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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="#contentdigest">ContentDigest</a></li>
53 <li><img alt="" src="../images/down.gif" /> <a href="#defaultruntimedir">DefaultRuntimeDir</a></li>
54 <li><img alt="" src="../images/down.gif" /> <a href="#defaulttype">DefaultType</a></li>
55 <li><img alt="" src="../images/down.gif" /> <a href="#define">Define</a></li>
56 <li><img alt="" src="../images/down.gif" /> <a href="#directory"><Directory></a></li>
57 <li><img alt="" src="../images/down.gif" /> <a href="#directorymatch"><DirectoryMatch></a></li>
58 <li><img alt="" src="../images/down.gif" /> <a href="#documentroot">DocumentRoot</a></li>
59 <li><img alt="" src="../images/down.gif" /> <a href="#else"><Else></a></li>
60 <li><img alt="" src="../images/down.gif" /> <a href="#elseif"><ElseIf></a></li>
61 <li><img alt="" src="../images/down.gif" /> <a href="#enablemmap">EnableMMAP</a></li>
62 <li><img alt="" src="../images/down.gif" /> <a href="#enablesendfile">EnableSendfile</a></li>
63 <li><img alt="" src="../images/down.gif" /> <a href="#error">Error</a></li>
64 <li><img alt="" src="../images/down.gif" /> <a href="#errordocument">ErrorDocument</a></li>
65 <li><img alt="" src="../images/down.gif" /> <a href="#errorlog">ErrorLog</a></li>
66 <li><img alt="" src="../images/down.gif" /> <a href="#errorlogformat">ErrorLogFormat</a></li>
67 <li><img alt="" src="../images/down.gif" /> <a href="#extendedstatus">ExtendedStatus</a></li>
68 <li><img alt="" src="../images/down.gif" /> <a href="#fileetag">FileETag</a></li>
69 <li><img alt="" src="../images/down.gif" /> <a href="#files"><Files></a></li>
70 <li><img alt="" src="../images/down.gif" /> <a href="#filesmatch"><FilesMatch></a></li>
71 <li><img alt="" src="../images/down.gif" /> <a href="#forcetype">ForceType</a></li>
72 <li><img alt="" src="../images/down.gif" /> <a href="#gprofdir">GprofDir</a></li>
73 <li><img alt="" src="../images/down.gif" /> <a href="#hostnamelookups">HostnameLookups</a></li>
74 <li><img alt="" src="../images/down.gif" /> <a href="#if"><If></a></li>
75 <li><img alt="" src="../images/down.gif" /> <a href="#ifdefine"><IfDefine></a></li>
76 <li><img alt="" src="../images/down.gif" /> <a href="#ifmodule"><IfModule></a></li>
77 <li><img alt="" src="../images/down.gif" /> <a href="#include">Include</a></li>
78 <li><img alt="" src="../images/down.gif" /> <a href="#includeoptional">IncludeOptional</a></li>
79 <li><img alt="" src="../images/down.gif" /> <a href="#keepalive">KeepAlive</a></li>
80 <li><img alt="" src="../images/down.gif" /> <a href="#keepalivetimeout">KeepAliveTimeout</a></li>
81 <li><img alt="" src="../images/down.gif" /> <a href="#limit"><Limit></a></li>
82 <li><img alt="" src="../images/down.gif" /> <a href="#limitexcept"><LimitExcept></a></li>
83 <li><img alt="" src="../images/down.gif" /> <a href="#limitinternalrecursion">LimitInternalRecursion</a></li>
84 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestbody">LimitRequestBody</a></li>
85 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfields">LimitRequestFields</a></li>
86 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfieldsize">LimitRequestFieldSize</a></li>
87 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestline">LimitRequestLine</a></li>
88 <li><img alt="" src="../images/down.gif" /> <a href="#limitxmlrequestbody">LimitXMLRequestBody</a></li>
89 <li><img alt="" src="../images/down.gif" /> <a href="#location"><Location></a></li>
90 <li><img alt="" src="../images/down.gif" /> <a href="#locationmatch"><LocationMatch></a></li>
91 <li><img alt="" src="../images/down.gif" /> <a href="#loglevel">LogLevel</a></li>
92 <li><img alt="" src="../images/down.gif" /> <a href="#logleveloverride">LogLevelOverride</a></li>
93 <li><img alt="" src="../images/down.gif" /> <a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></li>
94 <li><img alt="" src="../images/down.gif" /> <a href="#maxrangeoverlaps">MaxRangeOverlaps</a></li>
95 <li><img alt="" src="../images/down.gif" /> <a href="#maxrangereversals">MaxRangeReversals</a></li>
96 <li><img alt="" src="../images/down.gif" /> <a href="#maxranges">MaxRanges</a></li>
97 <li><img alt="" src="../images/down.gif" /> <a href="#mergetrailers">MergeTrailers</a></li>
98 <li><img alt="" src="../images/down.gif" /> <a href="#mutex">Mutex</a></li>
99 <li><img alt="" src="../images/down.gif" /> <a href="#namevirtualhost">NameVirtualHost</a></li>
100 <li><img alt="" src="../images/down.gif" /> <a href="#options">Options</a></li>
101 <li><img alt="" src="../images/down.gif" /> <a href="#protocol">Protocol</a></li>
102 <li><img alt="" src="../images/down.gif" /> <a href="#protocols">Protocols</a></li>
103 <li><img alt="" src="../images/down.gif" /> <a href="#protocolshonororder">ProtocolsHonorOrder</a></li>
104 <li><img alt="" src="../images/down.gif" /> <a href="#qualifyredirecturl">QualifyRedirectURL</a></li>
105 <li><img alt="" src="../images/down.gif" /> <a href="#registerhttpmethod">RegisterHttpMethod</a></li>
106 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitcpu">RLimitCPU</a></li>
107 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitmem">RLimitMEM</a></li>
108 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitnproc">RLimitNPROC</a></li>
109 <li><img alt="" src="../images/down.gif" /> <a href="#scriptinterpretersource">ScriptInterpreterSource</a></li>
110 <li><img alt="" src="../images/down.gif" /> <a href="#seerequesttail">SeeRequestTail</a></li>
111 <li><img alt="" src="../images/down.gif" /> <a href="#serveradmin">ServerAdmin</a></li>
112 <li><img alt="" src="../images/down.gif" /> <a href="#serveralias">ServerAlias</a></li>
113 <li><img alt="" src="../images/down.gif" /> <a href="#servername">ServerName</a></li>
114 <li><img alt="" src="../images/down.gif" /> <a href="#serverpath">ServerPath</a></li>
115 <li><img alt="" src="../images/down.gif" /> <a href="#serverroot">ServerRoot</a></li>
116 <li><img alt="" src="../images/down.gif" /> <a href="#serversignature">ServerSignature</a></li>
117 <li><img alt="" src="../images/down.gif" /> <a href="#servertokens">ServerTokens</a></li>
118 <li><img alt="" src="../images/down.gif" /> <a href="#sethandler">SetHandler</a></li>
119 <li><img alt="" src="../images/down.gif" /> <a href="#setinputfilter">SetInputFilter</a></li>
120 <li><img alt="" src="../images/down.gif" /> <a href="#setoutputfilter">SetOutputFilter</a></li>
121 <li><img alt="" src="../images/down.gif" /> <a href="#timeout">TimeOut</a></li>
122 <li><img alt="" src="../images/down.gif" /> <a href="#traceenable">TraceEnable</a></li>
123 <li><img alt="" src="../images/down.gif" /> <a href="#undefine">UnDefine</a></li>
124 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalname">UseCanonicalName</a></li>
125 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></li>
126 <li><img alt="" src="../images/down.gif" /> <a href="#virtualhost"><VirtualHost></a></li>
127 <li><img alt="" src="../images/down.gif" /> <a href="#warning">Warning</a></li>
129 <ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div>
131 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
132 <div class="directive-section"><h2><a name="AcceptFilter" id="AcceptFilter">AcceptFilter</a> <a name="acceptfilter" id="acceptfilter">Directive</a></h2>
133 <table class="directive">
134 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures optimizations for a Protocol's Listener Sockets</td></tr>
135 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptFilter <var>protocol</var> <var>accept_filter</var></code></td></tr>
136 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
137 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
138 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
140 <p>This directive enables operating system specific optimizations for a
141 listening socket by the <code class="directive">Protocol</code> type.
142 The basic premise is for the kernel to not send a socket to the server
143 process until either data is received or an entire HTTP Request is buffered.
144 Only <a href="http://www.freebsd.org/cgi/man.cgi?query=accept_filter&sektion=9">
145 FreeBSD's Accept Filters</a>, Linux's more primitive
146 <code>TCP_DEFER_ACCEPT</code>, and Windows' optimized AcceptEx()
147 are currently supported.</p>
149 <p>Using <code>none</code> for an argument will disable any accept filters
150 for that protocol. This is useful for protocols that require a server
151 send data first, such as <code>ftp:</code> or <code>nntp</code>:</p>
152 <pre class="prettyprint lang-config">AcceptFilter nntp none</pre>
155 <p>The default protocol names are <code>https</code> for port 443
156 and <code>http</code> for all other ports. To specify that another
157 protocol is being used with a listening port, add the <var>protocol</var>
158 argument to the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>
161 <p>The default values on FreeBSD are:</p>
162 <pre class="prettyprint lang-config">AcceptFilter http httpready
163 AcceptFilter https dataready</pre>
166 <p>The <code>httpready</code> accept filter buffers entire HTTP requests at
167 the kernel level. Once an entire request is received, the kernel then
168 sends it to the server. See the
169 <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_http&sektion=9">
170 accf_http(9)</a> man page for more details. Since HTTPS requests are
171 encrypted, only the <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_data&sektion=9">
172 accf_data(9)</a> filter is used.</p>
174 <p>The default values on Linux are:</p>
175 <pre class="prettyprint lang-config">AcceptFilter http data
176 AcceptFilter https data</pre>
179 <p>Linux's <code>TCP_DEFER_ACCEPT</code> does not support buffering http
180 requests. Any value besides <code>none</code> will enable
181 <code>TCP_DEFER_ACCEPT</code> on that listener. For more details
183 <a href="http://homepages.cwi.nl/~aeb/linux/man2html/man7/tcp.7.html">
184 tcp(7)</a> man page.</p>
186 <p>The default values on Windows are:</p>
187 <pre class="prettyprint lang-config">AcceptFilter http data
188 AcceptFilter https data</pre>
191 <p>Window's mpm_winnt interprets the AcceptFilter to toggle the AcceptEx()
192 API, and does not support http protocol buffering. There are two values
193 which utilize the Windows AcceptEx() API and will recycle network
194 sockets between connections. <code>data</code> waits until data has
195 been transmitted as documented above, and the initial data buffer and
196 network endpoint addresses are all retrieved from the single AcceptEx()
197 invocation. <code>connect</code> will use the AcceptEx() API, also
198 retrieve the network endpoint addresses, but like <code>none</code>
199 the <code>connect</code> option does not wait for the initial data
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
211 <li><code class="directive"><a href="#protocol">Protocol</a></code></li>
214 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
215 <div class="directive-section"><h2><a name="AcceptPathInfo" id="AcceptPathInfo">AcceptPathInfo</a> <a name="acceptpathinfo" id="acceptpathinfo">Directive</a></h2>
216 <table class="directive">
217 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Resources accept trailing pathname information</td></tr>
218 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptPathInfo On|Off|Default</code></td></tr>
219 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AcceptPathInfo Default</code></td></tr>
220 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
221 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
222 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
223 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
226 <p>This directive controls whether requests that contain trailing
227 pathname information that follows an actual filename (or
228 non-existent file in an existing directory) will be accepted or
229 rejected. The trailing pathname information can be made
230 available to scripts in the <code>PATH_INFO</code> environment
233 <p>For example, assume the location <code>/test/</code> points to
234 a directory that contains only the single file
235 <code>here.html</code>. Then requests for
236 <code>/test/here.html/more</code> and
237 <code>/test/nothere.html/more</code> both collect
238 <code>/more</code> as <code>PATH_INFO</code>.</p>
240 <p>The three possible arguments for the
241 <code class="directive">AcceptPathInfo</code> directive are:</p>
243 <dt><code>Off</code></dt><dd>A request will only be accepted if it
244 maps to a literal path that exists. Therefore a request with
245 trailing pathname information after the true filename such as
246 <code>/test/here.html/more</code> in the above example will return
247 a 404 NOT FOUND error.</dd>
249 <dt><code>On</code></dt><dd>A request will be accepted if a
250 leading path component maps to a file that exists. The above
251 example <code>/test/here.html/more</code> will be accepted if
252 <code>/test/here.html</code> maps to a valid file.</dd>
254 <dt><code>Default</code></dt><dd>The treatment of requests with
255 trailing pathname information is determined by the <a href="../handler.html">handler</a> responsible for the request.
256 The core handler for normal files defaults to rejecting
257 <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
258 <code>PATH_INFO</code> by default.</dd>
261 <p>The primary purpose of the <code>AcceptPathInfo</code>
262 directive is to allow you to override the handler's choice of
263 accepting or rejecting <code>PATH_INFO</code>. This override is required,
264 for example, when you use a <a href="../filter.html">filter</a>, such
265 as <a href="mod_include.html">INCLUDES</a>, to generate content
266 based on <code>PATH_INFO</code>. The core handler would usually reject
267 the request, so you can use the following configuration to enable
270 <pre class="prettyprint lang-config"><Files "mypaths.shtml">
272 SetOutputFilter INCLUDES
279 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
280 <div class="directive-section"><h2><a name="AccessFileName" id="AccessFileName">AccessFileName</a> <a name="accessfilename" id="accessfilename">Directive</a></h2>
281 <table class="directive">
282 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Name of the distributed configuration file</td></tr>
283 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AccessFileName <var>filename</var> [<var>filename</var>] ...</code></td></tr>
284 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AccessFileName .htaccess</code></td></tr>
285 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
286 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
287 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
289 <p>While processing a request, the server looks for
290 the first existing configuration file from this list of names in
291 every directory of the path to the document, if distributed
292 configuration files are <a href="#allowoverride">enabled for that
293 directory</a>. For example:</p>
295 <pre class="prettyprint lang-config">AccessFileName .acl</pre>
298 <p>Before returning the document
299 <code>/usr/local/web/index.html</code>, the server will read
300 <code>/.acl</code>, <code>/usr/.acl</code>,
301 <code>/usr/local/.acl</code> and <code>/usr/local/web/.acl</code>
302 for directives unless they have been disabled with:</p>
304 <pre class="prettyprint lang-config"><Directory "/">
306 </Directory></pre>
311 <li><code class="directive"><a href="#allowoverride">AllowOverride</a></code></li>
312 <li><a href="../configuring.html">Configuration Files</a></li>
313 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
316 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
317 <div class="directive-section"><h2><a name="AddDefaultCharset" id="AddDefaultCharset">AddDefaultCharset</a> <a name="adddefaultcharset" id="adddefaultcharset">Directive</a></h2>
318 <table class="directive">
319 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Default charset parameter to be added when a response
320 content-type is <code>text/plain</code> or <code>text/html</code></td></tr>
321 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AddDefaultCharset On|Off|<var>charset</var></code></td></tr>
322 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AddDefaultCharset Off</code></td></tr>
323 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
324 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
325 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
326 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
328 <p>This directive specifies a default value for the media type
329 charset parameter (the name of a character encoding) to be added
330 to a response if and only if the response's content-type is either
331 <code>text/plain</code> or <code>text/html</code>. This should override
332 any charset specified in the body of the response via a <code>META</code>
333 element, though the exact behavior is often dependent on the user's client
334 configuration. A setting of <code>AddDefaultCharset Off</code>
335 disables this functionality. <code>AddDefaultCharset On</code> enables
336 a default charset of <code>iso-8859-1</code>. Any other value is assumed
337 to be the <var>charset</var> to be used, which should be one of the
338 <a href="http://www.iana.org/assignments/character-sets">IANA registered
339 charset values</a> for use in Internet media types (MIME types).
342 <pre class="prettyprint lang-config">AddDefaultCharset utf-8</pre>
345 <p><code class="directive">AddDefaultCharset</code> should only be used when all
346 of the text resources to which it applies are known to be in that
347 character encoding and it is too inconvenient to label their charset
348 individually. One such example is to add the charset parameter
349 to resources containing generated content, such as legacy CGI
350 scripts, that might be vulnerable to cross-site scripting attacks
351 due to user-provided data being included in the output. Note, however,
352 that a better solution is to just fix (or delete) those scripts, since
353 setting a default charset does not protect users that have enabled
354 the "auto-detect character encoding" feature on their browser.</p>
358 <li><code class="directive"><a href="../mod/mod_mime.html#addcharset">AddCharset</a></code></li>
361 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
362 <div class="directive-section"><h2><a name="AllowEncodedSlashes" id="AllowEncodedSlashes">AllowEncodedSlashes</a> <a name="allowencodedslashes" id="allowencodedslashes">Directive</a></h2>
363 <table class="directive">
364 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines whether encoded path separators in URLs are allowed to
365 be passed through</td></tr>
366 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowEncodedSlashes On|Off|NoDecode</code></td></tr>
367 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowEncodedSlashes Off</code></td></tr>
368 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
369 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
370 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
371 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>
372 NoDecode option available in 2.3.12 and later.</td></tr>
374 <p>The <code class="directive">AllowEncodedSlashes</code> directive allows URLs
375 which contain encoded path separators (<code>%2F</code> for <code>/</code>
376 and additionally <code>%5C</code> for <code>\</code> on accordant systems)
377 to be used in the path info.</p>
379 <p>With the default value, <code>Off</code>, such URLs are refused
380 with a 404 (Not found) error.</p>
382 <p>With the value <code>On</code>, such URLs are accepted, and encoded
383 slashes are decoded like all other encoded characters.</p>
385 <p>With the value <code>NoDecode</code>, such URLs are accepted, but
386 encoded slashes are not decoded but left in their encoded state.</p>
388 <p>Turning <code class="directive">AllowEncodedSlashes</code> <code>On</code> is
389 mostly useful when used in conjunction with <code>PATH_INFO</code>.</p>
391 <div class="note"><h3>Note</h3>
392 <p>If encoded slashes are needed in path info, use of <code>NoDecode</code> is
393 strongly recommended as a security measure. Allowing slashes
394 to be decoded could potentially allow unsafe paths.</p>
399 <li><code class="directive"><a href="#acceptpathinfo">AcceptPathInfo</a></code></li>
402 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
403 <div class="directive-section"><h2><a name="AllowOverride" id="AllowOverride">AllowOverride</a> <a name="allowoverride" id="allowoverride">Directive</a></h2>
404 <table class="directive">
405 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Types of directives that are allowed in
406 <code>.htaccess</code> files</td></tr>
407 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowOverride All|None|<var>directive-type</var>
408 [<var>directive-type</var>] ...</code></td></tr>
409 <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>
410 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
411 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
412 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
414 <p>When the server finds an <code>.htaccess</code> file (as
415 specified by <code class="directive"><a href="#accessfilename">AccessFileName</a></code>),
416 it needs to know which directives declared in that file can override
417 earlier configuration directives.</p>
419 <div class="note"><h3>Only available in <Directory> sections</h3>
420 <code class="directive">AllowOverride</code> is valid only in
421 <code class="directive"><a href="#directory"><Directory></a></code>
422 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
423 <code class="directive"><a href="#files"><Files></a></code> sections.
426 <p>When this directive is set to <code>None</code> and <code class="directive"><a href="#allowoverridelist">AllowOverrideList</a></code> is set to
427 <code>None</code>, <a href="#accessfilename">.htaccess</a> files are
428 completely ignored. In this case, the server will not even attempt
429 to read <code>.htaccess</code> files in the filesystem.</p>
431 <p>When this directive is set to <code>All</code>, then any
432 directive which has the .htaccess <a href="directive-dict.html#Context">Context</a> is allowed in
433 <code>.htaccess</code> files.</p>
435 <p>The <var>directive-type</var> can be one of the following
436 groupings of directives.</p>
443 Allow use of the authorization directives (<code class="directive"><a href="../mod/mod_authz_dbm.html#authdbmgroupfile">AuthDBMGroupFile</a></code>,
444 <code class="directive"><a href="../mod/mod_authn_dbm.html#authdbmuserfile">AuthDBMUserFile</a></code>,
445 <code class="directive"><a href="../mod/mod_authz_groupfile.html#authgroupfile">AuthGroupFile</a></code>,
446 <code class="directive"><a href="../mod/mod_authn_core.html#authname">AuthName</a></code>,
447 <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>
452 Allow use of the directives controlling document types
453 (<code class="directive"><a href="#errordocument">ErrorDocument</a></code>,
454 <code class="directive"><a href="#forcetype">ForceType</a></code>,
455 <code class="directive"><a href="../mod/mod_negotiation.html#languagepriority">LanguagePriority</a></code>,
456 <code class="directive"><a href="#sethandler">SetHandler</a></code>,
457 <code class="directive"><a href="#setinputfilter">SetInputFilter</a></code>,
458 <code class="directive"><a href="#setoutputfilter">SetOutputFilter</a></code>, and
459 <code class="module"><a href="../mod/mod_mime.html">mod_mime</a></code> Add* and Remove* directives),
460 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>),
461 <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>),
462 <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
463 <code class="directive"><a href="../mod/mod_actions.html#action">Action</a></code> from
464 <code class="module"><a href="../mod/mod_actions.html">mod_actions</a></code>.
470 Allow use of the directives controlling directory indexing
471 (<code class="directive"><a href="../mod/mod_autoindex.html#adddescription">AddDescription</a></code>,
472 <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>,
473 <code class="directive"><a href="../mod/mod_autoindex.html#addiconbytype">AddIconByType</a></code>,
474 <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>,
480 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>
485 <dt>Nonfatal=[Override|Unknown|All]</dt>
488 Allow use of AllowOverride option to treat syntax errors in
489 .htaccess as nonfatal. Instead of causing an Internal Server
490 Error, disallowed or unrecognised directives will be ignored
491 and a warning logged:
493 <li><strong>Nonfatal=Override</strong> treats directives
494 forbidden by AllowOverride as nonfatal.</li>
495 <li><strong>Nonfatal=Unknown</strong> treats unknown directives
496 as nonfatal. This covers typos and directives implemented
497 by a module that's not present.</li>
498 <li><strong>Nonfatal=All</strong> treats both the above as nonfatal.</li>
500 <p>Note that a syntax error in a valid directive will still cause
501 an internal server error.</p>
502 <div class="warning"><h3>Security</h3>
503 Nonfatal errors may have security implications for .htaccess users.
504 For example, if AllowOverride disallows AuthConfig, users'
505 configuration designed to restrict access to a site will be disabled.
509 <dt>Options[=<var>Option</var>,...]</dt>
512 Allow use of the directives controlling specific directory
513 features (<code class="directive"><a href="#options">Options</a></code> and
514 <code class="directive"><a href="../mod/mod_include.html#xbithack">XBitHack</a></code>).
515 An equal sign may be given followed by a comma-separated list, without
516 spaces, of options that may be set using the <code class="directive"><a href="#options">Options</a></code> command.
518 <div class="note"><h3>Implicit disabling of Options</h3>
519 <p>Even though the list of options that may be used in .htaccess files
520 can be limited with this directive, as long as any <code class="directive"><a href="#options">Options</a></code> directive is allowed any
521 other inherited option can be disabled by using the non-relative
522 syntax. In other words, this mechanism cannot force a specific option
523 to remain <em>set</em> while allowing any others to be set.
526 <div class="example"><p><code>
527 AllowOverride Options=Indexes,MultiViews
534 <pre class="prettyprint lang-config">AllowOverride AuthConfig Indexes</pre>
537 <p>In the example above, all directives that are neither in the group
538 <code>AuthConfig</code> nor <code>Indexes</code> cause an internal
541 <div class="note"><p>For security and performance reasons, do not set
542 <code>AllowOverride</code> to anything other than <code>None</code>
543 in your <code><Directory "/"></code> block. Instead, find (or
544 create) the <code><Directory></code> block that refers to the
545 directory where you're actually planning to place a
546 <code>.htaccess</code> file.</p>
551 <li><code class="directive"><a href="#accessfilename">AccessFileName</a></code></li>
552 <li><code class="directive"><a href="#allowoverridelist">AllowOverrideList</a></code></li>
553 <li><a href="../configuring.html">Configuration Files</a></li>
554 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
557 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
558 <div class="directive-section"><h2><a name="AllowOverrideList" id="AllowOverrideList">AllowOverrideList</a> <a name="allowoverridelist" id="allowoverridelist">Directive</a></h2>
559 <table class="directive">
560 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Individual directives that are allowed in
561 <code>.htaccess</code> files</td></tr>
562 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowOverrideList None|<var>directive</var>
563 [<var>directive-type</var>] ...</code></td></tr>
564 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowOverrideList None</code></td></tr>
565 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
566 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
567 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
569 <p>When the server finds an <code>.htaccess</code> file (as
570 specified by <code class="directive"><a href="#accessfilename">AccessFileName</a></code>),
571 it needs to know which directives declared in that file can override
572 earlier configuration directives.</p>
574 <div class="note"><h3>Only available in <Directory> sections</h3>
575 <code class="directive">AllowOverrideList</code> is valid only in
576 <code class="directive"><a href="#directory"><Directory></a></code>
577 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
578 <code class="directive"><a href="#files"><Files></a></code> sections.
581 <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>,
582 then <a href="#accessfilename">.htaccess</a> files are completely
583 ignored. In this case, the server will not even attempt to read
584 <code>.htaccess</code> files in the filesystem.</p>
588 <pre class="prettyprint lang-config">AllowOverride None
589 AllowOverrideList Redirect RedirectMatch</pre>
592 <p>In the example above, only the <code>Redirect</code> and
593 <code>RedirectMatch</code> directives are allowed. All others will
594 cause an internal server error.</p>
598 <pre class="prettyprint lang-config">AllowOverride AuthConfig
599 AllowOverrideList CookieTracking CookieName</pre>
602 <p>In the example above, <code class="directive"><a href="#allowoverride">AllowOverride
603 </a></code> grants permission to the <code>AuthConfig</code>
604 directive grouping and <code class="directive">AllowOverrideList</code> grants
605 permission to only two directives from the <code>FileInfo</code> directive
606 grouping. All others will cause an internal server error.</p>
610 <li><code class="directive"><a href="#accessfilename">AccessFileName</a></code></li>
611 <li><code class="directive"><a href="#allowoverride">AllowOverride</a></code></li>
612 <li><a href="../configuring.html">Configuration Files</a></li>
613 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
616 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
617 <div class="directive-section"><h2><a name="AsyncFilter" id="AsyncFilter">AsyncFilter</a> <a name="asyncfilter" id="asyncfilter">Directive</a></h2>
618 <table class="directive">
619 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Set the minimum filter type eligible for asynchronous handling</td></tr>
620 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AsyncFilter request|connection|network</code></td></tr>
621 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AsyncFilter request</code></td></tr>
622 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
623 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
624 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
625 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Only available from Apache 2.5.0 and later.</td></tr>
627 <p>This directive controls the minimum filter levels that are eligible
628 for asynchronous handling. This may be necessary to support legacy external
629 filters that did not handle meta buckets correctly.</p>
631 <p>If set to "network", asynchronous handling will be limited to the network
632 filter only. If set to "connection", all connection and network filters
633 will be eligible for asynchronous handling, including <code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code>.
634 If set to "request", all filters will be eligible for asynchronous handling.</p>
637 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
638 <div class="directive-section"><h2><a name="CGIMapExtension" id="CGIMapExtension">CGIMapExtension</a> <a name="cgimapextension" id="cgimapextension">Directive</a></h2>
639 <table class="directive">
640 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
642 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CGIMapExtension <var>cgi-path</var> <var>.extension</var></code></td></tr>
643 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
644 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
645 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
646 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
647 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>NetWare only</td></tr>
649 <p>This directive is used to control how Apache httpd finds the
650 interpreter used to run CGI scripts. For example, setting
651 <code>CGIMapExtension sys:\foo.nlm .foo</code> will
652 cause all CGI script files with a <code>.foo</code> extension to
653 be passed to the FOO interpreter.</p>
656 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
657 <div class="directive-section"><h2><a name="CGIPassAuth" id="CGIPassAuth">CGIPassAuth</a> <a name="cgipassauth" id="cgipassauth">Directive</a></h2>
658 <table class="directive">
659 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables passing HTTP authorization headers to scripts as CGI
661 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CGIPassAuth On|Off</code></td></tr>
662 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>CGIPassAuth Off</code></td></tr>
663 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
664 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig</td></tr>
665 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
666 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
667 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.4.13 and later</td></tr>
669 <p><code class="directive">CGIPassAuth</code> allows scripts access to HTTP
670 authorization headers such as <code>Authorization</code>, which is
671 required for scripts that implement HTTP Basic authentication.
672 Normally these HTTP headers are hidden from scripts. This is to disallow
673 scripts from seeing user ids and passwords used to access the server when
674 HTTP Basic authentication is enabled in the web server. This directive
675 should be used when scripts are allowed to implement HTTP Basic
678 <p>This directive can be used instead of the compile-time setting
679 <code>SECURITY_HOLE_PASS_AUTHORIZATION</code> which has been available
680 in previous versions of Apache HTTP Server.</p>
682 <p>The setting is respected by any modules which use
683 <code>ap_add_common_vars()</code>, such as <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>,
684 <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>,
685 <code class="module"><a href="../mod/mod_proxy_scgi.html">mod_proxy_scgi</a></code>, and so on. Notably, it affects
686 modules which don't handle the request in the usual sense but
687 still use this API; examples of this are <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
688 and <code class="module"><a href="../mod/mod_ext_filter.html">mod_ext_filter</a></code>. Third-party modules that don't
689 use <code>ap_add_common_vars()</code> may choose to respect the setting
693 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
694 <div class="directive-section"><h2><a name="ContentDigest" id="ContentDigest">ContentDigest</a> <a name="contentdigest" id="contentdigest">Directive</a></h2>
695 <table class="directive">
696 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables the generation of <code>Content-MD5</code> HTTP Response
698 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ContentDigest On|Off</code></td></tr>
699 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ContentDigest Off</code></td></tr>
700 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
701 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
702 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
703 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
705 <p>This directive enables the generation of
706 <code>Content-MD5</code> headers as defined in RFC1864
707 respectively RFC2616.</p>
709 <p>MD5 is an algorithm for computing a "message digest"
710 (sometimes called "fingerprint") of arbitrary-length data, with
711 a high degree of confidence that any alterations in the data
712 will be reflected in alterations in the message digest.</p>
714 <p>The <code>Content-MD5</code> header provides an end-to-end
715 message integrity check (MIC) of the entity-body. A proxy or
716 client may check this header for detecting accidental
717 modification of the entity-body in transit. Example header:</p>
719 <div class="example"><p><code>
720 Content-MD5: AuLb7Dp1rqtRtxz2m9kRpA==
723 <p>Note that this can cause performance problems on your server
724 since the message digest is computed on every request (the
725 values are not cached).</p>
727 <p><code>Content-MD5</code> is only sent for documents served
728 by the <code class="module"><a href="../mod/core.html">core</a></code>, and not by any module. For example,
729 SSI documents, output from CGI scripts, and byte range responses
730 do not have this header.</p>
733 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
734 <div class="directive-section"><h2><a name="DefaultRuntimeDir" id="DefaultRuntimeDir">DefaultRuntimeDir</a> <a name="defaultruntimedir" id="defaultruntimedir">Directive</a></h2>
735 <table class="directive">
736 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server run-time files</td></tr>
737 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultRuntimeDir <var>directory-path</var></code></td></tr>
738 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultRuntimeDir DEFAULT_REL_RUNTIMEDIR (logs/)</code></td></tr>
739 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
740 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
741 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
742 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.4.2 and later</td></tr>
744 <p>The <code class="directive">DefaultRuntimeDir</code> directive sets the
745 directory in which the server will create various run-time files
746 (shared memory, locks, etc.). If set as a relative path, the full path
747 will be relative to <code class="directive">ServerRoot</code>.</p>
749 <p><strong>Example</strong></p>
750 <pre class="prettyprint lang-config">DefaultRuntimeDir scratch/</pre>
753 <p>The default location of <code class="directive">DefaultRuntimeDir</code> may be
754 modified by changing the <code>DEFAULT_REL_RUNTIMEDIR</code> #define
757 <p>Note: <code class="directive">ServerRoot</code> should be specified before this
758 directive is used. Otherwise, the default value of <code class="directive">ServerRoot</code>
759 would be used to set the base directory.</p>
764 <li><a href="../misc/security_tips.html#serverroot">the
765 security tips</a> for information on how to properly set
766 permissions on the <code class="directive">ServerRoot</code></li>
769 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
770 <div class="directive-section"><h2><a name="DefaultType" id="DefaultType">DefaultType</a> <a name="defaulttype" id="defaulttype">Directive</a></h2>
771 <table class="directive">
772 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>This directive has no effect other than to emit warnings
773 if the value is not <code>none</code>. In prior versions, DefaultType
774 would specify a default media type to assign to response content for
775 which no other media type configuration could be found.
777 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultType <var>media-type|none</var></code></td></tr>
778 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultType none</code></td></tr>
779 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
780 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
781 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
782 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
783 <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.
786 <p>This directive has been disabled. For backwards compatibility
787 of configuration files, it may be specified with the value
788 <code>none</code>, meaning no default media type. For example:</p>
790 <pre class="prettyprint lang-config">DefaultType None</pre>
793 <p><code>DefaultType None</code> is only available in
794 httpd-2.2.7 and later.</p>
796 <p>Use the mime.types configuration file and the
797 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code> to configure media
798 type assignments via file extensions, or the
799 <code class="directive"><a href="#forcetype">ForceType</a></code> directive to configure
800 the media type for specific resources. Otherwise, the server will
801 send the response without a Content-Type header field and the
802 recipient may attempt to guess the media type.</p>
805 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
806 <div class="directive-section"><h2><a name="Define" id="Define">Define</a> <a name="define" id="define">Directive</a></h2>
807 <table class="directive">
808 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Define a variable</td></tr>
809 <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>
810 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
811 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
812 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
814 <p>In its one parameter form, <code class="directive">Define</code> is equivalent
815 to passing the <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>. It
816 can be used to toggle the use of
817 <code class="directive"><a href="#ifdefine"><IfDefine></a></code> sections
818 without needing to alter <code>-D</code> arguments in any startup
821 <p>In addition to that, if the second parameter is given, a config variable
822 is set to this value. The variable can be used in the configuration using
823 the <code>${VAR}</code> syntax. The variable is always globally defined
824 and not limited to the scope of the surrounding config section.</p>
826 <pre class="prettyprint lang-config"><IfDefine TEST>
827 Define servername test.example.com
829 <IfDefine !TEST>
830 Define servername www.example.com
834 DocumentRoot "/var/www/${servername}/htdocs"</pre>
837 <p>Variable names may not contain colon ":" characters, to avoid clashes
838 with <code class="directive"><a href="../mod/mod_rewrite.html#rewritemap">RewriteMap</a></code>'s syntax.</p>
840 <p>While this directive is supported in virtual host context,
841 the changes it makes are visible to any later configuration
842 directives, beyond any enclosing virtual host</p>
845 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
846 <div class="directive-section"><h2><a name="Directory" id="Directory"><Directory></a> <a name="directory" id="directory">Directive</a></h2>
847 <table class="directive">
848 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose a group of directives that apply only to the
849 named file-system directory, sub-directories, and their contents.</td></tr>
850 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Directory <var>directory-path</var>>
851 ... </Directory></code></td></tr>
852 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
853 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
854 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
856 <p><code class="directive"><Directory></code> and
857 <code></Directory></code> are used to enclose a group of
858 directives that will apply only to the named directory,
859 sub-directories of that directory, and the files within the respective
860 directories. Any directive that is allowed
861 in a directory context may be used. <var>Directory-path</var> is
862 either the full path to a directory, or a wild-card string using
863 Unix shell-style matching. In a wild-card string, <code>?</code> matches
864 any single character, and <code>*</code> matches any sequences of
865 characters. You may also use <code>[]</code> character ranges. None
866 of the wildcards match a `/' character, so <code><Directory
867 "/*/public_html"></code> will not match
868 <code>/home/user/public_html</code>, but <code><Directory
869 "/home/*/public_html"></code> will match. Example:</p>
871 <pre class="prettyprint lang-config"><Directory "/usr/local/httpd/htdocs">
872 Options Indexes FollowSymLinks
873 </Directory></pre>
876 <p>Directory paths <em>may</em> be quoted, if you like, however, it
877 <em>must</em> be quoted if the path contains spaces. This is because a
878 space would otherwise indicate the end of an argument.</p>
881 <p>Be careful with the <var>directory-path</var> arguments:
882 They have to literally match the filesystem path which Apache httpd uses
883 to access the files. Directives applied to a particular
884 <code><Directory></code> will not apply to files accessed from
885 that same directory via a different path, such as via different symbolic
889 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular
890 expressions</a> can also be used, with the addition of the
891 <code>~</code> character. For example:</p>
893 <pre class="prettyprint lang-config"><Directory ~ "^/www/[0-9]{3}">
895 </Directory></pre>
898 <p>would match directories in <code>/www/</code> that consisted of
901 <p>If multiple (non-regular expression) <code class="directive"><Directory></code> sections
902 match the directory (or one of its parents) containing a document,
903 then the directives are applied in the order of shortest match
904 first, interspersed with the directives from the <a href="#accessfilename">.htaccess</a> files. For example,
907 <pre class="prettyprint lang-config"><Directory "/">
911 <Directory "/home">
912 AllowOverride FileInfo
913 </Directory></pre>
916 <p>for access to the document <code>/home/web/dir/doc.html</code>
920 <li>Apply directive <code>AllowOverride None</code>
921 (disabling <code>.htaccess</code> files).</li>
923 <li>Apply directive <code>AllowOverride FileInfo</code> (for
924 directory <code>/home</code>).</li>
926 <li>Apply any <code>FileInfo</code> directives in
927 <code>/home/.htaccess</code>, <code>/home/web/.htaccess</code> and
928 <code>/home/web/dir/.htaccess</code> in that order.</li>
931 <p>Regular expressions are not considered until after all of the
932 normal sections have been applied. Then all of the regular
933 expressions are tested in the order they appeared in the
934 configuration file. For example, with</p>
936 <pre class="prettyprint lang-config"><Directory ~ "abc$">
937 # ... directives here ...
938 </Directory></pre>
941 <p>the regular expression section won't be considered until after
942 all normal <code class="directive"><Directory></code>s and
943 <code>.htaccess</code> files have been applied. Then the regular
944 expression will match on <code>/home/abc/public_html/abc</code> and
945 the corresponding <code class="directive"><Directory></code> will
948 <p><strong>Note that the default access for
949 <code><Directory "/"></code> is to permit all access.
950 This means that Apache httpd will serve any file mapped from an URL. It is
951 recommended that you change this with a block such
954 <pre class="prettyprint lang-config"><Directory "/">
956 </Directory></pre>
959 <p><strong>and then override this for directories you
960 <em>want</em> accessible. See the <a href="../misc/security_tips.html">Security Tips</a> page for more
961 details.</strong></p>
963 <p>The directory sections occur in the <code>httpd.conf</code> file.
964 <code class="directive"><Directory></code> directives
965 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>
969 <li><a href="../sections.html">How <Directory>,
970 <Location> and <Files> sections work</a> for an
971 explanation of how these different sections are combined when a
972 request is received</li>
975 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
976 <div class="directive-section"><h2><a name="DirectoryMatch" id="DirectoryMatch"><DirectoryMatch></a> <a name="directorymatch" id="directorymatch">Directive</a></h2>
977 <table class="directive">
978 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose directives that apply to
979 the contents of file-system directories matching a regular expression.</td></tr>
980 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><DirectoryMatch <var>regex</var>>
981 ... </DirectoryMatch></code></td></tr>
982 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
983 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
984 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
986 <p><code class="directive"><DirectoryMatch></code> and
987 <code></DirectoryMatch></code> are used to enclose a group
988 of directives which will apply only to the named directory (and the files within),
989 the same as <code class="directive"><a href="#directory"><Directory></a></code>.
990 However, it takes as an argument a
991 <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>. For example:</p>
993 <pre class="prettyprint lang-config"><DirectoryMatch "^/www/(.+/)?[0-9]{3}/">
995 </DirectoryMatch></pre>
998 <p>matches directories in <code>/www/</code> (or any subdirectory thereof)
999 that consist of three numbers.</p>
1001 <div class="note"><h3>Compatability</h3>
1002 Prior to 2.3.9, this directive implicitly applied to sub-directories
1003 (like <code class="directive"><a href="#directory"><Directory></a></code>) and
1004 could not match the end of line symbol ($). In 2.3.9 and later,
1005 only directories that match the expression are affected by the enclosed
1009 <div class="note"><h3>Trailing Slash</h3>
1010 This directive applies to requests for directories that may or may
1011 not end in a trailing slash, so expressions that are anchored to the
1012 end of line ($) must be written with care.
1015 <p>From 2.4.8 onwards, named groups and backreferences are captured and
1016 written to the environment with the corresponding name prefixed with
1017 "MATCH_" and in upper case. This allows elements of paths to be referenced
1018 from within <a href="../expr.html">expressions</a> and modules like
1019 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
1020 (unnamed) backreferences are ignored. Use named groups instead.</p>
1022 <pre class="prettyprint lang-config"><DirectoryMatch "^/var/www/combined/(?<sitename>[^/]+)">
1023 Require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
1024 </DirectoryMatch></pre>
1029 <li><code class="directive"><a href="#directory"><Directory></a></code> for
1030 a description of how regular expressions are mixed in with normal
1031 <code class="directive"><Directory></code>s</li>
1032 <li><a href="../sections.html">How <Directory>, <Location> and
1033 <Files> sections work</a> for an explanation of how these different
1034 sections are combined when a request is received</li>
1037 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1038 <div class="directive-section"><h2><a name="DocumentRoot" id="DocumentRoot">DocumentRoot</a> <a name="documentroot" id="documentroot">Directive</a></h2>
1039 <table class="directive">
1040 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory that forms the main document tree visible
1041 from the web</td></tr>
1042 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DocumentRoot <var>directory-path</var></code></td></tr>
1043 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DocumentRoot /usr/local/apache/htdocs</code></td></tr>
1044 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1045 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1046 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1048 <p>This directive sets the directory from which <code class="program"><a href="../programs/httpd.html">httpd</a></code>
1049 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
1050 path from the requested URL to the document root to make the
1051 path to the document. Example:</p>
1053 <pre class="prettyprint lang-config">DocumentRoot "/usr/web"</pre>
1056 <p>then an access to
1057 <code>http://my.example.com/index.html</code> refers to
1058 <code>/usr/web/index.html</code>. If the <var>directory-path</var> is
1059 not absolute then it is assumed to be relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1061 <p>The <code class="directive">DocumentRoot</code> should be specified without
1062 a trailing slash.</p>
1066 <li><a href="../urlmapping.html#documentroot">Mapping URLs to Filesystem
1070 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1071 <div class="directive-section"><h2><a name="Else" id="Else"><Else></a> <a name="else" id="else">Directive</a></h2>
1072 <table class="directive">
1073 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if the condition of a
1074 previous <code class="directive"><a href="#if"><If></a></code> or
1075 <code class="directive"><a href="#elseif"><ElseIf></a></code> section is not
1076 satisfied by a request at runtime</td></tr>
1077 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Else> ... </Else></code></td></tr>
1078 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1079 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1080 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1081 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1083 <p>The <code class="directive"><Else></code> applies the enclosed
1084 directives if and only if the most recent
1085 <code class="directive"><If></code> or
1086 <code class="directive"><ElseIf></code> section
1087 in the same scope has not been applied.
1088 For example: In </p>
1090 <pre class="prettyprint lang-config"><If "-z req('Host')">
1098 <p> The <code class="directive"><If></code> would match HTTP/1.0
1099 requests without a <var>Host:</var> header and the
1100 <code class="directive"><Else></code> would match requests
1101 with a <var>Host:</var> header.</p>
1106 <li><code class="directive"><a href="#if"><If></a></code></li>
1107 <li><code class="directive"><a href="#elseif"><ElseIf></a></code></li>
1108 <li><a href="../sections.html">How <Directory>, <Location>,
1109 <Files> sections work</a> for an explanation of how these
1110 different sections are combined when a request is received.
1111 <code class="directive"><If></code>,
1112 <code class="directive"><ElseIf></code>, and
1113 <code class="directive"><Else></code> are applied last.</li>
1116 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1117 <div class="directive-section"><h2><a name="ElseIf" id="ElseIf"><ElseIf></a> <a name="elseif" id="elseif">Directive</a></h2>
1118 <table class="directive">
1119 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is satisfied
1120 by a request at runtime while the condition of a previous
1121 <code class="directive"><a href="#if"><If></a></code> or
1122 <code class="directive"><ElseIf></code> section is not
1124 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><ElseIf <var>expression</var>> ... </ElseIf></code></td></tr>
1125 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1126 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1127 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1128 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1130 <p>The <code class="directive"><ElseIf></code> applies the enclosed
1131 directives if and only if both the given condition evaluates to true and
1132 the most recent <code class="directive"><If></code> or
1133 <code class="directive"><ElseIf></code> section in the same scope has
1134 not been applied. For example: In </p>
1136 <pre class="prettyprint lang-config"><If "-R '10.1.0.0/16'">
1139 <ElseIf "-R '10.0.0.0/8'">
1147 <p>The <code class="directive"><ElseIf></code> would match if
1148 the remote address of a request belongs to the subnet 10.0.0.0/8 but
1149 not to the subnet 10.1.0.0/16.</p>
1154 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
1155 for a complete reference and more examples.</li>
1156 <li><code class="directive"><a href="#if"><If></a></code></li>
1157 <li><code class="directive"><a href="#else"><Else></a></code></li>
1158 <li><a href="../sections.html">How <Directory>, <Location>,
1159 <Files> sections work</a> for an explanation of how these
1160 different sections are combined when a request is received.
1161 <code class="directive"><If></code>,
1162 <code class="directive"><ElseIf></code>, and
1163 <code class="directive"><Else></code> are applied last.</li>
1166 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1167 <div class="directive-section"><h2><a name="EnableMMAP" id="EnableMMAP">EnableMMAP</a> <a name="enablemmap" id="enablemmap">Directive</a></h2>
1168 <table class="directive">
1169 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use memory-mapping to read files during delivery</td></tr>
1170 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableMMAP On|Off</code></td></tr>
1171 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableMMAP On</code></td></tr>
1172 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1173 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1174 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1175 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1177 <p>This directive controls whether the <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use
1178 memory-mapping if it needs to read the contents of a file during
1179 delivery. By default, when the handling of a request requires
1180 access to the data within a file -- for example, when delivering a
1181 server-parsed file using <code class="module"><a href="../mod/mod_include.html">mod_include</a></code> -- Apache httpd
1182 memory-maps the file if the OS supports it.</p>
1184 <p>This memory-mapping sometimes yields a performance improvement.
1185 But in some environments, it is better to disable the memory-mapping
1186 to prevent operational problems:</p>
1189 <li>On some multiprocessor systems, memory-mapping can reduce the
1190 performance of the <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</li>
1191 <li>Deleting or truncating a file while <code class="program"><a href="../programs/httpd.html">httpd</a></code>
1192 has it memory-mapped can cause <code class="program"><a href="../programs/httpd.html">httpd</a></code> to
1193 crash with a segmentation fault.
1197 <p>For server configurations that are vulnerable to these problems,
1198 you should disable memory-mapping of delivered files by specifying:</p>
1200 <pre class="prettyprint lang-config">EnableMMAP Off</pre>
1203 <p>For NFS mounted files, this feature may be disabled explicitly for
1204 the offending files by specifying:</p>
1206 <pre class="prettyprint lang-config"><Directory "/path-to-nfs-files">
1208 </Directory></pre>
1212 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1213 <div class="directive-section"><h2><a name="EnableSendfile" id="EnableSendfile">EnableSendfile</a> <a name="enablesendfile" id="enablesendfile">Directive</a></h2>
1214 <table class="directive">
1215 <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>
1216 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableSendfile On|Off</code></td></tr>
1217 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableSendfile Off</code></td></tr>
1218 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1219 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1220 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1221 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1222 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Default changed to Off in
1223 version 2.3.9.</td></tr>
1225 <p>This directive controls whether <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use the
1226 sendfile support from the kernel to transmit file contents to the client.
1227 By default, when the handling of a request requires no access
1228 to the data within a file -- for example, when delivering a
1229 static file -- Apache httpd uses sendfile to deliver the file contents
1230 without ever reading the file if the OS supports it.</p>
1232 <p>This sendfile mechanism avoids separate read and send operations,
1233 and buffer allocations. But on some platforms or within some
1234 filesystems, it is better to disable this feature to avoid
1235 operational problems:</p>
1238 <li>Some platforms may have broken sendfile support that the build
1239 system did not detect, especially if the binaries were built on
1240 another box and moved to such a machine with broken sendfile
1242 <li>On Linux the use of sendfile triggers TCP-checksum
1243 offloading bugs on certain networking cards when using IPv6.</li>
1244 <li>On Linux on Itanium, <code>sendfile</code> may be unable to handle
1245 files over 2GB in size.</li>
1246 <li>With a network-mounted <code class="directive"><a href="#documentroot">DocumentRoot</a></code> (e.g., NFS, SMB, CIFS, FUSE),
1247 the kernel may be unable to serve the network file through
1251 <p>For server configurations that are not vulnerable to these problems,
1252 you may enable this feature by specifying:</p>
1254 <pre class="prettyprint lang-config">EnableSendfile On</pre>
1257 <p>For network mounted files, this feature may be disabled explicitly
1258 for the offending files by specifying:</p>
1260 <pre class="prettyprint lang-config"><Directory "/path-to-nfs-files">
1262 </Directory></pre>
1264 <p>Please note that the per-directory and .htaccess configuration
1265 of <code class="directive">EnableSendfile</code> is not supported by
1266 <code class="module"><a href="../mod/mod_cache_disk.html">mod_cache_disk</a></code>.
1267 Only global definition of <code class="directive">EnableSendfile</code>
1268 is taken into account by the module.
1272 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1273 <div class="directive-section"><h2><a name="Error" id="Error">Error</a> <a name="error" id="error">Directive</a></h2>
1274 <table class="directive">
1275 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Abort configuration parsing with a custom error message</td></tr>
1276 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Error <var>message</var></code></td></tr>
1277 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1278 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1279 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1280 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.3.9 and later</td></tr>
1282 <p>If an error can be detected within the configuration, this
1283 directive can be used to generate a custom error message, and halt
1284 configuration parsing. The typical use is for reporting required
1285 modules which are missing from the configuration.</p>
1287 <pre class="prettyprint lang-config"># Example
1288 # ensure that mod_include is loaded
1289 <IfModule !include_module>
1290 Error "mod_include is required by mod_foo. Load it with LoadModule."
1293 # ensure that exactly one of SSL,NOSSL is defined
1294 <IfDefine SSL>
1295 <IfDefine NOSSL>
1296 Error "Both SSL and NOSSL are defined. Define only one of them."
1299 <IfDefine !SSL>
1300 <IfDefine !NOSSL>
1301 Error "Either SSL or NOSSL must be defined."
1303 </IfDefine></pre>
1308 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1309 <div class="directive-section"><h2><a name="ErrorDocument" id="ErrorDocument">ErrorDocument</a> <a name="errordocument" id="errordocument">Directive</a></h2>
1310 <table class="directive">
1311 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>What the server will return to the client
1312 in case of an error</td></tr>
1313 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ErrorDocument <var>error-code</var> <var>document</var></code></td></tr>
1314 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1315 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1316 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1317 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1319 <p>In the event of a problem or error, Apache httpd can be configured
1320 to do one of four things,</p>
1323 <li>output a simple hardcoded error message</li>
1325 <li>output a customized message</li>
1327 <li>internally redirect to a local <var>URL-path</var> to handle the
1330 <li>redirect to an external <var>URL</var> to handle the
1334 <p>The first option is the default, while options 2-4 are
1335 configured using the <code class="directive">ErrorDocument</code>
1336 directive, which is followed by the HTTP response code and a URL
1337 or a message. Apache httpd will sometimes offer additional information
1338 regarding the problem/error.</p>
1340 <p>From 2.4.13, <a href="../expr.html">expression syntax</a> can be
1341 used inside the directive to produce dynamic strings and URLs.</p>
1343 <p>URLs can begin with a slash (/) for local web-paths (relative
1344 to the <code class="directive"><a href="#documentroot">DocumentRoot</a></code>), or be a
1345 full URL which the client can resolve. Alternatively, a message
1346 can be provided to be displayed by the browser. Note that deciding
1347 whether the parameter is an URL, a path or a message is performed
1348 before any expression is parsed. Examples:</p>
1350 <pre class="prettyprint lang-config">ErrorDocument 500 http://foo.example.com/cgi-bin/tester
1351 ErrorDocument 404 /cgi-bin/bad_urls.pl
1352 ErrorDocument 401 /subscription_info.html
1353 ErrorDocument 403 "Sorry can't allow you access today"
1354 ErrorDocument 403 Forbidden!
1355 ErrorDocument 403 /cgi-bin/forbidden.pl?referrer=%{escape:%{HTTP_REFERER}}</pre>
1358 <p>Additionally, the special value <code>default</code> can be used
1359 to specify Apache httpd's simple hardcoded message. While not required
1360 under normal circumstances, <code>default</code> will restore
1361 Apache httpd's simple hardcoded message for configurations that would
1362 otherwise inherit an existing <code class="directive">ErrorDocument</code>.</p>
1364 <pre class="prettyprint lang-config">ErrorDocument 404 /cgi-bin/bad_urls.pl
1366 <Directory "/web/docs">
1367 ErrorDocument 404 default
1368 </Directory></pre>
1371 <p>Note that when you specify an <code class="directive">ErrorDocument</code>
1372 that points to a remote URL (ie. anything with a method such as
1373 <code>http</code> in front of it), Apache HTTP Server will send a redirect to the
1374 client to tell it where to find the document, even if the
1375 document ends up being on the same server. This has several
1376 implications, the most important being that the client will not
1377 receive the original error status code, but instead will
1378 receive a redirect status code. This in turn can confuse web
1379 robots and other clients which try to determine if a URL is
1380 valid using the status code. In addition, if you use a remote
1381 URL in an <code>ErrorDocument 401</code>, the client will not
1382 know to prompt the user for a password since it will not
1383 receive the 401 status code. Therefore, <strong>if you use an
1384 <code>ErrorDocument 401</code> directive, then it must refer to a local
1385 document.</strong></p>
1387 <p>Microsoft Internet Explorer (MSIE) will by default ignore
1388 server-generated error messages when they are "too small" and substitute
1389 its own "friendly" error messages. The size threshold varies depending on
1390 the type of error, but in general, if you make your error document
1391 greater than 512 bytes, then MSIE will show the server-generated
1392 error rather than masking it. More information is available in
1393 Microsoft Knowledge Base article <a href="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q294807">Q294807</a>.</p>
1395 <p>Although most error messages can be overridden, there are certain
1396 circumstances where the internal messages are used regardless of the
1397 setting of <code class="directive"><a href="#errordocument">ErrorDocument</a></code>. In
1398 particular, if a malformed request is detected, normal request processing
1399 will be immediately halted and the internal error message returned.
1400 This is necessary to guard against security problems caused by
1403 <p>If you are using mod_proxy, you may wish to enable
1404 <code class="directive"><a href="../mod/mod_proxy.html#proxyerroroverride">ProxyErrorOverride</a></code> so that you can provide
1405 custom error messages on behalf of your Origin servers. If you don't enable ProxyErrorOverride,
1406 Apache httpd will not generate custom error documents for proxied content.</p>
1410 <li><a href="../custom-error.html">documentation of
1411 customizable responses</a></li>
1414 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1415 <div class="directive-section"><h2><a name="ErrorLog" id="ErrorLog">ErrorLog</a> <a name="errorlog" id="errorlog">Directive</a></h2>
1416 <table class="directive">
1417 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Location where the server will log errors</td></tr>
1418 <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>
1419 <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>
1420 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1421 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1422 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1424 <p>The <code class="directive">ErrorLog</code> directive sets the name of
1425 the file to which the server will log any errors it encounters. If
1426 the <var>file-path</var> is not absolute then it is assumed to be
1427 relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1429 <pre class="prettyprint lang-config">ErrorLog "/var/log/httpd/error_log"</pre>
1432 <p>If the <var>file-path</var>
1433 begins with a pipe character "<code>|</code>" then it is assumed to be a
1434 command to spawn to handle the error log.</p>
1436 <pre class="prettyprint lang-config">ErrorLog "|/usr/local/bin/httpd_errors"</pre>
1439 <p>See the notes on <a href="../logs.html#piped">piped logs</a> for
1440 more information.</p>
1442 <p>Using <code>syslog</code> instead of a filename enables logging
1443 via syslogd(8) if the system supports it and if <code class="module"><a href="../mod/mod_syslog.html">mod_syslog</a></code>
1444 is loaded. The default is to use syslog facility <code>local7</code>,
1445 but you can override this by using the <code>syslog:<var>facility</var></code>
1446 syntax where <var>facility</var> can be one of the names usually documented in
1447 syslog(1). The facility is effectively global, and if it is changed
1448 in individual virtual hosts, the final facility specified affects the
1451 <pre class="prettyprint lang-config">ErrorLog syslog:user</pre>
1454 <p>Additional modules can provide their own ErrorLog providers. The syntax
1455 is similar to the <code>syslog</code> example above.</p>
1457 <p>SECURITY: See the <a href="../misc/security_tips.html#serverroot">security tips</a>
1458 document for details on why your security could be compromised
1459 if the directory where log files are stored is writable by
1460 anyone other than the user that starts the server.</p>
1461 <div class="warning"><h3>Note</h3>
1462 <p>When entering a file path on non-Unix platforms, care should be taken
1463 to make sure that only forward slashes are used even though the platform
1464 may allow the use of back slashes. In general it is a good idea to always
1465 use forward slashes throughout the configuration files.</p>
1470 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1471 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1474 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1475 <div class="directive-section"><h2><a name="ErrorLogFormat" id="ErrorLogFormat">ErrorLogFormat</a> <a name="errorlogformat" id="errorlogformat">Directive</a></h2>
1476 <table class="directive">
1477 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Format specification for error log entries</td></tr>
1478 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code> ErrorLogFormat [connection|request] <var>format</var></code></td></tr>
1479 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1480 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1481 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1483 <p><code class="directive">ErrorLogFormat</code> allows to specify what
1484 supplementary information is logged in the error log in addition to the
1485 actual log message.</p>
1487 <pre class="prettyprint lang-config">#Simple example
1488 ErrorLogFormat "[%t] [%l] [pid %P] %F: %E: [client %a] %M"</pre>
1491 <p>Specifying <code>connection</code> or <code>request</code> as first
1492 parameter allows to specify additional formats, causing additional
1493 information to be logged when the first message is logged for a specific
1494 connection or request, respectively. This additional information is only
1495 logged once per connection/request. If a connection or request is processed
1496 without causing any log message, the additional information is not logged
1499 <p>It can happen that some format string items do not produce output. For
1500 example, the Referer header is only present if the log message is
1501 associated to a request and the log message happens at a time when the
1502 Referer header has already been read from the client. If no output is
1503 produced, the default behavior is to delete everything from the preceding
1504 space character to the next space character. This means the log line is
1505 implicitly divided into fields on non-whitespace to whitespace transitions.
1506 If a format string item does not produce output, the whole field is
1507 omitted. For example, if the remote address <code>%a</code> in the log
1508 format <code>[%t] [%l] [%a] %M </code> is not available, the surrounding
1509 brackets are not logged either. Space characters can be escaped with a
1510 backslash to prevent them from delimiting a field. The combination '% '
1511 (percent space) is a zero-width field delimiter that does not produce any
1514 <p>The above behavior can be changed by adding modifiers to the format
1515 string item. A <code>-</code> (minus) modifier causes a minus to be logged if the
1516 respective item does not produce any output. In once-per-connection/request
1517 formats, it is also possible to use the <code>+</code> (plus) modifier. If an
1518 item with the plus modifier does not produce any output, the whole line is
1521 <p>A number as modifier can be used to assign a log severity level to a
1522 format item. The item will only be logged if the severity of the log
1523 message is not higher than the specified log severity level. The number can
1524 range from 1 (alert) over 4 (warn) and 7 (debug) to 15 (trace8).</p>
1526 <p>For example, here's what would happen if you added modifiers to
1527 the <code>%{Referer}i</code> token, which logs the
1528 <code>Referer</code> request header.</p>
1530 <table class="bordered"><tr class="header"><th>Modified Token</th><th>Meaning</th></tr>
1532 <td><code>%-{Referer}i</code></td>
1533 <td>Logs a <code>-</code> if <code>Referer</code> is not set.</td>
1536 <td><code>%+{Referer}i</code></td>
1537 <td>Omits the entire line if <code>Referer</code> is not set.</td>
1540 <td><code>%4{Referer}i</code></td>
1541 <td>Logs the <code>Referer</code> only if the log message severity
1542 is higher than 4.</td>
1546 <p>Some format string items accept additional parameters in braces.</p>
1548 <table class="bordered"><tr class="header"><th>Format String</th> <th>Description</th></tr>
1549 <tr><td><code>%%</code></td>
1550 <td>The percent sign</td></tr>
1551 <tr class="odd"><td><code>%a</code></td>
1552 <td>Client IP address and port of the request</td></tr>
1553 <tr><td><code>%{c}a</code></td>
1554 <td>Underlying peer IP address and port of the connection (see the
1555 <code class="module"><a href="../mod/mod_remoteip.html">mod_remoteip</a></code> module)</td></tr>
1556 <tr class="odd"><td><code>%A</code></td>
1557 <td>Local IP-address and port</td></tr>
1558 <tr><td><code>%{<em>name</em>}e</code></td>
1559 <td>Request environment variable <em>name</em></td></tr>
1560 <tr class="odd"><td><code>%E</code></td>
1561 <td>APR/OS error status code and string</td></tr>
1562 <tr><td><code>%F</code></td>
1563 <td>Source file name and line number of the log call</td></tr>
1564 <tr class="odd"><td><code>%{<em>name</em>}i</code></td>
1565 <td>Request header <em>name</em></td></tr>
1566 <tr><td><code>%k</code></td>
1567 <td>Number of keep-alive requests on this connection</td></tr>
1568 <tr class="odd"><td><code>%l</code></td>
1569 <td>Loglevel of the message</td></tr>
1570 <tr><td><code>%L</code></td>
1571 <td>Log ID of the request</td></tr>
1572 <tr class="odd"><td><code>%{c}L</code></td>
1573 <td>Log ID of the connection</td></tr>
1574 <tr><td><code>%{C}L</code></td>
1575 <td>Log ID of the connection if used in connection scope, empty otherwise</td></tr>
1576 <tr class="odd"><td><code>%m</code></td>
1577 <td>Name of the module logging the message</td></tr>
1578 <tr><td><code>%M</code></td>
1579 <td>The actual log message</td></tr>
1580 <tr class="odd"><td><code>%{<em>name</em>}n</code></td>
1581 <td>Request note <em>name</em></td></tr>
1582 <tr><td><code>%P</code></td>
1583 <td>Process ID of current process</td></tr>
1584 <tr class="odd"><td><code>%T</code></td>
1585 <td>Thread ID of current thread</td></tr>
1586 <tr><td><code>%{g}T</code></td>
1587 <td>System unique thread ID of current thread (the same ID as
1588 displayed by e.g. <code>top</code>; currently Linux only)</td></tr>
1589 <tr class="odd"><td><code>%t</code></td>
1590 <td>The current time</td></tr>
1591 <tr><td><code>%{u}t</code></td>
1592 <td>The current time including micro-seconds</td></tr>
1593 <tr class="odd"><td><code>%{cu}t</code></td>
1594 <td>The current time in compact ISO 8601 format, including
1595 micro-seconds</td></tr>
1596 <tr><td><code>%v</code></td>
1597 <td>The canonical <code class="directive"><a href="#servername">ServerName</a></code>
1598 of the current server.</td></tr>
1599 <tr class="odd"><td><code>%V</code></td>
1600 <td>The server name of the server serving the request according to the
1601 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code>
1603 <tr><td><code>\ </code> (backslash space)</td>
1604 <td>Non-field delimiting space</td></tr>
1605 <tr class="odd"><td><code>% </code> (percent space)</td>
1606 <td>Field delimiter (no output)</td></tr>
1609 <p>The log ID format <code>%L</code> produces a unique id for a connection
1610 or request. This can be used to correlate which log lines belong to the
1611 same connection or request, which request happens on which connection.
1612 A <code>%L</code> format string is also available in
1613 <code class="module"><a href="../mod/mod_log_config.html">mod_log_config</a></code> to allow to correlate access log entries
1614 with error log lines. If <code class="module"><a href="../mod/mod_unique_id.html">mod_unique_id</a></code> is loaded, its
1615 unique id will be used as log ID for requests.</p>
1617 <pre class="prettyprint lang-config">#Example (default format for threaded MPMs)
1618 ErrorLogFormat "[%{u}t] [%-m:%l] [pid %P:tid %T] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"</pre>
1621 <p>This would result in error messages such as:</p>
1623 <div class="example"><p><code>
1624 [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
1627 <p>Notice that, as discussed above, some fields are omitted
1628 entirely because they are not defined.</p>
1630 <pre class="prettyprint lang-config">#Example (similar to the 2.2.x format)
1631 ErrorLogFormat "[%t] [%l] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"</pre>
1634 <pre class="prettyprint lang-config">#Advanced example with request/connection log IDs
1635 ErrorLogFormat "[%{uc}t] [%-m:%-l] [R:%L] [C:%{C}L] %7F: %E: %M"
1636 ErrorLogFormat request "[%{uc}t] [R:%L] Request %k on C:%{c}L pid:%P tid:%T"
1637 ErrorLogFormat request "[%{uc}t] [R:%L] UA:'%+{User-Agent}i'"
1638 ErrorLogFormat request "[%{uc}t] [R:%L] Referer:'%+{Referer}i'"
1639 ErrorLogFormat connection "[%{uc}t] [C:%{c}L] local\ %a remote\ %A"</pre>
1645 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
1646 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1647 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1650 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1651 <div class="directive-section"><h2><a name="ExtendedStatus" id="ExtendedStatus">ExtendedStatus</a> <a name="extendedstatus" id="extendedstatus">Directive</a></h2>
1652 <table class="directive">
1653 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Keep track of extended status information for each
1655 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ExtendedStatus On|Off</code></td></tr>
1656 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ExtendedStatus Off[*]</code></td></tr>
1657 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
1658 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1659 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1661 <p>This option tracks additional data per worker about the
1662 currently executing request and creates a utilization summary.
1663 You can see these variables during runtime by configuring
1664 <code class="module"><a href="../mod/mod_status.html">mod_status</a></code>. Note that other modules may
1665 rely on this scoreboard.</p>
1667 <p>This setting applies to the entire server and cannot be
1668 enabled or disabled on a virtualhost-by-virtualhost basis.
1669 The collection of extended status information can slow down
1670 the server. Also note that this setting cannot be changed
1671 during a graceful restart.</p>
1674 <p>Note that loading <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> will change
1675 the default behavior to ExtendedStatus On, while other
1676 third party modules may do the same. Such modules rely on
1677 collecting detailed information about the state of all workers.
1678 The default is changed by <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> beginning
1679 with version 2.3.6. The previous default was always Off.</p>
1684 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1685 <div class="directive-section"><h2><a name="FileETag" id="FileETag">FileETag</a> <a name="fileetag" id="fileetag">Directive</a></h2>
1686 <table class="directive">
1687 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>File attributes used to create the ETag
1688 HTTP response header for static files</td></tr>
1689 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>FileETag <var>component</var> ...</code></td></tr>
1690 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>FileETag MTime Size</code></td></tr>
1691 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1692 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1693 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1694 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1695 <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
1699 The <code class="directive">FileETag</code> directive configures the file
1700 attributes that are used to create the <code>ETag</code> (entity
1701 tag) response header field when the document is based on a static file.
1702 (The <code>ETag</code> value is used in cache management to save
1703 network bandwidth.) The
1704 <code class="directive">FileETag</code> directive allows you to choose
1705 which of these -- if any -- should be used. The recognized keywords are:
1709 <dt><strong>INode</strong></dt>
1710 <dd>The file's i-node number will be included in the calculation</dd>
1711 <dt><strong>MTime</strong></dt>
1712 <dd>The date and time the file was last modified will be included</dd>
1713 <dt><strong>Size</strong></dt>
1714 <dd>The number of bytes in the file will be included</dd>
1715 <dt><strong>All</strong></dt>
1716 <dd>All available fields will be used. This is equivalent to:
1717 <pre class="prettyprint lang-config">FileETag INode MTime Size</pre>
1719 <dt><strong>None</strong></dt>
1720 <dd>If a document is file-based, no <code>ETag</code> field will be
1721 included in the response</dd>
1724 <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
1725 keywords may be prefixed with either <code>+</code> or <code>-</code>,
1726 which allow changes to be made to the default setting inherited
1727 from a broader scope. Any keyword appearing without such a prefix
1728 immediately and completely cancels the inherited setting.</p>
1730 <p>If a directory's configuration includes
1731 <code>FileETag INode MTime Size</code>, and a
1732 subdirectory's includes <code>FileETag -INode</code>,
1733 the setting for that subdirectory (which will be inherited by
1734 any sub-subdirectories that don't override it) will be equivalent to
1735 <code>FileETag MTime Size</code>.</p>
1736 <div class="warning"><h3>Warning</h3>
1737 Do not change the default for directories or locations that have WebDAV
1738 enabled and use <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> as a storage provider.
1739 <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> uses <code>MTime Size</code>
1740 as a fixed format for <code>ETag</code> comparisons on conditional requests.
1741 These conditional requests will break if the <code>ETag</code> format is
1742 changed via <code class="directive">FileETag</code>.
1744 <div class="note"><h3>Server Side Includes</h3>
1745 An ETag is not generated for responses parsed by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
1746 since the response entity can change without a change of the INode, MTime, or Size
1747 of the static file with embedded SSI directives.
1752 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1753 <div class="directive-section"><h2><a name="Files" id="Files"><Files></a> <a name="files" id="files">Directive</a></h2>
1754 <table class="directive">
1755 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to matched
1757 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Files <var>filename</var>> ... </Files></code></td></tr>
1758 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1759 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1760 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1761 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1763 <p>The <code class="directive"><Files></code> directive
1764 limits the scope of the enclosed directives by filename. It is comparable
1765 to the <code class="directive"><a href="#directory"><Directory></a></code>
1766 and <code class="directive"><a href="#location"><Location></a></code>
1767 directives. It should be matched with a <code></Files></code>
1768 directive. The directives given within this section will be applied to
1769 any object with a basename (last component of filename) matching the
1770 specified filename. <code class="directive"><Files></code>
1771 sections are processed in the order they appear in the
1772 configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
1773 <code>.htaccess</code> files are read, but before <code class="directive"><a href="#location"><Location></a></code> sections. Note
1774 that <code class="directive"><Files></code> can be nested
1775 inside <code class="directive"><a href="#directory"><Directory></a></code> sections to restrict the
1776 portion of the filesystem they apply to.</p>
1778 <p>The <var>filename</var> argument should include a filename, or
1779 a wild-card string, where <code>?</code> matches any single character,
1780 and <code>*</code> matches any sequences of characters.</p>
1781 <pre class="prettyprint lang-config"><Files "cat.html">
1782 # Insert stuff that applies to cat.html here
1785 <Files "?at.*">
1786 # This would apply to cat.html, bat.html, hat.php and so on.
1787 </Files></pre>
1789 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
1790 can also be used, with the addition of the
1791 <code>~</code> character. For example:</p>
1793 <pre class="prettyprint lang-config"><Files ~ "\.(gif|jpe?g|png)$">
1795 </Files></pre>
1798 <p>would match most common Internet graphics formats. <code class="directive"><a href="#filesmatch"><FilesMatch></a></code> is preferred,
1801 <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
1802 <code>.htaccess</code> files. This allows users to control access to
1803 their own files, at a file-by-file level.</p>
1808 <li><a href="../sections.html">How <Directory>, <Location>
1809 and <Files> sections work</a> for an explanation of how these
1810 different sections are combined when a request is received</li>
1813 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1814 <div class="directive-section"><h2><a name="FilesMatch" id="FilesMatch"><FilesMatch></a> <a name="filesmatch" id="filesmatch">Directive</a></h2>
1815 <table class="directive">
1816 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to regular-expression matched
1818 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><FilesMatch <var>regex</var>> ... </FilesMatch></code></td></tr>
1819 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1820 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1821 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1822 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1824 <p>The <code class="directive"><FilesMatch></code> directive
1825 limits the scope of the enclosed directives by filename, just as the
1826 <code class="directive"><a href="#files"><Files></a></code> directive
1827 does. However, it accepts a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular
1828 expression</a>. For example:</p>
1830 <pre class="prettyprint lang-config"><FilesMatch ".+\.(gif|jpe?g|png)$">
1832 </FilesMatch></pre>
1835 <p>would match most common Internet graphics formats.</p>
1837 <div class="note">The <code>.+</code> at the start of the regex ensures that
1838 files named <code>.png</code>, or <code>.gif</code>, for example,
1839 are not matched.</div>
1841 <p>From 2.4.8 onwards, named groups and backreferences are captured and
1842 written to the environment with the corresponding name prefixed with
1843 "MATCH_" and in upper case. This allows elements of files to be referenced
1844 from within <a href="../expr.html">expressions</a> and modules like
1845 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
1846 (unnamed) backreferences are ignored. Use named groups instead.</p>
1848 <pre class="prettyprint lang-config"><FilesMatch "^(?<sitename>[^/]+)">
1849 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
1850 </FilesMatch></pre>
1855 <li><a href="../sections.html">How <Directory>, <Location>
1856 and <Files> sections work</a> for an explanation of how these
1857 different sections are combined when a request is received</li>
1860 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1861 <div class="directive-section"><h2><a name="ForceType" id="ForceType">ForceType</a> <a name="forcetype" id="forcetype">Directive</a></h2>
1862 <table class="directive">
1863 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be served with the specified
1864 media type in the HTTP Content-Type header field</td></tr>
1865 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ForceType <var>media-type</var>|None</code></td></tr>
1866 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
1867 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1868 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1869 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1871 <p>When placed into an <code>.htaccess</code> file or a
1872 <code class="directive"><a href="#directory"><Directory></a></code>, or
1873 <code class="directive"><a href="#location"><Location></a></code> or
1874 <code class="directive"><a href="#files"><Files></a></code>
1875 section, this directive forces all matching files to be served
1876 with the content type identification given by
1877 <var>media-type</var>. For example, if you had a directory full of
1878 GIF files, but did not want to label them all with <code>.gif</code>,
1879 you might want to use:</p>
1881 <pre class="prettyprint lang-config">ForceType image/gif</pre>
1884 <p>Note that this directive overrides other indirect media type
1885 associations defined in mime.types or via the
1886 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code>.</p>
1888 <p>You can also override more general
1889 <code class="directive">ForceType</code> settings
1890 by using the value of <code>None</code>:</p>
1892 <pre class="prettyprint lang-config"># force all files to be image/gif:
1893 <Location "/images">
1897 # but normal mime-type associations here:
1898 <Location "/images/mixed">
1900 </Location></pre>
1903 <p>This directive primarily overrides the content types generated for
1904 static files served out of the filesystem. For resources other than
1905 static files, where the generator of the response typically specifies
1906 a Content-Type, this directive has no effect.</p>
1909 <div class="note"><h3>Note</h3>
1910 <p>If no handler is explicitly set for a request, the specified content
1911 type will also be used as the handler name. </p>
1913 <p>When explicit directives such as
1914 <code class="directive"><a href="#sethandler">SetHandler</a></code> or
1915 <code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code> do not apply
1916 to the current request, the internal handler name normally set by those
1917 directives is instead set to the content type specified by this directive.
1920 This is a historical behavior that some third-party modules
1921 (such as mod_php) may look for a "synthetic" content type used only to
1922 signal the module to take responsibility for the matching request.
1925 <p>Configurations that rely on such "synthetic" types should be avoided.
1926 Additionally, configurations that restrict access to
1927 <code class="directive"><a href="#sethandler">SetHandler</a></code> or
1928 <code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code> should
1929 restrict access to this directive as well.</p>
1934 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1935 <div class="directive-section"><h2><a name="GprofDir" id="GprofDir">GprofDir</a> <a name="gprofdir" id="gprofdir">Directive</a></h2>
1936 <table class="directive">
1937 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory to write gmon.out profiling data to. </td></tr>
1938 <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>
1939 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1940 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1941 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1943 <p>When the server has been compiled with gprof profiling support,
1944 <code class="directive">GprofDir</code> causes <code>gmon.out</code> files to
1945 be written to the specified directory when the process exits. If the
1946 argument ends with a percent symbol ('%'), subdirectories are created
1947 for each process id.</p>
1949 <p>This directive currently only works with the <code class="module"><a href="../mod/prefork.html">prefork</a></code>
1953 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1954 <div class="directive-section"><h2><a name="HostnameLookups" id="HostnameLookups">HostnameLookups</a> <a name="hostnamelookups" id="hostnamelookups">Directive</a></h2>
1955 <table class="directive">
1956 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables DNS lookups on client IP addresses</td></tr>
1957 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>HostnameLookups On|Off|Double</code></td></tr>
1958 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>HostnameLookups Off</code></td></tr>
1959 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1960 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1961 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1963 <p>This directive enables DNS lookups so that host names can be
1964 logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
1965 The value <code>Double</code> refers to doing double-reverse
1966 DNS lookup. That is, after a reverse lookup is performed, a forward
1967 lookup is then performed on that result. At least one of the IP
1968 addresses in the forward lookup must match the original
1969 address. (In "tcpwrappers" terminology this is called
1970 <code>PARANOID</code>.)</p>
1972 <p>Regardless of the setting, when <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code> is
1973 used for controlling access by hostname, a double reverse lookup
1974 will be performed. This is necessary for security. Note that the
1975 result of this double-reverse isn't generally available unless you
1976 set <code>HostnameLookups Double</code>. For example, if only
1977 <code>HostnameLookups On</code> and a request is made to an object
1978 that is protected by hostname restrictions, regardless of whether
1979 the double-reverse fails or not, CGIs will still be passed the
1980 single-reverse result in <code>REMOTE_HOST</code>.</p>
1982 <p>The default is <code>Off</code> in order to save the network
1983 traffic for those sites that don't truly need the reverse
1984 lookups done. It is also better for the end users because they
1985 don't have to suffer the extra latency that a lookup entails.
1986 Heavily loaded sites should leave this directive
1987 <code>Off</code>, since DNS lookups can take considerable
1988 amounts of time. The utility <code class="program"><a href="../programs/logresolve.html">logresolve</a></code>, compiled by
1989 default to the <code>bin</code> subdirectory of your installation
1990 directory, can be used to look up host names from logged IP addresses
1993 <p>Finally, if you have <a href="mod_authz_host.html#reqhost">hostname-based Require
1994 directives</a>, a hostname lookup will be performed regardless of
1995 the setting of <code>HostnameLookups</code>.</p>
1998 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1999 <div class="directive-section"><h2><a name="If" id="If"><If></a> <a name="if" id="if">Directive</a></h2>
2000 <table class="directive">
2001 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is
2002 satisfied by a request at runtime</td></tr>
2003 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><If <var>expression</var>> ... </If></code></td></tr>
2004 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2005 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2006 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2007 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2009 <p>The <code class="directive"><If></code> directive
2010 evaluates an expression at runtime, and applies the enclosed
2011 directives if and only if the expression evaluates to true.
2014 <pre class="prettyprint lang-config"><If "-z req('Host')"></pre>
2017 <p>would match HTTP/1.0 requests without a <var>Host:</var> header.
2018 Expressions may contain various shell-like operators for string
2019 comparison (<code>==</code>, <code>!=</code>, <code><</code>, ...),
2020 integer comparison (<code>-eq</code>, <code>-ne</code>, ...),
2021 and others (<code>-n</code>, <code>-z</code>, <code>-f</code>, ...).
2022 It is also possible to use regular expressions, </p>
2024 <pre class="prettyprint lang-config"><If "%{QUERY_STRING} =~ /(delete|commit)=.*?elem/"></pre>
2027 <p>shell-like pattern matches and many other operations. These operations
2028 can be done on request headers (<code>req</code>), environment variables
2029 (<code>env</code>), and a large number of other properties. The full
2030 documentation is available in <a href="../expr.html">Expressions in
2031 Apache HTTP Server</a>.</p>
2033 <p>Only directives that support the <a href="directive-dict.html#Context">directory context</a> can be used within this configuration section.</p>
2035 <div class="warning">
2036 Certain variables, such as <code>CONTENT_TYPE</code> and other
2037 response headers, are set after <If> conditions have already
2038 been evaluated, and so will not be available to use in this
2045 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
2046 for a complete reference and more examples.</li>
2047 <li><code class="directive"><a href="#elseif"><ElseIf></a></code></li>
2048 <li><code class="directive"><a href="#else"><Else></a></code></li>
2049 <li><a href="../sections.html">How <Directory>, <Location>,
2050 <Files> sections work</a> for an explanation of how these
2051 different sections are combined when a request is received.
2052 <code class="directive"><If></code>,
2053 <code class="directive"><ElseIf></code>, and
2054 <code class="directive"><Else></code> are applied last.</li>
2057 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2058 <div class="directive-section"><h2><a name="IfDefine" id="IfDefine"><IfDefine></a> <a name="ifdefine" id="ifdefine">Directive</a></h2>
2059 <table class="directive">
2060 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that will be processed only
2061 if a test is true at startup</td></tr>
2062 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfDefine [!]<var>parameter-name</var>> ...
2063 </IfDefine></code></td></tr>
2064 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2065 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2066 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2067 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2069 <p>The <code><IfDefine <var>test</var>>...</IfDefine>
2070 </code> section is used to mark directives that are conditional. The
2071 directives within an <code class="directive"><IfDefine></code>
2072 section are only processed if the <var>test</var> is true. If <var>
2073 test</var> is false, everything between the start and end markers is
2076 <p>The <var>test</var> in the <code class="directive"><IfDefine></code> section directive can be one of two forms:</p>
2079 <li><var>parameter-name</var></li>
2081 <li><code>!</code><var>parameter-name</var></li>
2084 <p>In the former case, the directives between the start and end
2085 markers are only processed if the parameter named
2086 <var>parameter-name</var> is defined. The second format reverses
2087 the test, and only processes the directives if
2088 <var>parameter-name</var> is <strong>not</strong> defined.</p>
2090 <p>The <var>parameter-name</var> argument is a define as given on the
2091 <code class="program"><a href="../programs/httpd.html">httpd</a></code> command line via <code>-D<var>parameter</var>
2092 </code> at the time the server was started or by the <code class="directive"><a href="#define">Define</a></code> directive.</p>
2094 <p><code class="directive"><IfDefine></code> sections are
2095 nest-able, which can be used to implement simple
2096 multiple-parameter tests. Example:</p>
2098 <div class="example"><p><code>httpd -DReverseProxy -DUseCache -DMemCache ...</code></p></div>
2099 <pre class="prettyprint lang-config"><IfDefine ReverseProxy>
2100 LoadModule proxy_module modules/mod_proxy.so
2101 LoadModule proxy_http_module modules/mod_proxy_http.so
2102 <IfDefine UseCache>
2103 LoadModule cache_module modules/mod_cache.so
2104 <IfDefine MemCache>
2105 LoadModule mem_cache_module modules/mod_mem_cache.so
2107 <IfDefine !MemCache>
2108 LoadModule cache_disk_module modules/mod_cache_disk.so
2111 </IfDefine></pre>
2115 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2116 <div class="directive-section"><h2><a name="IfModule" id="IfModule"><IfModule></a> <a name="ifmodule" id="ifmodule">Directive</a></h2>
2117 <table class="directive">
2118 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that are processed conditional on the
2119 presence or absence of a specific module</td></tr>
2120 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfModule [!]<var>module-file</var>|<var>module-identifier</var>> ...
2121 </IfModule></code></td></tr>
2122 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2123 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2124 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2125 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2127 <p>The <code><IfModule <var>test</var>>...</IfModule></code>
2128 section is used to mark directives that are conditional on the presence of
2129 a specific module. The directives within an <code class="directive"><IfModule></code> section are only processed if the <var>test</var>
2130 is true. If <var>test</var> is false, everything between the start and
2131 end markers is ignored.</p>
2133 <p>The <var>test</var> in the <code class="directive"><IfModule></code> section directive can be one of two forms:</p>
2136 <li><var>module</var></li>
2138 <li>!<var>module</var></li>
2141 <p>In the former case, the directives between the start and end
2142 markers are only processed if the module named <var>module</var>
2143 is included in Apache httpd -- either compiled in or
2144 dynamically loaded using <code class="directive"><a href="../mod/mod_so.html#loadmodule">LoadModule</a></code>. The second format reverses the test,
2145 and only processes the directives if <var>module</var> is
2146 <strong>not</strong> included.</p>
2148 <p>The <var>module</var> argument can be either the module identifier or
2149 the file name of the module, at the time it was compiled. For example,
2150 <code>rewrite_module</code> is the identifier and
2151 <code>mod_rewrite.c</code> is the file name. If a module consists of
2152 several source files, use the name of the file containing the string
2153 <code>STANDARD20_MODULE_STUFF</code>.</p>
2155 <p><code class="directive"><IfModule></code> sections are
2156 nest-able, which can be used to implement simple multiple-module
2159 <div class="note">This section should only be used if you need to have one
2160 configuration file that works whether or not a specific module
2161 is available. In normal operation, directives need not be
2162 placed in <code class="directive"><IfModule></code>
2166 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2167 <div class="directive-section"><h2><a name="Include" id="Include">Include</a> <a name="include" id="include">Directive</a></h2>
2168 <table class="directive">
2169 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2170 the server configuration files</td></tr>
2171 <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>
2172 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2173 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2174 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2175 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Directory
2176 wildcard matching available in 2.3.6 and later</td></tr>
2178 <p>This directive allows inclusion of other configuration files
2179 from within the server configuration files.</p>
2181 <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used
2182 in the filename or directory parts of the path to include several files
2183 at once, in alphabetical order. In addition, if
2184 <code class="directive">Include</code> points to a directory, rather than a file,
2185 Apache httpd will read all files in that directory and any subdirectory.
2186 However, including entire directories is not recommended, because it is
2187 easy to accidentally leave temporary files in a directory that can cause
2188 <code class="program"><a href="../programs/httpd.html">httpd</a></code> to fail. Instead, we encourage you to use the
2189 wildcard syntax shown below, to include files that match a particular
2190 pattern, such as *.conf, for example.</p>
2192 <p>The <code class="directive"><a href="#include">Include</a></code> directive will
2193 <strong>fail with an error</strong> if a wildcard expression does not
2194 match any file. The <code class="directive"><a href="#includeoptional">IncludeOptional</a></code>
2195 directive can be used if non-matching wildcards should be ignored.</p>
2197 <p>The file path specified may be an absolute path, or may be relative
2198 to the <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory.</p>
2202 <pre class="prettyprint lang-config">Include /usr/local/apache2/conf/ssl.conf
2203 Include /usr/local/apache2/conf/vhosts/*.conf</pre>
2206 <p>Or, providing paths relative to your <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory:</p>
2208 <pre class="prettyprint lang-config">Include conf/ssl.conf
2209 Include conf/vhosts/*.conf</pre>
2212 <p>Wildcards may be included in the directory or file portion of the
2213 path. This example will fail if there is no subdirectory in conf/vhosts
2214 that contains at least one *.conf file:</p>
2216 <pre class="prettyprint lang-config">Include conf/vhosts/*/*.conf</pre>
2219 <p>Alternatively, the following command will just be ignored in case of
2220 missing files or directories:</p>
2222 <pre class="prettyprint lang-config">IncludeOptional conf/vhosts/*/*.conf</pre>
2228 <li><code class="directive"><a href="#includeoptional">IncludeOptional</a></code></li>
2229 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2232 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2233 <div class="directive-section"><h2><a name="IncludeOptional" id="IncludeOptional">IncludeOptional</a> <a name="includeoptional" id="includeoptional">Directive</a></h2>
2234 <table class="directive">
2235 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2236 the server configuration files</td></tr>
2237 <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>
2238 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</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>
2241 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in 2.3.6 and later</td></tr>
2243 <p>This directive allows inclusion of other configuration files
2244 from within the server configuration files. It works identically to the
2245 <code class="directive"><a href="#include">Include</a></code> directive, with the
2246 exception that if wildcards do not match any file or directory, the
2247 <code class="directive"><a href="#includeoptional">IncludeOptional</a></code> directive will be
2248 silently ignored instead of causing an error.</p>
2252 <li><code class="directive"><a href="#include">Include</a></code></li>
2253 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2256 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2257 <div class="directive-section"><h2><a name="KeepAlive" id="KeepAlive">KeepAlive</a> <a name="keepalive" id="keepalive">Directive</a></h2>
2258 <table class="directive">
2259 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables HTTP persistent connections</td></tr>
2260 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAlive On|Off</code></td></tr>
2261 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAlive On</code></td></tr>
2262 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2263 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2264 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2266 <p>The Keep-Alive extension to HTTP/1.0 and the persistent
2267 connection feature of HTTP/1.1 provide long-lived HTTP sessions
2268 which allow multiple requests to be sent over the same TCP
2269 connection. In some cases this has been shown to result in an
2270 almost 50% speedup in latency times for HTML documents with
2271 many images. To enable Keep-Alive connections, set
2272 <code>KeepAlive On</code>.</p>
2274 <p>For HTTP/1.0 clients, Keep-Alive connections will only be
2275 used if they are specifically requested by a client. In
2276 addition, a Keep-Alive connection with an HTTP/1.0 client can
2277 only be used when the length of the content is known in
2278 advance. This implies that dynamic content such as CGI output,
2279 SSI pages, and server-generated directory listings will
2280 generally not use Keep-Alive connections to HTTP/1.0 clients.
2281 For HTTP/1.1 clients, persistent connections are the default
2282 unless otherwise specified. If the client requests it, chunked
2283 encoding will be used in order to send content of unknown
2284 length over persistent connections.</p>
2286 <p>When a client uses a Keep-Alive connection, it will be counted
2287 as a single "request" for the <code class="directive"><a href="../mod/mpm_common.html#maxconnectionsperchild">MaxConnectionsPerChild</a></code> directive, regardless
2288 of how many requests are sent using the connection.</p>
2292 <li><code class="directive"><a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></code></li>
2295 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2296 <div class="directive-section"><h2><a name="KeepAliveTimeout" id="KeepAliveTimeout">KeepAliveTimeout</a> <a name="keepalivetimeout" id="keepalivetimeout">Directive</a></h2>
2297 <table class="directive">
2298 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for subsequent
2299 requests on a persistent connection</td></tr>
2300 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAliveTimeout <var>num</var>[ms]</code></td></tr>
2301 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAliveTimeout 5</code></td></tr>
2302 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2303 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2304 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2306 <p>The number of seconds Apache httpd will wait for a subsequent
2307 request before closing the connection. By adding a postfix of ms the
2308 timeout can be also set in milliseconds. Once a request has been
2309 received, the timeout value specified by the
2310 <code class="directive"><a href="#timeout">Timeout</a></code> directive applies.</p>
2312 <p>Setting <code class="directive">KeepAliveTimeout</code> to a high value
2313 may cause performance problems in heavily loaded servers. The
2314 higher the timeout, the more server processes will be kept
2315 occupied waiting on connections with idle clients.</p>
2317 <p>If <code class="directive">KeepAliveTimeout</code> is <strong>not</strong>
2318 set for a name-based virtual host, the value of the first defined
2319 virtual host best matching the local IP and port will be used.</p>
2322 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2323 <div class="directive-section"><h2><a name="Limit" id="Limit"><Limit></a> <a name="limit" id="limit">Directive</a></h2>
2324 <table class="directive">
2325 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict enclosed access controls to only certain HTTP
2327 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Limit <var>method</var> [<var>method</var>] ... > ...
2328 </Limit></code></td></tr>
2329 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2330 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2331 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2332 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2334 <p>Access controls are normally effective for
2335 <strong>all</strong> access methods, and this is the usual
2336 desired behavior. <strong>In the general case, access control
2337 directives should not be placed within a
2338 <code class="directive"><Limit></code> section.</strong></p>
2340 <p>The purpose of the <code class="directive"><Limit></code>
2341 directive is to restrict the effect of the access controls to the
2342 nominated HTTP methods. For all other methods, the access
2343 restrictions that are enclosed in the <code class="directive"><Limit></code> bracket <strong>will have no
2344 effect</strong>. The following example applies the access control
2345 only to the methods <code>POST</code>, <code>PUT</code>, and
2346 <code>DELETE</code>, leaving all other methods unprotected:</p>
2348 <pre class="prettyprint lang-config"><Limit POST PUT DELETE>
2350 </Limit></pre>
2353 <p>The method names listed can be one or more of: <code>GET</code>,
2354 <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
2355 <code>CONNECT</code>, <code>OPTIONS</code>,
2356 <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
2357 <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
2358 <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
2359 case-sensitive.</strong> If <code>GET</code> is used, it will also
2360 restrict <code>HEAD</code> requests. The <code>TRACE</code> method
2361 cannot be limited (see <code class="directive"><a href="#traceenable">TraceEnable</a></code>).</p>
2363 <div class="warning">A <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section should always be
2364 used in preference to a <code class="directive"><Limit></code>
2365 section when restricting access, since a <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section provides protection
2366 against arbitrary methods.</div>
2368 <p>The <code class="directive"><Limit></code> and
2369 <code class="directive"><a href="#limitexcept"><LimitExcept></a></code>
2370 directives may be nested. In this case, each successive level of
2371 <code class="directive"><Limit></code> or <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> directives must
2372 further restrict the set of methods to which access controls apply.</p>
2374 <div class="warning">When using
2375 <code class="directive"><Limit></code> or
2376 <code class="directive"><LimitExcept></code> directives with
2377 the <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directive,
2378 note that the first <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code>
2379 to succeed authorizes the request, regardless of the presence of other
2380 <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directives.</div>
2382 <p>For example, given the following configuration, all users will
2383 be authorized for <code>POST</code> requests, and the
2384 <code>Require group editors</code> directive will be ignored
2387 <pre class="prettyprint lang-config"><LimitExcept GET>
2389 </LimitExcept>
2391 Require group editors
2392 </Limit></pre>
2396 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2397 <div class="directive-section"><h2><a name="LimitExcept" id="LimitExcept"><LimitExcept></a> <a name="limitexcept" id="limitexcept">Directive</a></h2>
2398 <table class="directive">
2399 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict access controls to all HTTP methods
2400 except the named ones</td></tr>
2401 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LimitExcept <var>method</var> [<var>method</var>] ... > ...
2402 </LimitExcept></code></td></tr>
2403 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2404 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2405 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2406 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2408 <p><code class="directive"><LimitExcept></code> and
2409 <code></LimitExcept></code> are used to enclose
2410 a group of access control directives which will then apply to any
2411 HTTP access method <strong>not</strong> listed in the arguments;
2412 i.e., it is the opposite of a <code class="directive"><a href="#limit"><Limit></a></code> section and can be used to control
2413 both standard and nonstandard/unrecognized methods. See the
2414 documentation for <code class="directive"><a href="#limit"><Limit></a></code> for more details.</p>
2418 <pre class="prettyprint lang-config"><LimitExcept POST GET>
2420 </LimitExcept></pre>
2425 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2426 <div class="directive-section"><h2><a name="LimitInternalRecursion" id="LimitInternalRecursion">LimitInternalRecursion</a> <a name="limitinternalrecursion" id="limitinternalrecursion">Directive</a></h2>
2427 <table class="directive">
2428 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine maximum number of internal redirects and nested
2429 subrequests</td></tr>
2430 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitInternalRecursion <var>number</var> [<var>number</var>]</code></td></tr>
2431 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitInternalRecursion 10</code></td></tr>
2432 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2433 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2434 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2436 <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
2437 redirects the original request to a CGI script. A subrequest is Apache httpd's
2438 mechanism to find out what would happen for some URI if it were requested.
2439 For example, <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> uses subrequests to look for the
2440 files listed in the <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
2443 <p><code class="directive">LimitInternalRecursion</code> prevents the server
2444 from crashing when entering an infinite loop of internal redirects or
2445 subrequests. Such loops are usually caused by misconfigurations.</p>
2447 <p>The directive stores two different limits, which are evaluated on
2448 per-request basis. The first <var>number</var> is the maximum number of
2449 internal redirects that may follow each other. The second <var>number</var>
2450 determines how deeply subrequests may be nested. If you specify only one
2451 <var>number</var>, it will be assigned to both limits.</p>
2453 <pre class="prettyprint lang-config">LimitInternalRecursion 5</pre>
2457 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2458 <div class="directive-section"><h2><a name="LimitRequestBody" id="LimitRequestBody">LimitRequestBody</a> <a name="limitrequestbody" id="limitrequestbody">Directive</a></h2>
2459 <table class="directive">
2460 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restricts the total size of the HTTP request body sent
2461 from the client</td></tr>
2462 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestBody <var>bytes</var></code></td></tr>
2463 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestBody 0</code></td></tr>
2464 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2465 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2466 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2467 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2469 <p>This directive specifies the number of <var>bytes</var> from 0
2470 (meaning unlimited) to 2147483647 (2GB) that are allowed in a
2471 request body. See the note below for the limited applicability
2472 to proxy requests.</p>
2474 <p>The <code class="directive">LimitRequestBody</code> directive allows
2475 the user to set a limit on the allowed size of an HTTP request
2476 message body within the context in which the directive is given
2477 (server, per-directory, per-file or per-location). If the client
2478 request exceeds that limit, the server will return an error
2479 response instead of servicing the request. The size of a normal
2480 request message body will vary greatly depending on the nature of
2481 the resource and the methods allowed on that resource. CGI scripts
2482 typically use the message body for retrieving form information.
2483 Implementations of the <code>PUT</code> method will require
2484 a value at least as large as any representation that the server
2485 wishes to accept for that resource.</p>
2487 <p>This directive gives the server administrator greater
2488 control over abnormal client request behavior, which may be
2489 useful for avoiding some forms of denial-of-service
2492 <p>If, for example, you are permitting file upload to a particular
2493 location and wish to limit the size of the uploaded file to 100K,
2494 you might use the following directive:</p>
2496 <pre class="prettyprint lang-config">LimitRequestBody 102400</pre>
2499 <div class="note"><p>For a full description of how this directive is interpreted by
2500 proxy requests, see the <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> documentation.</p>
2505 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2506 <div class="directive-section"><h2><a name="LimitRequestFields" id="LimitRequestFields">LimitRequestFields</a> <a name="limitrequestfields" id="limitrequestfields">Directive</a></h2>
2507 <table class="directive">
2508 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of HTTP request header fields that
2509 will be accepted from the client</td></tr>
2510 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFields <var>number</var></code></td></tr>
2511 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFields 100</code></td></tr>
2512 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2513 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2514 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2516 <p><var>Number</var> is an integer from 0 (meaning unlimited) to
2517 32767. The default value is defined by the compile-time
2518 constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
2521 <p>The <code class="directive">LimitRequestFields</code> directive allows
2522 the server administrator to modify the limit on the number of
2523 request header fields allowed in an HTTP request. A server needs
2524 this value to be larger than the number of fields that a normal
2525 client request might include. The number of request header fields
2526 used by a client rarely exceeds 20, but this may vary among
2527 different client implementations, often depending upon the extent
2528 to which a user has configured their browser to support detailed
2529 content negotiation. Optional HTTP extensions are often expressed
2530 using request header fields.</p>
2532 <p>This directive gives the server administrator greater
2533 control over abnormal client request behavior, which may be
2534 useful for avoiding some forms of denial-of-service attacks.
2535 The value should be increased if normal clients see an error
2536 response from the server that indicates too many fields were
2537 sent in the request.</p>
2541 <pre class="prettyprint lang-config">LimitRequestFields 50</pre>
2544 <div class="warning"><h3>Warning</h3>
2545 <p> When name-based virtual hosting is used, the value for this
2546 directive is taken from the default (first-listed) virtual host for the
2547 local IP and port combination.</p>
2552 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2553 <div class="directive-section"><h2><a name="LimitRequestFieldSize" id="LimitRequestFieldSize">LimitRequestFieldSize</a> <a name="limitrequestfieldsize" id="limitrequestfieldsize">Directive</a></h2>
2554 <table class="directive">
2555 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of the HTTP request header allowed from the
2557 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFieldSize <var>bytes</var></code></td></tr>
2558 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFieldSize 8190</code></td></tr>
2559 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2560 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2561 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2563 <p>This directive specifies the number of <var>bytes</var>
2564 that will be allowed in an HTTP request header.</p>
2566 <p>The <code class="directive">LimitRequestFieldSize</code> directive
2567 allows the server administrator to set the limit
2568 on the allowed size of an HTTP request header field. A server
2569 needs this value to be large enough to hold any one header field
2570 from a normal client request. The size of a normal request header
2571 field will vary greatly among different client implementations,
2572 often depending upon the extent to which a user has configured
2573 their browser to support detailed content negotiation. SPNEGO
2574 authentication headers can be up to 12392 bytes.</p>
2576 <p>This directive gives the server administrator greater
2577 control over abnormal client request behavior, which may be
2578 useful for avoiding some forms of denial-of-service attacks.</p>
2582 <pre class="prettyprint lang-config">LimitRequestFieldSize 4094</pre>
2585 <div class="note">Under normal conditions, the value should not be changed from
2588 <div class="warning"><h3>Warning</h3>
2589 <p> When name-based virtual hosting is used, the value for this
2590 directive is taken from the default (first-listed) virtual host best
2591 matching the current IP address and port combination.</p>
2595 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2596 <div class="directive-section"><h2><a name="LimitRequestLine" id="LimitRequestLine">LimitRequestLine</a> <a name="limitrequestline" id="limitrequestline">Directive</a></h2>
2597 <table class="directive">
2598 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limit the size of the HTTP request line that will be accepted
2599 from the client</td></tr>
2600 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestLine <var>bytes</var></code></td></tr>
2601 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestLine 8190</code></td></tr>
2602 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2603 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2604 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2606 <p>This directive sets the number of <var>bytes</var> that will be
2607 allowed on the HTTP request-line.</p>
2609 <p>The <code class="directive">LimitRequestLine</code> directive allows
2610 the server administrator to set the limit on the allowed size
2611 of a client's HTTP request-line. Since the request-line consists of the
2612 HTTP method, URI, and protocol version, the
2613 <code class="directive">LimitRequestLine</code> directive places a
2614 restriction on the length of a request-URI allowed for a request
2615 on the server. A server needs this value to be large enough to
2616 hold any of its resource names, including any information that
2617 might be passed in the query part of a <code>GET</code> request.</p>
2619 <p>This directive gives the server administrator greater
2620 control over abnormal client request behavior, which may be
2621 useful for avoiding some forms of denial-of-service attacks.</p>
2625 <pre class="prettyprint lang-config">LimitRequestLine 4094</pre>
2628 <div class="note">Under normal conditions, the value should not be changed from
2631 <div class="warning"><h3>Warning</h3>
2632 <p> When name-based virtual hosting is used, the value for this
2633 directive is taken from the default (first-listed) virtual host best
2634 matching the current IP address and port combination.</p>
2639 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2640 <div class="directive-section"><h2><a name="LimitXMLRequestBody" id="LimitXMLRequestBody">LimitXMLRequestBody</a> <a name="limitxmlrequestbody" id="limitxmlrequestbody">Directive</a></h2>
2641 <table class="directive">
2642 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of an XML-based request body</td></tr>
2643 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitXMLRequestBody <var>bytes</var></code></td></tr>
2644 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitXMLRequestBody 1000000</code></td></tr>
2645 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2646 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2647 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2648 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2650 <p>Limit (in bytes) on maximum size of an XML-based request
2651 body. A value of <code>0</code> will disable any checking.</p>
2655 <pre class="prettyprint lang-config">LimitXMLRequestBody 0</pre>
2660 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2661 <div class="directive-section"><h2><a name="Location" id="Location"><Location></a> <a name="location" id="location">Directive</a></h2>
2662 <table class="directive">
2663 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to matching
2665 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Location
2666 <var>URL-path</var>|<var>URL</var>> ... </Location></code></td></tr>
2667 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2668 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2669 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2671 <p>The <code class="directive"><Location></code> directive
2672 limits the scope of the enclosed directives by URL. It is similar to the
2673 <code class="directive"><a href="#directory"><Directory></a></code>
2674 directive, and starts a subsection which is terminated with a
2675 <code></Location></code> directive. <code class="directive"><Location></code> sections are processed in the
2676 order they appear in the configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
2677 <code>.htaccess</code> files are read, and after the <code class="directive"><a href="#files"><Files></a></code> sections.</p>
2679 <p><code class="directive"><Location></code> sections operate
2680 completely outside the filesystem. This has several consequences.
2681 Most importantly, <code class="directive"><Location></code>
2682 directives should not be used to control access to filesystem
2683 locations. Since several different URLs may map to the same
2684 filesystem location, such access controls may by circumvented.</p>
2686 <p>The enclosed directives will be applied to the request if the path component
2687 of the URL meets <em>any</em> of the following criteria:
2690 <li>The specified location matches exactly the path component of the URL.
2692 <li>The specified location, which ends in a forward slash, is a prefix
2693 of the path component of the URL (treated as a context root).
2695 <li>The specified location, with the addition of a trailing slash, is a
2696 prefix of the path component of the URL (also treated as a context root).
2700 In the example below, where no trailing slash is used, requests to
2701 /private1, /private1/ and /private1/file.txt will have the enclosed
2702 directives applied, but /private1other would not.
2704 <pre class="prettyprint lang-config"><Location "/private1">
2706 </Location></pre>
2709 In the example below, where a trailing slash is used, requests to
2710 /private2/ and /private2/file.txt will have the enclosed
2711 directives applied, but /private2 and /private2other would not.
2713 <pre class="prettyprint lang-config"><Location "/private2<em>/</em>">
2715 </Location></pre>
2718 <div class="note"><h3>When to use <code class="directive"><Location></code></h3>
2720 <p>Use <code class="directive"><Location></code> to apply
2721 directives to content that lives outside the filesystem. For
2722 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
2723 <code><Location "/"></code>, which is an easy way to
2724 apply a configuration to the entire server.</p>
2727 <p>For all origin (non-proxy) requests, the URL to be matched is a
2728 URL-path of the form <code>/path/</code>. <em>No scheme, hostname,
2729 port, or query string may be included.</em> For proxy requests, the
2730 URL to be matched is of the form
2731 <code>scheme://servername/path</code>, and you must include the
2734 <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
2735 any single character, and <code>*</code> matches any sequences of
2736 characters. Neither wildcard character matches a / in the URL-path.</p>
2738 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
2739 can also be used, with the addition of the <code>~</code>
2740 character. For example:</p>
2742 <pre class="prettyprint lang-config"><Location ~ "/(extra|special)/data">
2744 </Location></pre>
2747 <p>would match URLs that contained the substring <code>/extra/data</code>
2748 or <code>/special/data</code>. The directive <code class="directive"><a href="#locationmatch"><LocationMatch></a></code> behaves
2749 identical to the regex version of <code class="directive"><Location></code>, and is preferred, for the
2750 simple reason that <code>~</code> is hard to distinguish from
2751 <code>-</code> in many fonts.</p>
2753 <p>The <code class="directive"><Location></code>
2754 functionality is especially useful when combined with the
2755 <code class="directive"><a href="#sethandler">SetHandler</a></code>
2756 directive. For example, to enable status requests but allow them
2757 only from browsers at <code>example.com</code>, you might use:</p>
2759 <pre class="prettyprint lang-config"><Location "/status">
2760 SetHandler server-status
2761 Require host example.com
2762 </Location></pre>
2765 <div class="note"><h3>Note about / (slash)</h3>
2766 <p>The slash character has special meaning depending on where in a
2767 URL it appears. People may be used to its behavior in the filesystem
2768 where multiple adjacent slashes are frequently collapsed to a single
2769 slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
2770 <code>/home/foo</code>). In URL-space this is not necessarily true.
2771 The <code class="directive"><a href="#locationmatch"><LocationMatch></a></code>
2772 directive and the regex version of <code class="directive"><Location></code> require you to explicitly specify multiple
2773 slashes if that is your intention.</p>
2775 <p>For example, <code><LocationMatch "^/abc"></code> would match
2776 the request URL <code>/abc</code> but not the request URL <code>
2777 //abc</code>. The (non-regex) <code class="directive"><Location></code> directive behaves similarly when used for
2778 proxy requests. But when (non-regex) <code class="directive"><Location></code> is used for non-proxy requests it will
2779 implicitly match multiple slashes with a single slash. For example,
2780 if you specify <code><Location "/abc/def"></code> and the
2781 request is to <code>/abc//def</code> then it will match.</p>
2786 <li><a href="../sections.html">How <Directory>, <Location>
2787 and <Files> sections work</a> for an explanation of how these
2788 different sections are combined when a request is received.</li>
2789 <li><code class="directive"><a href="#locationmatch">LocationMatch</a></code></li>
2792 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2793 <div class="directive-section"><h2><a name="LocationMatch" id="LocationMatch"><LocationMatch></a> <a name="locationmatch" id="locationmatch">Directive</a></h2>
2794 <table class="directive">
2795 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to regular-expression
2796 matching URLs</td></tr>
2797 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LocationMatch
2798 <var>regex</var>> ... </LocationMatch></code></td></tr>
2799 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2800 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2801 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2803 <p>The <code class="directive"><LocationMatch></code> directive
2804 limits the scope of the enclosed directives by URL, in an identical manner
2805 to <code class="directive"><a href="#location"><Location></a></code>. However,
2806 it takes a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
2807 as an argument instead of a simple string. For example:</p>
2809 <pre class="prettyprint lang-config"><LocationMatch "/(extra|special)/data">
2811 </LocationMatch></pre>
2814 <p>would match URLs that contained the substring <code>/extra/data</code>
2815 or <code>/special/data</code>.</p>
2817 <div class="note"><p>If the intent is that a URL <strong>starts with</strong>
2818 <code>/extra/data</code>, rather than merely
2819 <strong>contains</strong> <code>/extra/data</code>, prefix the
2820 regular expression with a <code>^</code> to require this.</p>
2822 <pre class="prettyprint lang-config"><LocationMatch "^/(extra|special)/data"></pre>
2826 <p>From 2.4.8 onwards, named groups and backreferences are captured and
2827 written to the environment with the corresponding name prefixed with
2828 "MATCH_" and in upper case. This allows elements of URLs to be referenced
2829 from within <a href="../expr.html">expressions</a> and modules like
2830 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
2831 (unnamed) backreferences are ignored. Use named groups instead.</p>
2833 <pre class="prettyprint lang-config"><LocationMatch "^/combined/(?<sitename>[^/]+)">
2834 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
2835 </LocationMatch></pre>
2840 <li><a href="../sections.html">How <Directory>, <Location>
2841 and <Files> sections work</a> for an explanation of how these
2842 different sections are combined when a request is received</li>
2845 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2846 <div class="directive-section"><h2><a name="LogLevel" id="LogLevel">LogLevel</a> <a name="loglevel" id="loglevel">Directive</a></h2>
2847 <table class="directive">
2848 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Controls the verbosity of the ErrorLog</td></tr>
2849 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel [<var>module</var>:]<var>level</var>
2850 [<var>module</var>:<var>level</var>] ...
2852 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LogLevel warn</code></td></tr>
2853 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2854 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2855 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2856 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Per-module and per-directory configuration is available in
2857 Apache HTTP Server 2.3.6 and later</td></tr>
2859 <p><code class="directive">LogLevel</code> adjusts the verbosity of the
2860 messages recorded in the error logs (see <code class="directive"><a href="#errorlog">ErrorLog</a></code> directive). The following
2861 <var>level</var>s are available, in order of decreasing
2864 <table class="bordered">
2867 <th><strong>Level</strong> </th>
2869 <th><strong>Description</strong> </th>
2871 <th><strong>Example</strong> </th>
2875 <td><code>emerg</code> </td>
2877 <td>Emergencies - system is unusable.</td>
2879 <td>"Child cannot open lock file. Exiting"</td>
2883 <td><code>alert</code> </td>
2885 <td>Action must be taken immediately.</td>
2887 <td>"getpwuid: couldn't determine user name from uid"</td>
2891 <td><code>crit</code> </td>
2893 <td>Critical Conditions.</td>
2895 <td>"socket: Failed to get a socket, exiting child"</td>
2899 <td><code>error</code> </td>
2901 <td>Error conditions.</td>
2903 <td>"Premature end of script headers"</td>
2907 <td><code>warn</code> </td>
2909 <td>Warning conditions.</td>
2911 <td>"child process 1234 did not exit, sending another
2916 <td><code>notice</code> </td>
2918 <td>Normal but significant condition.</td>
2920 <td>"httpd: caught SIGBUS, attempting to dump core in
2925 <td><code>info</code> </td>
2927 <td>Informational.</td>
2929 <td>"Server seems busy, (you may need to increase
2930 StartServers, or Min/MaxSpareServers)..."</td>
2934 <td><code>debug</code> </td>
2936 <td>Debug-level messages</td>
2938 <td>"Opening config file ..."</td>
2941 <td><code>trace1</code> </td>
2943 <td>Trace messages</td>
2945 <td>"proxy: FTP: control connection complete"</td>
2948 <td><code>trace2</code> </td>
2950 <td>Trace messages</td>
2952 <td>"proxy: CONNECT: sending the CONNECT request to the remote proxy"</td>
2955 <td><code>trace3</code> </td>
2957 <td>Trace messages</td>
2959 <td>"openssl: Handshake: start"</td>
2962 <td><code>trace4</code> </td>
2964 <td>Trace messages</td>
2966 <td>"read from buffered SSL brigade, mode 0, 17 bytes"</td>
2969 <td><code>trace5</code> </td>
2971 <td>Trace messages</td>
2973 <td>"map lookup FAILED: map=rewritemap key=keyname"</td>
2976 <td><code>trace6</code> </td>
2978 <td>Trace messages</td>
2980 <td>"cache lookup FAILED, forcing new map lookup"</td>
2983 <td><code>trace7</code> </td>
2985 <td>Trace messages, dumping large amounts of data</td>
2987 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2990 <td><code>trace8</code> </td>
2992 <td>Trace messages, dumping large amounts of data</td>
2994 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2998 <p>When a particular level is specified, messages from all
2999 other levels of higher significance will be reported as well.
3000 <em>E.g.</em>, when <code>LogLevel info</code> is specified,
3001 then messages with log levels of <code>notice</code> and
3002 <code>warn</code> will also be posted.</p>
3004 <p>Using a level of at least <code>crit</code> is
3009 <pre class="prettyprint lang-config">LogLevel notice</pre>
3012 <div class="note"><h3>Note</h3>
3013 <p>When logging to a regular file, messages of the level
3014 <code>notice</code> cannot be suppressed and thus are always
3015 logged. However, this doesn't apply when logging is done
3016 using <code>syslog</code>.</p>
3019 <p>Specifying a level without a module name will reset the level
3020 for all modules to that level. Specifying a level with a module
3021 name will set the level for that module only. It is possible to
3022 use the module source file name, the module identifier, or the
3023 module identifier with the trailing <code>_module</code> omitted
3024 as module specification. This means the following three specifications
3027 <pre class="prettyprint lang-config">LogLevel info ssl:warn
3028 LogLevel info mod_ssl.c:warn
3029 LogLevel info ssl_module:warn</pre>
3032 <p>It is also possible to change the level per directory:</p>
3034 <pre class="prettyprint lang-config">LogLevel info
3035 <Directory "/usr/local/apache/htdocs/app">
3037 </Directory></pre>
3041 Per directory loglevel configuration only affects messages that are
3042 logged after the request has been parsed and that are associated with
3043 the request. Log messages which are associated with the server or
3044 the connection are not affected. The latter can be influenced by the
3045 <code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code> directive,
3051 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
3052 <li><code class="directive"><a href="#errorlogformat">ErrorLogFormat</a></code></li>
3053 <li><code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code></li>
3054 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
3057 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3058 <div class="directive-section"><h2><a name="LogLevelOverride" id="LogLevelOverride">LogLevelOverride</a> <a name="logleveloverride" id="logleveloverride">Directive</a></h2>
3059 <table class="directive">
3060 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Override the verbosity of the ErrorLog for certain clients</td></tr>
3061 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel <var>ipaddress</var>[/<var>prefixlen</var>]
3062 [<var>module</var>:]<var>level</var> [<var>module</var>:<var>level</var>] ...
3064 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>unset</code></td></tr>
3065 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3066 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3067 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3068 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.5.0 and later</td></tr>
3070 <p><code class="directive">LogLevelOverride</code> adjusts the
3071 <code class="directive"><a href="#loglevel">LogLevel</a></code> for requests coming from
3072 certain client IP addresses.
3073 This allows to enable verbose logging only for certain test clients.
3074 The IP address is checked at a very early state in the connection
3075 processing. Therefore, <code class="directive">LogLevelOverride</code> allows to
3076 change the log level for things like the SSL handshake which happen before
3077 a <code class="directive"><a href="#loglevel">LogLevel</a></code> directive in an
3078 <code class="directive"><a href="#if"><If></a></code> container would
3081 <p><code class="directive">LogLevelOverride</code> accepts either a single
3082 IP-address or a CIDR IP-address/len subnet specification.
3083 For the syntax of the loglevel specification, see the
3084 <code class="directive"><a href="#loglevel">LogLevel</a></code> directive.</p>
3086 <p>For requests that match a <code class="directive">LogLevelOverride</code>
3087 directive, per-directory specifications of
3088 <code class="directive"><a href="#loglevel">LogLevel</a></code> are ignored.</p>
3092 <pre class="prettyprint lang-config"> LogLevelOverride 192.0.2.0/24 ssl:trace6
3093 LogLevelOverride 192.0.2.7 ssl:trace8</pre>
3097 <code class="directive">LogLevelOverride</code> only affects
3098 log messages that are associated with the request or the connection.
3099 Log messages which are associated with the server are not affected.
3105 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
3108 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3109 <div class="directive-section"><h2><a name="MaxKeepAliveRequests" id="MaxKeepAliveRequests">MaxKeepAliveRequests</a> <a name="maxkeepaliverequests" id="maxkeepaliverequests">Directive</a></h2>
3110 <table class="directive">
3111 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of requests allowed on a persistent
3112 connection</td></tr>
3113 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxKeepAliveRequests <var>number</var></code></td></tr>
3114 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxKeepAliveRequests 100</code></td></tr>
3115 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3116 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3117 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3119 <p>The <code class="directive">MaxKeepAliveRequests</code> directive
3120 limits the number of requests allowed per connection when
3121 <code class="directive"><a href="#keepalive">KeepAlive</a></code> is on. If it is
3122 set to <code>0</code>, unlimited requests will be allowed. We
3123 recommend that this setting be kept to a high value for maximum
3124 server performance.</p>
3128 <pre class="prettyprint lang-config">MaxKeepAliveRequests 500</pre>
3132 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3133 <div class="directive-section"><h2><a name="MaxRangeOverlaps" id="MaxRangeOverlaps">MaxRangeOverlaps</a> <a name="maxrangeoverlaps" id="maxrangeoverlaps">Directive</a></h2>
3134 <table class="directive">
3135 <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
3137 <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>
3138 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeOverlaps 20</code></td></tr>
3139 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3140 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3141 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3142 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3144 <p>The <code class="directive">MaxRangeOverlaps</code> directive
3145 limits the number of overlapping HTTP ranges the server is willing to
3146 return to the client. If more overlapping ranges than permitted are requested,
3147 the complete resource is returned instead.</p>
3150 <dt><strong>default</strong></dt>
3151 <dd>Limits the number of overlapping ranges to a compile-time default of 20.</dd>
3153 <dt><strong>none</strong></dt>
3154 <dd>No overlapping Range headers are allowed.</dd>
3156 <dt><strong>unlimited</strong></dt>
3157 <dd>The server does not limit the number of overlapping ranges it is
3158 willing to satisfy.</dd>
3160 <dt><var>number-of-ranges</var></dt>
3161 <dd>A positive number representing the maximum number of overlapping ranges the
3162 server is willing to satisfy.</dd>
3166 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3167 <div class="directive-section"><h2><a name="MaxRangeReversals" id="MaxRangeReversals">MaxRangeReversals</a> <a name="maxrangereversals" id="maxrangereversals">Directive</a></h2>
3168 <table class="directive">
3169 <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
3171 <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>
3172 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeReversals 20</code></td></tr>
3173 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3174 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3175 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3176 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3178 <p>The <code class="directive">MaxRangeReversals</code> directive
3179 limits the number of HTTP Range reversals the server is willing to
3180 return to the client. If more ranges reversals than permitted are requested,
3181 the complete resource is returned instead.</p>
3184 <dt><strong>default</strong></dt>
3185 <dd>Limits the number of range reversals to a compile-time default of 20.</dd>
3187 <dt><strong>none</strong></dt>
3188 <dd>No Range reversals headers are allowed.</dd>
3190 <dt><strong>unlimited</strong></dt>
3191 <dd>The server does not limit the number of range reversals it is
3192 willing to satisfy.</dd>
3194 <dt><var>number-of-ranges</var></dt>
3195 <dd>A positive number representing the maximum number of range reversals the
3196 server is willing to satisfy.</dd>
3200 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3201 <div class="directive-section"><h2><a name="MaxRanges" id="MaxRanges">MaxRanges</a> <a name="maxranges" id="maxranges">Directive</a></h2>
3202 <table class="directive">
3203 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of ranges allowed before returning the complete
3205 <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>
3206 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRanges 200</code></td></tr>
3207 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3208 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3209 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3210 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3212 <p>The <code class="directive">MaxRanges</code> directive
3213 limits the number of HTTP ranges the server is willing to
3214 return to the client. If more ranges than permitted are requested,
3215 the complete resource is returned instead.</p>
3218 <dt><strong>default</strong></dt>
3219 <dd>Limits the number of ranges to a compile-time default of 200.</dd>
3221 <dt><strong>none</strong></dt>
3222 <dd>Range headers are ignored.</dd>
3224 <dt><strong>unlimited</strong></dt>
3225 <dd>The server does not limit the number of ranges it is
3226 willing to satisfy.</dd>
3228 <dt><var>number-of-ranges</var></dt>
3229 <dd>A positive number representing the maximum number of ranges the
3230 server is willing to satisfy.</dd>
3234 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3235 <div class="directive-section"><h2><a name="MergeTrailers" id="MergeTrailers">MergeTrailers</a> <a name="mergetrailers" id="mergetrailers">Directive</a></h2>
3236 <table class="directive">
3237 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines whether trailers are merged into headers</td></tr>
3238 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MergeTrailers [on|off]</code></td></tr>
3239 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MergeTrailers off</code></td></tr>
3240 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3241 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3242 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3243 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.4.11 and later</td></tr>
3245 <p>This directive controls whether HTTP trailers are copied into the
3246 internal representation of HTTP headers. This merging occurs when the
3247 request body has been completely consumed, long after most header
3248 processing would have a chance to examine or modify request headers.</p>
3249 <p>This option is provided for compatibility with releases prior to 2.4.11,
3250 where trailers were always merged.</p>
3253 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3254 <div class="directive-section"><h2><a name="Mutex" id="Mutex">Mutex</a> <a name="mutex" id="mutex">Directive</a></h2>
3255 <table class="directive">
3256 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures mutex mechanism and lock file directory for all
3257 or specified mutexes</td></tr>
3258 <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>
3259 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Mutex default</code></td></tr>
3260 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3261 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3262 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3263 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.4 and later</td></tr>
3265 <p>The <code class="directive">Mutex</code> directive sets the mechanism,
3266 and optionally the lock file location, that httpd and modules use
3267 to serialize access to resources. Specify <code>default</code> as
3268 the second argument to change the settings for all mutexes; specify
3269 a mutex name (see table below) as the second argument to override
3270 defaults only for that mutex.</p>
3272 <p>The <code class="directive">Mutex</code> directive is typically used in
3273 the following exceptional situations:</p>
3276 <li>change the mutex mechanism when the default mechanism selected
3277 by <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> has a functional or performance
3280 <li>change the directory used by file-based mutexes when the
3281 default directory does not support locking</li>
3284 <div class="note"><h3>Supported modules</h3>
3285 <p>This directive only configures mutexes which have been registered
3286 with the core server using the <code>ap_mutex_register()</code> API.
3287 All modules bundled with httpd support the <code class="directive">Mutex</code>
3288 directive, but third-party modules may not. Consult the documentation
3289 of the third-party module, which must indicate the mutex name(s) which
3290 can be configured if this directive is supported.</p>
3293 <p>The following mutex <em>mechanisms</em> are available:</p>
3295 <li><code>default | yes</code>
3296 <p>This selects the default locking implementation, as determined by
3297 <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a>. The default locking implementation can
3298 be displayed by running <code class="program"><a href="../programs/httpd.html">httpd</a></code> with the
3299 <code>-V</code> option.</p></li>
3301 <li><code>none | no</code>
3302 <p>This effectively disables the mutex, and is only allowed for a
3303 mutex if the module indicates that it is a valid choice. Consult the
3304 module documentation for more information.</p></li>
3306 <li><code>posixsem</code>
3307 <p>This is a mutex variant based on a Posix semaphore.</p>
3309 <div class="warning"><h3>Warning</h3>
3310 <p>The semaphore ownership is not recovered if a thread in the process
3311 holding the mutex segfaults, resulting in a hang of the web server.</p>
3315 <li><code>sysvsem</code>
3316 <p>This is a mutex variant based on a SystemV IPC semaphore.</p>
3318 <div class="warning"><h3>Warning</h3>
3319 <p>It is possible to "leak" SysV semaphores if processes crash
3320 before the semaphore is removed.</p>
3323 <div class="warning"><h3>Security</h3>
3324 <p>The semaphore API allows for a denial of service attack by any
3325 CGIs running under the same uid as the webserver (<em>i.e.</em>,
3326 all CGIs, unless you use something like <code class="program"><a href="../programs/suexec.html">suexec</a></code>
3327 or <code>cgiwrapper</code>).</p>
3331 <li><code>sem</code>
3332 <p>This selects the "best" available semaphore implementation, choosing
3333 between Posix and SystemV IPC semaphores, in that order.</p></li>
3335 <li><code>pthread</code>
3336 <p>This is a mutex variant based on cross-process Posix thread
3339 <div class="warning"><h3>Warning</h3>
3340 <p>On most systems, if a child process terminates abnormally while
3341 holding a mutex that uses this implementation, the server will deadlock
3342 and stop responding to requests. When this occurs, the server will
3343 require a manual restart to recover.</p>
3344 <p>Solaris and Linux are notable exceptions as they provide a mechanism which
3345 usually allows the mutex to be recovered after a child process
3346 terminates abnormally while holding a mutex.</p>
3347 <p>If your system is POSIX compliant or if it implements the
3348 <code>pthread_mutexattr_setrobust_np()</code> function, you may be able
3349 to use the <code>pthread</code> option safely.</p>
3353 <li><code>fcntl:/path/to/mutex</code>
3354 <p>This is a mutex variant where a physical (lock-)file and the
3355 <code>fcntl()</code> function are used as the mutex.</p>
3357 <div class="warning"><h3>Warning</h3>
3358 <p>When multiple mutexes based on this mechanism are used within
3359 multi-threaded, multi-process environments, deadlock errors (EDEADLK)
3360 can be reported for valid mutex operations if <code>fcntl()</code>
3361 is not thread-aware, such as on Solaris.</p>
3365 <li><code>flock:/path/to/mutex</code>
3366 <p>This is similar to the <code>fcntl:/path/to/mutex</code> method
3367 with the exception that the <code>flock()</code> function is used to
3368 provide file locking.</p></li>
3370 <li><code>file:/path/to/mutex</code>
3371 <p>This selects the "best" available file locking implementation,
3372 choosing between <code>fcntl</code> and <code>flock</code>, in that
3376 <p>Most mechanisms are only available on selected platforms, where the
3377 underlying platform and <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> support it. Mechanisms
3378 which aren't available on all platforms are <em>posixsem</em>,
3379 <em>sysvsem</em>, <em>sem</em>, <em>pthread</em>, <em>fcntl</em>,
3380 <em>flock</em>, and <em>file</em>.</p>
3382 <p>With the file-based mechanisms <em>fcntl</em> and <em>flock</em>,
3383 the path, if provided, is a directory where the lock file will be created.
3384 The default directory is httpd's run-time file directory,
3385 <code class="directive"><a href="#defaultruntimedir">DefaultRuntimeDir</a></code>. If a relative
3386 path is provided, it is relative to
3387 <code class="directive"><a href="#defaultruntimedir">DefaultRuntimeDir</a></code>. Always use a local
3388 disk filesystem for <code>/path/to/mutex</code> and never a directory residing
3389 on a NFS- or AFS-filesystem. The basename of the file will be the mutex
3390 type, an optional instance string provided by the module, and unless the
3391 <code>OmitPID</code> keyword is specified, the process id of the httpd
3392 parent process will be appended to make the file name unique, avoiding
3393 conflicts when multiple httpd instances share a lock file directory. For
3394 example, if the mutex name is <code>mpm-accept</code> and the lock file
3395 directory is <code>/var/httpd/locks</code>, the lock file name for the
3396 httpd instance with parent process id 12345 would be
3397 <code>/var/httpd/locks/mpm-accept.12345</code>.</p>
3399 <div class="warning"><h3>Security</h3>
3400 <p>It is best to <em>avoid</em> putting mutex files in a world-writable
3401 directory such as <code>/var/tmp</code> because someone could create
3402 a denial of service attack and prevent the server from starting by
3403 creating a lockfile with the same name as the one the server will try
3407 <p>The following table documents the names of mutexes used by httpd
3408 and bundled modules.</p>
3410 <table class="bordered"><tr class="header">
3413 <th>Protected resource</th>
3416 <td><code>mpm-accept</code></td>
3417 <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>
3418 <td>incoming connections, to avoid the thundering herd problem;
3419 for more information, refer to the
3420 <a href="../misc/perf-tuning.html">performance tuning</a>
3424 <td><code>authdigest-client</code></td>
3425 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3426 <td>client list in shared memory</td>
3429 <td><code>authdigest-opaque</code></td>
3430 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3431 <td>counter in shared memory</td>
3434 <td><code>ldap-cache</code></td>
3435 <td><code class="module"><a href="../mod/mod_ldap.html">mod_ldap</a></code></td>
3436 <td>LDAP result cache</td>
3439 <td><code>rewrite-map</code></td>
3440 <td><code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code></td>
3441 <td>communication with external mapping programs, to avoid
3442 intermixed I/O from multiple requests</td>
3445 <td><code>ssl-cache</code></td>
3446 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3447 <td>SSL session cache</td>
3450 <td><code>ssl-stapling</code></td>
3451 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3452 <td>OCSP stapling response cache</td>
3455 <td><code>watchdog-callback</code></td>
3456 <td><code class="module"><a href="../mod/mod_watchdog.html">mod_watchdog</a></code></td>
3457 <td>callback function of a particular client module</td>
3461 <p>The <code>OmitPID</code> keyword suppresses the addition of the httpd
3462 parent process id from the lock file name.</p>
3464 <p>In the following example, the mutex mechanism for the MPM accept
3465 mutex will be changed from the compiled-in default to <code>fcntl</code>,
3466 with the associated lock file created in directory
3467 <code>/var/httpd/locks</code>. The mutex mechanism for all other mutexes
3468 will be changed from the compiled-in default to <code>sysvsem</code>.</p>
3470 <pre class="prettyprint lang-config">Mutex sysvsem default
3471 Mutex fcntl:/var/httpd/locks mpm-accept</pre>
3475 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3476 <div class="directive-section"><h2><a name="NameVirtualHost" id="NameVirtualHost">NameVirtualHost</a> <a name="namevirtualhost" id="namevirtualhost">Directive</a></h2>
3477 <table class="directive">
3478 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>DEPRECATED: Designates an IP address for name-virtual
3480 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NameVirtualHost <var>addr</var>[:<var>port</var>]</code></td></tr>
3481 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3482 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3483 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3486 <p>Prior to 2.3.11, <code class="directive">NameVirtualHost</code> was required
3487 to instruct the server that a particular IP address and port combination
3488 was usable as a name-based virtual host. In 2.3.11 and later,
3489 any time an IP address and port combination is used in multiple virtual
3490 hosts, name-based virtual hosting is automatically enabled for that address.</p>
3492 <p>This directive currently has no effect.</p>
3496 <li><a href="../vhosts/">Virtual Hosts
3497 documentation</a></li>
3500 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3501 <div class="directive-section"><h2><a name="Options" id="Options">Options</a> <a name="options" id="options">Directive</a></h2>
3502 <table class="directive">
3503 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures what features are available in a particular
3505 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Options
3506 [+|-]<var>option</var> [[+|-]<var>option</var>] ...</code></td></tr>
3507 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Options FollowSymlinks</code></td></tr>
3508 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3509 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
3510 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3511 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3512 <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>
3514 <p>The <code class="directive">Options</code> directive controls which
3515 server features are available in a particular directory.</p>
3517 <p><var>option</var> can be set to <code>None</code>, in which
3518 case none of the extra features are enabled, or one or more of
3522 <dt><code>All</code></dt>
3524 <dd>All options except for <code>MultiViews</code>.</dd>
3526 <dt><code>ExecCGI</code></dt>
3529 Execution of CGI scripts using <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>
3532 <dt><code>FollowSymLinks</code></dt>
3535 The server will follow symbolic links in this directory. This is
3536 the default setting.
3538 <p>Even though the server follows the symlink it does <em>not</em>
3539 change the pathname used to match against <code class="directive"><a href="#directory"><Directory></a></code> sections.</p>
3541 <p>The <code>FollowSymLinks</code> and
3542 <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
3543 <code>.htaccess</code> files.</p>
3545 <p>Omitting this option should not be considered a security restriction,
3546 since symlink testing is subject to race conditions that make it
3550 <dt><code>Includes</code></dt>
3553 Server-side includes provided by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
3556 <dt><code>IncludesNOEXEC</code></dt>
3560 Server-side includes are permitted, but the <code>#exec
3561 cmd</code> and <code>#exec cgi</code> are disabled. It is still
3562 possible to <code>#include virtual</code> CGI scripts from
3563 <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>ed
3566 <dt><code>Indexes</code></dt>
3569 If a URL which maps to a directory is requested and there
3570 is no <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
3571 (<em>e.g.</em>, <code>index.html</code>) in that directory, then
3572 <code class="module"><a href="../mod/mod_autoindex.html">mod_autoindex</a></code> will return a formatted listing
3573 of the directory.</dd>
3575 <dt><code>MultiViews</code></dt>
3578 <a href="../content-negotiation.html">Content negotiated</a>
3579 "MultiViews" are allowed using
3580 <code class="module"><a href="../mod/mod_negotiation.html">mod_negotiation</a></code>.
3581 <div class="note"><h3>Note</h3> <p>This option gets ignored if set
3582 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>
3583 needs real resources to compare against and evaluate from.</p></div>
3586 <dt><code>SymLinksIfOwnerMatch</code></dt>
3588 <dd>The server will only follow symbolic links for which the
3589 target file or directory is owned by the same user id as the
3592 <div class="note"><h3>Note</h3>
3593 <p>The <code>FollowSymLinks</code> and
3594 <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
3595 <code>.htaccess</code> files.</p>
3597 <p>This option should not be considered a security restriction,
3598 since symlink testing is subject to race conditions that make it
3603 <p>Normally, if multiple <code class="directive">Options</code> could
3604 apply to a directory, then the most specific one is used and
3605 others are ignored; the options are not merged. (See <a href="../sections.html#mergin">how sections are merged</a>.)
3606 However if <em>all</em> the options on the
3607 <code class="directive">Options</code> directive are preceded by a
3608 <code>+</code> or <code>-</code> symbol, the options are
3609 merged. Any options preceded by a <code>+</code> are added to the
3610 options currently in force, and any options preceded by a
3611 <code>-</code> are removed from the options currently in
3614 <div class="note"><h3>Note</h3>
3615 <p>Mixing <code class="directive">Options</code> with a <code>+</code> or
3616 <code>-</code> with those without is not valid syntax and will be
3617 rejected during server startup by the syntax check with an abort.</p>
3620 <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>
3622 <pre class="prettyprint lang-config"><Directory "/web/docs">
3623 Options Indexes FollowSymLinks
3626 <Directory "/web/docs/spec">
3628 </Directory></pre>
3631 <p>then only <code>Includes</code> will be set for the
3632 <code>/web/docs/spec</code> directory. However if the second
3633 <code class="directive">Options</code> directive uses the <code>+</code> and
3634 <code>-</code> symbols:</p>
3636 <pre class="prettyprint lang-config"><Directory "/web/docs">
3637 Options Indexes FollowSymLinks
3640 <Directory "/web/docs/spec">
3641 Options +Includes -Indexes
3642 </Directory></pre>
3645 <p>then the options <code>FollowSymLinks</code> and
3646 <code>Includes</code> are set for the <code>/web/docs/spec</code>
3649 <div class="note"><h3>Note</h3>
3650 <p>Using <code>-IncludesNOEXEC</code> or
3651 <code>-Includes</code> disables server-side includes completely
3652 regardless of the previous setting.</p>
3655 <p>The default in the absence of any other settings is
3656 <code>FollowSymlinks</code>.</p>
3659 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3660 <div class="directive-section"><h2><a name="Protocol" id="Protocol">Protocol</a> <a name="protocol" id="protocol">Directive</a></h2>
3661 <table class="directive">
3662 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Protocol for a listening socket</td></tr>
3663 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Protocol <var>protocol</var></code></td></tr>
3664 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3665 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3666 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3667 <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>
3669 <p>This directive specifies the protocol used for a specific listening socket.
3670 The protocol is used to determine which module should handle a request and
3671 to apply protocol specific optimizations with the <code class="directive">AcceptFilter</code>
3674 <p>You only need to set the protocol if you are running on non-standard ports;
3675 otherwise, <code>http</code> is assumed for port 80 and <code>https</code>
3678 <p>For example, if you are running <code>https</code> on a non-standard port,
3679 specify the protocol explicitly:</p>
3681 <pre class="prettyprint lang-config">Protocol https</pre>
3684 <p>You can also specify the protocol using the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code> directive.</p>
3688 <li><code class="directive"><a href="#acceptfilter">AcceptFilter</a></code></li>
3689 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
3692 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3693 <div class="directive-section"><h2><a name="Protocols" id="Protocols">Protocols</a> <a name="protocols" id="protocols">Directive</a></h2>
3694 <table class="directive">
3695 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Protocols available for a server/virtual host</td></tr>
3696 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Protocols <var>protocol</var> ...</code></td></tr>
3697 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Protocols http/1.1</code></td></tr>
3698 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3699 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3700 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3701 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Only available from Apache 2.4.17 and later.</td></tr>
3703 <p>This directive specifies the list of protocols supported for a
3704 server/virtual host. The list determines the allowed protocols
3705 a client may negotiate for this server/host.</p>
3707 <p>You need to set protocols if you want to extend the available
3708 protocols for a server/host. By default, only the http/1.1 protocol
3709 (which includes the compatibility with 1.0 and 0.9 clients) is
3712 <p>For example, if you want to support HTTP/2 for a server with TLS,
3715 <pre class="prettyprint lang-config">Protocols h2 http/1.1</pre>
3718 <p>Valid protocols are <code>http/1.1</code> for http and https connections,
3719 <code>h2</code> on https connections and <code>h2c</code> for http
3720 connections. Modules may enable more protocols.</p>
3722 <p>It is safe to specify protocols that are unavailable/disabled. Such
3723 protocol names will simply be ignored.</p>
3725 <p>Protocols specified in base servers are inherited for virtual hosts
3726 only if the virtual host has no own Protocols directive. Or, the other
3727 way around, Protocols directives in virtual hosts replace any
3728 such directive in the base server.
3734 <li><code class="directive"><a href="#protocolshonororder">ProtocolsHonorOrder</a></code></li>
3737 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3738 <div class="directive-section"><h2><a name="ProtocolsHonorOrder" id="ProtocolsHonorOrder">ProtocolsHonorOrder</a> <a name="protocolshonororder" id="protocolshonororder">Directive</a></h2>
3739 <table class="directive">
3740 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines if order of Protocols determines precedence during negotiation</td></tr>
3741 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProtocolsHonorOrder On|Off</code></td></tr>
3742 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProtocolsHonorOrder On</code></td></tr>
3743 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3744 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3745 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3746 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Only available from Apache 2.4.17 and later.</td></tr>
3748 <p>This directive specifies if the server should honor the order in which
3749 the <code class="directive">Protocols</code> directive lists protocols.</p>
3751 <p>If configured Off, the client supplied list order of protocols has
3752 precedence over the order in the server configuration.</p>
3754 <p>With <code class="directive">ProtocolsHonorOrder</code> set to <code>on</code>
3755 (default), the client ordering does not matter and only the ordering
3756 in the server settings influences the outcome of the protocol
3762 <li><code class="directive"><a href="#protocols">Protocols</a></code></li>
3765 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3766 <div class="directive-section"><h2><a name="QualifyRedirectURL" id="QualifyRedirectURL">QualifyRedirectURL</a> <a name="qualifyredirecturl" id="qualifyredirecturl">Directive</a></h2>
3767 <table class="directive">
3768 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Controls whether the REDIRECT_URL environent variable is
3769 fully qualified</td></tr>
3770 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>QualifyRedirectURL ON|OFF</code></td></tr>
3771 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>QualifyRedirectURL OFF</code></td></tr>
3772 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3773 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3774 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3775 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3776 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Directive supported in 2.4.18 and later. 2.4.17 acted
3777 as if 'QualifyRedirectURL ON' was configured.</td></tr>
3779 <p>This directive controls whether the server will ensure that the
3780 REDIRECT_URL environment variable is fully qualified. By default,
3781 the variable contains the verbatim URL requested by the client,
3782 such as "/index.html". With <code class="directive"><a href="#qualifyredirecturl on">QualifyRedirectURL ON</a></code>, the same request would result in a
3783 value such as "http://www.example.com/index.html".</p>
3784 <p>Even without this directive set, when a request is issued against a
3785 fully qualified URL, REDIRECT_URL will remain fully qualified.
3789 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3790 <div class="directive-section"><h2><a name="RegisterHttpMethod" id="RegisterHttpMethod">RegisterHttpMethod</a> <a name="registerhttpmethod" id="registerhttpmethod">Directive</a></h2>
3791 <table class="directive">
3792 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Register non-standard HTTP methods</td></tr>
3793 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>RegisterHttpMethod <var>method</var> [<var>method</var> [...]]</code></td></tr>
3794 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3795 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3796 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3798 <p>HTTP Methods that are not conforming to the relvant RFCs are normally
3799 rejected by request processing in Apache HTTPD. To avoid this, modules
3800 can register non-standard HTTP methods they support.
3801 The <code class="directive">RegisterHttpMethod</code> allows to register such
3802 methods manually. This can be useful if such methods are forwarded
3803 for external processing, e.g. to a CGI script.</p>
3806 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3807 <div class="directive-section"><h2><a name="RLimitCPU" id="RLimitCPU">RLimitCPU</a> <a name="rlimitcpu" id="rlimitcpu">Directive</a></h2>
3808 <table class="directive">
3809 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the CPU consumption of processes launched
3810 by Apache httpd children</td></tr>
3811 <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>
3812 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3813 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3814 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3815 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3816 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3818 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3819 resource limit for all processes and the second parameter sets
3820 the maximum resource limit. Either parameter can be a number,
3821 or <code>max</code> to indicate to the server that the limit should
3822 be set to the maximum allowed by the operating system
3823 configuration. Raising the maximum resource limit requires that
3824 the server is running as <code>root</code> or in the initial startup
3827 <p>This applies to processes forked from Apache httpd children
3828 servicing requests, not the Apache httpd children themselves. This
3829 includes CGI scripts and SSI exec commands, but not any
3830 processes forked from the Apache httpd parent, such as piped
3833 <p>CPU resource limits are expressed in seconds per
3838 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3839 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3842 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3843 <div class="directive-section"><h2><a name="RLimitMEM" id="RLimitMEM">RLimitMEM</a> <a name="rlimitmem" id="rlimitmem">Directive</a></h2>
3844 <table class="directive">
3845 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the memory consumption of processes launched
3846 by Apache httpd children</td></tr>
3847 <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>
3848 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3849 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3850 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</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>
3854 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3855 resource limit for all processes and the second parameter sets
3856 the maximum resource limit. Either parameter can be a number,
3857 or <code>max</code> to indicate to the server that the limit should
3858 be set to the maximum allowed by the operating system
3859 configuration. Raising the maximum resource limit requires that
3860 the server is running as <code>root</code> or in the initial startup
3863 <p>This applies to processes forked from Apache httpd children
3864 servicing requests, not the Apache httpd children themselves. This
3865 includes CGI scripts and SSI exec commands, but not any
3866 processes forked from the Apache httpd parent, such as piped
3869 <p>Memory resource limits are expressed in bytes per
3874 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3875 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3878 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3879 <div class="directive-section"><h2><a name="RLimitNPROC" id="RLimitNPROC">RLimitNPROC</a> <a name="rlimitnproc" id="rlimitnproc">Directive</a></h2>
3880 <table class="directive">
3881 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of processes that can be launched by
3882 processes launched by Apache httpd children</td></tr>
3883 <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>
3884 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3885 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3886 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3887 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3888 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3890 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3891 resource limit for all processes, and the second parameter sets
3892 the maximum resource limit. Either parameter can be a number,
3893 or <code>max</code> to indicate to the server that the limit
3894 should be set to the maximum allowed by the operating system
3895 configuration. Raising the maximum resource limit requires that
3896 the server is running as <code>root</code> or in the initial startup
3899 <p>This applies to processes forked from Apache httpd children
3900 servicing requests, not the Apache httpd children themselves. This
3901 includes CGI scripts and SSI exec commands, but not any
3902 processes forked from the Apache httpd parent, such as piped
3905 <p>Process limits control the number of processes per user.</p>
3907 <div class="note"><h3>Note</h3>
3908 <p>If CGI processes are <strong>not</strong> running
3909 under user ids other than the web server user id, this directive
3910 will limit the number of processes that the server itself can
3911 create. Evidence of this situation will be indicated by
3912 <strong><code>cannot fork</code></strong> messages in the
3913 <code>error_log</code>.</p>
3918 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3919 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3922 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3923 <div class="directive-section"><h2><a name="ScriptInterpreterSource" id="ScriptInterpreterSource">ScriptInterpreterSource</a> <a name="scriptinterpretersource" id="scriptinterpretersource">Directive</a></h2>
3924 <table class="directive">
3925 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
3927 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ScriptInterpreterSource Registry|Registry-Strict|Script</code></td></tr>
3928 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ScriptInterpreterSource Script</code></td></tr>
3929 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3930 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3931 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3932 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3933 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Win32 only.</td></tr>
3935 <p>This directive is used to control how Apache httpd finds the
3936 interpreter used to run CGI scripts. The default setting is
3937 <code>Script</code>. This causes Apache httpd to use the interpreter pointed to
3938 by the shebang line (first line, starting with <code>#!</code>) in the
3939 script. On Win32 systems this line usually looks like:</p>
3941 <pre class="prettyprint lang-perl">#!C:/Perl/bin/perl.exe</pre>
3944 <p>or, if <code>perl</code> is in the <code>PATH</code>, simply:</p>
3946 <pre class="prettyprint lang-perl">#!perl</pre>
3949 <p>Setting <code>ScriptInterpreterSource Registry</code> will
3950 cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
3951 searched using the script file extension (e.g., <code>.pl</code>) as a
3952 search key. The command defined by the registry subkey
3953 <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
3954 <code>Shell\Open\Command</code> is used to open the script file. If the
3955 registry keys cannot be found, Apache httpd falls back to the behavior of the
3956 <code>Script</code> option.</p>
3958 <div class="warning"><h3>Security</h3>
3959 <p>Be careful when using <code>ScriptInterpreterSource
3960 Registry</code> with <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>'ed directories, because
3961 Apache httpd will try to execute <strong>every</strong> file within this
3962 directory. The <code>Registry</code> setting may cause undesired
3963 program calls on files which are typically not executed. For
3964 example, the default open command on <code>.htm</code> files on
3965 most Windows systems will execute Microsoft Internet Explorer, so
3966 any HTTP request for an <code>.htm</code> file existing within the
3967 script directory would start the browser in the background on the
3968 server. This is a good way to crash your system within a minute or
3972 <p>The option <code>Registry-Strict</code> which is new in Apache HTTP Server
3973 2.0 does the same thing as <code>Registry</code> but uses only the
3974 subkey <code>Shell\ExecCGI\Command</code>. The
3975 <code>ExecCGI</code> key is not a common one. It must be
3976 configured manually in the windows registry and hence prevents
3977 accidental program calls on your system.</p>
3980 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3981 <div class="directive-section"><h2><a name="SeeRequestTail" id="SeeRequestTail">SeeRequestTail</a> <a name="seerequesttail" id="seerequesttail">Directive</a></h2>
3982 <table class="directive">
3983 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine if mod_status displays the first 63 characters
3984 of a request or the last 63, assuming the request itself is greater than
3986 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SeeRequestTail On|Off</code></td></tr>
3987 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SeeRequestTail Off</code></td></tr>
3988 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3989 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3990 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3992 <p>mod_status with <code>ExtendedStatus On</code>
3993 displays the actual request being handled.
3994 For historical purposes, only 63 characters of the request
3995 are actually stored for display purposes. This directive
3996 controls whether the 1st 63 characters are stored (the previous
3997 behavior and the default) or if the last 63 characters are. This
3998 is only applicable, of course, if the length of the request is
3999 64 characters or greater.</p>
4001 <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:
4004 <table class="bordered">
4006 <th>Off (default)</th>
4007 <td>GET /disk1/storage/apache/htdocs/images/imagestore1/food/apples</td>
4011 <td>orage/apache/htdocs/images/imagestore1/food/apples.jpg HTTP/1.1</td>
4017 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4018 <div class="directive-section"><h2><a name="ServerAdmin" id="ServerAdmin">ServerAdmin</a> <a name="serveradmin" id="serveradmin">Directive</a></h2>
4019 <table class="directive">
4020 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Email address that the server includes in error
4021 messages sent to the client</td></tr>
4022 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAdmin <var>email-address</var>|<var>URL</var></code></td></tr>
4023 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4024 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4025 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4027 <p>The <code class="directive">ServerAdmin</code> sets the contact address
4028 that the server includes in any error messages it returns to the
4029 client. If the <code>httpd</code> doesn't recognize the supplied argument
4031 assumes, that it's an <var>email-address</var> and prepends it with
4032 <code>mailto:</code> in hyperlink targets. However, it's recommended to
4033 actually use an email address, since there are a lot of CGI scripts that
4034 make that assumption. If you want to use an URL, it should point to another
4035 server under your control. Otherwise users may not be able to contact you in
4038 <p>It may be worth setting up a dedicated address for this, e.g.</p>
4040 <pre class="prettyprint lang-config">ServerAdmin www-admin@foo.example.com</pre>
4042 <p>as users do not always mention that they are talking about the
4046 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4047 <div class="directive-section"><h2><a name="ServerAlias" id="ServerAlias">ServerAlias</a> <a name="serveralias" id="serveralias">Directive</a></h2>
4048 <table class="directive">
4049 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Alternate names for a host used when matching requests
4050 to name-virtual hosts</td></tr>
4051 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</code></td></tr>
4052 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
4053 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4054 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4056 <p>The <code class="directive">ServerAlias</code> directive sets the
4057 alternate names for a host, for use with <a href="../vhosts/name-based.html">name-based virtual hosts</a>. The
4058 <code class="directive">ServerAlias</code> may include wildcards, if appropriate.</p>
4060 <pre class="prettyprint lang-config"><VirtualHost *:80>
4061 ServerName server.example.com
4062 ServerAlias server server2.example.com server2
4063 ServerAlias *.example.com
4064 UseCanonicalName Off
4066 </VirtualHost></pre>
4069 <p>Name-based virtual hosts for the best-matching set of <code class="directive"><a href="#virtualhost"><virtualhost></a></code>s are processed
4070 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
4071 (nor for ServerName vs. ServerAlias). </p>
4073 <p>The complete list of names in the <code class="directive">VirtualHost</code>
4074 directive are treated just like a (non wildcard)
4075 <code class="directive">ServerAlias</code>.</p>
4080 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
4081 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4084 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4085 <div class="directive-section"><h2><a name="ServerName" id="ServerName">ServerName</a> <a name="servername" id="servername">Directive</a></h2>
4086 <table class="directive">
4087 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hostname and port that the server uses to identify
4089 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerName [<var>scheme</var>://]<var>fully-qualified-domain-name</var>[:<var>port</var>]</code></td></tr>
4090 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4091 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4092 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4094 <p>The <code class="directive">ServerName</code> directive sets the
4095 request scheme, hostname and
4096 port that the server uses to identify itself. This is used when
4097 creating redirection URLs.</p>
4099 <p>Additionally, <code class="directive">ServerName</code> is used (possibly
4100 in conjunction with <code class="directive">ServerAlias</code>) to uniquely
4101 identify a virtual host, when using <a href="../vhosts/name-based.html">name-based virtual hosts</a>.</p>
4103 <p>For example, if the name of the
4104 machine hosting the web server is <code>simple.example.com</code>,
4105 but the machine also has the DNS alias <code>www.example.com</code>
4106 and you wish the web server to be so identified, the following
4107 directive should be used:</p>
4109 <pre class="prettyprint lang-config">ServerName www.example.com</pre>
4112 <p>The <code class="directive">ServerName</code> directive
4113 may appear anywhere within the definition of a server. However,
4114 each appearance overrides the previous appearance (within that
4117 <p>If no <code class="directive">ServerName</code> is specified, then the
4118 server attempts to deduce the client visible hostname by performing a
4119 reverse lookup on an IP address of the systems hostname.</p>
4121 <p>If no port is specified in the
4122 <code class="directive">ServerName</code>, then the server will use the
4123 port from the incoming request. For optimal reliability and
4124 predictability, you should specify an explicit hostname and port
4125 using the <code class="directive">ServerName</code> directive.</p>
4127 <p>If you are using <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
4128 the <code class="directive">ServerName</code> inside a
4129 <code class="directive"><a href="#virtualhost"><VirtualHost></a></code>
4130 section specifies what hostname must appear in the request's
4131 <code>Host:</code> header to match this virtual host.</p>
4133 <p>Sometimes, the server runs behind a device that processes SSL,
4134 such as a reverse proxy, load balancer or SSL offload
4135 appliance. When this is the case, specify the
4136 <code>https://</code> scheme and the port number to which the
4137 clients connect in the <code class="directive">ServerName</code> directive
4138 to make sure that the server generates the correct
4139 self-referential URLs.
4142 <p>See the description of the
4143 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> and
4144 <code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code> directives for
4145 settings which determine whether self-referential URLs (e.g., by the
4146 <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> module) will refer to the
4147 specified port, or to the port number given in the client's request.
4150 <div class="warning">
4151 <p>Failure to set <code class="directive">ServerName</code> to a name that
4152 your server can resolve to an IP address will result in a startup
4153 warning. <code>httpd</code> will then use whatever hostname it can
4154 determine, using the system's <code>hostname</code> command. This
4155 will almost never be the hostname you actually want.</p>
4156 <div class="example"><p><code>
4157 httpd: Could not reliably determine the server's fully qualified domain name, using rocinante.local for ServerName
4164 <li><a href="../dns-caveats.html">Issues Regarding DNS and
4165 Apache HTTP Server</a></li>
4166 <li><a href="../vhosts/">Apache HTTP Server virtual host
4167 documentation</a></li>
4168 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
4169 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
4170 <li><code class="directive"><a href="#serveralias">ServerAlias</a></code></li>
4173 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4174 <div class="directive-section"><h2><a name="ServerPath" id="ServerPath">ServerPath</a> <a name="serverpath" id="serverpath">Directive</a></h2>
4175 <table class="directive">
4176 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Legacy URL pathname for a name-based virtual host that
4177 is accessed by an incompatible browser</td></tr>
4178 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerPath <var>URL-path</var></code></td></tr>
4179 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
4180 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4181 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4183 <p>The <code class="directive">ServerPath</code> directive sets the legacy
4184 URL pathname for a host, for use with <a href="../vhosts/">name-based virtual hosts</a>.</p>
4188 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4191 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4192 <div class="directive-section"><h2><a name="ServerRoot" id="ServerRoot">ServerRoot</a> <a name="serverroot" id="serverroot">Directive</a></h2>
4193 <table class="directive">
4194 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server installation</td></tr>
4195 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerRoot <var>directory-path</var></code></td></tr>
4196 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerRoot /usr/local/apache</code></td></tr>
4197 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4198 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4199 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4201 <p>The <code class="directive">ServerRoot</code> directive sets the
4202 directory in which the server lives. Typically it will contain the
4203 subdirectories <code>conf/</code> and <code>logs/</code>. Relative
4204 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
4205 relative to this directory.</p>
4207 <pre class="prettyprint lang-config">ServerRoot "/home/httpd"</pre>
4210 <p>The default location of <code class="directive">ServerRoot</code> may be
4211 modified by using the <code>--prefix</code> argument to
4212 <a href="../programs/configure.html"><code>configure</code></a>, and
4213 most third-party distributions of the server have a different
4214 default location from the one listed above.</p>
4219 <li><a href="../invoking.html">the <code>-d</code>
4220 option to <code>httpd</code></a></li>
4221 <li><a href="../misc/security_tips.html#serverroot">the
4222 security tips</a> for information on how to properly set
4223 permissions on the <code class="directive">ServerRoot</code></li>
4226 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4227 <div class="directive-section"><h2><a name="ServerSignature" id="ServerSignature">ServerSignature</a> <a name="serversignature" id="serversignature">Directive</a></h2>
4228 <table class="directive">
4229 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the footer on server-generated documents</td></tr>
4230 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerSignature On|Off|EMail</code></td></tr>
4231 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerSignature Off</code></td></tr>
4232 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4233 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
4234 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4235 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4237 <p>The <code class="directive">ServerSignature</code> directive allows the
4238 configuration of a trailing footer line under server-generated
4239 documents (error messages, <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> ftp directory
4240 listings, <code class="module"><a href="../mod/mod_info.html">mod_info</a></code> output, ...). The reason why you
4241 would want to enable such a footer line is that in a chain of proxies,
4242 the user often has no possibility to tell which of the chained servers
4243 actually produced a returned error message.</p>
4245 <p>The <code>Off</code>
4246 setting, which is the default, suppresses the footer line (and is
4247 therefore compatible with the behavior of Apache-1.2 and
4248 below). The <code>On</code> setting simply adds a line with the
4249 server version number and <code class="directive"><a href="#servername">ServerName</a></code> of the serving virtual host,
4250 and the <code>EMail</code> setting additionally creates a
4251 "mailto:" reference to the <code class="directive"><a href="#serveradmin">ServerAdmin</a></code> of the referenced
4254 <p>After version 2.0.44, the details of the server version number
4255 presented are controlled by the <code class="directive"><a href="#servertokens">ServerTokens</a></code> directive.</p>
4259 <li><code class="directive"><a href="#servertokens">ServerTokens</a></code></li>
4262 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4263 <div class="directive-section"><h2><a name="ServerTokens" id="ServerTokens">ServerTokens</a> <a name="servertokens" id="servertokens">Directive</a></h2>
4264 <table class="directive">
4265 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the <code>Server</code> HTTP response
4267 <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>
4268 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerTokens Full</code></td></tr>
4269 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4270 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4271 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4273 <p>This directive controls whether <code>Server</code> response
4274 header field which is sent back to clients includes a
4275 description of the generic OS-type of the server as well as
4276 information about compiled-in modules.</p>
4279 <dt><code>ServerTokens Full</code> (or not specified)</dt>
4281 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4282 (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
4284 <dt><code>ServerTokens Prod[uctOnly]</code></dt>
4286 <dd>Server sends (<em>e.g.</em>): <code>Server:
4289 <dt><code>ServerTokens Major</code></dt>
4291 <dd>Server sends (<em>e.g.</em>): <code>Server:
4292 Apache/2</code></dd>
4294 <dt><code>ServerTokens Minor</code></dt>
4296 <dd>Server sends (<em>e.g.</em>): <code>Server:
4297 Apache/2.4</code></dd>
4299 <dt><code>ServerTokens Min[imal]</code></dt>
4301 <dd>Server sends (<em>e.g.</em>): <code>Server:
4302 Apache/2.4.2</code></dd>
4304 <dt><code>ServerTokens OS</code></dt>
4306 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4311 <p>This setting applies to the entire server, and cannot be
4312 enabled or disabled on a virtualhost-by-virtualhost basis.</p>
4314 <p>After version 2.0.44, this directive also controls the
4315 information presented by the <code class="directive"><a href="#serversignature">ServerSignature</a></code> directive.</p>
4317 <div class="note">Setting <code class="directive">ServerTokens</code> to less than
4318 <code>minimal</code> is not recommended because it makes it more
4319 difficult to debug interoperational problems. Also note that
4320 disabling the Server: header does nothing at all to make your
4321 server more secure. The idea of "security through obscurity"
4322 is a myth and leads to a false sense of safety.</div>
4326 <li><code class="directive"><a href="#serversignature">ServerSignature</a></code></li>
4329 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4330 <div class="directive-section"><h2><a name="SetHandler" id="SetHandler">SetHandler</a> <a name="sethandler" id="sethandler">Directive</a></h2>
4331 <table class="directive">
4332 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be processed by a
4334 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetHandler <var>handler-name</var>|None</code></td></tr>
4335 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4336 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</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>When placed into an <code>.htaccess</code> file or a
4341 <code class="directive"><a href="#directory"><Directory></a></code> or
4342 <code class="directive"><a href="#location"><Location></a></code>
4343 section, this directive forces all matching files to be parsed
4344 through the <a href="../handler.html">handler</a> given by
4345 <var>handler-name</var>. For example, if you had a directory you
4346 wanted to be parsed entirely as imagemap rule files, regardless
4347 of extension, you might put the following into an
4348 <code>.htaccess</code> file in that directory:</p>
4350 <pre class="prettyprint lang-config">SetHandler imap-file</pre>
4353 <p>Another example: if you wanted to have the server display a
4354 status report whenever a URL of
4355 <code>http://servername/status</code> was called, you might put
4356 the following into <code>httpd.conf</code>:</p>
4358 <pre class="prettyprint lang-config"><Location "/status">
4359 SetHandler server-status
4360 </Location></pre>
4363 <p>You could also use this directive to configure a particular
4364 handler for files with a particular file extension. For example:</p>
4366 <pre class="prettyprint lang-config"><FilesMatch "\.php$">
4367 SetHandler application/x-httpd-php
4368 </FilesMatch></pre>
4371 <p>You can override an earlier defined <code class="directive">SetHandler</code>
4372 directive by using the value <code>None</code>.</p>
4374 <div class="note"><h3>Note</h3>
4375 <p>Because <code class="directive">SetHandler</code> overrides default handlers,
4376 normal behavior such as handling of URLs ending in a slash (/) as
4377 directories or index files is suppressed.</p></div>
4381 <li><code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code></li>
4384 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4385 <div class="directive-section"><h2><a name="SetInputFilter" id="SetInputFilter">SetInputFilter</a> <a name="setinputfilter" id="setinputfilter">Directive</a></h2>
4386 <table class="directive">
4387 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process client requests and POST
4389 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetInputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4390 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4391 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4392 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4393 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4395 <p>The <code class="directive">SetInputFilter</code> directive sets the
4396 filter or filters which will process client requests and POST
4397 input when they are received by the server. This is in addition to
4398 any filters defined elsewhere, including the
4399 <code class="directive"><a href="../mod/mod_mime.html#addinputfilter">AddInputFilter</a></code>
4402 <p>If more than one filter is specified, they must be separated
4403 by semicolons in the order in which they should process the
4408 <li><a href="../filter.html">Filters</a> documentation</li>
4411 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4412 <div class="directive-section"><h2><a name="SetOutputFilter" id="SetOutputFilter">SetOutputFilter</a> <a name="setoutputfilter" id="setoutputfilter">Directive</a></h2>
4413 <table class="directive">
4414 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process responses from the
4416 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4417 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4418 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4419 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4420 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4422 <p>The <code class="directive">SetOutputFilter</code> directive sets the filters
4423 which will process responses from the server before they are
4424 sent to the client. This is in addition to any filters defined
4425 elsewhere, including the
4426 <code class="directive"><a href="../mod/mod_mime.html#addoutputfilter">AddOutputFilter</a></code>
4429 <p>For example, the following configuration will process all files
4430 in the <code>/www/data/</code> directory for server-side
4433 <pre class="prettyprint lang-config"><Directory "/www/data/">
4434 SetOutputFilter INCLUDES
4435 </Directory></pre>
4438 <p>If more than one filter is specified, they must be separated
4439 by semicolons in the order in which they should process the
4444 <li><a href="../filter.html">Filters</a> documentation</li>
4447 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4448 <div class="directive-section"><h2><a name="TimeOut" id="TimeOut">TimeOut</a> <a name="timeout" id="timeout">Directive</a></h2>
4449 <table class="directive">
4450 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for
4451 certain events before failing a request</td></tr>
4452 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TimeOut <var>seconds</var></code></td></tr>
4453 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TimeOut 60</code></td></tr>
4454 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4455 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4456 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4458 <p>The <code class="directive">TimeOut</code> directive defines the length
4459 of time Apache httpd will wait for I/O in various circumstances:</p>
4462 <li>When reading data from the client, the length of time to
4463 wait for a TCP packet to arrive if the read buffer is
4466 <li>When writing data to the client, the length of time to wait
4467 for an acknowledgement of a packet if the send buffer is
4470 <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>,
4471 the length of time to wait for output from a CGI script.</li>
4473 <li>In <code class="module"><a href="../mod/mod_ext_filter.html">mod_ext_filter</a></code>, the length of time to
4474 wait for output from a filtering process.</li>
4476 <li>In <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>, the default timeout value if
4477 <code class="directive"><a href="../mod/mod_proxy.html#proxytimeout">ProxyTimeout</a></code> is not
4483 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4484 <div class="directive-section"><h2><a name="TraceEnable" id="TraceEnable">TraceEnable</a> <a name="traceenable" id="traceenable">Directive</a></h2>
4485 <table class="directive">
4486 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines the behavior on <code>TRACE</code> requests</td></tr>
4487 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TraceEnable <var>[on|off|extended]</var></code></td></tr>
4488 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TraceEnable on</code></td></tr>
4489 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4490 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4491 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4493 <p>This directive overrides the behavior of <code>TRACE</code> for both
4494 the core server and <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>. The default
4495 <code>TraceEnable on</code> permits <code>TRACE</code> requests per
4496 RFC 2616, which disallows any request body to accompany the request.
4497 <code>TraceEnable off</code> causes the core server and
4498 <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> to return a <code>405</code> (Method not
4499 allowed) error to the client.</p>
4501 <p>Finally, for testing and diagnostic purposes only, request
4502 bodies may be allowed using the non-compliant <code>TraceEnable
4503 extended</code> directive. The core (as an origin server) will
4504 restrict the request body to 64k (plus 8k for chunk headers if
4505 <code>Transfer-Encoding: chunked</code> is used). The core will
4506 reflect the full headers and all chunk headers with the response
4507 body. As a proxy server, the request body is not restricted to 64k.</p>
4509 <div class="note"><h3>Note</h3>
4510 <p>Despite claims to the contrary, <code>TRACE</code> is not
4511 a security vulnerability, and there is no viable reason for
4512 it to be disabled. Doing so necessarily makes your server
4517 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4518 <div class="directive-section"><h2><a name="UnDefine" id="UnDefine">UnDefine</a> <a name="undefine" id="undefine">Directive</a></h2>
4519 <table class="directive">
4520 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Undefine the existence of a variable</td></tr>
4521 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UnDefine <var>parameter-name</var></code></td></tr>
4522 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4523 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4524 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4526 <p>Undoes the effect of a <code class="directive"><a href="#define">Define</a></code> or
4527 of passing a <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</p>
4528 <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
4529 <code>-D</code> arguments in any startup scripts.</p>
4530 <p>While this directive is supported in virtual host context,
4531 the changes it makes are visible to any later configuration
4532 directives, beyond any enclosing virtual host.</p>
4535 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4536 <div class="directive-section"><h2><a name="UseCanonicalName" id="UseCanonicalName">UseCanonicalName</a> <a name="usecanonicalname" id="usecanonicalname">Directive</a></h2>
4537 <table class="directive">
4538 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own name and
4540 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalName On|Off|DNS</code></td></tr>
4541 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalName Off</code></td></tr>
4542 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4543 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4544 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4546 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4547 URL -- that is, a URL that refers back to the same server. With
4548 <code>UseCanonicalName On</code> Apache httpd will use the hostname and port
4549 specified in the <code class="directive"><a href="#servername">ServerName</a></code>
4550 directive to construct the canonical name for the server. This name
4551 is used in all self-referential URLs, and for the values of
4552 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>
4554 <p>With <code>UseCanonicalName Off</code> Apache httpd will form
4555 self-referential URLs using the hostname and port supplied by
4556 the client if any are supplied (otherwise it will use the
4557 canonical name, as defined above). These values are the same
4558 that are used to implement <a href="../vhosts/name-based.html">name-based virtual hosts</a>
4559 and are available with the same clients. The CGI variables
4560 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
4561 constructed from the client supplied values as well.</p>
4563 <p>An example where this may be useful is on an intranet server
4564 where you have users connecting to the machine using short
4565 names such as <code>www</code>. You'll notice that if the users
4566 type a shortname and a URL which is a directory, such as
4567 <code>http://www/splat</code>, <em>without the trailing
4568 slash</em>, then Apache httpd will redirect them to
4569 <code>http://www.example.com/splat/</code>. If you have
4570 authentication enabled, this will cause the user to have to
4571 authenticate twice (once for <code>www</code> and once again
4572 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">
4573 the FAQ on this subject for more information</a>). But if
4574 <code class="directive">UseCanonicalName</code> is set <code>Off</code>, then
4575 Apache httpd will redirect to <code>http://www/splat/</code>.</p>
4577 <p>There is a third option, <code>UseCanonicalName DNS</code>,
4578 which is intended for use with mass IP-based virtual hosting to
4579 support ancient clients that do not provide a
4580 <code>Host:</code> header. With this option, Apache httpd does a
4581 reverse DNS lookup on the server IP address that the client
4582 connected to in order to work out self-referential URLs.</p>
4584 <div class="warning"><h3>Warning</h3>
4585 <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>,
4586 they may be broken by this option. The client is essentially free
4587 to give whatever value they want as a hostname. But if the CGI is
4588 only using <code>SERVER_NAME</code> to construct self-referential URLs,
4589 then it should be just fine.</p>
4594 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
4595 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4596 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4599 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4600 <div class="directive-section"><h2><a name="UseCanonicalPhysicalPort" id="UseCanonicalPhysicalPort">UseCanonicalPhysicalPort</a> <a name="usecanonicalphysicalport" id="usecanonicalphysicalport">Directive</a></h2>
4601 <table class="directive">
4602 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own port</td></tr>
4603 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalPhysicalPort On|Off</code></td></tr>
4604 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalPhysicalPort Off</code></td></tr>
4605 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4606 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4607 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4609 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4610 URL -- that is, a URL that refers back to the same server. With
4611 <code>UseCanonicalPhysicalPort On</code>, Apache httpd will, when
4612 constructing the canonical port for the server to honor
4613 the <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> directive,
4614 provide the actual physical port number being used by this request
4615 as a potential port. With <code>UseCanonicalPhysicalPort Off</code>,
4616 Apache httpd will not ever use the actual physical port number, instead
4617 relying on all configured information to construct a valid port number.</p>
4619 <div class="note"><h3>Note</h3>
4620 <p>The ordering of the lookup when the physical port is used is as
4623 <dt><code>UseCanonicalName On</code></dt>
4626 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4627 <li>Physical port</li>
4628 <li>Default port</li>
4631 <dt><code>UseCanonicalName Off | DNS</code></dt>
4634 <li>Parsed port from <code>Host:</code> header</li>
4635 <li>Physical port</li>
4636 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4637 <li>Default port</li>
4642 <p>With <code>UseCanonicalPhysicalPort Off</code>, the
4643 physical ports are removed from the ordering.</p>
4649 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
4650 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4651 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4654 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4655 <div class="directive-section"><h2><a name="VirtualHost" id="VirtualHost"><VirtualHost></a> <a name="virtualhost" id="virtualhost">Directive</a></h2>
4656 <table class="directive">
4657 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only to a specific
4658 hostname or IP address</td></tr>
4659 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><VirtualHost
4660 <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
4661 ...> ... </VirtualHost></code></td></tr>
4662 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4663 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4664 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4666 <p><code class="directive"><VirtualHost></code> and
4667 <code></VirtualHost></code> are used to enclose a group of
4668 directives that will apply only to a particular virtual host. Any
4669 directive that is allowed in a virtual host context may be
4670 used. When the server receives a request for a document on a
4671 particular virtual host, it uses the configuration directives
4672 enclosed in the <code class="directive"><VirtualHost></code>
4673 section. <var>Addr</var> can be any of the following, optionally followed by
4674 a colon and a port number (or *):</p>
4677 <li>The IP address of the virtual host;</li>
4679 <li>A fully qualified domain name for the IP address of the
4680 virtual host (not recommended);</li>
4682 <li>The character <code>*</code>, which acts as a wildcard and matches
4683 any IP address.</li>
4685 <li>The string <code>_default_</code>, which is an alias for <code>*</code></li>
4689 <pre class="prettyprint lang-config"><VirtualHost 10.1.2.3:80>
4690 ServerAdmin webmaster@host.example.com
4691 DocumentRoot "/www/docs/host.example.com"
4692 ServerName host.example.com
4693 ErrorLog "logs/host.example.com-error_log"
4694 TransferLog "logs/host.example.com-access_log"
4695 </VirtualHost></pre>
4699 <p>IPv6 addresses must be specified in square brackets because
4700 the optional port number could not be determined otherwise. An
4701 IPv6 example is shown below:</p>
4703 <pre class="prettyprint lang-config"><VirtualHost [2001:db8::a00:20ff:fea7:ccea]:80>
4704 ServerAdmin webmaster@host.example.com
4705 DocumentRoot "/www/docs/host.example.com"
4706 ServerName host.example.com
4707 ErrorLog "logs/host.example.com-error_log"
4708 TransferLog "logs/host.example.com-access_log"
4709 </VirtualHost></pre>
4712 <p>Each Virtual Host must correspond to a different IP address,
4713 different port number, or a different host name for the server,
4714 in the former case the server machine must be configured to
4715 accept IP packets for multiple addresses. (If the machine does
4716 not have multiple network interfaces, then this can be
4717 accomplished with the <code>ifconfig alias</code> command -- if
4718 your OS supports it).</p>
4720 <div class="note"><h3>Note</h3>
4721 <p>The use of <code class="directive"><VirtualHost></code> does
4722 <strong>not</strong> affect what addresses Apache httpd listens on. You
4723 may need to ensure that Apache httpd is listening on the correct addresses
4724 using <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>.</p>
4727 <p>A <code class="directive"><a href="#servername">ServerName</a></code> should be
4728 specified inside each <code class="directive"><VirtualHost></code> block. If it is absent, the
4729 <code class="directive"><a href="#servername">ServerName</a></code> from the "main"
4730 server configuration will be inherited.</p>
4732 <p>When a request is received, the server first maps it to the best matching
4733 <code class="directive"><VirtualHost></code> based on the local
4734 IP address and port combination only. Non-wildcards have a higher
4735 precedence. If no match based on IP and port occurs at all, the
4736 "main" server configuration is used.</p>
4738 <p>If multiple virtual hosts contain the best matching IP address and port,
4739 the server selects from these virtual hosts the best match based on the
4740 requested hostname. If no matching name-based virtual host is found,
4741 then the first listed virtual host that matched the IP address will be
4742 used. As a consequence, the first listed virtual host for a given IP address
4743 and port combination is the default virtual host for that IP and port
4746 <div class="warning"><h3>Security</h3>
4747 <p>See the <a href="../misc/security_tips.html">security tips</a>
4748 document for details on why your security could be compromised if the
4749 directory where log files are stored is writable by anyone other
4750 than the user that starts the server.</p>
4755 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4756 <li><a href="../dns-caveats.html">Issues Regarding DNS and
4757 Apache HTTP Server</a></li>
4758 <li><a href="../bind.html">Setting
4759 which addresses and ports Apache HTTP Server uses</a></li>
4760 <li><a href="../sections.html">How <Directory>, <Location>
4761 and <Files> sections work</a> for an explanation of how these
4762 different sections are combined when a request is received</li>
4765 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4766 <div class="directive-section"><h2><a name="Warning" id="Warning">Warning</a> <a name="warning" id="warning">Directive</a></h2>
4767 <table class="directive">
4768 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Warn from configuration parsing with a custom message</td></tr>
4769 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Warning <var>message</var></code></td></tr>
4770 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4771 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4772 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4773 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.5 and later</td></tr>
4775 <p>If an issue can be detected from within the configuration, this
4776 directive can be used to generate a custom warning message. The
4777 configuration parsing is not halted. The typical use is to check
4778 whether some user define options are set, and warn if not.</p>
4780 <pre class="prettyprint lang-config"># Example
4781 # tell when ReverseProxy is not set
4782 <IfDefine !ReverseProxy>
4783 Warning "reverse proxy is not started, hope this is okay!"
4786 <IfDefine ReverseProxy>
4787 # define custom proxy configuration
4788 </IfDefine></pre>
4794 <div class="bottomlang">
4795 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
4796 <a href="../en/mod/core.html" title="English"> en </a> |
4797 <a href="../es/mod/core.html" hreflang="es" rel="alternate" title="Español"> es </a> |
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4799 <a href="../ja/mod/core.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
4800 <a href="../tr/mod/core.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p>
4801 </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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