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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>From 2.4.13, <a href="../expr.html">expression syntax</a> can be
1310 used inside the directive to produce dynamic strings and URLs.</p>
1312 <p>URLs can begin with a slash (/) for local web-paths (relative
1313 to the <code class="directive"><a href="#documentroot">DocumentRoot</a></code>), or be a
1314 full URL which the client can resolve. Alternatively, a message
1315 can be provided to be displayed by the browser. Note that deciding
1316 whether the parameter is an URL, a path or a message is performed
1317 before any expression is parsed. Examples:</p>
1319 <pre class="prettyprint lang-config">ErrorDocument 500 http://foo.example.com/cgi-bin/tester
1320 ErrorDocument 404 /cgi-bin/bad_urls.pl
1321 ErrorDocument 401 /subscription_info.html
1322 ErrorDocument 403 "Sorry can't allow you access today"
1323 ErrorDocument 403 Forbidden!
1324 ErrorDocument 403 /cgi-bin/forbidden.pl?referrer=%{escape:%{HTTP_REFERER}}</pre>
1327 <p>Additionally, the special value <code>default</code> can be used
1328 to specify Apache httpd's simple hardcoded message. While not required
1329 under normal circumstances, <code>default</code> will restore
1330 Apache httpd's simple hardcoded message for configurations that would
1331 otherwise inherit an existing <code class="directive">ErrorDocument</code>.</p>
1333 <pre class="prettyprint lang-config">ErrorDocument 404 /cgi-bin/bad_urls.pl
1335 <Directory /web/docs>
1336 ErrorDocument 404 default
1337 </Directory></pre>
1340 <p>Note that when you specify an <code class="directive">ErrorDocument</code>
1341 that points to a remote URL (ie. anything with a method such as
1342 <code>http</code> in front of it), Apache HTTP Server will send a redirect to the
1343 client to tell it where to find the document, even if the
1344 document ends up being on the same server. This has several
1345 implications, the most important being that the client will not
1346 receive the original error status code, but instead will
1347 receive a redirect status code. This in turn can confuse web
1348 robots and other clients which try to determine if a URL is
1349 valid using the status code. In addition, if you use a remote
1350 URL in an <code>ErrorDocument 401</code>, the client will not
1351 know to prompt the user for a password since it will not
1352 receive the 401 status code. Therefore, <strong>if you use an
1353 <code>ErrorDocument 401</code> directive then it must refer to a local
1354 document.</strong></p>
1356 <p>Microsoft Internet Explorer (MSIE) will by default ignore
1357 server-generated error messages when they are "too small" and substitute
1358 its own "friendly" error messages. The size threshold varies depending on
1359 the type of error, but in general, if you make your error document
1360 greater than 512 bytes, then MSIE will show the server-generated
1361 error rather than masking it. More information is available in
1362 Microsoft Knowledge Base article <a href="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q294807">Q294807</a>.</p>
1364 <p>Although most error messages can be overridden, there are certain
1365 circumstances where the internal messages are used regardless of the
1366 setting of <code class="directive"><a href="#errordocument">ErrorDocument</a></code>. In
1367 particular, if a malformed request is detected, normal request processing
1368 will be immediately halted and the internal error message returned.
1369 This is necessary to guard against security problems caused by
1372 <p>If you are using mod_proxy, you may wish to enable
1373 <code class="directive"><a href="../mod/mod_proxy.html#proxyerroroverride">ProxyErrorOverride</a></code> so that you can provide
1374 custom error messages on behalf of your Origin servers. If you don't enable ProxyErrorOverride,
1375 Apache httpd will not generate custom error documents for proxied content.</p>
1379 <li><a href="../custom-error.html">documentation of
1380 customizable responses</a></li>
1383 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1384 <div class="directive-section"><h2><a name="ErrorLog" id="ErrorLog">ErrorLog</a> <a name="errorlog" id="errorlog">Directive</a></h2>
1385 <table class="directive">
1386 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Location where the server will log errors</td></tr>
1387 <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>
1388 <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>
1389 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1390 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1391 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1393 <p>The <code class="directive">ErrorLog</code> directive sets the name of
1394 the file to which the server will log any errors it encounters. If
1395 the <var>file-path</var> is not absolute then it is assumed to be
1396 relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1398 <pre class="prettyprint lang-config">ErrorLog "/var/log/httpd/error_log"</pre>
1401 <p>If the <var>file-path</var>
1402 begins with a pipe character "<code>|</code>" then it is assumed to be a
1403 command to spawn to handle the error log.</p>
1405 <pre class="prettyprint lang-config">ErrorLog "|/usr/local/bin/httpd_errors"</pre>
1408 <p>See the notes on <a href="../logs.html#piped">piped logs</a> for
1409 more information.</p>
1411 <p>Using <code>syslog</code> instead of a filename enables logging
1412 via syslogd(8) if the system supports it and if <code class="module"><a href="../mod/mod_syslog.html">mod_syslog</a></code>
1413 is loaded. The default is to use syslog facility <code>local7</code>,
1414 but you can override this by using the <code>syslog:<var>facility</var></code>
1415 syntax where <var>facility</var> can be one of the names usually documented in
1416 syslog(1). The facility is effectively global, and if it is changed
1417 in individual virtual hosts, the final facility specified affects the
1420 <pre class="prettyprint lang-config">ErrorLog syslog:user</pre>
1423 <p>Additional modules can provide their own ErrorLog providers. The syntax
1424 is similar to <code>syslog</code> example above.</p>
1426 <p>SECURITY: See the <a href="../misc/security_tips.html#serverroot">security tips</a>
1427 document for details on why your security could be compromised
1428 if the directory where log files are stored is writable by
1429 anyone other than the user that starts the server.</p>
1430 <div class="warning"><h3>Note</h3>
1431 <p>When entering a file path on non-Unix platforms, care should be taken
1432 to make sure that only forward slashes are used even though the platform
1433 may allow the use of back slashes. In general it is a good idea to always
1434 use forward slashes throughout the configuration files.</p>
1439 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1440 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1443 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1444 <div class="directive-section"><h2><a name="ErrorLogFormat" id="ErrorLogFormat">ErrorLogFormat</a> <a name="errorlogformat" id="errorlogformat">Directive</a></h2>
1445 <table class="directive">
1446 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Format specification for error log entries</td></tr>
1447 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code> ErrorLogFormat [connection|request] <var>format</var></code></td></tr>
1448 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1449 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1450 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1452 <p><code class="directive">ErrorLogFormat</code> allows to specify what
1453 supplementary information is logged in the error log in addition to the
1454 actual log message.</p>
1456 <pre class="prettyprint lang-config">#Simple example
1457 ErrorLogFormat "[%t] [%l] [pid %P] %F: %E: [client %a] %M"</pre>
1460 <p>Specifying <code>connection</code> or <code>request</code> as first
1461 parameter allows to specify additional formats, causing additional
1462 information to be logged when the first message is logged for a specific
1463 connection or request, respectively. This additional information is only
1464 logged once per connection/request. If a connection or request is processed
1465 without causing any log message, the additional information is not logged
1468 <p>It can happen that some format string items do not produce output. For
1469 example, the Referer header is only present if the log message is
1470 associated to a request and the log message happens at a time when the
1471 Referer header has already been read from the client. If no output is
1472 produced, the default behavior is to delete everything from the preceding
1473 space character to the next space character. This means the log line is
1474 implicitly divided into fields on non-whitespace to whitespace transitions.
1475 If a format string item does not produce output, the whole field is
1476 omitted. For example, if the remote address <code>%a</code> in the log
1477 format <code>[%t] [%l] [%a] %M </code> is not available, the surrounding
1478 brackets are not logged either. Space characters can be escaped with a
1479 backslash to prevent them from delimiting a field. The combination '% '
1480 (percent space) is a zero-width field delimiter that does not produce any
1483 <p>The above behavior can be changed by adding modifiers to the format
1484 string item. A <code>-</code> (minus) modifier causes a minus to be logged if the
1485 respective item does not produce any output. In once-per-connection/request
1486 formats, it is also possible to use the <code>+</code> (plus) modifier. If an
1487 item with the plus modifier does not produce any output, the whole line is
1490 <p>A number as modifier can be used to assign a log severity level to a
1491 format item. The item will only be logged if the severity of the log
1492 message is not higher than the specified log severity level. The number can
1493 range from 1 (alert) over 4 (warn) and 7 (debug) to 15 (trace8).</p>
1495 <p>For example, here's what would happen if you added modifiers to
1496 the <code>%{Referer}i</code> token, which logs the
1497 <code>Referer</code> request header.</p>
1499 <table class="bordered"><tr class="header"><th>Modified Token</th><th>Meaning</th></tr>
1501 <td><code>%-{Referer}i</code></td>
1502 <td>Logs a <code>-</code> if <code>Referer</code> is not set.</td>
1505 <td><code>%+{Referer}i</code></td>
1506 <td>Omits the entire line if <code>Referer</code> is not set.</td>
1509 <td><code>%4{Referer}i</code></td>
1510 <td>Logs the <code>Referer</code> only if the log message severity
1511 is higher than 4.</td>
1515 <p>Some format string items accept additional parameters in braces.</p>
1517 <table class="bordered"><tr class="header"><th>Format String</th> <th>Description</th></tr>
1518 <tr><td><code>%%</code></td>
1519 <td>The percent sign</td></tr>
1520 <tr class="odd"><td><code>%a</code></td>
1521 <td>Client IP address and port of the request</td></tr>
1522 <tr><td><code>%{c}a</code></td>
1523 <td>Underlying peer IP address and port of the connection (see the
1524 <code class="module"><a href="../mod/mod_remoteip.html">mod_remoteip</a></code> module)</td></tr>
1525 <tr class="odd"><td><code>%A</code></td>
1526 <td>Local IP-address and port</td></tr>
1527 <tr><td><code>%{<em>name</em>}e</code></td>
1528 <td>Request environment variable <em>name</em></td></tr>
1529 <tr class="odd"><td><code>%E</code></td>
1530 <td>APR/OS error status code and string</td></tr>
1531 <tr><td><code>%F</code></td>
1532 <td>Source file name and line number of the log call</td></tr>
1533 <tr class="odd"><td><code>%{<em>name</em>}i</code></td>
1534 <td>Request header <em>name</em></td></tr>
1535 <tr><td><code>%k</code></td>
1536 <td>Number of keep-alive requests on this connection</td></tr>
1537 <tr class="odd"><td><code>%l</code></td>
1538 <td>Loglevel of the message</td></tr>
1539 <tr><td><code>%L</code></td>
1540 <td>Log ID of the request</td></tr>
1541 <tr class="odd"><td><code>%{c}L</code></td>
1542 <td>Log ID of the connection</td></tr>
1543 <tr><td><code>%{C}L</code></td>
1544 <td>Log ID of the connection if used in connection scope, empty otherwise</td></tr>
1545 <tr class="odd"><td><code>%m</code></td>
1546 <td>Name of the module logging the message</td></tr>
1547 <tr><td><code>%M</code></td>
1548 <td>The actual log message</td></tr>
1549 <tr class="odd"><td><code>%{<em>name</em>}n</code></td>
1550 <td>Request note <em>name</em></td></tr>
1551 <tr><td><code>%P</code></td>
1552 <td>Process ID of current process</td></tr>
1553 <tr class="odd"><td><code>%T</code></td>
1554 <td>Thread ID of current thread</td></tr>
1555 <tr><td><code>%{g}T</code></td>
1556 <td>System unique thread ID of current thread (the same ID as
1557 displayed by e.g. <code>top</code>; currently Linux only)</td></tr>
1558 <tr class="odd"><td><code>%t</code></td>
1559 <td>The current time</td></tr>
1560 <tr><td><code>%{u}t</code></td>
1561 <td>The current time including micro-seconds</td></tr>
1562 <tr class="odd"><td><code>%{cu}t</code></td>
1563 <td>The current time in compact ISO 8601 format, including
1564 micro-seconds</td></tr>
1565 <tr><td><code>%v</code></td>
1566 <td>The canonical <code class="directive"><a href="#servername">ServerName</a></code>
1567 of the current server.</td></tr>
1568 <tr class="odd"><td><code>%V</code></td>
1569 <td>The server name of the server serving the request according to the
1570 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code>
1572 <tr><td><code>\ </code> (backslash space)</td>
1573 <td>Non-field delimiting space</td></tr>
1574 <tr class="odd"><td><code>% </code> (percent space)</td>
1575 <td>Field delimiter (no output)</td></tr>
1578 <p>The log ID format <code>%L</code> produces a unique id for a connection
1579 or request. This can be used to correlate which log lines belong to the
1580 same connection or request, which request happens on which connection.
1581 A <code>%L</code> format string is also available in
1582 <code class="module"><a href="../mod/mod_log_config.html">mod_log_config</a></code>, to allow to correlate access log entries
1583 with error log lines. If <code class="module"><a href="../mod/mod_unique_id.html">mod_unique_id</a></code> is loaded, its
1584 unique id will be used as log ID for requests.</p>
1586 <pre class="prettyprint lang-config">#Example (default format for threaded MPMs)
1587 ErrorLogFormat "[%{u}t] [%-m:%l] [pid %P:tid %T] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"</pre>
1590 <p>This would result in error messages such as:</p>
1592 <div class="example"><p><code>
1593 [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
1596 <p>Notice that, as discussed above, some fields are omitted
1597 entirely because they are not defined.</p>
1599 <pre class="prettyprint lang-config">#Example (similar to the 2.2.x format)
1600 ErrorLogFormat "[%t] [%l] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"</pre>
1603 <pre class="prettyprint lang-config">#Advanced example with request/connection log IDs
1604 ErrorLogFormat "[%{uc}t] [%-m:%-l] [R:%L] [C:%{C}L] %7F: %E: %M"
1605 ErrorLogFormat request "[%{uc}t] [R:%L] Request %k on C:%{c}L pid:%P tid:%T"
1606 ErrorLogFormat request "[%{uc}t] [R:%L] UA:'%+{User-Agent}i'"
1607 ErrorLogFormat request "[%{uc}t] [R:%L] Referer:'%+{Referer}i'"
1608 ErrorLogFormat connection "[%{uc}t] [C:%{c}L] local\ %a remote\ %A"</pre>
1614 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
1615 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1616 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1619 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1620 <div class="directive-section"><h2><a name="ExtendedStatus" id="ExtendedStatus">ExtendedStatus</a> <a name="extendedstatus" id="extendedstatus">Directive</a></h2>
1621 <table class="directive">
1622 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Keep track of extended status information for each
1624 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ExtendedStatus On|Off</code></td></tr>
1625 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ExtendedStatus Off[*]</code></td></tr>
1626 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
1627 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1628 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1630 <p>This option tracks additional data per worker about the
1631 currently executing request, and a utilization summary; you
1632 can see these variables during runtime by configuring
1633 <code class="module"><a href="../mod/mod_status.html">mod_status</a></code>. Note that other modules may
1634 rely on this scoreboard.</p>
1636 <p>This setting applies to the entire server, and cannot be
1637 enabled or disabled on a virtualhost-by-virtualhost basis.
1638 The collection of extended status information can slow down
1639 the server. Also note that this setting cannot be changed
1640 during a graceful restart.</p>
1643 <p>Note that loading <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> will change
1644 the default behavior to ExtendedStatus On, while other
1645 third party modules may do the same. Such modules rely on
1646 collecting detailed information about the state of all workers.
1647 The default is changed by <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> beginning
1648 with version 2.3.6; the previous default was always Off.</p>
1653 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1654 <div class="directive-section"><h2><a name="FileETag" id="FileETag">FileETag</a> <a name="fileetag" id="fileetag">Directive</a></h2>
1655 <table class="directive">
1656 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>File attributes used to create the ETag
1657 HTTP response header for static files</td></tr>
1658 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>FileETag <var>component</var> ...</code></td></tr>
1659 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>FileETag MTime Size</code></td></tr>
1660 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1661 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1662 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1663 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1664 <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
1668 The <code class="directive">FileETag</code> directive configures the file
1669 attributes that are used to create the <code>ETag</code> (entity
1670 tag) response header field when the document is based on a static file.
1671 (The <code>ETag</code> value is used in cache management to save
1672 network bandwidth.) The
1673 <code class="directive">FileETag</code> directive allows you to choose
1674 which of these -- if any -- should be used. The recognized keywords are:
1678 <dt><strong>INode</strong></dt>
1679 <dd>The file's i-node number will be included in the calculation</dd>
1680 <dt><strong>MTime</strong></dt>
1681 <dd>The date and time the file was last modified will be included</dd>
1682 <dt><strong>Size</strong></dt>
1683 <dd>The number of bytes in the file will be included</dd>
1684 <dt><strong>All</strong></dt>
1685 <dd>All available fields will be used. This is equivalent to:
1686 <pre class="prettyprint lang-config">FileETag INode MTime Size</pre>
1688 <dt><strong>None</strong></dt>
1689 <dd>If a document is file-based, no <code>ETag</code> field will be
1690 included in the response</dd>
1693 <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
1694 keywords may be prefixed with either <code>+</code> or <code>-</code>,
1695 which allow changes to be made to the default setting inherited
1696 from a broader scope. Any keyword appearing without such a prefix
1697 immediately and completely cancels the inherited setting.</p>
1699 <p>If a directory's configuration includes
1700 <code>FileETag INode MTime Size</code>, and a
1701 subdirectory's includes <code>FileETag -INode</code>,
1702 the setting for that subdirectory (which will be inherited by
1703 any sub-subdirectories that don't override it) will be equivalent to
1704 <code>FileETag MTime Size</code>.</p>
1705 <div class="warning"><h3>Warning</h3>
1706 Do not change the default for directories or locations that have WebDAV
1707 enabled and use <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> as a storage provider.
1708 <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> uses <code>MTime Size</code>
1709 as a fixed format for <code>ETag</code> comparisons on conditional requests.
1710 These conditional requests will break if the <code>ETag</code> format is
1711 changed via <code class="directive">FileETag</code>.
1713 <div class="note"><h3>Server Side Includes</h3>
1714 An ETag is not generated for responses parsed by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>,
1715 since the response entity can change without a change of the INode, MTime, or Size
1716 of the static file with embedded SSI directives.
1721 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1722 <div class="directive-section"><h2><a name="Files" id="Files"><Files></a> <a name="files" id="files">Directive</a></h2>
1723 <table class="directive">
1724 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to matched
1726 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Files <var>filename</var>> ... </Files></code></td></tr>
1727 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1728 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1729 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1730 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1732 <p>The <code class="directive"><Files></code> directive
1733 limits the scope of the enclosed directives by filename. It is comparable
1734 to the <code class="directive"><a href="#directory"><Directory></a></code>
1735 and <code class="directive"><a href="#location"><Location></a></code>
1736 directives. It should be matched with a <code></Files></code>
1737 directive. The directives given within this section will be applied to
1738 any object with a basename (last component of filename) matching the
1739 specified filename. <code class="directive"><Files></code>
1740 sections are processed in the order they appear in the
1741 configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
1742 <code>.htaccess</code> files are read, but before <code class="directive"><a href="#location"><Location></a></code> sections. Note
1743 that <code class="directive"><Files></code> can be nested
1744 inside <code class="directive"><a href="#directory"><Directory></a></code> sections to restrict the
1745 portion of the filesystem they apply to.</p>
1747 <p>The <var>filename</var> argument should include a filename, or
1748 a wild-card string, where <code>?</code> matches any single character,
1749 and <code>*</code> matches any sequences of characters.</p>
1750 <pre class="prettyprint lang-config"><Files "cat.html">
1751 # Insert stuff that applies to cat.html here
1754 <Files "?at.*">
1755 # This would apply to cat.html, bat.html, hat.php and so on.
1756 </Files></pre>
1758 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
1759 can also be used, with the addition of the
1760 <code>~</code> character. For example:</p>
1762 <pre class="prettyprint lang-config"><Files ~ "\.(gif|jpe?g|png)$">
1764 </Files></pre>
1767 <p>would match most common Internet graphics formats. <code class="directive"><a href="#filesmatch"><FilesMatch></a></code> is preferred,
1770 <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
1771 <code>.htaccess</code> files. This allows users to control access to
1772 their own files, at a file-by-file level.</p>
1777 <li><a href="../sections.html">How <Directory>, <Location>
1778 and <Files> sections work</a> for an explanation of how these
1779 different sections are combined when a request is received</li>
1782 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1783 <div class="directive-section"><h2><a name="FilesMatch" id="FilesMatch"><FilesMatch></a> <a name="filesmatch" id="filesmatch">Directive</a></h2>
1784 <table class="directive">
1785 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to regular-expression matched
1787 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><FilesMatch <var>regex</var>> ... </FilesMatch></code></td></tr>
1788 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1789 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1790 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1791 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1793 <p>The <code class="directive"><FilesMatch></code> directive
1794 limits the scope of the enclosed directives by filename, just as the
1795 <code class="directive"><a href="#files"><Files></a></code> directive
1796 does. However, it accepts a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular
1797 expression</a>. For example:</p>
1799 <pre class="prettyprint lang-config"><FilesMatch "\.(gif|jpe?g|png)$">
1801 </FilesMatch></pre>
1804 <p>would match most common Internet graphics formats.</p>
1806 <p>From 2.4.8 onwards, named groups and backreferences are captured and
1807 written to the environment with the corresponding name prefixed with
1808 "MATCH_" and in upper case. This allows elements of files to be referenced
1809 from within <a href="../expr.html">expressions</a> and modules like
1810 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
1811 (unnamed) backreferences are ignored. Use named groups instead.</p>
1813 <pre class="prettyprint lang-config"><FilesMatch ^(?<sitename>[^/]+)>
1814 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
1815 </FilesMatch></pre>
1820 <li><a href="../sections.html">How <Directory>, <Location>
1821 and <Files> sections work</a> for an explanation of how these
1822 different sections are combined when a request is received</li>
1825 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1826 <div class="directive-section"><h2><a name="ForceType" id="ForceType">ForceType</a> <a name="forcetype" id="forcetype">Directive</a></h2>
1827 <table class="directive">
1828 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be served with the specified
1829 media type in the HTTP Content-Type header field</td></tr>
1830 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ForceType <var>media-type</var>|None</code></td></tr>
1831 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
1832 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1833 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1834 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1836 <p>When placed into an <code>.htaccess</code> file or a
1837 <code class="directive"><a href="#directory"><Directory></a></code>, or
1838 <code class="directive"><a href="#location"><Location></a></code> or
1839 <code class="directive"><a href="#files"><Files></a></code>
1840 section, this directive forces all matching files to be served
1841 with the content type identification given by
1842 <var>media-type</var>. For example, if you had a directory full of
1843 GIF files, but did not want to label them all with <code>.gif</code>,
1844 you might want to use:</p>
1846 <pre class="prettyprint lang-config">ForceType image/gif</pre>
1849 <p>Note that this directive overrides other indirect media type
1850 associations defined in mime.types or via the
1851 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code>.</p>
1853 <p>You can also override more general
1854 <code class="directive">ForceType</code> settings
1855 by using the value of <code>None</code>:</p>
1857 <pre class="prettyprint lang-config"># force all files to be image/gif:
1858 <Location /images>
1862 # but normal mime-type associations here:
1863 <Location /images/mixed>
1865 </Location></pre>
1868 <p>This directive primarily overrides the content types generated for
1869 static files served out of the filesystem. For resources other than
1870 static files, where the generator of the response typically specifies
1871 a Content-Type, this directive has no effect.</p>
1875 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1876 <div class="directive-section"><h2><a name="GprofDir" id="GprofDir">GprofDir</a> <a name="gprofdir" id="gprofdir">Directive</a></h2>
1877 <table class="directive">
1878 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory to write gmon.out profiling data to. </td></tr>
1879 <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>
1880 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1881 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1882 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1884 <p>When the server has been compiled with gprof profiling support,
1885 <code class="directive">GprofDir</code> causes <code>gmon.out</code> files to
1886 be written to the specified directory when the process exits. If the
1887 argument ends with a percent symbol ('%'), subdirectories are created
1888 for each process id.</p>
1890 <p>This directive currently only works with the <code class="module"><a href="../mod/prefork.html">prefork</a></code>
1894 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1895 <div class="directive-section"><h2><a name="HostnameLookups" id="HostnameLookups">HostnameLookups</a> <a name="hostnamelookups" id="hostnamelookups">Directive</a></h2>
1896 <table class="directive">
1897 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables DNS lookups on client IP addresses</td></tr>
1898 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>HostnameLookups On|Off|Double</code></td></tr>
1899 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>HostnameLookups Off</code></td></tr>
1900 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1901 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1902 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1904 <p>This directive enables DNS lookups so that host names can be
1905 logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
1906 The value <code>Double</code> refers to doing double-reverse
1907 DNS lookup. That is, after a reverse lookup is performed, a forward
1908 lookup is then performed on that result. At least one of the IP
1909 addresses in the forward lookup must match the original
1910 address. (In "tcpwrappers" terminology this is called
1911 <code>PARANOID</code>.)</p>
1913 <p>Regardless of the setting, when <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code> is
1914 used for controlling access by hostname, a double reverse lookup
1915 will be performed. This is necessary for security. Note that the
1916 result of this double-reverse isn't generally available unless you
1917 set <code>HostnameLookups Double</code>. For example, if only
1918 <code>HostnameLookups On</code> and a request is made to an object
1919 that is protected by hostname restrictions, regardless of whether
1920 the double-reverse fails or not, CGIs will still be passed the
1921 single-reverse result in <code>REMOTE_HOST</code>.</p>
1923 <p>The default is <code>Off</code> in order to save the network
1924 traffic for those sites that don't truly need the reverse
1925 lookups done. It is also better for the end users because they
1926 don't have to suffer the extra latency that a lookup entails.
1927 Heavily loaded sites should leave this directive
1928 <code>Off</code>, since DNS lookups can take considerable
1929 amounts of time. The utility <code class="program"><a href="../programs/logresolve.html">logresolve</a></code>, compiled by
1930 default to the <code>bin</code> subdirectory of your installation
1931 directory, can be used to look up host names from logged IP addresses
1934 <p>Finally, if you have <a href="mod_authz_host.html#reqhost">hostname-based Require
1935 directives</a>, a hostname lookup will be performed regardless of
1936 the setting of <code>HostnameLookups</code>.</p>
1939 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1940 <div class="directive-section"><h2><a name="If" id="If"><If></a> <a name="if" id="if">Directive</a></h2>
1941 <table class="directive">
1942 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is
1943 satisfied by a request at runtime</td></tr>
1944 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><If <var>expression</var>> ... </If></code></td></tr>
1945 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1946 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1947 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1948 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1950 <p>The <code class="directive"><If></code> directive
1951 evaluates an expression at runtime, and applies the enclosed
1952 directives if and only if the expression evaluates to true.
1955 <pre class="prettyprint lang-config"><If "-z req('Host')"></pre>
1958 <p>would match HTTP/1.0 requests without a <var>Host:</var> header.
1959 Expressions may contain various shell-like operators for string
1960 comparison (<code>==</code>, <code>!=</code>, <code><</code>, ...),
1961 integer comparison (<code>-eq</code>, <code>-ne</code>, ...),
1962 and others (<code>-n</code>, <code>-z</code>, <code>-f</code>, ...).
1963 It is also possible to use regular expressions, </p>
1965 <pre class="prettyprint lang-config"><If "%{QUERY_STRING} =~ /(delete|commit)=.*?elem/"></pre>
1968 <p>shell-like pattern matches and many other operations. These operations
1969 can be done on request headers (<code>req</code>), environment variables
1970 (<code>env</code>), and a large number of other properties. The full
1971 documentation is available in <a href="../expr.html">Expressions in
1972 Apache HTTP Server</a>.</p>
1974 <p>Only directives that support the <a href="directive-dict.html#Context">directory context</a> can be used within this configuration section.</p>
1979 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
1980 for a complete reference and more examples.</li>
1981 <li><code class="directive"><a href="#elseif"><ElseIf></a></code></li>
1982 <li><code class="directive"><a href="#else"><Else></a></code></li>
1983 <li><a href="../sections.html">How <Directory>, <Location>,
1984 <Files> sections work</a> for an explanation of how these
1985 different sections are combined when a request is received.
1986 <code class="directive"><If></code>,
1987 <code class="directive"><ElseIf></code>, and
1988 <code class="directive"><Else></code> are applied last.</li>
1991 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1992 <div class="directive-section"><h2><a name="IfDefine" id="IfDefine"><IfDefine></a> <a name="ifdefine" id="ifdefine">Directive</a></h2>
1993 <table class="directive">
1994 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that will be processed only
1995 if a test is true at startup</td></tr>
1996 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfDefine [!]<var>parameter-name</var>> ...
1997 </IfDefine></code></td></tr>
1998 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1999 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2000 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2001 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2003 <p>The <code><IfDefine <var>test</var>>...</IfDefine>
2004 </code> section is used to mark directives that are conditional. The
2005 directives within an <code class="directive"><IfDefine></code>
2006 section are only processed if the <var>test</var> is true. If <var>
2007 test</var> is false, everything between the start and end markers is
2010 <p>The <var>test</var> in the <code class="directive"><IfDefine></code> section directive can be one of two forms:</p>
2013 <li><var>parameter-name</var></li>
2015 <li><code>!</code><var>parameter-name</var></li>
2018 <p>In the former case, the directives between the start and end
2019 markers are only processed if the parameter named
2020 <var>parameter-name</var> is defined. The second format reverses
2021 the test, and only processes the directives if
2022 <var>parameter-name</var> is <strong>not</strong> defined.</p>
2024 <p>The <var>parameter-name</var> argument is a define as given on the
2025 <code class="program"><a href="../programs/httpd.html">httpd</a></code> command line via <code>-D<var>parameter</var>
2026 </code> at the time the server was started or by the <code class="directive"><a href="#define">Define</a></code> directive.</p>
2028 <p><code class="directive"><IfDefine></code> sections are
2029 nest-able, which can be used to implement simple
2030 multiple-parameter tests. Example:</p>
2032 <div class="example"><p><code>httpd -DReverseProxy -DUseCache -DMemCache ...</code></p></div>
2033 <pre class="prettyprint lang-config"><IfDefine ReverseProxy>
2034 LoadModule proxy_module modules/mod_proxy.so
2035 LoadModule proxy_http_module modules/mod_proxy_http.so
2036 <IfDefine UseCache>
2037 LoadModule cache_module modules/mod_cache.so
2038 <IfDefine MemCache>
2039 LoadModule mem_cache_module modules/mod_mem_cache.so
2041 <IfDefine !MemCache>
2042 LoadModule cache_disk_module modules/mod_cache_disk.so
2045 </IfDefine></pre>
2049 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2050 <div class="directive-section"><h2><a name="IfModule" id="IfModule"><IfModule></a> <a name="ifmodule" id="ifmodule">Directive</a></h2>
2051 <table class="directive">
2052 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that are processed conditional on the
2053 presence or absence of a specific module</td></tr>
2054 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfModule [!]<var>module-file</var>|<var>module-identifier</var>> ...
2055 </IfModule></code></td></tr>
2056 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2057 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2058 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2059 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2061 <p>The <code><IfModule <var>test</var>>...</IfModule></code>
2062 section is used to mark directives that are conditional on the presence of
2063 a specific module. The directives within an <code class="directive"><IfModule></code> section are only processed if the <var>test</var>
2064 is true. If <var>test</var> is false, everything between the start and
2065 end markers is ignored.</p>
2067 <p>The <var>test</var> in the <code class="directive"><IfModule></code> section directive can be one of two forms:</p>
2070 <li><var>module</var></li>
2072 <li>!<var>module</var></li>
2075 <p>In the former case, the directives between the start and end
2076 markers are only processed if the module named <var>module</var>
2077 is included in Apache httpd -- either compiled in or
2078 dynamically loaded using <code class="directive"><a href="../mod/mod_so.html#loadmodule">LoadModule</a></code>. The second format reverses the test,
2079 and only processes the directives if <var>module</var> is
2080 <strong>not</strong> included.</p>
2082 <p>The <var>module</var> argument can be either the module identifier or
2083 the file name of the module, at the time it was compiled. For example,
2084 <code>rewrite_module</code> is the identifier and
2085 <code>mod_rewrite.c</code> is the file name. If a module consists of
2086 several source files, use the name of the file containing the string
2087 <code>STANDARD20_MODULE_STUFF</code>.</p>
2089 <p><code class="directive"><IfModule></code> sections are
2090 nest-able, which can be used to implement simple multiple-module
2093 <div class="note">This section should only be used if you need to have one
2094 configuration file that works whether or not a specific module
2095 is available. In normal operation, directives need not be
2096 placed in <code class="directive"><IfModule></code>
2100 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2101 <div class="directive-section"><h2><a name="Include" id="Include">Include</a> <a name="include" id="include">Directive</a></h2>
2102 <table class="directive">
2103 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2104 the server configuration files</td></tr>
2105 <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>
2106 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2107 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2108 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2109 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Directory
2110 wildcard matching available in 2.3.6 and later</td></tr>
2112 <p>This directive allows inclusion of other configuration files
2113 from within the server configuration files.</p>
2115 <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used
2116 in the filename or directory parts of the path to include several files
2117 at once, in alphabetical order. In addition, if
2118 <code class="directive">Include</code> points to a directory, rather than a file,
2119 Apache httpd will read all files in that directory and any subdirectory.
2120 However, including entire directories is not recommended, because it is
2121 easy to accidentally leave temporary files in a directory that can cause
2122 <code class="program"><a href="../programs/httpd.html">httpd</a></code> to fail. Instead, we encourage you to use the
2123 wildcard syntax shown below, to include files that match a particular
2124 pattern, such as *.conf, for example.</p>
2126 <p>The <code class="directive"><a href="#include">Include</a></code> directive will
2127 <strong>fail with an error</strong> if a wildcard expression does not
2128 match any file. The <code class="directive"><a href="#includeoptional">IncludeOptional</a></code>
2129 directive can be used if non-matching wildcards should be ignored.</p>
2131 <p>The file path specified may be an absolute path, or may be relative
2132 to the <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory.</p>
2136 <pre class="prettyprint lang-config">Include /usr/local/apache2/conf/ssl.conf
2137 Include /usr/local/apache2/conf/vhosts/*.conf</pre>
2140 <p>Or, providing paths relative to your <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory:</p>
2142 <pre class="prettyprint lang-config">Include conf/ssl.conf
2143 Include conf/vhosts/*.conf</pre>
2146 <p>Wildcards may be included in the directory or file portion of the
2147 path. This example will fail if there is no subdirectory in conf/vhosts
2148 that contains at least one *.conf file:</p>
2150 <pre class="prettyprint lang-config">Include conf/vhosts/*/*.conf</pre>
2153 <p>Alternatively, the following command will just be ignored in case of
2154 missing files or directories:</p>
2156 <pre class="prettyprint lang-config">IncludeOptional conf/vhosts/*/*.conf</pre>
2162 <li><code class="directive"><a href="#includeoptional">IncludeOptional</a></code></li>
2163 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2166 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2167 <div class="directive-section"><h2><a name="IncludeOptional" id="IncludeOptional">IncludeOptional</a> <a name="includeoptional" id="includeoptional">Directive</a></h2>
2168 <table class="directive">
2169 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2170 the server configuration files</td></tr>
2171 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>IncludeOptional <var>file-path</var>|<var>directory-path</var>|<var>wildcard</var></code></td></tr>
2172 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2173 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2174 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2175 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in 2.3.6 and later</td></tr>
2177 <p>This directive allows inclusion of other configuration files
2178 from within the server configuration files. It works identically to the
2179 <code class="directive"><a href="#include">Include</a></code> directive, with the
2180 exception that if wildcards do not match any file or directory, the
2181 <code class="directive"><a href="#includeoptional">IncludeOptional</a></code> directive will be
2182 silently ignored instead of causing an error.</p>
2186 <li><code class="directive"><a href="#include">Include</a></code></li>
2187 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2190 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2191 <div class="directive-section"><h2><a name="KeepAlive" id="KeepAlive">KeepAlive</a> <a name="keepalive" id="keepalive">Directive</a></h2>
2192 <table class="directive">
2193 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables HTTP persistent connections</td></tr>
2194 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAlive On|Off</code></td></tr>
2195 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAlive On</code></td></tr>
2196 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2197 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2198 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2200 <p>The Keep-Alive extension to HTTP/1.0 and the persistent
2201 connection feature of HTTP/1.1 provide long-lived HTTP sessions
2202 which allow multiple requests to be sent over the same TCP
2203 connection. In some cases this has been shown to result in an
2204 almost 50% speedup in latency times for HTML documents with
2205 many images. To enable Keep-Alive connections, set
2206 <code>KeepAlive On</code>.</p>
2208 <p>For HTTP/1.0 clients, Keep-Alive connections will only be
2209 used if they are specifically requested by a client. In
2210 addition, a Keep-Alive connection with an HTTP/1.0 client can
2211 only be used when the length of the content is known in
2212 advance. This implies that dynamic content such as CGI output,
2213 SSI pages, and server-generated directory listings will
2214 generally not use Keep-Alive connections to HTTP/1.0 clients.
2215 For HTTP/1.1 clients, persistent connections are the default
2216 unless otherwise specified. If the client requests it, chunked
2217 encoding will be used in order to send content of unknown
2218 length over persistent connections.</p>
2220 <p>When a client uses a Keep-Alive connection it will be counted
2221 as a single "request" for the <code class="directive"><a href="../mod/mpm_common.html#maxconnectionsperchild">MaxConnectionsPerChild</a></code> directive, regardless
2222 of how many requests are sent using the connection.</p>
2226 <li><code class="directive"><a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></code></li>
2229 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2230 <div class="directive-section"><h2><a name="KeepAliveTimeout" id="KeepAliveTimeout">KeepAliveTimeout</a> <a name="keepalivetimeout" id="keepalivetimeout">Directive</a></h2>
2231 <table class="directive">
2232 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for subsequent
2233 requests on a persistent connection</td></tr>
2234 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAliveTimeout <var>num</var>[ms]</code></td></tr>
2235 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAliveTimeout 5</code></td></tr>
2236 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2237 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2238 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2240 <p>The number of seconds Apache httpd will wait for a subsequent
2241 request before closing the connection. By adding a postfix of ms the
2242 timeout can be also set in milliseconds. Once a request has been
2243 received, the timeout value specified by the
2244 <code class="directive"><a href="#timeout">Timeout</a></code> directive applies.</p>
2246 <p>Setting <code class="directive">KeepAliveTimeout</code> to a high value
2247 may cause performance problems in heavily loaded servers. The
2248 higher the timeout, the more server processes will be kept
2249 occupied waiting on connections with idle clients.</p>
2251 <p>In a name-based virtual host context, the value of the first
2252 defined virtual host best matching the local IP and port will be used.</p>
2255 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2256 <div class="directive-section"><h2><a name="Limit" id="Limit"><Limit></a> <a name="limit" id="limit">Directive</a></h2>
2257 <table class="directive">
2258 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict enclosed access controls to only certain HTTP
2260 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Limit <var>method</var> [<var>method</var>] ... > ...
2261 </Limit></code></td></tr>
2262 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2263 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2264 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2265 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2267 <p>Access controls are normally effective for
2268 <strong>all</strong> access methods, and this is the usual
2269 desired behavior. <strong>In the general case, access control
2270 directives should not be placed within a
2271 <code class="directive"><Limit></code> section.</strong></p>
2273 <p>The purpose of the <code class="directive"><Limit></code>
2274 directive is to restrict the effect of the access controls to the
2275 nominated HTTP methods. For all other methods, the access
2276 restrictions that are enclosed in the <code class="directive"><Limit></code> bracket <strong>will have no
2277 effect</strong>. The following example applies the access control
2278 only to the methods <code>POST</code>, <code>PUT</code>, and
2279 <code>DELETE</code>, leaving all other methods unprotected:</p>
2281 <pre class="prettyprint lang-config"><Limit POST PUT DELETE>
2283 </Limit></pre>
2286 <p>The method names listed can be one or more of: <code>GET</code>,
2287 <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
2288 <code>CONNECT</code>, <code>OPTIONS</code>,
2289 <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
2290 <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
2291 <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
2292 case-sensitive.</strong> If <code>GET</code> is used it will also
2293 restrict <code>HEAD</code> requests. The <code>TRACE</code> method
2294 cannot be limited (see <code class="directive"><a href="#traceenable">TraceEnable</a></code>).</p>
2296 <div class="warning">A <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section should always be
2297 used in preference to a <code class="directive"><Limit></code>
2298 section when restricting access, since a <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section provides protection
2299 against arbitrary methods.</div>
2301 <p>The <code class="directive"><Limit></code> and
2302 <code class="directive"><a href="#limitexcept"><LimitExcept></a></code>
2303 directives may be nested. In this case, each successive level of
2304 <code class="directive"><Limit></code> or <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> directives must
2305 further restrict the set of methods to which access controls apply.</p>
2307 <div class="warning">When using
2308 <code class="directive"><Limit></code> or
2309 <code class="directive"><LimitExcept></code> directives with
2310 the <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directive,
2311 note that the first <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code>
2312 to succeed authorizes the request, regardless of the presence of other
2313 <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directives.</div>
2315 <p>For example, given the following configuration, all users will
2316 be authorized for <code>POST</code> requests, and the
2317 <code>Require group editors</code> directive will be ignored
2320 <pre class="prettyprint lang-config"><LimitExcept GET>
2322 </LimitExcept>
2324 Require group editors
2325 </Limit></pre>
2329 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2330 <div class="directive-section"><h2><a name="LimitExcept" id="LimitExcept"><LimitExcept></a> <a name="limitexcept" id="limitexcept">Directive</a></h2>
2331 <table class="directive">
2332 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict access controls to all HTTP methods
2333 except the named ones</td></tr>
2334 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LimitExcept <var>method</var> [<var>method</var>] ... > ...
2335 </LimitExcept></code></td></tr>
2336 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2337 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2338 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2339 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2341 <p><code class="directive"><LimitExcept></code> and
2342 <code></LimitExcept></code> are used to enclose
2343 a group of access control directives which will then apply to any
2344 HTTP access method <strong>not</strong> listed in the arguments;
2345 i.e., it is the opposite of a <code class="directive"><a href="#limit"><Limit></a></code> section and can be used to control
2346 both standard and nonstandard/unrecognized methods. See the
2347 documentation for <code class="directive"><a href="#limit"><Limit></a></code> for more details.</p>
2351 <pre class="prettyprint lang-config"><LimitExcept POST GET>
2353 </LimitExcept></pre>
2358 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2359 <div class="directive-section"><h2><a name="LimitInternalRecursion" id="LimitInternalRecursion">LimitInternalRecursion</a> <a name="limitinternalrecursion" id="limitinternalrecursion">Directive</a></h2>
2360 <table class="directive">
2361 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine maximum number of internal redirects and nested
2362 subrequests</td></tr>
2363 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitInternalRecursion <var>number</var> [<var>number</var>]</code></td></tr>
2364 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitInternalRecursion 10</code></td></tr>
2365 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2366 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2367 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2369 <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
2370 redirects the original request to a CGI script. A subrequest is Apache httpd's
2371 mechanism to find out what would happen for some URI if it were requested.
2372 For example, <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> uses subrequests to look for the
2373 files listed in the <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
2376 <p><code class="directive">LimitInternalRecursion</code> prevents the server
2377 from crashing when entering an infinite loop of internal redirects or
2378 subrequests. Such loops are usually caused by misconfigurations.</p>
2380 <p>The directive stores two different limits, which are evaluated on
2381 per-request basis. The first <var>number</var> is the maximum number of
2382 internal redirects, that may follow each other. The second <var>number</var>
2383 determines, how deep subrequests may be nested. If you specify only one
2384 <var>number</var>, it will be assigned to both limits.</p>
2386 <pre class="prettyprint lang-config">LimitInternalRecursion 5</pre>
2390 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2391 <div class="directive-section"><h2><a name="LimitRequestBody" id="LimitRequestBody">LimitRequestBody</a> <a name="limitrequestbody" id="limitrequestbody">Directive</a></h2>
2392 <table class="directive">
2393 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restricts the total size of the HTTP request body sent
2394 from the client</td></tr>
2395 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestBody <var>bytes</var></code></td></tr>
2396 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestBody 0</code></td></tr>
2397 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2398 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2399 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2400 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2402 <p>This directive specifies the number of <var>bytes</var> from 0
2403 (meaning unlimited) to 2147483647 (2GB) that are allowed in a
2404 request body. See the note below for the limited applicability
2405 to proxy requests.</p>
2407 <p>The <code class="directive">LimitRequestBody</code> directive allows
2408 the user to set a limit on the allowed size of an HTTP request
2409 message body within the context in which the directive is given
2410 (server, per-directory, per-file or per-location). If the client
2411 request exceeds that limit, the server will return an error
2412 response instead of servicing the request. The size of a normal
2413 request message body will vary greatly depending on the nature of
2414 the resource and the methods allowed on that resource. CGI scripts
2415 typically use the message body for retrieving form information.
2416 Implementations of the <code>PUT</code> method will require
2417 a value at least as large as any representation that the server
2418 wishes to accept for that resource.</p>
2420 <p>This directive gives the server administrator greater
2421 control over abnormal client request behavior, which may be
2422 useful for avoiding some forms of denial-of-service
2425 <p>If, for example, you are permitting file upload to a particular
2426 location, and wish to limit the size of the uploaded file to 100K,
2427 you might use the following directive:</p>
2429 <pre class="prettyprint lang-config">LimitRequestBody 102400</pre>
2432 <div class="note"><p>For a full description of how this directive is interpreted by
2433 proxy requests, see the <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> documentation.</p>
2438 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2439 <div class="directive-section"><h2><a name="LimitRequestFields" id="LimitRequestFields">LimitRequestFields</a> <a name="limitrequestfields" id="limitrequestfields">Directive</a></h2>
2440 <table class="directive">
2441 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of HTTP request header fields that
2442 will be accepted from the client</td></tr>
2443 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFields <var>number</var></code></td></tr>
2444 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFields 100</code></td></tr>
2445 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2446 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2447 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2449 <p><var>Number</var> is an integer from 0 (meaning unlimited) to
2450 32767. The default value is defined by the compile-time
2451 constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
2454 <p>The <code class="directive">LimitRequestFields</code> directive allows
2455 the server administrator to modify the limit on the number of
2456 request header fields allowed in an HTTP request. A server needs
2457 this value to be larger than the number of fields that a normal
2458 client request might include. The number of request header fields
2459 used by a client rarely exceeds 20, but this may vary among
2460 different client implementations, often depending upon the extent
2461 to which a user has configured their browser to support detailed
2462 content negotiation. Optional HTTP extensions are often expressed
2463 using request header fields.</p>
2465 <p>This directive gives the server administrator greater
2466 control over abnormal client request behavior, which may be
2467 useful for avoiding some forms of denial-of-service attacks.
2468 The value should be increased if normal clients see an error
2469 response from the server that indicates too many fields were
2470 sent in the request.</p>
2474 <pre class="prettyprint lang-config">LimitRequestFields 50</pre>
2477 <div class="warning"><h3>Warning</h3>
2478 <p> When name-based virtual hosting is used, the value for this
2479 directive is taken from the default (first-listed) virtual host for the
2480 local IP and port combination.</p>
2485 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2486 <div class="directive-section"><h2><a name="LimitRequestFieldSize" id="LimitRequestFieldSize">LimitRequestFieldSize</a> <a name="limitrequestfieldsize" id="limitrequestfieldsize">Directive</a></h2>
2487 <table class="directive">
2488 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of the HTTP request header allowed from the
2490 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFieldSize <var>bytes</var></code></td></tr>
2491 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFieldSize 8190</code></td></tr>
2492 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2493 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2494 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2496 <p>This directive specifies the number of <var>bytes</var>
2497 that will be allowed in an HTTP request header.</p>
2499 <p>The <code class="directive">LimitRequestFieldSize</code> directive
2500 allows the server administrator to set the limit
2501 on the allowed size of an HTTP request header field. A server
2502 needs this value to be large enough to hold any one header field
2503 from a normal client request. The size of a normal request header
2504 field will vary greatly among different client implementations,
2505 often depending upon the extent to which a user has configured
2506 their browser to support detailed content negotiation. SPNEGO
2507 authentication headers can be up to 12392 bytes.</p>
2509 <p>This directive gives the server administrator greater
2510 control over abnormal client request behavior, which may be
2511 useful for avoiding some forms of denial-of-service attacks.</p>
2515 <pre class="prettyprint lang-config">LimitRequestFieldSize 4094</pre>
2518 <div class="note">Under normal conditions, the value should not be changed from
2521 <div class="warning"><h3>Warning</h3>
2522 <p> When name-based virtual hosting is used, the value for this
2523 directive is taken from the default (first-listed) virtual host best
2524 matching the current IP address and port combination.</p>
2528 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2529 <div class="directive-section"><h2><a name="LimitRequestLine" id="LimitRequestLine">LimitRequestLine</a> <a name="limitrequestline" id="limitrequestline">Directive</a></h2>
2530 <table class="directive">
2531 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limit the size of the HTTP request line that will be accepted
2532 from the client</td></tr>
2533 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestLine <var>bytes</var></code></td></tr>
2534 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestLine 8190</code></td></tr>
2535 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2536 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2537 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2539 <p>This directive sets the number of <var>bytes</var> that will be
2540 allowed on the HTTP request-line.</p>
2542 <p>The <code class="directive">LimitRequestLine</code> directive allows
2543 the server administrator to set the limit on the allowed size
2544 of a client's HTTP request-line. Since the request-line consists of the
2545 HTTP method, URI, and protocol version, the
2546 <code class="directive">LimitRequestLine</code> directive places a
2547 restriction on the length of a request-URI allowed for a request
2548 on the server. A server needs this value to be large enough to
2549 hold any of its resource names, including any information that
2550 might be passed in the query part of a <code>GET</code> request.</p>
2552 <p>This directive gives the server administrator greater
2553 control over abnormal client request behavior, which may be
2554 useful for avoiding some forms of denial-of-service attacks.</p>
2558 <pre class="prettyprint lang-config">LimitRequestLine 4094</pre>
2561 <div class="note">Under normal conditions, the value should not be changed from
2564 <div class="warning"><h3>Warning</h3>
2565 <p> When name-based virtual hosting is used, the value for this
2566 directive is taken from the default (first-listed) virtual host best
2567 matching the current IP address and port combination.</p>
2572 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2573 <div class="directive-section"><h2><a name="LimitXMLRequestBody" id="LimitXMLRequestBody">LimitXMLRequestBody</a> <a name="limitxmlrequestbody" id="limitxmlrequestbody">Directive</a></h2>
2574 <table class="directive">
2575 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of an XML-based request body</td></tr>
2576 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitXMLRequestBody <var>bytes</var></code></td></tr>
2577 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitXMLRequestBody 1000000</code></td></tr>
2578 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2579 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2580 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2581 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2583 <p>Limit (in bytes) on maximum size of an XML-based request
2584 body. A value of <code>0</code> will disable any checking.</p>
2588 <pre class="prettyprint lang-config">LimitXMLRequestBody 0</pre>
2593 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2594 <div class="directive-section"><h2><a name="Location" id="Location"><Location></a> <a name="location" id="location">Directive</a></h2>
2595 <table class="directive">
2596 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to matching
2598 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Location
2599 <var>URL-path</var>|<var>URL</var>> ... </Location></code></td></tr>
2600 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2601 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2602 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2604 <p>The <code class="directive"><Location></code> directive
2605 limits the scope of the enclosed directives by URL. It is similar to the
2606 <code class="directive"><a href="#directory"><Directory></a></code>
2607 directive, and starts a subsection which is terminated with a
2608 <code></Location></code> directive. <code class="directive"><Location></code> sections are processed in the
2609 order they appear in the configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
2610 <code>.htaccess</code> files are read, and after the <code class="directive"><a href="#files"><Files></a></code> sections.</p>
2612 <p><code class="directive"><Location></code> sections operate
2613 completely outside the filesystem. This has several consequences.
2614 Most importantly, <code class="directive"><Location></code>
2615 directives should not be used to control access to filesystem
2616 locations. Since several different URLs may map to the same
2617 filesystem location, such access controls may by circumvented.</p>
2619 <p>The enclosed directives will be applied to the request if the path component
2620 of the URL meets <em>any</em> of the following criteria:
2623 <li>The specified location matches exactly the path component of the URL.
2625 <li>The specified location, which ends in a forward slash, is a prefix
2626 of the path component of the URL (treated as a context root).
2628 <li>The specified location, with the addition of a trailing slash, is a
2629 prefix of the path component of the URL (also treated as a context root).
2633 In the example below, where no trailing slash is used, requests to
2634 /private1, /private1/ and /private1/file.txt will have the enclosed
2635 directives applied, but /private1other would not.
2637 <pre class="prettyprint lang-config"><Location /private1>
2639 </Location></pre>
2642 In the example below, where a trailing slash is used, requests to
2643 /private2/ and /private2/file.txt will have the enclosed
2644 directives applied, but /private2 and /private2other would not.
2646 <pre class="prettyprint lang-config"><Location /private2<em>/</em>>
2648 </Location></pre>
2651 <div class="note"><h3>When to use <code class="directive"><Location></code></h3>
2653 <p>Use <code class="directive"><Location></code> to apply
2654 directives to content that lives outside the filesystem. For
2655 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
2656 <code><Location /></code>, which is an easy way to
2657 apply a configuration to the entire server.</p>
2660 <p>For all origin (non-proxy) requests, the URL to be matched is a
2661 URL-path of the form <code>/path/</code>. <em>No scheme, hostname,
2662 port, or query string may be included.</em> For proxy requests, the
2663 URL to be matched is of the form
2664 <code>scheme://servername/path</code>, and you must include the
2667 <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
2668 any single character, and <code>*</code> matches any sequences of
2669 characters. Neither wildcard character matches a / in the URL-path.</p>
2671 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
2672 can also be used, with the addition of the <code>~</code>
2673 character. For example:</p>
2675 <pre class="prettyprint lang-config"><Location ~ "/(extra|special)/data">
2677 </Location></pre>
2680 <p>would match URLs that contained the substring <code>/extra/data</code>
2681 or <code>/special/data</code>. The directive <code class="directive"><a href="#locationmatch"><LocationMatch></a></code> behaves
2682 identical to the regex version of <code class="directive"><Location></code>, and is preferred, for the
2683 simple reason that <code>~</code> is hard to distinguish from
2684 <code>-</code> in many fonts.</p>
2686 <p>The <code class="directive"><Location></code>
2687 functionality is especially useful when combined with the
2688 <code class="directive"><a href="#sethandler">SetHandler</a></code>
2689 directive. For example, to enable status requests, but allow them
2690 only from browsers at <code>example.com</code>, you might use:</p>
2692 <pre class="prettyprint lang-config"><Location /status>
2693 SetHandler server-status
2694 Require host example.com
2695 </Location></pre>
2698 <div class="note"><h3>Note about / (slash)</h3>
2699 <p>The slash character has special meaning depending on where in a
2700 URL it appears. People may be used to its behavior in the filesystem
2701 where multiple adjacent slashes are frequently collapsed to a single
2702 slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
2703 <code>/home/foo</code>). In URL-space this is not necessarily true.
2704 The <code class="directive"><a href="#locationmatch"><LocationMatch></a></code>
2705 directive and the regex version of <code class="directive"><Location></code> require you to explicitly specify multiple
2706 slashes if that is your intention.</p>
2708 <p>For example, <code><LocationMatch ^/abc></code> would match
2709 the request URL <code>/abc</code> but not the request URL <code>
2710 //abc</code>. The (non-regex) <code class="directive"><Location></code> directive behaves similarly when used for
2711 proxy requests. But when (non-regex) <code class="directive"><Location></code> is used for non-proxy requests it will
2712 implicitly match multiple slashes with a single slash. For example,
2713 if you specify <code><Location /abc/def></code> and the
2714 request is to <code>/abc//def</code> then it will match.</p>
2719 <li><a href="../sections.html">How <Directory>, <Location>
2720 and <Files> sections work</a> for an explanation of how these
2721 different sections are combined when a request is received.</li>
2722 <li><code class="directive"><a href="#locationmatch">LocationMatch</a></code></li>
2725 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2726 <div class="directive-section"><h2><a name="LocationMatch" id="LocationMatch"><LocationMatch></a> <a name="locationmatch" id="locationmatch">Directive</a></h2>
2727 <table class="directive">
2728 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to regular-expression
2729 matching URLs</td></tr>
2730 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LocationMatch
2731 <var>regex</var>> ... </LocationMatch></code></td></tr>
2732 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2733 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2734 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2736 <p>The <code class="directive"><LocationMatch></code> directive
2737 limits the scope of the enclosed directives by URL, in an identical manner
2738 to <code class="directive"><a href="#location"><Location></a></code>. However,
2739 it takes a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
2740 as an argument instead of a simple string. For example:</p>
2742 <pre class="prettyprint lang-config"><LocationMatch "/(extra|special)/data">
2744 </LocationMatch></pre>
2747 <p>would match URLs that contained the substring <code>/extra/data</code>
2748 or <code>/special/data</code>.</p>
2750 <p>From 2.4.8 onwards, named groups and backreferences are captured and
2751 written to the environment with the corresponding name prefixed with
2752 "MATCH_" and in upper case. This allows elements of URLs to be referenced
2753 from within <a href="../expr.html">expressions</a> and modules like
2754 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
2755 (unnamed) backreferences are ignored. Use named groups instead.</p>
2757 <pre class="prettyprint lang-config"><LocationMatch ^/combined/(?<sitename>[^/]+)>
2758 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
2759 </LocationMatch></pre>
2764 <li><a href="../sections.html">How <Directory>, <Location>
2765 and <Files> sections work</a> for an explanation of how these
2766 different sections are combined when a request is received</li>
2769 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2770 <div class="directive-section"><h2><a name="LogLevel" id="LogLevel">LogLevel</a> <a name="loglevel" id="loglevel">Directive</a></h2>
2771 <table class="directive">
2772 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Controls the verbosity of the ErrorLog</td></tr>
2773 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel [<var>module</var>:]<var>level</var>
2774 [<var>module</var>:<var>level</var>] ...
2776 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LogLevel warn</code></td></tr>
2777 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2778 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2779 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2780 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Per-module and per-directory configuration is available in
2781 Apache HTTP Server 2.3.6 and later</td></tr>
2783 <p><code class="directive">LogLevel</code> adjusts the verbosity of the
2784 messages recorded in the error logs (see <code class="directive"><a href="#errorlog">ErrorLog</a></code> directive). The following
2785 <var>level</var>s are available, in order of decreasing
2788 <table class="bordered">
2791 <th><strong>Level</strong> </th>
2793 <th><strong>Description</strong> </th>
2795 <th><strong>Example</strong> </th>
2799 <td><code>emerg</code> </td>
2801 <td>Emergencies - system is unusable.</td>
2803 <td>"Child cannot open lock file. Exiting"</td>
2807 <td><code>alert</code> </td>
2809 <td>Action must be taken immediately.</td>
2811 <td>"getpwuid: couldn't determine user name from uid"</td>
2815 <td><code>crit</code> </td>
2817 <td>Critical Conditions.</td>
2819 <td>"socket: Failed to get a socket, exiting child"</td>
2823 <td><code>error</code> </td>
2825 <td>Error conditions.</td>
2827 <td>"Premature end of script headers"</td>
2831 <td><code>warn</code> </td>
2833 <td>Warning conditions.</td>
2835 <td>"child process 1234 did not exit, sending another
2840 <td><code>notice</code> </td>
2842 <td>Normal but significant condition.</td>
2844 <td>"httpd: caught SIGBUS, attempting to dump core in
2849 <td><code>info</code> </td>
2851 <td>Informational.</td>
2853 <td>"Server seems busy, (you may need to increase
2854 StartServers, or Min/MaxSpareServers)..."</td>
2858 <td><code>debug</code> </td>
2860 <td>Debug-level messages</td>
2862 <td>"Opening config file ..."</td>
2865 <td><code>trace1</code> </td>
2867 <td>Trace messages</td>
2869 <td>"proxy: FTP: control connection complete"</td>
2872 <td><code>trace2</code> </td>
2874 <td>Trace messages</td>
2876 <td>"proxy: CONNECT: sending the CONNECT request to the remote proxy"</td>
2879 <td><code>trace3</code> </td>
2881 <td>Trace messages</td>
2883 <td>"openssl: Handshake: start"</td>
2886 <td><code>trace4</code> </td>
2888 <td>Trace messages</td>
2890 <td>"read from buffered SSL brigade, mode 0, 17 bytes"</td>
2893 <td><code>trace5</code> </td>
2895 <td>Trace messages</td>
2897 <td>"map lookup FAILED: map=rewritemap key=keyname"</td>
2900 <td><code>trace6</code> </td>
2902 <td>Trace messages</td>
2904 <td>"cache lookup FAILED, forcing new map lookup"</td>
2907 <td><code>trace7</code> </td>
2909 <td>Trace messages, dumping large amounts of data</td>
2911 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2914 <td><code>trace8</code> </td>
2916 <td>Trace messages, dumping large amounts of data</td>
2918 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2922 <p>When a particular level is specified, messages from all
2923 other levels of higher significance will be reported as well.
2924 <em>E.g.</em>, when <code>LogLevel info</code> is specified,
2925 then messages with log levels of <code>notice</code> and
2926 <code>warn</code> will also be posted.</p>
2928 <p>Using a level of at least <code>crit</code> is
2933 <pre class="prettyprint lang-config">LogLevel notice</pre>
2936 <div class="note"><h3>Note</h3>
2937 <p>When logging to a regular file messages of the level
2938 <code>notice</code> cannot be suppressed and thus are always
2939 logged. However, this doesn't apply when logging is done
2940 using <code>syslog</code>.</p>
2943 <p>Specifying a level without a module name will reset the level
2944 for all modules to that level. Specifying a level with a module
2945 name will set the level for that module only. It is possible to
2946 use the module source file name, the module identifier, or the
2947 module identifier with the trailing <code>_module</code> omitted
2948 as module specification. This means the following three specifications
2951 <pre class="prettyprint lang-config">LogLevel info ssl:warn
2952 LogLevel info mod_ssl.c:warn
2953 LogLevel info ssl_module:warn</pre>
2956 <p>It is also possible to change the level per directory:</p>
2958 <pre class="prettyprint lang-config">LogLevel info
2959 <Directory "/usr/local/apache/htdocs/app">
2961 </Directory></pre>
2965 Per directory loglevel configuration only affects messages that are
2966 logged after the request has been parsed and that are associated with
2967 the request. Log messages which are associated with the server or
2968 the connection are not affected. The latter can be influenced by the
2969 <code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code> directive,
2975 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
2976 <li><code class="directive"><a href="#errorlogformat">ErrorLogFormat</a></code></li>
2977 <li><code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code></li>
2978 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
2981 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2982 <div class="directive-section"><h2><a name="LogLevelOverride" id="LogLevelOverride">LogLevelOverride</a> <a name="logleveloverride" id="logleveloverride">Directive</a></h2>
2983 <table class="directive">
2984 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Override the verbosity of the ErrorLog for certain clients</td></tr>
2985 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel <var>ipaddress</var>[/<var>prefixlen</var>]
2986 [<var>module</var>:]<var>level</var> [<var>module</var>:<var>level</var>] ...
2988 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>unset</code></td></tr>
2989 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2990 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2991 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2992 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.5.0 and later</td></tr>
2994 <p><code class="directive">LogLevelOverride</code> adjusts the
2995 <code class="directive"><a href="#loglevel">LogLevel</a></code> for requests coming from
2996 certain client IP addresses.
2997 This allows to enable verbose logging only for certain test clients.
2998 The IP address is checked at a very early state in the connection
2999 processing. Therefore, <code class="directive">LogLevelOverride</code> allows to
3000 change the log level for things like the SSL handshake which happen before
3001 a <code class="directive"><a href="#loglevel">LogLevel</a></code> directive in an
3002 <code class="directive"><a href="#if"><If></a></code> container would
3005 <p><code class="directive">LogLevelOverride</code> accepts either a single
3006 IP-address or a CIDR IP-address/len subnet specification.
3007 For the syntax of the loglevel specification, see the
3008 <code class="directive"><a href="#loglevel">LogLevel</a></code> directive.</p>
3010 <p>For requests that match a <code class="directive">LogLevelOverride</code>
3011 directive, per-directory specifications of
3012 <code class="directive"><a href="#loglevel">LogLevel</a></code> are ignored.</p>
3016 <pre class="prettyprint lang-config"> LogLevelOverride 192.0.2.0/24 ssl:trace6
3017 LogLevelOverride 192.0.2.7 ssl:trace8</pre>
3021 <code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code> only affects
3022 log messages that are associated with the request or the connection.
3023 Log messages which are associated with the server not affected.
3029 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
3032 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3033 <div class="directive-section"><h2><a name="MaxKeepAliveRequests" id="MaxKeepAliveRequests">MaxKeepAliveRequests</a> <a name="maxkeepaliverequests" id="maxkeepaliverequests">Directive</a></h2>
3034 <table class="directive">
3035 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of requests allowed on a persistent
3036 connection</td></tr>
3037 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxKeepAliveRequests <var>number</var></code></td></tr>
3038 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxKeepAliveRequests 100</code></td></tr>
3039 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3040 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3041 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3043 <p>The <code class="directive">MaxKeepAliveRequests</code> directive
3044 limits the number of requests allowed per connection when
3045 <code class="directive"><a href="#keepalive">KeepAlive</a></code> is on. If it is
3046 set to <code>0</code>, unlimited requests will be allowed. We
3047 recommend that this setting be kept to a high value for maximum
3048 server performance.</p>
3052 <pre class="prettyprint lang-config">MaxKeepAliveRequests 500</pre>
3056 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3057 <div class="directive-section"><h2><a name="MaxRangeOverlaps" id="MaxRangeOverlaps">MaxRangeOverlaps</a> <a name="maxrangeoverlaps" id="maxrangeoverlaps">Directive</a></h2>
3058 <table class="directive">
3059 <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
3061 <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>
3062 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeOverlaps 20</code></td></tr>
3063 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3064 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3065 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3066 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3068 <p>The <code class="directive">MaxRangeOverlaps</code> directive
3069 limits the number of overlapping HTTP ranges the server is willing to
3070 return to the client. If more overlapping ranges than permitted are requested,
3071 the complete resource is returned instead.</p>
3074 <dt><strong>default</strong></dt>
3075 <dd>Limits the number of overlapping ranges to a compile-time default of 20.</dd>
3077 <dt><strong>none</strong></dt>
3078 <dd>No overlapping Range headers are allowed.</dd>
3080 <dt><strong>unlimited</strong></dt>
3081 <dd>The server does not limit the number of overlapping ranges it is
3082 willing to satisfy.</dd>
3084 <dt><var>number-of-ranges</var></dt>
3085 <dd>A positive number representing the maximum number of overlapping ranges the
3086 server is willing to satisfy.</dd>
3090 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3091 <div class="directive-section"><h2><a name="MaxRangeReversals" id="MaxRangeReversals">MaxRangeReversals</a> <a name="maxrangereversals" id="maxrangereversals">Directive</a></h2>
3092 <table class="directive">
3093 <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
3095 <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>
3096 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeReversals 20</code></td></tr>
3097 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3098 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3099 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3100 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3102 <p>The <code class="directive">MaxRangeReversals</code> directive
3103 limits the number of HTTP Range reversals the server is willing to
3104 return to the client. If more ranges reversals than permitted are requested,
3105 the complete resource is returned instead.</p>
3108 <dt><strong>default</strong></dt>
3109 <dd>Limits the number of range reversals to a compile-time default of 20.</dd>
3111 <dt><strong>none</strong></dt>
3112 <dd>No Range reversals headers are allowed.</dd>
3114 <dt><strong>unlimited</strong></dt>
3115 <dd>The server does not limit the number of range reversals it is
3116 willing to satisfy.</dd>
3118 <dt><var>number-of-ranges</var></dt>
3119 <dd>A positive number representing the maximum number of range reversals the
3120 server is willing to satisfy.</dd>
3124 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3125 <div class="directive-section"><h2><a name="MaxRanges" id="MaxRanges">MaxRanges</a> <a name="maxranges" id="maxranges">Directive</a></h2>
3126 <table class="directive">
3127 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of ranges allowed before returning the complete
3129 <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>
3130 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRanges 200</code></td></tr>
3131 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3132 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3133 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3134 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3136 <p>The <code class="directive">MaxRanges</code> directive
3137 limits the number of HTTP ranges the server is willing to
3138 return to the client. If more ranges than permitted are requested,
3139 the complete resource is returned instead.</p>
3142 <dt><strong>default</strong></dt>
3143 <dd>Limits the number of ranges to a compile-time default of 200.</dd>
3145 <dt><strong>none</strong></dt>
3146 <dd>Range headers are ignored.</dd>
3148 <dt><strong>unlimited</strong></dt>
3149 <dd>The server does not limit the number of ranges it is
3150 willing to satisfy.</dd>
3152 <dt><var>number-of-ranges</var></dt>
3153 <dd>A positive number representing the maximum number of ranges the
3154 server is willing to satisfy.</dd>
3158 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3159 <div class="directive-section"><h2><a name="MergeTrailers" id="MergeTrailers">MergeTrailers</a> <a name="mergetrailers" id="mergetrailers">Directive</a></h2>
3160 <table class="directive">
3161 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determins whether trailers are merged into headers</td></tr>
3162 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MergeTrailers [on|off]</code></td></tr>
3163 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MergeTrailers off</code></td></tr>
3164 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3165 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3166 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3167 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.4.10 and later</td></tr>
3169 <p>This directive controls whether HTTP trailers are copied into the
3170 internal representation of HTTP headers. This mergeing occurs when the
3171 request body has been completely consumed, long after most header
3172 processing would have a chance to examine or modify request headers.</p>
3173 <p>This option is provided for compatibility with releases prior to 2.4.10,
3174 where trailers were always merged.</p>
3177 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3178 <div class="directive-section"><h2><a name="Mutex" id="Mutex">Mutex</a> <a name="mutex" id="mutex">Directive</a></h2>
3179 <table class="directive">
3180 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures mutex mechanism and lock file directory for all
3181 or specified mutexes</td></tr>
3182 <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>
3183 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Mutex default</code></td></tr>
3184 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3185 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3186 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3187 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.4 and later</td></tr>
3189 <p>The <code class="directive">Mutex</code> directive sets the mechanism,
3190 and optionally the lock file location, that httpd and modules use
3191 to serialize access to resources. Specify <code>default</code> as
3192 the first argument to change the settings for all mutexes; specify
3193 a mutex name (see table below) as the first argument to override
3194 defaults only for that mutex.</p>
3196 <p>The <code class="directive">Mutex</code> directive is typically used in
3197 the following exceptional situations:</p>
3200 <li>change the mutex mechanism when the default mechanism selected
3201 by <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> has a functional or performance
3204 <li>change the directory used by file-based mutexes when the
3205 default directory does not support locking</li>
3208 <div class="note"><h3>Supported modules</h3>
3209 <p>This directive only configures mutexes which have been registered
3210 with the core server using the <code>ap_mutex_register()</code> API.
3211 All modules bundled with httpd support the <code class="directive">Mutex</code>
3212 directive, but third-party modules may not. Consult the documentation
3213 of the third-party module, which must indicate the mutex name(s) which
3214 can be configured if this directive is supported.</p>
3217 <p>The following mutex <em>mechanisms</em> are available:</p>
3219 <li><code>default | yes</code>
3220 <p>This selects the default locking implementation, as determined by
3221 <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a>. The default locking implementation can
3222 be displayed by running <code class="program"><a href="../programs/httpd.html">httpd</a></code> with the
3223 <code>-V</code> option.</p></li>
3225 <li><code>none | no</code>
3226 <p>This effectively disables the mutex, and is only allowed for a
3227 mutex if the module indicates that it is a valid choice. Consult the
3228 module documentation for more information.</p></li>
3230 <li><code>posixsem</code>
3231 <p>This is a mutex variant based on a Posix semaphore.</p>
3233 <div class="warning"><h3>Warning</h3>
3234 <p>The semaphore ownership is not recovered if a thread in the process
3235 holding the mutex segfaults, resulting in a hang of the web server.</p>
3239 <li><code>sysvsem</code>
3240 <p>This is a mutex variant based on a SystemV IPC semaphore.</p>
3242 <div class="warning"><h3>Warning</h3>
3243 <p>It is possible to "leak" SysV semaphores if processes crash
3244 before the semaphore is removed.</p>
3247 <div class="warning"><h3>Security</h3>
3248 <p>The semaphore API allows for a denial of service attack by any
3249 CGIs running under the same uid as the webserver (<em>i.e.</em>,
3250 all CGIs, unless you use something like <code class="program"><a href="../programs/suexec.html">suexec</a></code>
3251 or <code>cgiwrapper</code>).</p>
3255 <li><code>sem</code>
3256 <p>This selects the "best" available semaphore implementation, choosing
3257 between Posix and SystemV IPC semaphores, in that order.</p></li>
3259 <li><code>pthread</code>
3260 <p>This is a mutex variant based on cross-process Posix thread
3263 <div class="warning"><h3>Warning</h3>
3264 <p>On most systems, if a child process terminates abnormally while
3265 holding a mutex that uses this implementation, the server will deadlock
3266 and stop responding to requests. When this occurs, the server will
3267 require a manual restart to recover.</p>
3268 <p>Solaris is a notable exception as it provides a mechanism which
3269 usually allows the mutex to be recovered after a child process
3270 terminates abnormally while holding a mutex.</p>
3271 <p>If your system implements the
3272 <code>pthread_mutexattr_setrobust_np()</code> function, you may be able
3273 to use the <code>pthread</code> option safely.</p>
3277 <li><code>fcntl:/path/to/mutex</code>
3278 <p>This is a mutex variant where a physical (lock-)file and the
3279 <code>fcntl()</code> function are used as the mutex.</p>
3281 <div class="warning"><h3>Warning</h3>
3282 <p>When multiple mutexes based on this mechanism are used within
3283 multi-threaded, multi-process environments, deadlock errors (EDEADLK)
3284 can be reported for valid mutex operations if <code>fcntl()</code>
3285 is not thread-aware, such as on Solaris.</p>
3289 <li><code>flock:/path/to/mutex</code>
3290 <p>This is similar to the <code>fcntl:/path/to/mutex</code> method
3291 with the exception that the <code>flock()</code> function is used to
3292 provide file locking.</p></li>
3294 <li><code>file:/path/to/mutex</code>
3295 <p>This selects the "best" available file locking implementation,
3296 choosing between <code>fcntl</code> and <code>flock</code>, in that
3300 <p>Most mechanisms are only available on selected platforms, where the
3301 underlying platform and <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> support it. Mechanisms
3302 which aren't available on all platforms are <em>posixsem</em>,
3303 <em>sysvsem</em>, <em>sem</em>, <em>pthread</em>, <em>fcntl</em>,
3304 <em>flock</em>, and <em>file</em>.</p>
3306 <p>With the file-based mechanisms <em>fcntl</em> and <em>flock</em>,
3307 the path, if provided, is a directory where the lock file will be created.
3308 The default directory is httpd's run-time file directory,
3309 <code class="directive"><a href="#defaultruntimedir">DefaultRuntimeDir</a></code>. If a relative
3310 path is provided, it is relative to
3311 <code class="directive"><a href="#defaultruntimedir">DefaultRuntimeDir</a></code>. Always use a local
3312 disk filesystem for <code>/path/to/mutex</code> and never a directory residing
3313 on a NFS- or AFS-filesystem. The basename of the file will be the mutex
3314 type, an optional instance string provided by the module, and unless the
3315 <code>OmitPID</code> keyword is specified, the process id of the httpd
3316 parent process will be appended to to make the file name unique, avoiding
3317 conflicts when multiple httpd instances share a lock file directory. For
3318 example, if the mutex name is <code>mpm-accept</code> and the lock file
3319 directory is <code>/var/httpd/locks</code>, the lock file name for the
3320 httpd instance with parent process id 12345 would be
3321 <code>/var/httpd/locks/mpm-accept.12345</code>.</p>
3323 <div class="warning"><h3>Security</h3>
3324 <p>It is best to <em>avoid</em> putting mutex files in a world-writable
3325 directory such as <code>/var/tmp</code> because someone could create
3326 a denial of service attack and prevent the server from starting by
3327 creating a lockfile with the same name as the one the server will try
3331 <p>The following table documents the names of mutexes used by httpd
3332 and bundled modules.</p>
3334 <table class="bordered"><tr class="header">
3337 <th>Protected resource</th>
3340 <td><code>mpm-accept</code></td>
3341 <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>
3342 <td>incoming connections, to avoid the thundering herd problem;
3343 for more information, refer to the
3344 <a href="../misc/perf-tuning.html">performance tuning</a>
3348 <td><code>authdigest-client</code></td>
3349 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3350 <td>client list in shared memory</td>
3353 <td><code>authdigest-opaque</code></td>
3354 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3355 <td>counter in shared memory</td>
3358 <td><code>ldap-cache</code></td>
3359 <td><code class="module"><a href="../mod/mod_ldap.html">mod_ldap</a></code></td>
3360 <td>LDAP result cache</td>
3363 <td><code>rewrite-map</code></td>
3364 <td><code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code></td>
3365 <td>communication with external mapping programs, to avoid
3366 intermixed I/O from multiple requests</td>
3369 <td><code>ssl-cache</code></td>
3370 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3371 <td>SSL session cache</td>
3374 <td><code>ssl-stapling</code></td>
3375 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3376 <td>OCSP stapling response cache</td>
3379 <td><code>watchdog-callback</code></td>
3380 <td><code class="module"><a href="../mod/mod_watchdog.html">mod_watchdog</a></code></td>
3381 <td>callback function of a particular client module</td>
3385 <p>The <code>OmitPID</code> keyword suppresses the addition of the httpd
3386 parent process id from the lock file name.</p>
3388 <p>In the following example, the mutex mechanism for the MPM accept
3389 mutex will be changed from the compiled-in default to <code>fcntl</code>,
3390 with the associated lock file created in directory
3391 <code>/var/httpd/locks</code>. The mutex mechanism for all other mutexes
3392 will be changed from the compiled-in default to <code>sysvsem</code>.</p>
3394 <pre class="prettyprint lang-config">Mutex sysvsem default
3395 Mutex fcntl:/var/httpd/locks mpm-accept</pre>
3399 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3400 <div class="directive-section"><h2><a name="NameVirtualHost" id="NameVirtualHost">NameVirtualHost</a> <a name="namevirtualhost" id="namevirtualhost">Directive</a></h2>
3401 <table class="directive">
3402 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>DEPRECATED: Designates an IP address for name-virtual
3404 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NameVirtualHost <var>addr</var>[:<var>port</var>]</code></td></tr>
3405 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3406 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3407 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3410 <p>Prior to 2.3.11, <code class="directive">NameVirtualHost</code> was required
3411 to instruct the server that a particular IP address and port combination
3412 was usable as a name-based virtual host. In 2.3.11 and later,
3413 any time an IP address and port combination is used in multiple virtual
3414 hosts, name-based virtual hosting is automatically enabled for that address.</p>
3416 <p>This directive currently has no effect.</p>
3420 <li><a href="../vhosts/">Virtual Hosts
3421 documentation</a></li>
3424 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3425 <div class="directive-section"><h2><a name="Options" id="Options">Options</a> <a name="options" id="options">Directive</a></h2>
3426 <table class="directive">
3427 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures what features are available in a particular
3429 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Options
3430 [+|-]<var>option</var> [[+|-]<var>option</var>] ...</code></td></tr>
3431 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Options FollowSymlinks</code></td></tr>
3432 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3433 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
3434 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3435 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3436 <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>
3438 <p>The <code class="directive">Options</code> directive controls which
3439 server features are available in a particular directory.</p>
3441 <p><var>option</var> can be set to <code>None</code>, in which
3442 case none of the extra features are enabled, or one or more of
3446 <dt><code>All</code></dt>
3448 <dd>All options except for <code>MultiViews</code>.</dd>
3450 <dt><code>ExecCGI</code></dt>
3453 Execution of CGI scripts using <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>
3456 <dt><code>FollowSymLinks</code></dt>
3459 The server will follow symbolic links in this directory. This is
3460 the default setting.
3462 <p>Even though the server follows the symlink it does <em>not</em>
3463 change the pathname used to match against <code class="directive"><a href="#directory"><Directory></a></code> sections.</p>
3465 <p>The <code>FollowSymLinks</code> and
3466 <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
3467 <code>.htaccess</code> files.</p>
3469 <p>Omitting this option should not be considered a security restriction,
3470 since symlink testing is subject to race conditions that make it
3474 <dt><code>Includes</code></dt>
3477 Server-side includes provided by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
3480 <dt><code>IncludesNOEXEC</code></dt>
3484 Server-side includes are permitted, but the <code>#exec
3485 cmd</code> and <code>#exec cgi</code> are disabled. It is still
3486 possible to <code>#include virtual</code> CGI scripts from
3487 <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>ed
3490 <dt><code>Indexes</code></dt>
3493 If a URL which maps to a directory is requested, and there
3494 is no <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
3495 (<em>e.g.</em>, <code>index.html</code>) in that directory, then
3496 <code class="module"><a href="../mod/mod_autoindex.html">mod_autoindex</a></code> will return a formatted listing
3497 of the directory.</dd>
3499 <dt><code>MultiViews</code></dt>
3502 <a href="../content-negotiation.html">Content negotiated</a>
3503 "MultiViews" are allowed using
3504 <code class="module"><a href="../mod/mod_negotiation.html">mod_negotiation</a></code>.
3505 <div class="note"><h3>Note</h3> <p>This option gets ignored if set
3506 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>
3507 needs real resources to compare against and evaluate from.</p></div>
3510 <dt><code>SymLinksIfOwnerMatch</code></dt>
3512 <dd>The server will only follow symbolic links for which the
3513 target file or directory is owned by the same user id as the
3516 <div class="note"><h3>Note</h3>
3517 <p>The <code>FollowSymLinks</code> and
3518 <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
3519 <code>.htaccess</code> files.</p>
3521 <p>This option should not be considered a security restriction,
3522 since symlink testing is subject to race conditions that make it
3527 <p>Normally, if multiple <code class="directive">Options</code> could
3528 apply to a directory, then the most specific one is used and
3529 others are ignored; the options are not merged. (See <a href="../sections.html#mergin">how sections are merged</a>.)
3530 However if <em>all</em> the options on the
3531 <code class="directive">Options</code> directive are preceded by a
3532 <code>+</code> or <code>-</code> symbol, the options are
3533 merged. Any options preceded by a <code>+</code> are added to the
3534 options currently in force, and any options preceded by a
3535 <code>-</code> are removed from the options currently in
3538 <div class="note"><h3>Note</h3>
3539 <p>Mixing <code class="directive">Options</code> with a <code>+</code> or
3540 <code>-</code> with those without is not valid syntax, and will be
3541 rejected during server startup by the syntax check with an abort.</p>
3544 <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>
3546 <pre class="prettyprint lang-config"><Directory "/web/docs">
3547 Options Indexes FollowSymLinks
3550 <Directory "/web/docs/spec">
3552 </Directory></pre>
3555 <p>then only <code>Includes</code> will be set for the
3556 <code>/web/docs/spec</code> directory. However if the second
3557 <code class="directive">Options</code> directive uses the <code>+</code> and
3558 <code>-</code> symbols:</p>
3560 <pre class="prettyprint lang-config"><Directory "/web/docs">
3561 Options Indexes FollowSymLinks
3564 <Directory "/web/docs/spec">
3565 Options +Includes -Indexes
3566 </Directory></pre>
3569 <p>then the options <code>FollowSymLinks</code> and
3570 <code>Includes</code> are set for the <code>/web/docs/spec</code>
3573 <div class="note"><h3>Note</h3>
3574 <p>Using <code>-IncludesNOEXEC</code> or
3575 <code>-Includes</code> disables server-side includes completely
3576 regardless of the previous setting.</p>
3579 <p>The default in the absence of any other settings is
3580 <code>FollowSymlinks</code>.</p>
3583 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3584 <div class="directive-section"><h2><a name="Protocol" id="Protocol">Protocol</a> <a name="protocol" id="protocol">Directive</a></h2>
3585 <table class="directive">
3586 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Protocol for a listening socket</td></tr>
3587 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Protocol <var>protocol</var></code></td></tr>
3588 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3589 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3590 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3591 <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>
3593 <p>This directive specifies the protocol used for a specific listening socket.
3594 The protocol is used to determine which module should handle a request, and
3595 to apply protocol specific optimizations with the <code class="directive">AcceptFilter</code>
3598 <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>
3600 <p>For example, if you are running <code>https</code> on a non-standard port, specify the protocol explicitly:</p>
3602 <pre class="prettyprint lang-config">Protocol https</pre>
3605 <p>You can also specify the protocol using the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code> directive.</p>
3609 <li><code class="directive"><a href="#acceptfilter">AcceptFilter</a></code></li>
3610 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
3613 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3614 <div class="directive-section"><h2><a name="RegisterHttpMethod" id="RegisterHttpMethod">RegisterHttpMethod</a> <a name="registerhttpmethod" id="registerhttpmethod">Directive</a></h2>
3615 <table class="directive">
3616 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Register non-standard HTTP methods</td></tr>
3617 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>RegisterHttpMethod <var>method</var> [<var>method</var> [...]]</code></td></tr>
3618 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3619 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3620 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3622 <p>HTTP Methods that are not conforming to the relvant RFCs are normally
3623 rejected by request processing in Apache HTTPD. To avoid this, modules
3624 can register non-standard HTTP methods they support.
3625 The <code class="directive">RegisterHttpMethod</code> allows to register such
3626 methods manually. This can be useful for if such methods are forwared
3627 for external processing, e.g. to a CGI script.</p>
3630 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3631 <div class="directive-section"><h2><a name="RLimitCPU" id="RLimitCPU">RLimitCPU</a> <a name="rlimitcpu" id="rlimitcpu">Directive</a></h2>
3632 <table class="directive">
3633 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the CPU consumption of processes launched
3634 by Apache httpd children</td></tr>
3635 <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>
3636 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3637 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3638 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3639 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3640 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3642 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3643 resource limit for all processes and the second parameter sets
3644 the maximum resource limit. Either parameter can be a number,
3645 or <code>max</code> to indicate to the server that the limit should
3646 be set to the maximum allowed by the operating system
3647 configuration. Raising the maximum resource limit requires that
3648 the server is running as <code>root</code>, or in the initial startup
3651 <p>This applies to processes forked off from Apache httpd children
3652 servicing requests, not the Apache httpd children themselves. This
3653 includes CGI scripts and SSI exec commands, but not any
3654 processes forked off from the Apache httpd parent such as piped
3657 <p>CPU resource limits are expressed in seconds per
3662 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3663 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3666 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3667 <div class="directive-section"><h2><a name="RLimitMEM" id="RLimitMEM">RLimitMEM</a> <a name="rlimitmem" id="rlimitmem">Directive</a></h2>
3668 <table class="directive">
3669 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the memory consumption of processes launched
3670 by Apache httpd children</td></tr>
3671 <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>
3672 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3673 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3674 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3675 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3676 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3678 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3679 resource limit for all processes and the second parameter sets
3680 the maximum resource limit. Either parameter can be a number,
3681 or <code>max</code> to indicate to the server that the limit should
3682 be set to the maximum allowed by the operating system
3683 configuration. Raising the maximum resource limit requires that
3684 the server is running as <code>root</code>, or in the initial startup
3687 <p>This applies to processes forked off from Apache httpd children
3688 servicing requests, not the Apache httpd children themselves. This
3689 includes CGI scripts and SSI exec commands, but not any
3690 processes forked off from the Apache httpd parent such as piped
3693 <p>Memory resource limits are expressed in bytes per
3698 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3699 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3702 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3703 <div class="directive-section"><h2><a name="RLimitNPROC" id="RLimitNPROC">RLimitNPROC</a> <a name="rlimitnproc" id="rlimitnproc">Directive</a></h2>
3704 <table class="directive">
3705 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of processes that can be launched by
3706 processes launched by Apache httpd children</td></tr>
3707 <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>
3708 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3709 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3710 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3711 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3712 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3714 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3715 resource limit for all processes and the second parameter sets
3716 the maximum resource limit. Either parameter can be a number,
3717 or <code>max</code> to indicate to the server that the limit
3718 should be set to the maximum allowed by the operating system
3719 configuration. Raising the maximum resource limit requires that
3720 the server is running as <code>root</code>, or in the initial startup
3723 <p>This applies to processes forked off from Apache httpd children
3724 servicing requests, not the Apache httpd children themselves. This
3725 includes CGI scripts and SSI exec commands, but not any
3726 processes forked off from the Apache httpd parent such as piped
3729 <p>Process limits control the number of processes per user.</p>
3731 <div class="note"><h3>Note</h3>
3732 <p>If CGI processes are <strong>not</strong> running
3733 under user ids other than the web server user id, this directive
3734 will limit the number of processes that the server itself can
3735 create. Evidence of this situation will be indicated by
3736 <strong><code>cannot fork</code></strong> messages in the
3737 <code>error_log</code>.</p>
3742 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3743 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3746 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3747 <div class="directive-section"><h2><a name="ScriptInterpreterSource" id="ScriptInterpreterSource">ScriptInterpreterSource</a> <a name="scriptinterpretersource" id="scriptinterpretersource">Directive</a></h2>
3748 <table class="directive">
3749 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
3751 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ScriptInterpreterSource Registry|Registry-Strict|Script</code></td></tr>
3752 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ScriptInterpreterSource Script</code></td></tr>
3753 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3754 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3755 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3756 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3757 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Win32 only.</td></tr>
3759 <p>This directive is used to control how Apache httpd finds the
3760 interpreter used to run CGI scripts. The default setting is
3761 <code>Script</code>. This causes Apache httpd to use the interpreter pointed to
3762 by the shebang line (first line, starting with <code>#!</code>) in the
3763 script. On Win32 systems this line usually looks like:</p>
3765 <pre class="prettyprint lang-perl">#!C:/Perl/bin/perl.exe</pre>
3768 <p>or, if <code>perl</code> is in the <code>PATH</code>, simply:</p>
3770 <pre class="prettyprint lang-perl">#!perl</pre>
3773 <p>Setting <code>ScriptInterpreterSource Registry</code> will
3774 cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
3775 searched using the script file extension (e.g., <code>.pl</code>) as a
3776 search key. The command defined by the registry subkey
3777 <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
3778 <code>Shell\Open\Command</code> is used to open the script file. If the
3779 registry keys cannot be found, Apache httpd falls back to the behavior of the
3780 <code>Script</code> option.</p>
3782 <div class="warning"><h3>Security</h3>
3783 <p>Be careful when using <code>ScriptInterpreterSource
3784 Registry</code> with <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>'ed directories, because
3785 Apache httpd will try to execute <strong>every</strong> file within this
3786 directory. The <code>Registry</code> setting may cause undesired
3787 program calls on files which are typically not executed. For
3788 example, the default open command on <code>.htm</code> files on
3789 most Windows systems will execute Microsoft Internet Explorer, so
3790 any HTTP request for an <code>.htm</code> file existing within the
3791 script directory would start the browser in the background on the
3792 server. This is a good way to crash your system within a minute or
3796 <p>The option <code>Registry-Strict</code> which is new in Apache HTTP Server
3797 2.0 does the same thing as <code>Registry</code> but uses only the
3798 subkey <code>Shell\ExecCGI\Command</code>. The
3799 <code>ExecCGI</code> key is not a common one. It must be
3800 configured manually in the windows registry and hence prevents
3801 accidental program calls on your system.</p>
3804 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3805 <div class="directive-section"><h2><a name="SeeRequestTail" id="SeeRequestTail">SeeRequestTail</a> <a name="seerequesttail" id="seerequesttail">Directive</a></h2>
3806 <table class="directive">
3807 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine if mod_status displays the first 63 characters
3808 of a request or the last 63, assuming the request itself is greater than
3810 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SeeRequestTail On|Off</code></td></tr>
3811 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SeeRequestTail Off</code></td></tr>
3812 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3813 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3814 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3816 <p>mod_status with <code>ExtendedStatus On</code>
3817 displays the actual request being handled.
3818 For historical purposes, only 63 characters of the request
3819 are actually stored for display purposes. This directive
3820 controls whether the 1st 63 characters are stored (the previous
3821 behavior and the default) or if the last 63 characters are. This
3822 is only applicable, of course, if the length of the request is
3823 64 characters or greater.</p>
3825 <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:
3828 <table class="bordered">
3830 <th>Off (default)</th>
3831 <td>GET /disk1/storage/apache/htdocs/images/imagestore1/food/apples</td>
3835 <td>orage/apache/htdocs/images/imagestore1/food/apples.jpg HTTP/1.1</td>
3841 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3842 <div class="directive-section"><h2><a name="ServerAdmin" id="ServerAdmin">ServerAdmin</a> <a name="serveradmin" id="serveradmin">Directive</a></h2>
3843 <table class="directive">
3844 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Email address that the server includes in error
3845 messages sent to the client</td></tr>
3846 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAdmin <var>email-address</var>|<var>URL</var></code></td></tr>
3847 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3848 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3849 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3851 <p>The <code class="directive">ServerAdmin</code> sets the contact address
3852 that the server includes in any error messages it returns to the
3853 client. If the <code>httpd</code> doesn't recognize the supplied argument
3855 assumes, that it's an <var>email-address</var> and prepends it with
3856 <code>mailto:</code> in hyperlink targets. However, it's recommended to
3857 actually use an email address, since there are a lot of CGI scripts that
3858 make that assumption. If you want to use an URL, it should point to another
3859 server under your control. Otherwise users may not be able to contact you in
3862 <p>It may be worth setting up a dedicated address for this, e.g.</p>
3864 <pre class="prettyprint lang-config">ServerAdmin www-admin@foo.example.com</pre>
3866 <p>as users do not always mention that they are talking about the
3870 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3871 <div class="directive-section"><h2><a name="ServerAlias" id="ServerAlias">ServerAlias</a> <a name="serveralias" id="serveralias">Directive</a></h2>
3872 <table class="directive">
3873 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Alternate names for a host used when matching requests
3874 to name-virtual hosts</td></tr>
3875 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</code></td></tr>
3876 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
3877 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3878 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3880 <p>The <code class="directive">ServerAlias</code> directive sets the
3881 alternate names for a host, for use with <a href="../vhosts/name-based.html">name-based virtual hosts</a>. The
3882 <code class="directive">ServerAlias</code> may include wildcards, if appropriate.</p>
3884 <pre class="prettyprint lang-config"><VirtualHost *:80>
3885 ServerName server.example.com
3886 ServerAlias server server2.example.com server2
3887 ServerAlias *.example.com
3888 UseCanonicalName Off
3890 </VirtualHost></pre>
3893 <p>Name-based virtual hosts for the best-matching set of <code class="directive"><a href="#virtualhost"><virtualhost></a></code>s are processed
3894 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
3895 (nor for ServerName vs. ServerAlias). </p>
3897 <p>The complete list of names in the <code class="directive">VirtualHost</code>
3898 directive are treated just like a (non wildcard)
3899 <code class="directive">ServerAlias</code>.</p>
3904 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3905 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
3908 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3909 <div class="directive-section"><h2><a name="ServerName" id="ServerName">ServerName</a> <a name="servername" id="servername">Directive</a></h2>
3910 <table class="directive">
3911 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hostname and port that the server uses to identify
3913 <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>
3914 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3915 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3916 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3918 <p>The <code class="directive">ServerName</code> directive sets the
3919 request scheme, hostname and
3920 port that the server uses to identify itself. This is used when
3921 creating redirection URLs.</p>
3923 <p>Additionally, <code class="directive">ServerName</code> is used (possibly
3924 in conjunction with <code class="directive">ServerAlias</code>) to uniquely
3925 identify a virtual host, when using <a href="../vhosts/name-based.html">name-based virtual hosts</a>.</p>
3927 <p>For example, if the name of the
3928 machine hosting the web server is <code>simple.example.com</code>,
3929 but the machine also has the DNS alias <code>www.example.com</code>
3930 and you wish the web server to be so identified, the following
3931 directive should be used:</p>
3933 <pre class="prettyprint lang-config">ServerName www.example.com</pre>
3936 <p>The <code class="directive">ServerName</code> directive
3937 may appear anywhere within the definition of a server. However,
3938 each appearance overrides the previous appearance (within that
3941 <p>If no <code class="directive">ServerName</code> is specified, then the
3942 server attempts to deduce the client visible hostname by performing a
3943 reverse lookup on an IP address of the systems hostname.</p>
3945 <p>If no port is specified in the
3946 <code class="directive">ServerName</code>, then the server will use the
3947 port from the incoming request. For optimal reliability and
3948 predictability, you should specify an explicit hostname and port
3949 using the <code class="directive">ServerName</code> directive.</p>
3951 <p>If you are using <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
3952 the <code class="directive">ServerName</code> inside a
3953 <code class="directive"><a href="#virtualhost"><VirtualHost></a></code>
3954 section specifies what hostname must appear in the request's
3955 <code>Host:</code> header to match this virtual host.</p>
3957 <p>Sometimes, the server runs behind a device that processes SSL,
3958 such as a reverse proxy, load balancer or SSL offload
3959 appliance. When this is the case, specify the
3960 <code>https://</code> scheme and the port number to which the
3961 clients connect in the <code class="directive">ServerName</code> directive
3962 to make sure that the server generates the correct
3963 self-referential URLs.
3966 <p>See the description of the
3967 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> and
3968 <code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code> directives for
3969 settings which determine whether self-referential URLs (e.g., by the
3970 <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> module) will refer to the
3971 specified port, or to the port number given in the client's request.
3974 <div class="warning">
3975 <p>Failure to set <code class="directive">ServerName</code> to a name that
3976 your server can resolve to an IP address will result in a startup
3977 warning. <code>httpd</code> will then use whatever hostname it can
3978 determine, using the system's <code>hostname</code> command. This
3979 will almost never be the hostname you actually want.</p>
3980 <div class="example"><p><code>
3981 httpd: Could not reliably determine the server's fully qualified domain name, using rocinante.local for ServerName
3988 <li><a href="../dns-caveats.html">Issues Regarding DNS and
3989 Apache HTTP Server</a></li>
3990 <li><a href="../vhosts/">Apache HTTP Server virtual host
3991 documentation</a></li>
3992 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3993 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
3994 <li><code class="directive"><a href="#serveralias">ServerAlias</a></code></li>
3997 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3998 <div class="directive-section"><h2><a name="ServerPath" id="ServerPath">ServerPath</a> <a name="serverpath" id="serverpath">Directive</a></h2>
3999 <table class="directive">
4000 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Legacy URL pathname for a name-based virtual host that
4001 is accessed by an incompatible browser</td></tr>
4002 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerPath <var>URL-path</var></code></td></tr>
4003 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
4004 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4005 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4007 <p>The <code class="directive">ServerPath</code> directive sets the legacy
4008 URL pathname for a host, for use with <a href="../vhosts/">name-based virtual hosts</a>.</p>
4012 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4015 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4016 <div class="directive-section"><h2><a name="ServerRoot" id="ServerRoot">ServerRoot</a> <a name="serverroot" id="serverroot">Directive</a></h2>
4017 <table class="directive">
4018 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server installation</td></tr>
4019 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerRoot <var>directory-path</var></code></td></tr>
4020 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerRoot /usr/local/apache</code></td></tr>
4021 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4022 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4023 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4025 <p>The <code class="directive">ServerRoot</code> directive sets the
4026 directory in which the server lives. Typically it will contain the
4027 subdirectories <code>conf/</code> and <code>logs/</code>. Relative
4028 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
4029 relative to this directory.</p>
4031 <pre class="prettyprint lang-config">ServerRoot "/home/httpd"</pre>
4034 <p>The default location of <code class="directive">ServerRoot</code> may be
4035 modified by using the <code>--prefix</code> argument to
4036 <a href="../programs/configure.html"><code>configure</code></a>, and
4037 most third-party distributions of the server have a different
4038 default location from the one listed above.</p>
4043 <li><a href="../invoking.html">the <code>-d</code>
4044 option to <code>httpd</code></a></li>
4045 <li><a href="../misc/security_tips.html#serverroot">the
4046 security tips</a> for information on how to properly set
4047 permissions on the <code class="directive">ServerRoot</code></li>
4050 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4051 <div class="directive-section"><h2><a name="ServerSignature" id="ServerSignature">ServerSignature</a> <a name="serversignature" id="serversignature">Directive</a></h2>
4052 <table class="directive">
4053 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the footer on server-generated documents</td></tr>
4054 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerSignature On|Off|EMail</code></td></tr>
4055 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerSignature Off</code></td></tr>
4056 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4057 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
4058 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4059 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4061 <p>The <code class="directive">ServerSignature</code> directive allows the
4062 configuration of a trailing footer line under server-generated
4063 documents (error messages, <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> ftp directory
4064 listings, <code class="module"><a href="../mod/mod_info.html">mod_info</a></code> output, ...). The reason why you
4065 would want to enable such a footer line is that in a chain of proxies,
4066 the user often has no possibility to tell which of the chained servers
4067 actually produced a returned error message.</p>
4069 <p>The <code>Off</code>
4070 setting, which is the default, suppresses the footer line (and is
4071 therefore compatible with the behavior of Apache-1.2 and
4072 below). The <code>On</code> setting simply adds a line with the
4073 server version number and <code class="directive"><a href="#servername">ServerName</a></code> of the serving virtual host,
4074 and the <code>EMail</code> setting additionally creates a
4075 "mailto:" reference to the <code class="directive"><a href="#serveradmin">ServerAdmin</a></code> of the referenced
4078 <p>After version 2.0.44, the details of the server version number
4079 presented are controlled by the <code class="directive"><a href="#servertokens">ServerTokens</a></code> directive.</p>
4083 <li><code class="directive"><a href="#servertokens">ServerTokens</a></code></li>
4086 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4087 <div class="directive-section"><h2><a name="ServerTokens" id="ServerTokens">ServerTokens</a> <a name="servertokens" id="servertokens">Directive</a></h2>
4088 <table class="directive">
4089 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the <code>Server</code> HTTP response
4091 <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>
4092 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerTokens Full</code></td></tr>
4093 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4094 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4095 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4097 <p>This directive controls whether <code>Server</code> response
4098 header field which is sent back to clients includes a
4099 description of the generic OS-type of the server as well as
4100 information about compiled-in modules.</p>
4103 <dt><code>ServerTokens Full</code> (or not specified)</dt>
4105 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4106 (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
4108 <dt><code>ServerTokens Prod[uctOnly]</code></dt>
4110 <dd>Server sends (<em>e.g.</em>): <code>Server:
4113 <dt><code>ServerTokens Major</code></dt>
4115 <dd>Server sends (<em>e.g.</em>): <code>Server:
4116 Apache/2</code></dd>
4118 <dt><code>ServerTokens Minor</code></dt>
4120 <dd>Server sends (<em>e.g.</em>): <code>Server:
4121 Apache/2.4</code></dd>
4123 <dt><code>ServerTokens Min[imal]</code></dt>
4125 <dd>Server sends (<em>e.g.</em>): <code>Server:
4126 Apache/2.4.2</code></dd>
4128 <dt><code>ServerTokens OS</code></dt>
4130 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4135 <p>This setting applies to the entire server, and cannot be
4136 enabled or disabled on a virtualhost-by-virtualhost basis.</p>
4138 <p>After version 2.0.44, this directive also controls the
4139 information presented by the <code class="directive"><a href="#serversignature">ServerSignature</a></code> directive.</p>
4141 <div class="note">Setting <code class="directive">ServerTokens</code> to less than
4142 <code>minimal</code> is not recommended because it makes it more
4143 difficult to debug interoperational problems. Also note that
4144 disabling the Server: header does nothing at all to make your
4145 server more secure; the idea of "security through obscurity"
4146 is a myth and leads to a false sense of safety.</div>
4151 <li><code class="directive"><a href="#serversignature">ServerSignature</a></code></li>
4154 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4155 <div class="directive-section"><h2><a name="SetHandler" id="SetHandler">SetHandler</a> <a name="sethandler" id="sethandler">Directive</a></h2>
4156 <table class="directive">
4157 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be processed by a
4159 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetHandler <var>handler-name</var>|None</code></td></tr>
4160 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4161 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4162 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4163 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4165 <p>When placed into an <code>.htaccess</code> file or a
4166 <code class="directive"><a href="#directory"><Directory></a></code> or
4167 <code class="directive"><a href="#location"><Location></a></code>
4168 section, this directive forces all matching files to be parsed
4169 through the <a href="../handler.html">handler</a> given by
4170 <var>handler-name</var>. For example, if you had a directory you
4171 wanted to be parsed entirely as imagemap rule files, regardless
4172 of extension, you might put the following into an
4173 <code>.htaccess</code> file in that directory:</p>
4175 <pre class="prettyprint lang-config">SetHandler imap-file</pre>
4178 <p>Another example: if you wanted to have the server display a
4179 status report whenever a URL of
4180 <code>http://servername/status</code> was called, you might put
4181 the following into <code>httpd.conf</code>:</p>
4183 <pre class="prettyprint lang-config"><Location "/status">
4184 SetHandler server-status
4185 </Location></pre>
4188 <p>You could also use this directive to configure a particular
4189 handler for files with a particular file extension. For example:</p>
4191 <pre class="prettyprint lang-config"><FilesMatch \.php$>
4192 SetHandler application/x-httpd-php
4193 </FilesMatch></pre>
4196 <p>You can override an earlier defined <code class="directive">SetHandler</code>
4197 directive by using the value <code>None</code>.</p>
4199 <div class="note"><h3>Note</h3>
4200 <p>Because <code class="directive">SetHandler</code> overrides default handlers,
4201 normal behavior such as handling of URLs ending in a slash (/) as
4202 directories or index files is suppressed.</p></div>
4206 <li><code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code></li>
4209 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4210 <div class="directive-section"><h2><a name="SetInputFilter" id="SetInputFilter">SetInputFilter</a> <a name="setinputfilter" id="setinputfilter">Directive</a></h2>
4211 <table class="directive">
4212 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process client requests and POST
4214 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetInputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4215 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4216 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4217 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4218 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4220 <p>The <code class="directive">SetInputFilter</code> directive sets the
4221 filter or filters which will process client requests and POST
4222 input when they are received by the server. This is in addition to
4223 any filters defined elsewhere, including the
4224 <code class="directive"><a href="../mod/mod_mime.html#addinputfilter">AddInputFilter</a></code>
4227 <p>If more than one filter is specified, they must be separated
4228 by semicolons in the order in which they should process the
4233 <li><a href="../filter.html">Filters</a> documentation</li>
4236 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4237 <div class="directive-section"><h2><a name="SetOutputFilter" id="SetOutputFilter">SetOutputFilter</a> <a name="setoutputfilter" id="setoutputfilter">Directive</a></h2>
4238 <table class="directive">
4239 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process responses from the
4241 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4242 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4243 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4244 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4245 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4247 <p>The <code class="directive">SetOutputFilter</code> directive sets the filters
4248 which will process responses from the server before they are
4249 sent to the client. This is in addition to any filters defined
4250 elsewhere, including the
4251 <code class="directive"><a href="../mod/mod_mime.html#addoutputfilter">AddOutputFilter</a></code>
4254 <p>For example, the following configuration will process all files
4255 in the <code>/www/data/</code> directory for server-side
4258 <pre class="prettyprint lang-config"><Directory "/www/data/">
4259 SetOutputFilter INCLUDES
4260 </Directory></pre>
4263 <p>If more than one filter is specified, they must be separated
4264 by semicolons in the order in which they should process the
4269 <li><a href="../filter.html">Filters</a> documentation</li>
4272 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4273 <div class="directive-section"><h2><a name="TimeOut" id="TimeOut">TimeOut</a> <a name="timeout" id="timeout">Directive</a></h2>
4274 <table class="directive">
4275 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for
4276 certain events before failing a request</td></tr>
4277 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TimeOut <var>seconds</var></code></td></tr>
4278 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TimeOut 60</code></td></tr>
4279 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4280 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4281 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4283 <p>The <code class="directive">TimeOut</code> directive defines the length
4284 of time Apache httpd will wait for I/O in various circumstances:</p>
4287 <li>When reading data from the client, the length of time to
4288 wait for a TCP packet to arrive if the read buffer is
4291 <li>When writing data to the client, the length of time to wait
4292 for an acknowledgement of a packet if the send buffer is
4295 <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>,
4296 the length of time to wait for output from a CGI script.</li>
4298 <li>In <code class="module"><a href="../mod/mod_ext_filter.html">mod_ext_filter</a></code>, the length of time to
4299 wait for output from a filtering process.</li>
4301 <li>In <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>, the default timeout value if
4302 <code class="directive"><a href="../mod/mod_proxy.html#proxytimeout">ProxyTimeout</a></code> is not
4308 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4309 <div class="directive-section"><h2><a name="TraceEnable" id="TraceEnable">TraceEnable</a> <a name="traceenable" id="traceenable">Directive</a></h2>
4310 <table class="directive">
4311 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines the behavior on <code>TRACE</code> requests</td></tr>
4312 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TraceEnable <var>[on|off|extended]</var></code></td></tr>
4313 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TraceEnable on</code></td></tr>
4314 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4315 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4316 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4318 <p>This directive overrides the behavior of <code>TRACE</code> for both
4319 the core server and <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>. The default
4320 <code>TraceEnable on</code> permits <code>TRACE</code> requests per
4321 RFC 2616, which disallows any request body to accompany the request.
4322 <code>TraceEnable off</code> causes the core server and
4323 <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> to return a <code>405</code> (Method not
4324 allowed) error to the client.</p>
4326 <p>Finally, for testing and diagnostic purposes only, request
4327 bodies may be allowed using the non-compliant <code>TraceEnable
4328 extended</code> directive. The core (as an origin server) will
4329 restrict the request body to 64k (plus 8k for chunk headers if
4330 <code>Transfer-Encoding: chunked</code> is used). The core will
4331 reflect the full headers and all chunk headers with the response
4332 body. As a proxy server, the request body is not restricted to 64k.</p>
4334 <div class="note"><h3>Note</h3>
4335 <p>Despite claims to the contrary, <code>TRACE</code> is not
4336 a security vulnerability and there is no viable reason for
4337 it to be disabled. Doing so necessarily makes your server
4342 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4343 <div class="directive-section"><h2><a name="UnDefine" id="UnDefine">UnDefine</a> <a name="undefine" id="undefine">Directive</a></h2>
4344 <table class="directive">
4345 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Undefine the existence of a variable</td></tr>
4346 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UnDefine <var>parameter-name</var></code></td></tr>
4347 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4348 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4349 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4351 <p>Undoes the effect of a <code class="directive"><a href="#define">Define</a></code> or
4352 of passing a <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</p>
4353 <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
4354 <code>-D</code> arguments in any startup scripts.</p>
4355 <p>While this directive is supported in virtual host context,
4356 the changes it makes are visible to any later configuration
4357 directives, beyond any enclosing virtual host</p>
4360 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4361 <div class="directive-section"><h2><a name="UseCanonicalName" id="UseCanonicalName">UseCanonicalName</a> <a name="usecanonicalname" id="usecanonicalname">Directive</a></h2>
4362 <table class="directive">
4363 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own name and
4365 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalName On|Off|DNS</code></td></tr>
4366 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalName Off</code></td></tr>
4367 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4368 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4369 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4371 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4372 URL -- that is, a URL that refers back to the same server. With
4373 <code>UseCanonicalName On</code> Apache httpd will use the hostname and port
4374 specified in the <code class="directive"><a href="#servername">ServerName</a></code>
4375 directive to construct the canonical name for the server. This name
4376 is used in all self-referential URLs, and for the values of
4377 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>
4379 <p>With <code>UseCanonicalName Off</code> Apache httpd will form
4380 self-referential URLs using the hostname and port supplied by
4381 the client if any are supplied (otherwise it will use the
4382 canonical name, as defined above). These values are the same
4383 that are used to implement <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
4384 and are available with the same clients. The CGI variables
4385 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
4386 constructed from the client supplied values as well.</p>
4388 <p>An example where this may be useful is on an intranet server
4389 where you have users connecting to the machine using short
4390 names such as <code>www</code>. You'll notice that if the users
4391 type a shortname, and a URL which is a directory, such as
4392 <code>http://www/splat</code>, <em>without the trailing
4393 slash</em> then Apache httpd will redirect them to
4394 <code>http://www.example.com/splat/</code>. If you have
4395 authentication enabled, this will cause the user to have to
4396 authenticate twice (once for <code>www</code> and once again
4397 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">
4398 the FAQ on this subject for more information</a>). But if
4399 <code class="directive">UseCanonicalName</code> is set <code>Off</code>, then
4400 Apache httpd will redirect to <code>http://www/splat/</code>.</p>
4402 <p>There is a third option, <code>UseCanonicalName DNS</code>,
4403 which is intended for use with mass IP-based virtual hosting to
4404 support ancient clients that do not provide a
4405 <code>Host:</code> header. With this option Apache httpd does a
4406 reverse DNS lookup on the server IP address that the client
4407 connected to in order to work out self-referential URLs.</p>
4409 <div class="warning"><h3>Warning</h3>
4410 <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>
4411 they may be broken by this option. The client is essentially free
4412 to give whatever value they want as a hostname. But if the CGI is
4413 only using <code>SERVER_NAME</code> to construct self-referential URLs
4414 then it should be just fine.</p>
4419 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
4420 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4421 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4424 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4425 <div class="directive-section"><h2><a name="UseCanonicalPhysicalPort" id="UseCanonicalPhysicalPort">UseCanonicalPhysicalPort</a> <a name="usecanonicalphysicalport" id="usecanonicalphysicalport">Directive</a></h2>
4426 <table class="directive">
4427 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own port</td></tr>
4428 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalPhysicalPort On|Off</code></td></tr>
4429 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalPhysicalPort Off</code></td></tr>
4430 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4431 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4432 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4434 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4435 URL -- that is, a URL that refers back to the same server. With
4436 <code>UseCanonicalPhysicalPort On</code> Apache httpd will, when
4437 constructing the canonical port for the server to honor
4438 the <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> directive,
4439 provide the actual physical port number being used by this request
4440 as a potential port. With <code>UseCanonicalPhysicalPort Off</code>
4441 Apache httpd will not ever use the actual physical port number, instead
4442 relying on all configured information to construct a valid port number.</p>
4444 <div class="note"><h3>Note</h3>
4445 <p>The ordering of the lookup when the physical port is used is as
4448 <dt><code>UseCanonicalName On</code></dt>
4451 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4452 <li>Physical port</li>
4453 <li>Default port</li>
4456 <dt><code>UseCanonicalName Off | DNS</code></dt>
4459 <li>Parsed port from <code>Host:</code> header</li>
4460 <li>Physical port</li>
4461 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4462 <li>Default port</li>
4467 <p>With <code>UseCanonicalPhysicalPort Off</code>, the
4468 physical ports are removed from the ordering.</p>
4474 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
4475 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4476 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4479 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4480 <div class="directive-section"><h2><a name="VirtualHost" id="VirtualHost"><VirtualHost></a> <a name="virtualhost" id="virtualhost">Directive</a></h2>
4481 <table class="directive">
4482 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only to a specific
4483 hostname or IP address</td></tr>
4484 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><VirtualHost
4485 <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
4486 ...> ... </VirtualHost></code></td></tr>
4487 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4488 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4489 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4491 <p><code class="directive"><VirtualHost></code> and
4492 <code></VirtualHost></code> are used to enclose a group of
4493 directives that will apply only to a particular virtual host. Any
4494 directive that is allowed in a virtual host context may be
4495 used. When the server receives a request for a document on a
4496 particular virtual host, it uses the configuration directives
4497 enclosed in the <code class="directive"><VirtualHost></code>
4498 section. <var>Addr</var> can be any of the following, optionally followed by
4499 a colon and a port number (or *):</p>
4502 <li>The IP address of the virtual host;</li>
4504 <li>A fully qualified domain name for the IP address of the
4505 virtual host (not recommended);</li>
4507 <li>The character <code>*</code>, which acts as a wildcard and matches
4508 any IP address.</li>
4510 <li>The string <code>_default_</code>, which is an alias for <code>*</code></li>
4514 <pre class="prettyprint lang-config"><VirtualHost 10.1.2.3:80>
4515 ServerAdmin webmaster@host.example.com
4516 DocumentRoot /www/docs/host.example.com
4517 ServerName host.example.com
4518 ErrorLog logs/host.example.com-error_log
4519 TransferLog logs/host.example.com-access_log
4520 </VirtualHost></pre>
4524 <p>IPv6 addresses must be specified in square brackets because
4525 the optional port number could not be determined otherwise. An
4526 IPv6 example is shown below:</p>
4528 <pre class="prettyprint lang-config"><VirtualHost [2001:db8::a00:20ff:fea7:ccea]:80>
4529 ServerAdmin webmaster@host.example.com
4530 DocumentRoot /www/docs/host.example.com
4531 ServerName host.example.com
4532 ErrorLog logs/host.example.com-error_log
4533 TransferLog logs/host.example.com-access_log
4534 </VirtualHost></pre>
4537 <p>Each Virtual Host must correspond to a different IP address,
4538 different port number or a different host name for the server,
4539 in the former case the server machine must be configured to
4540 accept IP packets for multiple addresses. (If the machine does
4541 not have multiple network interfaces, then this can be
4542 accomplished with the <code>ifconfig alias</code> command -- if
4543 your OS supports it).</p>
4545 <div class="note"><h3>Note</h3>
4546 <p>The use of <code class="directive"><VirtualHost></code> does
4547 <strong>not</strong> affect what addresses Apache httpd listens on. You
4548 may need to ensure that Apache httpd is listening on the correct addresses
4549 using <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>.</p>
4552 <p>A <code class="directive"><a href="#servername">ServerName</a></code> should be
4553 specified inside each <code class="directive"><VirtualHost></code> block. If it is absent, the
4554 <code class="directive"><a href="#servername">ServerName</a></code> from the "main"
4555 server configuration will be inherited.</p>
4557 <p>When a request is received, the server first maps it to the best matching
4558 <code class="directive"><VirtualHost></code> based on the local
4559 IP address and port combination only. Non-wildcards have a higher
4560 precedence. If no match based on IP and port occurs at all, the
4561 "main" server configuration is used.</p>
4563 <p>If multiple virtual hosts contain the best matching IP address and port,
4564 the server selects from these virtual hosts the best match based on the
4565 requested hostname. If no matching name-based virtual host is found,
4566 then the first listed virtual host that matched the IP address will be
4567 used. As a consequence, the first listed virtual host for a given IP address
4568 and port combination is default virtual host for that IP and port
4571 <div class="warning"><h3>Security</h3>
4572 <p>See the <a href="../misc/security_tips.html">security tips</a>
4573 document for details on why your security could be compromised if the
4574 directory where log files are stored is writable by anyone other
4575 than the user that starts the server.</p>
4580 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4581 <li><a href="../dns-caveats.html">Issues Regarding DNS and
4582 Apache HTTP Server</a></li>
4583 <li><a href="../bind.html">Setting
4584 which addresses and ports Apache HTTP Server uses</a></li>
4585 <li><a href="../sections.html">How <Directory>, <Location>
4586 and <Files> sections work</a> for an explanation of how these
4587 different sections are combined when a request is received</li>
4590 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4591 <div class="directive-section"><h2><a name="Warning" id="Warning">Warning</a> <a name="warning" id="warning">Directive</a></h2>
4592 <table class="directive">
4593 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Warn from configuration parsing with a custom message</td></tr>
4594 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Warning <var>message</var></code></td></tr>
4595 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4596 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4597 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4598 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.5 and later</td></tr>
4600 <p>If an issue can be detected from within the configuration, this
4601 directive can be used to generate a custom warning message. The
4602 configuration parsing is not halted. The typical use it to check
4603 whether some user define options are set, and warn if not.</p>
4605 <pre class="prettyprint lang-config"># Example
4606 # tell when ReverseProxy is not set
4607 <IfDefine !ReverseProxy>
4608 Warning "reverse proxy is not started, hope this is okay!"
4611 <IfDefine ReverseProxy>
4612 # define custom proxy configuration
4613 </IfDefine></pre>
4619 <div class="bottomlang">
4620 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
4621 <a href="../en/mod/core.html" title="English"> en </a> |
4622 <a href="../es/mod/core.html" hreflang="es" rel="alternate" title="Español"> es </a> |
4623 <a href="../fr/mod/core.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
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