).</p>
4897 <div class="note"><h3>Note</h3>
4898 <p>The use of <code class="directive"><VirtualHost></code> does
4899 <strong>not</strong> affect what addresses Apache httpd listens on. You
4900 may need to ensure that Apache httpd is listening on the correct addresses
4901 using <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>.</p>
4904 <p>A <code class="directive"><a href="#servername">ServerName</a></code> should be
4905 specified inside each <code class="directive"><VirtualHost></code> block. If it is absent, the
4906 <code class="directive"><a href="#servername">ServerName</a></code> from the "main"
4907 server configuration will be inherited.</p>
4909 <p>When a request is received, the server first maps it to the best matching
4910 <code class="directive"><VirtualHost></code> based on the local
4911 IP address and port combination only. Non-wildcards have a higher
4912 precedence. If no match based on IP and port occurs at all, the
4913 "main" server configuration is used.</p>
4915 <p>If multiple virtual hosts contain the best matching IP address and port,
4916 the server selects from these virtual hosts the best match based on the
4917 requested hostname. If no matching name-based virtual host is found,
4918 then the first listed virtual host that matched the IP address will be
4919 used. As a consequence, the first listed virtual host for a given IP address
4920 and port combination is the default virtual host for that IP and port
4923 <div class="warning"><h3>Security</h3>
4924 <p>See the <a href="../misc/security_tips.html">security tips</a>
4925 document for details on why your security could be compromised if the
4926 directory where log files are stored is writable by anyone other
4927 than the user that starts the server.</p>
4932 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4933 <li><a href="../dns-caveats.html">Issues Regarding DNS and
4934 Apache HTTP Server</a></li>
4935 <li><a href="../bind.html">Setting
4936 which addresses and ports Apache HTTP Server uses</a></li>
4937 <li><a href="../sections.html">How <Directory>, <Location>
4938 and <Files> sections work</a> for an explanation of how these
4939 different sections are combined when a request is received</li>
4942 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4943 <div class="directive-section"><h2><a name="Warning" id="Warning">Warning</a> <a name="warning" id="warning">Directive</a></h2>
4944 <table class="directive">
4945 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Warn from configuration parsing with a custom message</td></tr>
4946 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Warning <var>message</var></code></td></tr>
4947 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4948 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4949 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4950 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.5 and later</td></tr>
4952 <p>If an issue can be detected from within the configuration, this
4953 directive can be used to generate a custom warning message. The
4954 configuration parsing is not halted. The typical use is to check
4955 whether some user define options are set, and warn if not.</p>
4957 <pre class="prettyprint lang-config"># Example
4958 # tell when ReverseProxy is not set
4959 <IfDefine !ReverseProxy>
4960 Warning "reverse proxy is not started, hope this is okay!"
4963 <IfDefine ReverseProxy>
4964 # define custom proxy configuration
4965 </IfDefine></pre>
4971 <div class="bottomlang">
4972 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
4973 <a href="../en/mod/core.html" title="English"> en </a> |
4974 <a href="../es/mod/core.html" hreflang="es" rel="alternate" title="Español"> es </a> |
4975 <a href="../fr/mod/core.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
4976 <a href="../ja/mod/core.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
4977 <a href="../tr/mod/core.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p>
4978 </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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