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18 <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>
19 <p class="apache">Apache HTTP Server Version 2.5</p>
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23 <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>
24 <div id="page-content">
25 <div id="preamble"><h1>Apache Core Features</h1>
27 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
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34 <table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Core Apache HTTP Server features that are always
36 <tr><th><a href="module-dict.html#Status">Status:</a></th><td>Core</td></tr></table>
38 <div id="quickview"><h3 class="directives">Directives</h3>
40 <li><img alt="" src="../images/down.gif" /> <a href="#acceptfilter">AcceptFilter</a></li>
41 <li><img alt="" src="../images/down.gif" /> <a href="#acceptpathinfo">AcceptPathInfo</a></li>
42 <li><img alt="" src="../images/down.gif" /> <a href="#accessfilename">AccessFileName</a></li>
43 <li><img alt="" src="../images/down.gif" /> <a href="#adddefaultcharset">AddDefaultCharset</a></li>
44 <li><img alt="" src="../images/down.gif" /> <a href="#allowencodedslashes">AllowEncodedSlashes</a></li>
45 <li><img alt="" src="../images/down.gif" /> <a href="#allowoverride">AllowOverride</a></li>
46 <li><img alt="" src="../images/down.gif" /> <a href="#allowoverridelist">AllowOverrideList</a></li>
47 <li><img alt="" src="../images/down.gif" /> <a href="#cgimapextension">CGIMapExtension</a></li>
48 <li><img alt="" src="../images/down.gif" /> <a href="#contentdigest">ContentDigest</a></li>
49 <li><img alt="" src="../images/down.gif" /> <a href="#defaultruntimedir">DefaultRuntimeDir</a></li>
50 <li><img alt="" src="../images/down.gif" /> <a href="#defaulttype">DefaultType</a></li>
51 <li><img alt="" src="../images/down.gif" /> <a href="#define">Define</a></li>
52 <li><img alt="" src="../images/down.gif" /> <a href="#directory"><Directory></a></li>
53 <li><img alt="" src="../images/down.gif" /> <a href="#directorymatch"><DirectoryMatch></a></li>
54 <li><img alt="" src="../images/down.gif" /> <a href="#documentroot">DocumentRoot</a></li>
55 <li><img alt="" src="../images/down.gif" /> <a href="#else"><Else></a></li>
56 <li><img alt="" src="../images/down.gif" /> <a href="#elseif"><ElseIf></a></li>
57 <li><img alt="" src="../images/down.gif" /> <a href="#enablemmap">EnableMMAP</a></li>
58 <li><img alt="" src="../images/down.gif" /> <a href="#enablesendfile">EnableSendfile</a></li>
59 <li><img alt="" src="../images/down.gif" /> <a href="#error">Error</a></li>
60 <li><img alt="" src="../images/down.gif" /> <a href="#errordocument">ErrorDocument</a></li>
61 <li><img alt="" src="../images/down.gif" /> <a href="#errorlog">ErrorLog</a></li>
62 <li><img alt="" src="../images/down.gif" /> <a href="#errorlogformat">ErrorLogFormat</a></li>
63 <li><img alt="" src="../images/down.gif" /> <a href="#extendedstatus">ExtendedStatus</a></li>
64 <li><img alt="" src="../images/down.gif" /> <a href="#fileetag">FileETag</a></li>
65 <li><img alt="" src="../images/down.gif" /> <a href="#files"><Files></a></li>
66 <li><img alt="" src="../images/down.gif" /> <a href="#filesmatch"><FilesMatch></a></li>
67 <li><img alt="" src="../images/down.gif" /> <a href="#forcetype">ForceType</a></li>
68 <li><img alt="" src="../images/down.gif" /> <a href="#gprofdir">GprofDir</a></li>
69 <li><img alt="" src="../images/down.gif" /> <a href="#hostnamelookups">HostnameLookups</a></li>
70 <li><img alt="" src="../images/down.gif" /> <a href="#if"><If></a></li>
71 <li><img alt="" src="../images/down.gif" /> <a href="#ifdefine"><IfDefine></a></li>
72 <li><img alt="" src="../images/down.gif" /> <a href="#ifmodule"><IfModule></a></li>
73 <li><img alt="" src="../images/down.gif" /> <a href="#include">Include</a></li>
74 <li><img alt="" src="../images/down.gif" /> <a href="#includeoptional">IncludeOptional</a></li>
75 <li><img alt="" src="../images/down.gif" /> <a href="#keepalive">KeepAlive</a></li>
76 <li><img alt="" src="../images/down.gif" /> <a href="#keepalivetimeout">KeepAliveTimeout</a></li>
77 <li><img alt="" src="../images/down.gif" /> <a href="#limit"><Limit></a></li>
78 <li><img alt="" src="../images/down.gif" /> <a href="#limitexcept"><LimitExcept></a></li>
79 <li><img alt="" src="../images/down.gif" /> <a href="#limitinternalrecursion">LimitInternalRecursion</a></li>
80 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestbody">LimitRequestBody</a></li>
81 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfields">LimitRequestFields</a></li>
82 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfieldsize">LimitRequestFieldSize</a></li>
83 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestline">LimitRequestLine</a></li>
84 <li><img alt="" src="../images/down.gif" /> <a href="#limitxmlrequestbody">LimitXMLRequestBody</a></li>
85 <li><img alt="" src="../images/down.gif" /> <a href="#location"><Location></a></li>
86 <li><img alt="" src="../images/down.gif" /> <a href="#locationmatch"><LocationMatch></a></li>
87 <li><img alt="" src="../images/down.gif" /> <a href="#loglevel">LogLevel</a></li>
88 <li><img alt="" src="../images/down.gif" /> <a href="#logleveloverride">LogLevelOverride</a></li>
89 <li><img alt="" src="../images/down.gif" /> <a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></li>
90 <li><img alt="" src="../images/down.gif" /> <a href="#maxrangeoverlaps">MaxRangeOverlaps</a></li>
91 <li><img alt="" src="../images/down.gif" /> <a href="#maxrangereversals">MaxRangeReversals</a></li>
92 <li><img alt="" src="../images/down.gif" /> <a href="#maxranges">MaxRanges</a></li>
93 <li><img alt="" src="../images/down.gif" /> <a href="#mutex">Mutex</a></li>
94 <li><img alt="" src="../images/down.gif" /> <a href="#namevirtualhost">NameVirtualHost</a></li>
95 <li><img alt="" src="../images/down.gif" /> <a href="#options">Options</a></li>
96 <li><img alt="" src="../images/down.gif" /> <a href="#protocol">Protocol</a></li>
97 <li><img alt="" src="../images/down.gif" /> <a href="#registerhttpmethod">RegisterHttpMethod</a></li>
98 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitcpu">RLimitCPU</a></li>
99 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitmem">RLimitMEM</a></li>
100 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitnproc">RLimitNPROC</a></li>
101 <li><img alt="" src="../images/down.gif" /> <a href="#scriptinterpretersource">ScriptInterpreterSource</a></li>
102 <li><img alt="" src="../images/down.gif" /> <a href="#seerequesttail">SeeRequestTail</a></li>
103 <li><img alt="" src="../images/down.gif" /> <a href="#serveradmin">ServerAdmin</a></li>
104 <li><img alt="" src="../images/down.gif" /> <a href="#serveralias">ServerAlias</a></li>
105 <li><img alt="" src="../images/down.gif" /> <a href="#servername">ServerName</a></li>
106 <li><img alt="" src="../images/down.gif" /> <a href="#serverpath">ServerPath</a></li>
107 <li><img alt="" src="../images/down.gif" /> <a href="#serverroot">ServerRoot</a></li>
108 <li><img alt="" src="../images/down.gif" /> <a href="#serversignature">ServerSignature</a></li>
109 <li><img alt="" src="../images/down.gif" /> <a href="#servertokens">ServerTokens</a></li>
110 <li><img alt="" src="../images/down.gif" /> <a href="#sethandler">SetHandler</a></li>
111 <li><img alt="" src="../images/down.gif" /> <a href="#setinputfilter">SetInputFilter</a></li>
112 <li><img alt="" src="../images/down.gif" /> <a href="#setoutputfilter">SetOutputFilter</a></li>
113 <li><img alt="" src="../images/down.gif" /> <a href="#timeout">TimeOut</a></li>
114 <li><img alt="" src="../images/down.gif" /> <a href="#traceenable">TraceEnable</a></li>
115 <li><img alt="" src="../images/down.gif" /> <a href="#undefine">UnDefine</a></li>
116 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalname">UseCanonicalName</a></li>
117 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></li>
118 <li><img alt="" src="../images/down.gif" /> <a href="#virtualhost"><VirtualHost></a></li>
119 <li><img alt="" src="../images/down.gif" /> <a href="#warning">Warning</a></li>
121 <ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div>
123 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
124 <div class="directive-section"><h2><a name="AcceptFilter" id="AcceptFilter">AcceptFilter</a> <a name="acceptfilter" id="acceptfilter">Directive</a></h2>
125 <table class="directive">
126 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures optimizations for a Protocol's Listener Sockets</td></tr>
127 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptFilter <var>protocol</var> <var>accept_filter</var></code></td></tr>
128 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
129 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
130 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
131 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>On Windows only available from Apache httpd 2.3.3 and later.
134 <p>This directive enables operating system specific optimizations for a
135 listening socket by the <code class="directive">Protocol</code> type.
136 The basic premise is for the kernel to not send a socket to the server
137 process until either data is received or an entire HTTP Request is buffered.
138 Only <a href="http://www.freebsd.org/cgi/man.cgi?query=accept_filter&sektion=9">
139 FreeBSD's Accept Filters</a>, Linux's more primitive
140 <code>TCP_DEFER_ACCEPT</code>, and Windows' optimized AcceptEx()
141 are currently supported.</p>
143 <p>Using <code>none</code> for an argument will disable any accept filters
144 for that protocol. This is useful for protocols that require a server
145 send data first, such as <code>ftp:</code> or <code>nntp</code>:</p>
146 <pre class="prettyprint lang-config"> AcceptFilter nntp none</pre>
149 <p>The default protocol names are <code>https</code> for port 443
150 and <code>http</code> for all other ports. To specify another protocol
151 is being used with a listening port, add the <var>protocol</var>
152 argument to the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>
155 <p>The default values on FreeBSD are:</p>
156 <pre class="prettyprint lang-config">AcceptFilter http httpready
157 AcceptFilter https dataready</pre>
160 <p>The <code>httpready</code> accept filter buffers entire HTTP requests at
161 the kernel level. Once an entire request is received, the kernel then
162 sends it to the server. See the
163 <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_http&sektion=9">
164 accf_http(9)</a> man page for more details. Since HTTPS requests are
165 encrypted only the <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_data&sektion=9">
166 accf_data(9)</a> filter is used.</p>
168 <p>The default values on Linux are:</p>
169 <pre class="prettyprint lang-config">AcceptFilter http data
170 AcceptFilter https data</pre>
173 <p>Linux's <code>TCP_DEFER_ACCEPT</code> does not support buffering http
174 requests. Any value besides <code>none</code> will enable
175 <code>TCP_DEFER_ACCEPT</code> on that listener. For more details
177 <a href="http://homepages.cwi.nl/~aeb/linux/man2html/man7/tcp.7.html">
178 tcp(7)</a> man page.</p>
180 <p>The default values on Windows are:</p>
181 <pre class="prettyprint lang-config">AcceptFilter http data
182 AcceptFilter https data</pre>
185 <p>Window's mpm_winnt interprets the AcceptFilter to toggle the AcceptEx()
186 API, and does not support http protocol buffering. There are two values
187 which utilize the Windows AcceptEx() API and will recycle network
188 sockets between connections. <code>data</code> waits until data has
189 been transmitted as documented above, and the initial data buffer and
190 network endpoint addresses are all retrieved from the single AcceptEx()
191 invocation. <code>connect</code> will use the AcceptEx() API, also
192 retrieve the network endpoint addresses, but like <code>none</code>
193 the <code>connect</code> option does not wait for the initial data
196 <p>On Windows, <code>none</code> uses accept() rather than AcceptEx()
197 and will not recycle sockets between connections. This is useful for
198 network adapters with broken driver support, as well as some virtual
199 network providers such as vpn drivers, or spam, virus or spyware
205 <li><code class="directive"><a href="#protocol">Protocol</a></code></li>
208 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
209 <div class="directive-section"><h2><a name="AcceptPathInfo" id="AcceptPathInfo">AcceptPathInfo</a> <a name="acceptpathinfo" id="acceptpathinfo">Directive</a></h2>
210 <table class="directive">
211 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Resources accept trailing pathname information</td></tr>
212 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptPathInfo On|Off|Default</code></td></tr>
213 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AcceptPathInfo Default</code></td></tr>
214 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
215 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
216 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
217 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
220 <p>This directive controls whether requests that contain trailing
221 pathname information that follows an actual filename (or
222 non-existent file in an existing directory) will be accepted or
223 rejected. The trailing pathname information can be made
224 available to scripts in the <code>PATH_INFO</code> environment
227 <p>For example, assume the location <code>/test/</code> points to
228 a directory that contains only the single file
229 <code>here.html</code>. Then requests for
230 <code>/test/here.html/more</code> and
231 <code>/test/nothere.html/more</code> both collect
232 <code>/more</code> as <code>PATH_INFO</code>.</p>
234 <p>The three possible arguments for the
235 <code class="directive">AcceptPathInfo</code> directive are:</p>
237 <dt><code>Off</code></dt><dd>A request will only be accepted if it
238 maps to a literal path that exists. Therefore a request with
239 trailing pathname information after the true filename such as
240 <code>/test/here.html/more</code> in the above example will return
241 a 404 NOT FOUND error.</dd>
243 <dt><code>On</code></dt><dd>A request will be accepted if a
244 leading path component maps to a file that exists. The above
245 example <code>/test/here.html/more</code> will be accepted if
246 <code>/test/here.html</code> maps to a valid file.</dd>
248 <dt><code>Default</code></dt><dd>The treatment of requests with
249 trailing pathname information is determined by the <a href="../handler.html">handler</a> responsible for the request.
250 The core handler for normal files defaults to rejecting
251 <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
252 <code>PATH_INFO</code> by default.</dd>
255 <p>The primary purpose of the <code>AcceptPathInfo</code>
256 directive is to allow you to override the handler's choice of
257 accepting or rejecting <code>PATH_INFO</code>. This override is required,
258 for example, when you use a <a href="../filter.html">filter</a>, such
259 as <a href="mod_include.html">INCLUDES</a>, to generate content
260 based on <code>PATH_INFO</code>. The core handler would usually reject
261 the request, so you can use the following configuration to enable
264 <pre class="prettyprint lang-config"><Files "mypaths.shtml">
266 SetOutputFilter INCLUDES
273 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
274 <div class="directive-section"><h2><a name="AccessFileName" id="AccessFileName">AccessFileName</a> <a name="accessfilename" id="accessfilename">Directive</a></h2>
275 <table class="directive">
276 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Name of the distributed configuration file</td></tr>
277 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AccessFileName <var>filename</var> [<var>filename</var>] ...</code></td></tr>
278 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AccessFileName .htaccess</code></td></tr>
279 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
280 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
281 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
283 <p>While processing a request the server looks for
284 the first existing configuration file from this list of names in
285 every directory of the path to the document, if distributed
286 configuration files are <a href="#allowoverride">enabled for that
287 directory</a>. For example:</p>
289 <pre class="prettyprint lang-config">AccessFileName .acl</pre>
292 <p>before returning the document
293 <code>/usr/local/web/index.html</code>, the server will read
294 <code>/.acl</code>, <code>/usr/.acl</code>,
295 <code>/usr/local/.acl</code> and <code>/usr/local/web/.acl</code>
296 for directives, unless they have been disabled with</p>
298 <pre class="prettyprint lang-config"><Directory />
300 </Directory></pre>
305 <li><code class="directive"><a href="#allowoverride">AllowOverride</a></code></li>
306 <li><a href="../configuring.html">Configuration Files</a></li>
307 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
310 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
311 <div class="directive-section"><h2><a name="AddDefaultCharset" id="AddDefaultCharset">AddDefaultCharset</a> <a name="adddefaultcharset" id="adddefaultcharset">Directive</a></h2>
312 <table class="directive">
313 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Default charset parameter to be added when a response
314 content-type is <code>text/plain</code> or <code>text/html</code></td></tr>
315 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AddDefaultCharset On|Off|<var>charset</var></code></td></tr>
316 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AddDefaultCharset Off</code></td></tr>
317 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
318 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
319 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
320 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
322 <p>This directive specifies a default value for the media type
323 charset parameter (the name of a character encoding) to be added
324 to a response if and only if the response's content-type is either
325 <code>text/plain</code> or <code>text/html</code>. This should override
326 any charset specified in the body of the response via a <code>META</code>
327 element, though the exact behavior is often dependent on the user's client
328 configuration. A setting of <code>AddDefaultCharset Off</code>
329 disables this functionality. <code>AddDefaultCharset On</code> enables
330 a default charset of <code>iso-8859-1</code>. Any other value is assumed
331 to be the <var>charset</var> to be used, which should be one of the
332 <a href="http://www.iana.org/assignments/character-sets">IANA registered
333 charset values</a> for use in Internet media types (MIME types).
336 <pre class="prettyprint lang-config">AddDefaultCharset utf-8</pre>
339 <p><code class="directive">AddDefaultCharset</code> should only be used when all
340 of the text resources to which it applies are known to be in that
341 character encoding and it is too inconvenient to label their charset
342 individually. One such example is to add the charset parameter
343 to resources containing generated content, such as legacy CGI
344 scripts, that might be vulnerable to cross-site scripting attacks
345 due to user-provided data being included in the output. Note, however,
346 that a better solution is to just fix (or delete) those scripts, since
347 setting a default charset does not protect users that have enabled
348 the "auto-detect character encoding" feature on their browser.</p>
352 <li><code class="directive"><a href="../mod/mod_mime.html#addcharset">AddCharset</a></code></li>
355 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
356 <div class="directive-section"><h2><a name="AllowEncodedSlashes" id="AllowEncodedSlashes">AllowEncodedSlashes</a> <a name="allowencodedslashes" id="allowencodedslashes">Directive</a></h2>
357 <table class="directive">
358 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines whether encoded path separators in URLs are allowed to
359 be passed through</td></tr>
360 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowEncodedSlashes On|Off|NoDecode</code></td></tr>
361 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowEncodedSlashes Off</code></td></tr>
362 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
363 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
364 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
365 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>
366 NoDecode option available in 2.3.12 and later.</td></tr>
368 <p>The <code class="directive">AllowEncodedSlashes</code> directive allows URLs
369 which contain encoded path separators (<code>%2F</code> for <code>/</code>
370 and additionally <code>%5C</code> for <code>\</code> on according systems)
371 to be used in the path info.</p>
373 <p>With the default value, <code>Off</code>, such URLs are refused
374 with a 404 (Not found) error.</p>
376 <p>With the value <code>On</code>, such URLs are accepted, and encoded
377 slashes are decoded like all other encoded characters.</p>
379 <p>With the value <code>NoDecode</code>, such URLs are accepted, but
380 encoded slashes are not decoded but left in their encoded state.</p>
382 <p>Turning <code class="directive">AllowEncodedSlashes</code> <code>On</code> is
383 mostly useful when used in conjunction with <code>PATH_INFO</code>.</p>
385 <div class="note"><h3>Note</h3>
386 <p>If encoded slashes are needed in path info, use of <code>NoDecode</code> is
387 strongly recommended as a security measure. Allowing slashes
388 to be decoded could potentially allow unsafe paths.</p>
393 <li><code class="directive"><a href="#acceptpathinfo">AcceptPathInfo</a></code></li>
396 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
397 <div class="directive-section"><h2><a name="AllowOverride" id="AllowOverride">AllowOverride</a> <a name="allowoverride" id="allowoverride">Directive</a></h2>
398 <table class="directive">
399 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Types of directives that are allowed in
400 <code>.htaccess</code> files</td></tr>
401 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowOverride All|None|<var>directive-type</var>
402 [<var>directive-type</var>] ...</code></td></tr>
403 <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>
404 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
405 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
406 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
408 <p>When the server finds an <code>.htaccess</code> file (as
409 specified by <code class="directive"><a href="#accessfilename">AccessFileName</a></code>)
410 it needs to know which directives declared in that file can override
411 earlier configuration directives.</p>
413 <div class="note"><h3>Only available in <Directory> sections</h3>
414 <code class="directive">AllowOverride</code> is valid only in
415 <code class="directive"><a href="#directory"><Directory></a></code>
416 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
417 <code class="directive"><a href="#files"><Files></a></code> sections.
420 <p>When this directive is set to <code>None</code> and <code class="directive"><a href="#allowoverridelist">AllowOverrideList</a></code> is set to
421 <code>None</code> <a href="#accessfilename">.htaccess</a> files are
422 completely ignored. In this case, the server will not even attempt
423 to read <code>.htaccess</code> files in the filesystem.</p>
425 <p>When this directive is set to <code>All</code>, then any
426 directive which has the .htaccess <a href="directive-dict.html#Context">Context</a> is allowed in
427 <code>.htaccess</code> files.</p>
429 <p>The <var>directive-type</var> can be one of the following
430 groupings of directives.</p>
437 Allow use of the authorization directives (<code class="directive"><a href="../mod/mod_authz_dbm.html#authdbmgroupfile">AuthDBMGroupFile</a></code>,
438 <code class="directive"><a href="../mod/mod_authn_dbm.html#authdbmuserfile">AuthDBMUserFile</a></code>,
439 <code class="directive"><a href="../mod/mod_authz_groupfile.html#authgroupfile">AuthGroupFile</a></code>,
440 <code class="directive"><a href="../mod/mod_authn_core.html#authname">AuthName</a></code>,
441 <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>
446 Allow use of the directives controlling document types
447 (<code class="directive"><a href="#errordocument">ErrorDocument</a></code>,
448 <code class="directive"><a href="#forcetype">ForceType</a></code>,
449 <code class="directive"><a href="../mod/mod_negotiation.html#languagepriority">LanguagePriority</a></code>,
450 <code class="directive"><a href="#sethandler">SetHandler</a></code>,
451 <code class="directive"><a href="#setinputfilter">SetInputFilter</a></code>,
452 <code class="directive"><a href="#setoutputfilter">SetOutputFilter</a></code>, and
453 <code class="module"><a href="../mod/mod_mime.html">mod_mime</a></code> Add* and Remove* directives),
454 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>),
455 <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>),
456 <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
457 <code class="directive"><a href="../mod/mod_actions.html#action">Action</a></code> from
458 <code class="module"><a href="../mod/mod_actions.html">mod_actions</a></code>.
464 Allow use of the directives controlling directory indexing
465 (<code class="directive"><a href="../mod/mod_autoindex.html#adddescription">AddDescription</a></code>,
466 <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>,
467 <code class="directive"><a href="../mod/mod_autoindex.html#addiconbytype">AddIconByType</a></code>,
468 <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>,
474 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>
479 <dt>Nonfatal=[Override|Unknown|All]</dt>
482 Allow use of AllowOverride option to treat syntax errors in
483 .htaccess as non-fatal: instead of causing an Internal Server
484 Error, disallowed or unrecognised directives will be ignored
485 and a warning logged:
487 <li><strong>Nonfatal=Override</strong> treats directives
488 forbidden by AllowOverride as non-fatal.</li>
489 <li><strong>Nonfatal=Unknown</strong> treats unknown directives
490 as non-fatal. This covers typos and directives implemented
491 by a module that's not present.</li>
492 <li><strong>Nonfatal=All</strong> treats both the above as non-fatal.</li>
494 <p>Note that a syntax error in a valid directive will still cause
495 an internal server error.</p>
496 <div class="warning"><h3>Security</h3>
497 Nonfatal errors may have security implications for .htaccess users.
498 For example, if AllowOverride disallows AuthConfig, users'
499 configuration designed to restrict access to a site will be disabled.
503 <dt>Options[=<var>Option</var>,...]</dt>
506 Allow use of the directives controlling specific directory
507 features (<code class="directive"><a href="#options">Options</a></code> and
508 <code class="directive"><a href="../mod/mod_include.html#xbithack">XBitHack</a></code>).
509 An equal sign may be given followed by a comma (but no spaces)
510 separated lists of options that may be set using the <code class="directive"><a href="#options">Options</a></code> command.
512 <div class="note"><h3>Implicit disabling of Options</h3>
513 <p>Even though the list of options that may be used in .htaccess files
514 can be limited with this directive, as long as any <code class="directive"><a href="#options">Options</a></code> directive is allowed any
515 other inherited option can be disabled by using the non-relative
516 syntax. In other words, this mechanism cannot force a specific option
517 to remain <em>set</em> while allowing any others to be set.
520 <div class="example"><p><code>
521 AllowOverride Options=Indexes,MultiViews
528 <pre class="prettyprint lang-config">AllowOverride AuthConfig Indexes</pre>
531 <p>In the example above all directives that are neither in the group
532 <code>AuthConfig</code> nor <code>Indexes</code> cause an internal
535 <div class="note"><p>For security and performance reasons, do not set
536 <code>AllowOverride</code> to anything other than <code>None</code>
537 in your <code><Directory /></code> block. Instead, find (or
538 create) the <code><Directory></code> block that refers to the
539 directory where you're actually planning to place a
540 <code>.htaccess</code> file.</p>
545 <li><code class="directive"><a href="#accessfilename">AccessFileName</a></code></li>
546 <li><code class="directive"><a href="#allowoverridelist">AllowOverrideList</a></code></li>
547 <li><a href="../configuring.html">Configuration Files</a></li>
548 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
551 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
552 <div class="directive-section"><h2><a name="AllowOverrideList" id="AllowOverrideList">AllowOverrideList</a> <a name="allowoverridelist" id="allowoverridelist">Directive</a></h2>
553 <table class="directive">
554 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Individual directives that are allowed in
555 <code>.htaccess</code> files</td></tr>
556 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowOverrideList None|<var>directive</var>
557 [<var>directive-type</var>] ...</code></td></tr>
558 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowOverrideList None</code></td></tr>
559 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
560 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
561 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
563 <p>When the server finds an <code>.htaccess</code> file (as
564 specified by <code class="directive"><a href="#accessfilename">AccessFileName</a></code>)
565 it needs to know which directives declared in that file can override
566 earlier configuration directives.</p>
568 <div class="note"><h3>Only available in <Directory> sections</h3>
569 <code class="directive">AllowOverrideList</code> is valid only in
570 <code class="directive"><a href="#directory"><Directory></a></code>
571 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
572 <code class="directive"><a href="#files"><Files></a></code> sections.
575 <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>,
576 then <a href="#accessfilename">.htaccess</a> files are completely
577 ignored. In this case, the server will not even attempt to read
578 <code>.htaccess</code> files in the filesystem.</p>
582 <pre class="prettyprint lang-config">AllowOverride None
583 AllowOverrideList Redirect RedirectMatch</pre>
586 <p>In the example above only the <code>Redirect</code> and
587 <code>RedirectMatch</code> directives are allowed. All others will
588 cause an internal server error.</p>
592 <pre class="prettyprint lang-config">AllowOverride AuthConfig
593 AllowOverrideList CookieTracking CookieName</pre>
596 <p>In the example above <code class="directive"><a href="#allowoverride">AllowOverride
597 </a></code> grants permission to the <code>AuthConfig</code>
598 directive grouping and <code class="directive">AllowOverrideList</code> grants
599 permission to only two directives from the <code>FileInfo</code> directive
600 grouping. All others will cause an internal server error.</p>
604 <li><code class="directive"><a href="#accessfilename">AccessFileName</a></code></li>
605 <li><code class="directive"><a href="#allowoverride">AllowOverride</a></code></li>
606 <li><a href="../configuring.html">Configuration Files</a></li>
607 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
610 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
611 <div class="directive-section"><h2><a name="CGIMapExtension" id="CGIMapExtension">CGIMapExtension</a> <a name="cgimapextension" id="cgimapextension">Directive</a></h2>
612 <table class="directive">
613 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
615 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CGIMapExtension <var>cgi-path</var> <var>.extension</var></code></td></tr>
616 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
617 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
618 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
619 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
620 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>NetWare only</td></tr>
622 <p>This directive is used to control how Apache httpd finds the
623 interpreter used to run CGI scripts. For example, setting
624 <code>CGIMapExtension sys:\foo.nlm .foo</code> will
625 cause all CGI script files with a <code>.foo</code> extension to
626 be passed to the FOO interpreter.</p>
629 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
630 <div class="directive-section"><h2><a name="ContentDigest" id="ContentDigest">ContentDigest</a> <a name="contentdigest" id="contentdigest">Directive</a></h2>
631 <table class="directive">
632 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables the generation of <code>Content-MD5</code> HTTP Response
634 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ContentDigest On|Off</code></td></tr>
635 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ContentDigest Off</code></td></tr>
636 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
637 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
638 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
639 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
641 <p>This directive enables the generation of
642 <code>Content-MD5</code> headers as defined in RFC1864
643 respectively RFC2616.</p>
645 <p>MD5 is an algorithm for computing a "message digest"
646 (sometimes called "fingerprint") of arbitrary-length data, with
647 a high degree of confidence that any alterations in the data
648 will be reflected in alterations in the message digest.</p>
650 <p>The <code>Content-MD5</code> header provides an end-to-end
651 message integrity check (MIC) of the entity-body. A proxy or
652 client may check this header for detecting accidental
653 modification of the entity-body in transit. Example header:</p>
655 <div class="example"><p><code>
656 Content-MD5: AuLb7Dp1rqtRtxz2m9kRpA==
659 <p>Note that this can cause performance problems on your server
660 since the message digest is computed on every request (the
661 values are not cached).</p>
663 <p><code>Content-MD5</code> is only sent for documents served
664 by the <code class="module"><a href="../mod/core.html">core</a></code>, and not by any module. For example,
665 SSI documents, output from CGI scripts, and byte range responses
666 do not have this header.</p>
669 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
670 <div class="directive-section"><h2><a name="DefaultRuntimeDir" id="DefaultRuntimeDir">DefaultRuntimeDir</a> <a name="defaultruntimedir" id="defaultruntimedir">Directive</a></h2>
671 <table class="directive">
672 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server run-time files</td></tr>
673 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultRuntimeDir <var>directory-path</var></code></td></tr>
674 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultRuntimeDir DEFAULT_REL_RUNTIMEDIR (logs/)</code></td></tr>
675 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
676 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
677 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
679 <p>The <code class="directive">DefaultRuntimeDir</code> directive sets the
680 directory in which the server will create various run-time files
681 (shared memory, locks, etc.). If set as a relative path, the full path
682 will be relative to <code class="directive">ServerRoot</code>.</p>
684 <p><strong>Example</strong></p>
685 <pre class="prettyprint lang-config">DefaultRuntimeDir scratch/</pre>
688 <p>The default location of <code class="directive">DefaultRuntimeDir</code> may be
689 modified by changing the <code>DEFAULT_REL_RUNTIMEDIR</code> #define
692 <p>Note: <code class="directive">ServerRoot</code> should be specified before this
693 directive is used, otherwise the default value of <code class="directive">ServerRoot</code>
694 would be used to set the base directory.</p>
699 <li><a href="../misc/security_tips.html#serverroot">the
700 security tips</a> for information on how to properly set
701 permissions on the <code class="directive">ServerRoot</code></li>
704 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
705 <div class="directive-section"><h2><a name="DefaultType" id="DefaultType">DefaultType</a> <a name="defaulttype" id="defaulttype">Directive</a></h2>
706 <table class="directive">
707 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>This directive has no effect other than to emit warnings
708 if the value is not <code>none</code>. In prior versions, DefaultType
709 would specify a default media type to assign to response content for
710 which no other media type configuration could be found.
712 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultType <var>media-type|none</var></code></td></tr>
713 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultType none</code></td></tr>
714 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
715 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
716 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
717 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
718 <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.
721 <p>This directive has been disabled. For backwards compatibility
722 of configuration files, it may be specified with the value
723 <code>none</code>, meaning no default media type. For example:</p>
725 <pre class="prettyprint lang-config">DefaultType None</pre>
728 <p><code>DefaultType None</code> is only available in
729 httpd-2.2.7 and later.</p>
731 <p>Use the mime.types configuration file and the
732 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code> to configure media
733 type assignments via file extensions, or the
734 <code class="directive"><a href="#forcetype">ForceType</a></code> directive to configure
735 the media type for specific resources. Otherwise, the server will
736 send the response without a Content-Type header field and the
737 recipient may attempt to guess the media type.</p>
740 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
741 <div class="directive-section"><h2><a name="Define" id="Define">Define</a> <a name="define" id="define">Directive</a></h2>
742 <table class="directive">
743 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Define a variable</td></tr>
744 <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>
745 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
746 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
747 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
749 <p>In its one parameter form, <code class="directive">Define</code> is equivalent
750 to passing the <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>. It
751 can be used to toggle the use of
752 <code class="directive"><a href="#ifdefine"><IfDefine></a></code> sections
753 without needing to alter <code>-D</code> arguments in any startup
756 <p>In addition to that, if the second parameter is given, a config variable
757 is set to this value. The variable can be used in the configuration using
758 the <code>${VAR}</code> syntax. The variable is always globally defined
759 and not limited to the scope of the surrounding config section.</p>
761 <pre class="prettyprint lang-config"><IfDefine TEST>
762 Define servername test.example.com
764 <IfDefine !TEST>
765 Define servername www.example.com
769 DocumentRoot /var/www/${servername}/htdocs</pre>
772 <p>Variable names may not contain colon ":" characters, to avoid clashes
773 with <code class="directive"><a href="../mod/mod_rewrite.html#rewritemap">RewriteMap</a></code>'s syntax.</p>
776 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
777 <div class="directive-section"><h2><a name="Directory" id="Directory"><Directory></a> <a name="directory" id="directory">Directive</a></h2>
778 <table class="directive">
779 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose a group of directives that apply only to the
780 named file-system directory, sub-directories, and their contents.</td></tr>
781 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Directory <var>directory-path</var>>
782 ... </Directory></code></td></tr>
783 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
784 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
785 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
787 <p><code class="directive"><Directory></code> and
788 <code></Directory></code> are used to enclose a group of
789 directives that will apply only to the named directory,
790 sub-directories of that directory, and the files within the respective
791 directories. Any directive that is allowed
792 in a directory context may be used. <var>Directory-path</var> is
793 either the full path to a directory, or a wild-card string using
794 Unix shell-style matching. In a wild-card string, <code>?</code> matches
795 any single character, and <code>*</code> matches any sequences of
796 characters. You may also use <code>[]</code> character ranges. None
797 of the wildcards match a `/' character, so <code><Directory
798 /*/public_html></code> will not match
799 <code>/home/user/public_html</code>, but <code><Directory
800 /home/*/public_html></code> will match. Example:</p>
802 <pre class="prettyprint lang-config"><Directory "/usr/local/httpd/htdocs">
803 Options Indexes FollowSymLinks
804 </Directory></pre>
808 <p>Be careful with the <var>directory-path</var> arguments:
809 They have to literally match the filesystem path which Apache httpd uses
810 to access the files. Directives applied to a particular
811 <code><Directory></code> will not apply to files accessed from
812 that same directory via a different path, such as via different symbolic
816 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular
817 expressions</a> can also be used, with the addition of the
818 <code>~</code> character. For example:</p>
820 <pre class="prettyprint lang-config"><Directory ~ "^/www/[0-9]{3}">
822 </Directory></pre>
825 <p>would match directories in <code>/www/</code> that consisted of
828 <p>If multiple (non-regular expression) <code class="directive"><Directory></code> sections
829 match the directory (or one of its parents) containing a document,
830 then the directives are applied in the order of shortest match
831 first, interspersed with the directives from the <a href="#accessfilename">.htaccess</a> files. For example,
834 <pre class="prettyprint lang-config"><Directory />
838 <Directory "/home">
839 AllowOverride FileInfo
840 </Directory></pre>
843 <p>for access to the document <code>/home/web/dir/doc.html</code>
847 <li>Apply directive <code>AllowOverride None</code>
848 (disabling <code>.htaccess</code> files).</li>
850 <li>Apply directive <code>AllowOverride FileInfo</code> (for
851 directory <code>/home</code>).</li>
853 <li>Apply any <code>FileInfo</code> directives in
854 <code>/home/.htaccess</code>, <code>/home/web/.htaccess</code> and
855 <code>/home/web/dir/.htaccess</code> in that order.</li>
858 <p>Regular expressions are not considered until after all of the
859 normal sections have been applied. Then all of the regular
860 expressions are tested in the order they appeared in the
861 configuration file. For example, with</p>
863 <pre class="prettyprint lang-config"><Directory ~ "abc$">
864 # ... directives here ...
865 </Directory></pre>
868 <p>the regular expression section won't be considered until after
869 all normal <code class="directive"><Directory></code>s and
870 <code>.htaccess</code> files have been applied. Then the regular
871 expression will match on <code>/home/abc/public_html/abc</code> and
872 the corresponding <code class="directive"><Directory></code> will
875 <p><strong>Note that the default access for
876 <code><Directory /></code> is to permit all access.
877 This means that Apache httpd will serve any file mapped from an URL. It is
878 recommended that you change this with a block such
881 <pre class="prettyprint lang-config"><Directory />
883 </Directory></pre>
886 <p><strong>and then override this for directories you
887 <em>want</em> accessible. See the <a href="../misc/security_tips.html">Security Tips</a> page for more
888 details.</strong></p>
890 <p>The directory sections occur in the <code>httpd.conf</code> file.
891 <code class="directive"><Directory></code> directives
892 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>
896 <li><a href="../sections.html">How <Directory>,
897 <Location> and <Files> sections work</a> for an
898 explanation of how these different sections are combined when a
899 request is received</li>
902 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
903 <div class="directive-section"><h2><a name="DirectoryMatch" id="DirectoryMatch"><DirectoryMatch></a> <a name="directorymatch" id="directorymatch">Directive</a></h2>
904 <table class="directive">
905 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose directives that apply to
906 the contents of file-system directories matching a regular expression.</td></tr>
907 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><DirectoryMatch <var>regex</var>>
908 ... </DirectoryMatch></code></td></tr>
909 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
910 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
911 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
913 <p><code class="directive"><DirectoryMatch></code> and
914 <code></DirectoryMatch></code> are used to enclose a group
915 of directives which will apply only to the named directory (and the files within),
916 the same as <code class="directive"><a href="#directory"><Directory></a></code>.
917 However, it takes as an argument a
918 <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>. For example:</p>
920 <pre class="prettyprint lang-config"><DirectoryMatch "^/www/(.+/)?[0-9]{3}">
922 </DirectoryMatch></pre>
925 <p>would match directories in <code>/www/</code> that consisted of three
928 <div class="note"><h3>Compatability</h3>
929 Prior to 2.3.9, this directive implicitly applied to sub-directories
930 (like <code class="directive"><a href="#directory"><Directory></a></code>) and
931 could not match the end of line symbol ($). In 2.3.9 and later,
932 only directories that match the expression are affected by the enclosed
936 <div class="note"><h3>Trailing Slash</h3>
937 This directive applies to requests for directories that may or may
938 not end in a trailing slash, so expressions that are anchored to the
939 end of line ($) must be written with care.
942 <p>From 2.4.8 onwards, named groups and backreferences are captured and
943 written to the environment with the corresponding name prefixed with
944 "MATCH_" and in upper case. This allows elements of paths to be referenced
945 from within <a href="../expr.html">expressions</a> and modules like
946 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
947 (unnamed) backreferences are ignored. Use named groups instead.</p>
949 <pre class="prettyprint lang-config"><DirectoryMatch ^/var/www/combined/(?<sitename>[^/]+)>
950 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
951 </DirectoryMatch></pre>
956 <li><code class="directive"><a href="#directory"><Directory></a></code> for
957 a description of how regular expressions are mixed in with normal
958 <code class="directive"><Directory></code>s</li>
959 <li><a href="../sections.html">How <Directory>, <Location> and
960 <Files> sections work</a> for an explanation of how these different
961 sections are combined when a request is received</li>
964 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
965 <div class="directive-section"><h2><a name="DocumentRoot" id="DocumentRoot">DocumentRoot</a> <a name="documentroot" id="documentroot">Directive</a></h2>
966 <table class="directive">
967 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory that forms the main document tree visible
968 from the web</td></tr>
969 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DocumentRoot <var>directory-path</var></code></td></tr>
970 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DocumentRoot /usr/local/apache/htdocs</code></td></tr>
971 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
972 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
973 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
975 <p>This directive sets the directory from which <code class="program"><a href="../programs/httpd.html">httpd</a></code>
976 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
977 path from the requested URL to the document root to make the
978 path to the document. Example:</p>
980 <pre class="prettyprint lang-config">DocumentRoot "/usr/web"</pre>
984 <code>http://my.example.com/index.html</code> refers to
985 <code>/usr/web/index.html</code>. If the <var>directory-path</var> is
986 not absolute then it is assumed to be relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
988 <p>The <code class="directive">DocumentRoot</code> should be specified without
989 a trailing slash.</p>
993 <li><a href="../urlmapping.html#documentroot">Mapping URLs to Filesystem
997 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
998 <div class="directive-section"><h2><a name="Else" id="Else"><Else></a> <a name="else" id="else">Directive</a></h2>
999 <table class="directive">
1000 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if the condition of a
1001 previous <code class="directive"><a href="#if"><If></a></code> or
1002 <code class="directive"><a href="#elseif"><ElseIf></a></code> section is not
1003 satisfied by a request at runtime</td></tr>
1004 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Else> ... </Else></code></td></tr>
1005 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1006 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1007 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1008 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1010 <p>The <code class="directive"><Else></code> applies the enclosed
1011 directives if and only if the most recent
1012 <code class="directive"><If></code> or
1013 <code class="directive"><ElseIf></code> section
1014 in the same scope has not been applied.
1015 For example: In </p>
1017 <pre class="prettyprint lang-config"><If "-z req('Host')">
1025 <p> The <code class="directive"><If></code> would match HTTP/1.0
1026 requests without a <var>Host:</var> header and the
1027 <code class="directive"><Else></code> would match requests
1028 with a <var>Host:</var> header.</p>
1033 <li><code class="directive"><a href="#if"><If></a></code></li>
1034 <li><code class="directive"><a href="#elseif"><ElseIf></a></code></li>
1035 <li><a href="../sections.html">How <Directory>, <Location>,
1036 <Files> sections work</a> for an explanation of how these
1037 different sections are combined when a request is received.
1038 <code class="directive"><If></code>,
1039 <code class="directive"><ElseIf></code>, and
1040 <code class="directive"><Else></code> are applied last.</li>
1043 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1044 <div class="directive-section"><h2><a name="ElseIf" id="ElseIf"><ElseIf></a> <a name="elseif" id="elseif">Directive</a></h2>
1045 <table class="directive">
1046 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is satisfied
1047 by a request at runtime while the condition of a previous
1048 <code class="directive"><a href="#if"><If></a></code> or
1049 <code class="directive"><ElseIf></code> section is not
1051 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><ElseIf <var>expression</var>> ... </ElseIf></code></td></tr>
1052 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1053 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1054 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1055 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1057 <p>The <code class="directive"><ElseIf></code> applies the enclosed
1058 directives if and only if both the given condition evaluates to true and
1059 the most recent <code class="directive"><If></code> or
1060 <code class="directive"><ElseIf></code> section in the same scope has
1061 not been applied. For example: In </p>
1063 <pre class="prettyprint lang-config"><If "-R '10.1.0.0/16'">
1066 <ElseIf "-R '10.0.0.0/8'">
1074 <p>The <code class="directive"><ElseIf></code> would match if
1075 the remote address of a request belongs to the subnet 10.0.0.0/8 but
1076 not to the subnet 10.1.0.0/16.</p>
1081 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
1082 for a complete reference and more examples.</li>
1083 <li><code class="directive"><a href="#if"><If></a></code></li>
1084 <li><code class="directive"><a href="#else"><Else></a></code></li>
1085 <li><a href="../sections.html">How <Directory>, <Location>,
1086 <Files> sections work</a> for an explanation of how these
1087 different sections are combined when a request is received.
1088 <code class="directive"><If></code>,
1089 <code class="directive"><ElseIf></code>, and
1090 <code class="directive"><Else></code> are applied last.</li>
1093 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1094 <div class="directive-section"><h2><a name="EnableMMAP" id="EnableMMAP">EnableMMAP</a> <a name="enablemmap" id="enablemmap">Directive</a></h2>
1095 <table class="directive">
1096 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use memory-mapping to read files during delivery</td></tr>
1097 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableMMAP On|Off</code></td></tr>
1098 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableMMAP On</code></td></tr>
1099 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1100 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1101 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1102 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1104 <p>This directive controls whether the <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use
1105 memory-mapping if it needs to read the contents of a file during
1106 delivery. By default, when the handling of a request requires
1107 access to the data within a file -- for example, when delivering a
1108 server-parsed file using <code class="module"><a href="../mod/mod_include.html">mod_include</a></code> -- Apache httpd
1109 memory-maps the file if the OS supports it.</p>
1111 <p>This memory-mapping sometimes yields a performance improvement.
1112 But in some environments, it is better to disable the memory-mapping
1113 to prevent operational problems:</p>
1116 <li>On some multiprocessor systems, memory-mapping can reduce the
1117 performance of the <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</li>
1118 <li>Deleting or truncating a file while <code class="program"><a href="../programs/httpd.html">httpd</a></code>
1119 has it memory-mapped can cause <code class="program"><a href="../programs/httpd.html">httpd</a></code> to
1120 crash with a segmentation fault.
1124 <p>For server configurations that are vulnerable to these problems,
1125 you should disable memory-mapping of delivered files by specifying:</p>
1127 <pre class="prettyprint lang-config">EnableMMAP Off</pre>
1130 <p>For NFS mounted files, this feature may be disabled explicitly for
1131 the offending files by specifying:</p>
1133 <pre class="prettyprint lang-config"><Directory "/path-to-nfs-files">
1135 </Directory></pre>
1139 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1140 <div class="directive-section"><h2><a name="EnableSendfile" id="EnableSendfile">EnableSendfile</a> <a name="enablesendfile" id="enablesendfile">Directive</a></h2>
1141 <table class="directive">
1142 <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>
1143 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableSendfile On|Off</code></td></tr>
1144 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableSendfile Off</code></td></tr>
1145 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1146 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1147 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1148 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1149 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Default changed to Off in
1150 version 2.3.9.</td></tr>
1152 <p>This directive controls whether <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use the
1153 sendfile support from the kernel to transmit file contents to the client.
1154 By default, when the handling of a request requires no access
1155 to the data within a file -- for example, when delivering a
1156 static file -- Apache httpd uses sendfile to deliver the file contents
1157 without ever reading the file if the OS supports it.</p>
1159 <p>This sendfile mechanism avoids separate read and send operations,
1160 and buffer allocations. But on some platforms or within some
1161 filesystems, it is better to disable this feature to avoid
1162 operational problems:</p>
1165 <li>Some platforms may have broken sendfile support that the build
1166 system did not detect, especially if the binaries were built on
1167 another box and moved to such a machine with broken sendfile
1169 <li>On Linux the use of sendfile triggers TCP-checksum
1170 offloading bugs on certain networking cards when using IPv6.</li>
1171 <li>On Linux on Itanium, <code>sendfile</code> may be unable to handle
1172 files over 2GB in size.</li>
1173 <li>With a network-mounted <code class="directive"><a href="#documentroot">DocumentRoot</a></code> (e.g., NFS, SMB, CIFS, FUSE),
1174 the kernel may be unable to serve the network file through
1178 <p>For server configurations that are not vulnerable to these problems,
1179 you may enable this feature by specifying:</p>
1181 <pre class="prettyprint lang-config">EnableSendfile On</pre>
1184 <p>For network mounted files, this feature may be disabled explicitly
1185 for the offending files by specifying:</p>
1187 <pre class="prettyprint lang-config"><Directory "/path-to-nfs-files">
1189 </Directory></pre>
1191 <p>Please note that the per-directory and .htaccess configuration
1192 of <code class="directive">EnableSendfile</code> is not supported by
1193 <code class="module"><a href="../mod/mod_cache_disk.html">mod_cache_disk</a></code>.
1194 Only global definition of <code class="directive">EnableSendfile</code>
1195 is taken into account by the module.
1199 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1200 <div class="directive-section"><h2><a name="Error" id="Error">Error</a> <a name="error" id="error">Directive</a></h2>
1201 <table class="directive">
1202 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Abort configuration parsing with a custom error message</td></tr>
1203 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Error <var>message</var></code></td></tr>
1204 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1205 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1206 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1207 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.3.9 and later</td></tr>
1209 <p>If an error can be detected within the configuration, this
1210 directive can be used to generate a custom error message, and halt
1211 configuration parsing. The typical use is for reporting required
1212 modules which are missing from the configuration.</p>
1214 <pre class="prettyprint lang-config"># Example
1215 # ensure that mod_include is loaded
1216 <IfModule !include_module>
1217 Error "mod_include is required by mod_foo. Load it with LoadModule."
1220 # ensure that exactly one of SSL,NOSSL is defined
1221 <IfDefine SSL>
1222 <IfDefine NOSSL>
1223 Error "Both SSL and NOSSL are defined. Define only one of them."
1226 <IfDefine !SSL>
1227 <IfDefine !NOSSL>
1228 Error "Either SSL or NOSSL must be defined."
1230 </IfDefine></pre>
1235 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1236 <div class="directive-section"><h2><a name="ErrorDocument" id="ErrorDocument">ErrorDocument</a> <a name="errordocument" id="errordocument">Directive</a></h2>
1237 <table class="directive">
1238 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>What the server will return to the client
1239 in case of an error</td></tr>
1240 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ErrorDocument <var>error-code</var> <var>document</var></code></td></tr>
1241 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1242 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1243 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1244 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1246 <p>In the event of a problem or error, Apache httpd can be configured
1247 to do one of four things,</p>
1250 <li>output a simple hardcoded error message</li>
1252 <li>output a customized message</li>
1254 <li>internally redirect to a local <var>URL-path</var> to handle the
1257 <li>redirect to an external <var>URL</var> to handle the
1261 <p>The first option is the default, while options 2-4 are
1262 configured using the <code class="directive">ErrorDocument</code>
1263 directive, which is followed by the HTTP response code and a URL
1264 or a message. Apache httpd will sometimes offer additional information
1265 regarding the problem/error.</p>
1267 <p>URLs can begin with a slash (/) for local web-paths (relative
1268 to the <code class="directive"><a href="#documentroot">DocumentRoot</a></code>), or be a
1269 full URL which the client can resolve. Alternatively, a message
1270 can be provided to be displayed by the browser. Examples:</p>
1272 <pre class="prettyprint lang-config">ErrorDocument 500 http://foo.example.com/cgi-bin/tester
1273 ErrorDocument 404 /cgi-bin/bad_urls.pl
1274 ErrorDocument 401 /subscription_info.html
1275 ErrorDocument 403 "Sorry can't allow you access today"
1276 ErrorDocument 403 Forbidden!</pre>
1279 <p>Additionally, the special value <code>default</code> can be used
1280 to specify Apache httpd's simple hardcoded message. While not required
1281 under normal circumstances, <code>default</code> will restore
1282 Apache httpd's simple hardcoded message for configurations that would
1283 otherwise inherit an existing <code class="directive">ErrorDocument</code>.</p>
1285 <pre class="prettyprint lang-config">ErrorDocument 404 /cgi-bin/bad_urls.pl
1287 <Directory /web/docs>
1288 ErrorDocument 404 default
1289 </Directory></pre>
1292 <p>Note that when you specify an <code class="directive">ErrorDocument</code>
1293 that points to a remote URL (ie. anything with a method such as
1294 <code>http</code> in front of it), Apache HTTP Server will send a redirect to the
1295 client to tell it where to find the document, even if the
1296 document ends up being on the same server. This has several
1297 implications, the most important being that the client will not
1298 receive the original error status code, but instead will
1299 receive a redirect status code. This in turn can confuse web
1300 robots and other clients which try to determine if a URL is
1301 valid using the status code. In addition, if you use a remote
1302 URL in an <code>ErrorDocument 401</code>, the client will not
1303 know to prompt the user for a password since it will not
1304 receive the 401 status code. Therefore, <strong>if you use an
1305 <code>ErrorDocument 401</code> directive then it must refer to a local
1306 document.</strong></p>
1308 <p>Microsoft Internet Explorer (MSIE) will by default ignore
1309 server-generated error messages when they are "too small" and substitute
1310 its own "friendly" error messages. The size threshold varies depending on
1311 the type of error, but in general, if you make your error document
1312 greater than 512 bytes, then MSIE will show the server-generated
1313 error rather than masking it. More information is available in
1314 Microsoft Knowledge Base article <a href="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q294807">Q294807</a>.</p>
1316 <p>Although most error messages can be overridden, there are certain
1317 circumstances where the internal messages are used regardless of the
1318 setting of <code class="directive"><a href="#errordocument">ErrorDocument</a></code>. In
1319 particular, if a malformed request is detected, normal request processing
1320 will be immediately halted and the internal error message returned.
1321 This is necessary to guard against security problems caused by
1324 <p>If you are using mod_proxy, you may wish to enable
1325 <code class="directive"><a href="../mod/mod_proxy.html#proxyerroroverride">ProxyErrorOverride</a></code> so that you can provide
1326 custom error messages on behalf of your Origin servers. If you don't enable ProxyErrorOverride,
1327 Apache httpd will not generate custom error documents for proxied content.</p>
1331 <li><a href="../custom-error.html">documentation of
1332 customizable responses</a></li>
1335 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1336 <div class="directive-section"><h2><a name="ErrorLog" id="ErrorLog">ErrorLog</a> <a name="errorlog" id="errorlog">Directive</a></h2>
1337 <table class="directive">
1338 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Location where the server will log errors</td></tr>
1339 <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>
1340 <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>
1341 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1342 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1343 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1345 <p>The <code class="directive">ErrorLog</code> directive sets the name of
1346 the file to which the server will log any errors it encounters. If
1347 the <var>file-path</var> is not absolute then it is assumed to be
1348 relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1350 <pre class="prettyprint lang-config">ErrorLog "/var/log/httpd/error_log"</pre>
1353 <p>If the <var>file-path</var>
1354 begins with a pipe character "<code>|</code>" then it is assumed to be a
1355 command to spawn to handle the error log.</p>
1357 <pre class="prettyprint lang-config">ErrorLog "|/usr/local/bin/httpd_errors"</pre>
1360 <p>See the notes on <a href="../logs.html#piped">piped logs</a> for
1361 more information.</p>
1363 <p>Using <code>syslog</code> instead of a filename enables logging
1364 via syslogd(8) if the system supports it and if <code class="module"><a href="../mod/mod_syslog.html">mod_syslog</a></code>
1365 is loaded. The default is to use syslog facility <code>local7</code>,
1366 but you can override this by using the <code>syslog:<var>facility</var></code>
1367 syntax where <var>facility</var> can be one of the names usually documented in
1368 syslog(1). The facility is effectively global, and if it is changed
1369 in individual virtual hosts, the final facility specified affects the
1372 <pre class="prettyprint lang-config">ErrorLog syslog:user</pre>
1375 <p>Additional modules can provide their own ErrorLog providers. The syntax
1376 is similar to <code>syslog</code> example above.</p>
1378 <p>SECURITY: See the <a href="../misc/security_tips.html#serverroot">security tips</a>
1379 document for details on why your security could be compromised
1380 if the directory where log files are stored is writable by
1381 anyone other than the user that starts the server.</p>
1382 <div class="warning"><h3>Note</h3>
1383 <p>When entering a file path on non-Unix platforms, care should be taken
1384 to make sure that only forward slashes are used even though the platform
1385 may allow the use of back slashes. In general it is a good idea to always
1386 use forward slashes throughout the configuration files.</p>
1391 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1392 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1395 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1396 <div class="directive-section"><h2><a name="ErrorLogFormat" id="ErrorLogFormat">ErrorLogFormat</a> <a name="errorlogformat" id="errorlogformat">Directive</a></h2>
1397 <table class="directive">
1398 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Format specification for error log entries</td></tr>
1399 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code> ErrorLogFormat [connection|request] <var>format</var></code></td></tr>
1400 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1401 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1402 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1403 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.3.9 and later</td></tr>
1405 <p><code class="directive">ErrorLogFormat</code> allows to specify what
1406 supplementary information is logged in the error log in addition to the
1407 actual log message.</p>
1409 <pre class="prettyprint lang-config">#Simple example
1410 ErrorLogFormat "[%t] [%l] [pid %P] %F: %E: [client %a] %M"</pre>
1413 <p>Specifying <code>connection</code> or <code>request</code> as first
1414 parameter allows to specify additional formats, causing additional
1415 information to be logged when the first message is logged for a specific
1416 connection or request, respectively. This additional information is only
1417 logged once per connection/request. If a connection or request is processed
1418 without causing any log message, the additional information is not logged
1421 <p>It can happen that some format string items do not produce output. For
1422 example, the Referer header is only present if the log message is
1423 associated to a request and the log message happens at a time when the
1424 Referer header has already been read from the client. If no output is
1425 produced, the default behavior is to delete everything from the preceding
1426 space character to the next space character. This means the log line is
1427 implicitly divided into fields on non-whitespace to whitespace transitions.
1428 If a format string item does not produce output, the whole field is
1429 omitted. For example, if the remote address <code>%a</code> in the log
1430 format <code>[%t] [%l] [%a] %M </code> is not available, the surrounding
1431 brackets are not logged either. Space characters can be escaped with a
1432 backslash to prevent them from delimiting a field. The combination '% '
1433 (percent space) is a zero-width field delimiter that does not produce any
1436 <p>The above behavior can be changed by adding modifiers to the format
1437 string item. A <code>-</code> (minus) modifier causes a minus to be logged if the
1438 respective item does not produce any output. In once-per-connection/request
1439 formats, it is also possible to use the <code>+</code> (plus) modifier. If an
1440 item with the plus modifier does not produce any output, the whole line is
1443 <p>A number as modifier can be used to assign a log severity level to a
1444 format item. The item will only be logged if the severity of the log
1445 message is not higher than the specified log severity level. The number can
1446 range from 1 (alert) over 4 (warn) and 7 (debug) to 15 (trace8).</p>
1448 <p>For example, here's what would happen if you added modifiers to
1449 the <code>%{Referer}i</code> token, which logs the
1450 <code>Referer</code> request header.</p>
1452 <table class="bordered"><tr class="header"><th>Modified Token</th><th>Meaning</th></tr>
1454 <td><code>%-{Referer}i</code></td>
1455 <td>Logs a <code>-</code> if <code>Referer</code> is not set.</td>
1458 <td><code>%+{Referer}i</code></td>
1459 <td>Omits the entire line if <code>Referer</code> is not set.</td>
1462 <td><code>%4{Referer}i</code></td>
1463 <td>Logs the <code>Referer</code> only if the log message severity
1464 is higher than 4.</td>
1468 <p>Some format string items accept additional parameters in braces.</p>
1470 <table class="bordered"><tr class="header"><th>Format String</th> <th>Description</th></tr>
1471 <tr><td><code>%%</code></td>
1472 <td>The percent sign</td></tr>
1473 <tr class="odd"><td><code>%a</code></td>
1474 <td>Client IP address and port of the request</td></tr>
1475 <tr><td><code>%{c}a</code></td>
1476 <td>Underlying peer IP address and port of the connection (see the
1477 <code class="module"><a href="../mod/mod_remoteip.html">mod_remoteip</a></code> module)</td></tr>
1478 <tr class="odd"><td><code>%A</code></td>
1479 <td>Local IP-address and port</td></tr>
1480 <tr><td><code>%{<em>name</em>}e</code></td>
1481 <td>Request environment variable <em>name</em></td></tr>
1482 <tr class="odd"><td><code>%E</code></td>
1483 <td>APR/OS error status code and string</td></tr>
1484 <tr><td><code>%F</code></td>
1485 <td>Source file name and line number of the log call</td></tr>
1486 <tr class="odd"><td><code>%{<em>name</em>}i</code></td>
1487 <td>Request header <em>name</em></td></tr>
1488 <tr><td><code>%k</code></td>
1489 <td>Number of keep-alive requests on this connection</td></tr>
1490 <tr class="odd"><td><code>%l</code></td>
1491 <td>Loglevel of the message</td></tr>
1492 <tr><td><code>%L</code></td>
1493 <td>Log ID of the request</td></tr>
1494 <tr class="odd"><td><code>%{c}L</code></td>
1495 <td>Log ID of the connection</td></tr>
1496 <tr><td><code>%{C}L</code></td>
1497 <td>Log ID of the connection if used in connection scope, empty otherwise</td></tr>
1498 <tr class="odd"><td><code>%m</code></td>
1499 <td>Name of the module logging the message</td></tr>
1500 <tr><td><code>%M</code></td>
1501 <td>The actual log message</td></tr>
1502 <tr class="odd"><td><code>%{<em>name</em>}n</code></td>
1503 <td>Request note <em>name</em></td></tr>
1504 <tr><td><code>%P</code></td>
1505 <td>Process ID of current process</td></tr>
1506 <tr class="odd"><td><code>%T</code></td>
1507 <td>Thread ID of current thread</td></tr>
1508 <tr><td><code>%{g}T</code></td>
1509 <td>System unique thread ID of current thread (the same ID as
1510 displayed by e.g. <code>top</code>; currently Linux only)</td></tr>
1511 <tr class="odd"><td><code>%t</code></td>
1512 <td>The current time</td></tr>
1513 <tr><td><code>%{u}t</code></td>
1514 <td>The current time including micro-seconds</td></tr>
1515 <tr class="odd"><td><code>%{cu}t</code></td>
1516 <td>The current time in compact ISO 8601 format, including
1517 micro-seconds</td></tr>
1518 <tr><td><code>%v</code></td>
1519 <td>The canonical <code class="directive"><a href="#servername">ServerName</a></code>
1520 of the current server.</td></tr>
1521 <tr class="odd"><td><code>%V</code></td>
1522 <td>The server name of the server serving the request according to the
1523 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code>
1525 <tr><td><code>\ </code> (backslash space)</td>
1526 <td>Non-field delimiting space</td></tr>
1527 <tr class="odd"><td><code>% </code> (percent space)</td>
1528 <td>Field delimiter (no output)</td></tr>
1531 <p>The log ID format <code>%L</code> produces a unique id for a connection
1532 or request. This can be used to correlate which log lines belong to the
1533 same connection or request, which request happens on which connection.
1534 A <code>%L</code> format string is also available in
1535 <code class="module"><a href="../mod/mod_log_config.html">mod_log_config</a></code>, to allow to correlate access log entries
1536 with error log lines. If <code class="module"><a href="../mod/mod_unique_id.html">mod_unique_id</a></code> is loaded, its
1537 unique id will be used as log ID for requests.</p>
1539 <pre class="prettyprint lang-config">#Example (default format for threaded MPMs)
1540 ErrorLogFormat "[%{u}t] [%-m:%l] [pid %P:tid %T] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"</pre>
1543 <p>This would result in error messages such as:</p>
1545 <div class="example"><p><code>
1546 [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
1549 <p>Notice that, as discussed above, some fields are omitted
1550 entirely because they are not defined.</p>
1552 <pre class="prettyprint lang-config">#Example (similar to the 2.2.x format)
1553 ErrorLogFormat "[%t] [%l] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"</pre>
1556 <pre class="prettyprint lang-config">#Advanced example with request/connection log IDs
1557 ErrorLogFormat "[%{uc}t] [%-m:%-l] [R:%L] [C:%{C}L] %7F: %E: %M"
1558 ErrorLogFormat request "[%{uc}t] [R:%L] Request %k on C:%{c}L pid:%P tid:%T"
1559 ErrorLogFormat request "[%{uc}t] [R:%L] UA:'%+{User-Agent}i'"
1560 ErrorLogFormat request "[%{uc}t] [R:%L] Referer:'%+{Referer}i'"
1561 ErrorLogFormat connection "[%{uc}t] [C:%{c}L] local\ %a remote\ %A"</pre>
1567 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
1568 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1569 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1572 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1573 <div class="directive-section"><h2><a name="ExtendedStatus" id="ExtendedStatus">ExtendedStatus</a> <a name="extendedstatus" id="extendedstatus">Directive</a></h2>
1574 <table class="directive">
1575 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Keep track of extended status information for each
1577 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ExtendedStatus On|Off</code></td></tr>
1578 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ExtendedStatus Off[*]</code></td></tr>
1579 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
1580 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1581 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1583 <p>This option tracks additional data per worker about the
1584 currently executing request, and a utilization summary; you
1585 can see these variables during runtime by configuring
1586 <code class="module"><a href="../mod/mod_status.html">mod_status</a></code>. Note that other modules may
1587 rely on this scoreboard.</p>
1589 <p>This setting applies to the entire server, and cannot be
1590 enabled or disabled on a virtualhost-by-virtualhost basis.
1591 The collection of extended status information can slow down
1592 the server. Also note that this setting cannot be changed
1593 during a graceful restart.</p>
1596 <p>Note that loading <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> will change
1597 the default behavior to ExtendedStatus On, while other
1598 third party modules may do the same. Such modules rely on
1599 collecting detailed information about the state of all workers.
1600 The default is changed by <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> beginning
1601 with version 2.3.6; the previous default was always Off.</p>
1606 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1607 <div class="directive-section"><h2><a name="FileETag" id="FileETag">FileETag</a> <a name="fileetag" id="fileetag">Directive</a></h2>
1608 <table class="directive">
1609 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>File attributes used to create the ETag
1610 HTTP response header for static files</td></tr>
1611 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>FileETag <var>component</var> ...</code></td></tr>
1612 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>FileETag MTime Size</code></td></tr>
1613 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1614 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1615 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1616 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1617 <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
1621 The <code class="directive">FileETag</code> directive configures the file
1622 attributes that are used to create the <code>ETag</code> (entity
1623 tag) response header field when the document is based on a static file.
1624 (The <code>ETag</code> value is used in cache management to save
1625 network bandwidth.) The
1626 <code class="directive">FileETag</code> directive allows you to choose
1627 which of these -- if any -- should be used. The recognized keywords are:
1631 <dt><strong>INode</strong></dt>
1632 <dd>The file's i-node number will be included in the calculation</dd>
1633 <dt><strong>MTime</strong></dt>
1634 <dd>The date and time the file was last modified will be included</dd>
1635 <dt><strong>Size</strong></dt>
1636 <dd>The number of bytes in the file will be included</dd>
1637 <dt><strong>All</strong></dt>
1638 <dd>All available fields will be used. This is equivalent to:
1639 <pre class="prettyprint lang-config">FileETag INode MTime Size</pre>
1641 <dt><strong>None</strong></dt>
1642 <dd>If a document is file-based, no <code>ETag</code> field will be
1643 included in the response</dd>
1646 <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
1647 keywords may be prefixed with either <code>+</code> or <code>-</code>,
1648 which allow changes to be made to the default setting inherited
1649 from a broader scope. Any keyword appearing without such a prefix
1650 immediately and completely cancels the inherited setting.</p>
1652 <p>If a directory's configuration includes
1653 <code>FileETag INode MTime Size</code>, and a
1654 subdirectory's includes <code>FileETag -INode</code>,
1655 the setting for that subdirectory (which will be inherited by
1656 any sub-subdirectories that don't override it) will be equivalent to
1657 <code>FileETag MTime Size</code>.</p>
1658 <div class="warning"><h3>Warning</h3>
1659 Do not change the default for directories or locations that have WebDAV
1660 enabled and use <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> as a storage provider.
1661 <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> uses <code>MTime Size</code>
1662 as a fixed format for <code>ETag</code> comparisons on conditional requests.
1663 These conditional requests will break if the <code>ETag</code> format is
1664 changed via <code class="directive">FileETag</code>.
1666 <div class="note"><h3>Server Side Includes</h3>
1667 An ETag is not generated for responses parsed by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>,
1668 since the response entity can change without a change of the INode, MTime, or Size
1669 of the static file with embedded SSI directives.
1674 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1675 <div class="directive-section"><h2><a name="Files" id="Files"><Files></a> <a name="files" id="files">Directive</a></h2>
1676 <table class="directive">
1677 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to matched
1679 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Files <var>filename</var>> ... </Files></code></td></tr>
1680 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1681 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1682 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1683 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1685 <p>The <code class="directive"><Files></code> directive
1686 limits the scope of the enclosed directives by filename. It is comparable
1687 to the <code class="directive"><a href="#directory"><Directory></a></code>
1688 and <code class="directive"><a href="#location"><Location></a></code>
1689 directives. It should be matched with a <code></Files></code>
1690 directive. The directives given within this section will be applied to
1691 any object with a basename (last component of filename) matching the
1692 specified filename. <code class="directive"><Files></code>
1693 sections are processed in the order they appear in the
1694 configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
1695 <code>.htaccess</code> files are read, but before <code class="directive"><a href="#location"><Location></a></code> sections. Note
1696 that <code class="directive"><Files></code> can be nested
1697 inside <code class="directive"><a href="#directory"><Directory></a></code> sections to restrict the
1698 portion of the filesystem they apply to.</p>
1700 <p>The <var>filename</var> argument should include a filename, or
1701 a wild-card string, where <code>?</code> matches any single character,
1702 and <code>*</code> matches any sequences of characters.</p>
1703 <pre class="prettyprint lang-config"><Files "cat.html">
1704 # Insert stuff that applies to cat.html here
1707 <Files "?at.*">
1708 # This would apply to cat.html, bat.html, hat.php and so on.
1709 </Files></pre>
1711 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
1712 can also be used, with the addition of the
1713 <code>~</code> character. For example:</p>
1715 <pre class="prettyprint lang-config"><Files ~ "\.(gif|jpe?g|png)$">
1717 </Files></pre>
1720 <p>would match most common Internet graphics formats. <code class="directive"><a href="#filesmatch"><FilesMatch></a></code> is preferred,
1723 <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
1724 <code>.htaccess</code> files. This allows users to control access to
1725 their own files, at a file-by-file level.</p>
1730 <li><a href="../sections.html">How <Directory>, <Location>
1731 and <Files> sections work</a> for an explanation of how these
1732 different sections are combined when a request is received</li>
1735 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1736 <div class="directive-section"><h2><a name="FilesMatch" id="FilesMatch"><FilesMatch></a> <a name="filesmatch" id="filesmatch">Directive</a></h2>
1737 <table class="directive">
1738 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to regular-expression matched
1740 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><FilesMatch <var>regex</var>> ... </FilesMatch></code></td></tr>
1741 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1742 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1743 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1744 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1746 <p>The <code class="directive"><FilesMatch></code> directive
1747 limits the scope of the enclosed directives by filename, just as the
1748 <code class="directive"><a href="#files"><Files></a></code> directive
1749 does. However, it accepts a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular
1750 expression</a>. For example:</p>
1752 <pre class="prettyprint lang-config"><FilesMatch "\.(gif|jpe?g|png)$">
1754 </FilesMatch></pre>
1757 <p>would match most common Internet graphics formats.</p>
1759 <p>From 2.4.8 onwards, named groups and backreferences are captured and
1760 written to the environment with the corresponding name prefixed with
1761 "MATCH_" and in upper case. This allows elements of files to be referenced
1762 from within <a href="../expr.html">expressions</a> and modules like
1763 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
1764 (unnamed) backreferences are ignored. Use named groups instead.</p>
1766 <pre class="prettyprint lang-config"><FilesMatch ^(?<sitename>[^/]+)>
1767 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
1768 </FilesMatch></pre>
1773 <li><a href="../sections.html">How <Directory>, <Location>
1774 and <Files> sections work</a> for an explanation of how these
1775 different sections are combined when a request is received</li>
1778 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1779 <div class="directive-section"><h2><a name="ForceType" id="ForceType">ForceType</a> <a name="forcetype" id="forcetype">Directive</a></h2>
1780 <table class="directive">
1781 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be served with the specified
1782 media type in the HTTP Content-Type header field</td></tr>
1783 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ForceType <var>media-type</var>|None</code></td></tr>
1784 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
1785 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1786 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1787 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1789 <p>When placed into an <code>.htaccess</code> file or a
1790 <code class="directive"><a href="#directory"><Directory></a></code>, or
1791 <code class="directive"><a href="#location"><Location></a></code> or
1792 <code class="directive"><a href="#files"><Files></a></code>
1793 section, this directive forces all matching files to be served
1794 with the content type identification given by
1795 <var>media-type</var>. For example, if you had a directory full of
1796 GIF files, but did not want to label them all with <code>.gif</code>,
1797 you might want to use:</p>
1799 <pre class="prettyprint lang-config">ForceType image/gif</pre>
1802 <p>Note that this directive overrides other indirect media type
1803 associations defined in mime.types or via the
1804 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code>.</p>
1806 <p>You can also override more general
1807 <code class="directive">ForceType</code> settings
1808 by using the value of <code>None</code>:</p>
1810 <pre class="prettyprint lang-config"># force all files to be image/gif:
1811 <Location /images>
1815 # but normal mime-type associations here:
1816 <Location /images/mixed>
1818 </Location></pre>
1821 <p>This directive primarily overrides the content types generated for
1822 static files served out of the filesystem. For resources other than
1823 static files, where the generator of the response typically specifies
1824 a Content-Type, this directive has no effect.</p>
1828 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1829 <div class="directive-section"><h2><a name="GprofDir" id="GprofDir">GprofDir</a> <a name="gprofdir" id="gprofdir">Directive</a></h2>
1830 <table class="directive">
1831 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory to write gmon.out profiling data to. </td></tr>
1832 <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>
1833 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1834 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1835 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1837 <p>When the server has been compiled with gprof profiling support,
1838 <code class="directive">GprofDir</code> causes <code>gmon.out</code> files to
1839 be written to the specified directory when the process exits. If the
1840 argument ends with a percent symbol ('%'), subdirectories are created
1841 for each process id.</p>
1843 <p>This directive currently only works with the <code class="module"><a href="../mod/prefork.html">prefork</a></code>
1847 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1848 <div class="directive-section"><h2><a name="HostnameLookups" id="HostnameLookups">HostnameLookups</a> <a name="hostnamelookups" id="hostnamelookups">Directive</a></h2>
1849 <table class="directive">
1850 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables DNS lookups on client IP addresses</td></tr>
1851 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>HostnameLookups On|Off|Double</code></td></tr>
1852 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>HostnameLookups Off</code></td></tr>
1853 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1854 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1855 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1857 <p>This directive enables DNS lookups so that host names can be
1858 logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
1859 The value <code>Double</code> refers to doing double-reverse
1860 DNS lookup. That is, after a reverse lookup is performed, a forward
1861 lookup is then performed on that result. At least one of the IP
1862 addresses in the forward lookup must match the original
1863 address. (In "tcpwrappers" terminology this is called
1864 <code>PARANOID</code>.)</p>
1866 <p>Regardless of the setting, when <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code> is
1867 used for controlling access by hostname, a double reverse lookup
1868 will be performed. This is necessary for security. Note that the
1869 result of this double-reverse isn't generally available unless you
1870 set <code>HostnameLookups Double</code>. For example, if only
1871 <code>HostnameLookups On</code> and a request is made to an object
1872 that is protected by hostname restrictions, regardless of whether
1873 the double-reverse fails or not, CGIs will still be passed the
1874 single-reverse result in <code>REMOTE_HOST</code>.</p>
1876 <p>The default is <code>Off</code> in order to save the network
1877 traffic for those sites that don't truly need the reverse
1878 lookups done. It is also better for the end users because they
1879 don't have to suffer the extra latency that a lookup entails.
1880 Heavily loaded sites should leave this directive
1881 <code>Off</code>, since DNS lookups can take considerable
1882 amounts of time. The utility <code class="program"><a href="../programs/logresolve.html">logresolve</a></code>, compiled by
1883 default to the <code>bin</code> subdirectory of your installation
1884 directory, can be used to look up host names from logged IP addresses
1887 <p>Finally, if you have <a href="mod_authz_host.html#reqhost">hostname-based Require
1888 directives</a>, a hostname lookup will be performed regardless of
1889 the setting of <code>HostnameLookups</code>.</p>
1892 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1893 <div class="directive-section"><h2><a name="If" id="If"><If></a> <a name="if" id="if">Directive</a></h2>
1894 <table class="directive">
1895 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is
1896 satisfied by a request at runtime</td></tr>
1897 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><If <var>expression</var>> ... </If></code></td></tr>
1898 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1899 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1900 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1901 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1903 <p>The <code class="directive"><If></code> directive
1904 evaluates an expression at runtime, and applies the enclosed
1905 directives if and only if the expression evaluates to true.
1908 <pre class="prettyprint lang-config"><If "-z req('Host')"></pre>
1911 <p>would match HTTP/1.0 requests without a <var>Host:</var> header.
1912 Expressions may contain various shell-like operators for string
1913 comparison (<code>=</code>, <code>!=</code>, <code><</code>, ...),
1914 integer comparison (<code>-eq</code>, <code>-ne</code>, ...),
1915 and others (<code>-n</code>, <code>-z</code>, <code>-f</code>, ...).
1916 It is also possible to use regular expressions, </p>
1918 <pre class="prettyprint lang-config"><If "%{QUERY_STRING} =~ /(delete|commit)=.*?elem/"></pre>
1921 <p>shell-like pattern matches and many other operations. These operations
1922 can be done on request headers (<code>req</code>), environment variables
1923 (<code>env</code>), and a large number of other properties. The full
1924 documentation is available in <a href="../expr.html">Expressions in
1925 Apache HTTP Server</a>.</p>
1927 <p>Only directives that support the <a href="directive-dict.html#Context">directory context</a> can be used within this configuration section.</p>
1932 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
1933 for a complete reference and more examples.</li>
1934 <li><code class="directive"><a href="#elseif"><ElseIf></a></code></li>
1935 <li><code class="directive"><a href="#else"><Else></a></code></li>
1936 <li><a href="../sections.html">How <Directory>, <Location>,
1937 <Files> sections work</a> for an explanation of how these
1938 different sections are combined when a request is received.
1939 <code class="directive"><If></code>,
1940 <code class="directive"><ElseIf></code>, and
1941 <code class="directive"><Else></code> are applied last.</li>
1944 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1945 <div class="directive-section"><h2><a name="IfDefine" id="IfDefine"><IfDefine></a> <a name="ifdefine" id="ifdefine">Directive</a></h2>
1946 <table class="directive">
1947 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that will be processed only
1948 if a test is true at startup</td></tr>
1949 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfDefine [!]<var>parameter-name</var>> ...
1950 </IfDefine></code></td></tr>
1951 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1952 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1953 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1954 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1956 <p>The <code><IfDefine <var>test</var>>...</IfDefine>
1957 </code> section is used to mark directives that are conditional. The
1958 directives within an <code class="directive"><IfDefine></code>
1959 section are only processed if the <var>test</var> is true. If <var>
1960 test</var> is false, everything between the start and end markers is
1963 <p>The <var>test</var> in the <code class="directive"><IfDefine></code> section directive can be one of two forms:</p>
1966 <li><var>parameter-name</var></li>
1968 <li><code>!</code><var>parameter-name</var></li>
1971 <p>In the former case, the directives between the start and end
1972 markers are only processed if the parameter named
1973 <var>parameter-name</var> is defined. The second format reverses
1974 the test, and only processes the directives if
1975 <var>parameter-name</var> is <strong>not</strong> defined.</p>
1977 <p>The <var>parameter-name</var> argument is a define as given on the
1978 <code class="program"><a href="../programs/httpd.html">httpd</a></code> command line via <code>-D<var>parameter</var>
1979 </code> at the time the server was started or by the <code class="directive"><a href="#define">Define</a></code> directive.</p>
1981 <p><code class="directive"><IfDefine></code> sections are
1982 nest-able, which can be used to implement simple
1983 multiple-parameter tests. Example:</p>
1985 <div class="example"><p><code>httpd -DReverseProxy -DUseCache -DMemCache ...</code></p></div>
1986 <pre class="prettyprint lang-config"><IfDefine ReverseProxy>
1987 LoadModule proxy_module modules/mod_proxy.so
1988 LoadModule proxy_http_module modules/mod_proxy_http.so
1989 <IfDefine UseCache>
1990 LoadModule cache_module modules/mod_cache.so
1991 <IfDefine MemCache>
1992 LoadModule mem_cache_module modules/mod_mem_cache.so
1994 <IfDefine !MemCache>
1995 LoadModule cache_disk_module modules/mod_cache_disk.so
1998 </IfDefine></pre>
2002 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2003 <div class="directive-section"><h2><a name="IfModule" id="IfModule"><IfModule></a> <a name="ifmodule" id="ifmodule">Directive</a></h2>
2004 <table class="directive">
2005 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that are processed conditional on the
2006 presence or absence of a specific module</td></tr>
2007 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfModule [!]<var>module-file</var>|<var>module-identifier</var>> ...
2008 </IfModule></code></td></tr>
2009 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2010 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2011 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2012 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2014 <p>The <code><IfModule <var>test</var>>...</IfModule></code>
2015 section is used to mark directives that are conditional on the presence of
2016 a specific module. The directives within an <code class="directive"><IfModule></code> section are only processed if the <var>test</var>
2017 is true. If <var>test</var> is false, everything between the start and
2018 end markers is ignored.</p>
2020 <p>The <var>test</var> in the <code class="directive"><IfModule></code> section directive can be one of two forms:</p>
2023 <li><var>module</var></li>
2025 <li>!<var>module</var></li>
2028 <p>In the former case, the directives between the start and end
2029 markers are only processed if the module named <var>module</var>
2030 is included in Apache httpd -- either compiled in or
2031 dynamically loaded using <code class="directive"><a href="../mod/mod_so.html#loadmodule">LoadModule</a></code>. The second format reverses the test,
2032 and only processes the directives if <var>module</var> is
2033 <strong>not</strong> included.</p>
2035 <p>The <var>module</var> argument can be either the module identifier or
2036 the file name of the module, at the time it was compiled. For example,
2037 <code>rewrite_module</code> is the identifier and
2038 <code>mod_rewrite.c</code> is the file name. If a module consists of
2039 several source files, use the name of the file containing the string
2040 <code>STANDARD20_MODULE_STUFF</code>.</p>
2042 <p><code class="directive"><IfModule></code> sections are
2043 nest-able, which can be used to implement simple multiple-module
2046 <div class="note">This section should only be used if you need to have one
2047 configuration file that works whether or not a specific module
2048 is available. In normal operation, directives need not be
2049 placed in <code class="directive"><IfModule></code>
2053 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2054 <div class="directive-section"><h2><a name="Include" id="Include">Include</a> <a name="include" id="include">Directive</a></h2>
2055 <table class="directive">
2056 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2057 the server configuration files</td></tr>
2058 <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>
2059 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2060 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2061 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2062 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Directory
2063 wildcard matching available in 2.3.6 and later</td></tr>
2065 <p>This directive allows inclusion of other configuration files
2066 from within the server configuration files.</p>
2068 <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used
2069 in the filename or directory parts of the path to include several files
2070 at once, in alphabetical order. In addition, if
2071 <code class="directive">Include</code> points to a directory, rather than a file,
2072 Apache httpd will read all files in that directory and any subdirectory.
2073 However, including entire directories is not recommended, because it is
2074 easy to accidentally leave temporary files in a directory that can cause
2075 <code class="program"><a href="../programs/httpd.html">httpd</a></code> to fail. Instead, we encourage you to use the
2076 wildcard syntax shown below, to include files that match a particular
2077 pattern, such as *.conf, for example.</p>
2079 <p>The <code class="directive"><a href="#include">Include</a></code> directive will
2080 <strong>fail with an error</strong> if a wildcard expression does not
2081 match any file. The <code class="directive"><a href="#includeoptional">IncludeOptional</a></code>
2082 directive can be used if non-matching wildcards should be ignored.</p>
2084 <p>The file path specified may be an absolute path, or may be relative
2085 to the <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory.</p>
2089 <pre class="prettyprint lang-config">Include /usr/local/apache2/conf/ssl.conf
2090 Include /usr/local/apache2/conf/vhosts/*.conf</pre>
2093 <p>Or, providing paths relative to your <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory:</p>
2095 <pre class="prettyprint lang-config">Include conf/ssl.conf
2096 Include conf/vhosts/*.conf</pre>
2099 <p>Wildcards may be included in the directory or file portion of the
2100 path. This example will fail if there is no subdirectory in conf/vhosts
2101 that contains at least one *.conf file:</p>
2103 <pre class="prettyprint lang-config">Include conf/vhosts/*/*.conf</pre>
2106 <p>Alternatively, the following command will just be ignored in case of
2107 missing files or directories:</p>
2109 <pre class="prettyprint lang-config">IncludeOptional conf/vhosts/*/*.conf</pre>
2115 <li><code class="directive"><a href="#includeoptional">IncludeOptional</a></code></li>
2116 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2119 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2120 <div class="directive-section"><h2><a name="IncludeOptional" id="IncludeOptional">IncludeOptional</a> <a name="includeoptional" id="includeoptional">Directive</a></h2>
2121 <table class="directive">
2122 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2123 the server configuration files</td></tr>
2124 <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>
2125 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2126 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2127 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2128 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in 2.3.6 and later</td></tr>
2130 <p>This directive allows inclusion of other configuration files
2131 from within the server configuration files. It works identically to the
2132 <code class="directive"><a href="#include">Include</a></code> directive, with the
2133 exception that if wildcards do not match any file or directory, the
2134 <code class="directive"><a href="#includeoptional">IncludeOptional</a></code> directive will be
2135 silently ignored instead of causing an error.</p>
2139 <li><code class="directive"><a href="#include">Include</a></code></li>
2140 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2143 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2144 <div class="directive-section"><h2><a name="KeepAlive" id="KeepAlive">KeepAlive</a> <a name="keepalive" id="keepalive">Directive</a></h2>
2145 <table class="directive">
2146 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables HTTP persistent connections</td></tr>
2147 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAlive On|Off</code></td></tr>
2148 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAlive On</code></td></tr>
2149 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2150 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2151 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2153 <p>The Keep-Alive extension to HTTP/1.0 and the persistent
2154 connection feature of HTTP/1.1 provide long-lived HTTP sessions
2155 which allow multiple requests to be sent over the same TCP
2156 connection. In some cases this has been shown to result in an
2157 almost 50% speedup in latency times for HTML documents with
2158 many images. To enable Keep-Alive connections, set
2159 <code>KeepAlive On</code>.</p>
2161 <p>For HTTP/1.0 clients, Keep-Alive connections will only be
2162 used if they are specifically requested by a client. In
2163 addition, a Keep-Alive connection with an HTTP/1.0 client can
2164 only be used when the length of the content is known in
2165 advance. This implies that dynamic content such as CGI output,
2166 SSI pages, and server-generated directory listings will
2167 generally not use Keep-Alive connections to HTTP/1.0 clients.
2168 For HTTP/1.1 clients, persistent connections are the default
2169 unless otherwise specified. If the client requests it, chunked
2170 encoding will be used in order to send content of unknown
2171 length over persistent connections.</p>
2173 <p>When a client uses a Keep-Alive connection it will be counted
2174 as a single "request" for the <code class="directive"><a href="../mod/mpm_common.html#maxconnectionsperchild">MaxConnectionsPerChild</a></code> directive, regardless
2175 of how many requests are sent using the connection.</p>
2179 <li><code class="directive"><a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></code></li>
2182 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2183 <div class="directive-section"><h2><a name="KeepAliveTimeout" id="KeepAliveTimeout">KeepAliveTimeout</a> <a name="keepalivetimeout" id="keepalivetimeout">Directive</a></h2>
2184 <table class="directive">
2185 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for subsequent
2186 requests on a persistent connection</td></tr>
2187 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAliveTimeout <var>num</var>[ms]</code></td></tr>
2188 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAliveTimeout 5</code></td></tr>
2189 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2190 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2191 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2192 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Specifying a value in milliseconds is available in
2193 Apache httpd 2.3.2 and later</td></tr>
2195 <p>The number of seconds Apache httpd will wait for a subsequent
2196 request before closing the connection. By adding a postfix of ms the
2197 timeout can be also set in milliseconds. Once a request has been
2198 received, the timeout value specified by the
2199 <code class="directive"><a href="#timeout">Timeout</a></code> directive applies.</p>
2201 <p>Setting <code class="directive">KeepAliveTimeout</code> to a high value
2202 may cause performance problems in heavily loaded servers. The
2203 higher the timeout, the more server processes will be kept
2204 occupied waiting on connections with idle clients.</p>
2206 <p>In a name-based virtual host context, the value of the first
2207 defined virtual host best matching the local IP and port will be used.</p>
2210 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2211 <div class="directive-section"><h2><a name="Limit" id="Limit"><Limit></a> <a name="limit" id="limit">Directive</a></h2>
2212 <table class="directive">
2213 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict enclosed access controls to only certain HTTP
2215 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Limit <var>method</var> [<var>method</var>] ... > ...
2216 </Limit></code></td></tr>
2217 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2218 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2219 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2220 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2222 <p>Access controls are normally effective for
2223 <strong>all</strong> access methods, and this is the usual
2224 desired behavior. <strong>In the general case, access control
2225 directives should not be placed within a
2226 <code class="directive"><Limit></code> section.</strong></p>
2228 <p>The purpose of the <code class="directive"><Limit></code>
2229 directive is to restrict the effect of the access controls to the
2230 nominated HTTP methods. For all other methods, the access
2231 restrictions that are enclosed in the <code class="directive"><Limit></code> bracket <strong>will have no
2232 effect</strong>. The following example applies the access control
2233 only to the methods <code>POST</code>, <code>PUT</code>, and
2234 <code>DELETE</code>, leaving all other methods unprotected:</p>
2236 <pre class="prettyprint lang-config"><Limit POST PUT DELETE>
2238 </Limit></pre>
2241 <p>The method names listed can be one or more of: <code>GET</code>,
2242 <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
2243 <code>CONNECT</code>, <code>OPTIONS</code>,
2244 <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
2245 <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
2246 <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
2247 case-sensitive.</strong> If <code>GET</code> is used it will also
2248 restrict <code>HEAD</code> requests. The <code>TRACE</code> method
2249 cannot be limited (see <code class="directive"><a href="#traceenable">TraceEnable</a></code>).</p>
2251 <div class="warning">A <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section should always be
2252 used in preference to a <code class="directive"><Limit></code>
2253 section when restricting access, since a <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section provides protection
2254 against arbitrary methods.</div>
2256 <p>The <code class="directive"><Limit></code> and
2257 <code class="directive"><a href="#limitexcept"><LimitExcept></a></code>
2258 directives may be nested. In this case, each successive level of
2259 <code class="directive"><Limit></code> or <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> directives must
2260 further restrict the set of methods to which access controls apply.</p>
2262 <div class="warning">When using
2263 <code class="directive"><Limit></code> or
2264 <code class="directive"><LimitExcept></code> directives with
2265 the <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directive,
2266 note that the first <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code>
2267 to succeed authorizes the request, regardless of the presence of other
2268 <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directives.</div>
2270 <p>For example, given the following configuration, all users will
2271 be authorized for <code>POST</code> requests, and the
2272 <code>Require group editors</code> directive will be ignored
2275 <pre class="prettyprint lang-config"><LimitExcept GET>
2277 </LimitExcept>
2279 Require group editors
2280 </Limit></pre>
2284 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2285 <div class="directive-section"><h2><a name="LimitExcept" id="LimitExcept"><LimitExcept></a> <a name="limitexcept" id="limitexcept">Directive</a></h2>
2286 <table class="directive">
2287 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict access controls to all HTTP methods
2288 except the named ones</td></tr>
2289 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LimitExcept <var>method</var> [<var>method</var>] ... > ...
2290 </LimitExcept></code></td></tr>
2291 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2292 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2293 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2294 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2296 <p><code class="directive"><LimitExcept></code> and
2297 <code></LimitExcept></code> are used to enclose
2298 a group of access control directives which will then apply to any
2299 HTTP access method <strong>not</strong> listed in the arguments;
2300 i.e., it is the opposite of a <code class="directive"><a href="#limit"><Limit></a></code> section and can be used to control
2301 both standard and nonstandard/unrecognized methods. See the
2302 documentation for <code class="directive"><a href="#limit"><Limit></a></code> for more details.</p>
2306 <pre class="prettyprint lang-config"><LimitExcept POST GET>
2308 </LimitExcept></pre>
2313 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2314 <div class="directive-section"><h2><a name="LimitInternalRecursion" id="LimitInternalRecursion">LimitInternalRecursion</a> <a name="limitinternalrecursion" id="limitinternalrecursion">Directive</a></h2>
2315 <table class="directive">
2316 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine maximum number of internal redirects and nested
2317 subrequests</td></tr>
2318 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitInternalRecursion <var>number</var> [<var>number</var>]</code></td></tr>
2319 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitInternalRecursion 10</code></td></tr>
2320 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2321 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2322 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2324 <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
2325 redirects the original request to a CGI script. A subrequest is Apache httpd's
2326 mechanism to find out what would happen for some URI if it were requested.
2327 For example, <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> uses subrequests to look for the
2328 files listed in the <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
2331 <p><code class="directive">LimitInternalRecursion</code> prevents the server
2332 from crashing when entering an infinite loop of internal redirects or
2333 subrequests. Such loops are usually caused by misconfigurations.</p>
2335 <p>The directive stores two different limits, which are evaluated on
2336 per-request basis. The first <var>number</var> is the maximum number of
2337 internal redirects, that may follow each other. The second <var>number</var>
2338 determines, how deep subrequests may be nested. If you specify only one
2339 <var>number</var>, it will be assigned to both limits.</p>
2341 <pre class="prettyprint lang-config">LimitInternalRecursion 5</pre>
2345 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2346 <div class="directive-section"><h2><a name="LimitRequestBody" id="LimitRequestBody">LimitRequestBody</a> <a name="limitrequestbody" id="limitrequestbody">Directive</a></h2>
2347 <table class="directive">
2348 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restricts the total size of the HTTP request body sent
2349 from the client</td></tr>
2350 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestBody <var>bytes</var></code></td></tr>
2351 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestBody 0</code></td></tr>
2352 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2353 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2354 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2355 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2357 <p>This directive specifies the number of <var>bytes</var> from 0
2358 (meaning unlimited) to 2147483647 (2GB) that are allowed in a
2359 request body. See the note below for the limited applicability
2360 to proxy requests.</p>
2362 <p>The <code class="directive">LimitRequestBody</code> directive allows
2363 the user to set a limit on the allowed size of an HTTP request
2364 message body within the context in which the directive is given
2365 (server, per-directory, per-file or per-location). If the client
2366 request exceeds that limit, the server will return an error
2367 response instead of servicing the request. The size of a normal
2368 request message body will vary greatly depending on the nature of
2369 the resource and the methods allowed on that resource. CGI scripts
2370 typically use the message body for retrieving form information.
2371 Implementations of the <code>PUT</code> method will require
2372 a value at least as large as any representation that the server
2373 wishes to accept for that resource.</p>
2375 <p>This directive gives the server administrator greater
2376 control over abnormal client request behavior, which may be
2377 useful for avoiding some forms of denial-of-service
2380 <p>If, for example, you are permitting file upload to a particular
2381 location, and wish to limit the size of the uploaded file to 100K,
2382 you might use the following directive:</p>
2384 <pre class="prettyprint lang-config">LimitRequestBody 102400</pre>
2387 <div class="note"><p>For a full description of how this directive is interpreted by
2388 proxy requests, see the <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> documentation.</p>
2393 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2394 <div class="directive-section"><h2><a name="LimitRequestFields" id="LimitRequestFields">LimitRequestFields</a> <a name="limitrequestfields" id="limitrequestfields">Directive</a></h2>
2395 <table class="directive">
2396 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of HTTP request header fields that
2397 will be accepted from the client</td></tr>
2398 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFields <var>number</var></code></td></tr>
2399 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFields 100</code></td></tr>
2400 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2401 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2402 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2404 <p><var>Number</var> is an integer from 0 (meaning unlimited) to
2405 32767. The default value is defined by the compile-time
2406 constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
2409 <p>The <code class="directive">LimitRequestFields</code> directive allows
2410 the server administrator to modify the limit on the number of
2411 request header fields allowed in an HTTP request. A server needs
2412 this value to be larger than the number of fields that a normal
2413 client request might include. The number of request header fields
2414 used by a client rarely exceeds 20, but this may vary among
2415 different client implementations, often depending upon the extent
2416 to which a user has configured their browser to support detailed
2417 content negotiation. Optional HTTP extensions are often expressed
2418 using request header fields.</p>
2420 <p>This directive gives the server administrator greater
2421 control over abnormal client request behavior, which may be
2422 useful for avoiding some forms of denial-of-service attacks.
2423 The value should be increased if normal clients see an error
2424 response from the server that indicates too many fields were
2425 sent in the request.</p>
2429 <pre class="prettyprint lang-config">LimitRequestFields 50</pre>
2432 <div class="warning"><h3>Warning</h3>
2433 <p> When name-based virtual hosting is used, the value for this
2434 directive is taken from the default (first-listed) virtual host for the
2435 local IP and port combination.</p>
2440 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2441 <div class="directive-section"><h2><a name="LimitRequestFieldSize" id="LimitRequestFieldSize">LimitRequestFieldSize</a> <a name="limitrequestfieldsize" id="limitrequestfieldsize">Directive</a></h2>
2442 <table class="directive">
2443 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of the HTTP request header allowed from the
2445 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFieldSize <var>bytes</var></code></td></tr>
2446 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFieldSize 8190</code></td></tr>
2447 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2448 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2449 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2451 <p>This directive specifies the number of <var>bytes</var>
2452 that will be allowed in an HTTP request header.</p>
2454 <p>The <code class="directive">LimitRequestFieldSize</code> directive
2455 allows the server administrator to set the limit
2456 on the allowed size of an HTTP request header field. A server
2457 needs this value to be large enough to hold any one header field
2458 from a normal client request. The size of a normal request header
2459 field will vary greatly among different client implementations,
2460 often depending upon the extent to which a user has configured
2461 their browser to support detailed content negotiation. SPNEGO
2462 authentication headers can be up to 12392 bytes.</p>
2464 <p>This directive gives the server administrator greater
2465 control over abnormal client request behavior, which may be
2466 useful for avoiding some forms of denial-of-service attacks.</p>
2470 <pre class="prettyprint lang-config">LimitRequestFieldSize 4094</pre>
2473 <div class="note">Under normal conditions, the value should not be changed from
2476 <div class="warning"><h3>Warning</h3>
2477 <p> When name-based virtual hosting is used, the value for this
2478 directive is taken from the default (first-listed) virtual host best
2479 matching the current IP address and port combination.</p>
2483 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2484 <div class="directive-section"><h2><a name="LimitRequestLine" id="LimitRequestLine">LimitRequestLine</a> <a name="limitrequestline" id="limitrequestline">Directive</a></h2>
2485 <table class="directive">
2486 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limit the size of the HTTP request line that will be accepted
2487 from the client</td></tr>
2488 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestLine <var>bytes</var></code></td></tr>
2489 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestLine 8190</code></td></tr>
2490 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2491 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2492 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2494 <p>This directive sets the number of <var>bytes</var> that will be
2495 allowed on the HTTP request-line.</p>
2497 <p>The <code class="directive">LimitRequestLine</code> directive allows
2498 the server administrator to set the limit on the allowed size
2499 of a client's HTTP request-line. Since the request-line consists of the
2500 HTTP method, URI, and protocol version, the
2501 <code class="directive">LimitRequestLine</code> directive places a
2502 restriction on the length of a request-URI allowed for a request
2503 on the server. A server needs this value to be large enough to
2504 hold any of its resource names, including any information that
2505 might be passed in the query part of a <code>GET</code> request.</p>
2507 <p>This directive gives the server administrator greater
2508 control over abnormal client request behavior, which may be
2509 useful for avoiding some forms of denial-of-service attacks.</p>
2513 <pre class="prettyprint lang-config">LimitRequestLine 4094</pre>
2516 <div class="note">Under normal conditions, the value should not be changed from
2517 the default. Also, you can't set this higher than 8190 without
2518 modifying the source and rebuilding.</div>
2520 <div class="warning"><h3>Warning</h3>
2521 <p> When name-based virtual hosting is used, the value for this
2522 directive is taken from the default (first-listed) virtual host best
2523 matching the current IP address and port combination.</p>
2528 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2529 <div class="directive-section"><h2><a name="LimitXMLRequestBody" id="LimitXMLRequestBody">LimitXMLRequestBody</a> <a name="limitxmlrequestbody" id="limitxmlrequestbody">Directive</a></h2>
2530 <table class="directive">
2531 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of an XML-based request body</td></tr>
2532 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitXMLRequestBody <var>bytes</var></code></td></tr>
2533 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitXMLRequestBody 1000000</code></td></tr>
2534 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2535 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2536 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2537 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2539 <p>Limit (in bytes) on maximum size of an XML-based request
2540 body. A value of <code>0</code> will disable any checking.</p>
2544 <pre class="prettyprint lang-config">LimitXMLRequestBody 0</pre>
2549 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2550 <div class="directive-section"><h2><a name="Location" id="Location"><Location></a> <a name="location" id="location">Directive</a></h2>
2551 <table class="directive">
2552 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to matching
2554 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Location
2555 <var>URL-path</var>|<var>URL</var>> ... </Location></code></td></tr>
2556 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2557 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2558 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2560 <p>The <code class="directive"><Location></code> directive
2561 limits the scope of the enclosed directives by URL. It is similar to the
2562 <code class="directive"><a href="#directory"><Directory></a></code>
2563 directive, and starts a subsection which is terminated with a
2564 <code></Location></code> directive. <code class="directive"><Location></code> sections are processed in the
2565 order they appear in the configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
2566 <code>.htaccess</code> files are read, and after the <code class="directive"><a href="#files"><Files></a></code> sections.</p>
2568 <p><code class="directive"><Location></code> sections operate
2569 completely outside the filesystem. This has several consequences.
2570 Most importantly, <code class="directive"><Location></code>
2571 directives should not be used to control access to filesystem
2572 locations. Since several different URLs may map to the same
2573 filesystem location, such access controls may by circumvented.</p>
2575 <p>The enclosed directives will be applied to the request if the path component
2576 of the URL meets <em>any</em> of the following criteria:
2579 <li>The specified location matches exactly the path component of the URL.
2581 <li>The specified location, which ends in a forward slash, is a prefix
2582 of the path component of the URL (treated as a context root).
2584 <li>The specified location, with the addition of a trailing slash, is a
2585 prefix of the path component of the URL (also treated as a context root).
2589 In the example below, where no trailing slash is used, requests to
2590 /private1, /private1/ and /private1/file.txt will have the enclosed
2591 directives applied, but /private1other would not.
2593 <pre class="prettyprint lang-config"><Location /private1>
2595 </Location></pre>
2598 In the example below, where a trailing slash is used, requests to
2599 /private2/ and /private2/file.txt will have the enclosed
2600 directives applied, but /private2 and /private2other would not.
2602 <pre class="prettyprint lang-config"><Location /private2<em>/</em>>
2604 </Location></pre>
2607 <div class="note"><h3>When to use <code class="directive"><Location></code></h3>
2609 <p>Use <code class="directive"><Location></code> to apply
2610 directives to content that lives outside the filesystem. For
2611 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
2612 <code><Location /></code>, which is an easy way to
2613 apply a configuration to the entire server.</p>
2616 <p>For all origin (non-proxy) requests, the URL to be matched is a
2617 URL-path of the form <code>/path/</code>. <em>No scheme, hostname,
2618 port, or query string may be included.</em> For proxy requests, the
2619 URL to be matched is of the form
2620 <code>scheme://servername/path</code>, and you must include the
2623 <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
2624 any single character, and <code>*</code> matches any sequences of
2625 characters. Neither wildcard character matches a / in the URL-path.</p>
2627 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
2628 can also be used, with the addition of the <code>~</code>
2629 character. For example:</p>
2631 <pre class="prettyprint lang-config"><Location ~ "/(extra|special)/data">
2633 </Location></pre>
2636 <p>would match URLs that contained the substring <code>/extra/data</code>
2637 or <code>/special/data</code>. The directive <code class="directive"><a href="#locationmatch"><LocationMatch></a></code> behaves
2638 identical to the regex version of <code class="directive"><Location></code>, and is preferred, for the
2639 simple reason that <code>~</code> is hard to distinguish from
2640 <code>-</code> in many fonts.</p>
2642 <p>The <code class="directive"><Location></code>
2643 functionality is especially useful when combined with the
2644 <code class="directive"><a href="#sethandler">SetHandler</a></code>
2645 directive. For example, to enable status requests, but allow them
2646 only from browsers at <code>example.com</code>, you might use:</p>
2648 <pre class="prettyprint lang-config"><Location /status>
2649 SetHandler server-status
2650 Require host example.com
2651 </Location></pre>
2654 <div class="note"><h3>Note about / (slash)</h3>
2655 <p>The slash character has special meaning depending on where in a
2656 URL it appears. People may be used to its behavior in the filesystem
2657 where multiple adjacent slashes are frequently collapsed to a single
2658 slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
2659 <code>/home/foo</code>). In URL-space this is not necessarily true.
2660 The <code class="directive"><a href="#locationmatch"><LocationMatch></a></code>
2661 directive and the regex version of <code class="directive"><Location></code> require you to explicitly specify multiple
2662 slashes if that is your intention.</p>
2664 <p>For example, <code><LocationMatch ^/abc></code> would match
2665 the request URL <code>/abc</code> but not the request URL <code>
2666 //abc</code>. The (non-regex) <code class="directive"><Location></code> directive behaves similarly when used for
2667 proxy requests. But when (non-regex) <code class="directive"><Location></code> is used for non-proxy requests it will
2668 implicitly match multiple slashes with a single slash. For example,
2669 if you specify <code><Location /abc/def></code> and the
2670 request is to <code>/abc//def</code> then it will match.</p>
2675 <li><a href="../sections.html">How <Directory>, <Location>
2676 and <Files> sections work</a> for an explanation of how these
2677 different sections are combined when a request is received.</li>
2678 <li><code class="directive"><a href="#locationmatch">LocationMatch</a></code></li>
2681 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2682 <div class="directive-section"><h2><a name="LocationMatch" id="LocationMatch"><LocationMatch></a> <a name="locationmatch" id="locationmatch">Directive</a></h2>
2683 <table class="directive">
2684 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to regular-expression
2685 matching URLs</td></tr>
2686 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LocationMatch
2687 <var>regex</var>> ... </LocationMatch></code></td></tr>
2688 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2689 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2690 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2692 <p>The <code class="directive"><LocationMatch></code> directive
2693 limits the scope of the enclosed directives by URL, in an identical manner
2694 to <code class="directive"><a href="#location"><Location></a></code>. However,
2695 it takes a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
2696 as an argument instead of a simple string. For example:</p>
2698 <pre class="prettyprint lang-config"><LocationMatch "/(extra|special)/data">
2700 </LocationMatch></pre>
2703 <p>would match URLs that contained the substring <code>/extra/data</code>
2704 or <code>/special/data</code>.</p>
2706 <p>From 2.4.8 onwards, named groups and backreferences are captured and
2707 written to the environment with the corresponding name prefixed with
2708 "MATCH_" and in upper case. This allows elements of URLs to be referenced
2709 from within <a href="../expr.html">expressions</a> and modules like
2710 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
2711 (unnamed) backreferences are ignored. Use named groups instead.</p>
2713 <pre class="prettyprint lang-config"><LocationMatch ^/combined/(?<sitename>[^/]+)>
2714 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
2715 </LocationMatch></pre>
2720 <li><a href="../sections.html">How <Directory>, <Location>
2721 and <Files> sections work</a> for an explanation of how these
2722 different sections are combined when a request is received</li>
2725 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2726 <div class="directive-section"><h2><a name="LogLevel" id="LogLevel">LogLevel</a> <a name="loglevel" id="loglevel">Directive</a></h2>
2727 <table class="directive">
2728 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Controls the verbosity of the ErrorLog</td></tr>
2729 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel [<var>module</var>:]<var>level</var>
2730 [<var>module</var>:<var>level</var>] ...
2732 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LogLevel warn</code></td></tr>
2733 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2734 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2735 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2736 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Per-module and per-directory configuration is available in
2737 Apache HTTP Server 2.3.6 and later</td></tr>
2739 <p><code class="directive">LogLevel</code> adjusts the verbosity of the
2740 messages recorded in the error logs (see <code class="directive"><a href="#errorlog">ErrorLog</a></code> directive). The following
2741 <var>level</var>s are available, in order of decreasing
2744 <table class="bordered">
2747 <th><strong>Level</strong> </th>
2749 <th><strong>Description</strong> </th>
2751 <th><strong>Example</strong> </th>
2755 <td><code>emerg</code> </td>
2757 <td>Emergencies - system is unusable.</td>
2759 <td>"Child cannot open lock file. Exiting"</td>
2763 <td><code>alert</code> </td>
2765 <td>Action must be taken immediately.</td>
2767 <td>"getpwuid: couldn't determine user name from uid"</td>
2771 <td><code>crit</code> </td>
2773 <td>Critical Conditions.</td>
2775 <td>"socket: Failed to get a socket, exiting child"</td>
2779 <td><code>error</code> </td>
2781 <td>Error conditions.</td>
2783 <td>"Premature end of script headers"</td>
2787 <td><code>warn</code> </td>
2789 <td>Warning conditions.</td>
2791 <td>"child process 1234 did not exit, sending another
2796 <td><code>notice</code> </td>
2798 <td>Normal but significant condition.</td>
2800 <td>"httpd: caught SIGBUS, attempting to dump core in
2805 <td><code>info</code> </td>
2807 <td>Informational.</td>
2809 <td>"Server seems busy, (you may need to increase
2810 StartServers, or Min/MaxSpareServers)..."</td>
2814 <td><code>debug</code> </td>
2816 <td>Debug-level messages</td>
2818 <td>"Opening config file ..."</td>
2821 <td><code>trace1</code> </td>
2823 <td>Trace messages</td>
2825 <td>"proxy: FTP: control connection complete"</td>
2828 <td><code>trace2</code> </td>
2830 <td>Trace messages</td>
2832 <td>"proxy: CONNECT: sending the CONNECT request to the remote proxy"</td>
2835 <td><code>trace3</code> </td>
2837 <td>Trace messages</td>
2839 <td>"openssl: Handshake: start"</td>
2842 <td><code>trace4</code> </td>
2844 <td>Trace messages</td>
2846 <td>"read from buffered SSL brigade, mode 0, 17 bytes"</td>
2849 <td><code>trace5</code> </td>
2851 <td>Trace messages</td>
2853 <td>"map lookup FAILED: map=rewritemap key=keyname"</td>
2856 <td><code>trace6</code> </td>
2858 <td>Trace messages</td>
2860 <td>"cache lookup FAILED, forcing new map lookup"</td>
2863 <td><code>trace7</code> </td>
2865 <td>Trace messages, dumping large amounts of data</td>
2867 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2870 <td><code>trace8</code> </td>
2872 <td>Trace messages, dumping large amounts of data</td>
2874 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2878 <p>When a particular level is specified, messages from all
2879 other levels of higher significance will be reported as well.
2880 <em>E.g.</em>, when <code>LogLevel info</code> is specified,
2881 then messages with log levels of <code>notice</code> and
2882 <code>warn</code> will also be posted.</p>
2884 <p>Using a level of at least <code>crit</code> is
2889 <pre class="prettyprint lang-config">LogLevel notice</pre>
2892 <div class="note"><h3>Note</h3>
2893 <p>When logging to a regular file messages of the level
2894 <code>notice</code> cannot be suppressed and thus are always
2895 logged. However, this doesn't apply when logging is done
2896 using <code>syslog</code>.</p>
2899 <p>Specifying a level without a module name will reset the level
2900 for all modules to that level. Specifying a level with a module
2901 name will set the level for that module only. It is possible to
2902 use the module source file name, the module identifier, or the
2903 module identifier with the trailing <code>_module</code> omitted
2904 as module specification. This means the following three specifications
2907 <pre class="prettyprint lang-config">LogLevel info ssl:warn
2908 LogLevel info mod_ssl.c:warn
2909 LogLevel info ssl_module:warn</pre>
2912 <p>It is also possible to change the level per directory:</p>
2914 <pre class="prettyprint lang-config">LogLevel info
2915 <Directory "/usr/local/apache/htdocs/app">
2917 </Directory></pre>
2921 Per directory loglevel configuration only affects messages that are
2922 logged after the request has been parsed and that are associated with
2923 the request. Log messages which are associated with the server or
2924 the connection are not affected. The latter can be influenced by the
2925 <code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code> directive,
2931 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
2932 <li><code class="directive"><a href="#errorlogformat">ErrorLogFormat</a></code></li>
2933 <li><code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code></li>
2934 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
2937 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2938 <div class="directive-section"><h2><a name="LogLevelOverride" id="LogLevelOverride">LogLevelOverride</a> <a name="logleveloverride" id="logleveloverride">Directive</a></h2>
2939 <table class="directive">
2940 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Override the verbosity of the ErrorLog for certain clients</td></tr>
2941 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel <var>ipaddress</var>[/<var>prefixlen</var>]
2942 [<var>module</var>:]<var>level</var> [<var>module</var>:<var>level</var>] ...
2944 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>unset</code></td></tr>
2945 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2946 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2947 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2948 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.5.0 and later</td></tr>
2950 <p><code class="directive">LogLevelOverride</code> adjusts the
2951 <code class="directive"><a href="#loglevel">LogLevel</a></code> for requests coming from
2952 certain client IP addresses.
2953 This allows to enable verbose logging only for certain test clients.
2954 The IP address is checked at a very early state in the connection
2955 processing. Therefore, <code class="directive">LogLevelOverride</code> allows to
2956 change the log level for things like the SSL handshake which happen before
2957 a <code class="directive"><a href="#loglevel">LogLevel</a></code> directive in an
2958 <code class="directive"><a href="#if"><If></a></code> container would
2961 <p><code class="directive">LogLevelOverride</code> accepts either a single
2962 IP-address or a CIDR IP-address/len subnet specification.
2963 For the syntax of the loglevel specification, see the
2964 <code class="directive"><a href="#loglevel">LogLevel</a></code> directive.</p>
2966 <p>For requests that match a <code class="directive">LogLevelOverride</code>
2967 directive, per-directory specifications of
2968 <code class="directive"><a href="#loglevel">LogLevel</a></code> are ignored.</p>
2972 <pre class="prettyprint lang-config"> LogLevelOverride 192.0.2.0/24 ssl:trace6
2973 LogLevelOverride 192.0.2.7 ssl:trace8</pre>
2977 <code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code> only affects
2978 log messages that are associated with the request or the connection.
2979 Log messages which are associated with the server not affected.
2985 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
2988 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2989 <div class="directive-section"><h2><a name="MaxKeepAliveRequests" id="MaxKeepAliveRequests">MaxKeepAliveRequests</a> <a name="maxkeepaliverequests" id="maxkeepaliverequests">Directive</a></h2>
2990 <table class="directive">
2991 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of requests allowed on a persistent
2992 connection</td></tr>
2993 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxKeepAliveRequests <var>number</var></code></td></tr>
2994 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxKeepAliveRequests 100</code></td></tr>
2995 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2996 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2997 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2999 <p>The <code class="directive">MaxKeepAliveRequests</code> directive
3000 limits the number of requests allowed per connection when
3001 <code class="directive"><a href="#keepalive">KeepAlive</a></code> is on. If it is
3002 set to <code>0</code>, unlimited requests will be allowed. We
3003 recommend that this setting be kept to a high value for maximum
3004 server performance.</p>
3008 <pre class="prettyprint lang-config">MaxKeepAliveRequests 500</pre>
3012 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3013 <div class="directive-section"><h2><a name="MaxRangeOverlaps" id="MaxRangeOverlaps">MaxRangeOverlaps</a> <a name="maxrangeoverlaps" id="maxrangeoverlaps">Directive</a></h2>
3014 <table class="directive">
3015 <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
3017 <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>
3018 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeOverlaps 20</code></td></tr>
3019 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3020 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3021 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3022 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3024 <p>The <code class="directive">MaxRangeOverlaps</code> directive
3025 limits the number of overlapping HTTP ranges the server is willing to
3026 return to the client. If more overlapping ranges than permitted are requested,
3027 the complete resource is returned instead.</p>
3030 <dt><strong>default</strong></dt>
3031 <dd>Limits the number of overlapping ranges to a compile-time default of 20.</dd>
3033 <dt><strong>none</strong></dt>
3034 <dd>No overlapping Range headers are allowed.</dd>
3036 <dt><strong>unlimited</strong></dt>
3037 <dd>The server does not limit the number of overlapping ranges it is
3038 willing to satisfy.</dd>
3040 <dt><var>number-of-ranges</var></dt>
3041 <dd>A positive number representing the maximum number of overlapping ranges the
3042 server is willing to satisfy.</dd>
3046 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3047 <div class="directive-section"><h2><a name="MaxRangeReversals" id="MaxRangeReversals">MaxRangeReversals</a> <a name="maxrangereversals" id="maxrangereversals">Directive</a></h2>
3048 <table class="directive">
3049 <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
3051 <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>
3052 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeReversals 20</code></td></tr>
3053 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3054 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3055 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3056 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3058 <p>The <code class="directive">MaxRangeReversals</code> directive
3059 limits the number of HTTP Range reversals the server is willing to
3060 return to the client. If more ranges reversals than permitted are requested,
3061 the complete resource is returned instead.</p>
3064 <dt><strong>default</strong></dt>
3065 <dd>Limits the number of range reversals to a compile-time default of 20.</dd>
3067 <dt><strong>none</strong></dt>
3068 <dd>No Range reversals headers are allowed.</dd>
3070 <dt><strong>unlimited</strong></dt>
3071 <dd>The server does not limit the number of range reversals it is
3072 willing to satisfy.</dd>
3074 <dt><var>number-of-ranges</var></dt>
3075 <dd>A positive number representing the maximum number of range reversals the
3076 server is willing to satisfy.</dd>
3080 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3081 <div class="directive-section"><h2><a name="MaxRanges" id="MaxRanges">MaxRanges</a> <a name="maxranges" id="maxranges">Directive</a></h2>
3082 <table class="directive">
3083 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of ranges allowed before returning the complete
3085 <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>
3086 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRanges 200</code></td></tr>
3087 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3088 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3089 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3090 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3092 <p>The <code class="directive">MaxRanges</code> directive
3093 limits the number of HTTP ranges the server is willing to
3094 return to the client. If more ranges than permitted are requested,
3095 the complete resource is returned instead.</p>
3098 <dt><strong>default</strong></dt>
3099 <dd>Limits the number of ranges to a compile-time default of 200.</dd>
3101 <dt><strong>none</strong></dt>
3102 <dd>Range headers are ignored.</dd>
3104 <dt><strong>unlimited</strong></dt>
3105 <dd>The server does not limit the number of ranges it is
3106 willing to satisfy.</dd>
3108 <dt><var>number-of-ranges</var></dt>
3109 <dd>A positive number representing the maximum number of ranges the
3110 server is willing to satisfy.</dd>
3114 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3115 <div class="directive-section"><h2><a name="Mutex" id="Mutex">Mutex</a> <a name="mutex" id="mutex">Directive</a></h2>
3116 <table class="directive">
3117 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures mutex mechanism and lock file directory for all
3118 or specified mutexes</td></tr>
3119 <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>
3120 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Mutex default</code></td></tr>
3121 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3122 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3123 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3124 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.4 and later</td></tr>
3126 <p>The <code class="directive">Mutex</code> directive sets the mechanism,
3127 and optionally the lock file location, that httpd and modules use
3128 to serialize access to resources. Specify <code>default</code> as
3129 the first argument to change the settings for all mutexes; specify
3130 a mutex name (see table below) as the first argument to override
3131 defaults only for that mutex.</p>
3133 <p>The <code class="directive">Mutex</code> directive is typically used in
3134 the following exceptional situations:</p>
3137 <li>change the mutex mechanism when the default mechanism selected
3138 by <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> has a functional or performance
3141 <li>change the directory used by file-based mutexes when the
3142 default directory does not support locking</li>
3145 <div class="note"><h3>Supported modules</h3>
3146 <p>This directive only configures mutexes which have been registered
3147 with the core server using the <code>ap_mutex_register()</code> API.
3148 All modules bundled with httpd support the <code class="directive">Mutex</code>
3149 directive, but third-party modules may not. Consult the documentation
3150 of the third-party module, which must indicate the mutex name(s) which
3151 can be configured if this directive is supported.</p>
3154 <p>The following mutex <em>mechanisms</em> are available:</p>
3156 <li><code>default | yes</code>
3157 <p>This selects the default locking implementation, as determined by
3158 <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a>. The default locking implementation can
3159 be displayed by running <code class="program"><a href="../programs/httpd.html">httpd</a></code> with the
3160 <code>-V</code> option.</p></li>
3162 <li><code>none | no</code>
3163 <p>This effectively disables the mutex, and is only allowed for a
3164 mutex if the module indicates that it is a valid choice. Consult the
3165 module documentation for more information.</p></li>
3167 <li><code>posixsem</code>
3168 <p>This is a mutex variant based on a Posix semaphore.</p>
3170 <div class="warning"><h3>Warning</h3>
3171 <p>The semaphore ownership is not recovered if a thread in the process
3172 holding the mutex segfaults, resulting in a hang of the web server.</p>
3176 <li><code>sysvsem</code>
3177 <p>This is a mutex variant based on a SystemV IPC semaphore.</p>
3179 <div class="warning"><h3>Warning</h3>
3180 <p>It is possible to "leak" SysV semaphores if processes crash
3181 before the semaphore is removed.</p>
3184 <div class="warning"><h3>Security</h3>
3185 <p>The semaphore API allows for a denial of service attack by any
3186 CGIs running under the same uid as the webserver (<em>i.e.</em>,
3187 all CGIs, unless you use something like <code class="program"><a href="../programs/suexec.html">suexec</a></code>
3188 or <code>cgiwrapper</code>).</p>
3192 <li><code>sem</code>
3193 <p>This selects the "best" available semaphore implementation, choosing
3194 between Posix and SystemV IPC semaphores, in that order.</p></li>
3196 <li><code>pthread</code>
3197 <p>This is a mutex variant based on cross-process Posix thread
3200 <div class="warning"><h3>Warning</h3>
3201 <p>On most systems, if a child process terminates abnormally while
3202 holding a mutex that uses this implementation, the server will deadlock
3203 and stop responding to requests. When this occurs, the server will
3204 require a manual restart to recover.</p>
3205 <p>Solaris is a notable exception as it provides a mechanism which
3206 usually allows the mutex to be recovered after a child process
3207 terminates abnormally while holding a mutex.</p>
3208 <p>If your system implements the
3209 <code>pthread_mutexattr_setrobust_np()</code> function, you may be able
3210 to use the <code>pthread</code> option safely.</p>
3214 <li><code>fcntl:/path/to/mutex</code>
3215 <p>This is a mutex variant where a physical (lock-)file and the
3216 <code>fcntl()</code> function are used as the mutex.</p>
3218 <div class="warning"><h3>Warning</h3>
3219 <p>When multiple mutexes based on this mechanism are used within
3220 multi-threaded, multi-process environments, deadlock errors (EDEADLK)
3221 can be reported for valid mutex operations if <code>fcntl()</code>
3222 is not thread-aware, such as on Solaris.</p>
3226 <li><code>flock:/path/to/mutex</code>
3227 <p>This is similar to the <code>fcntl:/path/to/mutex</code> method
3228 with the exception that the <code>flock()</code> function is used to
3229 provide file locking.</p></li>
3231 <li><code>file:/path/to/mutex</code>
3232 <p>This selects the "best" available file locking implementation,
3233 choosing between <code>fcntl</code> and <code>flock</code>, in that
3237 <p>Most mechanisms are only available on selected platforms, where the
3238 underlying platform and <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> support it. Mechanisms
3239 which aren't available on all platforms are <em>posixsem</em>,
3240 <em>sysvsem</em>, <em>sem</em>, <em>pthread</em>, <em>fcntl</em>,
3241 <em>flock</em>, and <em>file</em>.</p>
3243 <p>With the file-based mechanisms <em>fcntl</em> and <em>flock</em>,
3244 the path, if provided, is a directory where the lock file will be created.
3245 The default directory is httpd's run-time file directory,
3246 <code class="directive"><a href="#defaultruntimedir">DefaultRuntimeDir</a></code>. If a relative
3247 path is provided, it is relative to
3248 <code class="directive"><a href="#defaultruntimedir">DefaultRuntimeDir</a></code>. Always use a local
3249 disk filesystem for <code>/path/to/mutex</code> and never a directory residing
3250 on a NFS- or AFS-filesystem. The basename of the file will be the mutex
3251 type, an optional instance string provided by the module, and unless the
3252 <code>OmitPID</code> keyword is specified, the process id of the httpd
3253 parent process will be appended to to make the file name unique, avoiding
3254 conflicts when multiple httpd instances share a lock file directory. For
3255 example, if the mutex name is <code>mpm-accept</code> and the lock file
3256 directory is <code>/var/httpd/locks</code>, the lock file name for the
3257 httpd instance with parent process id 12345 would be
3258 <code>/var/httpd/locks/mpm-accept.12345</code>.</p>
3260 <div class="warning"><h3>Security</h3>
3261 <p>It is best to <em>avoid</em> putting mutex files in a world-writable
3262 directory such as <code>/var/tmp</code> because someone could create
3263 a denial of service attack and prevent the server from starting by
3264 creating a lockfile with the same name as the one the server will try
3268 <p>The following table documents the names of mutexes used by httpd
3269 and bundled modules.</p>
3271 <table class="bordered"><tr class="header">
3274 <th>Protected resource</th>
3277 <td><code>mpm-accept</code></td>
3278 <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>
3279 <td>incoming connections, to avoid the thundering herd problem;
3280 for more information, refer to the
3281 <a href="../misc/perf-tuning.html">performance tuning</a>
3285 <td><code>authdigest-client</code></td>
3286 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3287 <td>client list in shared memory</td>
3290 <td><code>authdigest-opaque</code></td>
3291 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3292 <td>counter in shared memory</td>
3295 <td><code>ldap-cache</code></td>
3296 <td><code class="module"><a href="../mod/mod_ldap.html">mod_ldap</a></code></td>
3297 <td>LDAP result cache</td>
3300 <td><code>rewrite-map</code></td>
3301 <td><code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code></td>
3302 <td>communication with external mapping programs, to avoid
3303 intermixed I/O from multiple requests</td>
3306 <td><code>ssl-cache</code></td>
3307 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3308 <td>SSL session cache</td>
3311 <td><code>ssl-stapling</code></td>
3312 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3313 <td>OCSP stapling response cache</td>
3316 <td><code>watchdog-callback</code></td>
3317 <td><code class="module"><a href="../mod/mod_watchdog.html">mod_watchdog</a></code></td>
3318 <td>callback function of a particular client module</td>
3322 <p>The <code>OmitPID</code> keyword suppresses the addition of the httpd
3323 parent process id from the lock file name.</p>
3325 <p>In the following example, the mutex mechanism for the MPM accept
3326 mutex will be changed from the compiled-in default to <code>fcntl</code>,
3327 with the associated lock file created in directory
3328 <code>/var/httpd/locks</code>. The mutex mechanism for all other mutexes
3329 will be changed from the compiled-in default to <code>sysvsem</code>.</p>
3331 <pre class="prettyprint lang-config">Mutex sysvsem default
3332 Mutex fcntl:/var/httpd/locks mpm-accept</pre>
3336 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3337 <div class="directive-section"><h2><a name="NameVirtualHost" id="NameVirtualHost">NameVirtualHost</a> <a name="namevirtualhost" id="namevirtualhost">Directive</a></h2>
3338 <table class="directive">
3339 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>DEPRECATED: Designates an IP address for name-virtual
3341 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NameVirtualHost <var>addr</var>[:<var>port</var>]</code></td></tr>
3342 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3343 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3344 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3347 <p>Prior to 2.3.11, <code class="directive">NameVirtualHost</code> was required
3348 to instruct the server that a particular IP address and port combination
3349 was usable as a name-based virtual host. In 2.3.11 and later,
3350 any time an IP address and port combination is used in multiple virtual
3351 hosts, name-based virtual hosting is automatically enabled for that address.</p>
3353 <p>This directive currently has no effect.</p>
3357 <li><a href="../vhosts/">Virtual Hosts
3358 documentation</a></li>
3361 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3362 <div class="directive-section"><h2><a name="Options" id="Options">Options</a> <a name="options" id="options">Directive</a></h2>
3363 <table class="directive">
3364 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures what features are available in a particular
3366 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Options
3367 [+|-]<var>option</var> [[+|-]<var>option</var>] ...</code></td></tr>
3368 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Options FollowSymlinks</code></td></tr>
3369 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3370 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
3371 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3372 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3373 <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>
3375 <p>The <code class="directive">Options</code> directive controls which
3376 server features are available in a particular directory.</p>
3378 <p><var>option</var> can be set to <code>None</code>, in which
3379 case none of the extra features are enabled, or one or more of
3383 <dt><code>All</code></dt>
3385 <dd>All options except for <code>MultiViews</code>.</dd>
3387 <dt><code>ExecCGI</code></dt>
3390 Execution of CGI scripts using <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>
3393 <dt><code>FollowSymLinks</code></dt>
3396 The server will follow symbolic links in this directory. This is
3397 the default setting.
3399 <p>Even though the server follows the symlink it does <em>not</em>
3400 change the pathname used to match against <code class="directive"><a href="#directory"><Directory></a></code> sections.</p>
3402 <p>The <code>FollowSymLinks</code> and
3403 <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
3404 <code>.htaccess</code> files.</p>
3406 <p>Omitting this option should not be considered a security restriction,
3407 since symlink testing is subject to race conditions that make it
3411 <dt><code>Includes</code></dt>
3414 Server-side includes provided by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
3417 <dt><code>IncludesNOEXEC</code></dt>
3421 Server-side includes are permitted, but the <code>#exec
3422 cmd</code> and <code>#exec cgi</code> are disabled. It is still
3423 possible to <code>#include virtual</code> CGI scripts from
3424 <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>ed
3427 <dt><code>Indexes</code></dt>
3430 If a URL which maps to a directory is requested, and there
3431 is no <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
3432 (<em>e.g.</em>, <code>index.html</code>) in that directory, then
3433 <code class="module"><a href="../mod/mod_autoindex.html">mod_autoindex</a></code> will return a formatted listing
3434 of the directory.</dd>
3436 <dt><code>MultiViews</code></dt>
3439 <a href="../content-negotiation.html">Content negotiated</a>
3440 "MultiViews" are allowed using
3441 <code class="module"><a href="../mod/mod_negotiation.html">mod_negotiation</a></code>.
3442 <div class="note"><h3>Note</h3> <p>This option gets ignored if set
3443 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>
3444 needs real resources to compare against and evaluate from.</p></div>
3447 <dt><code>SymLinksIfOwnerMatch</code></dt>
3449 <dd>The server will only follow symbolic links for which the
3450 target file or directory is owned by the same user id as the
3453 <div class="note"><h3>Note</h3>
3454 <p>The <code>FollowSymLinks</code> and
3455 <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
3456 <code>.htaccess</code> files.</p>
3458 <p>This option should not be considered a security restriction,
3459 since symlink testing is subject to race conditions that make it
3464 <p>Normally, if multiple <code class="directive">Options</code> could
3465 apply to a directory, then the most specific one is used and
3466 others are ignored; the options are not merged. (See <a href="../sections.html#mergin">how sections are merged</a>.)
3467 However if <em>all</em> the options on the
3468 <code class="directive">Options</code> directive are preceded by a
3469 <code>+</code> or <code>-</code> symbol, the options are
3470 merged. Any options preceded by a <code>+</code> are added to the
3471 options currently in force, and any options preceded by a
3472 <code>-</code> are removed from the options currently in
3475 <div class="note"><h3>Note</h3>
3476 <p>Mixing <code class="directive">Options</code> with a <code>+</code> or
3477 <code>-</code> with those without is not valid syntax, and will be
3478 rejected during server startup by the syntax check with an abort.</p>
3481 <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>
3483 <pre class="prettyprint lang-config"><Directory "/web/docs">
3484 Options Indexes FollowSymLinks
3487 <Directory "/web/docs/spec">
3489 </Directory></pre>
3492 <p>then only <code>Includes</code> will be set for the
3493 <code>/web/docs/spec</code> directory. However if the second
3494 <code class="directive">Options</code> directive uses the <code>+</code> and
3495 <code>-</code> symbols:</p>
3497 <pre class="prettyprint lang-config"><Directory "/web/docs">
3498 Options Indexes FollowSymLinks
3501 <Directory "/web/docs/spec">
3502 Options +Includes -Indexes
3503 </Directory></pre>
3506 <p>then the options <code>FollowSymLinks</code> and
3507 <code>Includes</code> are set for the <code>/web/docs/spec</code>
3510 <div class="note"><h3>Note</h3>
3511 <p>Using <code>-IncludesNOEXEC</code> or
3512 <code>-Includes</code> disables server-side includes completely
3513 regardless of the previous setting.</p>
3516 <p>The default in the absence of any other settings is
3517 <code>FollowSymlinks</code>.</p>
3520 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3521 <div class="directive-section"><h2><a name="Protocol" id="Protocol">Protocol</a> <a name="protocol" id="protocol">Directive</a></h2>
3522 <table class="directive">
3523 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Protocol for a listening socket</td></tr>
3524 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Protocol <var>protocol</var></code></td></tr>
3525 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3526 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3527 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3528 <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>
3530 <p>This directive specifies the protocol used for a specific listening socket.
3531 The protocol is used to determine which module should handle a request, and
3532 to apply protocol specific optimizations with the <code class="directive">AcceptFilter</code>
3535 <p>You only need to set the protocol if you are running on non-standard ports, otherwise <code>http</code> is assumed for port 80 and <code>https</code> for port 443.</p>
3537 <p>For example, if you are running <code>https</code> on a non-standard port, specify the protocol explicitly:</p>
3539 <pre class="prettyprint lang-config">Protocol https</pre>
3542 <p>You can also specify the protocol using the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code> directive.</p>
3546 <li><code class="directive"><a href="#acceptfilter">AcceptFilter</a></code></li>
3547 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
3550 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3551 <div class="directive-section"><h2><a name="RegisterHttpMethod" id="RegisterHttpMethod">RegisterHttpMethod</a> <a name="registerhttpmethod" id="registerhttpmethod">Directive</a></h2>
3552 <table class="directive">
3553 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Register non-standard HTTP methods</td></tr>
3554 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>RegisterHttpMethod <var>method</var> [<var>method</var> [...]]</code></td></tr>
3555 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3556 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3557 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3559 <p>HTTP Methods that are not conforming to the relvant RFCs are normally
3560 rejected by request processing in Apache HTTPD. To avoid this, modules
3561 can register non-standard HTTP methods they support.
3562 The <code class="directive">RegisterHttpMethod</code> allows to register such
3563 methods manually. This can be useful for if such methods are forwared
3564 for external processing, e.g. to a CGI script.</p>
3567 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3568 <div class="directive-section"><h2><a name="RLimitCPU" id="RLimitCPU">RLimitCPU</a> <a name="rlimitcpu" id="rlimitcpu">Directive</a></h2>
3569 <table class="directive">
3570 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the CPU consumption of processes launched
3571 by Apache httpd children</td></tr>
3572 <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>
3573 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3574 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3575 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3576 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3577 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3579 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3580 resource limit for all processes and the second parameter sets
3581 the maximum resource limit. Either parameter can be a number,
3582 or <code>max</code> to indicate to the server that the limit should
3583 be set to the maximum allowed by the operating system
3584 configuration. Raising the maximum resource limit requires that
3585 the server is running as <code>root</code>, or in the initial startup
3588 <p>This applies to processes forked off from Apache httpd children
3589 servicing requests, not the Apache httpd children themselves. This
3590 includes CGI scripts and SSI exec commands, but not any
3591 processes forked off from the Apache httpd parent such as piped
3594 <p>CPU resource limits are expressed in seconds per
3599 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3600 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3603 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3604 <div class="directive-section"><h2><a name="RLimitMEM" id="RLimitMEM">RLimitMEM</a> <a name="rlimitmem" id="rlimitmem">Directive</a></h2>
3605 <table class="directive">
3606 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the memory consumption of processes launched
3607 by Apache httpd children</td></tr>
3608 <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>
3609 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3610 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3611 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3612 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3613 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3615 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3616 resource limit for all processes and the second parameter sets
3617 the maximum resource limit. Either parameter can be a number,
3618 or <code>max</code> to indicate to the server that the limit should
3619 be set to the maximum allowed by the operating system
3620 configuration. Raising the maximum resource limit requires that
3621 the server is running as <code>root</code>, or in the initial startup
3624 <p>This applies to processes forked off from Apache httpd children
3625 servicing requests, not the Apache httpd children themselves. This
3626 includes CGI scripts and SSI exec commands, but not any
3627 processes forked off from the Apache httpd parent such as piped
3630 <p>Memory resource limits are expressed in bytes per
3635 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3636 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3639 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3640 <div class="directive-section"><h2><a name="RLimitNPROC" id="RLimitNPROC">RLimitNPROC</a> <a name="rlimitnproc" id="rlimitnproc">Directive</a></h2>
3641 <table class="directive">
3642 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of processes that can be launched by
3643 processes launched by Apache httpd children</td></tr>
3644 <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>
3645 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3646 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3647 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3648 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3649 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3651 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3652 resource limit for all processes and the second parameter sets
3653 the maximum resource limit. Either parameter can be a number,
3654 or <code>max</code> to indicate to the server that the limit
3655 should be set to the maximum allowed by the operating system
3656 configuration. Raising the maximum resource limit requires that
3657 the server is running as <code>root</code>, or in the initial startup
3660 <p>This applies to processes forked off from Apache httpd children
3661 servicing requests, not the Apache httpd children themselves. This
3662 includes CGI scripts and SSI exec commands, but not any
3663 processes forked off from the Apache httpd parent such as piped
3666 <p>Process limits control the number of processes per user.</p>
3668 <div class="note"><h3>Note</h3>
3669 <p>If CGI processes are <strong>not</strong> running
3670 under user ids other than the web server user id, this directive
3671 will limit the number of processes that the server itself can
3672 create. Evidence of this situation will be indicated by
3673 <strong><code>cannot fork</code></strong> messages in the
3674 <code>error_log</code>.</p>
3679 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3680 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3683 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3684 <div class="directive-section"><h2><a name="ScriptInterpreterSource" id="ScriptInterpreterSource">ScriptInterpreterSource</a> <a name="scriptinterpretersource" id="scriptinterpretersource">Directive</a></h2>
3685 <table class="directive">
3686 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
3688 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ScriptInterpreterSource Registry|Registry-Strict|Script</code></td></tr>
3689 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ScriptInterpreterSource Script</code></td></tr>
3690 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3691 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3692 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3693 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3694 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Win32 only.</td></tr>
3696 <p>This directive is used to control how Apache httpd finds the
3697 interpreter used to run CGI scripts. The default setting is
3698 <code>Script</code>. This causes Apache httpd to use the interpreter pointed to
3699 by the shebang line (first line, starting with <code>#!</code>) in the
3700 script. On Win32 systems this line usually looks like:</p>
3702 <pre class="prettyprint lang-perl">#!C:/Perl/bin/perl.exe</pre>
3705 <p>or, if <code>perl</code> is in the <code>PATH</code>, simply:</p>
3707 <pre class="prettyprint lang-perl">#!perl</pre>
3710 <p>Setting <code>ScriptInterpreterSource Registry</code> will
3711 cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
3712 searched using the script file extension (e.g., <code>.pl</code>) as a
3713 search key. The command defined by the registry subkey
3714 <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
3715 <code>Shell\Open\Command</code> is used to open the script file. If the
3716 registry keys cannot be found, Apache httpd falls back to the behavior of the
3717 <code>Script</code> option.</p>
3719 <div class="warning"><h3>Security</h3>
3720 <p>Be careful when using <code>ScriptInterpreterSource
3721 Registry</code> with <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>'ed directories, because
3722 Apache httpd will try to execute <strong>every</strong> file within this
3723 directory. The <code>Registry</code> setting may cause undesired
3724 program calls on files which are typically not executed. For
3725 example, the default open command on <code>.htm</code> files on
3726 most Windows systems will execute Microsoft Internet Explorer, so
3727 any HTTP request for an <code>.htm</code> file existing within the
3728 script directory would start the browser in the background on the
3729 server. This is a good way to crash your system within a minute or
3733 <p>The option <code>Registry-Strict</code> which is new in Apache HTTP Server
3734 2.0 does the same thing as <code>Registry</code> but uses only the
3735 subkey <code>Shell\ExecCGI\Command</code>. The
3736 <code>ExecCGI</code> key is not a common one. It must be
3737 configured manually in the windows registry and hence prevents
3738 accidental program calls on your system.</p>
3741 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3742 <div class="directive-section"><h2><a name="SeeRequestTail" id="SeeRequestTail">SeeRequestTail</a> <a name="seerequesttail" id="seerequesttail">Directive</a></h2>
3743 <table class="directive">
3744 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine if mod_status displays the first 63 characters
3745 of a request or the last 63, assuming the request itself is greater than
3747 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SeeRequestTail On|Off</code></td></tr>
3748 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SeeRequestTail Off</code></td></tr>
3749 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3750 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3751 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3753 <p>mod_status with <code>ExtendedStatus On</code>
3754 displays the actual request being handled.
3755 For historical purposes, only 63 characters of the request
3756 are actually stored for display purposes. This directive
3757 controls whether the 1st 63 characters are stored (the previous
3758 behavior and the default) or if the last 63 characters are. This
3759 is only applicable, of course, if the length of the request is
3760 64 characters or greater.</p>
3762 <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:
3765 <table class="bordered">
3767 <th>Off (default)</th>
3768 <td>GET /disk1/storage/apache/htdocs/images/imagestore1/food/apples</td>
3772 <td>orage/apache/htdocs/images/imagestore1/food/apples.jpg HTTP/1.1</td>
3778 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3779 <div class="directive-section"><h2><a name="ServerAdmin" id="ServerAdmin">ServerAdmin</a> <a name="serveradmin" id="serveradmin">Directive</a></h2>
3780 <table class="directive">
3781 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Email address that the server includes in error
3782 messages sent to the client</td></tr>
3783 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAdmin <var>email-address</var>|<var>URL</var></code></td></tr>
3784 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3785 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3786 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3788 <p>The <code class="directive">ServerAdmin</code> sets the contact address
3789 that the server includes in any error messages it returns to the
3790 client. If the <code>httpd</code> doesn't recognize the supplied argument
3792 assumes, that it's an <var>email-address</var> and prepends it with
3793 <code>mailto:</code> in hyperlink targets. However, it's recommended to
3794 actually use an email address, since there are a lot of CGI scripts that
3795 make that assumption. If you want to use an URL, it should point to another
3796 server under your control. Otherwise users may not be able to contact you in
3799 <p>It may be worth setting up a dedicated address for this, e.g.</p>
3801 <pre class="prettyprint lang-config">ServerAdmin www-admin@foo.example.com</pre>
3803 <p>as users do not always mention that they are talking about the
3807 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3808 <div class="directive-section"><h2><a name="ServerAlias" id="ServerAlias">ServerAlias</a> <a name="serveralias" id="serveralias">Directive</a></h2>
3809 <table class="directive">
3810 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Alternate names for a host used when matching requests
3811 to name-virtual hosts</td></tr>
3812 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</code></td></tr>
3813 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
3814 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3815 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3817 <p>The <code class="directive">ServerAlias</code> directive sets the
3818 alternate names for a host, for use with <a href="../vhosts/name-based.html">name-based virtual hosts</a>. The
3819 <code class="directive">ServerAlias</code> may include wildcards, if appropriate.</p>
3821 <pre class="prettyprint lang-config"><VirtualHost *:80>
3822 ServerName server.example.com
3823 ServerAlias server server2.example.com server2
3824 ServerAlias *.example.com
3825 UseCanonicalName Off
3827 </VirtualHost></pre>
3830 <p>Name-based virtual hosts for the best-matching set of <code class="directive"><a href="#virtualhost"><virtualhost></a></code>s are processed
3831 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
3832 (nor for ServerName vs. ServerAlias). </p>
3834 <p>The complete list of names in the <code class="directive">VirtualHost</code>
3835 directive are treated just like a (non wildcard)
3836 <code class="directive">ServerAlias</code>.</p>
3841 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3842 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
3845 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3846 <div class="directive-section"><h2><a name="ServerName" id="ServerName">ServerName</a> <a name="servername" id="servername">Directive</a></h2>
3847 <table class="directive">
3848 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hostname and port that the server uses to identify
3850 <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>
3851 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3852 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3853 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3855 <p>The <code class="directive">ServerName</code> directive sets the
3856 request scheme, hostname and
3857 port that the server uses to identify itself. This is used when
3858 creating redirection URLs.</p>
3860 <p>Additionally, <code class="directive">ServerName</code> is used (possibly
3861 in conjunction with <code class="directive">ServerAlias</code>) to uniquely
3862 identify a virtual host, when using <a href="../vhosts/name-based.html">name-based virtual hosts</a>.</p>
3864 <p>For example, if the name of the
3865 machine hosting the web server is <code>simple.example.com</code>,
3866 but the machine also has the DNS alias <code>www.example.com</code>
3867 and you wish the web server to be so identified, the following
3868 directive should be used:</p>
3870 <pre class="prettyprint lang-config">ServerName www.example.com</pre>
3873 <p>The <code class="directive">ServerName</code> directive
3874 may appear anywhere within the definition of a server. However,
3875 each appearance overrides the previous appearance (within that
3878 <p>If no <code class="directive">ServerName</code> is specified, then the
3879 server attempts to deduce the hostname by performing a reverse
3880 lookup on the IP address. If no port is specified in the
3881 <code class="directive">ServerName</code>, then the server will use the
3882 port from the incoming request. For optimal reliability and
3883 predictability, you should specify an explicit hostname and port
3884 using the <code class="directive">ServerName</code> directive.</p>
3886 <p>If you are using <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
3887 the <code class="directive">ServerName</code> inside a
3888 <code class="directive"><a href="#virtualhost"><VirtualHost></a></code>
3889 section specifies what hostname must appear in the request's
3890 <code>Host:</code> header to match this virtual host.</p>
3892 <p>Sometimes, the server runs behind a device that processes SSL,
3893 such as a reverse proxy, load balancer or SSL offload
3894 appliance. When this is the case, specify the
3895 <code>https://</code> scheme and the port number to which the
3896 clients connect in the <code class="directive">ServerName</code> directive
3897 to make sure that the server generates the correct
3898 self-referential URLs.
3901 <p>See the description of the
3902 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> and
3903 <code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code> directives for
3904 settings which determine whether self-referential URLs (e.g., by the
3905 <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> module) will refer to the
3906 specified port, or to the port number given in the client's request.
3909 <div class="warning">
3910 <p>Failure to set <code class="directive">ServerName</code> to a name that
3911 your server can resolve to an IP address will result in a startup
3912 warning. <code>httpd</code> will then use whatever hostname it can
3913 determine, using the system's <code>hostname</code> command. This
3914 will almost never be the hostname you actually want.</p>
3915 <div class="example"><p><code>
3916 httpd: Could not reliably determine the server's fully qualified domain name, using rocinante.local for ServerName
3923 <li><a href="../dns-caveats.html">Issues Regarding DNS and
3924 Apache HTTP Server</a></li>
3925 <li><a href="../vhosts/">Apache HTTP Server virtual host
3926 documentation</a></li>
3927 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3928 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
3929 <li><code class="directive"><a href="#serveralias">ServerAlias</a></code></li>
3932 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3933 <div class="directive-section"><h2><a name="ServerPath" id="ServerPath">ServerPath</a> <a name="serverpath" id="serverpath">Directive</a></h2>
3934 <table class="directive">
3935 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Legacy URL pathname for a name-based virtual host that
3936 is accessed by an incompatible browser</td></tr>
3937 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerPath <var>URL-path</var></code></td></tr>
3938 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
3939 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3940 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3942 <p>The <code class="directive">ServerPath</code> directive sets the legacy
3943 URL pathname for a host, for use with <a href="../vhosts/">name-based virtual hosts</a>.</p>
3947 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
3950 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3951 <div class="directive-section"><h2><a name="ServerRoot" id="ServerRoot">ServerRoot</a> <a name="serverroot" id="serverroot">Directive</a></h2>
3952 <table class="directive">
3953 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server installation</td></tr>
3954 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerRoot <var>directory-path</var></code></td></tr>
3955 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerRoot /usr/local/apache</code></td></tr>
3956 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3957 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3958 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3960 <p>The <code class="directive">ServerRoot</code> directive sets the
3961 directory in which the server lives. Typically it will contain the
3962 subdirectories <code>conf/</code> and <code>logs/</code>. Relative
3963 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
3964 relative to this directory.</p>
3966 <pre class="prettyprint lang-config">ServerRoot "/home/httpd"</pre>
3969 <p>The default location of <code class="directive">ServerRoot</code> may be
3970 modified by using the <code>--prefix</code> argument to
3971 <a href="../programs/configure.html"><code>configure</code></a>, and
3972 most third-party distributions of the server have a different
3973 default location from the one listed above.</p>
3978 <li><a href="../invoking.html">the <code>-d</code>
3979 option to <code>httpd</code></a></li>
3980 <li><a href="../misc/security_tips.html#serverroot">the
3981 security tips</a> for information on how to properly set
3982 permissions on the <code class="directive">ServerRoot</code></li>
3985 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3986 <div class="directive-section"><h2><a name="ServerSignature" id="ServerSignature">ServerSignature</a> <a name="serversignature" id="serversignature">Directive</a></h2>
3987 <table class="directive">
3988 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the footer on server-generated documents</td></tr>
3989 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerSignature On|Off|EMail</code></td></tr>
3990 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerSignature Off</code></td></tr>
3991 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3992 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3993 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3994 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3996 <p>The <code class="directive">ServerSignature</code> directive allows the
3997 configuration of a trailing footer line under server-generated
3998 documents (error messages, <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> ftp directory
3999 listings, <code class="module"><a href="../mod/mod_info.html">mod_info</a></code> output, ...). The reason why you
4000 would want to enable such a footer line is that in a chain of proxies,
4001 the user often has no possibility to tell which of the chained servers
4002 actually produced a returned error message.</p>
4004 <p>The <code>Off</code>
4005 setting, which is the default, suppresses the footer line (and is
4006 therefore compatible with the behavior of Apache-1.2 and
4007 below). The <code>On</code> setting simply adds a line with the
4008 server version number and <code class="directive"><a href="#servername">ServerName</a></code> of the serving virtual host,
4009 and the <code>EMail</code> setting additionally creates a
4010 "mailto:" reference to the <code class="directive"><a href="#serveradmin">ServerAdmin</a></code> of the referenced
4013 <p>After version 2.0.44, the details of the server version number
4014 presented are controlled by the <code class="directive"><a href="#servertokens">ServerTokens</a></code> directive.</p>
4018 <li><code class="directive"><a href="#servertokens">ServerTokens</a></code></li>
4021 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4022 <div class="directive-section"><h2><a name="ServerTokens" id="ServerTokens">ServerTokens</a> <a name="servertokens" id="servertokens">Directive</a></h2>
4023 <table class="directive">
4024 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the <code>Server</code> HTTP response
4026 <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>
4027 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerTokens Full</code></td></tr>
4028 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4029 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4030 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4032 <p>This directive controls whether <code>Server</code> response
4033 header field which is sent back to clients includes a
4034 description of the generic OS-type of the server as well as
4035 information about compiled-in modules.</p>
4038 <dt><code>ServerTokens Full</code> (or not specified)</dt>
4040 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4041 (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
4043 <dt><code>ServerTokens Prod[uctOnly]</code></dt>
4045 <dd>Server sends (<em>e.g.</em>): <code>Server:
4048 <dt><code>ServerTokens Major</code></dt>
4050 <dd>Server sends (<em>e.g.</em>): <code>Server:
4051 Apache/2</code></dd>
4053 <dt><code>ServerTokens Minor</code></dt>
4055 <dd>Server sends (<em>e.g.</em>): <code>Server:
4056 Apache/2.4</code></dd>
4058 <dt><code>ServerTokens Min[imal]</code></dt>
4060 <dd>Server sends (<em>e.g.</em>): <code>Server:
4061 Apache/2.4.2</code></dd>
4063 <dt><code>ServerTokens OS</code></dt>
4065 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4070 <p>This setting applies to the entire server, and cannot be
4071 enabled or disabled on a virtualhost-by-virtualhost basis.</p>
4073 <p>After version 2.0.44, this directive also controls the
4074 information presented by the <code class="directive"><a href="#serversignature">ServerSignature</a></code> directive.</p>
4076 <div class="note">Setting <code class="directive">ServerTokens</code> to less than
4077 <code>minimal</code> is not recommended because it makes it more
4078 difficult to debug interoperational problems. Also note that
4079 disabling the Server: header does nothing at all to make your
4080 server more secure; the idea of "security through obscurity"
4081 is a myth and leads to a false sense of safety.</div>
4086 <li><code class="directive"><a href="#serversignature">ServerSignature</a></code></li>
4089 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4090 <div class="directive-section"><h2><a name="SetHandler" id="SetHandler">SetHandler</a> <a name="sethandler" id="sethandler">Directive</a></h2>
4091 <table class="directive">
4092 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be processed by a
4094 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetHandler <var>handler-name</var>|None</code></td></tr>
4095 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4096 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4097 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4098 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4100 <p>When placed into an <code>.htaccess</code> file or a
4101 <code class="directive"><a href="#directory"><Directory></a></code> or
4102 <code class="directive"><a href="#location"><Location></a></code>
4103 section, this directive forces all matching files to be parsed
4104 through the <a href="../handler.html">handler</a> given by
4105 <var>handler-name</var>. For example, if you had a directory you
4106 wanted to be parsed entirely as imagemap rule files, regardless
4107 of extension, you might put the following into an
4108 <code>.htaccess</code> file in that directory:</p>
4110 <pre class="prettyprint lang-config">SetHandler imap-file</pre>
4113 <p>Another example: if you wanted to have the server display a
4114 status report whenever a URL of
4115 <code>http://servername/status</code> was called, you might put
4116 the following into <code>httpd.conf</code>:</p>
4118 <pre class="prettyprint lang-config"><Location "/status">
4119 SetHandler server-status
4120 </Location></pre>
4123 <p>You could also use this directive to configure a particular
4124 handler for files with a particular file extension. For example:</p>
4126 <pre class="prettyprint lang-config"><FilesMatch \.php$>
4127 SetHandler application/x-httpd-php
4128 </FilesMatch></pre>
4131 <p>You can override an earlier defined <code class="directive">SetHandler</code>
4132 directive by using the value <code>None</code>.</p>
4134 <div class="note"><h3>Note</h3>
4135 <p>Because <code class="directive">SetHandler</code> overrides default handlers,
4136 normal behavior such as handling of URLs ending in a slash (/) as
4137 directories or index files is suppressed.</p></div>
4141 <li><code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code></li>
4144 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4145 <div class="directive-section"><h2><a name="SetInputFilter" id="SetInputFilter">SetInputFilter</a> <a name="setinputfilter" id="setinputfilter">Directive</a></h2>
4146 <table class="directive">
4147 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process client requests and POST
4149 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetInputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4150 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4151 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4152 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4153 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4155 <p>The <code class="directive">SetInputFilter</code> directive sets the
4156 filter or filters which will process client requests and POST
4157 input when they are received by the server. This is in addition to
4158 any filters defined elsewhere, including the
4159 <code class="directive"><a href="../mod/mod_mime.html#addinputfilter">AddInputFilter</a></code>
4162 <p>If more than one filter is specified, they must be separated
4163 by semicolons in the order in which they should process the
4168 <li><a href="../filter.html">Filters</a> documentation</li>
4171 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4172 <div class="directive-section"><h2><a name="SetOutputFilter" id="SetOutputFilter">SetOutputFilter</a> <a name="setoutputfilter" id="setoutputfilter">Directive</a></h2>
4173 <table class="directive">
4174 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process responses from the
4176 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4177 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4178 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4179 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4180 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4182 <p>The <code class="directive">SetOutputFilter</code> directive sets the filters
4183 which will process responses from the server before they are
4184 sent to the client. This is in addition to any filters defined
4185 elsewhere, including the
4186 <code class="directive"><a href="../mod/mod_mime.html#addoutputfilter">AddOutputFilter</a></code>
4189 <p>For example, the following configuration will process all files
4190 in the <code>/www/data/</code> directory for server-side
4193 <pre class="prettyprint lang-config"><Directory "/www/data/">
4194 SetOutputFilter INCLUDES
4195 </Directory></pre>
4198 <p>If more than one filter is specified, they must be separated
4199 by semicolons in the order in which they should process the
4204 <li><a href="../filter.html">Filters</a> documentation</li>
4207 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4208 <div class="directive-section"><h2><a name="TimeOut" id="TimeOut">TimeOut</a> <a name="timeout" id="timeout">Directive</a></h2>
4209 <table class="directive">
4210 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for
4211 certain events before failing a request</td></tr>
4212 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TimeOut <var>seconds</var></code></td></tr>
4213 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TimeOut 60</code></td></tr>
4214 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4215 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4216 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4218 <p>The <code class="directive">TimeOut</code> directive defines the length
4219 of time Apache httpd will wait for I/O in various circumstances:</p>
4222 <li>When reading data from the client, the length of time to
4223 wait for a TCP packet to arrive if the read buffer is
4226 <li>When writing data to the client, the length of time to wait
4227 for an acknowledgement of a packet if the send buffer is
4230 <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>,
4231 the length of time to wait for output from a CGI script.</li>
4233 <li>In <code class="module"><a href="../mod/mod_ext_filter.html">mod_ext_filter</a></code>, the length of time to
4234 wait for output from a filtering process.</li>
4236 <li>In <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>, the default timeout value if
4237 <code class="directive"><a href="../mod/mod_proxy.html#proxytimeout">ProxyTimeout</a></code> is not
4243 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4244 <div class="directive-section"><h2><a name="TraceEnable" id="TraceEnable">TraceEnable</a> <a name="traceenable" id="traceenable">Directive</a></h2>
4245 <table class="directive">
4246 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines the behavior on <code>TRACE</code> requests</td></tr>
4247 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TraceEnable <var>[on|off|extended]</var></code></td></tr>
4248 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TraceEnable on</code></td></tr>
4249 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4250 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4251 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4253 <p>This directive overrides the behavior of <code>TRACE</code> for both
4254 the core server and <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>. The default
4255 <code>TraceEnable on</code> permits <code>TRACE</code> requests per
4256 RFC 2616, which disallows any request body to accompany the request.
4257 <code>TraceEnable off</code> causes the core server and
4258 <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> to return a <code>405</code> (Method not
4259 allowed) error to the client.</p>
4261 <p>Finally, for testing and diagnostic purposes only, request
4262 bodies may be allowed using the non-compliant <code>TraceEnable
4263 extended</code> directive. The core (as an origin server) will
4264 restrict the request body to 64k (plus 8k for chunk headers if
4265 <code>Transfer-Encoding: chunked</code> is used). The core will
4266 reflect the full headers and all chunk headers with the response
4267 body. As a proxy server, the request body is not restricted to 64k.</p>
4269 <div class="note"><h3>Note</h3>
4270 <p>Despite claims to the contrary, <code>TRACE</code> is not
4271 a security vulnerability and there is no viable reason for
4272 it to be disabled. Doing so necessarily makes your server
4277 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4278 <div class="directive-section"><h2><a name="UnDefine" id="UnDefine">UnDefine</a> <a name="undefine" id="undefine">Directive</a></h2>
4279 <table class="directive">
4280 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Undefine the existence of a variable</td></tr>
4281 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UnDefine <var>parameter-name</var></code></td></tr>
4282 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4283 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4284 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4286 <p>Undoes the effect of a <code class="directive"><a href="#define">Define</a></code> or
4287 of passing a <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</p>
4288 <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
4289 <code>-D</code> arguments in any startup scripts.</p>
4292 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4293 <div class="directive-section"><h2><a name="UseCanonicalName" id="UseCanonicalName">UseCanonicalName</a> <a name="usecanonicalname" id="usecanonicalname">Directive</a></h2>
4294 <table class="directive">
4295 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own name and
4297 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalName On|Off|DNS</code></td></tr>
4298 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalName Off</code></td></tr>
4299 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4300 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4301 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4303 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4304 URL -- that is, a URL that refers back to the same server. With
4305 <code>UseCanonicalName On</code> Apache httpd will use the hostname and port
4306 specified in the <code class="directive"><a href="#servername">ServerName</a></code>
4307 directive to construct the canonical name for the server. This name
4308 is used in all self-referential URLs, and for the values of
4309 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>
4311 <p>With <code>UseCanonicalName Off</code> Apache httpd will form
4312 self-referential URLs using the hostname and port supplied by
4313 the client if any are supplied (otherwise it will use the
4314 canonical name, as defined above). These values are the same
4315 that are used to implement <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
4316 and are available with the same clients. The CGI variables
4317 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
4318 constructed from the client supplied values as well.</p>
4320 <p>An example where this may be useful is on an intranet server
4321 where you have users connecting to the machine using short
4322 names such as <code>www</code>. You'll notice that if the users
4323 type a shortname, and a URL which is a directory, such as
4324 <code>http://www/splat</code>, <em>without the trailing
4325 slash</em> then Apache httpd will redirect them to
4326 <code>http://www.example.com/splat/</code>. If you have
4327 authentication enabled, this will cause the user to have to
4328 authenticate twice (once for <code>www</code> and once again
4329 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">
4330 the FAQ on this subject for more information</a>). But if
4331 <code class="directive">UseCanonicalName</code> is set <code>Off</code>, then
4332 Apache httpd will redirect to <code>http://www/splat/</code>.</p>
4334 <p>There is a third option, <code>UseCanonicalName DNS</code>,
4335 which is intended for use with mass IP-based virtual hosting to
4336 support ancient clients that do not provide a
4337 <code>Host:</code> header. With this option Apache httpd does a
4338 reverse DNS lookup on the server IP address that the client
4339 connected to in order to work out self-referential URLs.</p>
4341 <div class="warning"><h3>Warning</h3>
4342 <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>
4343 they may be broken by this option. The client is essentially free
4344 to give whatever value they want as a hostname. But if the CGI is
4345 only using <code>SERVER_NAME</code> to construct self-referential URLs
4346 then it should be just fine.</p>
4351 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
4352 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4353 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4356 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4357 <div class="directive-section"><h2><a name="UseCanonicalPhysicalPort" id="UseCanonicalPhysicalPort">UseCanonicalPhysicalPort</a> <a name="usecanonicalphysicalport" id="usecanonicalphysicalport">Directive</a></h2>
4358 <table class="directive">
4359 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own port</td></tr>
4360 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalPhysicalPort On|Off</code></td></tr>
4361 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalPhysicalPort Off</code></td></tr>
4362 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4363 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4364 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4366 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4367 URL -- that is, a URL that refers back to the same server. With
4368 <code>UseCanonicalPhysicalPort On</code> Apache httpd will, when
4369 constructing the canonical port for the server to honor
4370 the <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> directive,
4371 provide the actual physical port number being used by this request
4372 as a potential port. With <code>UseCanonicalPhysicalPort Off</code>
4373 Apache httpd will not ever use the actual physical port number, instead
4374 relying on all configured information to construct a valid port number.</p>
4376 <div class="note"><h3>Note</h3>
4377 <p>The ordering of the lookup when the physical port is used is as
4380 <dt><code>UseCanonicalName On</code></dt>
4383 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4384 <li>Physical port</li>
4385 <li>Default port</li>
4388 <dt><code>UseCanonicalName Off | DNS</code></dt>
4391 <li>Parsed port from <code>Host:</code> header</li>
4392 <li>Physical port</li>
4393 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4394 <li>Default port</li>
4399 <p>With <code>UseCanonicalPhysicalPort Off</code>, the
4400 physical ports are removed from the ordering.</p>
4406 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
4407 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4408 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></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="VirtualHost" id="VirtualHost"><VirtualHost></a> <a name="virtualhost" id="virtualhost">Directive</a></h2>
4413 <table class="directive">
4414 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only to a specific
4415 hostname or IP address</td></tr>
4416 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><VirtualHost
4417 <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
4418 ...> ... </VirtualHost></code></td></tr>
4419 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4420 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4421 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4423 <p><code class="directive"><VirtualHost></code> and
4424 <code></VirtualHost></code> are used to enclose a group of
4425 directives that will apply only to a particular virtual host. Any
4426 directive that is allowed in a virtual host context may be
4427 used. When the server receives a request for a document on a
4428 particular virtual host, it uses the configuration directives
4429 enclosed in the <code class="directive"><VirtualHost></code>
4430 section. <var>Addr</var> can be any of the following, optionally followed by
4431 a colon and a port number (or *):</p>
4434 <li>The IP address of the virtual host;</li>
4436 <li>A fully qualified domain name for the IP address of the
4437 virtual host (not recommended);</li>
4439 <li>The character <code>*</code>, which acts as a wildcard and matches
4440 any IP address.</li>
4442 <li>The string <code>_default_</code>, which is an alias for <code>*</code></li>
4446 <pre class="prettyprint lang-config"><VirtualHost 10.1.2.3:80>
4447 ServerAdmin webmaster@host.example.com
4448 DocumentRoot /www/docs/host.example.com
4449 ServerName host.example.com
4450 ErrorLog logs/host.example.com-error_log
4451 TransferLog logs/host.example.com-access_log
4452 </VirtualHost></pre>
4456 <p>IPv6 addresses must be specified in square brackets because
4457 the optional port number could not be determined otherwise. An
4458 IPv6 example is shown below:</p>
4460 <pre class="prettyprint lang-config"><VirtualHost [2001:db8::a00:20ff:fea7:ccea]:80>
4461 ServerAdmin webmaster@host.example.com
4462 DocumentRoot /www/docs/host.example.com
4463 ServerName host.example.com
4464 ErrorLog logs/host.example.com-error_log
4465 TransferLog logs/host.example.com-access_log
4466 </VirtualHost></pre>
4469 <p>Each Virtual Host must correspond to a different IP address,
4470 different port number or a different host name for the server,
4471 in the former case the server machine must be configured to
4472 accept IP packets for multiple addresses. (If the machine does
4473 not have multiple network interfaces, then this can be
4474 accomplished with the <code>ifconfig alias</code> command -- if
4475 your OS supports it).</p>
4477 <div class="note"><h3>Note</h3>
4478 <p>The use of <code class="directive"><VirtualHost></code> does
4479 <strong>not</strong> affect what addresses Apache httpd listens on. You
4480 may need to ensure that Apache httpd is listening on the correct addresses
4481 using <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>.</p>
4484 <p>A <code class="directive"><a href="#servername">ServerName</a></code> should be
4485 specified inside each <code class="directive"><VirtualHost></code> block. If it is absent, the
4486 <code class="directive"><a href="#servername">ServerName</a></code> from the "main"
4487 server configuration will be inherited.</p>
4489 <p>When a request is received, the server first maps it to the best matching
4490 <code class="directive"><VirtualHost></code> based on the local
4491 IP address and port combination only. Non-wildcards have a higher
4492 precedence. If no match based on IP and port occurs at all, the
4493 "main" server configuration is used.</p>
4495 <p>If multiple virtual hosts contain the best matching IP address and port,
4496 the server selects from these virtual hosts the best match based on the
4497 requested hostname. If no matching name-based virtual host is found,
4498 then the first listed virtual host that matched the IP address will be
4499 used. As a consequence, the first listed virtual host for a given IP address
4500 and port combination is default virtual host for that IP and port
4503 <div class="warning"><h3>Security</h3>
4504 <p>See the <a href="../misc/security_tips.html">security tips</a>
4505 document for details on why your security could be compromised if the
4506 directory where log files are stored is writable by anyone other
4507 than the user that starts the server.</p>
4512 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4513 <li><a href="../dns-caveats.html">Issues Regarding DNS and
4514 Apache HTTP Server</a></li>
4515 <li><a href="../bind.html">Setting
4516 which addresses and ports Apache HTTP Server uses</a></li>
4517 <li><a href="../sections.html">How <Directory>, <Location>
4518 and <Files> sections work</a> for an explanation of how these
4519 different sections are combined when a request is received</li>
4522 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4523 <div class="directive-section"><h2><a name="Warning" id="Warning">Warning</a> <a name="warning" id="warning">Directive</a></h2>
4524 <table class="directive">
4525 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Warn from configuration parsing with a custom message</td></tr>
4526 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Warning <var>message</var></code></td></tr>
4527 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4528 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4529 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4530 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.5 and later</td></tr>
4532 <p>If an issue can be detected from within the configuration, this
4533 directive can be used to generate a custom warning message. The
4534 configuration parsing is not halted. The typical use it to check
4535 whether some user define options are set, and warn if not.</p>
4537 <pre class="prettyprint lang-config"># Example
4538 # tell when ReverseProxy is not set
4539 <IfDefine !ReverseProxy>
4540 Warning "reverse proxy is not started, hope this is okay!"
4543 <IfDefine ReverseProxy>
4544 # define custom proxy configuration
4545 </IfDefine></pre>
4551 <div class="bottomlang">
4552 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
4553 <a href="../en/mod/core.html" title="English"> en </a> |
4554 <a href="../es/mod/core.html" hreflang="es" rel="alternate" title="Español"> es </a> |
4555 <a href="../fr/mod/core.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
4556 <a href="../ja/mod/core.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
4557 <a href="../tr/mod/core.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p>
4558 </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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