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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 2.4.13 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>
849 <p>Directory paths <em>may</em> be quoted, if you like, however, it
850 <em>must</em> be quoted if the path contains spaces. This is because a
851 space would otherwise indicate the end of an argument.</p>
854 <p>Be careful with the <var>directory-path</var> arguments:
855 They have to literally match the filesystem path which Apache httpd uses
856 to access the files. Directives applied to a particular
857 <code><Directory></code> will not apply to files accessed from
858 that same directory via a different path, such as via different symbolic
862 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular
863 expressions</a> can also be used, with the addition of the
864 <code>~</code> character. For example:</p>
866 <pre class="prettyprint lang-config"><Directory ~ "^/www/[0-9]{3}">
868 </Directory></pre>
871 <p>would match directories in <code>/www/</code> that consisted of
874 <p>If multiple (non-regular expression) <code class="directive"><Directory></code> sections
875 match the directory (or one of its parents) containing a document,
876 then the directives are applied in the order of shortest match
877 first, interspersed with the directives from the <a href="#accessfilename">.htaccess</a> files. For example,
880 <pre class="prettyprint lang-config"><Directory />
884 <Directory "/home">
885 AllowOverride FileInfo
886 </Directory></pre>
889 <p>for access to the document <code>/home/web/dir/doc.html</code>
893 <li>Apply directive <code>AllowOverride None</code>
894 (disabling <code>.htaccess</code> files).</li>
896 <li>Apply directive <code>AllowOverride FileInfo</code> (for
897 directory <code>/home</code>).</li>
899 <li>Apply any <code>FileInfo</code> directives in
900 <code>/home/.htaccess</code>, <code>/home/web/.htaccess</code> and
901 <code>/home/web/dir/.htaccess</code> in that order.</li>
904 <p>Regular expressions are not considered until after all of the
905 normal sections have been applied. Then all of the regular
906 expressions are tested in the order they appeared in the
907 configuration file. For example, with</p>
909 <pre class="prettyprint lang-config"><Directory ~ "abc$">
910 # ... directives here ...
911 </Directory></pre>
914 <p>the regular expression section won't be considered until after
915 all normal <code class="directive"><Directory></code>s and
916 <code>.htaccess</code> files have been applied. Then the regular
917 expression will match on <code>/home/abc/public_html/abc</code> and
918 the corresponding <code class="directive"><Directory></code> will
921 <p><strong>Note that the default access for
922 <code><Directory /></code> is to permit all access.
923 This means that Apache httpd will serve any file mapped from an URL. It is
924 recommended that you change this with a block such
927 <pre class="prettyprint lang-config"><Directory />
929 </Directory></pre>
932 <p><strong>and then override this for directories you
933 <em>want</em> accessible. See the <a href="../misc/security_tips.html">Security Tips</a> page for more
934 details.</strong></p>
936 <p>The directory sections occur in the <code>httpd.conf</code> file.
937 <code class="directive"><Directory></code> directives
938 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>
942 <li><a href="../sections.html">How <Directory>,
943 <Location> and <Files> sections work</a> for an
944 explanation of how these different sections are combined when a
945 request is received</li>
948 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
949 <div class="directive-section"><h2><a name="DirectoryMatch" id="DirectoryMatch"><DirectoryMatch></a> <a name="directorymatch" id="directorymatch">Directive</a></h2>
950 <table class="directive">
951 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose directives that apply to
952 the contents of file-system directories matching a regular expression.</td></tr>
953 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><DirectoryMatch <var>regex</var>>
954 ... </DirectoryMatch></code></td></tr>
955 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
956 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
957 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
959 <p><code class="directive"><DirectoryMatch></code> and
960 <code></DirectoryMatch></code> are used to enclose a group
961 of directives which will apply only to the named directory (and the files within),
962 the same as <code class="directive"><a href="#directory"><Directory></a></code>.
963 However, it takes as an argument a
964 <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>. For example:</p>
966 <pre class="prettyprint lang-config"><DirectoryMatch "^/www/(.+/)?[0-9]{3}/">
968 </DirectoryMatch></pre>
971 <p>matches directories in <code>/www/</code> (or any subdirectory thereof)
972 that consist of three numbers.</p>
974 <div class="note"><h3>Compatability</h3>
975 Prior to 2.3.9, this directive implicitly applied to sub-directories
976 (like <code class="directive"><a href="#directory"><Directory></a></code>) and
977 could not match the end of line symbol ($). In 2.3.9 and later,
978 only directories that match the expression are affected by the enclosed
982 <div class="note"><h3>Trailing Slash</h3>
983 This directive applies to requests for directories that may or may
984 not end in a trailing slash, so expressions that are anchored to the
985 end of line ($) must be written with care.
988 <p>From 2.4.8 onwards, named groups and backreferences are captured and
989 written to the environment with the corresponding name prefixed with
990 "MATCH_" and in upper case. This allows elements of paths to be referenced
991 from within <a href="../expr.html">expressions</a> and modules like
992 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
993 (unnamed) backreferences are ignored. Use named groups instead.</p>
995 <pre class="prettyprint lang-config"><DirectoryMatch ^/var/www/combined/(?<sitename>[^/]+)>
996 Require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
997 </DirectoryMatch></pre>
1002 <li><code class="directive"><a href="#directory"><Directory></a></code> for
1003 a description of how regular expressions are mixed in with normal
1004 <code class="directive"><Directory></code>s</li>
1005 <li><a href="../sections.html">How <Directory>, <Location> and
1006 <Files> sections work</a> for an explanation of how these different
1007 sections are combined when a request is received</li>
1010 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1011 <div class="directive-section"><h2><a name="DocumentRoot" id="DocumentRoot">DocumentRoot</a> <a name="documentroot" id="documentroot">Directive</a></h2>
1012 <table class="directive">
1013 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory that forms the main document tree visible
1014 from the web</td></tr>
1015 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DocumentRoot <var>directory-path</var></code></td></tr>
1016 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DocumentRoot /usr/local/apache/htdocs</code></td></tr>
1017 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1018 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1019 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1021 <p>This directive sets the directory from which <code class="program"><a href="../programs/httpd.html">httpd</a></code>
1022 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
1023 path from the requested URL to the document root to make the
1024 path to the document. Example:</p>
1026 <pre class="prettyprint lang-config">DocumentRoot "/usr/web"</pre>
1029 <p>then an access to
1030 <code>http://my.example.com/index.html</code> refers to
1031 <code>/usr/web/index.html</code>. If the <var>directory-path</var> is
1032 not absolute then it is assumed to be relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1034 <p>The <code class="directive">DocumentRoot</code> should be specified without
1035 a trailing slash.</p>
1039 <li><a href="../urlmapping.html#documentroot">Mapping URLs to Filesystem
1043 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1044 <div class="directive-section"><h2><a name="Else" id="Else"><Else></a> <a name="else" id="else">Directive</a></h2>
1045 <table class="directive">
1046 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if the condition of a
1047 previous <code class="directive"><a href="#if"><If></a></code> or
1048 <code class="directive"><a href="#elseif"><ElseIf></a></code> section is not
1049 satisfied by a request at runtime</td></tr>
1050 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Else> ... </Else></code></td></tr>
1051 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1052 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1053 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1054 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1056 <p>The <code class="directive"><Else></code> applies the enclosed
1057 directives if and only if the most recent
1058 <code class="directive"><If></code> or
1059 <code class="directive"><ElseIf></code> section
1060 in the same scope has not been applied.
1061 For example: In </p>
1063 <pre class="prettyprint lang-config"><If "-z req('Host')">
1071 <p> The <code class="directive"><If></code> would match HTTP/1.0
1072 requests without a <var>Host:</var> header and the
1073 <code class="directive"><Else></code> would match requests
1074 with a <var>Host:</var> header.</p>
1079 <li><code class="directive"><a href="#if"><If></a></code></li>
1080 <li><code class="directive"><a href="#elseif"><ElseIf></a></code></li>
1081 <li><a href="../sections.html">How <Directory>, <Location>,
1082 <Files> sections work</a> for an explanation of how these
1083 different sections are combined when a request is received.
1084 <code class="directive"><If></code>,
1085 <code class="directive"><ElseIf></code>, and
1086 <code class="directive"><Else></code> are applied last.</li>
1089 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1090 <div class="directive-section"><h2><a name="ElseIf" id="ElseIf"><ElseIf></a> <a name="elseif" id="elseif">Directive</a></h2>
1091 <table class="directive">
1092 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is satisfied
1093 by a request at runtime while the condition of a previous
1094 <code class="directive"><a href="#if"><If></a></code> or
1095 <code class="directive"><ElseIf></code> section is not
1097 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><ElseIf <var>expression</var>> ... </ElseIf></code></td></tr>
1098 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1099 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1100 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1101 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1103 <p>The <code class="directive"><ElseIf></code> applies the enclosed
1104 directives if and only if both the given condition evaluates to true and
1105 the most recent <code class="directive"><If></code> or
1106 <code class="directive"><ElseIf></code> section in the same scope has
1107 not been applied. For example: In </p>
1109 <pre class="prettyprint lang-config"><If "-R '10.1.0.0/16'">
1112 <ElseIf "-R '10.0.0.0/8'">
1120 <p>The <code class="directive"><ElseIf></code> would match if
1121 the remote address of a request belongs to the subnet 10.0.0.0/8 but
1122 not to the subnet 10.1.0.0/16.</p>
1127 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
1128 for a complete reference and more examples.</li>
1129 <li><code class="directive"><a href="#if"><If></a></code></li>
1130 <li><code class="directive"><a href="#else"><Else></a></code></li>
1131 <li><a href="../sections.html">How <Directory>, <Location>,
1132 <Files> sections work</a> for an explanation of how these
1133 different sections are combined when a request is received.
1134 <code class="directive"><If></code>,
1135 <code class="directive"><ElseIf></code>, and
1136 <code class="directive"><Else></code> are applied last.</li>
1139 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1140 <div class="directive-section"><h2><a name="EnableMMAP" id="EnableMMAP">EnableMMAP</a> <a name="enablemmap" id="enablemmap">Directive</a></h2>
1141 <table class="directive">
1142 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use memory-mapping to read files during delivery</td></tr>
1143 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableMMAP On|Off</code></td></tr>
1144 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableMMAP On</code></td></tr>
1145 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1146 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1147 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1148 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1150 <p>This directive controls whether the <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use
1151 memory-mapping if it needs to read the contents of a file during
1152 delivery. By default, when the handling of a request requires
1153 access to the data within a file -- for example, when delivering a
1154 server-parsed file using <code class="module"><a href="../mod/mod_include.html">mod_include</a></code> -- Apache httpd
1155 memory-maps the file if the OS supports it.</p>
1157 <p>This memory-mapping sometimes yields a performance improvement.
1158 But in some environments, it is better to disable the memory-mapping
1159 to prevent operational problems:</p>
1162 <li>On some multiprocessor systems, memory-mapping can reduce the
1163 performance of the <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</li>
1164 <li>Deleting or truncating a file while <code class="program"><a href="../programs/httpd.html">httpd</a></code>
1165 has it memory-mapped can cause <code class="program"><a href="../programs/httpd.html">httpd</a></code> to
1166 crash with a segmentation fault.
1170 <p>For server configurations that are vulnerable to these problems,
1171 you should disable memory-mapping of delivered files by specifying:</p>
1173 <pre class="prettyprint lang-config">EnableMMAP Off</pre>
1176 <p>For NFS mounted files, this feature may be disabled explicitly for
1177 the offending files by specifying:</p>
1179 <pre class="prettyprint lang-config"><Directory "/path-to-nfs-files">
1181 </Directory></pre>
1185 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1186 <div class="directive-section"><h2><a name="EnableSendfile" id="EnableSendfile">EnableSendfile</a> <a name="enablesendfile" id="enablesendfile">Directive</a></h2>
1187 <table class="directive">
1188 <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>
1189 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableSendfile On|Off</code></td></tr>
1190 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableSendfile Off</code></td></tr>
1191 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1192 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1193 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1194 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1195 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Default changed to Off in
1196 version 2.3.9.</td></tr>
1198 <p>This directive controls whether <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use the
1199 sendfile support from the kernel to transmit file contents to the client.
1200 By default, when the handling of a request requires no access
1201 to the data within a file -- for example, when delivering a
1202 static file -- Apache httpd uses sendfile to deliver the file contents
1203 without ever reading the file if the OS supports it.</p>
1205 <p>This sendfile mechanism avoids separate read and send operations,
1206 and buffer allocations. But on some platforms or within some
1207 filesystems, it is better to disable this feature to avoid
1208 operational problems:</p>
1211 <li>Some platforms may have broken sendfile support that the build
1212 system did not detect, especially if the binaries were built on
1213 another box and moved to such a machine with broken sendfile
1215 <li>On Linux the use of sendfile triggers TCP-checksum
1216 offloading bugs on certain networking cards when using IPv6.</li>
1217 <li>On Linux on Itanium, <code>sendfile</code> may be unable to handle
1218 files over 2GB in size.</li>
1219 <li>With a network-mounted <code class="directive"><a href="#documentroot">DocumentRoot</a></code> (e.g., NFS, SMB, CIFS, FUSE),
1220 the kernel may be unable to serve the network file through
1224 <p>For server configurations that are not vulnerable to these problems,
1225 you may enable this feature by specifying:</p>
1227 <pre class="prettyprint lang-config">EnableSendfile On</pre>
1230 <p>For network mounted files, this feature may be disabled explicitly
1231 for the offending files by specifying:</p>
1233 <pre class="prettyprint lang-config"><Directory "/path-to-nfs-files">
1235 </Directory></pre>
1237 <p>Please note that the per-directory and .htaccess configuration
1238 of <code class="directive">EnableSendfile</code> is not supported by
1239 <code class="module"><a href="../mod/mod_cache_disk.html">mod_cache_disk</a></code>.
1240 Only global definition of <code class="directive">EnableSendfile</code>
1241 is taken into account by the module.
1245 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1246 <div class="directive-section"><h2><a name="Error" id="Error">Error</a> <a name="error" id="error">Directive</a></h2>
1247 <table class="directive">
1248 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Abort configuration parsing with a custom error message</td></tr>
1249 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Error <var>message</var></code></td></tr>
1250 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1251 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1252 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1253 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.3.9 and later</td></tr>
1255 <p>If an error can be detected within the configuration, this
1256 directive can be used to generate a custom error message, and halt
1257 configuration parsing. The typical use is for reporting required
1258 modules which are missing from the configuration.</p>
1260 <pre class="prettyprint lang-config"># Example
1261 # ensure that mod_include is loaded
1262 <IfModule !include_module>
1263 Error "mod_include is required by mod_foo. Load it with LoadModule."
1266 # ensure that exactly one of SSL,NOSSL is defined
1267 <IfDefine SSL>
1268 <IfDefine NOSSL>
1269 Error "Both SSL and NOSSL are defined. Define only one of them."
1272 <IfDefine !SSL>
1273 <IfDefine !NOSSL>
1274 Error "Either SSL or NOSSL must be defined."
1276 </IfDefine></pre>
1281 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1282 <div class="directive-section"><h2><a name="ErrorDocument" id="ErrorDocument">ErrorDocument</a> <a name="errordocument" id="errordocument">Directive</a></h2>
1283 <table class="directive">
1284 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>What the server will return to the client
1285 in case of an error</td></tr>
1286 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ErrorDocument <var>error-code</var> <var>document</var></code></td></tr>
1287 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1288 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1289 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1290 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1292 <p>In the event of a problem or error, Apache httpd can be configured
1293 to do one of four things,</p>
1296 <li>output a simple hardcoded error message</li>
1298 <li>output a customized message</li>
1300 <li>internally redirect to a local <var>URL-path</var> to handle the
1303 <li>redirect to an external <var>URL</var> to handle the
1307 <p>The first option is the default, while options 2-4 are
1308 configured using the <code class="directive">ErrorDocument</code>
1309 directive, which is followed by the HTTP response code and a URL
1310 or a message. Apache httpd will sometimes offer additional information
1311 regarding the problem/error.</p>
1313 <p>From 2.4.13, <a href="../expr.html">expression syntax</a> can be
1314 used inside the directive to produce dynamic strings and URLs.</p>
1316 <p>URLs can begin with a slash (/) for local web-paths (relative
1317 to the <code class="directive"><a href="#documentroot">DocumentRoot</a></code>), or be a
1318 full URL which the client can resolve. Alternatively, a message
1319 can be provided to be displayed by the browser. Note that deciding
1320 whether the parameter is an URL, a path or a message is performed
1321 before any expression is parsed. Examples:</p>
1323 <pre class="prettyprint lang-config">ErrorDocument 500 http://foo.example.com/cgi-bin/tester
1324 ErrorDocument 404 /cgi-bin/bad_urls.pl
1325 ErrorDocument 401 /subscription_info.html
1326 ErrorDocument 403 "Sorry can't allow you access today"
1327 ErrorDocument 403 Forbidden!
1328 ErrorDocument 403 /cgi-bin/forbidden.pl?referrer=%{escape:%{HTTP_REFERER}}</pre>
1331 <p>Additionally, the special value <code>default</code> can be used
1332 to specify Apache httpd's simple hardcoded message. While not required
1333 under normal circumstances, <code>default</code> will restore
1334 Apache httpd's simple hardcoded message for configurations that would
1335 otherwise inherit an existing <code class="directive">ErrorDocument</code>.</p>
1337 <pre class="prettyprint lang-config">ErrorDocument 404 /cgi-bin/bad_urls.pl
1339 <Directory /web/docs>
1340 ErrorDocument 404 default
1341 </Directory></pre>
1344 <p>Note that when you specify an <code class="directive">ErrorDocument</code>
1345 that points to a remote URL (ie. anything with a method such as
1346 <code>http</code> in front of it), Apache HTTP Server will send a redirect to the
1347 client to tell it where to find the document, even if the
1348 document ends up being on the same server. This has several
1349 implications, the most important being that the client will not
1350 receive the original error status code, but instead will
1351 receive a redirect status code. This in turn can confuse web
1352 robots and other clients which try to determine if a URL is
1353 valid using the status code. In addition, if you use a remote
1354 URL in an <code>ErrorDocument 401</code>, the client will not
1355 know to prompt the user for a password since it will not
1356 receive the 401 status code. Therefore, <strong>if you use an
1357 <code>ErrorDocument 401</code> directive then it must refer to a local
1358 document.</strong></p>
1360 <p>Microsoft Internet Explorer (MSIE) will by default ignore
1361 server-generated error messages when they are "too small" and substitute
1362 its own "friendly" error messages. The size threshold varies depending on
1363 the type of error, but in general, if you make your error document
1364 greater than 512 bytes, then MSIE will show the server-generated
1365 error rather than masking it. More information is available in
1366 Microsoft Knowledge Base article <a href="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q294807">Q294807</a>.</p>
1368 <p>Although most error messages can be overridden, there are certain
1369 circumstances where the internal messages are used regardless of the
1370 setting of <code class="directive"><a href="#errordocument">ErrorDocument</a></code>. In
1371 particular, if a malformed request is detected, normal request processing
1372 will be immediately halted and the internal error message returned.
1373 This is necessary to guard against security problems caused by
1376 <p>If you are using mod_proxy, you may wish to enable
1377 <code class="directive"><a href="../mod/mod_proxy.html#proxyerroroverride">ProxyErrorOverride</a></code> so that you can provide
1378 custom error messages on behalf of your Origin servers. If you don't enable ProxyErrorOverride,
1379 Apache httpd will not generate custom error documents for proxied content.</p>
1383 <li><a href="../custom-error.html">documentation of
1384 customizable responses</a></li>
1387 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1388 <div class="directive-section"><h2><a name="ErrorLog" id="ErrorLog">ErrorLog</a> <a name="errorlog" id="errorlog">Directive</a></h2>
1389 <table class="directive">
1390 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Location where the server will log errors</td></tr>
1391 <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>
1392 <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>
1393 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1394 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1395 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1397 <p>The <code class="directive">ErrorLog</code> directive sets the name of
1398 the file to which the server will log any errors it encounters. If
1399 the <var>file-path</var> is not absolute then it is assumed to be
1400 relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1402 <pre class="prettyprint lang-config">ErrorLog "/var/log/httpd/error_log"</pre>
1405 <p>If the <var>file-path</var>
1406 begins with a pipe character "<code>|</code>" then it is assumed to be a
1407 command to spawn to handle the error log.</p>
1409 <pre class="prettyprint lang-config">ErrorLog "|/usr/local/bin/httpd_errors"</pre>
1412 <p>See the notes on <a href="../logs.html#piped">piped logs</a> for
1413 more information.</p>
1415 <p>Using <code>syslog</code> instead of a filename enables logging
1416 via syslogd(8) if the system supports it and if <code class="module"><a href="../mod/mod_syslog.html">mod_syslog</a></code>
1417 is loaded. The default is to use syslog facility <code>local7</code>,
1418 but you can override this by using the <code>syslog:<var>facility</var></code>
1419 syntax where <var>facility</var> can be one of the names usually documented in
1420 syslog(1). The facility is effectively global, and if it is changed
1421 in individual virtual hosts, the final facility specified affects the
1424 <pre class="prettyprint lang-config">ErrorLog syslog:user</pre>
1427 <p>Additional modules can provide their own ErrorLog providers. The syntax
1428 is similar to <code>syslog</code> example above.</p>
1430 <p>SECURITY: See the <a href="../misc/security_tips.html#serverroot">security tips</a>
1431 document for details on why your security could be compromised
1432 if the directory where log files are stored is writable by
1433 anyone other than the user that starts the server.</p>
1434 <div class="warning"><h3>Note</h3>
1435 <p>When entering a file path on non-Unix platforms, care should be taken
1436 to make sure that only forward slashes are used even though the platform
1437 may allow the use of back slashes. In general it is a good idea to always
1438 use forward slashes throughout the configuration files.</p>
1443 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1444 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1447 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1448 <div class="directive-section"><h2><a name="ErrorLogFormat" id="ErrorLogFormat">ErrorLogFormat</a> <a name="errorlogformat" id="errorlogformat">Directive</a></h2>
1449 <table class="directive">
1450 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Format specification for error log entries</td></tr>
1451 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code> ErrorLogFormat [connection|request] <var>format</var></code></td></tr>
1452 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1453 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1454 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1456 <p><code class="directive">ErrorLogFormat</code> allows to specify what
1457 supplementary information is logged in the error log in addition to the
1458 actual log message.</p>
1460 <pre class="prettyprint lang-config">#Simple example
1461 ErrorLogFormat "[%t] [%l] [pid %P] %F: %E: [client %a] %M"</pre>
1464 <p>Specifying <code>connection</code> or <code>request</code> as first
1465 parameter allows to specify additional formats, causing additional
1466 information to be logged when the first message is logged for a specific
1467 connection or request, respectively. This additional information is only
1468 logged once per connection/request. If a connection or request is processed
1469 without causing any log message, the additional information is not logged
1472 <p>It can happen that some format string items do not produce output. For
1473 example, the Referer header is only present if the log message is
1474 associated to a request and the log message happens at a time when the
1475 Referer header has already been read from the client. If no output is
1476 produced, the default behavior is to delete everything from the preceding
1477 space character to the next space character. This means the log line is
1478 implicitly divided into fields on non-whitespace to whitespace transitions.
1479 If a format string item does not produce output, the whole field is
1480 omitted. For example, if the remote address <code>%a</code> in the log
1481 format <code>[%t] [%l] [%a] %M </code> is not available, the surrounding
1482 brackets are not logged either. Space characters can be escaped with a
1483 backslash to prevent them from delimiting a field. The combination '% '
1484 (percent space) is a zero-width field delimiter that does not produce any
1487 <p>The above behavior can be changed by adding modifiers to the format
1488 string item. A <code>-</code> (minus) modifier causes a minus to be logged if the
1489 respective item does not produce any output. In once-per-connection/request
1490 formats, it is also possible to use the <code>+</code> (plus) modifier. If an
1491 item with the plus modifier does not produce any output, the whole line is
1494 <p>A number as modifier can be used to assign a log severity level to a
1495 format item. The item will only be logged if the severity of the log
1496 message is not higher than the specified log severity level. The number can
1497 range from 1 (alert) over 4 (warn) and 7 (debug) to 15 (trace8).</p>
1499 <p>For example, here's what would happen if you added modifiers to
1500 the <code>%{Referer}i</code> token, which logs the
1501 <code>Referer</code> request header.</p>
1503 <table class="bordered"><tr class="header"><th>Modified Token</th><th>Meaning</th></tr>
1505 <td><code>%-{Referer}i</code></td>
1506 <td>Logs a <code>-</code> if <code>Referer</code> is not set.</td>
1509 <td><code>%+{Referer}i</code></td>
1510 <td>Omits the entire line if <code>Referer</code> is not set.</td>
1513 <td><code>%4{Referer}i</code></td>
1514 <td>Logs the <code>Referer</code> only if the log message severity
1515 is higher than 4.</td>
1519 <p>Some format string items accept additional parameters in braces.</p>
1521 <table class="bordered"><tr class="header"><th>Format String</th> <th>Description</th></tr>
1522 <tr><td><code>%%</code></td>
1523 <td>The percent sign</td></tr>
1524 <tr class="odd"><td><code>%a</code></td>
1525 <td>Client IP address and port of the request</td></tr>
1526 <tr><td><code>%{c}a</code></td>
1527 <td>Underlying peer IP address and port of the connection (see the
1528 <code class="module"><a href="../mod/mod_remoteip.html">mod_remoteip</a></code> module)</td></tr>
1529 <tr class="odd"><td><code>%A</code></td>
1530 <td>Local IP-address and port</td></tr>
1531 <tr><td><code>%{<em>name</em>}e</code></td>
1532 <td>Request environment variable <em>name</em></td></tr>
1533 <tr class="odd"><td><code>%E</code></td>
1534 <td>APR/OS error status code and string</td></tr>
1535 <tr><td><code>%F</code></td>
1536 <td>Source file name and line number of the log call</td></tr>
1537 <tr class="odd"><td><code>%{<em>name</em>}i</code></td>
1538 <td>Request header <em>name</em></td></tr>
1539 <tr><td><code>%k</code></td>
1540 <td>Number of keep-alive requests on this connection</td></tr>
1541 <tr class="odd"><td><code>%l</code></td>
1542 <td>Loglevel of the message</td></tr>
1543 <tr><td><code>%L</code></td>
1544 <td>Log ID of the request</td></tr>
1545 <tr class="odd"><td><code>%{c}L</code></td>
1546 <td>Log ID of the connection</td></tr>
1547 <tr><td><code>%{C}L</code></td>
1548 <td>Log ID of the connection if used in connection scope, empty otherwise</td></tr>
1549 <tr class="odd"><td><code>%m</code></td>
1550 <td>Name of the module logging the message</td></tr>
1551 <tr><td><code>%M</code></td>
1552 <td>The actual log message</td></tr>
1553 <tr class="odd"><td><code>%{<em>name</em>}n</code></td>
1554 <td>Request note <em>name</em></td></tr>
1555 <tr><td><code>%P</code></td>
1556 <td>Process ID of current process</td></tr>
1557 <tr class="odd"><td><code>%T</code></td>
1558 <td>Thread ID of current thread</td></tr>
1559 <tr><td><code>%{g}T</code></td>
1560 <td>System unique thread ID of current thread (the same ID as
1561 displayed by e.g. <code>top</code>; currently Linux only)</td></tr>
1562 <tr class="odd"><td><code>%t</code></td>
1563 <td>The current time</td></tr>
1564 <tr><td><code>%{u}t</code></td>
1565 <td>The current time including micro-seconds</td></tr>
1566 <tr class="odd"><td><code>%{cu}t</code></td>
1567 <td>The current time in compact ISO 8601 format, including
1568 micro-seconds</td></tr>
1569 <tr><td><code>%v</code></td>
1570 <td>The canonical <code class="directive"><a href="#servername">ServerName</a></code>
1571 of the current server.</td></tr>
1572 <tr class="odd"><td><code>%V</code></td>
1573 <td>The server name of the server serving the request according to the
1574 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code>
1576 <tr><td><code>\ </code> (backslash space)</td>
1577 <td>Non-field delimiting space</td></tr>
1578 <tr class="odd"><td><code>% </code> (percent space)</td>
1579 <td>Field delimiter (no output)</td></tr>
1582 <p>The log ID format <code>%L</code> produces a unique id for a connection
1583 or request. This can be used to correlate which log lines belong to the
1584 same connection or request, which request happens on which connection.
1585 A <code>%L</code> format string is also available in
1586 <code class="module"><a href="../mod/mod_log_config.html">mod_log_config</a></code>, to allow to correlate access log entries
1587 with error log lines. If <code class="module"><a href="../mod/mod_unique_id.html">mod_unique_id</a></code> is loaded, its
1588 unique id will be used as log ID for requests.</p>
1590 <pre class="prettyprint lang-config">#Example (default format for threaded MPMs)
1591 ErrorLogFormat "[%{u}t] [%-m:%l] [pid %P:tid %T] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"</pre>
1594 <p>This would result in error messages such as:</p>
1596 <div class="example"><p><code>
1597 [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
1600 <p>Notice that, as discussed above, some fields are omitted
1601 entirely because they are not defined.</p>
1603 <pre class="prettyprint lang-config">#Example (similar to the 2.2.x format)
1604 ErrorLogFormat "[%t] [%l] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"</pre>
1607 <pre class="prettyprint lang-config">#Advanced example with request/connection log IDs
1608 ErrorLogFormat "[%{uc}t] [%-m:%-l] [R:%L] [C:%{C}L] %7F: %E: %M"
1609 ErrorLogFormat request "[%{uc}t] [R:%L] Request %k on C:%{c}L pid:%P tid:%T"
1610 ErrorLogFormat request "[%{uc}t] [R:%L] UA:'%+{User-Agent}i'"
1611 ErrorLogFormat request "[%{uc}t] [R:%L] Referer:'%+{Referer}i'"
1612 ErrorLogFormat connection "[%{uc}t] [C:%{c}L] local\ %a remote\ %A"</pre>
1618 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
1619 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1620 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1623 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1624 <div class="directive-section"><h2><a name="ExtendedStatus" id="ExtendedStatus">ExtendedStatus</a> <a name="extendedstatus" id="extendedstatus">Directive</a></h2>
1625 <table class="directive">
1626 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Keep track of extended status information for each
1628 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ExtendedStatus On|Off</code></td></tr>
1629 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ExtendedStatus Off[*]</code></td></tr>
1630 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
1631 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1632 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1634 <p>This option tracks additional data per worker about the
1635 currently executing request, and a utilization summary; you
1636 can see these variables during runtime by configuring
1637 <code class="module"><a href="../mod/mod_status.html">mod_status</a></code>. Note that other modules may
1638 rely on this scoreboard.</p>
1640 <p>This setting applies to the entire server, and cannot be
1641 enabled or disabled on a virtualhost-by-virtualhost basis.
1642 The collection of extended status information can slow down
1643 the server. Also note that this setting cannot be changed
1644 during a graceful restart.</p>
1647 <p>Note that loading <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> will change
1648 the default behavior to ExtendedStatus On, while other
1649 third party modules may do the same. Such modules rely on
1650 collecting detailed information about the state of all workers.
1651 The default is changed by <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> beginning
1652 with version 2.3.6; the previous default was always Off.</p>
1657 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1658 <div class="directive-section"><h2><a name="FileETag" id="FileETag">FileETag</a> <a name="fileetag" id="fileetag">Directive</a></h2>
1659 <table class="directive">
1660 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>File attributes used to create the ETag
1661 HTTP response header for static files</td></tr>
1662 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>FileETag <var>component</var> ...</code></td></tr>
1663 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>FileETag MTime Size</code></td></tr>
1664 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1665 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1666 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1667 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1668 <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
1672 The <code class="directive">FileETag</code> directive configures the file
1673 attributes that are used to create the <code>ETag</code> (entity
1674 tag) response header field when the document is based on a static file.
1675 (The <code>ETag</code> value is used in cache management to save
1676 network bandwidth.) The
1677 <code class="directive">FileETag</code> directive allows you to choose
1678 which of these -- if any -- should be used. The recognized keywords are:
1682 <dt><strong>INode</strong></dt>
1683 <dd>The file's i-node number will be included in the calculation</dd>
1684 <dt><strong>MTime</strong></dt>
1685 <dd>The date and time the file was last modified will be included</dd>
1686 <dt><strong>Size</strong></dt>
1687 <dd>The number of bytes in the file will be included</dd>
1688 <dt><strong>All</strong></dt>
1689 <dd>All available fields will be used. This is equivalent to:
1690 <pre class="prettyprint lang-config">FileETag INode MTime Size</pre>
1692 <dt><strong>None</strong></dt>
1693 <dd>If a document is file-based, no <code>ETag</code> field will be
1694 included in the response</dd>
1697 <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
1698 keywords may be prefixed with either <code>+</code> or <code>-</code>,
1699 which allow changes to be made to the default setting inherited
1700 from a broader scope. Any keyword appearing without such a prefix
1701 immediately and completely cancels the inherited setting.</p>
1703 <p>If a directory's configuration includes
1704 <code>FileETag INode MTime Size</code>, and a
1705 subdirectory's includes <code>FileETag -INode</code>,
1706 the setting for that subdirectory (which will be inherited by
1707 any sub-subdirectories that don't override it) will be equivalent to
1708 <code>FileETag MTime Size</code>.</p>
1709 <div class="warning"><h3>Warning</h3>
1710 Do not change the default for directories or locations that have WebDAV
1711 enabled and use <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> as a storage provider.
1712 <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> uses <code>MTime Size</code>
1713 as a fixed format for <code>ETag</code> comparisons on conditional requests.
1714 These conditional requests will break if the <code>ETag</code> format is
1715 changed via <code class="directive">FileETag</code>.
1717 <div class="note"><h3>Server Side Includes</h3>
1718 An ETag is not generated for responses parsed by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>,
1719 since the response entity can change without a change of the INode, MTime, or Size
1720 of the static file with embedded SSI directives.
1725 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1726 <div class="directive-section"><h2><a name="Files" id="Files"><Files></a> <a name="files" id="files">Directive</a></h2>
1727 <table class="directive">
1728 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to matched
1730 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Files <var>filename</var>> ... </Files></code></td></tr>
1731 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1732 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1733 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1734 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1736 <p>The <code class="directive"><Files></code> directive
1737 limits the scope of the enclosed directives by filename. It is comparable
1738 to the <code class="directive"><a href="#directory"><Directory></a></code>
1739 and <code class="directive"><a href="#location"><Location></a></code>
1740 directives. It should be matched with a <code></Files></code>
1741 directive. The directives given within this section will be applied to
1742 any object with a basename (last component of filename) matching the
1743 specified filename. <code class="directive"><Files></code>
1744 sections are processed in the order they appear in the
1745 configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
1746 <code>.htaccess</code> files are read, but before <code class="directive"><a href="#location"><Location></a></code> sections. Note
1747 that <code class="directive"><Files></code> can be nested
1748 inside <code class="directive"><a href="#directory"><Directory></a></code> sections to restrict the
1749 portion of the filesystem they apply to.</p>
1751 <p>The <var>filename</var> argument should include a filename, or
1752 a wild-card string, where <code>?</code> matches any single character,
1753 and <code>*</code> matches any sequences of characters.</p>
1754 <pre class="prettyprint lang-config"><Files "cat.html">
1755 # Insert stuff that applies to cat.html here
1758 <Files "?at.*">
1759 # This would apply to cat.html, bat.html, hat.php and so on.
1760 </Files></pre>
1762 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
1763 can also be used, with the addition of the
1764 <code>~</code> character. For example:</p>
1766 <pre class="prettyprint lang-config"><Files ~ "\.(gif|jpe?g|png)$">
1768 </Files></pre>
1771 <p>would match most common Internet graphics formats. <code class="directive"><a href="#filesmatch"><FilesMatch></a></code> is preferred,
1774 <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
1775 <code>.htaccess</code> files. This allows users to control access to
1776 their own files, at a file-by-file level.</p>
1781 <li><a href="../sections.html">How <Directory>, <Location>
1782 and <Files> sections work</a> for an explanation of how these
1783 different sections are combined when a request is received</li>
1786 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1787 <div class="directive-section"><h2><a name="FilesMatch" id="FilesMatch"><FilesMatch></a> <a name="filesmatch" id="filesmatch">Directive</a></h2>
1788 <table class="directive">
1789 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to regular-expression matched
1791 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><FilesMatch <var>regex</var>> ... </FilesMatch></code></td></tr>
1792 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1793 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1794 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1795 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1797 <p>The <code class="directive"><FilesMatch></code> directive
1798 limits the scope of the enclosed directives by filename, just as the
1799 <code class="directive"><a href="#files"><Files></a></code> directive
1800 does. However, it accepts a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular
1801 expression</a>. For example:</p>
1803 <pre class="prettyprint lang-config"><FilesMatch ".+\.(gif|jpe?g|png)$">
1805 </FilesMatch></pre>
1808 <p>would match most common Internet graphics formats.</p>
1810 <div class="note">The <code>.+</code> at the start of the regex ensures that
1811 files named <code>.png</code>, or <code>.gif</code>, for example,
1812 are not matched.</div>
1814 <p>From 2.4.8 onwards, named groups and backreferences are captured and
1815 written to the environment with the corresponding name prefixed with
1816 "MATCH_" and in upper case. This allows elements of files to be referenced
1817 from within <a href="../expr.html">expressions</a> and modules like
1818 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
1819 (unnamed) backreferences are ignored. Use named groups instead.</p>
1821 <pre class="prettyprint lang-config"><FilesMatch ^(?<sitename>[^/]+)>
1822 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
1823 </FilesMatch></pre>
1828 <li><a href="../sections.html">How <Directory>, <Location>
1829 and <Files> sections work</a> for an explanation of how these
1830 different sections are combined when a request is received</li>
1833 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1834 <div class="directive-section"><h2><a name="ForceType" id="ForceType">ForceType</a> <a name="forcetype" id="forcetype">Directive</a></h2>
1835 <table class="directive">
1836 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be served with the specified
1837 media type in the HTTP Content-Type header field</td></tr>
1838 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ForceType <var>media-type</var>|None</code></td></tr>
1839 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
1840 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1841 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1842 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1844 <p>When placed into an <code>.htaccess</code> file or a
1845 <code class="directive"><a href="#directory"><Directory></a></code>, or
1846 <code class="directive"><a href="#location"><Location></a></code> or
1847 <code class="directive"><a href="#files"><Files></a></code>
1848 section, this directive forces all matching files to be served
1849 with the content type identification given by
1850 <var>media-type</var>. For example, if you had a directory full of
1851 GIF files, but did not want to label them all with <code>.gif</code>,
1852 you might want to use:</p>
1854 <pre class="prettyprint lang-config">ForceType image/gif</pre>
1857 <p>Note that this directive overrides other indirect media type
1858 associations defined in mime.types or via the
1859 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code>.</p>
1861 <p>You can also override more general
1862 <code class="directive">ForceType</code> settings
1863 by using the value of <code>None</code>:</p>
1865 <pre class="prettyprint lang-config"># force all files to be image/gif:
1866 <Location /images>
1870 # but normal mime-type associations here:
1871 <Location /images/mixed>
1873 </Location></pre>
1876 <p>This directive primarily overrides the content types generated for
1877 static files served out of the filesystem. For resources other than
1878 static files, where the generator of the response typically specifies
1879 a Content-Type, this directive has no effect.</p>
1883 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1884 <div class="directive-section"><h2><a name="GprofDir" id="GprofDir">GprofDir</a> <a name="gprofdir" id="gprofdir">Directive</a></h2>
1885 <table class="directive">
1886 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory to write gmon.out profiling data to. </td></tr>
1887 <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>
1888 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1889 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1890 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1892 <p>When the server has been compiled with gprof profiling support,
1893 <code class="directive">GprofDir</code> causes <code>gmon.out</code> files to
1894 be written to the specified directory when the process exits. If the
1895 argument ends with a percent symbol ('%'), subdirectories are created
1896 for each process id.</p>
1898 <p>This directive currently only works with the <code class="module"><a href="../mod/prefork.html">prefork</a></code>
1902 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1903 <div class="directive-section"><h2><a name="HostnameLookups" id="HostnameLookups">HostnameLookups</a> <a name="hostnamelookups" id="hostnamelookups">Directive</a></h2>
1904 <table class="directive">
1905 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables DNS lookups on client IP addresses</td></tr>
1906 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>HostnameLookups On|Off|Double</code></td></tr>
1907 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>HostnameLookups Off</code></td></tr>
1908 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1909 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1910 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1912 <p>This directive enables DNS lookups so that host names can be
1913 logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
1914 The value <code>Double</code> refers to doing double-reverse
1915 DNS lookup. That is, after a reverse lookup is performed, a forward
1916 lookup is then performed on that result. At least one of the IP
1917 addresses in the forward lookup must match the original
1918 address. (In "tcpwrappers" terminology this is called
1919 <code>PARANOID</code>.)</p>
1921 <p>Regardless of the setting, when <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code> is
1922 used for controlling access by hostname, a double reverse lookup
1923 will be performed. This is necessary for security. Note that the
1924 result of this double-reverse isn't generally available unless you
1925 set <code>HostnameLookups Double</code>. For example, if only
1926 <code>HostnameLookups On</code> and a request is made to an object
1927 that is protected by hostname restrictions, regardless of whether
1928 the double-reverse fails or not, CGIs will still be passed the
1929 single-reverse result in <code>REMOTE_HOST</code>.</p>
1931 <p>The default is <code>Off</code> in order to save the network
1932 traffic for those sites that don't truly need the reverse
1933 lookups done. It is also better for the end users because they
1934 don't have to suffer the extra latency that a lookup entails.
1935 Heavily loaded sites should leave this directive
1936 <code>Off</code>, since DNS lookups can take considerable
1937 amounts of time. The utility <code class="program"><a href="../programs/logresolve.html">logresolve</a></code>, compiled by
1938 default to the <code>bin</code> subdirectory of your installation
1939 directory, can be used to look up host names from logged IP addresses
1942 <p>Finally, if you have <a href="mod_authz_host.html#reqhost">hostname-based Require
1943 directives</a>, a hostname lookup will be performed regardless of
1944 the setting of <code>HostnameLookups</code>.</p>
1947 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1948 <div class="directive-section"><h2><a name="If" id="If"><If></a> <a name="if" id="if">Directive</a></h2>
1949 <table class="directive">
1950 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is
1951 satisfied by a request at runtime</td></tr>
1952 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><If <var>expression</var>> ... </If></code></td></tr>
1953 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1954 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1955 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1956 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1958 <p>The <code class="directive"><If></code> directive
1959 evaluates an expression at runtime, and applies the enclosed
1960 directives if and only if the expression evaluates to true.
1963 <pre class="prettyprint lang-config"><If "-z req('Host')"></pre>
1966 <p>would match HTTP/1.0 requests without a <var>Host:</var> header.
1967 Expressions may contain various shell-like operators for string
1968 comparison (<code>==</code>, <code>!=</code>, <code><</code>, ...),
1969 integer comparison (<code>-eq</code>, <code>-ne</code>, ...),
1970 and others (<code>-n</code>, <code>-z</code>, <code>-f</code>, ...).
1971 It is also possible to use regular expressions, </p>
1973 <pre class="prettyprint lang-config"><If "%{QUERY_STRING} =~ /(delete|commit)=.*?elem/"></pre>
1976 <p>shell-like pattern matches and many other operations. These operations
1977 can be done on request headers (<code>req</code>), environment variables
1978 (<code>env</code>), and a large number of other properties. The full
1979 documentation is available in <a href="../expr.html">Expressions in
1980 Apache HTTP Server</a>.</p>
1982 <p>Only directives that support the <a href="directive-dict.html#Context">directory context</a> can be used within this configuration section.</p>
1984 <div class="warning">
1985 Certain variables, such as <code>CONTENT_TYPE</code> and other
1986 response headers, are set after <If> conditions have already
1987 been evaluated, and so will not be available to use in this
1994 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
1995 for a complete reference and more examples.</li>
1996 <li><code class="directive"><a href="#elseif"><ElseIf></a></code></li>
1997 <li><code class="directive"><a href="#else"><Else></a></code></li>
1998 <li><a href="../sections.html">How <Directory>, <Location>,
1999 <Files> sections work</a> for an explanation of how these
2000 different sections are combined when a request is received.
2001 <code class="directive"><If></code>,
2002 <code class="directive"><ElseIf></code>, and
2003 <code class="directive"><Else></code> are applied last.</li>
2006 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2007 <div class="directive-section"><h2><a name="IfDefine" id="IfDefine"><IfDefine></a> <a name="ifdefine" id="ifdefine">Directive</a></h2>
2008 <table class="directive">
2009 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that will be processed only
2010 if a test is true at startup</td></tr>
2011 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfDefine [!]<var>parameter-name</var>> ...
2012 </IfDefine></code></td></tr>
2013 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2014 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2015 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2016 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2018 <p>The <code><IfDefine <var>test</var>>...</IfDefine>
2019 </code> section is used to mark directives that are conditional. The
2020 directives within an <code class="directive"><IfDefine></code>
2021 section are only processed if the <var>test</var> is true. If <var>
2022 test</var> is false, everything between the start and end markers is
2025 <p>The <var>test</var> in the <code class="directive"><IfDefine></code> section directive can be one of two forms:</p>
2028 <li><var>parameter-name</var></li>
2030 <li><code>!</code><var>parameter-name</var></li>
2033 <p>In the former case, the directives between the start and end
2034 markers are only processed if the parameter named
2035 <var>parameter-name</var> is defined. The second format reverses
2036 the test, and only processes the directives if
2037 <var>parameter-name</var> is <strong>not</strong> defined.</p>
2039 <p>The <var>parameter-name</var> argument is a define as given on the
2040 <code class="program"><a href="../programs/httpd.html">httpd</a></code> command line via <code>-D<var>parameter</var>
2041 </code> at the time the server was started or by the <code class="directive"><a href="#define">Define</a></code> directive.</p>
2043 <p><code class="directive"><IfDefine></code> sections are
2044 nest-able, which can be used to implement simple
2045 multiple-parameter tests. Example:</p>
2047 <div class="example"><p><code>httpd -DReverseProxy -DUseCache -DMemCache ...</code></p></div>
2048 <pre class="prettyprint lang-config"><IfDefine ReverseProxy>
2049 LoadModule proxy_module modules/mod_proxy.so
2050 LoadModule proxy_http_module modules/mod_proxy_http.so
2051 <IfDefine UseCache>
2052 LoadModule cache_module modules/mod_cache.so
2053 <IfDefine MemCache>
2054 LoadModule mem_cache_module modules/mod_mem_cache.so
2056 <IfDefine !MemCache>
2057 LoadModule cache_disk_module modules/mod_cache_disk.so
2060 </IfDefine></pre>
2064 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2065 <div class="directive-section"><h2><a name="IfModule" id="IfModule"><IfModule></a> <a name="ifmodule" id="ifmodule">Directive</a></h2>
2066 <table class="directive">
2067 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that are processed conditional on the
2068 presence or absence of a specific module</td></tr>
2069 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfModule [!]<var>module-file</var>|<var>module-identifier</var>> ...
2070 </IfModule></code></td></tr>
2071 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2072 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2073 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2074 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2076 <p>The <code><IfModule <var>test</var>>...</IfModule></code>
2077 section is used to mark directives that are conditional on the presence of
2078 a specific module. The directives within an <code class="directive"><IfModule></code> section are only processed if the <var>test</var>
2079 is true. If <var>test</var> is false, everything between the start and
2080 end markers is ignored.</p>
2082 <p>The <var>test</var> in the <code class="directive"><IfModule></code> section directive can be one of two forms:</p>
2085 <li><var>module</var></li>
2087 <li>!<var>module</var></li>
2090 <p>In the former case, the directives between the start and end
2091 markers are only processed if the module named <var>module</var>
2092 is included in Apache httpd -- either compiled in or
2093 dynamically loaded using <code class="directive"><a href="../mod/mod_so.html#loadmodule">LoadModule</a></code>. The second format reverses the test,
2094 and only processes the directives if <var>module</var> is
2095 <strong>not</strong> included.</p>
2097 <p>The <var>module</var> argument can be either the module identifier or
2098 the file name of the module, at the time it was compiled. For example,
2099 <code>rewrite_module</code> is the identifier and
2100 <code>mod_rewrite.c</code> is the file name. If a module consists of
2101 several source files, use the name of the file containing the string
2102 <code>STANDARD20_MODULE_STUFF</code>.</p>
2104 <p><code class="directive"><IfModule></code> sections are
2105 nest-able, which can be used to implement simple multiple-module
2108 <div class="note">This section should only be used if you need to have one
2109 configuration file that works whether or not a specific module
2110 is available. In normal operation, directives need not be
2111 placed in <code class="directive"><IfModule></code>
2115 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2116 <div class="directive-section"><h2><a name="Include" id="Include">Include</a> <a name="include" id="include">Directive</a></h2>
2117 <table class="directive">
2118 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2119 the server configuration files</td></tr>
2120 <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>
2121 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2122 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2123 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2124 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Directory
2125 wildcard matching available in 2.3.6 and later</td></tr>
2127 <p>This directive allows inclusion of other configuration files
2128 from within the server configuration files.</p>
2130 <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used
2131 in the filename or directory parts of the path to include several files
2132 at once, in alphabetical order. In addition, if
2133 <code class="directive">Include</code> points to a directory, rather than a file,
2134 Apache httpd will read all files in that directory and any subdirectory.
2135 However, including entire directories is not recommended, because it is
2136 easy to accidentally leave temporary files in a directory that can cause
2137 <code class="program"><a href="../programs/httpd.html">httpd</a></code> to fail. Instead, we encourage you to use the
2138 wildcard syntax shown below, to include files that match a particular
2139 pattern, such as *.conf, for example.</p>
2141 <p>The <code class="directive"><a href="#include">Include</a></code> directive will
2142 <strong>fail with an error</strong> if a wildcard expression does not
2143 match any file. The <code class="directive"><a href="#includeoptional">IncludeOptional</a></code>
2144 directive can be used if non-matching wildcards should be ignored.</p>
2146 <p>The file path specified may be an absolute path, or may be relative
2147 to the <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory.</p>
2151 <pre class="prettyprint lang-config">Include /usr/local/apache2/conf/ssl.conf
2152 Include /usr/local/apache2/conf/vhosts/*.conf</pre>
2155 <p>Or, providing paths relative to your <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory:</p>
2157 <pre class="prettyprint lang-config">Include conf/ssl.conf
2158 Include conf/vhosts/*.conf</pre>
2161 <p>Wildcards may be included in the directory or file portion of the
2162 path. This example will fail if there is no subdirectory in conf/vhosts
2163 that contains at least one *.conf file:</p>
2165 <pre class="prettyprint lang-config">Include conf/vhosts/*/*.conf</pre>
2168 <p>Alternatively, the following command will just be ignored in case of
2169 missing files or directories:</p>
2171 <pre class="prettyprint lang-config">IncludeOptional conf/vhosts/*/*.conf</pre>
2177 <li><code class="directive"><a href="#includeoptional">IncludeOptional</a></code></li>
2178 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2181 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2182 <div class="directive-section"><h2><a name="IncludeOptional" id="IncludeOptional">IncludeOptional</a> <a name="includeoptional" id="includeoptional">Directive</a></h2>
2183 <table class="directive">
2184 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2185 the server configuration files</td></tr>
2186 <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>
2187 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2188 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2189 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2190 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in 2.3.6 and later</td></tr>
2192 <p>This directive allows inclusion of other configuration files
2193 from within the server configuration files. It works identically to the
2194 <code class="directive"><a href="#include">Include</a></code> directive, with the
2195 exception that if wildcards do not match any file or directory, the
2196 <code class="directive"><a href="#includeoptional">IncludeOptional</a></code> directive will be
2197 silently ignored instead of causing an error.</p>
2201 <li><code class="directive"><a href="#include">Include</a></code></li>
2202 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2205 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2206 <div class="directive-section"><h2><a name="KeepAlive" id="KeepAlive">KeepAlive</a> <a name="keepalive" id="keepalive">Directive</a></h2>
2207 <table class="directive">
2208 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables HTTP persistent connections</td></tr>
2209 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAlive On|Off</code></td></tr>
2210 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAlive On</code></td></tr>
2211 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2212 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2213 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2215 <p>The Keep-Alive extension to HTTP/1.0 and the persistent
2216 connection feature of HTTP/1.1 provide long-lived HTTP sessions
2217 which allow multiple requests to be sent over the same TCP
2218 connection. In some cases this has been shown to result in an
2219 almost 50% speedup in latency times for HTML documents with
2220 many images. To enable Keep-Alive connections, set
2221 <code>KeepAlive On</code>.</p>
2223 <p>For HTTP/1.0 clients, Keep-Alive connections will only be
2224 used if they are specifically requested by a client. In
2225 addition, a Keep-Alive connection with an HTTP/1.0 client can
2226 only be used when the length of the content is known in
2227 advance. This implies that dynamic content such as CGI output,
2228 SSI pages, and server-generated directory listings will
2229 generally not use Keep-Alive connections to HTTP/1.0 clients.
2230 For HTTP/1.1 clients, persistent connections are the default
2231 unless otherwise specified. If the client requests it, chunked
2232 encoding will be used in order to send content of unknown
2233 length over persistent connections.</p>
2235 <p>When a client uses a Keep-Alive connection it will be counted
2236 as a single "request" for the <code class="directive"><a href="../mod/mpm_common.html#maxconnectionsperchild">MaxConnectionsPerChild</a></code> directive, regardless
2237 of how many requests are sent using the connection.</p>
2241 <li><code class="directive"><a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></code></li>
2244 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2245 <div class="directive-section"><h2><a name="KeepAliveTimeout" id="KeepAliveTimeout">KeepAliveTimeout</a> <a name="keepalivetimeout" id="keepalivetimeout">Directive</a></h2>
2246 <table class="directive">
2247 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for subsequent
2248 requests on a persistent connection</td></tr>
2249 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAliveTimeout <var>num</var>[ms]</code></td></tr>
2250 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAliveTimeout 5</code></td></tr>
2251 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2252 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2253 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2255 <p>The number of seconds Apache httpd will wait for a subsequent
2256 request before closing the connection. By adding a postfix of ms the
2257 timeout can be also set in milliseconds. Once a request has been
2258 received, the timeout value specified by the
2259 <code class="directive"><a href="#timeout">Timeout</a></code> directive applies.</p>
2261 <p>Setting <code class="directive">KeepAliveTimeout</code> to a high value
2262 may cause performance problems in heavily loaded servers. The
2263 higher the timeout, the more server processes will be kept
2264 occupied waiting on connections with idle clients.</p>
2266 <p>If <code class="directive">KeepAliveTimeout</code> is <strong>not</strong>
2267 set for a name-based virtual host, the value of the first defined
2268 virtual host best matching the local IP and port will be used.</p>
2271 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2272 <div class="directive-section"><h2><a name="Limit" id="Limit"><Limit></a> <a name="limit" id="limit">Directive</a></h2>
2273 <table class="directive">
2274 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict enclosed access controls to only certain HTTP
2276 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Limit <var>method</var> [<var>method</var>] ... > ...
2277 </Limit></code></td></tr>
2278 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2279 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2280 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2281 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2283 <p>Access controls are normally effective for
2284 <strong>all</strong> access methods, and this is the usual
2285 desired behavior. <strong>In the general case, access control
2286 directives should not be placed within a
2287 <code class="directive"><Limit></code> section.</strong></p>
2289 <p>The purpose of the <code class="directive"><Limit></code>
2290 directive is to restrict the effect of the access controls to the
2291 nominated HTTP methods. For all other methods, the access
2292 restrictions that are enclosed in the <code class="directive"><Limit></code> bracket <strong>will have no
2293 effect</strong>. The following example applies the access control
2294 only to the methods <code>POST</code>, <code>PUT</code>, and
2295 <code>DELETE</code>, leaving all other methods unprotected:</p>
2297 <pre class="prettyprint lang-config"><Limit POST PUT DELETE>
2299 </Limit></pre>
2302 <p>The method names listed can be one or more of: <code>GET</code>,
2303 <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
2304 <code>CONNECT</code>, <code>OPTIONS</code>,
2305 <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
2306 <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
2307 <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
2308 case-sensitive.</strong> If <code>GET</code> is used it will also
2309 restrict <code>HEAD</code> requests. The <code>TRACE</code> method
2310 cannot be limited (see <code class="directive"><a href="#traceenable">TraceEnable</a></code>).</p>
2312 <div class="warning">A <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section should always be
2313 used in preference to a <code class="directive"><Limit></code>
2314 section when restricting access, since a <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section provides protection
2315 against arbitrary methods.</div>
2317 <p>The <code class="directive"><Limit></code> and
2318 <code class="directive"><a href="#limitexcept"><LimitExcept></a></code>
2319 directives may be nested. In this case, each successive level of
2320 <code class="directive"><Limit></code> or <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> directives must
2321 further restrict the set of methods to which access controls apply.</p>
2323 <div class="warning">When using
2324 <code class="directive"><Limit></code> or
2325 <code class="directive"><LimitExcept></code> directives with
2326 the <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directive,
2327 note that the first <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code>
2328 to succeed authorizes the request, regardless of the presence of other
2329 <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directives.</div>
2331 <p>For example, given the following configuration, all users will
2332 be authorized for <code>POST</code> requests, and the
2333 <code>Require group editors</code> directive will be ignored
2336 <pre class="prettyprint lang-config"><LimitExcept GET>
2338 </LimitExcept>
2340 Require group editors
2341 </Limit></pre>
2345 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2346 <div class="directive-section"><h2><a name="LimitExcept" id="LimitExcept"><LimitExcept></a> <a name="limitexcept" id="limitexcept">Directive</a></h2>
2347 <table class="directive">
2348 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict access controls to all HTTP methods
2349 except the named ones</td></tr>
2350 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LimitExcept <var>method</var> [<var>method</var>] ... > ...
2351 </LimitExcept></code></td></tr>
2352 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2353 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2354 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2355 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2357 <p><code class="directive"><LimitExcept></code> and
2358 <code></LimitExcept></code> are used to enclose
2359 a group of access control directives which will then apply to any
2360 HTTP access method <strong>not</strong> listed in the arguments;
2361 i.e., it is the opposite of a <code class="directive"><a href="#limit"><Limit></a></code> section and can be used to control
2362 both standard and nonstandard/unrecognized methods. See the
2363 documentation for <code class="directive"><a href="#limit"><Limit></a></code> for more details.</p>
2367 <pre class="prettyprint lang-config"><LimitExcept POST GET>
2369 </LimitExcept></pre>
2374 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2375 <div class="directive-section"><h2><a name="LimitInternalRecursion" id="LimitInternalRecursion">LimitInternalRecursion</a> <a name="limitinternalrecursion" id="limitinternalrecursion">Directive</a></h2>
2376 <table class="directive">
2377 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine maximum number of internal redirects and nested
2378 subrequests</td></tr>
2379 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitInternalRecursion <var>number</var> [<var>number</var>]</code></td></tr>
2380 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitInternalRecursion 10</code></td></tr>
2381 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2382 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2383 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2385 <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
2386 redirects the original request to a CGI script. A subrequest is Apache httpd's
2387 mechanism to find out what would happen for some URI if it were requested.
2388 For example, <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> uses subrequests to look for the
2389 files listed in the <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
2392 <p><code class="directive">LimitInternalRecursion</code> prevents the server
2393 from crashing when entering an infinite loop of internal redirects or
2394 subrequests. Such loops are usually caused by misconfigurations.</p>
2396 <p>The directive stores two different limits, which are evaluated on
2397 per-request basis. The first <var>number</var> is the maximum number of
2398 internal redirects, that may follow each other. The second <var>number</var>
2399 determines, how deep subrequests may be nested. If you specify only one
2400 <var>number</var>, it will be assigned to both limits.</p>
2402 <pre class="prettyprint lang-config">LimitInternalRecursion 5</pre>
2406 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2407 <div class="directive-section"><h2><a name="LimitRequestBody" id="LimitRequestBody">LimitRequestBody</a> <a name="limitrequestbody" id="limitrequestbody">Directive</a></h2>
2408 <table class="directive">
2409 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restricts the total size of the HTTP request body sent
2410 from the client</td></tr>
2411 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestBody <var>bytes</var></code></td></tr>
2412 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestBody 0</code></td></tr>
2413 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2414 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2415 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2416 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2418 <p>This directive specifies the number of <var>bytes</var> from 0
2419 (meaning unlimited) to 2147483647 (2GB) that are allowed in a
2420 request body. See the note below for the limited applicability
2421 to proxy requests.</p>
2423 <p>The <code class="directive">LimitRequestBody</code> directive allows
2424 the user to set a limit on the allowed size of an HTTP request
2425 message body within the context in which the directive is given
2426 (server, per-directory, per-file or per-location). If the client
2427 request exceeds that limit, the server will return an error
2428 response instead of servicing the request. The size of a normal
2429 request message body will vary greatly depending on the nature of
2430 the resource and the methods allowed on that resource. CGI scripts
2431 typically use the message body for retrieving form information.
2432 Implementations of the <code>PUT</code> method will require
2433 a value at least as large as any representation that the server
2434 wishes to accept for that resource.</p>
2436 <p>This directive gives the server administrator greater
2437 control over abnormal client request behavior, which may be
2438 useful for avoiding some forms of denial-of-service
2441 <p>If, for example, you are permitting file upload to a particular
2442 location, and wish to limit the size of the uploaded file to 100K,
2443 you might use the following directive:</p>
2445 <pre class="prettyprint lang-config">LimitRequestBody 102400</pre>
2448 <div class="note"><p>For a full description of how this directive is interpreted by
2449 proxy requests, see the <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> documentation.</p>
2454 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2455 <div class="directive-section"><h2><a name="LimitRequestFields" id="LimitRequestFields">LimitRequestFields</a> <a name="limitrequestfields" id="limitrequestfields">Directive</a></h2>
2456 <table class="directive">
2457 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of HTTP request header fields that
2458 will be accepted from the client</td></tr>
2459 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFields <var>number</var></code></td></tr>
2460 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFields 100</code></td></tr>
2461 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2462 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2463 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2465 <p><var>Number</var> is an integer from 0 (meaning unlimited) to
2466 32767. The default value is defined by the compile-time
2467 constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
2470 <p>The <code class="directive">LimitRequestFields</code> directive allows
2471 the server administrator to modify the limit on the number of
2472 request header fields allowed in an HTTP request. A server needs
2473 this value to be larger than the number of fields that a normal
2474 client request might include. The number of request header fields
2475 used by a client rarely exceeds 20, but this may vary among
2476 different client implementations, often depending upon the extent
2477 to which a user has configured their browser to support detailed
2478 content negotiation. Optional HTTP extensions are often expressed
2479 using request header fields.</p>
2481 <p>This directive gives the server administrator greater
2482 control over abnormal client request behavior, which may be
2483 useful for avoiding some forms of denial-of-service attacks.
2484 The value should be increased if normal clients see an error
2485 response from the server that indicates too many fields were
2486 sent in the request.</p>
2490 <pre class="prettyprint lang-config">LimitRequestFields 50</pre>
2493 <div class="warning"><h3>Warning</h3>
2494 <p> When name-based virtual hosting is used, the value for this
2495 directive is taken from the default (first-listed) virtual host for the
2496 local IP and port combination.</p>
2501 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2502 <div class="directive-section"><h2><a name="LimitRequestFieldSize" id="LimitRequestFieldSize">LimitRequestFieldSize</a> <a name="limitrequestfieldsize" id="limitrequestfieldsize">Directive</a></h2>
2503 <table class="directive">
2504 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of the HTTP request header allowed from the
2506 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFieldSize <var>bytes</var></code></td></tr>
2507 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFieldSize 8190</code></td></tr>
2508 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2509 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2510 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2512 <p>This directive specifies the number of <var>bytes</var>
2513 that will be allowed in an HTTP request header.</p>
2515 <p>The <code class="directive">LimitRequestFieldSize</code> directive
2516 allows the server administrator to set the limit
2517 on the allowed size of an HTTP request header field. A server
2518 needs this value to be large enough to hold any one header field
2519 from a normal client request. The size of a normal request header
2520 field will vary greatly among different client implementations,
2521 often depending upon the extent to which a user has configured
2522 their browser to support detailed content negotiation. SPNEGO
2523 authentication headers can be up to 12392 bytes.</p>
2525 <p>This directive gives the server administrator greater
2526 control over abnormal client request behavior, which may be
2527 useful for avoiding some forms of denial-of-service attacks.</p>
2531 <pre class="prettyprint lang-config">LimitRequestFieldSize 4094</pre>
2534 <div class="note">Under normal conditions, the value should not be changed from
2537 <div class="warning"><h3>Warning</h3>
2538 <p> When name-based virtual hosting is used, the value for this
2539 directive is taken from the default (first-listed) virtual host best
2540 matching the current IP address and port combination.</p>
2544 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2545 <div class="directive-section"><h2><a name="LimitRequestLine" id="LimitRequestLine">LimitRequestLine</a> <a name="limitrequestline" id="limitrequestline">Directive</a></h2>
2546 <table class="directive">
2547 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limit the size of the HTTP request line that will be accepted
2548 from the client</td></tr>
2549 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestLine <var>bytes</var></code></td></tr>
2550 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestLine 8190</code></td></tr>
2551 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2552 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2553 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2555 <p>This directive sets the number of <var>bytes</var> that will be
2556 allowed on the HTTP request-line.</p>
2558 <p>The <code class="directive">LimitRequestLine</code> directive allows
2559 the server administrator to set the limit on the allowed size
2560 of a client's HTTP request-line. Since the request-line consists of the
2561 HTTP method, URI, and protocol version, the
2562 <code class="directive">LimitRequestLine</code> directive places a
2563 restriction on the length of a request-URI allowed for a request
2564 on the server. A server needs this value to be large enough to
2565 hold any of its resource names, including any information that
2566 might be passed in the query part of a <code>GET</code> request.</p>
2568 <p>This directive gives the server administrator greater
2569 control over abnormal client request behavior, which may be
2570 useful for avoiding some forms of denial-of-service attacks.</p>
2574 <pre class="prettyprint lang-config">LimitRequestLine 4094</pre>
2577 <div class="note">Under normal conditions, the value should not be changed from
2580 <div class="warning"><h3>Warning</h3>
2581 <p> When name-based virtual hosting is used, the value for this
2582 directive is taken from the default (first-listed) virtual host best
2583 matching the current IP address and port combination.</p>
2588 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2589 <div class="directive-section"><h2><a name="LimitXMLRequestBody" id="LimitXMLRequestBody">LimitXMLRequestBody</a> <a name="limitxmlrequestbody" id="limitxmlrequestbody">Directive</a></h2>
2590 <table class="directive">
2591 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of an XML-based request body</td></tr>
2592 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitXMLRequestBody <var>bytes</var></code></td></tr>
2593 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitXMLRequestBody 1000000</code></td></tr>
2594 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2595 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2596 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2597 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2599 <p>Limit (in bytes) on maximum size of an XML-based request
2600 body. A value of <code>0</code> will disable any checking.</p>
2604 <pre class="prettyprint lang-config">LimitXMLRequestBody 0</pre>
2609 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2610 <div class="directive-section"><h2><a name="Location" id="Location"><Location></a> <a name="location" id="location">Directive</a></h2>
2611 <table class="directive">
2612 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to matching
2614 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Location
2615 <var>URL-path</var>|<var>URL</var>> ... </Location></code></td></tr>
2616 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2617 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2618 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2620 <p>The <code class="directive"><Location></code> directive
2621 limits the scope of the enclosed directives by URL. It is similar to the
2622 <code class="directive"><a href="#directory"><Directory></a></code>
2623 directive, and starts a subsection which is terminated with a
2624 <code></Location></code> directive. <code class="directive"><Location></code> sections are processed in the
2625 order they appear in the configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
2626 <code>.htaccess</code> files are read, and after the <code class="directive"><a href="#files"><Files></a></code> sections.</p>
2628 <p><code class="directive"><Location></code> sections operate
2629 completely outside the filesystem. This has several consequences.
2630 Most importantly, <code class="directive"><Location></code>
2631 directives should not be used to control access to filesystem
2632 locations. Since several different URLs may map to the same
2633 filesystem location, such access controls may by circumvented.</p>
2635 <p>The enclosed directives will be applied to the request if the path component
2636 of the URL meets <em>any</em> of the following criteria:
2639 <li>The specified location matches exactly the path component of the URL.
2641 <li>The specified location, which ends in a forward slash, is a prefix
2642 of the path component of the URL (treated as a context root).
2644 <li>The specified location, with the addition of a trailing slash, is a
2645 prefix of the path component of the URL (also treated as a context root).
2649 In the example below, where no trailing slash is used, requests to
2650 /private1, /private1/ and /private1/file.txt will have the enclosed
2651 directives applied, but /private1other would not.
2653 <pre class="prettyprint lang-config"><Location /private1>
2655 </Location></pre>
2658 In the example below, where a trailing slash is used, requests to
2659 /private2/ and /private2/file.txt will have the enclosed
2660 directives applied, but /private2 and /private2other would not.
2662 <pre class="prettyprint lang-config"><Location /private2<em>/</em>>
2664 </Location></pre>
2667 <div class="note"><h3>When to use <code class="directive"><Location></code></h3>
2669 <p>Use <code class="directive"><Location></code> to apply
2670 directives to content that lives outside the filesystem. For
2671 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
2672 <code><Location /></code>, which is an easy way to
2673 apply a configuration to the entire server.</p>
2676 <p>For all origin (non-proxy) requests, the URL to be matched is a
2677 URL-path of the form <code>/path/</code>. <em>No scheme, hostname,
2678 port, or query string may be included.</em> For proxy requests, the
2679 URL to be matched is of the form
2680 <code>scheme://servername/path</code>, and you must include the
2683 <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
2684 any single character, and <code>*</code> matches any sequences of
2685 characters. Neither wildcard character matches a / in the URL-path.</p>
2687 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
2688 can also be used, with the addition of the <code>~</code>
2689 character. For example:</p>
2691 <pre class="prettyprint lang-config"><Location ~ "/(extra|special)/data">
2693 </Location></pre>
2696 <p>would match URLs that contained the substring <code>/extra/data</code>
2697 or <code>/special/data</code>. The directive <code class="directive"><a href="#locationmatch"><LocationMatch></a></code> behaves
2698 identical to the regex version of <code class="directive"><Location></code>, and is preferred, for the
2699 simple reason that <code>~</code> is hard to distinguish from
2700 <code>-</code> in many fonts.</p>
2702 <p>The <code class="directive"><Location></code>
2703 functionality is especially useful when combined with the
2704 <code class="directive"><a href="#sethandler">SetHandler</a></code>
2705 directive. For example, to enable status requests, but allow them
2706 only from browsers at <code>example.com</code>, you might use:</p>
2708 <pre class="prettyprint lang-config"><Location /status>
2709 SetHandler server-status
2710 Require host example.com
2711 </Location></pre>
2714 <div class="note"><h3>Note about / (slash)</h3>
2715 <p>The slash character has special meaning depending on where in a
2716 URL it appears. People may be used to its behavior in the filesystem
2717 where multiple adjacent slashes are frequently collapsed to a single
2718 slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
2719 <code>/home/foo</code>). In URL-space this is not necessarily true.
2720 The <code class="directive"><a href="#locationmatch"><LocationMatch></a></code>
2721 directive and the regex version of <code class="directive"><Location></code> require you to explicitly specify multiple
2722 slashes if that is your intention.</p>
2724 <p>For example, <code><LocationMatch ^/abc></code> would match
2725 the request URL <code>/abc</code> but not the request URL <code>
2726 //abc</code>. The (non-regex) <code class="directive"><Location></code> directive behaves similarly when used for
2727 proxy requests. But when (non-regex) <code class="directive"><Location></code> is used for non-proxy requests it will
2728 implicitly match multiple slashes with a single slash. For example,
2729 if you specify <code><Location /abc/def></code> and the
2730 request is to <code>/abc//def</code> then it will match.</p>
2735 <li><a href="../sections.html">How <Directory>, <Location>
2736 and <Files> sections work</a> for an explanation of how these
2737 different sections are combined when a request is received.</li>
2738 <li><code class="directive"><a href="#locationmatch">LocationMatch</a></code></li>
2741 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2742 <div class="directive-section"><h2><a name="LocationMatch" id="LocationMatch"><LocationMatch></a> <a name="locationmatch" id="locationmatch">Directive</a></h2>
2743 <table class="directive">
2744 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to regular-expression
2745 matching URLs</td></tr>
2746 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LocationMatch
2747 <var>regex</var>> ... </LocationMatch></code></td></tr>
2748 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2749 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2750 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2752 <p>The <code class="directive"><LocationMatch></code> directive
2753 limits the scope of the enclosed directives by URL, in an identical manner
2754 to <code class="directive"><a href="#location"><Location></a></code>. However,
2755 it takes a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
2756 as an argument instead of a simple string. For example:</p>
2758 <pre class="prettyprint lang-config"><LocationMatch "/(extra|special)/data">
2760 </LocationMatch></pre>
2763 <p>would match URLs that contained the substring <code>/extra/data</code>
2764 or <code>/special/data</code>.</p>
2766 <div class="note"><p>If the intent is that a URL <strong>starts with</strong>
2767 <code>/extra/data</code>, rather than merely
2768 <strong>contains</strong> <code>/extra/data</code>, prefix the
2769 regular expression with a <code>^</code> to require this.</p>
2771 <pre class="prettyprint lang-config"><LocationMatch "^/(extra|special)/data"></pre>
2775 <p>From 2.4.8 onwards, named groups and backreferences are captured and
2776 written to the environment with the corresponding name prefixed with
2777 "MATCH_" and in upper case. This allows elements of URLs to be referenced
2778 from within <a href="../expr.html">expressions</a> and modules like
2779 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
2780 (unnamed) backreferences are ignored. Use named groups instead.</p>
2782 <pre class="prettyprint lang-config"><LocationMatch ^/combined/(?<sitename>[^/]+)>
2783 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
2784 </LocationMatch></pre>
2789 <li><a href="../sections.html">How <Directory>, <Location>
2790 and <Files> sections work</a> for an explanation of how these
2791 different sections are combined when a request is received</li>
2794 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2795 <div class="directive-section"><h2><a name="LogLevel" id="LogLevel">LogLevel</a> <a name="loglevel" id="loglevel">Directive</a></h2>
2796 <table class="directive">
2797 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Controls the verbosity of the ErrorLog</td></tr>
2798 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel [<var>module</var>:]<var>level</var>
2799 [<var>module</var>:<var>level</var>] ...
2801 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LogLevel warn</code></td></tr>
2802 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2803 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2804 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2805 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Per-module and per-directory configuration is available in
2806 Apache HTTP Server 2.3.6 and later</td></tr>
2808 <p><code class="directive">LogLevel</code> adjusts the verbosity of the
2809 messages recorded in the error logs (see <code class="directive"><a href="#errorlog">ErrorLog</a></code> directive). The following
2810 <var>level</var>s are available, in order of decreasing
2813 <table class="bordered">
2816 <th><strong>Level</strong> </th>
2818 <th><strong>Description</strong> </th>
2820 <th><strong>Example</strong> </th>
2824 <td><code>emerg</code> </td>
2826 <td>Emergencies - system is unusable.</td>
2828 <td>"Child cannot open lock file. Exiting"</td>
2832 <td><code>alert</code> </td>
2834 <td>Action must be taken immediately.</td>
2836 <td>"getpwuid: couldn't determine user name from uid"</td>
2840 <td><code>crit</code> </td>
2842 <td>Critical Conditions.</td>
2844 <td>"socket: Failed to get a socket, exiting child"</td>
2848 <td><code>error</code> </td>
2850 <td>Error conditions.</td>
2852 <td>"Premature end of script headers"</td>
2856 <td><code>warn</code> </td>
2858 <td>Warning conditions.</td>
2860 <td>"child process 1234 did not exit, sending another
2865 <td><code>notice</code> </td>
2867 <td>Normal but significant condition.</td>
2869 <td>"httpd: caught SIGBUS, attempting to dump core in
2874 <td><code>info</code> </td>
2876 <td>Informational.</td>
2878 <td>"Server seems busy, (you may need to increase
2879 StartServers, or Min/MaxSpareServers)..."</td>
2883 <td><code>debug</code> </td>
2885 <td>Debug-level messages</td>
2887 <td>"Opening config file ..."</td>
2890 <td><code>trace1</code> </td>
2892 <td>Trace messages</td>
2894 <td>"proxy: FTP: control connection complete"</td>
2897 <td><code>trace2</code> </td>
2899 <td>Trace messages</td>
2901 <td>"proxy: CONNECT: sending the CONNECT request to the remote proxy"</td>
2904 <td><code>trace3</code> </td>
2906 <td>Trace messages</td>
2908 <td>"openssl: Handshake: start"</td>
2911 <td><code>trace4</code> </td>
2913 <td>Trace messages</td>
2915 <td>"read from buffered SSL brigade, mode 0, 17 bytes"</td>
2918 <td><code>trace5</code> </td>
2920 <td>Trace messages</td>
2922 <td>"map lookup FAILED: map=rewritemap key=keyname"</td>
2925 <td><code>trace6</code> </td>
2927 <td>Trace messages</td>
2929 <td>"cache lookup FAILED, forcing new map lookup"</td>
2932 <td><code>trace7</code> </td>
2934 <td>Trace messages, dumping large amounts of data</td>
2936 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2939 <td><code>trace8</code> </td>
2941 <td>Trace messages, dumping large amounts of data</td>
2943 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2947 <p>When a particular level is specified, messages from all
2948 other levels of higher significance will be reported as well.
2949 <em>E.g.</em>, when <code>LogLevel info</code> is specified,
2950 then messages with log levels of <code>notice</code> and
2951 <code>warn</code> will also be posted.</p>
2953 <p>Using a level of at least <code>crit</code> is
2958 <pre class="prettyprint lang-config">LogLevel notice</pre>
2961 <div class="note"><h3>Note</h3>
2962 <p>When logging to a regular file messages of the level
2963 <code>notice</code> cannot be suppressed and thus are always
2964 logged. However, this doesn't apply when logging is done
2965 using <code>syslog</code>.</p>
2968 <p>Specifying a level without a module name will reset the level
2969 for all modules to that level. Specifying a level with a module
2970 name will set the level for that module only. It is possible to
2971 use the module source file name, the module identifier, or the
2972 module identifier with the trailing <code>_module</code> omitted
2973 as module specification. This means the following three specifications
2976 <pre class="prettyprint lang-config">LogLevel info ssl:warn
2977 LogLevel info mod_ssl.c:warn
2978 LogLevel info ssl_module:warn</pre>
2981 <p>It is also possible to change the level per directory:</p>
2983 <pre class="prettyprint lang-config">LogLevel info
2984 <Directory "/usr/local/apache/htdocs/app">
2986 </Directory></pre>
2990 Per directory loglevel configuration only affects messages that are
2991 logged after the request has been parsed and that are associated with
2992 the request. Log messages which are associated with the server or
2993 the connection are not affected. The latter can be influenced by the
2994 <code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code> directive,
3000 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
3001 <li><code class="directive"><a href="#errorlogformat">ErrorLogFormat</a></code></li>
3002 <li><code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code></li>
3003 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
3006 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3007 <div class="directive-section"><h2><a name="LogLevelOverride" id="LogLevelOverride">LogLevelOverride</a> <a name="logleveloverride" id="logleveloverride">Directive</a></h2>
3008 <table class="directive">
3009 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Override the verbosity of the ErrorLog for certain clients</td></tr>
3010 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel <var>ipaddress</var>[/<var>prefixlen</var>]
3011 [<var>module</var>:]<var>level</var> [<var>module</var>:<var>level</var>] ...
3013 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>unset</code></td></tr>
3014 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3015 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3016 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3017 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.5.0 and later</td></tr>
3019 <p><code class="directive">LogLevelOverride</code> adjusts the
3020 <code class="directive"><a href="#loglevel">LogLevel</a></code> for requests coming from
3021 certain client IP addresses.
3022 This allows to enable verbose logging only for certain test clients.
3023 The IP address is checked at a very early state in the connection
3024 processing. Therefore, <code class="directive">LogLevelOverride</code> allows to
3025 change the log level for things like the SSL handshake which happen before
3026 a <code class="directive"><a href="#loglevel">LogLevel</a></code> directive in an
3027 <code class="directive"><a href="#if"><If></a></code> container would
3030 <p><code class="directive">LogLevelOverride</code> accepts either a single
3031 IP-address or a CIDR IP-address/len subnet specification.
3032 For the syntax of the loglevel specification, see the
3033 <code class="directive"><a href="#loglevel">LogLevel</a></code> directive.</p>
3035 <p>For requests that match a <code class="directive">LogLevelOverride</code>
3036 directive, per-directory specifications of
3037 <code class="directive"><a href="#loglevel">LogLevel</a></code> are ignored.</p>
3041 <pre class="prettyprint lang-config"> LogLevelOverride 192.0.2.0/24 ssl:trace6
3042 LogLevelOverride 192.0.2.7 ssl:trace8</pre>
3046 <code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code> only affects
3047 log messages that are associated with the request or the connection.
3048 Log messages which are associated with the server not affected.
3054 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
3057 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3058 <div class="directive-section"><h2><a name="MaxKeepAliveRequests" id="MaxKeepAliveRequests">MaxKeepAliveRequests</a> <a name="maxkeepaliverequests" id="maxkeepaliverequests">Directive</a></h2>
3059 <table class="directive">
3060 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of requests allowed on a persistent
3061 connection</td></tr>
3062 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxKeepAliveRequests <var>number</var></code></td></tr>
3063 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxKeepAliveRequests 100</code></td></tr>
3064 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3065 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3066 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3068 <p>The <code class="directive">MaxKeepAliveRequests</code> directive
3069 limits the number of requests allowed per connection when
3070 <code class="directive"><a href="#keepalive">KeepAlive</a></code> is on. If it is
3071 set to <code>0</code>, unlimited requests will be allowed. We
3072 recommend that this setting be kept to a high value for maximum
3073 server performance.</p>
3077 <pre class="prettyprint lang-config">MaxKeepAliveRequests 500</pre>
3081 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3082 <div class="directive-section"><h2><a name="MaxRangeOverlaps" id="MaxRangeOverlaps">MaxRangeOverlaps</a> <a name="maxrangeoverlaps" id="maxrangeoverlaps">Directive</a></h2>
3083 <table class="directive">
3084 <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
3086 <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>
3087 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeOverlaps 20</code></td></tr>
3088 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3089 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3090 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3091 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3093 <p>The <code class="directive">MaxRangeOverlaps</code> directive
3094 limits the number of overlapping HTTP ranges the server is willing to
3095 return to the client. If more overlapping ranges than permitted are requested,
3096 the complete resource is returned instead.</p>
3099 <dt><strong>default</strong></dt>
3100 <dd>Limits the number of overlapping ranges to a compile-time default of 20.</dd>
3102 <dt><strong>none</strong></dt>
3103 <dd>No overlapping Range headers are allowed.</dd>
3105 <dt><strong>unlimited</strong></dt>
3106 <dd>The server does not limit the number of overlapping ranges it is
3107 willing to satisfy.</dd>
3109 <dt><var>number-of-ranges</var></dt>
3110 <dd>A positive number representing the maximum number of overlapping ranges the
3111 server is willing to satisfy.</dd>
3115 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3116 <div class="directive-section"><h2><a name="MaxRangeReversals" id="MaxRangeReversals">MaxRangeReversals</a> <a name="maxrangereversals" id="maxrangereversals">Directive</a></h2>
3117 <table class="directive">
3118 <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
3120 <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>
3121 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeReversals 20</code></td></tr>
3122 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3123 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3124 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3125 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3127 <p>The <code class="directive">MaxRangeReversals</code> directive
3128 limits the number of HTTP Range reversals the server is willing to
3129 return to the client. If more ranges reversals than permitted are requested,
3130 the complete resource is returned instead.</p>
3133 <dt><strong>default</strong></dt>
3134 <dd>Limits the number of range reversals to a compile-time default of 20.</dd>
3136 <dt><strong>none</strong></dt>
3137 <dd>No Range reversals headers are allowed.</dd>
3139 <dt><strong>unlimited</strong></dt>
3140 <dd>The server does not limit the number of range reversals it is
3141 willing to satisfy.</dd>
3143 <dt><var>number-of-ranges</var></dt>
3144 <dd>A positive number representing the maximum number of range reversals the
3145 server is willing to satisfy.</dd>
3149 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3150 <div class="directive-section"><h2><a name="MaxRanges" id="MaxRanges">MaxRanges</a> <a name="maxranges" id="maxranges">Directive</a></h2>
3151 <table class="directive">
3152 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of ranges allowed before returning the complete
3154 <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>
3155 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRanges 200</code></td></tr>
3156 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3157 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3158 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3159 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3161 <p>The <code class="directive">MaxRanges</code> directive
3162 limits the number of HTTP ranges the server is willing to
3163 return to the client. If more ranges than permitted are requested,
3164 the complete resource is returned instead.</p>
3167 <dt><strong>default</strong></dt>
3168 <dd>Limits the number of ranges to a compile-time default of 200.</dd>
3170 <dt><strong>none</strong></dt>
3171 <dd>Range headers are ignored.</dd>
3173 <dt><strong>unlimited</strong></dt>
3174 <dd>The server does not limit the number of ranges it is
3175 willing to satisfy.</dd>
3177 <dt><var>number-of-ranges</var></dt>
3178 <dd>A positive number representing the maximum number of ranges the
3179 server is willing to satisfy.</dd>
3183 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3184 <div class="directive-section"><h2><a name="MergeTrailers" id="MergeTrailers">MergeTrailers</a> <a name="mergetrailers" id="mergetrailers">Directive</a></h2>
3185 <table class="directive">
3186 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determins whether trailers are merged into headers</td></tr>
3187 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MergeTrailers [on|off]</code></td></tr>
3188 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MergeTrailers off</code></td></tr>
3189 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3190 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3191 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3192 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.4.10 and later</td></tr>
3194 <p>This directive controls whether HTTP trailers are copied into the
3195 internal representation of HTTP headers. This mergeing occurs when the
3196 request body has been completely consumed, long after most header
3197 processing would have a chance to examine or modify request headers.</p>
3198 <p>This option is provided for compatibility with releases prior to 2.4.10,
3199 where trailers were always merged.</p>
3202 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3203 <div class="directive-section"><h2><a name="Mutex" id="Mutex">Mutex</a> <a name="mutex" id="mutex">Directive</a></h2>
3204 <table class="directive">
3205 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures mutex mechanism and lock file directory for all
3206 or specified mutexes</td></tr>
3207 <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>
3208 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Mutex default</code></td></tr>
3209 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3210 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3211 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3212 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.4 and later</td></tr>
3214 <p>The <code class="directive">Mutex</code> directive sets the mechanism,
3215 and optionally the lock file location, that httpd and modules use
3216 to serialize access to resources. Specify <code>default</code> as
3217 the first argument to change the settings for all mutexes; specify
3218 a mutex name (see table below) as the first argument to override
3219 defaults only for that mutex.</p>
3221 <p>The <code class="directive">Mutex</code> directive is typically used in
3222 the following exceptional situations:</p>
3225 <li>change the mutex mechanism when the default mechanism selected
3226 by <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> has a functional or performance
3229 <li>change the directory used by file-based mutexes when the
3230 default directory does not support locking</li>
3233 <div class="note"><h3>Supported modules</h3>
3234 <p>This directive only configures mutexes which have been registered
3235 with the core server using the <code>ap_mutex_register()</code> API.
3236 All modules bundled with httpd support the <code class="directive">Mutex</code>
3237 directive, but third-party modules may not. Consult the documentation
3238 of the third-party module, which must indicate the mutex name(s) which
3239 can be configured if this directive is supported.</p>
3242 <p>The following mutex <em>mechanisms</em> are available:</p>
3244 <li><code>default | yes</code>
3245 <p>This selects the default locking implementation, as determined by
3246 <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a>. The default locking implementation can
3247 be displayed by running <code class="program"><a href="../programs/httpd.html">httpd</a></code> with the
3248 <code>-V</code> option.</p></li>
3250 <li><code>none | no</code>
3251 <p>This effectively disables the mutex, and is only allowed for a
3252 mutex if the module indicates that it is a valid choice. Consult the
3253 module documentation for more information.</p></li>
3255 <li><code>posixsem</code>
3256 <p>This is a mutex variant based on a Posix semaphore.</p>
3258 <div class="warning"><h3>Warning</h3>
3259 <p>The semaphore ownership is not recovered if a thread in the process
3260 holding the mutex segfaults, resulting in a hang of the web server.</p>
3264 <li><code>sysvsem</code>
3265 <p>This is a mutex variant based on a SystemV IPC semaphore.</p>
3267 <div class="warning"><h3>Warning</h3>
3268 <p>It is possible to "leak" SysV semaphores if processes crash
3269 before the semaphore is removed.</p>
3272 <div class="warning"><h3>Security</h3>
3273 <p>The semaphore API allows for a denial of service attack by any
3274 CGIs running under the same uid as the webserver (<em>i.e.</em>,
3275 all CGIs, unless you use something like <code class="program"><a href="../programs/suexec.html">suexec</a></code>
3276 or <code>cgiwrapper</code>).</p>
3280 <li><code>sem</code>
3281 <p>This selects the "best" available semaphore implementation, choosing
3282 between Posix and SystemV IPC semaphores, in that order.</p></li>
3284 <li><code>pthread</code>
3285 <p>This is a mutex variant based on cross-process Posix thread
3288 <div class="warning"><h3>Warning</h3>
3289 <p>On most systems, if a child process terminates abnormally while
3290 holding a mutex that uses this implementation, the server will deadlock
3291 and stop responding to requests. When this occurs, the server will
3292 require a manual restart to recover.</p>
3293 <p>Solaris is a notable exception as it provides a mechanism which
3294 usually allows the mutex to be recovered after a child process
3295 terminates abnormally while holding a mutex.</p>
3296 <p>If your system implements the
3297 <code>pthread_mutexattr_setrobust_np()</code> function, you may be able
3298 to use the <code>pthread</code> option safely.</p>
3302 <li><code>fcntl:/path/to/mutex</code>
3303 <p>This is a mutex variant where a physical (lock-)file and the
3304 <code>fcntl()</code> function are used as the mutex.</p>
3306 <div class="warning"><h3>Warning</h3>
3307 <p>When multiple mutexes based on this mechanism are used within
3308 multi-threaded, multi-process environments, deadlock errors (EDEADLK)
3309 can be reported for valid mutex operations if <code>fcntl()</code>
3310 is not thread-aware, such as on Solaris.</p>
3314 <li><code>flock:/path/to/mutex</code>
3315 <p>This is similar to the <code>fcntl:/path/to/mutex</code> method
3316 with the exception that the <code>flock()</code> function is used to
3317 provide file locking.</p></li>
3319 <li><code>file:/path/to/mutex</code>
3320 <p>This selects the "best" available file locking implementation,
3321 choosing between <code>fcntl</code> and <code>flock</code>, in that
3325 <p>Most mechanisms are only available on selected platforms, where the
3326 underlying platform and <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> support it. Mechanisms
3327 which aren't available on all platforms are <em>posixsem</em>,
3328 <em>sysvsem</em>, <em>sem</em>, <em>pthread</em>, <em>fcntl</em>,
3329 <em>flock</em>, and <em>file</em>.</p>
3331 <p>With the file-based mechanisms <em>fcntl</em> and <em>flock</em>,
3332 the path, if provided, is a directory where the lock file will be created.
3333 The default directory is httpd's run-time file directory,
3334 <code class="directive"><a href="#defaultruntimedir">DefaultRuntimeDir</a></code>. If a relative
3335 path is provided, it is relative to
3336 <code class="directive"><a href="#defaultruntimedir">DefaultRuntimeDir</a></code>. Always use a local
3337 disk filesystem for <code>/path/to/mutex</code> and never a directory residing
3338 on a NFS- or AFS-filesystem. The basename of the file will be the mutex
3339 type, an optional instance string provided by the module, and unless the
3340 <code>OmitPID</code> keyword is specified, the process id of the httpd
3341 parent process will be appended to to make the file name unique, avoiding
3342 conflicts when multiple httpd instances share a lock file directory. For
3343 example, if the mutex name is <code>mpm-accept</code> and the lock file
3344 directory is <code>/var/httpd/locks</code>, the lock file name for the
3345 httpd instance with parent process id 12345 would be
3346 <code>/var/httpd/locks/mpm-accept.12345</code>.</p>
3348 <div class="warning"><h3>Security</h3>
3349 <p>It is best to <em>avoid</em> putting mutex files in a world-writable
3350 directory such as <code>/var/tmp</code> because someone could create
3351 a denial of service attack and prevent the server from starting by
3352 creating a lockfile with the same name as the one the server will try
3356 <p>The following table documents the names of mutexes used by httpd
3357 and bundled modules.</p>
3359 <table class="bordered"><tr class="header">
3362 <th>Protected resource</th>
3365 <td><code>mpm-accept</code></td>
3366 <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>
3367 <td>incoming connections, to avoid the thundering herd problem;
3368 for more information, refer to the
3369 <a href="../misc/perf-tuning.html">performance tuning</a>
3373 <td><code>authdigest-client</code></td>
3374 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3375 <td>client list in shared memory</td>
3378 <td><code>authdigest-opaque</code></td>
3379 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3380 <td>counter in shared memory</td>
3383 <td><code>ldap-cache</code></td>
3384 <td><code class="module"><a href="../mod/mod_ldap.html">mod_ldap</a></code></td>
3385 <td>LDAP result cache</td>
3388 <td><code>rewrite-map</code></td>
3389 <td><code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code></td>
3390 <td>communication with external mapping programs, to avoid
3391 intermixed I/O from multiple requests</td>
3394 <td><code>ssl-cache</code></td>
3395 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3396 <td>SSL session cache</td>
3399 <td><code>ssl-stapling</code></td>
3400 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3401 <td>OCSP stapling response cache</td>
3404 <td><code>watchdog-callback</code></td>
3405 <td><code class="module"><a href="../mod/mod_watchdog.html">mod_watchdog</a></code></td>
3406 <td>callback function of a particular client module</td>
3410 <p>The <code>OmitPID</code> keyword suppresses the addition of the httpd
3411 parent process id from the lock file name.</p>
3413 <p>In the following example, the mutex mechanism for the MPM accept
3414 mutex will be changed from the compiled-in default to <code>fcntl</code>,
3415 with the associated lock file created in directory
3416 <code>/var/httpd/locks</code>. The mutex mechanism for all other mutexes
3417 will be changed from the compiled-in default to <code>sysvsem</code>.</p>
3419 <pre class="prettyprint lang-config">Mutex sysvsem default
3420 Mutex fcntl:/var/httpd/locks mpm-accept</pre>
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="NameVirtualHost" id="NameVirtualHost">NameVirtualHost</a> <a name="namevirtualhost" id="namevirtualhost">Directive</a></h2>
3426 <table class="directive">
3427 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>DEPRECATED: Designates an IP address for name-virtual
3429 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NameVirtualHost <var>addr</var>[:<var>port</var>]</code></td></tr>
3430 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3431 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3432 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3435 <p>Prior to 2.3.11, <code class="directive">NameVirtualHost</code> was required
3436 to instruct the server that a particular IP address and port combination
3437 was usable as a name-based virtual host. In 2.3.11 and later,
3438 any time an IP address and port combination is used in multiple virtual
3439 hosts, name-based virtual hosting is automatically enabled for that address.</p>
3441 <p>This directive currently has no effect.</p>
3445 <li><a href="../vhosts/">Virtual Hosts
3446 documentation</a></li>
3449 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3450 <div class="directive-section"><h2><a name="Options" id="Options">Options</a> <a name="options" id="options">Directive</a></h2>
3451 <table class="directive">
3452 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures what features are available in a particular
3454 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Options
3455 [+|-]<var>option</var> [[+|-]<var>option</var>] ...</code></td></tr>
3456 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Options FollowSymlinks</code></td></tr>
3457 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3458 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
3459 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3460 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3461 <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>
3463 <p>The <code class="directive">Options</code> directive controls which
3464 server features are available in a particular directory.</p>
3466 <p><var>option</var> can be set to <code>None</code>, in which
3467 case none of the extra features are enabled, or one or more of
3471 <dt><code>All</code></dt>
3473 <dd>All options except for <code>MultiViews</code>.</dd>
3475 <dt><code>ExecCGI</code></dt>
3478 Execution of CGI scripts using <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>
3481 <dt><code>FollowSymLinks</code></dt>
3484 The server will follow symbolic links in this directory. This is
3485 the default setting.
3487 <p>Even though the server follows the symlink it does <em>not</em>
3488 change the pathname used to match against <code class="directive"><a href="#directory"><Directory></a></code> sections.</p>
3490 <p>The <code>FollowSymLinks</code> and
3491 <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
3492 <code>.htaccess</code> files.</p>
3494 <p>Omitting this option should not be considered a security restriction,
3495 since symlink testing is subject to race conditions that make it
3499 <dt><code>Includes</code></dt>
3502 Server-side includes provided by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
3505 <dt><code>IncludesNOEXEC</code></dt>
3509 Server-side includes are permitted, but the <code>#exec
3510 cmd</code> and <code>#exec cgi</code> are disabled. It is still
3511 possible to <code>#include virtual</code> CGI scripts from
3512 <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>ed
3515 <dt><code>Indexes</code></dt>
3518 If a URL which maps to a directory is requested, and there
3519 is no <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
3520 (<em>e.g.</em>, <code>index.html</code>) in that directory, then
3521 <code class="module"><a href="../mod/mod_autoindex.html">mod_autoindex</a></code> will return a formatted listing
3522 of the directory.</dd>
3524 <dt><code>MultiViews</code></dt>
3527 <a href="../content-negotiation.html">Content negotiated</a>
3528 "MultiViews" are allowed using
3529 <code class="module"><a href="../mod/mod_negotiation.html">mod_negotiation</a></code>.
3530 <div class="note"><h3>Note</h3> <p>This option gets ignored if set
3531 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>
3532 needs real resources to compare against and evaluate from.</p></div>
3535 <dt><code>SymLinksIfOwnerMatch</code></dt>
3537 <dd>The server will only follow symbolic links for which the
3538 target file or directory is owned by the same user id as the
3541 <div class="note"><h3>Note</h3>
3542 <p>The <code>FollowSymLinks</code> and
3543 <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
3544 <code>.htaccess</code> files.</p>
3546 <p>This option should not be considered a security restriction,
3547 since symlink testing is subject to race conditions that make it
3552 <p>Normally, if multiple <code class="directive">Options</code> could
3553 apply to a directory, then the most specific one is used and
3554 others are ignored; the options are not merged. (See <a href="../sections.html#mergin">how sections are merged</a>.)
3555 However if <em>all</em> the options on the
3556 <code class="directive">Options</code> directive are preceded by a
3557 <code>+</code> or <code>-</code> symbol, the options are
3558 merged. Any options preceded by a <code>+</code> are added to the
3559 options currently in force, and any options preceded by a
3560 <code>-</code> are removed from the options currently in
3563 <div class="note"><h3>Note</h3>
3564 <p>Mixing <code class="directive">Options</code> with a <code>+</code> or
3565 <code>-</code> with those without is not valid syntax, and will be
3566 rejected during server startup by the syntax check with an abort.</p>
3569 <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>
3571 <pre class="prettyprint lang-config"><Directory "/web/docs">
3572 Options Indexes FollowSymLinks
3575 <Directory "/web/docs/spec">
3577 </Directory></pre>
3580 <p>then only <code>Includes</code> will be set for the
3581 <code>/web/docs/spec</code> directory. However if the second
3582 <code class="directive">Options</code> directive uses the <code>+</code> and
3583 <code>-</code> symbols:</p>
3585 <pre class="prettyprint lang-config"><Directory "/web/docs">
3586 Options Indexes FollowSymLinks
3589 <Directory "/web/docs/spec">
3590 Options +Includes -Indexes
3591 </Directory></pre>
3594 <p>then the options <code>FollowSymLinks</code> and
3595 <code>Includes</code> are set for the <code>/web/docs/spec</code>
3598 <div class="note"><h3>Note</h3>
3599 <p>Using <code>-IncludesNOEXEC</code> or
3600 <code>-Includes</code> disables server-side includes completely
3601 regardless of the previous setting.</p>
3604 <p>The default in the absence of any other settings is
3605 <code>FollowSymlinks</code>.</p>
3608 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3609 <div class="directive-section"><h2><a name="Protocol" id="Protocol">Protocol</a> <a name="protocol" id="protocol">Directive</a></h2>
3610 <table class="directive">
3611 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Protocol for a listening socket</td></tr>
3612 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Protocol <var>protocol</var></code></td></tr>
3613 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3614 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3615 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3616 <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>
3618 <p>This directive specifies the protocol used for a specific listening socket.
3619 The protocol is used to determine which module should handle a request, and
3620 to apply protocol specific optimizations with the <code class="directive">AcceptFilter</code>
3623 <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>
3625 <p>For example, if you are running <code>https</code> on a non-standard port, specify the protocol explicitly:</p>
3627 <pre class="prettyprint lang-config">Protocol https</pre>
3630 <p>You can also specify the protocol using the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code> directive.</p>
3634 <li><code class="directive"><a href="#acceptfilter">AcceptFilter</a></code></li>
3635 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
3638 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3639 <div class="directive-section"><h2><a name="RegisterHttpMethod" id="RegisterHttpMethod">RegisterHttpMethod</a> <a name="registerhttpmethod" id="registerhttpmethod">Directive</a></h2>
3640 <table class="directive">
3641 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Register non-standard HTTP methods</td></tr>
3642 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>RegisterHttpMethod <var>method</var> [<var>method</var> [...]]</code></td></tr>
3643 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3644 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3645 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3647 <p>HTTP Methods that are not conforming to the relvant RFCs are normally
3648 rejected by request processing in Apache HTTPD. To avoid this, modules
3649 can register non-standard HTTP methods they support.
3650 The <code class="directive">RegisterHttpMethod</code> allows to register such
3651 methods manually. This can be useful for if such methods are forwared
3652 for external processing, e.g. to a CGI script.</p>
3655 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3656 <div class="directive-section"><h2><a name="RLimitCPU" id="RLimitCPU">RLimitCPU</a> <a name="rlimitcpu" id="rlimitcpu">Directive</a></h2>
3657 <table class="directive">
3658 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the CPU consumption of processes launched
3659 by Apache httpd children</td></tr>
3660 <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>
3661 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3662 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3663 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3664 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3665 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3667 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3668 resource limit for all processes and the second parameter sets
3669 the maximum resource limit. Either parameter can be a number,
3670 or <code>max</code> to indicate to the server that the limit should
3671 be set to the maximum allowed by the operating system
3672 configuration. Raising the maximum resource limit requires that
3673 the server is running as <code>root</code>, or in the initial startup
3676 <p>This applies to processes forked off from Apache httpd children
3677 servicing requests, not the Apache httpd children themselves. This
3678 includes CGI scripts and SSI exec commands, but not any
3679 processes forked off from the Apache httpd parent such as piped
3682 <p>CPU resource limits are expressed in seconds per
3687 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3688 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3691 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3692 <div class="directive-section"><h2><a name="RLimitMEM" id="RLimitMEM">RLimitMEM</a> <a name="rlimitmem" id="rlimitmem">Directive</a></h2>
3693 <table class="directive">
3694 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the memory consumption of processes launched
3695 by Apache httpd children</td></tr>
3696 <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>
3697 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3698 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3699 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3700 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3701 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3703 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3704 resource limit for all processes and the second parameter sets
3705 the maximum resource limit. Either parameter can be a number,
3706 or <code>max</code> to indicate to the server that the limit should
3707 be set to the maximum allowed by the operating system
3708 configuration. Raising the maximum resource limit requires that
3709 the server is running as <code>root</code>, or in the initial startup
3712 <p>This applies to processes forked off from Apache httpd children
3713 servicing requests, not the Apache httpd children themselves. This
3714 includes CGI scripts and SSI exec commands, but not any
3715 processes forked off from the Apache httpd parent such as piped
3718 <p>Memory resource limits are expressed in bytes per
3723 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3724 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3727 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3728 <div class="directive-section"><h2><a name="RLimitNPROC" id="RLimitNPROC">RLimitNPROC</a> <a name="rlimitnproc" id="rlimitnproc">Directive</a></h2>
3729 <table class="directive">
3730 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of processes that can be launched by
3731 processes launched by Apache httpd children</td></tr>
3732 <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>
3733 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3734 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3735 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3736 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3737 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3739 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3740 resource limit for all processes and the second parameter sets
3741 the maximum resource limit. Either parameter can be a number,
3742 or <code>max</code> to indicate to the server that the limit
3743 should be set to the maximum allowed by the operating system
3744 configuration. Raising the maximum resource limit requires that
3745 the server is running as <code>root</code>, or in the initial startup
3748 <p>This applies to processes forked off from Apache httpd children
3749 servicing requests, not the Apache httpd children themselves. This
3750 includes CGI scripts and SSI exec commands, but not any
3751 processes forked off from the Apache httpd parent such as piped
3754 <p>Process limits control the number of processes per user.</p>
3756 <div class="note"><h3>Note</h3>
3757 <p>If CGI processes are <strong>not</strong> running
3758 under user ids other than the web server user id, this directive
3759 will limit the number of processes that the server itself can
3760 create. Evidence of this situation will be indicated by
3761 <strong><code>cannot fork</code></strong> messages in the
3762 <code>error_log</code>.</p>
3767 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3768 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3771 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3772 <div class="directive-section"><h2><a name="ScriptInterpreterSource" id="ScriptInterpreterSource">ScriptInterpreterSource</a> <a name="scriptinterpretersource" id="scriptinterpretersource">Directive</a></h2>
3773 <table class="directive">
3774 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
3776 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ScriptInterpreterSource Registry|Registry-Strict|Script</code></td></tr>
3777 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ScriptInterpreterSource Script</code></td></tr>
3778 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3779 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3780 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3781 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3782 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Win32 only.</td></tr>
3784 <p>This directive is used to control how Apache httpd finds the
3785 interpreter used to run CGI scripts. The default setting is
3786 <code>Script</code>. This causes Apache httpd to use the interpreter pointed to
3787 by the shebang line (first line, starting with <code>#!</code>) in the
3788 script. On Win32 systems this line usually looks like:</p>
3790 <pre class="prettyprint lang-perl">#!C:/Perl/bin/perl.exe</pre>
3793 <p>or, if <code>perl</code> is in the <code>PATH</code>, simply:</p>
3795 <pre class="prettyprint lang-perl">#!perl</pre>
3798 <p>Setting <code>ScriptInterpreterSource Registry</code> will
3799 cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
3800 searched using the script file extension (e.g., <code>.pl</code>) as a
3801 search key. The command defined by the registry subkey
3802 <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
3803 <code>Shell\Open\Command</code> is used to open the script file. If the
3804 registry keys cannot be found, Apache httpd falls back to the behavior of the
3805 <code>Script</code> option.</p>
3807 <div class="warning"><h3>Security</h3>
3808 <p>Be careful when using <code>ScriptInterpreterSource
3809 Registry</code> with <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>'ed directories, because
3810 Apache httpd will try to execute <strong>every</strong> file within this
3811 directory. The <code>Registry</code> setting may cause undesired
3812 program calls on files which are typically not executed. For
3813 example, the default open command on <code>.htm</code> files on
3814 most Windows systems will execute Microsoft Internet Explorer, so
3815 any HTTP request for an <code>.htm</code> file existing within the
3816 script directory would start the browser in the background on the
3817 server. This is a good way to crash your system within a minute or
3821 <p>The option <code>Registry-Strict</code> which is new in Apache HTTP Server
3822 2.0 does the same thing as <code>Registry</code> but uses only the
3823 subkey <code>Shell\ExecCGI\Command</code>. The
3824 <code>ExecCGI</code> key is not a common one. It must be
3825 configured manually in the windows registry and hence prevents
3826 accidental program calls on your system.</p>
3829 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3830 <div class="directive-section"><h2><a name="SeeRequestTail" id="SeeRequestTail">SeeRequestTail</a> <a name="seerequesttail" id="seerequesttail">Directive</a></h2>
3831 <table class="directive">
3832 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine if mod_status displays the first 63 characters
3833 of a request or the last 63, assuming the request itself is greater than
3835 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SeeRequestTail On|Off</code></td></tr>
3836 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SeeRequestTail Off</code></td></tr>
3837 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3838 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3839 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3841 <p>mod_status with <code>ExtendedStatus On</code>
3842 displays the actual request being handled.
3843 For historical purposes, only 63 characters of the request
3844 are actually stored for display purposes. This directive
3845 controls whether the 1st 63 characters are stored (the previous
3846 behavior and the default) or if the last 63 characters are. This
3847 is only applicable, of course, if the length of the request is
3848 64 characters or greater.</p>
3850 <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:
3853 <table class="bordered">
3855 <th>Off (default)</th>
3856 <td>GET /disk1/storage/apache/htdocs/images/imagestore1/food/apples</td>
3860 <td>orage/apache/htdocs/images/imagestore1/food/apples.jpg HTTP/1.1</td>
3866 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3867 <div class="directive-section"><h2><a name="ServerAdmin" id="ServerAdmin">ServerAdmin</a> <a name="serveradmin" id="serveradmin">Directive</a></h2>
3868 <table class="directive">
3869 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Email address that the server includes in error
3870 messages sent to the client</td></tr>
3871 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAdmin <var>email-address</var>|<var>URL</var></code></td></tr>
3872 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3873 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3874 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3876 <p>The <code class="directive">ServerAdmin</code> sets the contact address
3877 that the server includes in any error messages it returns to the
3878 client. If the <code>httpd</code> doesn't recognize the supplied argument
3880 assumes, that it's an <var>email-address</var> and prepends it with
3881 <code>mailto:</code> in hyperlink targets. However, it's recommended to
3882 actually use an email address, since there are a lot of CGI scripts that
3883 make that assumption. If you want to use an URL, it should point to another
3884 server under your control. Otherwise users may not be able to contact you in
3887 <p>It may be worth setting up a dedicated address for this, e.g.</p>
3889 <pre class="prettyprint lang-config">ServerAdmin www-admin@foo.example.com</pre>
3891 <p>as users do not always mention that they are talking about the
3895 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3896 <div class="directive-section"><h2><a name="ServerAlias" id="ServerAlias">ServerAlias</a> <a name="serveralias" id="serveralias">Directive</a></h2>
3897 <table class="directive">
3898 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Alternate names for a host used when matching requests
3899 to name-virtual hosts</td></tr>
3900 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</code></td></tr>
3901 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
3902 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3903 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3905 <p>The <code class="directive">ServerAlias</code> directive sets the
3906 alternate names for a host, for use with <a href="../vhosts/name-based.html">name-based virtual hosts</a>. The
3907 <code class="directive">ServerAlias</code> may include wildcards, if appropriate.</p>
3909 <pre class="prettyprint lang-config"><VirtualHost *:80>
3910 ServerName server.example.com
3911 ServerAlias server server2.example.com server2
3912 ServerAlias *.example.com
3913 UseCanonicalName Off
3915 </VirtualHost></pre>
3918 <p>Name-based virtual hosts for the best-matching set of <code class="directive"><a href="#virtualhost"><virtualhost></a></code>s are processed
3919 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
3920 (nor for ServerName vs. ServerAlias). </p>
3922 <p>The complete list of names in the <code class="directive">VirtualHost</code>
3923 directive are treated just like a (non wildcard)
3924 <code class="directive">ServerAlias</code>.</p>
3929 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3930 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
3933 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3934 <div class="directive-section"><h2><a name="ServerName" id="ServerName">ServerName</a> <a name="servername" id="servername">Directive</a></h2>
3935 <table class="directive">
3936 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hostname and port that the server uses to identify
3938 <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>
3939 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3940 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3941 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3943 <p>The <code class="directive">ServerName</code> directive sets the
3944 request scheme, hostname and
3945 port that the server uses to identify itself. This is used when
3946 creating redirection URLs.</p>
3948 <p>Additionally, <code class="directive">ServerName</code> is used (possibly
3949 in conjunction with <code class="directive">ServerAlias</code>) to uniquely
3950 identify a virtual host, when using <a href="../vhosts/name-based.html">name-based virtual hosts</a>.</p>
3952 <p>For example, if the name of the
3953 machine hosting the web server is <code>simple.example.com</code>,
3954 but the machine also has the DNS alias <code>www.example.com</code>
3955 and you wish the web server to be so identified, the following
3956 directive should be used:</p>
3958 <pre class="prettyprint lang-config">ServerName www.example.com</pre>
3961 <p>The <code class="directive">ServerName</code> directive
3962 may appear anywhere within the definition of a server. However,
3963 each appearance overrides the previous appearance (within that
3966 <p>If no <code class="directive">ServerName</code> is specified, then the
3967 server attempts to deduce the client visible hostname by performing a
3968 reverse lookup on an IP address of the systems hostname.</p>
3970 <p>If no port is specified in the
3971 <code class="directive">ServerName</code>, then the server will use the
3972 port from the incoming request. For optimal reliability and
3973 predictability, you should specify an explicit hostname and port
3974 using the <code class="directive">ServerName</code> directive.</p>
3976 <p>If you are using <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
3977 the <code class="directive">ServerName</code> inside a
3978 <code class="directive"><a href="#virtualhost"><VirtualHost></a></code>
3979 section specifies what hostname must appear in the request's
3980 <code>Host:</code> header to match this virtual host.</p>
3982 <p>Sometimes, the server runs behind a device that processes SSL,
3983 such as a reverse proxy, load balancer or SSL offload
3984 appliance. When this is the case, specify the
3985 <code>https://</code> scheme and the port number to which the
3986 clients connect in the <code class="directive">ServerName</code> directive
3987 to make sure that the server generates the correct
3988 self-referential URLs.
3991 <p>See the description of the
3992 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> and
3993 <code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code> directives for
3994 settings which determine whether self-referential URLs (e.g., by the
3995 <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> module) will refer to the
3996 specified port, or to the port number given in the client's request.
3999 <div class="warning">
4000 <p>Failure to set <code class="directive">ServerName</code> to a name that
4001 your server can resolve to an IP address will result in a startup
4002 warning. <code>httpd</code> will then use whatever hostname it can
4003 determine, using the system's <code>hostname</code> command. This
4004 will almost never be the hostname you actually want.</p>
4005 <div class="example"><p><code>
4006 httpd: Could not reliably determine the server's fully qualified domain name, using rocinante.local for ServerName
4013 <li><a href="../dns-caveats.html">Issues Regarding DNS and
4014 Apache HTTP Server</a></li>
4015 <li><a href="../vhosts/">Apache HTTP Server virtual host
4016 documentation</a></li>
4017 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
4018 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
4019 <li><code class="directive"><a href="#serveralias">ServerAlias</a></code></li>
4022 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4023 <div class="directive-section"><h2><a name="ServerPath" id="ServerPath">ServerPath</a> <a name="serverpath" id="serverpath">Directive</a></h2>
4024 <table class="directive">
4025 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Legacy URL pathname for a name-based virtual host that
4026 is accessed by an incompatible browser</td></tr>
4027 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerPath <var>URL-path</var></code></td></tr>
4028 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
4029 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4030 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4032 <p>The <code class="directive">ServerPath</code> directive sets the legacy
4033 URL pathname for a host, for use with <a href="../vhosts/">name-based virtual hosts</a>.</p>
4037 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4040 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4041 <div class="directive-section"><h2><a name="ServerRoot" id="ServerRoot">ServerRoot</a> <a name="serverroot" id="serverroot">Directive</a></h2>
4042 <table class="directive">
4043 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server installation</td></tr>
4044 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerRoot <var>directory-path</var></code></td></tr>
4045 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerRoot /usr/local/apache</code></td></tr>
4046 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4047 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4048 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4050 <p>The <code class="directive">ServerRoot</code> directive sets the
4051 directory in which the server lives. Typically it will contain the
4052 subdirectories <code>conf/</code> and <code>logs/</code>. Relative
4053 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
4054 relative to this directory.</p>
4056 <pre class="prettyprint lang-config">ServerRoot "/home/httpd"</pre>
4059 <p>The default location of <code class="directive">ServerRoot</code> may be
4060 modified by using the <code>--prefix</code> argument to
4061 <a href="../programs/configure.html"><code>configure</code></a>, and
4062 most third-party distributions of the server have a different
4063 default location from the one listed above.</p>
4068 <li><a href="../invoking.html">the <code>-d</code>
4069 option to <code>httpd</code></a></li>
4070 <li><a href="../misc/security_tips.html#serverroot">the
4071 security tips</a> for information on how to properly set
4072 permissions on the <code class="directive">ServerRoot</code></li>
4075 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4076 <div class="directive-section"><h2><a name="ServerSignature" id="ServerSignature">ServerSignature</a> <a name="serversignature" id="serversignature">Directive</a></h2>
4077 <table class="directive">
4078 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the footer on server-generated documents</td></tr>
4079 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerSignature On|Off|EMail</code></td></tr>
4080 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerSignature Off</code></td></tr>
4081 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4082 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
4083 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4084 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4086 <p>The <code class="directive">ServerSignature</code> directive allows the
4087 configuration of a trailing footer line under server-generated
4088 documents (error messages, <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> ftp directory
4089 listings, <code class="module"><a href="../mod/mod_info.html">mod_info</a></code> output, ...). The reason why you
4090 would want to enable such a footer line is that in a chain of proxies,
4091 the user often has no possibility to tell which of the chained servers
4092 actually produced a returned error message.</p>
4094 <p>The <code>Off</code>
4095 setting, which is the default, suppresses the footer line (and is
4096 therefore compatible with the behavior of Apache-1.2 and
4097 below). The <code>On</code> setting simply adds a line with the
4098 server version number and <code class="directive"><a href="#servername">ServerName</a></code> of the serving virtual host,
4099 and the <code>EMail</code> setting additionally creates a
4100 "mailto:" reference to the <code class="directive"><a href="#serveradmin">ServerAdmin</a></code> of the referenced
4103 <p>After version 2.0.44, the details of the server version number
4104 presented are controlled by the <code class="directive"><a href="#servertokens">ServerTokens</a></code> directive.</p>
4108 <li><code class="directive"><a href="#servertokens">ServerTokens</a></code></li>
4111 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4112 <div class="directive-section"><h2><a name="ServerTokens" id="ServerTokens">ServerTokens</a> <a name="servertokens" id="servertokens">Directive</a></h2>
4113 <table class="directive">
4114 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the <code>Server</code> HTTP response
4116 <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>
4117 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerTokens Full</code></td></tr>
4118 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4119 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4120 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4122 <p>This directive controls whether <code>Server</code> response
4123 header field which is sent back to clients includes a
4124 description of the generic OS-type of the server as well as
4125 information about compiled-in modules.</p>
4128 <dt><code>ServerTokens Full</code> (or not specified)</dt>
4130 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4131 (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
4133 <dt><code>ServerTokens Prod[uctOnly]</code></dt>
4135 <dd>Server sends (<em>e.g.</em>): <code>Server:
4138 <dt><code>ServerTokens Major</code></dt>
4140 <dd>Server sends (<em>e.g.</em>): <code>Server:
4141 Apache/2</code></dd>
4143 <dt><code>ServerTokens Minor</code></dt>
4145 <dd>Server sends (<em>e.g.</em>): <code>Server:
4146 Apache/2.4</code></dd>
4148 <dt><code>ServerTokens Min[imal]</code></dt>
4150 <dd>Server sends (<em>e.g.</em>): <code>Server:
4151 Apache/2.4.2</code></dd>
4153 <dt><code>ServerTokens OS</code></dt>
4155 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4160 <p>This setting applies to the entire server, and cannot be
4161 enabled or disabled on a virtualhost-by-virtualhost basis.</p>
4163 <p>After version 2.0.44, this directive also controls the
4164 information presented by the <code class="directive"><a href="#serversignature">ServerSignature</a></code> directive.</p>
4166 <div class="note">Setting <code class="directive">ServerTokens</code> to less than
4167 <code>minimal</code> is not recommended because it makes it more
4168 difficult to debug interoperational problems. Also note that
4169 disabling the Server: header does nothing at all to make your
4170 server more secure; the idea of "security through obscurity"
4171 is a myth and leads to a false sense of safety.</div>
4176 <li><code class="directive"><a href="#serversignature">ServerSignature</a></code></li>
4179 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4180 <div class="directive-section"><h2><a name="SetHandler" id="SetHandler">SetHandler</a> <a name="sethandler" id="sethandler">Directive</a></h2>
4181 <table class="directive">
4182 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be processed by a
4184 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetHandler <var>handler-name</var>|None</code></td></tr>
4185 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4186 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4187 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4188 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4190 <p>When placed into an <code>.htaccess</code> file or a
4191 <code class="directive"><a href="#directory"><Directory></a></code> or
4192 <code class="directive"><a href="#location"><Location></a></code>
4193 section, this directive forces all matching files to be parsed
4194 through the <a href="../handler.html">handler</a> given by
4195 <var>handler-name</var>. For example, if you had a directory you
4196 wanted to be parsed entirely as imagemap rule files, regardless
4197 of extension, you might put the following into an
4198 <code>.htaccess</code> file in that directory:</p>
4200 <pre class="prettyprint lang-config">SetHandler imap-file</pre>
4203 <p>Another example: if you wanted to have the server display a
4204 status report whenever a URL of
4205 <code>http://servername/status</code> was called, you might put
4206 the following into <code>httpd.conf</code>:</p>
4208 <pre class="prettyprint lang-config"><Location "/status">
4209 SetHandler server-status
4210 </Location></pre>
4213 <p>You could also use this directive to configure a particular
4214 handler for files with a particular file extension. For example:</p>
4216 <pre class="prettyprint lang-config"><FilesMatch \.php$>
4217 SetHandler application/x-httpd-php
4218 </FilesMatch></pre>
4221 <p>You can override an earlier defined <code class="directive">SetHandler</code>
4222 directive by using the value <code>None</code>.</p>
4224 <div class="note"><h3>Note</h3>
4225 <p>Because <code class="directive">SetHandler</code> overrides default handlers,
4226 normal behavior such as handling of URLs ending in a slash (/) as
4227 directories or index files is suppressed.</p></div>
4231 <li><code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code></li>
4234 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4235 <div class="directive-section"><h2><a name="SetInputFilter" id="SetInputFilter">SetInputFilter</a> <a name="setinputfilter" id="setinputfilter">Directive</a></h2>
4236 <table class="directive">
4237 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process client requests and POST
4239 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetInputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4240 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4241 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4242 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4243 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4245 <p>The <code class="directive">SetInputFilter</code> directive sets the
4246 filter or filters which will process client requests and POST
4247 input when they are received by the server. This is in addition to
4248 any filters defined elsewhere, including the
4249 <code class="directive"><a href="../mod/mod_mime.html#addinputfilter">AddInputFilter</a></code>
4252 <p>If more than one filter is specified, they must be separated
4253 by semicolons in the order in which they should process the
4258 <li><a href="../filter.html">Filters</a> documentation</li>
4261 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4262 <div class="directive-section"><h2><a name="SetOutputFilter" id="SetOutputFilter">SetOutputFilter</a> <a name="setoutputfilter" id="setoutputfilter">Directive</a></h2>
4263 <table class="directive">
4264 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process responses from the
4266 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4267 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4268 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4269 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4270 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4272 <p>The <code class="directive">SetOutputFilter</code> directive sets the filters
4273 which will process responses from the server before they are
4274 sent to the client. This is in addition to any filters defined
4275 elsewhere, including the
4276 <code class="directive"><a href="../mod/mod_mime.html#addoutputfilter">AddOutputFilter</a></code>
4279 <p>For example, the following configuration will process all files
4280 in the <code>/www/data/</code> directory for server-side
4283 <pre class="prettyprint lang-config"><Directory "/www/data/">
4284 SetOutputFilter INCLUDES
4285 </Directory></pre>
4288 <p>If more than one filter is specified, they must be separated
4289 by semicolons in the order in which they should process the
4294 <li><a href="../filter.html">Filters</a> documentation</li>
4297 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4298 <div class="directive-section"><h2><a name="TimeOut" id="TimeOut">TimeOut</a> <a name="timeout" id="timeout">Directive</a></h2>
4299 <table class="directive">
4300 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for
4301 certain events before failing a request</td></tr>
4302 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TimeOut <var>seconds</var></code></td></tr>
4303 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TimeOut 60</code></td></tr>
4304 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4305 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4306 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4308 <p>The <code class="directive">TimeOut</code> directive defines the length
4309 of time Apache httpd will wait for I/O in various circumstances:</p>
4312 <li>When reading data from the client, the length of time to
4313 wait for a TCP packet to arrive if the read buffer is
4316 <li>When writing data to the client, the length of time to wait
4317 for an acknowledgement of a packet if the send buffer is
4320 <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>,
4321 the length of time to wait for output from a CGI script.</li>
4323 <li>In <code class="module"><a href="../mod/mod_ext_filter.html">mod_ext_filter</a></code>, the length of time to
4324 wait for output from a filtering process.</li>
4326 <li>In <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>, the default timeout value if
4327 <code class="directive"><a href="../mod/mod_proxy.html#proxytimeout">ProxyTimeout</a></code> is not
4333 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4334 <div class="directive-section"><h2><a name="TraceEnable" id="TraceEnable">TraceEnable</a> <a name="traceenable" id="traceenable">Directive</a></h2>
4335 <table class="directive">
4336 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines the behavior on <code>TRACE</code> requests</td></tr>
4337 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TraceEnable <var>[on|off|extended]</var></code></td></tr>
4338 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TraceEnable on</code></td></tr>
4339 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4340 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4341 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4343 <p>This directive overrides the behavior of <code>TRACE</code> for both
4344 the core server and <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>. The default
4345 <code>TraceEnable on</code> permits <code>TRACE</code> requests per
4346 RFC 2616, which disallows any request body to accompany the request.
4347 <code>TraceEnable off</code> causes the core server and
4348 <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> to return a <code>405</code> (Method not
4349 allowed) error to the client.</p>
4351 <p>Finally, for testing and diagnostic purposes only, request
4352 bodies may be allowed using the non-compliant <code>TraceEnable
4353 extended</code> directive. The core (as an origin server) will
4354 restrict the request body to 64k (plus 8k for chunk headers if
4355 <code>Transfer-Encoding: chunked</code> is used). The core will
4356 reflect the full headers and all chunk headers with the response
4357 body. As a proxy server, the request body is not restricted to 64k.</p>
4359 <div class="note"><h3>Note</h3>
4360 <p>Despite claims to the contrary, <code>TRACE</code> is not
4361 a security vulnerability and there is no viable reason for
4362 it to be disabled. Doing so necessarily makes your server
4367 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4368 <div class="directive-section"><h2><a name="UnDefine" id="UnDefine">UnDefine</a> <a name="undefine" id="undefine">Directive</a></h2>
4369 <table class="directive">
4370 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Undefine the existence of a variable</td></tr>
4371 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UnDefine <var>parameter-name</var></code></td></tr>
4372 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4373 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4374 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4376 <p>Undoes the effect of a <code class="directive"><a href="#define">Define</a></code> or
4377 of passing a <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</p>
4378 <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
4379 <code>-D</code> arguments in any startup scripts.</p>
4380 <p>While this directive is supported in virtual host context,
4381 the changes it makes are visible to any later configuration
4382 directives, beyond any enclosing virtual host</p>
4385 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4386 <div class="directive-section"><h2><a name="UseCanonicalName" id="UseCanonicalName">UseCanonicalName</a> <a name="usecanonicalname" id="usecanonicalname">Directive</a></h2>
4387 <table class="directive">
4388 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own name and
4390 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalName On|Off|DNS</code></td></tr>
4391 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalName Off</code></td></tr>
4392 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4393 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4394 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4396 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4397 URL -- that is, a URL that refers back to the same server. With
4398 <code>UseCanonicalName On</code> Apache httpd will use the hostname and port
4399 specified in the <code class="directive"><a href="#servername">ServerName</a></code>
4400 directive to construct the canonical name for the server. This name
4401 is used in all self-referential URLs, and for the values of
4402 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>
4404 <p>With <code>UseCanonicalName Off</code> Apache httpd will form
4405 self-referential URLs using the hostname and port supplied by
4406 the client if any are supplied (otherwise it will use the
4407 canonical name, as defined above). These values are the same
4408 that are used to implement <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
4409 and are available with the same clients. The CGI variables
4410 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
4411 constructed from the client supplied values as well.</p>
4413 <p>An example where this may be useful is on an intranet server
4414 where you have users connecting to the machine using short
4415 names such as <code>www</code>. You'll notice that if the users
4416 type a shortname, and a URL which is a directory, such as
4417 <code>http://www/splat</code>, <em>without the trailing
4418 slash</em> then Apache httpd will redirect them to
4419 <code>http://www.example.com/splat/</code>. If you have
4420 authentication enabled, this will cause the user to have to
4421 authenticate twice (once for <code>www</code> and once again
4422 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">
4423 the FAQ on this subject for more information</a>). But if
4424 <code class="directive">UseCanonicalName</code> is set <code>Off</code>, then
4425 Apache httpd will redirect to <code>http://www/splat/</code>.</p>
4427 <p>There is a third option, <code>UseCanonicalName DNS</code>,
4428 which is intended for use with mass IP-based virtual hosting to
4429 support ancient clients that do not provide a
4430 <code>Host:</code> header. With this option Apache httpd does a
4431 reverse DNS lookup on the server IP address that the client
4432 connected to in order to work out self-referential URLs.</p>
4434 <div class="warning"><h3>Warning</h3>
4435 <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>
4436 they may be broken by this option. The client is essentially free
4437 to give whatever value they want as a hostname. But if the CGI is
4438 only using <code>SERVER_NAME</code> to construct self-referential URLs
4439 then it should be just fine.</p>
4444 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
4445 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4446 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4449 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4450 <div class="directive-section"><h2><a name="UseCanonicalPhysicalPort" id="UseCanonicalPhysicalPort">UseCanonicalPhysicalPort</a> <a name="usecanonicalphysicalport" id="usecanonicalphysicalport">Directive</a></h2>
4451 <table class="directive">
4452 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own port</td></tr>
4453 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalPhysicalPort On|Off</code></td></tr>
4454 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalPhysicalPort Off</code></td></tr>
4455 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4456 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4457 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4459 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4460 URL -- that is, a URL that refers back to the same server. With
4461 <code>UseCanonicalPhysicalPort On</code> Apache httpd will, when
4462 constructing the canonical port for the server to honor
4463 the <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> directive,
4464 provide the actual physical port number being used by this request
4465 as a potential port. With <code>UseCanonicalPhysicalPort Off</code>
4466 Apache httpd will not ever use the actual physical port number, instead
4467 relying on all configured information to construct a valid port number.</p>
4469 <div class="note"><h3>Note</h3>
4470 <p>The ordering of the lookup when the physical port is used is as
4473 <dt><code>UseCanonicalName On</code></dt>
4476 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4477 <li>Physical port</li>
4478 <li>Default port</li>
4481 <dt><code>UseCanonicalName Off | DNS</code></dt>
4484 <li>Parsed port from <code>Host:</code> header</li>
4485 <li>Physical port</li>
4486 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4487 <li>Default port</li>
4492 <p>With <code>UseCanonicalPhysicalPort Off</code>, the
4493 physical ports are removed from the ordering.</p>
4499 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
4500 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4501 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4504 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4505 <div class="directive-section"><h2><a name="VirtualHost" id="VirtualHost"><VirtualHost></a> <a name="virtualhost" id="virtualhost">Directive</a></h2>
4506 <table class="directive">
4507 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only to a specific
4508 hostname or IP address</td></tr>
4509 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><VirtualHost
4510 <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
4511 ...> ... </VirtualHost></code></td></tr>
4512 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4513 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4514 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4516 <p><code class="directive"><VirtualHost></code> and
4517 <code></VirtualHost></code> are used to enclose a group of
4518 directives that will apply only to a particular virtual host. Any
4519 directive that is allowed in a virtual host context may be
4520 used. When the server receives a request for a document on a
4521 particular virtual host, it uses the configuration directives
4522 enclosed in the <code class="directive"><VirtualHost></code>
4523 section. <var>Addr</var> can be any of the following, optionally followed by
4524 a colon and a port number (or *):</p>
4527 <li>The IP address of the virtual host;</li>
4529 <li>A fully qualified domain name for the IP address of the
4530 virtual host (not recommended);</li>
4532 <li>The character <code>*</code>, which acts as a wildcard and matches
4533 any IP address.</li>
4535 <li>The string <code>_default_</code>, which is an alias for <code>*</code></li>
4539 <pre class="prettyprint lang-config"><VirtualHost 10.1.2.3:80>
4540 ServerAdmin webmaster@host.example.com
4541 DocumentRoot /www/docs/host.example.com
4542 ServerName host.example.com
4543 ErrorLog logs/host.example.com-error_log
4544 TransferLog logs/host.example.com-access_log
4545 </VirtualHost></pre>
4549 <p>IPv6 addresses must be specified in square brackets because
4550 the optional port number could not be determined otherwise. An
4551 IPv6 example is shown below:</p>
4553 <pre class="prettyprint lang-config"><VirtualHost [2001:db8::a00:20ff:fea7:ccea]:80>
4554 ServerAdmin webmaster@host.example.com
4555 DocumentRoot /www/docs/host.example.com
4556 ServerName host.example.com
4557 ErrorLog logs/host.example.com-error_log
4558 TransferLog logs/host.example.com-access_log
4559 </VirtualHost></pre>
4562 <p>Each Virtual Host must correspond to a different IP address,
4563 different port number or a different host name for the server,
4564 in the former case the server machine must be configured to
4565 accept IP packets for multiple addresses. (If the machine does
4566 not have multiple network interfaces, then this can be
4567 accomplished with the <code>ifconfig alias</code> command -- if
4568 your OS supports it).</p>
4570 <div class="note"><h3>Note</h3>
4571 <p>The use of <code class="directive"><VirtualHost></code> does
4572 <strong>not</strong> affect what addresses Apache httpd listens on. You
4573 may need to ensure that Apache httpd is listening on the correct addresses
4574 using <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>.</p>
4577 <p>A <code class="directive"><a href="#servername">ServerName</a></code> should be
4578 specified inside each <code class="directive"><VirtualHost></code> block. If it is absent, the
4579 <code class="directive"><a href="#servername">ServerName</a></code> from the "main"
4580 server configuration will be inherited.</p>
4582 <p>When a request is received, the server first maps it to the best matching
4583 <code class="directive"><VirtualHost></code> based on the local
4584 IP address and port combination only. Non-wildcards have a higher
4585 precedence. If no match based on IP and port occurs at all, the
4586 "main" server configuration is used.</p>
4588 <p>If multiple virtual hosts contain the best matching IP address and port,
4589 the server selects from these virtual hosts the best match based on the
4590 requested hostname. If no matching name-based virtual host is found,
4591 then the first listed virtual host that matched the IP address will be
4592 used. As a consequence, the first listed virtual host for a given IP address
4593 and port combination is default virtual host for that IP and port
4596 <div class="warning"><h3>Security</h3>
4597 <p>See the <a href="../misc/security_tips.html">security tips</a>
4598 document for details on why your security could be compromised if the
4599 directory where log files are stored is writable by anyone other
4600 than the user that starts the server.</p>
4605 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4606 <li><a href="../dns-caveats.html">Issues Regarding DNS and
4607 Apache HTTP Server</a></li>
4608 <li><a href="../bind.html">Setting
4609 which addresses and ports Apache HTTP Server uses</a></li>
4610 <li><a href="../sections.html">How <Directory>, <Location>
4611 and <Files> sections work</a> for an explanation of how these
4612 different sections are combined when a request is received</li>
4615 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4616 <div class="directive-section"><h2><a name="Warning" id="Warning">Warning</a> <a name="warning" id="warning">Directive</a></h2>
4617 <table class="directive">
4618 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Warn from configuration parsing with a custom message</td></tr>
4619 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Warning <var>message</var></code></td></tr>
4620 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4621 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4622 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4623 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.5 and later</td></tr>
4625 <p>If an issue can be detected from within the configuration, this
4626 directive can be used to generate a custom warning message. The
4627 configuration parsing is not halted. The typical use it to check
4628 whether some user define options are set, and warn if not.</p>
4630 <pre class="prettyprint lang-config"># Example
4631 # tell when ReverseProxy is not set
4632 <IfDefine !ReverseProxy>
4633 Warning "reverse proxy is not started, hope this is okay!"
4636 <IfDefine ReverseProxy>
4637 # define custom proxy configuration
4638 </IfDefine></pre>
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