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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="#cgipassauth">CGIPassAuth</a></li>
49 <li><img alt="" src="../images/down.gif" /> <a href="#contentdigest">ContentDigest</a></li>
50 <li><img alt="" src="../images/down.gif" /> <a href="#defaultruntimedir">DefaultRuntimeDir</a></li>
51 <li><img alt="" src="../images/down.gif" /> <a href="#defaulttype">DefaultType</a></li>
52 <li><img alt="" src="../images/down.gif" /> <a href="#define">Define</a></li>
53 <li><img alt="" src="../images/down.gif" /> <a href="#directory"><Directory></a></li>
54 <li><img alt="" src="../images/down.gif" /> <a href="#directorymatch"><DirectoryMatch></a></li>
55 <li><img alt="" src="../images/down.gif" /> <a href="#documentroot">DocumentRoot</a></li>
56 <li><img alt="" src="../images/down.gif" /> <a href="#else"><Else></a></li>
57 <li><img alt="" src="../images/down.gif" /> <a href="#elseif"><ElseIf></a></li>
58 <li><img alt="" src="../images/down.gif" /> <a href="#enablemmap">EnableMMAP</a></li>
59 <li><img alt="" src="../images/down.gif" /> <a href="#enablesendfile">EnableSendfile</a></li>
60 <li><img alt="" src="../images/down.gif" /> <a href="#error">Error</a></li>
61 <li><img alt="" src="../images/down.gif" /> <a href="#errordocument">ErrorDocument</a></li>
62 <li><img alt="" src="../images/down.gif" /> <a href="#errorlog">ErrorLog</a></li>
63 <li><img alt="" src="../images/down.gif" /> <a href="#errorlogformat">ErrorLogFormat</a></li>
64 <li><img alt="" src="../images/down.gif" /> <a href="#extendedstatus">ExtendedStatus</a></li>
65 <li><img alt="" src="../images/down.gif" /> <a href="#fileetag">FileETag</a></li>
66 <li><img alt="" src="../images/down.gif" /> <a href="#files"><Files></a></li>
67 <li><img alt="" src="../images/down.gif" /> <a href="#filesmatch"><FilesMatch></a></li>
68 <li><img alt="" src="../images/down.gif" /> <a href="#forcetype">ForceType</a></li>
69 <li><img alt="" src="../images/down.gif" /> <a href="#gprofdir">GprofDir</a></li>
70 <li><img alt="" src="../images/down.gif" /> <a href="#hostnamelookups">HostnameLookups</a></li>
71 <li><img alt="" src="../images/down.gif" /> <a href="#if"><If></a></li>
72 <li><img alt="" src="../images/down.gif" /> <a href="#ifdefine"><IfDefine></a></li>
73 <li><img alt="" src="../images/down.gif" /> <a href="#ifmodule"><IfModule></a></li>
74 <li><img alt="" src="../images/down.gif" /> <a href="#include">Include</a></li>
75 <li><img alt="" src="../images/down.gif" /> <a href="#includeoptional">IncludeOptional</a></li>
76 <li><img alt="" src="../images/down.gif" /> <a href="#keepalive">KeepAlive</a></li>
77 <li><img alt="" src="../images/down.gif" /> <a href="#keepalivetimeout">KeepAliveTimeout</a></li>
78 <li><img alt="" src="../images/down.gif" /> <a href="#limit"><Limit></a></li>
79 <li><img alt="" src="../images/down.gif" /> <a href="#limitexcept"><LimitExcept></a></li>
80 <li><img alt="" src="../images/down.gif" /> <a href="#limitinternalrecursion">LimitInternalRecursion</a></li>
81 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestbody">LimitRequestBody</a></li>
82 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfields">LimitRequestFields</a></li>
83 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfieldsize">LimitRequestFieldSize</a></li>
84 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestline">LimitRequestLine</a></li>
85 <li><img alt="" src="../images/down.gif" /> <a href="#limitxmlrequestbody">LimitXMLRequestBody</a></li>
86 <li><img alt="" src="../images/down.gif" /> <a href="#location"><Location></a></li>
87 <li><img alt="" src="../images/down.gif" /> <a href="#locationmatch"><LocationMatch></a></li>
88 <li><img alt="" src="../images/down.gif" /> <a href="#loglevel">LogLevel</a></li>
89 <li><img alt="" src="../images/down.gif" /> <a href="#logleveloverride">LogLevelOverride</a></li>
90 <li><img alt="" src="../images/down.gif" /> <a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></li>
91 <li><img alt="" src="../images/down.gif" /> <a href="#maxrangeoverlaps">MaxRangeOverlaps</a></li>
92 <li><img alt="" src="../images/down.gif" /> <a href="#maxrangereversals">MaxRangeReversals</a></li>
93 <li><img alt="" src="../images/down.gif" /> <a href="#maxranges">MaxRanges</a></li>
94 <li><img alt="" src="../images/down.gif" /> <a href="#mergetrailers">MergeTrailers</a></li>
95 <li><img alt="" src="../images/down.gif" /> <a href="#mutex">Mutex</a></li>
96 <li><img alt="" src="../images/down.gif" /> <a href="#namevirtualhost">NameVirtualHost</a></li>
97 <li><img alt="" src="../images/down.gif" /> <a href="#options">Options</a></li>
98 <li><img alt="" src="../images/down.gif" /> <a href="#protocol">Protocol</a></li>
99 <li><img alt="" src="../images/down.gif" /> <a href="#registerhttpmethod">RegisterHttpMethod</a></li>
100 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitcpu">RLimitCPU</a></li>
101 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitmem">RLimitMEM</a></li>
102 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitnproc">RLimitNPROC</a></li>
103 <li><img alt="" src="../images/down.gif" /> <a href="#scriptinterpretersource">ScriptInterpreterSource</a></li>
104 <li><img alt="" src="../images/down.gif" /> <a href="#seerequesttail">SeeRequestTail</a></li>
105 <li><img alt="" src="../images/down.gif" /> <a href="#serveradmin">ServerAdmin</a></li>
106 <li><img alt="" src="../images/down.gif" /> <a href="#serveralias">ServerAlias</a></li>
107 <li><img alt="" src="../images/down.gif" /> <a href="#servername">ServerName</a></li>
108 <li><img alt="" src="../images/down.gif" /> <a href="#serverpath">ServerPath</a></li>
109 <li><img alt="" src="../images/down.gif" /> <a href="#serverroot">ServerRoot</a></li>
110 <li><img alt="" src="../images/down.gif" /> <a href="#serversignature">ServerSignature</a></li>
111 <li><img alt="" src="../images/down.gif" /> <a href="#servertokens">ServerTokens</a></li>
112 <li><img alt="" src="../images/down.gif" /> <a href="#sethandler">SetHandler</a></li>
113 <li><img alt="" src="../images/down.gif" /> <a href="#setinputfilter">SetInputFilter</a></li>
114 <li><img alt="" src="../images/down.gif" /> <a href="#setoutputfilter">SetOutputFilter</a></li>
115 <li><img alt="" src="../images/down.gif" /> <a href="#timeout">TimeOut</a></li>
116 <li><img alt="" src="../images/down.gif" /> <a href="#traceenable">TraceEnable</a></li>
117 <li><img alt="" src="../images/down.gif" /> <a href="#undefine">UnDefine</a></li>
118 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalname">UseCanonicalName</a></li>
119 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></li>
120 <li><img alt="" src="../images/down.gif" /> <a href="#virtualhost"><VirtualHost></a></li>
121 <li><img alt="" src="../images/down.gif" /> <a href="#warning">Warning</a></li>
123 <ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div>
125 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
126 <div class="directive-section"><h2><a name="AcceptFilter" id="AcceptFilter">AcceptFilter</a> <a name="acceptfilter" id="acceptfilter">Directive</a></h2>
127 <table class="directive">
128 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures optimizations for a Protocol's Listener Sockets</td></tr>
129 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptFilter <var>protocol</var> <var>accept_filter</var></code></td></tr>
130 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
131 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
132 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
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="CGIPassAuth" id="CGIPassAuth">CGIPassAuth</a> <a name="cgipassauth" id="cgipassauth">Directive</a></h2>
631 <table class="directive">
632 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables passing HTTP authorization headers to scripts as CGI
634 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CGIPassAuth On|Off</code></td></tr>
635 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>CGIPassAuth Off</code></td></tr>
636 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
637 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig</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>
640 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.5.0 and later</td></tr>
642 <p><code class="directive">CGIPassAuth</code> allows scripts access to HTTP
643 authorization headers such as <code>Authorization</code>, which is
644 required for scripts that implement HTTP Basic authentication.
645 Normally these HTTP headers are hidden from scripts, as it allows
646 scripts to see user ids and passwords used to access the server when
647 HTTP Basic authentication is enabled in the web server. This directive
648 should be used when scripts are allowed to implement HTTP Basic
651 <p>This directive can be used instead of the compile-time setting
652 <code>SECURITY_HOLE_PASS_AUTHORIZATION</code> which has been available
653 in previous versions of Apache HTTP Server.</p>
655 <p>The setting is respected by any modules which use
656 <code>ap_add_common_vars()</code>, such as <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>,
657 <code class="module"><a href="../mod/mod_cgid.html">mod_cgid</a></code>, <code class="module"><a href="../mod/mod_proxy_fcgi.html">mod_proxy_fcgi</a></code>,
658 <code class="module"><a href="../mod/mod_proxy_scgi.html">mod_proxy_scgi</a></code>, and so on. Notably, it affects
659 modules which don't handle the request in the usual sense but
660 still use this API; examples of this are <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
661 and <code class="module"><a href="../mod/mod_ext_filter.html">mod_ext_filter</a></code>. Third-party modules that don't
662 use <code>ap_add_common_vars()</code> may choose to respect the setting
666 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
667 <div class="directive-section"><h2><a name="ContentDigest" id="ContentDigest">ContentDigest</a> <a name="contentdigest" id="contentdigest">Directive</a></h2>
668 <table class="directive">
669 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables the generation of <code>Content-MD5</code> HTTP Response
671 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ContentDigest On|Off</code></td></tr>
672 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ContentDigest Off</code></td></tr>
673 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
674 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
675 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
676 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
678 <p>This directive enables the generation of
679 <code>Content-MD5</code> headers as defined in RFC1864
680 respectively RFC2616.</p>
682 <p>MD5 is an algorithm for computing a "message digest"
683 (sometimes called "fingerprint") of arbitrary-length data, with
684 a high degree of confidence that any alterations in the data
685 will be reflected in alterations in the message digest.</p>
687 <p>The <code>Content-MD5</code> header provides an end-to-end
688 message integrity check (MIC) of the entity-body. A proxy or
689 client may check this header for detecting accidental
690 modification of the entity-body in transit. Example header:</p>
692 <div class="example"><p><code>
693 Content-MD5: AuLb7Dp1rqtRtxz2m9kRpA==
696 <p>Note that this can cause performance problems on your server
697 since the message digest is computed on every request (the
698 values are not cached).</p>
700 <p><code>Content-MD5</code> is only sent for documents served
701 by the <code class="module"><a href="../mod/core.html">core</a></code>, and not by any module. For example,
702 SSI documents, output from CGI scripts, and byte range responses
703 do not have this header.</p>
706 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
707 <div class="directive-section"><h2><a name="DefaultRuntimeDir" id="DefaultRuntimeDir">DefaultRuntimeDir</a> <a name="defaultruntimedir" id="defaultruntimedir">Directive</a></h2>
708 <table class="directive">
709 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server run-time files</td></tr>
710 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultRuntimeDir <var>directory-path</var></code></td></tr>
711 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultRuntimeDir DEFAULT_REL_RUNTIMEDIR (logs/)</code></td></tr>
712 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
713 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
714 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
715 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.4.2 and later</td></tr>
717 <p>The <code class="directive">DefaultRuntimeDir</code> directive sets the
718 directory in which the server will create various run-time files
719 (shared memory, locks, etc.). If set as a relative path, the full path
720 will be relative to <code class="directive">ServerRoot</code>.</p>
722 <p><strong>Example</strong></p>
723 <pre class="prettyprint lang-config">DefaultRuntimeDir scratch/</pre>
726 <p>The default location of <code class="directive">DefaultRuntimeDir</code> may be
727 modified by changing the <code>DEFAULT_REL_RUNTIMEDIR</code> #define
730 <p>Note: <code class="directive">ServerRoot</code> should be specified before this
731 directive is used, otherwise the default value of <code class="directive">ServerRoot</code>
732 would be used to set the base directory.</p>
737 <li><a href="../misc/security_tips.html#serverroot">the
738 security tips</a> for information on how to properly set
739 permissions on the <code class="directive">ServerRoot</code></li>
742 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
743 <div class="directive-section"><h2><a name="DefaultType" id="DefaultType">DefaultType</a> <a name="defaulttype" id="defaulttype">Directive</a></h2>
744 <table class="directive">
745 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>This directive has no effect other than to emit warnings
746 if the value is not <code>none</code>. In prior versions, DefaultType
747 would specify a default media type to assign to response content for
748 which no other media type configuration could be found.
750 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultType <var>media-type|none</var></code></td></tr>
751 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultType none</code></td></tr>
752 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
753 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
754 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
755 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
756 <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.
759 <p>This directive has been disabled. For backwards compatibility
760 of configuration files, it may be specified with the value
761 <code>none</code>, meaning no default media type. For example:</p>
763 <pre class="prettyprint lang-config">DefaultType None</pre>
766 <p><code>DefaultType None</code> is only available in
767 httpd-2.2.7 and later.</p>
769 <p>Use the mime.types configuration file and the
770 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code> to configure media
771 type assignments via file extensions, or the
772 <code class="directive"><a href="#forcetype">ForceType</a></code> directive to configure
773 the media type for specific resources. Otherwise, the server will
774 send the response without a Content-Type header field and the
775 recipient may attempt to guess the media type.</p>
778 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
779 <div class="directive-section"><h2><a name="Define" id="Define">Define</a> <a name="define" id="define">Directive</a></h2>
780 <table class="directive">
781 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Define a variable</td></tr>
782 <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>
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>In its one parameter form, <code class="directive">Define</code> is equivalent
788 to passing the <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>. It
789 can be used to toggle the use of
790 <code class="directive"><a href="#ifdefine"><IfDefine></a></code> sections
791 without needing to alter <code>-D</code> arguments in any startup
794 <p>In addition to that, if the second parameter is given, a config variable
795 is set to this value. The variable can be used in the configuration using
796 the <code>${VAR}</code> syntax. The variable is always globally defined
797 and not limited to the scope of the surrounding config section.</p>
799 <pre class="prettyprint lang-config"><IfDefine TEST>
800 Define servername test.example.com
802 <IfDefine !TEST>
803 Define servername www.example.com
807 DocumentRoot /var/www/${servername}/htdocs</pre>
810 <p>Variable names may not contain colon ":" characters, to avoid clashes
811 with <code class="directive"><a href="../mod/mod_rewrite.html#rewritemap">RewriteMap</a></code>'s syntax.</p>
813 <p>While this directive is supported in virtual host context,
814 the changes it makes are visible to any later configuration
815 directives, beyond any enclosing virtual host</p>
818 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
819 <div class="directive-section"><h2><a name="Directory" id="Directory"><Directory></a> <a name="directory" id="directory">Directive</a></h2>
820 <table class="directive">
821 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose a group of directives that apply only to the
822 named file-system directory, sub-directories, and their contents.</td></tr>
823 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Directory <var>directory-path</var>>
824 ... </Directory></code></td></tr>
825 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
826 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
827 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
829 <p><code class="directive"><Directory></code> and
830 <code></Directory></code> are used to enclose a group of
831 directives that will apply only to the named directory,
832 sub-directories of that directory, and the files within the respective
833 directories. Any directive that is allowed
834 in a directory context may be used. <var>Directory-path</var> is
835 either the full path to a directory, or a wild-card string using
836 Unix shell-style matching. In a wild-card string, <code>?</code> matches
837 any single character, and <code>*</code> matches any sequences of
838 characters. You may also use <code>[]</code> character ranges. None
839 of the wildcards match a `/' character, so <code><Directory
840 /*/public_html></code> will not match
841 <code>/home/user/public_html</code>, but <code><Directory
842 /home/*/public_html></code> will match. Example:</p>
844 <pre class="prettyprint lang-config"><Directory "/usr/local/httpd/htdocs">
845 Options Indexes FollowSymLinks
846 </Directory></pre>
850 <p>Be careful with the <var>directory-path</var> arguments:
851 They have to literally match the filesystem path which Apache httpd uses
852 to access the files. Directives applied to a particular
853 <code><Directory></code> will not apply to files accessed from
854 that same directory via a different path, such as via different symbolic
858 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular
859 expressions</a> can also be used, with the addition of the
860 <code>~</code> character. For example:</p>
862 <pre class="prettyprint lang-config"><Directory ~ "^/www/[0-9]{3}">
864 </Directory></pre>
867 <p>would match directories in <code>/www/</code> that consisted of
870 <p>If multiple (non-regular expression) <code class="directive"><Directory></code> sections
871 match the directory (or one of its parents) containing a document,
872 then the directives are applied in the order of shortest match
873 first, interspersed with the directives from the <a href="#accessfilename">.htaccess</a> files. For example,
876 <pre class="prettyprint lang-config"><Directory />
880 <Directory "/home">
881 AllowOverride FileInfo
882 </Directory></pre>
885 <p>for access to the document <code>/home/web/dir/doc.html</code>
889 <li>Apply directive <code>AllowOverride None</code>
890 (disabling <code>.htaccess</code> files).</li>
892 <li>Apply directive <code>AllowOverride FileInfo</code> (for
893 directory <code>/home</code>).</li>
895 <li>Apply any <code>FileInfo</code> directives in
896 <code>/home/.htaccess</code>, <code>/home/web/.htaccess</code> and
897 <code>/home/web/dir/.htaccess</code> in that order.</li>
900 <p>Regular expressions are not considered until after all of the
901 normal sections have been applied. Then all of the regular
902 expressions are tested in the order they appeared in the
903 configuration file. For example, with</p>
905 <pre class="prettyprint lang-config"><Directory ~ "abc$">
906 # ... directives here ...
907 </Directory></pre>
910 <p>the regular expression section won't be considered until after
911 all normal <code class="directive"><Directory></code>s and
912 <code>.htaccess</code> files have been applied. Then the regular
913 expression will match on <code>/home/abc/public_html/abc</code> and
914 the corresponding <code class="directive"><Directory></code> will
917 <p><strong>Note that the default access for
918 <code><Directory /></code> is to permit all access.
919 This means that Apache httpd will serve any file mapped from an URL. It is
920 recommended that you change this with a block such
923 <pre class="prettyprint lang-config"><Directory />
925 </Directory></pre>
928 <p><strong>and then override this for directories you
929 <em>want</em> accessible. See the <a href="../misc/security_tips.html">Security Tips</a> page for more
930 details.</strong></p>
932 <p>The directory sections occur in the <code>httpd.conf</code> file.
933 <code class="directive"><Directory></code> directives
934 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>
938 <li><a href="../sections.html">How <Directory>,
939 <Location> and <Files> sections work</a> for an
940 explanation of how these different sections are combined when a
941 request is received</li>
944 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
945 <div class="directive-section"><h2><a name="DirectoryMatch" id="DirectoryMatch"><DirectoryMatch></a> <a name="directorymatch" id="directorymatch">Directive</a></h2>
946 <table class="directive">
947 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose directives that apply to
948 the contents of file-system directories matching a regular expression.</td></tr>
949 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><DirectoryMatch <var>regex</var>>
950 ... </DirectoryMatch></code></td></tr>
951 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
952 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
953 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
955 <p><code class="directive"><DirectoryMatch></code> and
956 <code></DirectoryMatch></code> are used to enclose a group
957 of directives which will apply only to the named directory (and the files within),
958 the same as <code class="directive"><a href="#directory"><Directory></a></code>.
959 However, it takes as an argument a
960 <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>. For example:</p>
962 <pre class="prettyprint lang-config"><DirectoryMatch "^/www/(.+/)?[0-9]{3}">
964 </DirectoryMatch></pre>
967 <p>would match directories in <code>/www/</code> that consisted of three
970 <div class="note"><h3>Compatability</h3>
971 Prior to 2.3.9, this directive implicitly applied to sub-directories
972 (like <code class="directive"><a href="#directory"><Directory></a></code>) and
973 could not match the end of line symbol ($). In 2.3.9 and later,
974 only directories that match the expression are affected by the enclosed
978 <div class="note"><h3>Trailing Slash</h3>
979 This directive applies to requests for directories that may or may
980 not end in a trailing slash, so expressions that are anchored to the
981 end of line ($) must be written with care.
984 <p>From 2.4.8 onwards, named groups and backreferences are captured and
985 written to the environment with the corresponding name prefixed with
986 "MATCH_" and in upper case. This allows elements of paths to be referenced
987 from within <a href="../expr.html">expressions</a> and modules like
988 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
989 (unnamed) backreferences are ignored. Use named groups instead.</p>
991 <pre class="prettyprint lang-config"><DirectoryMatch ^/var/www/combined/(?<sitename>[^/]+)>
992 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
993 </DirectoryMatch></pre>
998 <li><code class="directive"><a href="#directory"><Directory></a></code> for
999 a description of how regular expressions are mixed in with normal
1000 <code class="directive"><Directory></code>s</li>
1001 <li><a href="../sections.html">How <Directory>, <Location> and
1002 <Files> sections work</a> for an explanation of how these different
1003 sections are combined when a request is received</li>
1006 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1007 <div class="directive-section"><h2><a name="DocumentRoot" id="DocumentRoot">DocumentRoot</a> <a name="documentroot" id="documentroot">Directive</a></h2>
1008 <table class="directive">
1009 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory that forms the main document tree visible
1010 from the web</td></tr>
1011 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DocumentRoot <var>directory-path</var></code></td></tr>
1012 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DocumentRoot /usr/local/apache/htdocs</code></td></tr>
1013 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1014 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1015 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1017 <p>This directive sets the directory from which <code class="program"><a href="../programs/httpd.html">httpd</a></code>
1018 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
1019 path from the requested URL to the document root to make the
1020 path to the document. Example:</p>
1022 <pre class="prettyprint lang-config">DocumentRoot "/usr/web"</pre>
1025 <p>then an access to
1026 <code>http://my.example.com/index.html</code> refers to
1027 <code>/usr/web/index.html</code>. If the <var>directory-path</var> is
1028 not absolute then it is assumed to be relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1030 <p>The <code class="directive">DocumentRoot</code> should be specified without
1031 a trailing slash.</p>
1035 <li><a href="../urlmapping.html#documentroot">Mapping URLs to Filesystem
1039 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1040 <div class="directive-section"><h2><a name="Else" id="Else"><Else></a> <a name="else" id="else">Directive</a></h2>
1041 <table class="directive">
1042 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if the condition of a
1043 previous <code class="directive"><a href="#if"><If></a></code> or
1044 <code class="directive"><a href="#elseif"><ElseIf></a></code> section is not
1045 satisfied by a request at runtime</td></tr>
1046 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Else> ... </Else></code></td></tr>
1047 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1048 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1049 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1050 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1052 <p>The <code class="directive"><Else></code> applies the enclosed
1053 directives if and only if the most recent
1054 <code class="directive"><If></code> or
1055 <code class="directive"><ElseIf></code> section
1056 in the same scope has not been applied.
1057 For example: In </p>
1059 <pre class="prettyprint lang-config"><If "-z req('Host')">
1067 <p> The <code class="directive"><If></code> would match HTTP/1.0
1068 requests without a <var>Host:</var> header and the
1069 <code class="directive"><Else></code> would match requests
1070 with a <var>Host:</var> header.</p>
1075 <li><code class="directive"><a href="#if"><If></a></code></li>
1076 <li><code class="directive"><a href="#elseif"><ElseIf></a></code></li>
1077 <li><a href="../sections.html">How <Directory>, <Location>,
1078 <Files> sections work</a> for an explanation of how these
1079 different sections are combined when a request is received.
1080 <code class="directive"><If></code>,
1081 <code class="directive"><ElseIf></code>, and
1082 <code class="directive"><Else></code> are applied last.</li>
1085 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1086 <div class="directive-section"><h2><a name="ElseIf" id="ElseIf"><ElseIf></a> <a name="elseif" id="elseif">Directive</a></h2>
1087 <table class="directive">
1088 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is satisfied
1089 by a request at runtime while the condition of a previous
1090 <code class="directive"><a href="#if"><If></a></code> or
1091 <code class="directive"><ElseIf></code> section is not
1093 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><ElseIf <var>expression</var>> ... </ElseIf></code></td></tr>
1094 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1095 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1096 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1097 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1099 <p>The <code class="directive"><ElseIf></code> applies the enclosed
1100 directives if and only if both the given condition evaluates to true and
1101 the most recent <code class="directive"><If></code> or
1102 <code class="directive"><ElseIf></code> section in the same scope has
1103 not been applied. For example: In </p>
1105 <pre class="prettyprint lang-config"><If "-R '10.1.0.0/16'">
1108 <ElseIf "-R '10.0.0.0/8'">
1116 <p>The <code class="directive"><ElseIf></code> would match if
1117 the remote address of a request belongs to the subnet 10.0.0.0/8 but
1118 not to the subnet 10.1.0.0/16.</p>
1123 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
1124 for a complete reference and more examples.</li>
1125 <li><code class="directive"><a href="#if"><If></a></code></li>
1126 <li><code class="directive"><a href="#else"><Else></a></code></li>
1127 <li><a href="../sections.html">How <Directory>, <Location>,
1128 <Files> sections work</a> for an explanation of how these
1129 different sections are combined when a request is received.
1130 <code class="directive"><If></code>,
1131 <code class="directive"><ElseIf></code>, and
1132 <code class="directive"><Else></code> are applied last.</li>
1135 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1136 <div class="directive-section"><h2><a name="EnableMMAP" id="EnableMMAP">EnableMMAP</a> <a name="enablemmap" id="enablemmap">Directive</a></h2>
1137 <table class="directive">
1138 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use memory-mapping to read files during delivery</td></tr>
1139 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableMMAP On|Off</code></td></tr>
1140 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableMMAP On</code></td></tr>
1141 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1142 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1143 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1144 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1146 <p>This directive controls whether the <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use
1147 memory-mapping if it needs to read the contents of a file during
1148 delivery. By default, when the handling of a request requires
1149 access to the data within a file -- for example, when delivering a
1150 server-parsed file using <code class="module"><a href="../mod/mod_include.html">mod_include</a></code> -- Apache httpd
1151 memory-maps the file if the OS supports it.</p>
1153 <p>This memory-mapping sometimes yields a performance improvement.
1154 But in some environments, it is better to disable the memory-mapping
1155 to prevent operational problems:</p>
1158 <li>On some multiprocessor systems, memory-mapping can reduce the
1159 performance of the <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</li>
1160 <li>Deleting or truncating a file while <code class="program"><a href="../programs/httpd.html">httpd</a></code>
1161 has it memory-mapped can cause <code class="program"><a href="../programs/httpd.html">httpd</a></code> to
1162 crash with a segmentation fault.
1166 <p>For server configurations that are vulnerable to these problems,
1167 you should disable memory-mapping of delivered files by specifying:</p>
1169 <pre class="prettyprint lang-config">EnableMMAP Off</pre>
1172 <p>For NFS mounted files, this feature may be disabled explicitly for
1173 the offending files by specifying:</p>
1175 <pre class="prettyprint lang-config"><Directory "/path-to-nfs-files">
1177 </Directory></pre>
1181 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1182 <div class="directive-section"><h2><a name="EnableSendfile" id="EnableSendfile">EnableSendfile</a> <a name="enablesendfile" id="enablesendfile">Directive</a></h2>
1183 <table class="directive">
1184 <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>
1185 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableSendfile On|Off</code></td></tr>
1186 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableSendfile Off</code></td></tr>
1187 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1188 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1189 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1190 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1191 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Default changed to Off in
1192 version 2.3.9.</td></tr>
1194 <p>This directive controls whether <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use the
1195 sendfile support from the kernel to transmit file contents to the client.
1196 By default, when the handling of a request requires no access
1197 to the data within a file -- for example, when delivering a
1198 static file -- Apache httpd uses sendfile to deliver the file contents
1199 without ever reading the file if the OS supports it.</p>
1201 <p>This sendfile mechanism avoids separate read and send operations,
1202 and buffer allocations. But on some platforms or within some
1203 filesystems, it is better to disable this feature to avoid
1204 operational problems:</p>
1207 <li>Some platforms may have broken sendfile support that the build
1208 system did not detect, especially if the binaries were built on
1209 another box and moved to such a machine with broken sendfile
1211 <li>On Linux the use of sendfile triggers TCP-checksum
1212 offloading bugs on certain networking cards when using IPv6.</li>
1213 <li>On Linux on Itanium, <code>sendfile</code> may be unable to handle
1214 files over 2GB in size.</li>
1215 <li>With a network-mounted <code class="directive"><a href="#documentroot">DocumentRoot</a></code> (e.g., NFS, SMB, CIFS, FUSE),
1216 the kernel may be unable to serve the network file through
1220 <p>For server configurations that are not vulnerable to these problems,
1221 you may enable this feature by specifying:</p>
1223 <pre class="prettyprint lang-config">EnableSendfile On</pre>
1226 <p>For network mounted files, this feature may be disabled explicitly
1227 for the offending files by specifying:</p>
1229 <pre class="prettyprint lang-config"><Directory "/path-to-nfs-files">
1231 </Directory></pre>
1233 <p>Please note that the per-directory and .htaccess configuration
1234 of <code class="directive">EnableSendfile</code> is not supported by
1235 <code class="module"><a href="../mod/mod_cache_disk.html">mod_cache_disk</a></code>.
1236 Only global definition of <code class="directive">EnableSendfile</code>
1237 is taken into account by the module.
1241 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1242 <div class="directive-section"><h2><a name="Error" id="Error">Error</a> <a name="error" id="error">Directive</a></h2>
1243 <table class="directive">
1244 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Abort configuration parsing with a custom error message</td></tr>
1245 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Error <var>message</var></code></td></tr>
1246 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1247 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1248 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1249 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.3.9 and later</td></tr>
1251 <p>If an error can be detected within the configuration, this
1252 directive can be used to generate a custom error message, and halt
1253 configuration parsing. The typical use is for reporting required
1254 modules which are missing from the configuration.</p>
1256 <pre class="prettyprint lang-config"># Example
1257 # ensure that mod_include is loaded
1258 <IfModule !include_module>
1259 Error "mod_include is required by mod_foo. Load it with LoadModule."
1262 # ensure that exactly one of SSL,NOSSL is defined
1263 <IfDefine SSL>
1264 <IfDefine NOSSL>
1265 Error "Both SSL and NOSSL are defined. Define only one of them."
1268 <IfDefine !SSL>
1269 <IfDefine !NOSSL>
1270 Error "Either SSL or NOSSL must be defined."
1272 </IfDefine></pre>
1277 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1278 <div class="directive-section"><h2><a name="ErrorDocument" id="ErrorDocument">ErrorDocument</a> <a name="errordocument" id="errordocument">Directive</a></h2>
1279 <table class="directive">
1280 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>What the server will return to the client
1281 in case of an error</td></tr>
1282 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ErrorDocument <var>error-code</var> <var>document</var></code></td></tr>
1283 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1284 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1285 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1286 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1288 <p>In the event of a problem or error, Apache httpd can be configured
1289 to do one of four things,</p>
1292 <li>output a simple hardcoded error message</li>
1294 <li>output a customized message</li>
1296 <li>internally redirect to a local <var>URL-path</var> to handle the
1299 <li>redirect to an external <var>URL</var> to handle the
1303 <p>The first option is the default, while options 2-4 are
1304 configured using the <code class="directive">ErrorDocument</code>
1305 directive, which is followed by the HTTP response code and a URL
1306 or a message. Apache httpd will sometimes offer additional information
1307 regarding the problem/error.</p>
1309 <p>URLs can begin with a slash (/) for local web-paths (relative
1310 to the <code class="directive"><a href="#documentroot">DocumentRoot</a></code>), or be a
1311 full URL which the client can resolve. Alternatively, a message
1312 can be provided to be displayed by the browser. Examples:</p>
1314 <pre class="prettyprint lang-config">ErrorDocument 500 http://foo.example.com/cgi-bin/tester
1315 ErrorDocument 404 /cgi-bin/bad_urls.pl
1316 ErrorDocument 401 /subscription_info.html
1317 ErrorDocument 403 "Sorry can't allow you access today"
1318 ErrorDocument 403 Forbidden!</pre>
1321 <p>Additionally, the special value <code>default</code> can be used
1322 to specify Apache httpd's simple hardcoded message. While not required
1323 under normal circumstances, <code>default</code> will restore
1324 Apache httpd's simple hardcoded message for configurations that would
1325 otherwise inherit an existing <code class="directive">ErrorDocument</code>.</p>
1327 <pre class="prettyprint lang-config">ErrorDocument 404 /cgi-bin/bad_urls.pl
1329 <Directory /web/docs>
1330 ErrorDocument 404 default
1331 </Directory></pre>
1334 <p>Note that when you specify an <code class="directive">ErrorDocument</code>
1335 that points to a remote URL (ie. anything with a method such as
1336 <code>http</code> in front of it), Apache HTTP Server will send a redirect to the
1337 client to tell it where to find the document, even if the
1338 document ends up being on the same server. This has several
1339 implications, the most important being that the client will not
1340 receive the original error status code, but instead will
1341 receive a redirect status code. This in turn can confuse web
1342 robots and other clients which try to determine if a URL is
1343 valid using the status code. In addition, if you use a remote
1344 URL in an <code>ErrorDocument 401</code>, the client will not
1345 know to prompt the user for a password since it will not
1346 receive the 401 status code. Therefore, <strong>if you use an
1347 <code>ErrorDocument 401</code> directive then it must refer to a local
1348 document.</strong></p>
1350 <p>Microsoft Internet Explorer (MSIE) will by default ignore
1351 server-generated error messages when they are "too small" and substitute
1352 its own "friendly" error messages. The size threshold varies depending on
1353 the type of error, but in general, if you make your error document
1354 greater than 512 bytes, then MSIE will show the server-generated
1355 error rather than masking it. More information is available in
1356 Microsoft Knowledge Base article <a href="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q294807">Q294807</a>.</p>
1358 <p>Although most error messages can be overridden, there are certain
1359 circumstances where the internal messages are used regardless of the
1360 setting of <code class="directive"><a href="#errordocument">ErrorDocument</a></code>. In
1361 particular, if a malformed request is detected, normal request processing
1362 will be immediately halted and the internal error message returned.
1363 This is necessary to guard against security problems caused by
1366 <p>If you are using mod_proxy, you may wish to enable
1367 <code class="directive"><a href="../mod/mod_proxy.html#proxyerroroverride">ProxyErrorOverride</a></code> so that you can provide
1368 custom error messages on behalf of your Origin servers. If you don't enable ProxyErrorOverride,
1369 Apache httpd will not generate custom error documents for proxied content.</p>
1373 <li><a href="../custom-error.html">documentation of
1374 customizable responses</a></li>
1377 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1378 <div class="directive-section"><h2><a name="ErrorLog" id="ErrorLog">ErrorLog</a> <a name="errorlog" id="errorlog">Directive</a></h2>
1379 <table class="directive">
1380 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Location where the server will log errors</td></tr>
1381 <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>
1382 <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>
1383 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1384 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1385 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1387 <p>The <code class="directive">ErrorLog</code> directive sets the name of
1388 the file to which the server will log any errors it encounters. If
1389 the <var>file-path</var> is not absolute then it is assumed to be
1390 relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1392 <pre class="prettyprint lang-config">ErrorLog "/var/log/httpd/error_log"</pre>
1395 <p>If the <var>file-path</var>
1396 begins with a pipe character "<code>|</code>" then it is assumed to be a
1397 command to spawn to handle the error log.</p>
1399 <pre class="prettyprint lang-config">ErrorLog "|/usr/local/bin/httpd_errors"</pre>
1402 <p>See the notes on <a href="../logs.html#piped">piped logs</a> for
1403 more information.</p>
1405 <p>Using <code>syslog</code> instead of a filename enables logging
1406 via syslogd(8) if the system supports it and if <code class="module"><a href="../mod/mod_syslog.html">mod_syslog</a></code>
1407 is loaded. The default is to use syslog facility <code>local7</code>,
1408 but you can override this by using the <code>syslog:<var>facility</var></code>
1409 syntax where <var>facility</var> can be one of the names usually documented in
1410 syslog(1). The facility is effectively global, and if it is changed
1411 in individual virtual hosts, the final facility specified affects the
1414 <pre class="prettyprint lang-config">ErrorLog syslog:user</pre>
1417 <p>Additional modules can provide their own ErrorLog providers. The syntax
1418 is similar to <code>syslog</code> example above.</p>
1420 <p>SECURITY: See the <a href="../misc/security_tips.html#serverroot">security tips</a>
1421 document for details on why your security could be compromised
1422 if the directory where log files are stored is writable by
1423 anyone other than the user that starts the server.</p>
1424 <div class="warning"><h3>Note</h3>
1425 <p>When entering a file path on non-Unix platforms, care should be taken
1426 to make sure that only forward slashes are used even though the platform
1427 may allow the use of back slashes. In general it is a good idea to always
1428 use forward slashes throughout the configuration files.</p>
1433 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1434 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1437 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1438 <div class="directive-section"><h2><a name="ErrorLogFormat" id="ErrorLogFormat">ErrorLogFormat</a> <a name="errorlogformat" id="errorlogformat">Directive</a></h2>
1439 <table class="directive">
1440 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Format specification for error log entries</td></tr>
1441 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code> ErrorLogFormat [connection|request] <var>format</var></code></td></tr>
1442 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1443 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1444 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1446 <p><code class="directive">ErrorLogFormat</code> allows to specify what
1447 supplementary information is logged in the error log in addition to the
1448 actual log message.</p>
1450 <pre class="prettyprint lang-config">#Simple example
1451 ErrorLogFormat "[%t] [%l] [pid %P] %F: %E: [client %a] %M"</pre>
1454 <p>Specifying <code>connection</code> or <code>request</code> as first
1455 parameter allows to specify additional formats, causing additional
1456 information to be logged when the first message is logged for a specific
1457 connection or request, respectively. This additional information is only
1458 logged once per connection/request. If a connection or request is processed
1459 without causing any log message, the additional information is not logged
1462 <p>It can happen that some format string items do not produce output. For
1463 example, the Referer header is only present if the log message is
1464 associated to a request and the log message happens at a time when the
1465 Referer header has already been read from the client. If no output is
1466 produced, the default behavior is to delete everything from the preceding
1467 space character to the next space character. This means the log line is
1468 implicitly divided into fields on non-whitespace to whitespace transitions.
1469 If a format string item does not produce output, the whole field is
1470 omitted. For example, if the remote address <code>%a</code> in the log
1471 format <code>[%t] [%l] [%a] %M </code> is not available, the surrounding
1472 brackets are not logged either. Space characters can be escaped with a
1473 backslash to prevent them from delimiting a field. The combination '% '
1474 (percent space) is a zero-width field delimiter that does not produce any
1477 <p>The above behavior can be changed by adding modifiers to the format
1478 string item. A <code>-</code> (minus) modifier causes a minus to be logged if the
1479 respective item does not produce any output. In once-per-connection/request
1480 formats, it is also possible to use the <code>+</code> (plus) modifier. If an
1481 item with the plus modifier does not produce any output, the whole line is
1484 <p>A number as modifier can be used to assign a log severity level to a
1485 format item. The item will only be logged if the severity of the log
1486 message is not higher than the specified log severity level. The number can
1487 range from 1 (alert) over 4 (warn) and 7 (debug) to 15 (trace8).</p>
1489 <p>For example, here's what would happen if you added modifiers to
1490 the <code>%{Referer}i</code> token, which logs the
1491 <code>Referer</code> request header.</p>
1493 <table class="bordered"><tr class="header"><th>Modified Token</th><th>Meaning</th></tr>
1495 <td><code>%-{Referer}i</code></td>
1496 <td>Logs a <code>-</code> if <code>Referer</code> is not set.</td>
1499 <td><code>%+{Referer}i</code></td>
1500 <td>Omits the entire line if <code>Referer</code> is not set.</td>
1503 <td><code>%4{Referer}i</code></td>
1504 <td>Logs the <code>Referer</code> only if the log message severity
1505 is higher than 4.</td>
1509 <p>Some format string items accept additional parameters in braces.</p>
1511 <table class="bordered"><tr class="header"><th>Format String</th> <th>Description</th></tr>
1512 <tr><td><code>%%</code></td>
1513 <td>The percent sign</td></tr>
1514 <tr class="odd"><td><code>%a</code></td>
1515 <td>Client IP address and port of the request</td></tr>
1516 <tr><td><code>%{c}a</code></td>
1517 <td>Underlying peer IP address and port of the connection (see the
1518 <code class="module"><a href="../mod/mod_remoteip.html">mod_remoteip</a></code> module)</td></tr>
1519 <tr class="odd"><td><code>%A</code></td>
1520 <td>Local IP-address and port</td></tr>
1521 <tr><td><code>%{<em>name</em>}e</code></td>
1522 <td>Request environment variable <em>name</em></td></tr>
1523 <tr class="odd"><td><code>%E</code></td>
1524 <td>APR/OS error status code and string</td></tr>
1525 <tr><td><code>%F</code></td>
1526 <td>Source file name and line number of the log call</td></tr>
1527 <tr class="odd"><td><code>%{<em>name</em>}i</code></td>
1528 <td>Request header <em>name</em></td></tr>
1529 <tr><td><code>%k</code></td>
1530 <td>Number of keep-alive requests on this connection</td></tr>
1531 <tr class="odd"><td><code>%l</code></td>
1532 <td>Loglevel of the message</td></tr>
1533 <tr><td><code>%L</code></td>
1534 <td>Log ID of the request</td></tr>
1535 <tr class="odd"><td><code>%{c}L</code></td>
1536 <td>Log ID of the connection</td></tr>
1537 <tr><td><code>%{C}L</code></td>
1538 <td>Log ID of the connection if used in connection scope, empty otherwise</td></tr>
1539 <tr class="odd"><td><code>%m</code></td>
1540 <td>Name of the module logging the message</td></tr>
1541 <tr><td><code>%M</code></td>
1542 <td>The actual log message</td></tr>
1543 <tr class="odd"><td><code>%{<em>name</em>}n</code></td>
1544 <td>Request note <em>name</em></td></tr>
1545 <tr><td><code>%P</code></td>
1546 <td>Process ID of current process</td></tr>
1547 <tr class="odd"><td><code>%T</code></td>
1548 <td>Thread ID of current thread</td></tr>
1549 <tr><td><code>%{g}T</code></td>
1550 <td>System unique thread ID of current thread (the same ID as
1551 displayed by e.g. <code>top</code>; currently Linux only)</td></tr>
1552 <tr class="odd"><td><code>%t</code></td>
1553 <td>The current time</td></tr>
1554 <tr><td><code>%{u}t</code></td>
1555 <td>The current time including micro-seconds</td></tr>
1556 <tr class="odd"><td><code>%{cu}t</code></td>
1557 <td>The current time in compact ISO 8601 format, including
1558 micro-seconds</td></tr>
1559 <tr><td><code>%v</code></td>
1560 <td>The canonical <code class="directive"><a href="#servername">ServerName</a></code>
1561 of the current server.</td></tr>
1562 <tr class="odd"><td><code>%V</code></td>
1563 <td>The server name of the server serving the request according to the
1564 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code>
1566 <tr><td><code>\ </code> (backslash space)</td>
1567 <td>Non-field delimiting space</td></tr>
1568 <tr class="odd"><td><code>% </code> (percent space)</td>
1569 <td>Field delimiter (no output)</td></tr>
1572 <p>The log ID format <code>%L</code> produces a unique id for a connection
1573 or request. This can be used to correlate which log lines belong to the
1574 same connection or request, which request happens on which connection.
1575 A <code>%L</code> format string is also available in
1576 <code class="module"><a href="../mod/mod_log_config.html">mod_log_config</a></code>, to allow to correlate access log entries
1577 with error log lines. If <code class="module"><a href="../mod/mod_unique_id.html">mod_unique_id</a></code> is loaded, its
1578 unique id will be used as log ID for requests.</p>
1580 <pre class="prettyprint lang-config">#Example (default format for threaded MPMs)
1581 ErrorLogFormat "[%{u}t] [%-m:%l] [pid %P:tid %T] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"</pre>
1584 <p>This would result in error messages such as:</p>
1586 <div class="example"><p><code>
1587 [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
1590 <p>Notice that, as discussed above, some fields are omitted
1591 entirely because they are not defined.</p>
1593 <pre class="prettyprint lang-config">#Example (similar to the 2.2.x format)
1594 ErrorLogFormat "[%t] [%l] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"</pre>
1597 <pre class="prettyprint lang-config">#Advanced example with request/connection log IDs
1598 ErrorLogFormat "[%{uc}t] [%-m:%-l] [R:%L] [C:%{C}L] %7F: %E: %M"
1599 ErrorLogFormat request "[%{uc}t] [R:%L] Request %k on C:%{c}L pid:%P tid:%T"
1600 ErrorLogFormat request "[%{uc}t] [R:%L] UA:'%+{User-Agent}i'"
1601 ErrorLogFormat request "[%{uc}t] [R:%L] Referer:'%+{Referer}i'"
1602 ErrorLogFormat connection "[%{uc}t] [C:%{c}L] local\ %a remote\ %A"</pre>
1608 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
1609 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1610 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1613 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1614 <div class="directive-section"><h2><a name="ExtendedStatus" id="ExtendedStatus">ExtendedStatus</a> <a name="extendedstatus" id="extendedstatus">Directive</a></h2>
1615 <table class="directive">
1616 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Keep track of extended status information for each
1618 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ExtendedStatus On|Off</code></td></tr>
1619 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ExtendedStatus Off[*]</code></td></tr>
1620 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
1621 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1622 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1624 <p>This option tracks additional data per worker about the
1625 currently executing request, and a utilization summary; you
1626 can see these variables during runtime by configuring
1627 <code class="module"><a href="../mod/mod_status.html">mod_status</a></code>. Note that other modules may
1628 rely on this scoreboard.</p>
1630 <p>This setting applies to the entire server, and cannot be
1631 enabled or disabled on a virtualhost-by-virtualhost basis.
1632 The collection of extended status information can slow down
1633 the server. Also note that this setting cannot be changed
1634 during a graceful restart.</p>
1637 <p>Note that loading <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> will change
1638 the default behavior to ExtendedStatus On, while other
1639 third party modules may do the same. Such modules rely on
1640 collecting detailed information about the state of all workers.
1641 The default is changed by <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> beginning
1642 with version 2.3.6; the previous default was always Off.</p>
1647 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1648 <div class="directive-section"><h2><a name="FileETag" id="FileETag">FileETag</a> <a name="fileetag" id="fileetag">Directive</a></h2>
1649 <table class="directive">
1650 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>File attributes used to create the ETag
1651 HTTP response header for static files</td></tr>
1652 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>FileETag <var>component</var> ...</code></td></tr>
1653 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>FileETag MTime Size</code></td></tr>
1654 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1655 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1656 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1657 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1658 <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
1662 The <code class="directive">FileETag</code> directive configures the file
1663 attributes that are used to create the <code>ETag</code> (entity
1664 tag) response header field when the document is based on a static file.
1665 (The <code>ETag</code> value is used in cache management to save
1666 network bandwidth.) The
1667 <code class="directive">FileETag</code> directive allows you to choose
1668 which of these -- if any -- should be used. The recognized keywords are:
1672 <dt><strong>INode</strong></dt>
1673 <dd>The file's i-node number will be included in the calculation</dd>
1674 <dt><strong>MTime</strong></dt>
1675 <dd>The date and time the file was last modified will be included</dd>
1676 <dt><strong>Size</strong></dt>
1677 <dd>The number of bytes in the file will be included</dd>
1678 <dt><strong>All</strong></dt>
1679 <dd>All available fields will be used. This is equivalent to:
1680 <pre class="prettyprint lang-config">FileETag INode MTime Size</pre>
1682 <dt><strong>None</strong></dt>
1683 <dd>If a document is file-based, no <code>ETag</code> field will be
1684 included in the response</dd>
1687 <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
1688 keywords may be prefixed with either <code>+</code> or <code>-</code>,
1689 which allow changes to be made to the default setting inherited
1690 from a broader scope. Any keyword appearing without such a prefix
1691 immediately and completely cancels the inherited setting.</p>
1693 <p>If a directory's configuration includes
1694 <code>FileETag INode MTime Size</code>, and a
1695 subdirectory's includes <code>FileETag -INode</code>,
1696 the setting for that subdirectory (which will be inherited by
1697 any sub-subdirectories that don't override it) will be equivalent to
1698 <code>FileETag MTime Size</code>.</p>
1699 <div class="warning"><h3>Warning</h3>
1700 Do not change the default for directories or locations that have WebDAV
1701 enabled and use <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> as a storage provider.
1702 <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> uses <code>MTime Size</code>
1703 as a fixed format for <code>ETag</code> comparisons on conditional requests.
1704 These conditional requests will break if the <code>ETag</code> format is
1705 changed via <code class="directive">FileETag</code>.
1707 <div class="note"><h3>Server Side Includes</h3>
1708 An ETag is not generated for responses parsed by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>,
1709 since the response entity can change without a change of the INode, MTime, or Size
1710 of the static file with embedded SSI directives.
1715 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1716 <div class="directive-section"><h2><a name="Files" id="Files"><Files></a> <a name="files" id="files">Directive</a></h2>
1717 <table class="directive">
1718 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to matched
1720 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Files <var>filename</var>> ... </Files></code></td></tr>
1721 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1722 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1723 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1724 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1726 <p>The <code class="directive"><Files></code> directive
1727 limits the scope of the enclosed directives by filename. It is comparable
1728 to the <code class="directive"><a href="#directory"><Directory></a></code>
1729 and <code class="directive"><a href="#location"><Location></a></code>
1730 directives. It should be matched with a <code></Files></code>
1731 directive. The directives given within this section will be applied to
1732 any object with a basename (last component of filename) matching the
1733 specified filename. <code class="directive"><Files></code>
1734 sections are processed in the order they appear in the
1735 configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
1736 <code>.htaccess</code> files are read, but before <code class="directive"><a href="#location"><Location></a></code> sections. Note
1737 that <code class="directive"><Files></code> can be nested
1738 inside <code class="directive"><a href="#directory"><Directory></a></code> sections to restrict the
1739 portion of the filesystem they apply to.</p>
1741 <p>The <var>filename</var> argument should include a filename, or
1742 a wild-card string, where <code>?</code> matches any single character,
1743 and <code>*</code> matches any sequences of characters.</p>
1744 <pre class="prettyprint lang-config"><Files "cat.html">
1745 # Insert stuff that applies to cat.html here
1748 <Files "?at.*">
1749 # This would apply to cat.html, bat.html, hat.php and so on.
1750 </Files></pre>
1752 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
1753 can also be used, with the addition of the
1754 <code>~</code> character. For example:</p>
1756 <pre class="prettyprint lang-config"><Files ~ "\.(gif|jpe?g|png)$">
1758 </Files></pre>
1761 <p>would match most common Internet graphics formats. <code class="directive"><a href="#filesmatch"><FilesMatch></a></code> is preferred,
1764 <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
1765 <code>.htaccess</code> files. This allows users to control access to
1766 their own files, at a file-by-file level.</p>
1771 <li><a href="../sections.html">How <Directory>, <Location>
1772 and <Files> sections work</a> for an explanation of how these
1773 different sections are combined when a request is received</li>
1776 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1777 <div class="directive-section"><h2><a name="FilesMatch" id="FilesMatch"><FilesMatch></a> <a name="filesmatch" id="filesmatch">Directive</a></h2>
1778 <table class="directive">
1779 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to regular-expression matched
1781 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><FilesMatch <var>regex</var>> ... </FilesMatch></code></td></tr>
1782 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1783 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1784 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1785 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1787 <p>The <code class="directive"><FilesMatch></code> directive
1788 limits the scope of the enclosed directives by filename, just as the
1789 <code class="directive"><a href="#files"><Files></a></code> directive
1790 does. However, it accepts a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular
1791 expression</a>. For example:</p>
1793 <pre class="prettyprint lang-config"><FilesMatch "\.(gif|jpe?g|png)$">
1795 </FilesMatch></pre>
1798 <p>would match most common Internet graphics formats.</p>
1800 <p>From 2.4.8 onwards, named groups and backreferences are captured and
1801 written to the environment with the corresponding name prefixed with
1802 "MATCH_" and in upper case. This allows elements of files to be referenced
1803 from within <a href="../expr.html">expressions</a> and modules like
1804 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
1805 (unnamed) backreferences are ignored. Use named groups instead.</p>
1807 <pre class="prettyprint lang-config"><FilesMatch ^(?<sitename>[^/]+)>
1808 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
1809 </FilesMatch></pre>
1814 <li><a href="../sections.html">How <Directory>, <Location>
1815 and <Files> sections work</a> for an explanation of how these
1816 different sections are combined when a request is received</li>
1819 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1820 <div class="directive-section"><h2><a name="ForceType" id="ForceType">ForceType</a> <a name="forcetype" id="forcetype">Directive</a></h2>
1821 <table class="directive">
1822 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be served with the specified
1823 media type in the HTTP Content-Type header field</td></tr>
1824 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ForceType <var>media-type</var>|None</code></td></tr>
1825 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
1826 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1827 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1828 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1830 <p>When placed into an <code>.htaccess</code> file or a
1831 <code class="directive"><a href="#directory"><Directory></a></code>, or
1832 <code class="directive"><a href="#location"><Location></a></code> or
1833 <code class="directive"><a href="#files"><Files></a></code>
1834 section, this directive forces all matching files to be served
1835 with the content type identification given by
1836 <var>media-type</var>. For example, if you had a directory full of
1837 GIF files, but did not want to label them all with <code>.gif</code>,
1838 you might want to use:</p>
1840 <pre class="prettyprint lang-config">ForceType image/gif</pre>
1843 <p>Note that this directive overrides other indirect media type
1844 associations defined in mime.types or via the
1845 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code>.</p>
1847 <p>You can also override more general
1848 <code class="directive">ForceType</code> settings
1849 by using the value of <code>None</code>:</p>
1851 <pre class="prettyprint lang-config"># force all files to be image/gif:
1852 <Location /images>
1856 # but normal mime-type associations here:
1857 <Location /images/mixed>
1859 </Location></pre>
1862 <p>This directive primarily overrides the content types generated for
1863 static files served out of the filesystem. For resources other than
1864 static files, where the generator of the response typically specifies
1865 a Content-Type, this directive has no effect.</p>
1869 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1870 <div class="directive-section"><h2><a name="GprofDir" id="GprofDir">GprofDir</a> <a name="gprofdir" id="gprofdir">Directive</a></h2>
1871 <table class="directive">
1872 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory to write gmon.out profiling data to. </td></tr>
1873 <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>
1874 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1875 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1876 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1878 <p>When the server has been compiled with gprof profiling support,
1879 <code class="directive">GprofDir</code> causes <code>gmon.out</code> files to
1880 be written to the specified directory when the process exits. If the
1881 argument ends with a percent symbol ('%'), subdirectories are created
1882 for each process id.</p>
1884 <p>This directive currently only works with the <code class="module"><a href="../mod/prefork.html">prefork</a></code>
1888 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1889 <div class="directive-section"><h2><a name="HostnameLookups" id="HostnameLookups">HostnameLookups</a> <a name="hostnamelookups" id="hostnamelookups">Directive</a></h2>
1890 <table class="directive">
1891 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables DNS lookups on client IP addresses</td></tr>
1892 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>HostnameLookups On|Off|Double</code></td></tr>
1893 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>HostnameLookups Off</code></td></tr>
1894 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1895 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1896 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1898 <p>This directive enables DNS lookups so that host names can be
1899 logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
1900 The value <code>Double</code> refers to doing double-reverse
1901 DNS lookup. That is, after a reverse lookup is performed, a forward
1902 lookup is then performed on that result. At least one of the IP
1903 addresses in the forward lookup must match the original
1904 address. (In "tcpwrappers" terminology this is called
1905 <code>PARANOID</code>.)</p>
1907 <p>Regardless of the setting, when <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code> is
1908 used for controlling access by hostname, a double reverse lookup
1909 will be performed. This is necessary for security. Note that the
1910 result of this double-reverse isn't generally available unless you
1911 set <code>HostnameLookups Double</code>. For example, if only
1912 <code>HostnameLookups On</code> and a request is made to an object
1913 that is protected by hostname restrictions, regardless of whether
1914 the double-reverse fails or not, CGIs will still be passed the
1915 single-reverse result in <code>REMOTE_HOST</code>.</p>
1917 <p>The default is <code>Off</code> in order to save the network
1918 traffic for those sites that don't truly need the reverse
1919 lookups done. It is also better for the end users because they
1920 don't have to suffer the extra latency that a lookup entails.
1921 Heavily loaded sites should leave this directive
1922 <code>Off</code>, since DNS lookups can take considerable
1923 amounts of time. The utility <code class="program"><a href="../programs/logresolve.html">logresolve</a></code>, compiled by
1924 default to the <code>bin</code> subdirectory of your installation
1925 directory, can be used to look up host names from logged IP addresses
1928 <p>Finally, if you have <a href="mod_authz_host.html#reqhost">hostname-based Require
1929 directives</a>, a hostname lookup will be performed regardless of
1930 the setting of <code>HostnameLookups</code>.</p>
1933 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1934 <div class="directive-section"><h2><a name="If" id="If"><If></a> <a name="if" id="if">Directive</a></h2>
1935 <table class="directive">
1936 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is
1937 satisfied by a request at runtime</td></tr>
1938 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><If <var>expression</var>> ... </If></code></td></tr>
1939 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1940 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1941 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1942 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1944 <p>The <code class="directive"><If></code> directive
1945 evaluates an expression at runtime, and applies the enclosed
1946 directives if and only if the expression evaluates to true.
1949 <pre class="prettyprint lang-config"><If "-z req('Host')"></pre>
1952 <p>would match HTTP/1.0 requests without a <var>Host:</var> header.
1953 Expressions may contain various shell-like operators for string
1954 comparison (<code>==</code>, <code>!=</code>, <code><</code>, ...),
1955 integer comparison (<code>-eq</code>, <code>-ne</code>, ...),
1956 and others (<code>-n</code>, <code>-z</code>, <code>-f</code>, ...).
1957 It is also possible to use regular expressions, </p>
1959 <pre class="prettyprint lang-config"><If "%{QUERY_STRING} =~ /(delete|commit)=.*?elem/"></pre>
1962 <p>shell-like pattern matches and many other operations. These operations
1963 can be done on request headers (<code>req</code>), environment variables
1964 (<code>env</code>), and a large number of other properties. The full
1965 documentation is available in <a href="../expr.html">Expressions in
1966 Apache HTTP Server</a>.</p>
1968 <p>Only directives that support the <a href="directive-dict.html#Context">directory context</a> can be used within this configuration section.</p>
1973 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
1974 for a complete reference and more examples.</li>
1975 <li><code class="directive"><a href="#elseif"><ElseIf></a></code></li>
1976 <li><code class="directive"><a href="#else"><Else></a></code></li>
1977 <li><a href="../sections.html">How <Directory>, <Location>,
1978 <Files> sections work</a> for an explanation of how these
1979 different sections are combined when a request is received.
1980 <code class="directive"><If></code>,
1981 <code class="directive"><ElseIf></code>, and
1982 <code class="directive"><Else></code> are applied last.</li>
1985 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1986 <div class="directive-section"><h2><a name="IfDefine" id="IfDefine"><IfDefine></a> <a name="ifdefine" id="ifdefine">Directive</a></h2>
1987 <table class="directive">
1988 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that will be processed only
1989 if a test is true at startup</td></tr>
1990 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfDefine [!]<var>parameter-name</var>> ...
1991 </IfDefine></code></td></tr>
1992 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1993 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1994 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1995 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1997 <p>The <code><IfDefine <var>test</var>>...</IfDefine>
1998 </code> section is used to mark directives that are conditional. The
1999 directives within an <code class="directive"><IfDefine></code>
2000 section are only processed if the <var>test</var> is true. If <var>
2001 test</var> is false, everything between the start and end markers is
2004 <p>The <var>test</var> in the <code class="directive"><IfDefine></code> section directive can be one of two forms:</p>
2007 <li><var>parameter-name</var></li>
2009 <li><code>!</code><var>parameter-name</var></li>
2012 <p>In the former case, the directives between the start and end
2013 markers are only processed if the parameter named
2014 <var>parameter-name</var> is defined. The second format reverses
2015 the test, and only processes the directives if
2016 <var>parameter-name</var> is <strong>not</strong> defined.</p>
2018 <p>The <var>parameter-name</var> argument is a define as given on the
2019 <code class="program"><a href="../programs/httpd.html">httpd</a></code> command line via <code>-D<var>parameter</var>
2020 </code> at the time the server was started or by the <code class="directive"><a href="#define">Define</a></code> directive.</p>
2022 <p><code class="directive"><IfDefine></code> sections are
2023 nest-able, which can be used to implement simple
2024 multiple-parameter tests. Example:</p>
2026 <div class="example"><p><code>httpd -DReverseProxy -DUseCache -DMemCache ...</code></p></div>
2027 <pre class="prettyprint lang-config"><IfDefine ReverseProxy>
2028 LoadModule proxy_module modules/mod_proxy.so
2029 LoadModule proxy_http_module modules/mod_proxy_http.so
2030 <IfDefine UseCache>
2031 LoadModule cache_module modules/mod_cache.so
2032 <IfDefine MemCache>
2033 LoadModule mem_cache_module modules/mod_mem_cache.so
2035 <IfDefine !MemCache>
2036 LoadModule cache_disk_module modules/mod_cache_disk.so
2039 </IfDefine></pre>
2043 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2044 <div class="directive-section"><h2><a name="IfModule" id="IfModule"><IfModule></a> <a name="ifmodule" id="ifmodule">Directive</a></h2>
2045 <table class="directive">
2046 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that are processed conditional on the
2047 presence or absence of a specific module</td></tr>
2048 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfModule [!]<var>module-file</var>|<var>module-identifier</var>> ...
2049 </IfModule></code></td></tr>
2050 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2051 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2052 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2053 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2055 <p>The <code><IfModule <var>test</var>>...</IfModule></code>
2056 section is used to mark directives that are conditional on the presence of
2057 a specific module. The directives within an <code class="directive"><IfModule></code> section are only processed if the <var>test</var>
2058 is true. If <var>test</var> is false, everything between the start and
2059 end markers is ignored.</p>
2061 <p>The <var>test</var> in the <code class="directive"><IfModule></code> section directive can be one of two forms:</p>
2064 <li><var>module</var></li>
2066 <li>!<var>module</var></li>
2069 <p>In the former case, the directives between the start and end
2070 markers are only processed if the module named <var>module</var>
2071 is included in Apache httpd -- either compiled in or
2072 dynamically loaded using <code class="directive"><a href="../mod/mod_so.html#loadmodule">LoadModule</a></code>. The second format reverses the test,
2073 and only processes the directives if <var>module</var> is
2074 <strong>not</strong> included.</p>
2076 <p>The <var>module</var> argument can be either the module identifier or
2077 the file name of the module, at the time it was compiled. For example,
2078 <code>rewrite_module</code> is the identifier and
2079 <code>mod_rewrite.c</code> is the file name. If a module consists of
2080 several source files, use the name of the file containing the string
2081 <code>STANDARD20_MODULE_STUFF</code>.</p>
2083 <p><code class="directive"><IfModule></code> sections are
2084 nest-able, which can be used to implement simple multiple-module
2087 <div class="note">This section should only be used if you need to have one
2088 configuration file that works whether or not a specific module
2089 is available. In normal operation, directives need not be
2090 placed in <code class="directive"><IfModule></code>
2094 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2095 <div class="directive-section"><h2><a name="Include" id="Include">Include</a> <a name="include" id="include">Directive</a></h2>
2096 <table class="directive">
2097 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2098 the server configuration files</td></tr>
2099 <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>
2100 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2101 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2102 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2103 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Directory
2104 wildcard matching available in 2.3.6 and later</td></tr>
2106 <p>This directive allows inclusion of other configuration files
2107 from within the server configuration files.</p>
2109 <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used
2110 in the filename or directory parts of the path to include several files
2111 at once, in alphabetical order. In addition, if
2112 <code class="directive">Include</code> points to a directory, rather than a file,
2113 Apache httpd will read all files in that directory and any subdirectory.
2114 However, including entire directories is not recommended, because it is
2115 easy to accidentally leave temporary files in a directory that can cause
2116 <code class="program"><a href="../programs/httpd.html">httpd</a></code> to fail. Instead, we encourage you to use the
2117 wildcard syntax shown below, to include files that match a particular
2118 pattern, such as *.conf, for example.</p>
2120 <p>The <code class="directive"><a href="#include">Include</a></code> directive will
2121 <strong>fail with an error</strong> if a wildcard expression does not
2122 match any file. The <code class="directive"><a href="#includeoptional">IncludeOptional</a></code>
2123 directive can be used if non-matching wildcards should be ignored.</p>
2125 <p>The file path specified may be an absolute path, or may be relative
2126 to the <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory.</p>
2130 <pre class="prettyprint lang-config">Include /usr/local/apache2/conf/ssl.conf
2131 Include /usr/local/apache2/conf/vhosts/*.conf</pre>
2134 <p>Or, providing paths relative to your <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory:</p>
2136 <pre class="prettyprint lang-config">Include conf/ssl.conf
2137 Include conf/vhosts/*.conf</pre>
2140 <p>Wildcards may be included in the directory or file portion of the
2141 path. This example will fail if there is no subdirectory in conf/vhosts
2142 that contains at least one *.conf file:</p>
2144 <pre class="prettyprint lang-config">Include conf/vhosts/*/*.conf</pre>
2147 <p>Alternatively, the following command will just be ignored in case of
2148 missing files or directories:</p>
2150 <pre class="prettyprint lang-config">IncludeOptional conf/vhosts/*/*.conf</pre>
2156 <li><code class="directive"><a href="#includeoptional">IncludeOptional</a></code></li>
2157 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2160 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2161 <div class="directive-section"><h2><a name="IncludeOptional" id="IncludeOptional">IncludeOptional</a> <a name="includeoptional" id="includeoptional">Directive</a></h2>
2162 <table class="directive">
2163 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2164 the server configuration files</td></tr>
2165 <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>
2166 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2167 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2168 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2169 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in 2.3.6 and later</td></tr>
2171 <p>This directive allows inclusion of other configuration files
2172 from within the server configuration files. It works identically to the
2173 <code class="directive"><a href="#include">Include</a></code> directive, with the
2174 exception that if wildcards do not match any file or directory, the
2175 <code class="directive"><a href="#includeoptional">IncludeOptional</a></code> directive will be
2176 silently ignored instead of causing an error.</p>
2180 <li><code class="directive"><a href="#include">Include</a></code></li>
2181 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2184 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2185 <div class="directive-section"><h2><a name="KeepAlive" id="KeepAlive">KeepAlive</a> <a name="keepalive" id="keepalive">Directive</a></h2>
2186 <table class="directive">
2187 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables HTTP persistent connections</td></tr>
2188 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAlive On|Off</code></td></tr>
2189 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAlive On</code></td></tr>
2190 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2191 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2192 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2194 <p>The Keep-Alive extension to HTTP/1.0 and the persistent
2195 connection feature of HTTP/1.1 provide long-lived HTTP sessions
2196 which allow multiple requests to be sent over the same TCP
2197 connection. In some cases this has been shown to result in an
2198 almost 50% speedup in latency times for HTML documents with
2199 many images. To enable Keep-Alive connections, set
2200 <code>KeepAlive On</code>.</p>
2202 <p>For HTTP/1.0 clients, Keep-Alive connections will only be
2203 used if they are specifically requested by a client. In
2204 addition, a Keep-Alive connection with an HTTP/1.0 client can
2205 only be used when the length of the content is known in
2206 advance. This implies that dynamic content such as CGI output,
2207 SSI pages, and server-generated directory listings will
2208 generally not use Keep-Alive connections to HTTP/1.0 clients.
2209 For HTTP/1.1 clients, persistent connections are the default
2210 unless otherwise specified. If the client requests it, chunked
2211 encoding will be used in order to send content of unknown
2212 length over persistent connections.</p>
2214 <p>When a client uses a Keep-Alive connection it will be counted
2215 as a single "request" for the <code class="directive"><a href="../mod/mpm_common.html#maxconnectionsperchild">MaxConnectionsPerChild</a></code> directive, regardless
2216 of how many requests are sent using the connection.</p>
2220 <li><code class="directive"><a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></code></li>
2223 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2224 <div class="directive-section"><h2><a name="KeepAliveTimeout" id="KeepAliveTimeout">KeepAliveTimeout</a> <a name="keepalivetimeout" id="keepalivetimeout">Directive</a></h2>
2225 <table class="directive">
2226 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for subsequent
2227 requests on a persistent connection</td></tr>
2228 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAliveTimeout <var>num</var>[ms]</code></td></tr>
2229 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAliveTimeout 5</code></td></tr>
2230 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2231 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2232 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2234 <p>The number of seconds Apache httpd will wait for a subsequent
2235 request before closing the connection. By adding a postfix of ms the
2236 timeout can be also set in milliseconds. Once a request has been
2237 received, the timeout value specified by the
2238 <code class="directive"><a href="#timeout">Timeout</a></code> directive applies.</p>
2240 <p>Setting <code class="directive">KeepAliveTimeout</code> to a high value
2241 may cause performance problems in heavily loaded servers. The
2242 higher the timeout, the more server processes will be kept
2243 occupied waiting on connections with idle clients.</p>
2245 <p>In a name-based virtual host context, the value of the first
2246 defined virtual host best matching the local IP and port will be used.</p>
2249 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2250 <div class="directive-section"><h2><a name="Limit" id="Limit"><Limit></a> <a name="limit" id="limit">Directive</a></h2>
2251 <table class="directive">
2252 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict enclosed access controls to only certain HTTP
2254 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Limit <var>method</var> [<var>method</var>] ... > ...
2255 </Limit></code></td></tr>
2256 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2257 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2258 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2259 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2261 <p>Access controls are normally effective for
2262 <strong>all</strong> access methods, and this is the usual
2263 desired behavior. <strong>In the general case, access control
2264 directives should not be placed within a
2265 <code class="directive"><Limit></code> section.</strong></p>
2267 <p>The purpose of the <code class="directive"><Limit></code>
2268 directive is to restrict the effect of the access controls to the
2269 nominated HTTP methods. For all other methods, the access
2270 restrictions that are enclosed in the <code class="directive"><Limit></code> bracket <strong>will have no
2271 effect</strong>. The following example applies the access control
2272 only to the methods <code>POST</code>, <code>PUT</code>, and
2273 <code>DELETE</code>, leaving all other methods unprotected:</p>
2275 <pre class="prettyprint lang-config"><Limit POST PUT DELETE>
2277 </Limit></pre>
2280 <p>The method names listed can be one or more of: <code>GET</code>,
2281 <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
2282 <code>CONNECT</code>, <code>OPTIONS</code>,
2283 <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
2284 <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
2285 <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
2286 case-sensitive.</strong> If <code>GET</code> is used it will also
2287 restrict <code>HEAD</code> requests. The <code>TRACE</code> method
2288 cannot be limited (see <code class="directive"><a href="#traceenable">TraceEnable</a></code>).</p>
2290 <div class="warning">A <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section should always be
2291 used in preference to a <code class="directive"><Limit></code>
2292 section when restricting access, since a <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section provides protection
2293 against arbitrary methods.</div>
2295 <p>The <code class="directive"><Limit></code> and
2296 <code class="directive"><a href="#limitexcept"><LimitExcept></a></code>
2297 directives may be nested. In this case, each successive level of
2298 <code class="directive"><Limit></code> or <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> directives must
2299 further restrict the set of methods to which access controls apply.</p>
2301 <div class="warning">When using
2302 <code class="directive"><Limit></code> or
2303 <code class="directive"><LimitExcept></code> directives with
2304 the <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directive,
2305 note that the first <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code>
2306 to succeed authorizes the request, regardless of the presence of other
2307 <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directives.</div>
2309 <p>For example, given the following configuration, all users will
2310 be authorized for <code>POST</code> requests, and the
2311 <code>Require group editors</code> directive will be ignored
2314 <pre class="prettyprint lang-config"><LimitExcept GET>
2316 </LimitExcept>
2318 Require group editors
2319 </Limit></pre>
2323 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2324 <div class="directive-section"><h2><a name="LimitExcept" id="LimitExcept"><LimitExcept></a> <a name="limitexcept" id="limitexcept">Directive</a></h2>
2325 <table class="directive">
2326 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict access controls to all HTTP methods
2327 except the named ones</td></tr>
2328 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LimitExcept <var>method</var> [<var>method</var>] ... > ...
2329 </LimitExcept></code></td></tr>
2330 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2331 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2332 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2333 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2335 <p><code class="directive"><LimitExcept></code> and
2336 <code></LimitExcept></code> are used to enclose
2337 a group of access control directives which will then apply to any
2338 HTTP access method <strong>not</strong> listed in the arguments;
2339 i.e., it is the opposite of a <code class="directive"><a href="#limit"><Limit></a></code> section and can be used to control
2340 both standard and nonstandard/unrecognized methods. See the
2341 documentation for <code class="directive"><a href="#limit"><Limit></a></code> for more details.</p>
2345 <pre class="prettyprint lang-config"><LimitExcept POST GET>
2347 </LimitExcept></pre>
2352 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2353 <div class="directive-section"><h2><a name="LimitInternalRecursion" id="LimitInternalRecursion">LimitInternalRecursion</a> <a name="limitinternalrecursion" id="limitinternalrecursion">Directive</a></h2>
2354 <table class="directive">
2355 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine maximum number of internal redirects and nested
2356 subrequests</td></tr>
2357 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitInternalRecursion <var>number</var> [<var>number</var>]</code></td></tr>
2358 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitInternalRecursion 10</code></td></tr>
2359 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2360 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2361 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2363 <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
2364 redirects the original request to a CGI script. A subrequest is Apache httpd's
2365 mechanism to find out what would happen for some URI if it were requested.
2366 For example, <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> uses subrequests to look for the
2367 files listed in the <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
2370 <p><code class="directive">LimitInternalRecursion</code> prevents the server
2371 from crashing when entering an infinite loop of internal redirects or
2372 subrequests. Such loops are usually caused by misconfigurations.</p>
2374 <p>The directive stores two different limits, which are evaluated on
2375 per-request basis. The first <var>number</var> is the maximum number of
2376 internal redirects, that may follow each other. The second <var>number</var>
2377 determines, how deep subrequests may be nested. If you specify only one
2378 <var>number</var>, it will be assigned to both limits.</p>
2380 <pre class="prettyprint lang-config">LimitInternalRecursion 5</pre>
2384 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2385 <div class="directive-section"><h2><a name="LimitRequestBody" id="LimitRequestBody">LimitRequestBody</a> <a name="limitrequestbody" id="limitrequestbody">Directive</a></h2>
2386 <table class="directive">
2387 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restricts the total size of the HTTP request body sent
2388 from the client</td></tr>
2389 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestBody <var>bytes</var></code></td></tr>
2390 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestBody 0</code></td></tr>
2391 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2392 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2393 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2394 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2396 <p>This directive specifies the number of <var>bytes</var> from 0
2397 (meaning unlimited) to 2147483647 (2GB) that are allowed in a
2398 request body. See the note below for the limited applicability
2399 to proxy requests.</p>
2401 <p>The <code class="directive">LimitRequestBody</code> directive allows
2402 the user to set a limit on the allowed size of an HTTP request
2403 message body within the context in which the directive is given
2404 (server, per-directory, per-file or per-location). If the client
2405 request exceeds that limit, the server will return an error
2406 response instead of servicing the request. The size of a normal
2407 request message body will vary greatly depending on the nature of
2408 the resource and the methods allowed on that resource. CGI scripts
2409 typically use the message body for retrieving form information.
2410 Implementations of the <code>PUT</code> method will require
2411 a value at least as large as any representation that the server
2412 wishes to accept for that resource.</p>
2414 <p>This directive gives the server administrator greater
2415 control over abnormal client request behavior, which may be
2416 useful for avoiding some forms of denial-of-service
2419 <p>If, for example, you are permitting file upload to a particular
2420 location, and wish to limit the size of the uploaded file to 100K,
2421 you might use the following directive:</p>
2423 <pre class="prettyprint lang-config">LimitRequestBody 102400</pre>
2426 <div class="note"><p>For a full description of how this directive is interpreted by
2427 proxy requests, see the <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> documentation.</p>
2432 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2433 <div class="directive-section"><h2><a name="LimitRequestFields" id="LimitRequestFields">LimitRequestFields</a> <a name="limitrequestfields" id="limitrequestfields">Directive</a></h2>
2434 <table class="directive">
2435 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of HTTP request header fields that
2436 will be accepted from the client</td></tr>
2437 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFields <var>number</var></code></td></tr>
2438 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFields 100</code></td></tr>
2439 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2440 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2441 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2443 <p><var>Number</var> is an integer from 0 (meaning unlimited) to
2444 32767. The default value is defined by the compile-time
2445 constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
2448 <p>The <code class="directive">LimitRequestFields</code> directive allows
2449 the server administrator to modify the limit on the number of
2450 request header fields allowed in an HTTP request. A server needs
2451 this value to be larger than the number of fields that a normal
2452 client request might include. The number of request header fields
2453 used by a client rarely exceeds 20, but this may vary among
2454 different client implementations, often depending upon the extent
2455 to which a user has configured their browser to support detailed
2456 content negotiation. Optional HTTP extensions are often expressed
2457 using request header fields.</p>
2459 <p>This directive gives the server administrator greater
2460 control over abnormal client request behavior, which may be
2461 useful for avoiding some forms of denial-of-service attacks.
2462 The value should be increased if normal clients see an error
2463 response from the server that indicates too many fields were
2464 sent in the request.</p>
2468 <pre class="prettyprint lang-config">LimitRequestFields 50</pre>
2471 <div class="warning"><h3>Warning</h3>
2472 <p> When name-based virtual hosting is used, the value for this
2473 directive is taken from the default (first-listed) virtual host for the
2474 local IP and port combination.</p>
2479 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2480 <div class="directive-section"><h2><a name="LimitRequestFieldSize" id="LimitRequestFieldSize">LimitRequestFieldSize</a> <a name="limitrequestfieldsize" id="limitrequestfieldsize">Directive</a></h2>
2481 <table class="directive">
2482 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of the HTTP request header allowed from the
2484 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFieldSize <var>bytes</var></code></td></tr>
2485 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFieldSize 8190</code></td></tr>
2486 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2487 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2488 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2490 <p>This directive specifies the number of <var>bytes</var>
2491 that will be allowed in an HTTP request header.</p>
2493 <p>The <code class="directive">LimitRequestFieldSize</code> directive
2494 allows the server administrator to set the limit
2495 on the allowed size of an HTTP request header field. A server
2496 needs this value to be large enough to hold any one header field
2497 from a normal client request. The size of a normal request header
2498 field will vary greatly among different client implementations,
2499 often depending upon the extent to which a user has configured
2500 their browser to support detailed content negotiation. SPNEGO
2501 authentication headers can be up to 12392 bytes.</p>
2503 <p>This directive gives the server administrator greater
2504 control over abnormal client request behavior, which may be
2505 useful for avoiding some forms of denial-of-service attacks.</p>
2509 <pre class="prettyprint lang-config">LimitRequestFieldSize 4094</pre>
2512 <div class="note">Under normal conditions, the value should not be changed from
2515 <div class="warning"><h3>Warning</h3>
2516 <p> When name-based virtual hosting is used, the value for this
2517 directive is taken from the default (first-listed) virtual host best
2518 matching the current IP address and port combination.</p>
2522 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2523 <div class="directive-section"><h2><a name="LimitRequestLine" id="LimitRequestLine">LimitRequestLine</a> <a name="limitrequestline" id="limitrequestline">Directive</a></h2>
2524 <table class="directive">
2525 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limit the size of the HTTP request line that will be accepted
2526 from the client</td></tr>
2527 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestLine <var>bytes</var></code></td></tr>
2528 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestLine 8190</code></td></tr>
2529 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2530 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2531 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2533 <p>This directive sets the number of <var>bytes</var> that will be
2534 allowed on the HTTP request-line.</p>
2536 <p>The <code class="directive">LimitRequestLine</code> directive allows
2537 the server administrator to set the limit on the allowed size
2538 of a client's HTTP request-line. Since the request-line consists of the
2539 HTTP method, URI, and protocol version, the
2540 <code class="directive">LimitRequestLine</code> directive places a
2541 restriction on the length of a request-URI allowed for a request
2542 on the server. A server needs this value to be large enough to
2543 hold any of its resource names, including any information that
2544 might be passed in the query part of a <code>GET</code> request.</p>
2546 <p>This directive gives the server administrator greater
2547 control over abnormal client request behavior, which may be
2548 useful for avoiding some forms of denial-of-service attacks.</p>
2552 <pre class="prettyprint lang-config">LimitRequestLine 4094</pre>
2555 <div class="note">Under normal conditions, the value should not be changed from
2558 <div class="warning"><h3>Warning</h3>
2559 <p> When name-based virtual hosting is used, the value for this
2560 directive is taken from the default (first-listed) virtual host best
2561 matching the current IP address and port combination.</p>
2566 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2567 <div class="directive-section"><h2><a name="LimitXMLRequestBody" id="LimitXMLRequestBody">LimitXMLRequestBody</a> <a name="limitxmlrequestbody" id="limitxmlrequestbody">Directive</a></h2>
2568 <table class="directive">
2569 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of an XML-based request body</td></tr>
2570 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitXMLRequestBody <var>bytes</var></code></td></tr>
2571 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitXMLRequestBody 1000000</code></td></tr>
2572 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2573 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2574 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2575 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2577 <p>Limit (in bytes) on maximum size of an XML-based request
2578 body. A value of <code>0</code> will disable any checking.</p>
2582 <pre class="prettyprint lang-config">LimitXMLRequestBody 0</pre>
2587 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2588 <div class="directive-section"><h2><a name="Location" id="Location"><Location></a> <a name="location" id="location">Directive</a></h2>
2589 <table class="directive">
2590 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to matching
2592 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Location
2593 <var>URL-path</var>|<var>URL</var>> ... </Location></code></td></tr>
2594 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2595 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2596 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2598 <p>The <code class="directive"><Location></code> directive
2599 limits the scope of the enclosed directives by URL. It is similar to the
2600 <code class="directive"><a href="#directory"><Directory></a></code>
2601 directive, and starts a subsection which is terminated with a
2602 <code></Location></code> directive. <code class="directive"><Location></code> sections are processed in the
2603 order they appear in the configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
2604 <code>.htaccess</code> files are read, and after the <code class="directive"><a href="#files"><Files></a></code> sections.</p>
2606 <p><code class="directive"><Location></code> sections operate
2607 completely outside the filesystem. This has several consequences.
2608 Most importantly, <code class="directive"><Location></code>
2609 directives should not be used to control access to filesystem
2610 locations. Since several different URLs may map to the same
2611 filesystem location, such access controls may by circumvented.</p>
2613 <p>The enclosed directives will be applied to the request if the path component
2614 of the URL meets <em>any</em> of the following criteria:
2617 <li>The specified location matches exactly the path component of the URL.
2619 <li>The specified location, which ends in a forward slash, is a prefix
2620 of the path component of the URL (treated as a context root).
2622 <li>The specified location, with the addition of a trailing slash, is a
2623 prefix of the path component of the URL (also treated as a context root).
2627 In the example below, where no trailing slash is used, requests to
2628 /private1, /private1/ and /private1/file.txt will have the enclosed
2629 directives applied, but /private1other would not.
2631 <pre class="prettyprint lang-config"><Location /private1>
2633 </Location></pre>
2636 In the example below, where a trailing slash is used, requests to
2637 /private2/ and /private2/file.txt will have the enclosed
2638 directives applied, but /private2 and /private2other would not.
2640 <pre class="prettyprint lang-config"><Location /private2<em>/</em>>
2642 </Location></pre>
2645 <div class="note"><h3>When to use <code class="directive"><Location></code></h3>
2647 <p>Use <code class="directive"><Location></code> to apply
2648 directives to content that lives outside the filesystem. For
2649 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
2650 <code><Location /></code>, which is an easy way to
2651 apply a configuration to the entire server.</p>
2654 <p>For all origin (non-proxy) requests, the URL to be matched is a
2655 URL-path of the form <code>/path/</code>. <em>No scheme, hostname,
2656 port, or query string may be included.</em> For proxy requests, the
2657 URL to be matched is of the form
2658 <code>scheme://servername/path</code>, and you must include the
2661 <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
2662 any single character, and <code>*</code> matches any sequences of
2663 characters. Neither wildcard character matches a / in the URL-path.</p>
2665 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
2666 can also be used, with the addition of the <code>~</code>
2667 character. For example:</p>
2669 <pre class="prettyprint lang-config"><Location ~ "/(extra|special)/data">
2671 </Location></pre>
2674 <p>would match URLs that contained the substring <code>/extra/data</code>
2675 or <code>/special/data</code>. The directive <code class="directive"><a href="#locationmatch"><LocationMatch></a></code> behaves
2676 identical to the regex version of <code class="directive"><Location></code>, and is preferred, for the
2677 simple reason that <code>~</code> is hard to distinguish from
2678 <code>-</code> in many fonts.</p>
2680 <p>The <code class="directive"><Location></code>
2681 functionality is especially useful when combined with the
2682 <code class="directive"><a href="#sethandler">SetHandler</a></code>
2683 directive. For example, to enable status requests, but allow them
2684 only from browsers at <code>example.com</code>, you might use:</p>
2686 <pre class="prettyprint lang-config"><Location /status>
2687 SetHandler server-status
2688 Require host example.com
2689 </Location></pre>
2692 <div class="note"><h3>Note about / (slash)</h3>
2693 <p>The slash character has special meaning depending on where in a
2694 URL it appears. People may be used to its behavior in the filesystem
2695 where multiple adjacent slashes are frequently collapsed to a single
2696 slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
2697 <code>/home/foo</code>). In URL-space this is not necessarily true.
2698 The <code class="directive"><a href="#locationmatch"><LocationMatch></a></code>
2699 directive and the regex version of <code class="directive"><Location></code> require you to explicitly specify multiple
2700 slashes if that is your intention.</p>
2702 <p>For example, <code><LocationMatch ^/abc></code> would match
2703 the request URL <code>/abc</code> but not the request URL <code>
2704 //abc</code>. The (non-regex) <code class="directive"><Location></code> directive behaves similarly when used for
2705 proxy requests. But when (non-regex) <code class="directive"><Location></code> is used for non-proxy requests it will
2706 implicitly match multiple slashes with a single slash. For example,
2707 if you specify <code><Location /abc/def></code> and the
2708 request is to <code>/abc//def</code> then it will match.</p>
2713 <li><a href="../sections.html">How <Directory>, <Location>
2714 and <Files> sections work</a> for an explanation of how these
2715 different sections are combined when a request is received.</li>
2716 <li><code class="directive"><a href="#locationmatch">LocationMatch</a></code></li>
2719 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2720 <div class="directive-section"><h2><a name="LocationMatch" id="LocationMatch"><LocationMatch></a> <a name="locationmatch" id="locationmatch">Directive</a></h2>
2721 <table class="directive">
2722 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to regular-expression
2723 matching URLs</td></tr>
2724 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LocationMatch
2725 <var>regex</var>> ... </LocationMatch></code></td></tr>
2726 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2727 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2728 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2730 <p>The <code class="directive"><LocationMatch></code> directive
2731 limits the scope of the enclosed directives by URL, in an identical manner
2732 to <code class="directive"><a href="#location"><Location></a></code>. However,
2733 it takes a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
2734 as an argument instead of a simple string. For example:</p>
2736 <pre class="prettyprint lang-config"><LocationMatch "/(extra|special)/data">
2738 </LocationMatch></pre>
2741 <p>would match URLs that contained the substring <code>/extra/data</code>
2742 or <code>/special/data</code>.</p>
2744 <p>From 2.4.8 onwards, named groups and backreferences are captured and
2745 written to the environment with the corresponding name prefixed with
2746 "MATCH_" and in upper case. This allows elements of URLs to be referenced
2747 from within <a href="../expr.html">expressions</a> and modules like
2748 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
2749 (unnamed) backreferences are ignored. Use named groups instead.</p>
2751 <pre class="prettyprint lang-config"><LocationMatch ^/combined/(?<sitename>[^/]+)>
2752 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
2753 </LocationMatch></pre>
2758 <li><a href="../sections.html">How <Directory>, <Location>
2759 and <Files> sections work</a> for an explanation of how these
2760 different sections are combined when a request is received</li>
2763 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2764 <div class="directive-section"><h2><a name="LogLevel" id="LogLevel">LogLevel</a> <a name="loglevel" id="loglevel">Directive</a></h2>
2765 <table class="directive">
2766 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Controls the verbosity of the ErrorLog</td></tr>
2767 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel [<var>module</var>:]<var>level</var>
2768 [<var>module</var>:<var>level</var>] ...
2770 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LogLevel warn</code></td></tr>
2771 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2772 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2773 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2774 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Per-module and per-directory configuration is available in
2775 Apache HTTP Server 2.3.6 and later</td></tr>
2777 <p><code class="directive">LogLevel</code> adjusts the verbosity of the
2778 messages recorded in the error logs (see <code class="directive"><a href="#errorlog">ErrorLog</a></code> directive). The following
2779 <var>level</var>s are available, in order of decreasing
2782 <table class="bordered">
2785 <th><strong>Level</strong> </th>
2787 <th><strong>Description</strong> </th>
2789 <th><strong>Example</strong> </th>
2793 <td><code>emerg</code> </td>
2795 <td>Emergencies - system is unusable.</td>
2797 <td>"Child cannot open lock file. Exiting"</td>
2801 <td><code>alert</code> </td>
2803 <td>Action must be taken immediately.</td>
2805 <td>"getpwuid: couldn't determine user name from uid"</td>
2809 <td><code>crit</code> </td>
2811 <td>Critical Conditions.</td>
2813 <td>"socket: Failed to get a socket, exiting child"</td>
2817 <td><code>error</code> </td>
2819 <td>Error conditions.</td>
2821 <td>"Premature end of script headers"</td>
2825 <td><code>warn</code> </td>
2827 <td>Warning conditions.</td>
2829 <td>"child process 1234 did not exit, sending another
2834 <td><code>notice</code> </td>
2836 <td>Normal but significant condition.</td>
2838 <td>"httpd: caught SIGBUS, attempting to dump core in
2843 <td><code>info</code> </td>
2845 <td>Informational.</td>
2847 <td>"Server seems busy, (you may need to increase
2848 StartServers, or Min/MaxSpareServers)..."</td>
2852 <td><code>debug</code> </td>
2854 <td>Debug-level messages</td>
2856 <td>"Opening config file ..."</td>
2859 <td><code>trace1</code> </td>
2861 <td>Trace messages</td>
2863 <td>"proxy: FTP: control connection complete"</td>
2866 <td><code>trace2</code> </td>
2868 <td>Trace messages</td>
2870 <td>"proxy: CONNECT: sending the CONNECT request to the remote proxy"</td>
2873 <td><code>trace3</code> </td>
2875 <td>Trace messages</td>
2877 <td>"openssl: Handshake: start"</td>
2880 <td><code>trace4</code> </td>
2882 <td>Trace messages</td>
2884 <td>"read from buffered SSL brigade, mode 0, 17 bytes"</td>
2887 <td><code>trace5</code> </td>
2889 <td>Trace messages</td>
2891 <td>"map lookup FAILED: map=rewritemap key=keyname"</td>
2894 <td><code>trace6</code> </td>
2896 <td>Trace messages</td>
2898 <td>"cache lookup FAILED, forcing new map lookup"</td>
2901 <td><code>trace7</code> </td>
2903 <td>Trace messages, dumping large amounts of data</td>
2905 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2908 <td><code>trace8</code> </td>
2910 <td>Trace messages, dumping large amounts of data</td>
2912 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2916 <p>When a particular level is specified, messages from all
2917 other levels of higher significance will be reported as well.
2918 <em>E.g.</em>, when <code>LogLevel info</code> is specified,
2919 then messages with log levels of <code>notice</code> and
2920 <code>warn</code> will also be posted.</p>
2922 <p>Using a level of at least <code>crit</code> is
2927 <pre class="prettyprint lang-config">LogLevel notice</pre>
2930 <div class="note"><h3>Note</h3>
2931 <p>When logging to a regular file messages of the level
2932 <code>notice</code> cannot be suppressed and thus are always
2933 logged. However, this doesn't apply when logging is done
2934 using <code>syslog</code>.</p>
2937 <p>Specifying a level without a module name will reset the level
2938 for all modules to that level. Specifying a level with a module
2939 name will set the level for that module only. It is possible to
2940 use the module source file name, the module identifier, or the
2941 module identifier with the trailing <code>_module</code> omitted
2942 as module specification. This means the following three specifications
2945 <pre class="prettyprint lang-config">LogLevel info ssl:warn
2946 LogLevel info mod_ssl.c:warn
2947 LogLevel info ssl_module:warn</pre>
2950 <p>It is also possible to change the level per directory:</p>
2952 <pre class="prettyprint lang-config">LogLevel info
2953 <Directory "/usr/local/apache/htdocs/app">
2955 </Directory></pre>
2959 Per directory loglevel configuration only affects messages that are
2960 logged after the request has been parsed and that are associated with
2961 the request. Log messages which are associated with the server or
2962 the connection are not affected. The latter can be influenced by the
2963 <code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code> directive,
2969 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
2970 <li><code class="directive"><a href="#errorlogformat">ErrorLogFormat</a></code></li>
2971 <li><code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code></li>
2972 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
2975 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2976 <div class="directive-section"><h2><a name="LogLevelOverride" id="LogLevelOverride">LogLevelOverride</a> <a name="logleveloverride" id="logleveloverride">Directive</a></h2>
2977 <table class="directive">
2978 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Override the verbosity of the ErrorLog for certain clients</td></tr>
2979 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel <var>ipaddress</var>[/<var>prefixlen</var>]
2980 [<var>module</var>:]<var>level</var> [<var>module</var>:<var>level</var>] ...
2982 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>unset</code></td></tr>
2983 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2984 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2985 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2986 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.5.0 and later</td></tr>
2988 <p><code class="directive">LogLevelOverride</code> adjusts the
2989 <code class="directive"><a href="#loglevel">LogLevel</a></code> for requests coming from
2990 certain client IP addresses.
2991 This allows to enable verbose logging only for certain test clients.
2992 The IP address is checked at a very early state in the connection
2993 processing. Therefore, <code class="directive">LogLevelOverride</code> allows to
2994 change the log level for things like the SSL handshake which happen before
2995 a <code class="directive"><a href="#loglevel">LogLevel</a></code> directive in an
2996 <code class="directive"><a href="#if"><If></a></code> container would
2999 <p><code class="directive">LogLevelOverride</code> accepts either a single
3000 IP-address or a CIDR IP-address/len subnet specification.
3001 For the syntax of the loglevel specification, see the
3002 <code class="directive"><a href="#loglevel">LogLevel</a></code> directive.</p>
3004 <p>For requests that match a <code class="directive">LogLevelOverride</code>
3005 directive, per-directory specifications of
3006 <code class="directive"><a href="#loglevel">LogLevel</a></code> are ignored.</p>
3010 <pre class="prettyprint lang-config"> LogLevelOverride 192.0.2.0/24 ssl:trace6
3011 LogLevelOverride 192.0.2.7 ssl:trace8</pre>
3015 <code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code> only affects
3016 log messages that are associated with the request or the connection.
3017 Log messages which are associated with the server not affected.
3023 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
3026 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3027 <div class="directive-section"><h2><a name="MaxKeepAliveRequests" id="MaxKeepAliveRequests">MaxKeepAliveRequests</a> <a name="maxkeepaliverequests" id="maxkeepaliverequests">Directive</a></h2>
3028 <table class="directive">
3029 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of requests allowed on a persistent
3030 connection</td></tr>
3031 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxKeepAliveRequests <var>number</var></code></td></tr>
3032 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxKeepAliveRequests 100</code></td></tr>
3033 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3034 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3035 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3037 <p>The <code class="directive">MaxKeepAliveRequests</code> directive
3038 limits the number of requests allowed per connection when
3039 <code class="directive"><a href="#keepalive">KeepAlive</a></code> is on. If it is
3040 set to <code>0</code>, unlimited requests will be allowed. We
3041 recommend that this setting be kept to a high value for maximum
3042 server performance.</p>
3046 <pre class="prettyprint lang-config">MaxKeepAliveRequests 500</pre>
3050 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3051 <div class="directive-section"><h2><a name="MaxRangeOverlaps" id="MaxRangeOverlaps">MaxRangeOverlaps</a> <a name="maxrangeoverlaps" id="maxrangeoverlaps">Directive</a></h2>
3052 <table class="directive">
3053 <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
3055 <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>
3056 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeOverlaps 20</code></td></tr>
3057 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3058 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3059 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3060 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3062 <p>The <code class="directive">MaxRangeOverlaps</code> directive
3063 limits the number of overlapping HTTP ranges the server is willing to
3064 return to the client. If more overlapping ranges than permitted are requested,
3065 the complete resource is returned instead.</p>
3068 <dt><strong>default</strong></dt>
3069 <dd>Limits the number of overlapping ranges to a compile-time default of 20.</dd>
3071 <dt><strong>none</strong></dt>
3072 <dd>No overlapping Range headers are allowed.</dd>
3074 <dt><strong>unlimited</strong></dt>
3075 <dd>The server does not limit the number of overlapping ranges it is
3076 willing to satisfy.</dd>
3078 <dt><var>number-of-ranges</var></dt>
3079 <dd>A positive number representing the maximum number of overlapping ranges the
3080 server is willing to satisfy.</dd>
3084 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3085 <div class="directive-section"><h2><a name="MaxRangeReversals" id="MaxRangeReversals">MaxRangeReversals</a> <a name="maxrangereversals" id="maxrangereversals">Directive</a></h2>
3086 <table class="directive">
3087 <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
3089 <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>
3090 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeReversals 20</code></td></tr>
3091 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3092 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3093 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3094 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3096 <p>The <code class="directive">MaxRangeReversals</code> directive
3097 limits the number of HTTP Range reversals the server is willing to
3098 return to the client. If more ranges reversals than permitted are requested,
3099 the complete resource is returned instead.</p>
3102 <dt><strong>default</strong></dt>
3103 <dd>Limits the number of range reversals to a compile-time default of 20.</dd>
3105 <dt><strong>none</strong></dt>
3106 <dd>No Range reversals headers are allowed.</dd>
3108 <dt><strong>unlimited</strong></dt>
3109 <dd>The server does not limit the number of range reversals it is
3110 willing to satisfy.</dd>
3112 <dt><var>number-of-ranges</var></dt>
3113 <dd>A positive number representing the maximum number of range reversals the
3114 server is willing to satisfy.</dd>
3118 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3119 <div class="directive-section"><h2><a name="MaxRanges" id="MaxRanges">MaxRanges</a> <a name="maxranges" id="maxranges">Directive</a></h2>
3120 <table class="directive">
3121 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of ranges allowed before returning the complete
3123 <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>
3124 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRanges 200</code></td></tr>
3125 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3126 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3127 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3128 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3130 <p>The <code class="directive">MaxRanges</code> directive
3131 limits the number of HTTP ranges the server is willing to
3132 return to the client. If more ranges than permitted are requested,
3133 the complete resource is returned instead.</p>
3136 <dt><strong>default</strong></dt>
3137 <dd>Limits the number of ranges to a compile-time default of 200.</dd>
3139 <dt><strong>none</strong></dt>
3140 <dd>Range headers are ignored.</dd>
3142 <dt><strong>unlimited</strong></dt>
3143 <dd>The server does not limit the number of ranges it is
3144 willing to satisfy.</dd>
3146 <dt><var>number-of-ranges</var></dt>
3147 <dd>A positive number representing the maximum number of ranges the
3148 server is willing to satisfy.</dd>
3152 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3153 <div class="directive-section"><h2><a name="MergeTrailers" id="MergeTrailers">MergeTrailers</a> <a name="mergetrailers" id="mergetrailers">Directive</a></h2>
3154 <table class="directive">
3155 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determins whether trailers are merged into headers</td></tr>
3156 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MergeTrailers [on|off]</code></td></tr>
3157 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MergeTrailers off</code></td></tr>
3158 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3159 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3160 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3162 <p>This directive controls whether HTTP trailers are copied into the
3163 internal representation of HTTP headers. This mergeing occurs when the
3164 request body has been completely consumed, long after most header
3165 processing would have a chance to examine or modify request headers.</p>
3166 <p>This option is provided for compatibility with releases prior to 2.4.10,
3167 where trailers were always merged.</p>
3170 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3171 <div class="directive-section"><h2><a name="Mutex" id="Mutex">Mutex</a> <a name="mutex" id="mutex">Directive</a></h2>
3172 <table class="directive">
3173 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures mutex mechanism and lock file directory for all
3174 or specified mutexes</td></tr>
3175 <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>
3176 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Mutex default</code></td></tr>
3177 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3178 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3179 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3180 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.4 and later</td></tr>
3182 <p>The <code class="directive">Mutex</code> directive sets the mechanism,
3183 and optionally the lock file location, that httpd and modules use
3184 to serialize access to resources. Specify <code>default</code> as
3185 the first argument to change the settings for all mutexes; specify
3186 a mutex name (see table below) as the first argument to override
3187 defaults only for that mutex.</p>
3189 <p>The <code class="directive">Mutex</code> directive is typically used in
3190 the following exceptional situations:</p>
3193 <li>change the mutex mechanism when the default mechanism selected
3194 by <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> has a functional or performance
3197 <li>change the directory used by file-based mutexes when the
3198 default directory does not support locking</li>
3201 <div class="note"><h3>Supported modules</h3>
3202 <p>This directive only configures mutexes which have been registered
3203 with the core server using the <code>ap_mutex_register()</code> API.
3204 All modules bundled with httpd support the <code class="directive">Mutex</code>
3205 directive, but third-party modules may not. Consult the documentation
3206 of the third-party module, which must indicate the mutex name(s) which
3207 can be configured if this directive is supported.</p>
3210 <p>The following mutex <em>mechanisms</em> are available:</p>
3212 <li><code>default | yes</code>
3213 <p>This selects the default locking implementation, as determined by
3214 <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a>. The default locking implementation can
3215 be displayed by running <code class="program"><a href="../programs/httpd.html">httpd</a></code> with the
3216 <code>-V</code> option.</p></li>
3218 <li><code>none | no</code>
3219 <p>This effectively disables the mutex, and is only allowed for a
3220 mutex if the module indicates that it is a valid choice. Consult the
3221 module documentation for more information.</p></li>
3223 <li><code>posixsem</code>
3224 <p>This is a mutex variant based on a Posix semaphore.</p>
3226 <div class="warning"><h3>Warning</h3>
3227 <p>The semaphore ownership is not recovered if a thread in the process
3228 holding the mutex segfaults, resulting in a hang of the web server.</p>
3232 <li><code>sysvsem</code>
3233 <p>This is a mutex variant based on a SystemV IPC semaphore.</p>
3235 <div class="warning"><h3>Warning</h3>
3236 <p>It is possible to "leak" SysV semaphores if processes crash
3237 before the semaphore is removed.</p>
3240 <div class="warning"><h3>Security</h3>
3241 <p>The semaphore API allows for a denial of service attack by any
3242 CGIs running under the same uid as the webserver (<em>i.e.</em>,
3243 all CGIs, unless you use something like <code class="program"><a href="../programs/suexec.html">suexec</a></code>
3244 or <code>cgiwrapper</code>).</p>
3248 <li><code>sem</code>
3249 <p>This selects the "best" available semaphore implementation, choosing
3250 between Posix and SystemV IPC semaphores, in that order.</p></li>
3252 <li><code>pthread</code>
3253 <p>This is a mutex variant based on cross-process Posix thread
3256 <div class="warning"><h3>Warning</h3>
3257 <p>On most systems, if a child process terminates abnormally while
3258 holding a mutex that uses this implementation, the server will deadlock
3259 and stop responding to requests. When this occurs, the server will
3260 require a manual restart to recover.</p>
3261 <p>Solaris is a notable exception as it provides a mechanism which
3262 usually allows the mutex to be recovered after a child process
3263 terminates abnormally while holding a mutex.</p>
3264 <p>If your system implements the
3265 <code>pthread_mutexattr_setrobust_np()</code> function, you may be able
3266 to use the <code>pthread</code> option safely.</p>
3270 <li><code>fcntl:/path/to/mutex</code>
3271 <p>This is a mutex variant where a physical (lock-)file and the
3272 <code>fcntl()</code> function are used as the mutex.</p>
3274 <div class="warning"><h3>Warning</h3>
3275 <p>When multiple mutexes based on this mechanism are used within
3276 multi-threaded, multi-process environments, deadlock errors (EDEADLK)
3277 can be reported for valid mutex operations if <code>fcntl()</code>
3278 is not thread-aware, such as on Solaris.</p>
3282 <li><code>flock:/path/to/mutex</code>
3283 <p>This is similar to the <code>fcntl:/path/to/mutex</code> method
3284 with the exception that the <code>flock()</code> function is used to
3285 provide file locking.</p></li>
3287 <li><code>file:/path/to/mutex</code>
3288 <p>This selects the "best" available file locking implementation,
3289 choosing between <code>fcntl</code> and <code>flock</code>, in that
3293 <p>Most mechanisms are only available on selected platforms, where the
3294 underlying platform and <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> support it. Mechanisms
3295 which aren't available on all platforms are <em>posixsem</em>,
3296 <em>sysvsem</em>, <em>sem</em>, <em>pthread</em>, <em>fcntl</em>,
3297 <em>flock</em>, and <em>file</em>.</p>
3299 <p>With the file-based mechanisms <em>fcntl</em> and <em>flock</em>,
3300 the path, if provided, is a directory where the lock file will be created.
3301 The default directory is httpd's run-time file directory,
3302 <code class="directive"><a href="#defaultruntimedir">DefaultRuntimeDir</a></code>. If a relative
3303 path is provided, it is relative to
3304 <code class="directive"><a href="#defaultruntimedir">DefaultRuntimeDir</a></code>. Always use a local
3305 disk filesystem for <code>/path/to/mutex</code> and never a directory residing
3306 on a NFS- or AFS-filesystem. The basename of the file will be the mutex
3307 type, an optional instance string provided by the module, and unless the
3308 <code>OmitPID</code> keyword is specified, the process id of the httpd
3309 parent process will be appended to to make the file name unique, avoiding
3310 conflicts when multiple httpd instances share a lock file directory. For
3311 example, if the mutex name is <code>mpm-accept</code> and the lock file
3312 directory is <code>/var/httpd/locks</code>, the lock file name for the
3313 httpd instance with parent process id 12345 would be
3314 <code>/var/httpd/locks/mpm-accept.12345</code>.</p>
3316 <div class="warning"><h3>Security</h3>
3317 <p>It is best to <em>avoid</em> putting mutex files in a world-writable
3318 directory such as <code>/var/tmp</code> because someone could create
3319 a denial of service attack and prevent the server from starting by
3320 creating a lockfile with the same name as the one the server will try
3324 <p>The following table documents the names of mutexes used by httpd
3325 and bundled modules.</p>
3327 <table class="bordered"><tr class="header">
3330 <th>Protected resource</th>
3333 <td><code>mpm-accept</code></td>
3334 <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>
3335 <td>incoming connections, to avoid the thundering herd problem;
3336 for more information, refer to the
3337 <a href="../misc/perf-tuning.html">performance tuning</a>
3341 <td><code>authdigest-client</code></td>
3342 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3343 <td>client list in shared memory</td>
3346 <td><code>authdigest-opaque</code></td>
3347 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3348 <td>counter in shared memory</td>
3351 <td><code>ldap-cache</code></td>
3352 <td><code class="module"><a href="../mod/mod_ldap.html">mod_ldap</a></code></td>
3353 <td>LDAP result cache</td>
3356 <td><code>rewrite-map</code></td>
3357 <td><code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code></td>
3358 <td>communication with external mapping programs, to avoid
3359 intermixed I/O from multiple requests</td>
3362 <td><code>ssl-cache</code></td>
3363 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3364 <td>SSL session cache</td>
3367 <td><code>ssl-stapling</code></td>
3368 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3369 <td>OCSP stapling response cache</td>
3372 <td><code>watchdog-callback</code></td>
3373 <td><code class="module"><a href="../mod/mod_watchdog.html">mod_watchdog</a></code></td>
3374 <td>callback function of a particular client module</td>
3378 <p>The <code>OmitPID</code> keyword suppresses the addition of the httpd
3379 parent process id from the lock file name.</p>
3381 <p>In the following example, the mutex mechanism for the MPM accept
3382 mutex will be changed from the compiled-in default to <code>fcntl</code>,
3383 with the associated lock file created in directory
3384 <code>/var/httpd/locks</code>. The mutex mechanism for all other mutexes
3385 will be changed from the compiled-in default to <code>sysvsem</code>.</p>
3387 <pre class="prettyprint lang-config">Mutex sysvsem default
3388 Mutex fcntl:/var/httpd/locks mpm-accept</pre>
3392 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3393 <div class="directive-section"><h2><a name="NameVirtualHost" id="NameVirtualHost">NameVirtualHost</a> <a name="namevirtualhost" id="namevirtualhost">Directive</a></h2>
3394 <table class="directive">
3395 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>DEPRECATED: Designates an IP address for name-virtual
3397 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NameVirtualHost <var>addr</var>[:<var>port</var>]</code></td></tr>
3398 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3399 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3400 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3403 <p>Prior to 2.3.11, <code class="directive">NameVirtualHost</code> was required
3404 to instruct the server that a particular IP address and port combination
3405 was usable as a name-based virtual host. In 2.3.11 and later,
3406 any time an IP address and port combination is used in multiple virtual
3407 hosts, name-based virtual hosting is automatically enabled for that address.</p>
3409 <p>This directive currently has no effect.</p>
3413 <li><a href="../vhosts/">Virtual Hosts
3414 documentation</a></li>
3417 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3418 <div class="directive-section"><h2><a name="Options" id="Options">Options</a> <a name="options" id="options">Directive</a></h2>
3419 <table class="directive">
3420 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures what features are available in a particular
3422 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Options
3423 [+|-]<var>option</var> [[+|-]<var>option</var>] ...</code></td></tr>
3424 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Options FollowSymlinks</code></td></tr>
3425 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3426 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
3427 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3428 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3429 <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>
3431 <p>The <code class="directive">Options</code> directive controls which
3432 server features are available in a particular directory.</p>
3434 <p><var>option</var> can be set to <code>None</code>, in which
3435 case none of the extra features are enabled, or one or more of
3439 <dt><code>All</code></dt>
3441 <dd>All options except for <code>MultiViews</code>.</dd>
3443 <dt><code>ExecCGI</code></dt>
3446 Execution of CGI scripts using <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>
3449 <dt><code>FollowSymLinks</code></dt>
3452 The server will follow symbolic links in this directory. This is
3453 the default setting.
3455 <p>Even though the server follows the symlink it does <em>not</em>
3456 change the pathname used to match against <code class="directive"><a href="#directory"><Directory></a></code> sections.</p>
3458 <p>The <code>FollowSymLinks</code> and
3459 <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
3460 <code>.htaccess</code> files.</p>
3462 <p>Omitting this option should not be considered a security restriction,
3463 since symlink testing is subject to race conditions that make it
3467 <dt><code>Includes</code></dt>
3470 Server-side includes provided by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
3473 <dt><code>IncludesNOEXEC</code></dt>
3477 Server-side includes are permitted, but the <code>#exec
3478 cmd</code> and <code>#exec cgi</code> are disabled. It is still
3479 possible to <code>#include virtual</code> CGI scripts from
3480 <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>ed
3483 <dt><code>Indexes</code></dt>
3486 If a URL which maps to a directory is requested, and there
3487 is no <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
3488 (<em>e.g.</em>, <code>index.html</code>) in that directory, then
3489 <code class="module"><a href="../mod/mod_autoindex.html">mod_autoindex</a></code> will return a formatted listing
3490 of the directory.</dd>
3492 <dt><code>MultiViews</code></dt>
3495 <a href="../content-negotiation.html">Content negotiated</a>
3496 "MultiViews" are allowed using
3497 <code class="module"><a href="../mod/mod_negotiation.html">mod_negotiation</a></code>.
3498 <div class="note"><h3>Note</h3> <p>This option gets ignored if set
3499 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>
3500 needs real resources to compare against and evaluate from.</p></div>
3503 <dt><code>SymLinksIfOwnerMatch</code></dt>
3505 <dd>The server will only follow symbolic links for which the
3506 target file or directory is owned by the same user id as the
3509 <div class="note"><h3>Note</h3>
3510 <p>The <code>FollowSymLinks</code> and
3511 <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
3512 <code>.htaccess</code> files.</p>
3514 <p>This option should not be considered a security restriction,
3515 since symlink testing is subject to race conditions that make it
3520 <p>Normally, if multiple <code class="directive">Options</code> could
3521 apply to a directory, then the most specific one is used and
3522 others are ignored; the options are not merged. (See <a href="../sections.html#mergin">how sections are merged</a>.)
3523 However if <em>all</em> the options on the
3524 <code class="directive">Options</code> directive are preceded by a
3525 <code>+</code> or <code>-</code> symbol, the options are
3526 merged. Any options preceded by a <code>+</code> are added to the
3527 options currently in force, and any options preceded by a
3528 <code>-</code> are removed from the options currently in
3531 <div class="note"><h3>Note</h3>
3532 <p>Mixing <code class="directive">Options</code> with a <code>+</code> or
3533 <code>-</code> with those without is not valid syntax, and will be
3534 rejected during server startup by the syntax check with an abort.</p>
3537 <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>
3539 <pre class="prettyprint lang-config"><Directory "/web/docs">
3540 Options Indexes FollowSymLinks
3543 <Directory "/web/docs/spec">
3545 </Directory></pre>
3548 <p>then only <code>Includes</code> will be set for the
3549 <code>/web/docs/spec</code> directory. However if the second
3550 <code class="directive">Options</code> directive uses the <code>+</code> and
3551 <code>-</code> symbols:</p>
3553 <pre class="prettyprint lang-config"><Directory "/web/docs">
3554 Options Indexes FollowSymLinks
3557 <Directory "/web/docs/spec">
3558 Options +Includes -Indexes
3559 </Directory></pre>
3562 <p>then the options <code>FollowSymLinks</code> and
3563 <code>Includes</code> are set for the <code>/web/docs/spec</code>
3566 <div class="note"><h3>Note</h3>
3567 <p>Using <code>-IncludesNOEXEC</code> or
3568 <code>-Includes</code> disables server-side includes completely
3569 regardless of the previous setting.</p>
3572 <p>The default in the absence of any other settings is
3573 <code>FollowSymlinks</code>.</p>
3576 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3577 <div class="directive-section"><h2><a name="Protocol" id="Protocol">Protocol</a> <a name="protocol" id="protocol">Directive</a></h2>
3578 <table class="directive">
3579 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Protocol for a listening socket</td></tr>
3580 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Protocol <var>protocol</var></code></td></tr>
3581 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3582 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3583 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3584 <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>
3586 <p>This directive specifies the protocol used for a specific listening socket.
3587 The protocol is used to determine which module should handle a request, and
3588 to apply protocol specific optimizations with the <code class="directive">AcceptFilter</code>
3591 <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>
3593 <p>For example, if you are running <code>https</code> on a non-standard port, specify the protocol explicitly:</p>
3595 <pre class="prettyprint lang-config">Protocol https</pre>
3598 <p>You can also specify the protocol using the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code> directive.</p>
3602 <li><code class="directive"><a href="#acceptfilter">AcceptFilter</a></code></li>
3603 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
3606 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3607 <div class="directive-section"><h2><a name="RegisterHttpMethod" id="RegisterHttpMethod">RegisterHttpMethod</a> <a name="registerhttpmethod" id="registerhttpmethod">Directive</a></h2>
3608 <table class="directive">
3609 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Register non-standard HTTP methods</td></tr>
3610 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>RegisterHttpMethod <var>method</var> [<var>method</var> [...]]</code></td></tr>
3611 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</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>HTTP Methods that are not conforming to the relvant RFCs are normally
3616 rejected by request processing in Apache HTTPD. To avoid this, modules
3617 can register non-standard HTTP methods they support.
3618 The <code class="directive">RegisterHttpMethod</code> allows to register such
3619 methods manually. This can be useful for if such methods are forwared
3620 for external processing, e.g. to a CGI script.</p>
3623 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3624 <div class="directive-section"><h2><a name="RLimitCPU" id="RLimitCPU">RLimitCPU</a> <a name="rlimitcpu" id="rlimitcpu">Directive</a></h2>
3625 <table class="directive">
3626 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the CPU consumption of processes launched
3627 by Apache httpd children</td></tr>
3628 <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>
3629 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3630 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3631 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3632 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3633 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3635 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3636 resource limit for all processes and the second parameter sets
3637 the maximum resource limit. Either parameter can be a number,
3638 or <code>max</code> to indicate to the server that the limit should
3639 be set to the maximum allowed by the operating system
3640 configuration. Raising the maximum resource limit requires that
3641 the server is running as <code>root</code>, or in the initial startup
3644 <p>This applies to processes forked off from Apache httpd children
3645 servicing requests, not the Apache httpd children themselves. This
3646 includes CGI scripts and SSI exec commands, but not any
3647 processes forked off from the Apache httpd parent such as piped
3650 <p>CPU resource limits are expressed in seconds per
3655 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3656 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3659 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3660 <div class="directive-section"><h2><a name="RLimitMEM" id="RLimitMEM">RLimitMEM</a> <a name="rlimitmem" id="rlimitmem">Directive</a></h2>
3661 <table class="directive">
3662 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the memory consumption of processes launched
3663 by Apache httpd children</td></tr>
3664 <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>
3665 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3666 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3667 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3668 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3669 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3671 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3672 resource limit for all processes and the second parameter sets
3673 the maximum resource limit. Either parameter can be a number,
3674 or <code>max</code> to indicate to the server that the limit should
3675 be set to the maximum allowed by the operating system
3676 configuration. Raising the maximum resource limit requires that
3677 the server is running as <code>root</code>, or in the initial startup
3680 <p>This applies to processes forked off from Apache httpd children
3681 servicing requests, not the Apache httpd children themselves. This
3682 includes CGI scripts and SSI exec commands, but not any
3683 processes forked off from the Apache httpd parent such as piped
3686 <p>Memory resource limits are expressed in bytes per
3691 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3692 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3695 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3696 <div class="directive-section"><h2><a name="RLimitNPROC" id="RLimitNPROC">RLimitNPROC</a> <a name="rlimitnproc" id="rlimitnproc">Directive</a></h2>
3697 <table class="directive">
3698 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of processes that can be launched by
3699 processes launched by Apache httpd children</td></tr>
3700 <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>
3701 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3702 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3703 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3704 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3705 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3707 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3708 resource limit for all processes and the second parameter sets
3709 the maximum resource limit. Either parameter can be a number,
3710 or <code>max</code> to indicate to the server that the limit
3711 should be set to the maximum allowed by the operating system
3712 configuration. Raising the maximum resource limit requires that
3713 the server is running as <code>root</code>, or in the initial startup
3716 <p>This applies to processes forked off from Apache httpd children
3717 servicing requests, not the Apache httpd children themselves. This
3718 includes CGI scripts and SSI exec commands, but not any
3719 processes forked off from the Apache httpd parent such as piped
3722 <p>Process limits control the number of processes per user.</p>
3724 <div class="note"><h3>Note</h3>
3725 <p>If CGI processes are <strong>not</strong> running
3726 under user ids other than the web server user id, this directive
3727 will limit the number of processes that the server itself can
3728 create. Evidence of this situation will be indicated by
3729 <strong><code>cannot fork</code></strong> messages in the
3730 <code>error_log</code>.</p>
3735 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3736 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3739 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3740 <div class="directive-section"><h2><a name="ScriptInterpreterSource" id="ScriptInterpreterSource">ScriptInterpreterSource</a> <a name="scriptinterpretersource" id="scriptinterpretersource">Directive</a></h2>
3741 <table class="directive">
3742 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
3744 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ScriptInterpreterSource Registry|Registry-Strict|Script</code></td></tr>
3745 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ScriptInterpreterSource Script</code></td></tr>
3746 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3747 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3748 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3749 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3750 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Win32 only.</td></tr>
3752 <p>This directive is used to control how Apache httpd finds the
3753 interpreter used to run CGI scripts. The default setting is
3754 <code>Script</code>. This causes Apache httpd to use the interpreter pointed to
3755 by the shebang line (first line, starting with <code>#!</code>) in the
3756 script. On Win32 systems this line usually looks like:</p>
3758 <pre class="prettyprint lang-perl">#!C:/Perl/bin/perl.exe</pre>
3761 <p>or, if <code>perl</code> is in the <code>PATH</code>, simply:</p>
3763 <pre class="prettyprint lang-perl">#!perl</pre>
3766 <p>Setting <code>ScriptInterpreterSource Registry</code> will
3767 cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
3768 searched using the script file extension (e.g., <code>.pl</code>) as a
3769 search key. The command defined by the registry subkey
3770 <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
3771 <code>Shell\Open\Command</code> is used to open the script file. If the
3772 registry keys cannot be found, Apache httpd falls back to the behavior of the
3773 <code>Script</code> option.</p>
3775 <div class="warning"><h3>Security</h3>
3776 <p>Be careful when using <code>ScriptInterpreterSource
3777 Registry</code> with <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>'ed directories, because
3778 Apache httpd will try to execute <strong>every</strong> file within this
3779 directory. The <code>Registry</code> setting may cause undesired
3780 program calls on files which are typically not executed. For
3781 example, the default open command on <code>.htm</code> files on
3782 most Windows systems will execute Microsoft Internet Explorer, so
3783 any HTTP request for an <code>.htm</code> file existing within the
3784 script directory would start the browser in the background on the
3785 server. This is a good way to crash your system within a minute or
3789 <p>The option <code>Registry-Strict</code> which is new in Apache HTTP Server
3790 2.0 does the same thing as <code>Registry</code> but uses only the
3791 subkey <code>Shell\ExecCGI\Command</code>. The
3792 <code>ExecCGI</code> key is not a common one. It must be
3793 configured manually in the windows registry and hence prevents
3794 accidental program calls on your system.</p>
3797 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3798 <div class="directive-section"><h2><a name="SeeRequestTail" id="SeeRequestTail">SeeRequestTail</a> <a name="seerequesttail" id="seerequesttail">Directive</a></h2>
3799 <table class="directive">
3800 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine if mod_status displays the first 63 characters
3801 of a request or the last 63, assuming the request itself is greater than
3803 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SeeRequestTail On|Off</code></td></tr>
3804 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SeeRequestTail Off</code></td></tr>
3805 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3806 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3807 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3809 <p>mod_status with <code>ExtendedStatus On</code>
3810 displays the actual request being handled.
3811 For historical purposes, only 63 characters of the request
3812 are actually stored for display purposes. This directive
3813 controls whether the 1st 63 characters are stored (the previous
3814 behavior and the default) or if the last 63 characters are. This
3815 is only applicable, of course, if the length of the request is
3816 64 characters or greater.</p>
3818 <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:
3821 <table class="bordered">
3823 <th>Off (default)</th>
3824 <td>GET /disk1/storage/apache/htdocs/images/imagestore1/food/apples</td>
3828 <td>orage/apache/htdocs/images/imagestore1/food/apples.jpg HTTP/1.1</td>
3834 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3835 <div class="directive-section"><h2><a name="ServerAdmin" id="ServerAdmin">ServerAdmin</a> <a name="serveradmin" id="serveradmin">Directive</a></h2>
3836 <table class="directive">
3837 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Email address that the server includes in error
3838 messages sent to the client</td></tr>
3839 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAdmin <var>email-address</var>|<var>URL</var></code></td></tr>
3840 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3841 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3842 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3844 <p>The <code class="directive">ServerAdmin</code> sets the contact address
3845 that the server includes in any error messages it returns to the
3846 client. If the <code>httpd</code> doesn't recognize the supplied argument
3848 assumes, that it's an <var>email-address</var> and prepends it with
3849 <code>mailto:</code> in hyperlink targets. However, it's recommended to
3850 actually use an email address, since there are a lot of CGI scripts that
3851 make that assumption. If you want to use an URL, it should point to another
3852 server under your control. Otherwise users may not be able to contact you in
3855 <p>It may be worth setting up a dedicated address for this, e.g.</p>
3857 <pre class="prettyprint lang-config">ServerAdmin www-admin@foo.example.com</pre>
3859 <p>as users do not always mention that they are talking about the
3863 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3864 <div class="directive-section"><h2><a name="ServerAlias" id="ServerAlias">ServerAlias</a> <a name="serveralias" id="serveralias">Directive</a></h2>
3865 <table class="directive">
3866 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Alternate names for a host used when matching requests
3867 to name-virtual hosts</td></tr>
3868 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</code></td></tr>
3869 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
3870 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3871 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3873 <p>The <code class="directive">ServerAlias</code> directive sets the
3874 alternate names for a host, for use with <a href="../vhosts/name-based.html">name-based virtual hosts</a>. The
3875 <code class="directive">ServerAlias</code> may include wildcards, if appropriate.</p>
3877 <pre class="prettyprint lang-config"><VirtualHost *:80>
3878 ServerName server.example.com
3879 ServerAlias server server2.example.com server2
3880 ServerAlias *.example.com
3881 UseCanonicalName Off
3883 </VirtualHost></pre>
3886 <p>Name-based virtual hosts for the best-matching set of <code class="directive"><a href="#virtualhost"><virtualhost></a></code>s are processed
3887 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
3888 (nor for ServerName vs. ServerAlias). </p>
3890 <p>The complete list of names in the <code class="directive">VirtualHost</code>
3891 directive are treated just like a (non wildcard)
3892 <code class="directive">ServerAlias</code>.</p>
3897 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3898 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
3901 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3902 <div class="directive-section"><h2><a name="ServerName" id="ServerName">ServerName</a> <a name="servername" id="servername">Directive</a></h2>
3903 <table class="directive">
3904 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hostname and port that the server uses to identify
3906 <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>
3907 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3908 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3909 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3911 <p>The <code class="directive">ServerName</code> directive sets the
3912 request scheme, hostname and
3913 port that the server uses to identify itself. This is used when
3914 creating redirection URLs.</p>
3916 <p>Additionally, <code class="directive">ServerName</code> is used (possibly
3917 in conjunction with <code class="directive">ServerAlias</code>) to uniquely
3918 identify a virtual host, when using <a href="../vhosts/name-based.html">name-based virtual hosts</a>.</p>
3920 <p>For example, if the name of the
3921 machine hosting the web server is <code>simple.example.com</code>,
3922 but the machine also has the DNS alias <code>www.example.com</code>
3923 and you wish the web server to be so identified, the following
3924 directive should be used:</p>
3926 <pre class="prettyprint lang-config">ServerName www.example.com</pre>
3929 <p>The <code class="directive">ServerName</code> directive
3930 may appear anywhere within the definition of a server. However,
3931 each appearance overrides the previous appearance (within that
3934 <p>If no <code class="directive">ServerName</code> is specified, then the
3935 server attempts to deduce the client visible hostname by performing a
3936 reverse lookup on an IP address of the systems hostname.</p>
3938 <p>If no port is specified in the
3939 <code class="directive">ServerName</code>, then the server will use the
3940 port from the incoming request. For optimal reliability and
3941 predictability, you should specify an explicit hostname and port
3942 using the <code class="directive">ServerName</code> directive.</p>
3944 <p>If you are using <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
3945 the <code class="directive">ServerName</code> inside a
3946 <code class="directive"><a href="#virtualhost"><VirtualHost></a></code>
3947 section specifies what hostname must appear in the request's
3948 <code>Host:</code> header to match this virtual host.</p>
3950 <p>Sometimes, the server runs behind a device that processes SSL,
3951 such as a reverse proxy, load balancer or SSL offload
3952 appliance. When this is the case, specify the
3953 <code>https://</code> scheme and the port number to which the
3954 clients connect in the <code class="directive">ServerName</code> directive
3955 to make sure that the server generates the correct
3956 self-referential URLs.
3959 <p>See the description of the
3960 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> and
3961 <code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code> directives for
3962 settings which determine whether self-referential URLs (e.g., by the
3963 <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> module) will refer to the
3964 specified port, or to the port number given in the client's request.
3967 <div class="warning">
3968 <p>Failure to set <code class="directive">ServerName</code> to a name that
3969 your server can resolve to an IP address will result in a startup
3970 warning. <code>httpd</code> will then use whatever hostname it can
3971 determine, using the system's <code>hostname</code> command. This
3972 will almost never be the hostname you actually want.</p>
3973 <div class="example"><p><code>
3974 httpd: Could not reliably determine the server's fully qualified domain name, using rocinante.local for ServerName
3981 <li><a href="../dns-caveats.html">Issues Regarding DNS and
3982 Apache HTTP Server</a></li>
3983 <li><a href="../vhosts/">Apache HTTP Server virtual host
3984 documentation</a></li>
3985 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3986 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
3987 <li><code class="directive"><a href="#serveralias">ServerAlias</a></code></li>
3990 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3991 <div class="directive-section"><h2><a name="ServerPath" id="ServerPath">ServerPath</a> <a name="serverpath" id="serverpath">Directive</a></h2>
3992 <table class="directive">
3993 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Legacy URL pathname for a name-based virtual host that
3994 is accessed by an incompatible browser</td></tr>
3995 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerPath <var>URL-path</var></code></td></tr>
3996 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
3997 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3998 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4000 <p>The <code class="directive">ServerPath</code> directive sets the legacy
4001 URL pathname for a host, for use with <a href="../vhosts/">name-based virtual hosts</a>.</p>
4005 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4008 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4009 <div class="directive-section"><h2><a name="ServerRoot" id="ServerRoot">ServerRoot</a> <a name="serverroot" id="serverroot">Directive</a></h2>
4010 <table class="directive">
4011 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server installation</td></tr>
4012 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerRoot <var>directory-path</var></code></td></tr>
4013 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerRoot /usr/local/apache</code></td></tr>
4014 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4015 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4016 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4018 <p>The <code class="directive">ServerRoot</code> directive sets the
4019 directory in which the server lives. Typically it will contain the
4020 subdirectories <code>conf/</code> and <code>logs/</code>. Relative
4021 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
4022 relative to this directory.</p>
4024 <pre class="prettyprint lang-config">ServerRoot "/home/httpd"</pre>
4027 <p>The default location of <code class="directive">ServerRoot</code> may be
4028 modified by using the <code>--prefix</code> argument to
4029 <a href="../programs/configure.html"><code>configure</code></a>, and
4030 most third-party distributions of the server have a different
4031 default location from the one listed above.</p>
4036 <li><a href="../invoking.html">the <code>-d</code>
4037 option to <code>httpd</code></a></li>
4038 <li><a href="../misc/security_tips.html#serverroot">the
4039 security tips</a> for information on how to properly set
4040 permissions on the <code class="directive">ServerRoot</code></li>
4043 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4044 <div class="directive-section"><h2><a name="ServerSignature" id="ServerSignature">ServerSignature</a> <a name="serversignature" id="serversignature">Directive</a></h2>
4045 <table class="directive">
4046 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the footer on server-generated documents</td></tr>
4047 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerSignature On|Off|EMail</code></td></tr>
4048 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerSignature Off</code></td></tr>
4049 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4050 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
4051 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4052 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4054 <p>The <code class="directive">ServerSignature</code> directive allows the
4055 configuration of a trailing footer line under server-generated
4056 documents (error messages, <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> ftp directory
4057 listings, <code class="module"><a href="../mod/mod_info.html">mod_info</a></code> output, ...). The reason why you
4058 would want to enable such a footer line is that in a chain of proxies,
4059 the user often has no possibility to tell which of the chained servers
4060 actually produced a returned error message.</p>
4062 <p>The <code>Off</code>
4063 setting, which is the default, suppresses the footer line (and is
4064 therefore compatible with the behavior of Apache-1.2 and
4065 below). The <code>On</code> setting simply adds a line with the
4066 server version number and <code class="directive"><a href="#servername">ServerName</a></code> of the serving virtual host,
4067 and the <code>EMail</code> setting additionally creates a
4068 "mailto:" reference to the <code class="directive"><a href="#serveradmin">ServerAdmin</a></code> of the referenced
4071 <p>After version 2.0.44, the details of the server version number
4072 presented are controlled by the <code class="directive"><a href="#servertokens">ServerTokens</a></code> directive.</p>
4076 <li><code class="directive"><a href="#servertokens">ServerTokens</a></code></li>
4079 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4080 <div class="directive-section"><h2><a name="ServerTokens" id="ServerTokens">ServerTokens</a> <a name="servertokens" id="servertokens">Directive</a></h2>
4081 <table class="directive">
4082 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the <code>Server</code> HTTP response
4084 <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>
4085 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerTokens Full</code></td></tr>
4086 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4087 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4088 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4090 <p>This directive controls whether <code>Server</code> response
4091 header field which is sent back to clients includes a
4092 description of the generic OS-type of the server as well as
4093 information about compiled-in modules.</p>
4096 <dt><code>ServerTokens Full</code> (or not specified)</dt>
4098 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4099 (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
4101 <dt><code>ServerTokens Prod[uctOnly]</code></dt>
4103 <dd>Server sends (<em>e.g.</em>): <code>Server:
4106 <dt><code>ServerTokens Major</code></dt>
4108 <dd>Server sends (<em>e.g.</em>): <code>Server:
4109 Apache/2</code></dd>
4111 <dt><code>ServerTokens Minor</code></dt>
4113 <dd>Server sends (<em>e.g.</em>): <code>Server:
4114 Apache/2.4</code></dd>
4116 <dt><code>ServerTokens Min[imal]</code></dt>
4118 <dd>Server sends (<em>e.g.</em>): <code>Server:
4119 Apache/2.4.2</code></dd>
4121 <dt><code>ServerTokens OS</code></dt>
4123 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4128 <p>This setting applies to the entire server, and cannot be
4129 enabled or disabled on a virtualhost-by-virtualhost basis.</p>
4131 <p>After version 2.0.44, this directive also controls the
4132 information presented by the <code class="directive"><a href="#serversignature">ServerSignature</a></code> directive.</p>
4134 <div class="note">Setting <code class="directive">ServerTokens</code> to less than
4135 <code>minimal</code> is not recommended because it makes it more
4136 difficult to debug interoperational problems. Also note that
4137 disabling the Server: header does nothing at all to make your
4138 server more secure; the idea of "security through obscurity"
4139 is a myth and leads to a false sense of safety.</div>
4144 <li><code class="directive"><a href="#serversignature">ServerSignature</a></code></li>
4147 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4148 <div class="directive-section"><h2><a name="SetHandler" id="SetHandler">SetHandler</a> <a name="sethandler" id="sethandler">Directive</a></h2>
4149 <table class="directive">
4150 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be processed by a
4152 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetHandler <var>handler-name</var>|None</code></td></tr>
4153 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4154 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4155 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4156 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4158 <p>When placed into an <code>.htaccess</code> file or a
4159 <code class="directive"><a href="#directory"><Directory></a></code> or
4160 <code class="directive"><a href="#location"><Location></a></code>
4161 section, this directive forces all matching files to be parsed
4162 through the <a href="../handler.html">handler</a> given by
4163 <var>handler-name</var>. For example, if you had a directory you
4164 wanted to be parsed entirely as imagemap rule files, regardless
4165 of extension, you might put the following into an
4166 <code>.htaccess</code> file in that directory:</p>
4168 <pre class="prettyprint lang-config">SetHandler imap-file</pre>
4171 <p>Another example: if you wanted to have the server display a
4172 status report whenever a URL of
4173 <code>http://servername/status</code> was called, you might put
4174 the following into <code>httpd.conf</code>:</p>
4176 <pre class="prettyprint lang-config"><Location "/status">
4177 SetHandler server-status
4178 </Location></pre>
4181 <p>You could also use this directive to configure a particular
4182 handler for files with a particular file extension. For example:</p>
4184 <pre class="prettyprint lang-config"><FilesMatch \.php$>
4185 SetHandler application/x-httpd-php
4186 </FilesMatch></pre>
4189 <p>You can override an earlier defined <code class="directive">SetHandler</code>
4190 directive by using the value <code>None</code>.</p>
4192 <div class="note"><h3>Note</h3>
4193 <p>Because <code class="directive">SetHandler</code> overrides default handlers,
4194 normal behavior such as handling of URLs ending in a slash (/) as
4195 directories or index files is suppressed.</p></div>
4199 <li><code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code></li>
4202 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4203 <div class="directive-section"><h2><a name="SetInputFilter" id="SetInputFilter">SetInputFilter</a> <a name="setinputfilter" id="setinputfilter">Directive</a></h2>
4204 <table class="directive">
4205 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process client requests and POST
4207 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetInputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4208 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4209 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4210 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4211 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4213 <p>The <code class="directive">SetInputFilter</code> directive sets the
4214 filter or filters which will process client requests and POST
4215 input when they are received by the server. This is in addition to
4216 any filters defined elsewhere, including the
4217 <code class="directive"><a href="../mod/mod_mime.html#addinputfilter">AddInputFilter</a></code>
4220 <p>If more than one filter is specified, they must be separated
4221 by semicolons in the order in which they should process the
4226 <li><a href="../filter.html">Filters</a> documentation</li>
4229 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4230 <div class="directive-section"><h2><a name="SetOutputFilter" id="SetOutputFilter">SetOutputFilter</a> <a name="setoutputfilter" id="setoutputfilter">Directive</a></h2>
4231 <table class="directive">
4232 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process responses from the
4234 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4235 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4236 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4237 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4238 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4240 <p>The <code class="directive">SetOutputFilter</code> directive sets the filters
4241 which will process responses from the server before they are
4242 sent to the client. This is in addition to any filters defined
4243 elsewhere, including the
4244 <code class="directive"><a href="../mod/mod_mime.html#addoutputfilter">AddOutputFilter</a></code>
4247 <p>For example, the following configuration will process all files
4248 in the <code>/www/data/</code> directory for server-side
4251 <pre class="prettyprint lang-config"><Directory "/www/data/">
4252 SetOutputFilter INCLUDES
4253 </Directory></pre>
4256 <p>If more than one filter is specified, they must be separated
4257 by semicolons in the order in which they should process the
4262 <li><a href="../filter.html">Filters</a> documentation</li>
4265 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4266 <div class="directive-section"><h2><a name="TimeOut" id="TimeOut">TimeOut</a> <a name="timeout" id="timeout">Directive</a></h2>
4267 <table class="directive">
4268 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for
4269 certain events before failing a request</td></tr>
4270 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TimeOut <var>seconds</var></code></td></tr>
4271 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TimeOut 60</code></td></tr>
4272 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4273 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4274 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4276 <p>The <code class="directive">TimeOut</code> directive defines the length
4277 of time Apache httpd will wait for I/O in various circumstances:</p>
4280 <li>When reading data from the client, the length of time to
4281 wait for a TCP packet to arrive if the read buffer is
4284 <li>When writing data to the client, the length of time to wait
4285 for an acknowledgement of a packet if the send buffer is
4288 <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>,
4289 the length of time to wait for output from a CGI script.</li>
4291 <li>In <code class="module"><a href="../mod/mod_ext_filter.html">mod_ext_filter</a></code>, the length of time to
4292 wait for output from a filtering process.</li>
4294 <li>In <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>, the default timeout value if
4295 <code class="directive"><a href="../mod/mod_proxy.html#proxytimeout">ProxyTimeout</a></code> is not
4301 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4302 <div class="directive-section"><h2><a name="TraceEnable" id="TraceEnable">TraceEnable</a> <a name="traceenable" id="traceenable">Directive</a></h2>
4303 <table class="directive">
4304 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines the behavior on <code>TRACE</code> requests</td></tr>
4305 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TraceEnable <var>[on|off|extended]</var></code></td></tr>
4306 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TraceEnable on</code></td></tr>
4307 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4308 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4309 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4311 <p>This directive overrides the behavior of <code>TRACE</code> for both
4312 the core server and <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>. The default
4313 <code>TraceEnable on</code> permits <code>TRACE</code> requests per
4314 RFC 2616, which disallows any request body to accompany the request.
4315 <code>TraceEnable off</code> causes the core server and
4316 <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> to return a <code>405</code> (Method not
4317 allowed) error to the client.</p>
4319 <p>Finally, for testing and diagnostic purposes only, request
4320 bodies may be allowed using the non-compliant <code>TraceEnable
4321 extended</code> directive. The core (as an origin server) will
4322 restrict the request body to 64k (plus 8k for chunk headers if
4323 <code>Transfer-Encoding: chunked</code> is used). The core will
4324 reflect the full headers and all chunk headers with the response
4325 body. As a proxy server, the request body is not restricted to 64k.</p>
4327 <div class="note"><h3>Note</h3>
4328 <p>Despite claims to the contrary, <code>TRACE</code> is not
4329 a security vulnerability and there is no viable reason for
4330 it to be disabled. Doing so necessarily makes your server
4335 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4336 <div class="directive-section"><h2><a name="UnDefine" id="UnDefine">UnDefine</a> <a name="undefine" id="undefine">Directive</a></h2>
4337 <table class="directive">
4338 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Undefine the existence of a variable</td></tr>
4339 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UnDefine <var>parameter-name</var></code></td></tr>
4340 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4341 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4342 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4344 <p>Undoes the effect of a <code class="directive"><a href="#define">Define</a></code> or
4345 of passing a <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</p>
4346 <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
4347 <code>-D</code> arguments in any startup scripts.</p>
4348 <p>While this directive is supported in virtual host context,
4349 the changes it makes are visible to any later configuration
4350 directives, beyond any enclosing virtual host</p>
4353 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4354 <div class="directive-section"><h2><a name="UseCanonicalName" id="UseCanonicalName">UseCanonicalName</a> <a name="usecanonicalname" id="usecanonicalname">Directive</a></h2>
4355 <table class="directive">
4356 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own name and
4358 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalName On|Off|DNS</code></td></tr>
4359 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalName Off</code></td></tr>
4360 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4361 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4362 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4364 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4365 URL -- that is, a URL that refers back to the same server. With
4366 <code>UseCanonicalName On</code> Apache httpd will use the hostname and port
4367 specified in the <code class="directive"><a href="#servername">ServerName</a></code>
4368 directive to construct the canonical name for the server. This name
4369 is used in all self-referential URLs, and for the values of
4370 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>
4372 <p>With <code>UseCanonicalName Off</code> Apache httpd will form
4373 self-referential URLs using the hostname and port supplied by
4374 the client if any are supplied (otherwise it will use the
4375 canonical name, as defined above). These values are the same
4376 that are used to implement <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
4377 and are available with the same clients. The CGI variables
4378 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
4379 constructed from the client supplied values as well.</p>
4381 <p>An example where this may be useful is on an intranet server
4382 where you have users connecting to the machine using short
4383 names such as <code>www</code>. You'll notice that if the users
4384 type a shortname, and a URL which is a directory, such as
4385 <code>http://www/splat</code>, <em>without the trailing
4386 slash</em> then Apache httpd will redirect them to
4387 <code>http://www.example.com/splat/</code>. If you have
4388 authentication enabled, this will cause the user to have to
4389 authenticate twice (once for <code>www</code> and once again
4390 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">
4391 the FAQ on this subject for more information</a>). But if
4392 <code class="directive">UseCanonicalName</code> is set <code>Off</code>, then
4393 Apache httpd will redirect to <code>http://www/splat/</code>.</p>
4395 <p>There is a third option, <code>UseCanonicalName DNS</code>,
4396 which is intended for use with mass IP-based virtual hosting to
4397 support ancient clients that do not provide a
4398 <code>Host:</code> header. With this option Apache httpd does a
4399 reverse DNS lookup on the server IP address that the client
4400 connected to in order to work out self-referential URLs.</p>
4402 <div class="warning"><h3>Warning</h3>
4403 <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>
4404 they may be broken by this option. The client is essentially free
4405 to give whatever value they want as a hostname. But if the CGI is
4406 only using <code>SERVER_NAME</code> to construct self-referential URLs
4407 then it should be just fine.</p>
4412 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
4413 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4414 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4417 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4418 <div class="directive-section"><h2><a name="UseCanonicalPhysicalPort" id="UseCanonicalPhysicalPort">UseCanonicalPhysicalPort</a> <a name="usecanonicalphysicalport" id="usecanonicalphysicalport">Directive</a></h2>
4419 <table class="directive">
4420 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own port</td></tr>
4421 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalPhysicalPort On|Off</code></td></tr>
4422 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalPhysicalPort Off</code></td></tr>
4423 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4424 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4425 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4427 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4428 URL -- that is, a URL that refers back to the same server. With
4429 <code>UseCanonicalPhysicalPort On</code> Apache httpd will, when
4430 constructing the canonical port for the server to honor
4431 the <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> directive,
4432 provide the actual physical port number being used by this request
4433 as a potential port. With <code>UseCanonicalPhysicalPort Off</code>
4434 Apache httpd will not ever use the actual physical port number, instead
4435 relying on all configured information to construct a valid port number.</p>
4437 <div class="note"><h3>Note</h3>
4438 <p>The ordering of the lookup when the physical port is used is as
4441 <dt><code>UseCanonicalName On</code></dt>
4444 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4445 <li>Physical port</li>
4446 <li>Default port</li>
4449 <dt><code>UseCanonicalName Off | DNS</code></dt>
4452 <li>Parsed port from <code>Host:</code> header</li>
4453 <li>Physical port</li>
4454 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4455 <li>Default port</li>
4460 <p>With <code>UseCanonicalPhysicalPort Off</code>, the
4461 physical ports are removed from the ordering.</p>
4467 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
4468 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4469 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4472 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4473 <div class="directive-section"><h2><a name="VirtualHost" id="VirtualHost"><VirtualHost></a> <a name="virtualhost" id="virtualhost">Directive</a></h2>
4474 <table class="directive">
4475 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only to a specific
4476 hostname or IP address</td></tr>
4477 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><VirtualHost
4478 <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
4479 ...> ... </VirtualHost></code></td></tr>
4480 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4481 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4482 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4484 <p><code class="directive"><VirtualHost></code> and
4485 <code></VirtualHost></code> are used to enclose a group of
4486 directives that will apply only to a particular virtual host. Any
4487 directive that is allowed in a virtual host context may be
4488 used. When the server receives a request for a document on a
4489 particular virtual host, it uses the configuration directives
4490 enclosed in the <code class="directive"><VirtualHost></code>
4491 section. <var>Addr</var> can be any of the following, optionally followed by
4492 a colon and a port number (or *):</p>
4495 <li>The IP address of the virtual host;</li>
4497 <li>A fully qualified domain name for the IP address of the
4498 virtual host (not recommended);</li>
4500 <li>The character <code>*</code>, which acts as a wildcard and matches
4501 any IP address.</li>
4503 <li>The string <code>_default_</code>, which is an alias for <code>*</code></li>
4507 <pre class="prettyprint lang-config"><VirtualHost 10.1.2.3:80>
4508 ServerAdmin webmaster@host.example.com
4509 DocumentRoot /www/docs/host.example.com
4510 ServerName host.example.com
4511 ErrorLog logs/host.example.com-error_log
4512 TransferLog logs/host.example.com-access_log
4513 </VirtualHost></pre>
4517 <p>IPv6 addresses must be specified in square brackets because
4518 the optional port number could not be determined otherwise. An
4519 IPv6 example is shown below:</p>
4521 <pre class="prettyprint lang-config"><VirtualHost [2001:db8::a00:20ff:fea7:ccea]:80>
4522 ServerAdmin webmaster@host.example.com
4523 DocumentRoot /www/docs/host.example.com
4524 ServerName host.example.com
4525 ErrorLog logs/host.example.com-error_log
4526 TransferLog logs/host.example.com-access_log
4527 </VirtualHost></pre>
4530 <p>Each Virtual Host must correspond to a different IP address,
4531 different port number or a different host name for the server,
4532 in the former case the server machine must be configured to
4533 accept IP packets for multiple addresses. (If the machine does
4534 not have multiple network interfaces, then this can be
4535 accomplished with the <code>ifconfig alias</code> command -- if
4536 your OS supports it).</p>
4538 <div class="note"><h3>Note</h3>
4539 <p>The use of <code class="directive"><VirtualHost></code> does
4540 <strong>not</strong> affect what addresses Apache httpd listens on. You
4541 may need to ensure that Apache httpd is listening on the correct addresses
4542 using <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>.</p>
4545 <p>A <code class="directive"><a href="#servername">ServerName</a></code> should be
4546 specified inside each <code class="directive"><VirtualHost></code> block. If it is absent, the
4547 <code class="directive"><a href="#servername">ServerName</a></code> from the "main"
4548 server configuration will be inherited.</p>
4550 <p>When a request is received, the server first maps it to the best matching
4551 <code class="directive"><VirtualHost></code> based on the local
4552 IP address and port combination only. Non-wildcards have a higher
4553 precedence. If no match based on IP and port occurs at all, the
4554 "main" server configuration is used.</p>
4556 <p>If multiple virtual hosts contain the best matching IP address and port,
4557 the server selects from these virtual hosts the best match based on the
4558 requested hostname. If no matching name-based virtual host is found,
4559 then the first listed virtual host that matched the IP address will be
4560 used. As a consequence, the first listed virtual host for a given IP address
4561 and port combination is default virtual host for that IP and port
4564 <div class="warning"><h3>Security</h3>
4565 <p>See the <a href="../misc/security_tips.html">security tips</a>
4566 document for details on why your security could be compromised if the
4567 directory where log files are stored is writable by anyone other
4568 than the user that starts the server.</p>
4573 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4574 <li><a href="../dns-caveats.html">Issues Regarding DNS and
4575 Apache HTTP Server</a></li>
4576 <li><a href="../bind.html">Setting
4577 which addresses and ports Apache HTTP Server uses</a></li>
4578 <li><a href="../sections.html">How <Directory>, <Location>
4579 and <Files> sections work</a> for an explanation of how these
4580 different sections are combined when a request is received</li>
4583 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4584 <div class="directive-section"><h2><a name="Warning" id="Warning">Warning</a> <a name="warning" id="warning">Directive</a></h2>
4585 <table class="directive">
4586 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Warn from configuration parsing with a custom message</td></tr>
4587 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Warning <var>message</var></code></td></tr>
4588 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4589 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4590 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4591 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.5 and later</td></tr>
4593 <p>If an issue can be detected from within the configuration, this
4594 directive can be used to generate a custom warning message. The
4595 configuration parsing is not halted. The typical use it to check
4596 whether some user define options are set, and warn if not.</p>
4598 <pre class="prettyprint lang-config"># Example
4599 # tell when ReverseProxy is not set
4600 <IfDefine !ReverseProxy>
4601 Warning "reverse proxy is not started, hope this is okay!"
4604 <IfDefine ReverseProxy>
4605 # define custom proxy configuration
4606 </IfDefine></pre>
4612 <div class="bottomlang">
4613 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
4614 <a href="../en/mod/core.html" title="English"> en </a> |
4615 <a href="../es/mod/core.html" hreflang="es" rel="alternate" title="Español"> es </a> |
4616 <a href="../fr/mod/core.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
4617 <a href="../ja/mod/core.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
4618 <a href="../tr/mod/core.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p>
4619 </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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4621 var comments_shortname = 'httpd';
4622 var comments_identifier = 'http://httpd.apache.org/docs/trunk/mod/core.html';
4624 if (w.location.hostname.toLowerCase() == "httpd.apache.org") {
4625 d.write('<div id="comments_thread"><\/div>');
4626 var s = d.createElement('script');
4627 s.type = 'text/javascript';
4629 s.src = 'https://comments.apache.org/show_comments.lua?site=' + comments_shortname + '&page=' + comments_identifier;
4630 (d.getElementsByTagName('head')[0] || d.getElementsByTagName('body')[0]).appendChild(s);
4633 d.write('<div id="comments_thread">Comments are disabled for this page at the moment.<\/div>');
4635 })(window, document);
4636 //--><!]]></script></div><div id="footer">
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