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18 <p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/quickreference.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p>
19 <p class="apache">Apache HTTP Server Version 2.5</p>
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23 <a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.5</a> > <a href="./">Modules</a></div>
24 <div id="page-content">
25 <div id="preamble"><h1>Apache Core Features</h1>
27 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
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34 <table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Core Apache HTTP Server features that are always
36 <tr><th><a href="module-dict.html#Status">Status:</a></th><td>Core</td></tr></table>
38 <div id="quickview"><h3 class="directives">Directives</h3>
40 <li><img alt="" src="../images/down.gif" /> <a href="#acceptfilter">AcceptFilter</a></li>
41 <li><img alt="" src="../images/down.gif" /> <a href="#acceptpathinfo">AcceptPathInfo</a></li>
42 <li><img alt="" src="../images/down.gif" /> <a href="#accessfilename">AccessFileName</a></li>
43 <li><img alt="" src="../images/down.gif" /> <a href="#adddefaultcharset">AddDefaultCharset</a></li>
44 <li><img alt="" src="../images/down.gif" /> <a href="#allowencodedslashes">AllowEncodedSlashes</a></li>
45 <li><img alt="" src="../images/down.gif" /> <a href="#allowoverride">AllowOverride</a></li>
46 <li><img alt="" src="../images/down.gif" /> <a href="#allowoverridelist">AllowOverrideList</a></li>
47 <li><img alt="" src="../images/down.gif" /> <a href="#cgimapextension">CGIMapExtension</a></li>
48 <li><img alt="" src="../images/down.gif" /> <a href="#contentdigest">ContentDigest</a></li>
49 <li><img alt="" src="../images/down.gif" /> <a href="#defaultruntimedir">DefaultRuntimeDir</a></li>
50 <li><img alt="" src="../images/down.gif" /> <a href="#defaulttype">DefaultType</a></li>
51 <li><img alt="" src="../images/down.gif" /> <a href="#define">Define</a></li>
52 <li><img alt="" src="../images/down.gif" /> <a href="#directory"><Directory></a></li>
53 <li><img alt="" src="../images/down.gif" /> <a href="#directorymatch"><DirectoryMatch></a></li>
54 <li><img alt="" src="../images/down.gif" /> <a href="#documentroot">DocumentRoot</a></li>
55 <li><img alt="" src="../images/down.gif" /> <a href="#else"><Else></a></li>
56 <li><img alt="" src="../images/down.gif" /> <a href="#elseif"><ElseIf></a></li>
57 <li><img alt="" src="../images/down.gif" /> <a href="#enablemmap">EnableMMAP</a></li>
58 <li><img alt="" src="../images/down.gif" /> <a href="#enablesendfile">EnableSendfile</a></li>
59 <li><img alt="" src="../images/down.gif" /> <a href="#error">Error</a></li>
60 <li><img alt="" src="../images/down.gif" /> <a href="#errordocument">ErrorDocument</a></li>
61 <li><img alt="" src="../images/down.gif" /> <a href="#errorlog">ErrorLog</a></li>
62 <li><img alt="" src="../images/down.gif" /> <a href="#errorlogformat">ErrorLogFormat</a></li>
63 <li><img alt="" src="../images/down.gif" /> <a href="#extendedstatus">ExtendedStatus</a></li>
64 <li><img alt="" src="../images/down.gif" /> <a href="#fileetag">FileETag</a></li>
65 <li><img alt="" src="../images/down.gif" /> <a href="#files"><Files></a></li>
66 <li><img alt="" src="../images/down.gif" /> <a href="#filesmatch"><FilesMatch></a></li>
67 <li><img alt="" src="../images/down.gif" /> <a href="#forcetype">ForceType</a></li>
68 <li><img alt="" src="../images/down.gif" /> <a href="#gprofdir">GprofDir</a></li>
69 <li><img alt="" src="../images/down.gif" /> <a href="#hostnamelookups">HostnameLookups</a></li>
70 <li><img alt="" src="../images/down.gif" /> <a href="#if"><If></a></li>
71 <li><img alt="" src="../images/down.gif" /> <a href="#ifdefine"><IfDefine></a></li>
72 <li><img alt="" src="../images/down.gif" /> <a href="#ifmodule"><IfModule></a></li>
73 <li><img alt="" src="../images/down.gif" /> <a href="#include">Include</a></li>
74 <li><img alt="" src="../images/down.gif" /> <a href="#includeoptional">IncludeOptional</a></li>
75 <li><img alt="" src="../images/down.gif" /> <a href="#keepalive">KeepAlive</a></li>
76 <li><img alt="" src="../images/down.gif" /> <a href="#keepalivetimeout">KeepAliveTimeout</a></li>
77 <li><img alt="" src="../images/down.gif" /> <a href="#limit"><Limit></a></li>
78 <li><img alt="" src="../images/down.gif" /> <a href="#limitexcept"><LimitExcept></a></li>
79 <li><img alt="" src="../images/down.gif" /> <a href="#limitinternalrecursion">LimitInternalRecursion</a></li>
80 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestbody">LimitRequestBody</a></li>
81 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfields">LimitRequestFields</a></li>
82 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfieldsize">LimitRequestFieldSize</a></li>
83 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestline">LimitRequestLine</a></li>
84 <li><img alt="" src="../images/down.gif" /> <a href="#limitxmlrequestbody">LimitXMLRequestBody</a></li>
85 <li><img alt="" src="../images/down.gif" /> <a href="#location"><Location></a></li>
86 <li><img alt="" src="../images/down.gif" /> <a href="#locationmatch"><LocationMatch></a></li>
87 <li><img alt="" src="../images/down.gif" /> <a href="#loglevel">LogLevel</a></li>
88 <li><img alt="" src="../images/down.gif" /> <a href="#logleveloverride">LogLevelOverride</a></li>
89 <li><img alt="" src="../images/down.gif" /> <a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></li>
90 <li><img alt="" src="../images/down.gif" /> <a href="#maxrangeoverlaps">MaxRangeOverlaps</a></li>
91 <li><img alt="" src="../images/down.gif" /> <a href="#maxrangereversals">MaxRangeReversals</a></li>
92 <li><img alt="" src="../images/down.gif" /> <a href="#maxranges">MaxRanges</a></li>
93 <li><img alt="" src="../images/down.gif" /> <a href="#mutex">Mutex</a></li>
94 <li><img alt="" src="../images/down.gif" /> <a href="#namevirtualhost">NameVirtualHost</a></li>
95 <li><img alt="" src="../images/down.gif" /> <a href="#options">Options</a></li>
96 <li><img alt="" src="../images/down.gif" /> <a href="#protocol">Protocol</a></li>
97 <li><img alt="" src="../images/down.gif" /> <a href="#registerhttpmethod">RegisterHttpMethod</a></li>
98 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitcpu">RLimitCPU</a></li>
99 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitmem">RLimitMEM</a></li>
100 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitnproc">RLimitNPROC</a></li>
101 <li><img alt="" src="../images/down.gif" /> <a href="#scriptinterpretersource">ScriptInterpreterSource</a></li>
102 <li><img alt="" src="../images/down.gif" /> <a href="#seerequesttail">SeeRequestTail</a></li>
103 <li><img alt="" src="../images/down.gif" /> <a href="#serveradmin">ServerAdmin</a></li>
104 <li><img alt="" src="../images/down.gif" /> <a href="#serveralias">ServerAlias</a></li>
105 <li><img alt="" src="../images/down.gif" /> <a href="#servername">ServerName</a></li>
106 <li><img alt="" src="../images/down.gif" /> <a href="#serverpath">ServerPath</a></li>
107 <li><img alt="" src="../images/down.gif" /> <a href="#serverroot">ServerRoot</a></li>
108 <li><img alt="" src="../images/down.gif" /> <a href="#serversignature">ServerSignature</a></li>
109 <li><img alt="" src="../images/down.gif" /> <a href="#servertokens">ServerTokens</a></li>
110 <li><img alt="" src="../images/down.gif" /> <a href="#sethandler">SetHandler</a></li>
111 <li><img alt="" src="../images/down.gif" /> <a href="#setinputfilter">SetInputFilter</a></li>
112 <li><img alt="" src="../images/down.gif" /> <a href="#setoutputfilter">SetOutputFilter</a></li>
113 <li><img alt="" src="../images/down.gif" /> <a href="#timeout">TimeOut</a></li>
114 <li><img alt="" src="../images/down.gif" /> <a href="#traceenable">TraceEnable</a></li>
115 <li><img alt="" src="../images/down.gif" /> <a href="#undefine">UnDefine</a></li>
116 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalname">UseCanonicalName</a></li>
117 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></li>
118 <li><img alt="" src="../images/down.gif" /> <a href="#virtualhost"><VirtualHost></a></li>
119 <li><img alt="" src="../images/down.gif" /> <a href="#warning">Warning</a></li>
121 <ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div>
123 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
124 <div class="directive-section"><h2><a name="AcceptFilter" id="AcceptFilter">AcceptFilter</a> <a name="acceptfilter" id="acceptfilter">Directive</a></h2>
125 <table class="directive">
126 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures optimizations for a Protocol's Listener Sockets</td></tr>
127 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptFilter <var>protocol</var> <var>accept_filter</var></code></td></tr>
128 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
129 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
130 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
131 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>On Windows only available from Apache httpd 2.3.3 and later.
134 <p>This directive enables operating system specific optimizations for a
135 listening socket by the <code class="directive">Protocol</code> type.
136 The basic premise is for the kernel to not send a socket to the server
137 process until either data is received or an entire HTTP Request is buffered.
138 Only <a href="http://www.freebsd.org/cgi/man.cgi?query=accept_filter&sektion=9">
139 FreeBSD's Accept Filters</a>, Linux's more primitive
140 <code>TCP_DEFER_ACCEPT</code>, and Windows' optimized AcceptEx()
141 are currently supported.</p>
143 <p>Using <code>none</code> for an argument will disable any accept filters
144 for that protocol. This is useful for protocols that require a server
145 send data first, such as <code>ftp:</code> or <code>nntp</code>:</p>
146 <pre class="prettyprint lang-config">
147 AcceptFilter nntp none
151 <p>The default protocol names are <code>https</code> for port 443
152 and <code>http</code> for all other ports. To specify another protocol
153 is being used with a listening port, add the <var>protocol</var>
154 argument to the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>
157 <p>The default values on FreeBSD are:</p>
158 <pre class="prettyprint lang-config">
159 AcceptFilter http httpready
160 AcceptFilter https dataready
164 <p>The <code>httpready</code> accept filter buffers entire HTTP requests at
165 the kernel level. Once an entire request is received, the kernel then
166 sends it to the server. See the
167 <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_http&sektion=9">
168 accf_http(9)</a> man page for more details. Since HTTPS requests are
169 encrypted only the <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_data&sektion=9">
170 accf_data(9)</a> filter is used.</p>
172 <p>The default values on Linux are:</p>
173 <pre class="prettyprint lang-config">
174 AcceptFilter http data
175 AcceptFilter https data
179 <p>Linux's <code>TCP_DEFER_ACCEPT</code> does not support buffering http
180 requests. Any value besides <code>none</code> will enable
181 <code>TCP_DEFER_ACCEPT</code> on that listener. For more details
183 <a href="http://homepages.cwi.nl/~aeb/linux/man2html/man7/tcp.7.html">
184 tcp(7)</a> man page.</p>
186 <p>The default values on Windows are:</p>
187 <pre class="prettyprint lang-config">
188 AcceptFilter http data
189 AcceptFilter https data
193 <p>Window's mpm_winnt interprets the AcceptFilter to toggle the AcceptEx()
194 API, and does not support http protocol buffering. There are two values
195 which utilize the Windows AcceptEx() API and will recycle network
196 sockets between connections. <code>data</code> waits until data has
197 been transmitted as documented above, and the initial data buffer and
198 network endpoint addresses are all retrieved from the single AcceptEx()
199 invocation. <code>connect</code> will use the AcceptEx() API, also
200 retrieve the network endpoint addresses, but like <code>none</code>
201 the <code>connect</code> option does not wait for the initial data
204 <p>On Windows, <code>none</code> uses accept() rather than AcceptEx()
205 and will not recycle sockets between connections. This is useful for
206 network adapters with broken driver support, as well as some virtual
207 network providers such as vpn drivers, or spam, virus or spyware
213 <li><code class="directive"><a href="#protocol">Protocol</a></code></li>
216 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
217 <div class="directive-section"><h2><a name="AcceptPathInfo" id="AcceptPathInfo">AcceptPathInfo</a> <a name="acceptpathinfo" id="acceptpathinfo">Directive</a></h2>
218 <table class="directive">
219 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Resources accept trailing pathname information</td></tr>
220 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptPathInfo On|Off|Default</code></td></tr>
221 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AcceptPathInfo Default</code></td></tr>
222 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
223 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
224 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
225 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
228 <p>This directive controls whether requests that contain trailing
229 pathname information that follows an actual filename (or
230 non-existent file in an existing directory) will be accepted or
231 rejected. The trailing pathname information can be made
232 available to scripts in the <code>PATH_INFO</code> environment
235 <p>For example, assume the location <code>/test/</code> points to
236 a directory that contains only the single file
237 <code>here.html</code>. Then requests for
238 <code>/test/here.html/more</code> and
239 <code>/test/nothere.html/more</code> both collect
240 <code>/more</code> as <code>PATH_INFO</code>.</p>
242 <p>The three possible arguments for the
243 <code class="directive">AcceptPathInfo</code> directive are:</p>
245 <dt><code>Off</code></dt><dd>A request will only be accepted if it
246 maps to a literal path that exists. Therefore a request with
247 trailing pathname information after the true filename such as
248 <code>/test/here.html/more</code> in the above example will return
249 a 404 NOT FOUND error.</dd>
251 <dt><code>On</code></dt><dd>A request will be accepted if a
252 leading path component maps to a file that exists. The above
253 example <code>/test/here.html/more</code> will be accepted if
254 <code>/test/here.html</code> maps to a valid file.</dd>
256 <dt><code>Default</code></dt><dd>The treatment of requests with
257 trailing pathname information is determined by the <a href="../handler.html">handler</a> responsible for the request.
258 The core handler for normal files defaults to rejecting
259 <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
260 <code>PATH_INFO</code> by default.</dd>
263 <p>The primary purpose of the <code>AcceptPathInfo</code>
264 directive is to allow you to override the handler's choice of
265 accepting or rejecting <code>PATH_INFO</code>. This override is required,
266 for example, when you use a <a href="../filter.html">filter</a>, such
267 as <a href="mod_include.html">INCLUDES</a>, to generate content
268 based on <code>PATH_INFO</code>. The core handler would usually reject
269 the request, so you can use the following configuration to enable
272 <pre class="prettyprint lang-config">
273 <Files "mypaths.shtml">
275 SetOutputFilter INCLUDES
283 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
284 <div class="directive-section"><h2><a name="AccessFileName" id="AccessFileName">AccessFileName</a> <a name="accessfilename" id="accessfilename">Directive</a></h2>
285 <table class="directive">
286 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Name of the distributed configuration file</td></tr>
287 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AccessFileName <var>filename</var> [<var>filename</var>] ...</code></td></tr>
288 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AccessFileName .htaccess</code></td></tr>
289 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
290 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
291 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
293 <p>While processing a request the server looks for
294 the first existing configuration file from this list of names in
295 every directory of the path to the document, if distributed
296 configuration files are <a href="#allowoverride">enabled for that
297 directory</a>. For example:</p>
299 <pre class="prettyprint lang-config">AccessFileName .acl</pre>
302 <p>before returning the document
303 <code>/usr/local/web/index.html</code>, the server will read
304 <code>/.acl</code>, <code>/usr/.acl</code>,
305 <code>/usr/local/.acl</code> and <code>/usr/local/web/.acl</code>
306 for directives, unless they have been disabled with</p>
308 <pre class="prettyprint lang-config">
317 <li><code class="directive"><a href="#allowoverride">AllowOverride</a></code></li>
318 <li><a href="../configuring.html">Configuration Files</a></li>
319 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
322 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
323 <div class="directive-section"><h2><a name="AddDefaultCharset" id="AddDefaultCharset">AddDefaultCharset</a> <a name="adddefaultcharset" id="adddefaultcharset">Directive</a></h2>
324 <table class="directive">
325 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Default charset parameter to be added when a response
326 content-type is <code>text/plain</code> or <code>text/html</code></td></tr>
327 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AddDefaultCharset On|Off|<var>charset</var></code></td></tr>
328 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AddDefaultCharset Off</code></td></tr>
329 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
330 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
331 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
332 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
334 <p>This directive specifies a default value for the media type
335 charset parameter (the name of a character encoding) to be added
336 to a response if and only if the response's content-type is either
337 <code>text/plain</code> or <code>text/html</code>. This should override
338 any charset specified in the body of the response via a <code>META</code>
339 element, though the exact behavior is often dependent on the user's client
340 configuration. A setting of <code>AddDefaultCharset Off</code>
341 disables this functionality. <code>AddDefaultCharset On</code> enables
342 a default charset of <code>iso-8859-1</code>. Any other value is assumed
343 to be the <var>charset</var> to be used, which should be one of the
344 <a href="http://www.iana.org/assignments/character-sets">IANA registered
345 charset values</a> for use in Internet media types (MIME types).
348 <pre class="prettyprint lang-config">AddDefaultCharset utf-8</pre>
351 <p><code class="directive">AddDefaultCharset</code> should only be used when all
352 of the text resources to which it applies are known to be in that
353 character encoding and it is too inconvenient to label their charset
354 individually. One such example is to add the charset parameter
355 to resources containing generated content, such as legacy CGI
356 scripts, that might be vulnerable to cross-site scripting attacks
357 due to user-provided data being included in the output. Note, however,
358 that a better solution is to just fix (or delete) those scripts, since
359 setting a default charset does not protect users that have enabled
360 the "auto-detect character encoding" feature on their browser.</p>
364 <li><code class="directive"><a href="../mod/mod_mime.html#addcharset">AddCharset</a></code></li>
367 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
368 <div class="directive-section"><h2><a name="AllowEncodedSlashes" id="AllowEncodedSlashes">AllowEncodedSlashes</a> <a name="allowencodedslashes" id="allowencodedslashes">Directive</a></h2>
369 <table class="directive">
370 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines whether encoded path separators in URLs are allowed to
371 be passed through</td></tr>
372 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowEncodedSlashes On|Off|NoDecode</code></td></tr>
373 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowEncodedSlashes Off</code></td></tr>
374 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
375 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
376 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
377 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>
378 NoDecode option available in 2.3.12 and later.</td></tr>
380 <p>The <code class="directive">AllowEncodedSlashes</code> directive allows URLs
381 which contain encoded path separators (<code>%2F</code> for <code>/</code>
382 and additionally <code>%5C</code> for <code>\</code> on according systems)
383 to be used in the path info.</p>
385 <p>With the default value, <code>Off</code>, such URLs are refused
386 with a 404 (Not found) error.</p>
388 <p>With the value <code>On</code>, such URLs are accepted, and encoded
389 slashes are decoded like all other encoded characters.</p>
391 <p>With the value <code>NoDecode</code>, such URLs are accepted, but
392 encoded slashes are not decoded but left in their encoded state.</p>
394 <p>Turning <code class="directive">AllowEncodedSlashes</code> <code>On</code> is
395 mostly useful when used in conjunction with <code>PATH_INFO</code>.</p>
397 <div class="note"><h3>Note</h3>
398 <p>If encoded slashes are needed in path info, use of <code>NoDecode</code> is
399 strongly recommended as a security measure. Allowing slashes
400 to be decoded could potentially allow unsafe paths.</p>
405 <li><code class="directive"><a href="#acceptpathinfo">AcceptPathInfo</a></code></li>
408 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
409 <div class="directive-section"><h2><a name="AllowOverride" id="AllowOverride">AllowOverride</a> <a name="allowoverride" id="allowoverride">Directive</a></h2>
410 <table class="directive">
411 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Types of directives that are allowed in
412 <code>.htaccess</code> files</td></tr>
413 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowOverride All|None|<var>directive-type</var>
414 [<var>directive-type</var>] ...</code></td></tr>
415 <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>
416 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
417 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
418 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
420 <p>When the server finds an <code>.htaccess</code> file (as
421 specified by <code class="directive"><a href="#accessfilename">AccessFileName</a></code>)
422 it needs to know which directives declared in that file can override
423 earlier configuration directives.</p>
425 <div class="note"><h3>Only available in <Directory> sections</h3>
426 <code class="directive">AllowOverride</code> is valid only in
427 <code class="directive"><a href="#directory"><Directory></a></code>
428 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
429 <code class="directive"><a href="#files"><Files></a></code> sections.
432 <p>When this directive is set to <code>None</code> and <code class="directive"><a href="#allowoverridelist">AllowOverrideList</a></code> is set to
433 <code>None</code> <a href="#accessfilename">.htaccess</a> files are
434 completely ignored. In this case, the server will not even attempt
435 to read <code>.htaccess</code> files in the filesystem.</p>
437 <p>When this directive is set to <code>All</code>, then any
438 directive which has the .htaccess <a href="directive-dict.html#Context">Context</a> is allowed in
439 <code>.htaccess</code> files.</p>
441 <p>The <var>directive-type</var> can be one of the following
442 groupings of directives.</p>
449 Allow use of the authorization directives (<code class="directive"><a href="../mod/mod_authz_dbm.html#authdbmgroupfile">AuthDBMGroupFile</a></code>,
450 <code class="directive"><a href="../mod/mod_authn_dbm.html#authdbmuserfile">AuthDBMUserFile</a></code>,
451 <code class="directive"><a href="../mod/mod_authz_groupfile.html#authgroupfile">AuthGroupFile</a></code>,
452 <code class="directive"><a href="../mod/mod_authn_core.html#authname">AuthName</a></code>,
453 <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>
458 Allow use of the directives controlling document types
459 (<code class="directive"><a href="#errordocument">ErrorDocument</a></code>,
460 <code class="directive"><a href="#forcetype">ForceType</a></code>,
461 <code class="directive"><a href="../mod/mod_negotiation.html#languagepriority">LanguagePriority</a></code>,
462 <code class="directive"><a href="#sethandler">SetHandler</a></code>,
463 <code class="directive"><a href="#setinputfilter">SetInputFilter</a></code>,
464 <code class="directive"><a href="#setoutputfilter">SetOutputFilter</a></code>, and
465 <code class="module"><a href="../mod/mod_mime.html">mod_mime</a></code> Add* and Remove* directives),
466 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>),
467 <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>),
468 <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
469 <code class="directive"><a href="../mod/mod_actions.html#action">Action</a></code> from
470 <code class="module"><a href="../mod/mod_actions.html">mod_actions</a></code>.
476 Allow use of the directives controlling directory indexing
477 (<code class="directive"><a href="../mod/mod_autoindex.html#adddescription">AddDescription</a></code>,
478 <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>,
479 <code class="directive"><a href="../mod/mod_autoindex.html#addiconbytype">AddIconByType</a></code>,
480 <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>,
486 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>
491 <dt>Nonfatal=[Override|Unknown|All]</dt>
494 Allow use of AllowOverride option to treat syntax errors in
495 .htaccess as non-fatal: instead of causing an Internal Server
496 Error, disallowed or unrecognised directives will be ignored
497 and a warning logged:
499 <li><strong>Nonfatal=Override</strong> treats directives
500 forbidden by AllowOverride as non-fatal.</li>
501 <li><strong>Nonfatal=Unknown</strong> treats unknown directives
502 as non-fatal. This covers typos and directives implemented
503 by a module that's not present.</li>
504 <li><strong>Nonfatal=All</strong> treats both the above as non-fatal.</li>
506 <p>Note that a syntax error in a valid directive will still cause
507 an internal server error.</p>
508 <div class="warning"><h3>Security</h3>
509 Nonfatal errors may have security implications for .htaccess users.
510 For example, if AllowOverride disallows AuthConfig, users'
511 configuration designed to restrict access to a site will be disabled.
515 <dt>Options[=<var>Option</var>,...]</dt>
518 Allow use of the directives controlling specific directory
519 features (<code class="directive"><a href="#options">Options</a></code> and
520 <code class="directive"><a href="../mod/mod_include.html#xbithack">XBitHack</a></code>).
521 An equal sign may be given followed by a comma (but no spaces)
522 separated lists of options that may be set using the <code class="directive"><a href="#options">Options</a></code> command.
524 <div class="note"><h3>Implicit disabling of Options</h3>
525 <p>Even though the list of options that may be used in .htaccess files
526 can be limited with this directive, as long as any <code class="directive"><a href="#options">Options</a></code> directive is allowed any
527 other inherited option can be disabled by using the non-relative
528 syntax. In other words, this mechanism cannot force a specific option
529 to remain <em>set</em> while allowing any others to be set.
532 <div class="example"><p><code>
533 AllowOverride Options=Indexes,MultiViews
540 <pre class="prettyprint lang-config">AllowOverride AuthConfig Indexes</pre>
543 <p>In the example above all directives that are neither in the group
544 <code>AuthConfig</code> nor <code>Indexes</code> cause an internal
547 <div class="note"><p>For security and performance reasons, do not set
548 <code>AllowOverride</code> to anything other than <code>None</code>
549 in your <code><Directory /></code> block. Instead, find (or
550 create) the <code><Directory></code> block that refers to the
551 directory where you're actually planning to place a
552 <code>.htaccess</code> file.</p>
557 <li><code class="directive"><a href="#accessfilename">AccessFileName</a></code></li>
558 <li><code class="directive"><a href="#allowoverridelist">AllowOverrideList</a></code></li>
559 <li><a href="../configuring.html">Configuration Files</a></li>
560 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
563 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
564 <div class="directive-section"><h2><a name="AllowOverrideList" id="AllowOverrideList">AllowOverrideList</a> <a name="allowoverridelist" id="allowoverridelist">Directive</a></h2>
565 <table class="directive">
566 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Individual directives that are allowed in
567 <code>.htaccess</code> files</td></tr>
568 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowOverrideList None|<var>directive</var>
569 [<var>directive-type</var>] ...</code></td></tr>
570 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowOverrideList None</code></td></tr>
571 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
572 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
573 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
575 <p>When the server finds an <code>.htaccess</code> file (as
576 specified by <code class="directive"><a href="#accessfilename">AccessFileName</a></code>)
577 it needs to know which directives declared in that file can override
578 earlier configuration directives.</p>
580 <div class="note"><h3>Only available in <Directory> sections</h3>
581 <code class="directive">AllowOverrideList</code> is valid only in
582 <code class="directive"><a href="#directory"><Directory></a></code>
583 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
584 <code class="directive"><a href="#files"><Files></a></code> sections.
587 <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>,
588 then <a href="#accessfilename">.htaccess</a> files are completely
589 ignored. In this case, the server will not even attempt to read
590 <code>.htaccess</code> files in the filesystem.</p>
594 <pre class="prettyprint lang-config">
596 AllowOverrideList Redirect RedirectMatch
600 <p>In the example above only the <code>Redirect</code> and
601 <code>RedirectMatch</code> directives are allowed. All others will
602 cause an internal server error.</p>
606 <pre class="prettyprint lang-config">
607 AllowOverride AuthConfig
608 AllowOverrideList CookieTracking CookieName
612 <p>In the example above <code class="directive"><a href="#allowoverride ">AllowOverride
613 </a></code> grants permission to the <code>AuthConfig</code>
614 directive grouping and <code class="directive">AllowOverrideList</code> grants
615 permission to only two directives from the <code>FileInfo</code> directive
616 grouping. All others will cause an internal server error.</p>
620 <li><code class="directive"><a href="#accessfilename">AccessFileName</a></code></li>
621 <li><code class="directive"><a href="#allowoverride">AllowOverride</a></code></li>
622 <li><a href="../configuring.html">Configuration Files</a></li>
623 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
626 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
627 <div class="directive-section"><h2><a name="CGIMapExtension" id="CGIMapExtension">CGIMapExtension</a> <a name="cgimapextension" id="cgimapextension">Directive</a></h2>
628 <table class="directive">
629 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
631 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CGIMapExtension <var>cgi-path</var> <var>.extension</var></code></td></tr>
632 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
633 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
634 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
635 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
636 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>NetWare only</td></tr>
638 <p>This directive is used to control how Apache httpd finds the
639 interpreter used to run CGI scripts. For example, setting
640 <code>CGIMapExtension sys:\foo.nlm .foo</code> will
641 cause all CGI script files with a <code>.foo</code> extension to
642 be passed to the FOO interpreter.</p>
645 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
646 <div class="directive-section"><h2><a name="ContentDigest" id="ContentDigest">ContentDigest</a> <a name="contentdigest" id="contentdigest">Directive</a></h2>
647 <table class="directive">
648 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables the generation of <code>Content-MD5</code> HTTP Response
650 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ContentDigest On|Off</code></td></tr>
651 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ContentDigest Off</code></td></tr>
652 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
653 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
654 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
655 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
657 <p>This directive enables the generation of
658 <code>Content-MD5</code> headers as defined in RFC1864
659 respectively RFC2616.</p>
661 <p>MD5 is an algorithm for computing a "message digest"
662 (sometimes called "fingerprint") of arbitrary-length data, with
663 a high degree of confidence that any alterations in the data
664 will be reflected in alterations in the message digest.</p>
666 <p>The <code>Content-MD5</code> header provides an end-to-end
667 message integrity check (MIC) of the entity-body. A proxy or
668 client may check this header for detecting accidental
669 modification of the entity-body in transit. Example header:</p>
671 <div class="example"><p><code>
672 Content-MD5: AuLb7Dp1rqtRtxz2m9kRpA==
675 <p>Note that this can cause performance problems on your server
676 since the message digest is computed on every request (the
677 values are not cached).</p>
679 <p><code>Content-MD5</code> is only sent for documents served
680 by the <code class="module"><a href="../mod/core.html">core</a></code>, and not by any module. For example,
681 SSI documents, output from CGI scripts, and byte range responses
682 do not have this header.</p>
685 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
686 <div class="directive-section"><h2><a name="DefaultRuntimeDir" id="DefaultRuntimeDir">DefaultRuntimeDir</a> <a name="defaultruntimedir" id="defaultruntimedir">Directive</a></h2>
687 <table class="directive">
688 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server run-time files</td></tr>
689 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultRuntimeDir <var>directory-path</var></code></td></tr>
690 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultRuntimeDir DEFAULT_REL_RUNTIMEDIR (logs/)</code></td></tr>
691 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
692 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
693 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
695 <p>The <code class="directive">DefaultRuntimeDir</code> directive sets the
696 directory in which the server will create various run-time files
697 (shared memory, locks, etc.). If set as a relative path, the full path
698 will be relative to <code class="directive">ServerRoot</code>.</p>
700 <p><strong>Example</strong></p>
701 <pre class="prettyprint lang-config">
702 DefaultRuntimeDir scratch/
706 <p>The default location of <code class="directive">DefaultRuntimeDir</code> may be
707 modified by changing the <code>DEFAULT_REL_RUNTIMEDIR</code> #define
710 <p>Note: <code class="directive">ServerRoot</code> should be specified before this
711 directive is used, otherwise the default value of <code class="directive">ServerRoot</code>
712 would be used to set the base directory.</p>
717 <li><a href="../misc/security_tips.html#serverroot">the
718 security tips</a> for information on how to properly set
719 permissions on the <code class="directive">ServerRoot</code></li>
722 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
723 <div class="directive-section"><h2><a name="DefaultType" id="DefaultType">DefaultType</a> <a name="defaulttype" id="defaulttype">Directive</a></h2>
724 <table class="directive">
725 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>This directive has no effect other than to emit warnings
726 if the value is not <code>none</code>. In prior versions, DefaultType
727 would specify a default media type to assign to response content for
728 which no other media type configuration could be found.
730 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultType <var>media-type|none</var></code></td></tr>
731 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultType none</code></td></tr>
732 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
733 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
734 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
735 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
736 <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.
739 <p>This directive has been disabled. For backwards compatibility
740 of configuration files, it may be specified with the value
741 <code>none</code>, meaning no default media type. For example:</p>
743 <pre class="prettyprint lang-config">DefaultType None</pre>
746 <p><code>DefaultType None</code> is only available in
747 httpd-2.2.7 and later.</p>
749 <p>Use the mime.types configuration file and the
750 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code> to configure media
751 type assignments via file extensions, or the
752 <code class="directive"><a href="#forcetype">ForceType</a></code> directive to configure
753 the media type for specific resources. Otherwise, the server will
754 send the response without a Content-Type header field and the
755 recipient may attempt to guess the media type.</p>
758 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
759 <div class="directive-section"><h2><a name="Define" id="Define">Define</a> <a name="define" id="define">Directive</a></h2>
760 <table class="directive">
761 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Define a variable</td></tr>
762 <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>
763 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
764 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
765 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
767 <p>In its one parameter form, <code class="directive">Define</code> is equivalent
768 to passing the <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>. It
769 can be used to toggle the use of
770 <code class="directive"><a href="#ifdefine"><IfDefine></a></code> sections
771 without needing to alter <code>-D</code> arguments in any startup
774 <p>In addition to that, if the second parameter is given, a config variable
775 is set to this value. The variable can be used in the configuration using
776 the <code>${VAR}</code> syntax. The variable is always globally defined
777 and not limited to the scope of the surrounding config section.</p>
779 <pre class="prettyprint lang-config">
780 <IfDefine TEST>
781 Define servername test.example.com
783 <IfDefine !TEST>
784 Define servername www.example.com
788 DocumentRoot /var/www/${servername}/htdocs
792 <p>Variable names may not contain colon ":" characters, to avoid clashes
793 with <code class="directive"><a href="../mod/mod_rewrite.html#rewritemap">RewriteMap</a></code>'s syntax.</p>
796 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
797 <div class="directive-section"><h2><a name="Directory" id="Directory"><Directory></a> <a name="directory" id="directory">Directive</a></h2>
798 <table class="directive">
799 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose a group of directives that apply only to the
800 named file-system directory, sub-directories, and their contents.</td></tr>
801 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Directory <var>directory-path</var>>
802 ... </Directory></code></td></tr>
803 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
804 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
805 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
807 <p><code class="directive"><Directory></code> and
808 <code></Directory></code> are used to enclose a group of
809 directives that will apply only to the named directory,
810 sub-directories of that directory, and the files within the respective
811 directories. Any directive that is allowed
812 in a directory context may be used. <var>Directory-path</var> is
813 either the full path to a directory, or a wild-card string using
814 Unix shell-style matching. In a wild-card string, <code>?</code> matches
815 any single character, and <code>*</code> matches any sequences of
816 characters. You may also use <code>[]</code> character ranges. None
817 of the wildcards match a `/' character, so <code><Directory
818 /*/public_html></code> will not match
819 <code>/home/user/public_html</code>, but <code><Directory
820 /home/*/public_html></code> will match. Example:</p>
822 <pre class="prettyprint lang-config">
823 <Directory "/usr/local/httpd/htdocs">
824 Options Indexes FollowSymLinks
830 <p>Be careful with the <var>directory-path</var> arguments:
831 They have to literally match the filesystem path which Apache httpd uses
832 to access the files. Directives applied to a particular
833 <code><Directory></code> will not apply to files accessed from
834 that same directory via a different path, such as via different symbolic
838 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular
839 expressions</a> can also be used, with the addition of the
840 <code>~</code> character. For example:</p>
842 <pre class="prettyprint lang-config">
843 <Directory ~ "^/www/[0-9]{3}">
849 <p>would match directories in <code>/www/</code> that consisted of
852 <p>If multiple (non-regular expression) <code class="directive"><Directory></code> sections
853 match the directory (or one of its parents) containing a document,
854 then the directives are applied in the order of shortest match
855 first, interspersed with the directives from the <a href="#accessfilename">.htaccess</a> files. For example,
858 <pre class="prettyprint lang-config">
863 <Directory "/home">
864 AllowOverride FileInfo
869 <p>for access to the document <code>/home/web/dir/doc.html</code>
873 <li>Apply directive <code>AllowOverride None</code>
874 (disabling <code>.htaccess</code> files).</li>
876 <li>Apply directive <code>AllowOverride FileInfo</code> (for
877 directory <code>/home</code>).</li>
879 <li>Apply any <code>FileInfo</code> directives in
880 <code>/home/.htaccess</code>, <code>/home/web/.htaccess</code> and
881 <code>/home/web/dir/.htaccess</code> in that order.</li>
884 <p>Regular expressions are not considered until after all of the
885 normal sections have been applied. Then all of the regular
886 expressions are tested in the order they appeared in the
887 configuration file. For example, with</p>
889 <pre class="prettyprint lang-config">
890 <Directory ~ "abc$">
891 # ... directives here ...
896 <p>the regular expression section won't be considered until after
897 all normal <code class="directive"><Directory></code>s and
898 <code>.htaccess</code> files have been applied. Then the regular
899 expression will match on <code>/home/abc/public_html/abc</code> and
900 the corresponding <code class="directive"><Directory></code> will
903 <p><strong>Note that the default access for
904 <code><Directory /></code> is to permit all access.
905 This means that Apache httpd will serve any file mapped from an URL. It is
906 recommended that you change this with a block such
909 <pre class="prettyprint lang-config">
916 <p><strong>and then override this for directories you
917 <em>want</em> accessible. See the <a href="../misc/security_tips.html">Security Tips</a> page for more
918 details.</strong></p>
920 <p>The directory sections occur in the <code>httpd.conf</code> file.
921 <code class="directive"><Directory></code> directives
922 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>
926 <li><a href="../sections.html">How <Directory>,
927 <Location> and <Files> sections work</a> for an
928 explanation of how these different sections are combined when a
929 request is received</li>
932 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
933 <div class="directive-section"><h2><a name="DirectoryMatch" id="DirectoryMatch"><DirectoryMatch></a> <a name="directorymatch" id="directorymatch">Directive</a></h2>
934 <table class="directive">
935 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose directives that apply to
936 the contents of file-system directories matching a regular expression.</td></tr>
937 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><DirectoryMatch <var>regex</var>>
938 ... </DirectoryMatch></code></td></tr>
939 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
940 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
941 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
943 <p><code class="directive"><DirectoryMatch></code> and
944 <code></DirectoryMatch></code> are used to enclose a group
945 of directives which will apply only to the named directory (and the files within),
946 the same as <code class="directive"><a href="#directory"><Directory></a></code>.
947 However, it takes as an argument a
948 <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>. For example:</p>
950 <pre class="prettyprint lang-config">
951 <DirectoryMatch "^/www/(.+/)?[0-9]{3}">
953 </DirectoryMatch>
957 <p>would match directories in <code>/www/</code> that consisted of three
960 <div class="note"><h3>Compatability</h3>
961 Prior to 2.3.9, this directive implicitly applied to sub-directories
962 (like <code class="directive"><a href="#directory"><Directory></a></code>) and
963 could not match the end of line symbol ($). In 2.3.9 and later,
964 only directories that match the expression are affected by the enclosed
968 <div class="note"><h3>Trailing Slash</h3>
969 This directive applies to requests for directories that may or may
970 not end in a trailing slash, so expressions that are anchored to the
971 end of line ($) must be written with care.
974 <p>From 2.4.8 onwards, named groups and backreferences are captured and
975 written to the environment with the corresponding name prefixed with
976 "MATCH_" and in upper case. This allows elements of paths to be referenced
977 from within <a href="expr.html">expressions</a> and modules like
978 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
979 (unnamed) backreferences are ignored. Use named groups instead.</p>
981 <pre class="prettyprint lang-config">
982 <DirectoryMatch ^/var/www/combined/(?<sitename>[^/]+)>
983 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
984 </DirectoryMatch>
990 <li><code class="directive"><a href="#directory"><Directory></a></code> for
991 a description of how regular expressions are mixed in with normal
992 <code class="directive"><Directory></code>s</li>
993 <li><a href="../sections.html">How <Directory>, <Location> and
994 <Files> sections work</a> for an explanation of how these different
995 sections are combined when a request is received</li>
998 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
999 <div class="directive-section"><h2><a name="DocumentRoot" id="DocumentRoot">DocumentRoot</a> <a name="documentroot" id="documentroot">Directive</a></h2>
1000 <table class="directive">
1001 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory that forms the main document tree visible
1002 from the web</td></tr>
1003 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DocumentRoot <var>directory-path</var></code></td></tr>
1004 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DocumentRoot /usr/local/apache/htdocs</code></td></tr>
1005 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1006 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1007 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1009 <p>This directive sets the directory from which <code class="program"><a href="../programs/httpd.html">httpd</a></code>
1010 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
1011 path from the requested URL to the document root to make the
1012 path to the document. Example:</p>
1014 <pre class="prettyprint lang-config">DocumentRoot "/usr/web"</pre>
1017 <p>then an access to
1018 <code>http://my.example.com/index.html</code> refers to
1019 <code>/usr/web/index.html</code>. If the <var>directory-path</var> is
1020 not absolute then it is assumed to be relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1022 <p>The <code class="directive">DocumentRoot</code> should be specified without
1023 a trailing slash.</p>
1027 <li><a href="../urlmapping.html#documentroot">Mapping URLs to Filesystem
1031 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1032 <div class="directive-section"><h2><a name="Else" id="Else"><Else></a> <a name="else" id="else">Directive</a></h2>
1033 <table class="directive">
1034 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if the condition of a
1035 previous <code class="directive"><a href="#if"><If></a></code> or
1036 <code class="directive"><a href="#elseif"><ElseIf></a></code> section is not
1037 satisfied by a request at runtime</td></tr>
1038 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Else> ... </Else></code></td></tr>
1039 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1040 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1041 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1042 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1044 <p>The <code class="directive"><Else></code> applies the enclosed
1045 directives if and only if the most recent
1046 <code class="directive"><If></code> or
1047 <code class="directive"><ElseIf></code> section
1048 in the same scope has not been applied.
1049 For example: In </p>
1051 <pre class="prettyprint lang-config">
1052 <If "-z req('Host')">
1061 <p> The <code class="directive"><If></code> would match HTTP/1.0
1062 requests without a <var>Host:</var> header and the
1063 <code class="directive"><Else></code> would match requests
1064 with a <var>Host:</var> header.</p>
1069 <li><code class="directive"><a href="#if"><If></a></code></li>
1070 <li><code class="directive"><a href="#elseif"><ElseIf></a></code></li>
1071 <li><a href="../sections.html">How <Directory>, <Location>,
1072 <Files> sections work</a> for an explanation of how these
1073 different sections are combined when a request is received.
1074 <code class="directive"><If></code>,
1075 <code class="directive"><ElseIf></code>, and
1076 <code class="directive"><Else></code> are applied last.</li>
1079 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1080 <div class="directive-section"><h2><a name="ElseIf" id="ElseIf"><ElseIf></a> <a name="elseif" id="elseif">Directive</a></h2>
1081 <table class="directive">
1082 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is satisfied
1083 by a request at runtime while the condition of a previous
1084 <code class="directive"><a href="#if"><If></a></code> or
1085 <code class="directive"><ElseIf></code> section is not
1087 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><ElseIf <var>expression</var>> ... </ElseIf></code></td></tr>
1088 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1089 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1090 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1091 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1093 <p>The <code class="directive"><ElseIf></code> applies the enclosed
1094 directives if and only if both the given condition evaluates to true and
1095 the most recent <code class="directive"><If></code> or
1096 <code class="directive"><ElseIf></code> section in the same scope has
1097 not been applied. For example: In </p>
1099 <pre class="prettyprint lang-config">
1100 <If "-R '10.1.0.0/16'">
1103 <ElseIf "-R '10.0.0.0/8'">
1112 <p>The <code class="directive"><ElseIf></code> would match if
1113 the remote address of a request belongs to the subnet 10.0.0.0/8 but
1114 not to the subnet 10.1.0.0/16.</p>
1119 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
1120 for a complete reference and more examples.</li>
1121 <li><code class="directive"><a href="#if"><If></a></code></li>
1122 <li><code class="directive"><a href="#else"><Else></a></code></li>
1123 <li><a href="../sections.html">How <Directory>, <Location>,
1124 <Files> sections work</a> for an explanation of how these
1125 different sections are combined when a request is received.
1126 <code class="directive"><If></code>,
1127 <code class="directive"><ElseIf></code>, and
1128 <code class="directive"><Else></code> are applied last.</li>
1131 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1132 <div class="directive-section"><h2><a name="EnableMMAP" id="EnableMMAP">EnableMMAP</a> <a name="enablemmap" id="enablemmap">Directive</a></h2>
1133 <table class="directive">
1134 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use memory-mapping to read files during delivery</td></tr>
1135 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableMMAP On|Off</code></td></tr>
1136 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableMMAP On</code></td></tr>
1137 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1138 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1139 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1140 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1142 <p>This directive controls whether the <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use
1143 memory-mapping if it needs to read the contents of a file during
1144 delivery. By default, when the handling of a request requires
1145 access to the data within a file -- for example, when delivering a
1146 server-parsed file using <code class="module"><a href="../mod/mod_include.html">mod_include</a></code> -- Apache httpd
1147 memory-maps the file if the OS supports it.</p>
1149 <p>This memory-mapping sometimes yields a performance improvement.
1150 But in some environments, it is better to disable the memory-mapping
1151 to prevent operational problems:</p>
1154 <li>On some multiprocessor systems, memory-mapping can reduce the
1155 performance of the <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</li>
1156 <li>Deleting or truncating a file while <code class="program"><a href="../programs/httpd.html">httpd</a></code>
1157 has it memory-mapped can cause <code class="program"><a href="../programs/httpd.html">httpd</a></code> to
1158 crash with a segmentation fault.
1162 <p>For server configurations that are vulnerable to these problems,
1163 you should disable memory-mapping of delivered files by specifying:</p>
1165 <pre class="prettyprint lang-config">EnableMMAP Off</pre>
1168 <p>For NFS mounted files, this feature may be disabled explicitly for
1169 the offending files by specifying:</p>
1171 <pre class="prettyprint lang-config">
1172 <Directory "/path-to-nfs-files">
1179 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1180 <div class="directive-section"><h2><a name="EnableSendfile" id="EnableSendfile">EnableSendfile</a> <a name="enablesendfile" id="enablesendfile">Directive</a></h2>
1181 <table class="directive">
1182 <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>
1183 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableSendfile On|Off</code></td></tr>
1184 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableSendfile Off</code></td></tr>
1185 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1186 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1187 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1188 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1189 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Default changed to Off in
1190 version 2.3.9.</td></tr>
1192 <p>This directive controls whether <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use the
1193 sendfile support from the kernel to transmit file contents to the client.
1194 By default, when the handling of a request requires no access
1195 to the data within a file -- for example, when delivering a
1196 static file -- Apache httpd uses sendfile to deliver the file contents
1197 without ever reading the file if the OS supports it.</p>
1199 <p>This sendfile mechanism avoids separate read and send operations,
1200 and buffer allocations. But on some platforms or within some
1201 filesystems, it is better to disable this feature to avoid
1202 operational problems:</p>
1205 <li>Some platforms may have broken sendfile support that the build
1206 system did not detect, especially if the binaries were built on
1207 another box and moved to such a machine with broken sendfile
1209 <li>On Linux the use of sendfile triggers TCP-checksum
1210 offloading bugs on certain networking cards when using IPv6.</li>
1211 <li>On Linux on Itanium, <code>sendfile</code> may be unable to handle
1212 files over 2GB in size.</li>
1213 <li>With a network-mounted <code class="directive"><a href="#documentroot">DocumentRoot</a></code> (e.g., NFS, SMB, CIFS, FUSE),
1214 the kernel may be unable to serve the network file through
1218 <p>For server configurations that are not vulnerable to these problems,
1219 you may enable this feature by specifying:</p>
1221 <pre class="prettyprint lang-config">EnableSendfile On</pre>
1224 <p>For network mounted files, this feature may be disabled explicitly
1225 for the offending files by specifying:</p>
1227 <pre class="prettyprint lang-config">
1228 <Directory "/path-to-nfs-files">
1233 <p>Please note that the per-directory and .htaccess configuration
1234 of <code class="directive">EnableSendfile</code> is not supported by
1235 <code class="module"><a href="../mod/mod_cache_disk.html">mod_cache_disk</a></code>.
1236 Only global definition of <code class="directive">EnableSendfile</code>
1237 is taken into account by the module.
1241 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1242 <div class="directive-section"><h2><a name="Error" id="Error">Error</a> <a name="error" id="error">Directive</a></h2>
1243 <table class="directive">
1244 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Abort configuration parsing with a custom error message</td></tr>
1245 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Error <var>message</var></code></td></tr>
1246 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1247 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1248 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1249 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.3.9 and later</td></tr>
1251 <p>If an error can be detected within the configuration, this
1252 directive can be used to generate a custom error message, and halt
1253 configuration parsing. The typical use is for reporting required
1254 modules which are missing from the configuration.</p>
1256 <pre class="prettyprint lang-config">
1258 # ensure that mod_include is loaded
1259 <IfModule !include_module>
1260 Error "mod_include is required by mod_foo. Load it with LoadModule."
1263 # ensure that exactly one of SSL,NOSSL is defined
1264 <IfDefine SSL>
1265 <IfDefine NOSSL>
1266 Error "Both SSL and NOSSL are defined. Define only one of them."
1269 <IfDefine !SSL>
1270 <IfDefine !NOSSL>
1271 Error "Either SSL or NOSSL must be defined."
1279 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1280 <div class="directive-section"><h2><a name="ErrorDocument" id="ErrorDocument">ErrorDocument</a> <a name="errordocument" id="errordocument">Directive</a></h2>
1281 <table class="directive">
1282 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>What the server will return to the client
1283 in case of an error</td></tr>
1284 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ErrorDocument <var>error-code</var> <var>document</var></code></td></tr>
1285 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1286 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1287 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1288 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1290 <p>In the event of a problem or error, Apache httpd can be configured
1291 to do one of four things,</p>
1294 <li>output a simple hardcoded error message</li>
1296 <li>output a customized message</li>
1298 <li>internally redirect to a local <var>URL-path</var> to handle the
1301 <li>redirect to an external <var>URL</var> to handle the
1305 <p>The first option is the default, while options 2-4 are
1306 configured using the <code class="directive">ErrorDocument</code>
1307 directive, which is followed by the HTTP response code and a URL
1308 or a message. Apache httpd will sometimes offer additional information
1309 regarding the problem/error.</p>
1311 <p>URLs can begin with a slash (/) for local web-paths (relative
1312 to the <code class="directive"><a href="#documentroot">DocumentRoot</a></code>), or be a
1313 full URL which the client can resolve. Alternatively, a message
1314 can be provided to be displayed by the browser. Examples:</p>
1316 <pre class="prettyprint lang-config">
1317 ErrorDocument 500 http://foo.example.com/cgi-bin/tester
1318 ErrorDocument 404 /cgi-bin/bad_urls.pl
1319 ErrorDocument 401 /subscription_info.html
1320 ErrorDocument 403 "Sorry can't allow you access today"
1321 ErrorDocument 403 Forbidden!
1325 <p>Additionally, the special value <code>default</code> can be used
1326 to specify Apache httpd's simple hardcoded message. While not required
1327 under normal circumstances, <code>default</code> will restore
1328 Apache httpd's simple hardcoded message for configurations that would
1329 otherwise inherit an existing <code class="directive">ErrorDocument</code>.</p>
1331 <pre class="prettyprint lang-config">
1332 ErrorDocument 404 /cgi-bin/bad_urls.pl
1334 <Directory /web/docs>
1335 ErrorDocument 404 default
1340 <p>Note that when you specify an <code class="directive">ErrorDocument</code>
1341 that points to a remote URL (ie. anything with a method such as
1342 <code>http</code> in front of it), Apache HTTP Server will send a redirect to the
1343 client to tell it where to find the document, even if the
1344 document ends up being on the same server. This has several
1345 implications, the most important being that the client will not
1346 receive the original error status code, but instead will
1347 receive a redirect status code. This in turn can confuse web
1348 robots and other clients which try to determine if a URL is
1349 valid using the status code. In addition, if you use a remote
1350 URL in an <code>ErrorDocument 401</code>, the client will not
1351 know to prompt the user for a password since it will not
1352 receive the 401 status code. Therefore, <strong>if you use an
1353 <code>ErrorDocument 401</code> directive then it must refer to a local
1354 document.</strong></p>
1356 <p>Microsoft Internet Explorer (MSIE) will by default ignore
1357 server-generated error messages when they are "too small" and substitute
1358 its own "friendly" error messages. The size threshold varies depending on
1359 the type of error, but in general, if you make your error document
1360 greater than 512 bytes, then MSIE will show the server-generated
1361 error rather than masking it. More information is available in
1362 Microsoft Knowledge Base article <a href="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q294807">Q294807</a>.</p>
1364 <p>Although most error messages can be overridden, there are certain
1365 circumstances where the internal messages are used regardless of the
1366 setting of <code class="directive"><a href="#errordocument">ErrorDocument</a></code>. In
1367 particular, if a malformed request is detected, normal request processing
1368 will be immediately halted and the internal error message returned.
1369 This is necessary to guard against security problems caused by
1372 <p>If you are using mod_proxy, you may wish to enable
1373 <code class="directive"><a href="../mod/mod_proxy.html#proxyerroroverride">ProxyErrorOverride</a></code> so that you can provide
1374 custom error messages on behalf of your Origin servers. If you don't enable ProxyErrorOverride,
1375 Apache httpd will not generate custom error documents for proxied content.</p>
1379 <li><a href="../custom-error.html">documentation of
1380 customizable responses</a></li>
1383 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1384 <div class="directive-section"><h2><a name="ErrorLog" id="ErrorLog">ErrorLog</a> <a name="errorlog" id="errorlog">Directive</a></h2>
1385 <table class="directive">
1386 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Location where the server will log errors</td></tr>
1387 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code> ErrorLog <var>file-path</var>|syslog[:<var>facility</var>]</code></td></tr>
1388 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ErrorLog logs/error_log (Unix) ErrorLog logs/error.log (Windows and OS/2)</code></td></tr>
1389 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1390 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1391 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1393 <p>The <code class="directive">ErrorLog</code> directive sets the name of
1394 the file to which the server will log any errors it encounters. If
1395 the <var>file-path</var> is not absolute then it is assumed to be
1396 relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1398 <pre class="prettyprint lang-config">ErrorLog "/var/log/httpd/error_log"</pre>
1401 <p>If the <var>file-path</var>
1402 begins with a pipe character "<code>|</code>" then it is assumed to be a
1403 command to spawn to handle the error log.</p>
1405 <pre class="prettyprint lang-config">ErrorLog "|/usr/local/bin/httpd_errors"</pre>
1408 <p>See the notes on <a href="../logs.html#piped">piped logs</a> for
1409 more information.</p>
1411 <p>Using <code>syslog</code> instead of a filename enables logging
1412 via syslogd(8) if the system supports it and if <code class="module"><a href="../mod/mod_syslog.html">mod_syslog</a></code>
1413 is loaded. The default is to use syslog facility <code>local7</code>,
1414 but you can override this by using the <code>syslog:<var>facility</var></code>
1415 syntax where <var>facility</var> can be one of the names usually documented in
1416 syslog(1). The facility is effectively global, and if it is changed
1417 in individual virtual hosts, the final facility specified affects the
1420 <pre class="prettyprint lang-config">ErrorLog syslog:user</pre>
1423 <p>Additional modules can provide their own ErrorLog providers. The syntax
1424 is similar to <code>syslog</code> example above.</p>
1426 <p>SECURITY: See the <a href="../misc/security_tips.html#serverroot">security tips</a>
1427 document for details on why your security could be compromised
1428 if the directory where log files are stored is writable by
1429 anyone other than the user that starts the server.</p>
1430 <div class="warning"><h3>Note</h3>
1431 <p>When entering a file path on non-Unix platforms, care should be taken
1432 to make sure that only forward slashes are used even though the platform
1433 may allow the use of back slashes. In general it is a good idea to always
1434 use forward slashes throughout the configuration files.</p>
1439 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1440 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1443 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1444 <div class="directive-section"><h2><a name="ErrorLogFormat" id="ErrorLogFormat">ErrorLogFormat</a> <a name="errorlogformat" id="errorlogformat">Directive</a></h2>
1445 <table class="directive">
1446 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Format specification for error log entries</td></tr>
1447 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code> ErrorLogFormat [connection|request] <var>format</var></code></td></tr>
1448 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1449 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1450 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1451 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.3.9 and later</td></tr>
1453 <p><code class="directive">ErrorLogFormat</code> allows to specify what
1454 supplementary information is logged in the error log in addition to the
1455 actual log message.</p>
1457 <pre class="prettyprint lang-config">
1459 ErrorLogFormat "[%t] [%l] [pid %P] %F: %E: [client %a] %M"
1463 <p>Specifying <code>connection</code> or <code>request</code> as first
1464 parameter allows to specify additional formats, causing additional
1465 information to be logged when the first message is logged for a specific
1466 connection or request, respectively. This additional information is only
1467 logged once per connection/request. If a connection or request is processed
1468 without causing any log message, the additional information is not logged
1471 <p>It can happen that some format string items do not produce output. For
1472 example, the Referer header is only present if the log message is
1473 associated to a request and the log message happens at a time when the
1474 Referer header has already been read from the client. If no output is
1475 produced, the default behavior is to delete everything from the preceding
1476 space character to the next space character. This means the log line is
1477 implicitly divided into fields on non-whitespace to whitespace transitions.
1478 If a format string item does not produce output, the whole field is
1479 omitted. For example, if the remote address <code>%a</code> in the log
1480 format <code>[%t] [%l] [%a] %M </code> is not available, the surrounding
1481 brackets are not logged either. Space characters can be escaped with a
1482 backslash to prevent them from delimiting a field. The combination '% '
1483 (percent space) is a zero-width field delimiter that does not produce any
1486 <p>The above behavior can be changed by adding modifiers to the format
1487 string item. A <code>-</code> (minus) modifier causes a minus to be logged if the
1488 respective item does not produce any output. In once-per-connection/request
1489 formats, it is also possible to use the <code>+</code> (plus) modifier. If an
1490 item with the plus modifier does not produce any output, the whole line is
1493 <p>A number as modifier can be used to assign a log severity level to a
1494 format item. The item will only be logged if the severity of the log
1495 message is not higher than the specified log severity level. The number can
1496 range from 1 (alert) over 4 (warn) and 7 (debug) to 15 (trace8).</p>
1498 <p>For example, here's what would happen if you added modifiers to
1499 the <code>%{Referer}i</code> token, which logs the
1500 <code>Referer</code> request header.</p>
1502 <table class="bordered"><tr class="header"><th>Modified Token</th><th>Meaning</th></tr>
1504 <td><code>%-{Referer}i</code></td>
1505 <td>Logs a <code>-</code> if <code>Referer</code> is not set.</td>
1508 <td><code>%+{Referer}i</code></td>
1509 <td>Omits the entire line if <code>Referer</code> is not set.</td>
1512 <td><code>%4{Referer}i</code></td>
1513 <td>Logs the <code>Referer</code> only if the log message severity
1514 is higher than 4.</td>
1518 <p>Some format string items accept additional parameters in braces.</p>
1520 <table class="bordered"><tr class="header"><th>Format String</th> <th>Description</th></tr>
1521 <tr><td><code>%%</code></td>
1522 <td>The percent sign</td></tr>
1523 <tr class="odd"><td><code>%a</code></td>
1524 <td>Client IP address and port of the request</td></tr>
1525 <tr><td><code>%{c}a</code></td>
1526 <td>Underlying peer IP address and port of the connection (see the
1527 <code class="module"><a href="../mod/mod_remoteip.html">mod_remoteip</a></code> module)</td></tr>
1528 <tr class="odd"><td><code>%A</code></td>
1529 <td>Local IP-address and port</td></tr>
1530 <tr><td><code>%{<em>name</em>}e</code></td>
1531 <td>Request environment variable <em>name</em></td></tr>
1532 <tr class="odd"><td><code>%E</code></td>
1533 <td>APR/OS error status code and string</td></tr>
1534 <tr><td><code>%F</code></td>
1535 <td>Source file name and line number of the log call</td></tr>
1536 <tr class="odd"><td><code>%{<em>name</em>}i</code></td>
1537 <td>Request header <em>name</em></td></tr>
1538 <tr><td><code>%k</code></td>
1539 <td>Number of keep-alive requests on this connection</td></tr>
1540 <tr class="odd"><td><code>%l</code></td>
1541 <td>Loglevel of the message</td></tr>
1542 <tr><td><code>%L</code></td>
1543 <td>Log ID of the request</td></tr>
1544 <tr class="odd"><td><code>%{c}L</code></td>
1545 <td>Log ID of the connection</td></tr>
1546 <tr><td><code>%{C}L</code></td>
1547 <td>Log ID of the connection if used in connection scope, empty otherwise</td></tr>
1548 <tr class="odd"><td><code>%m</code></td>
1549 <td>Name of the module logging the message</td></tr>
1550 <tr><td><code>%M</code></td>
1551 <td>The actual log message</td></tr>
1552 <tr class="odd"><td><code>%{<em>name</em>}n</code></td>
1553 <td>Request note <em>name</em></td></tr>
1554 <tr><td><code>%P</code></td>
1555 <td>Process ID of current process</td></tr>
1556 <tr class="odd"><td><code>%T</code></td>
1557 <td>Thread ID of current thread</td></tr>
1558 <tr><td><code>%{g}T</code></td>
1559 <td>System unique thread ID of current thread (the same ID as
1560 displayed by e.g. <code>top</code>; currently Linux only)</td></tr>
1561 <tr class="odd"><td><code>%t</code></td>
1562 <td>The current time</td></tr>
1563 <tr><td><code>%{u}t</code></td>
1564 <td>The current time including micro-seconds</td></tr>
1565 <tr class="odd"><td><code>%{cu}t</code></td>
1566 <td>The current time in compact ISO 8601 format, including
1567 micro-seconds</td></tr>
1568 <tr><td><code>%v</code></td>
1569 <td>The canonical <code class="directive"><a href="#servername">ServerName</a></code>
1570 of the current server.</td></tr>
1571 <tr class="odd"><td><code>%V</code></td>
1572 <td>The server name of the server serving the request according to the
1573 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code>
1575 <tr><td><code>\ </code> (backslash space)</td>
1576 <td>Non-field delimiting space</td></tr>
1577 <tr class="odd"><td><code>% </code> (percent space)</td>
1578 <td>Field delimiter (no output)</td></tr>
1581 <p>The log ID format <code>%L</code> produces a unique id for a connection
1582 or request. This can be used to correlate which log lines belong to the
1583 same connection or request, which request happens on which connection.
1584 A <code>%L</code> format string is also available in
1585 <code class="module"><a href="../mod/mod_log_config.html">mod_log_config</a></code>, to allow to correlate access log entries
1586 with error log lines. If <code class="module"><a href="../mod/mod_unique_id.html">mod_unique_id</a></code> is loaded, its
1587 unique id will be used as log ID for requests.</p>
1589 <pre class="prettyprint lang-config">
1590 #Example (default format for threaded MPMs)
1591 ErrorLogFormat "[%{u}t] [%-m:%l] [pid %P:tid %T] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"
1595 <p>This would result in error messages such as:</p>
1597 <div class="example"><p><code>
1598 [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
1601 <p>Notice that, as discussed above, some fields are omitted
1602 entirely because they are not defined.</p>
1604 <pre class="prettyprint lang-config">
1605 #Example (similar to the 2.2.x format)
1606 ErrorLogFormat "[%t] [%l] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"
1610 <pre class="prettyprint lang-config">
1611 #Advanced example with request/connection log IDs
1612 ErrorLogFormat "[%{uc}t] [%-m:%-l] [R:%L] [C:%{C}L] %7F: %E: %M"
1613 ErrorLogFormat request "[%{uc}t] [R:%L] Request %k on C:%{c}L pid:%P tid:%T"
1614 ErrorLogFormat request "[%{uc}t] [R:%L] UA:'%+{User-Agent}i'"
1615 ErrorLogFormat request "[%{uc}t] [R:%L] Referer:'%+{Referer}i'"
1616 ErrorLogFormat connection "[%{uc}t] [C:%{c}L] local\ %a remote\ %A"
1623 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
1624 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1625 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1628 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1629 <div class="directive-section"><h2><a name="ExtendedStatus" id="ExtendedStatus">ExtendedStatus</a> <a name="extendedstatus" id="extendedstatus">Directive</a></h2>
1630 <table class="directive">
1631 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Keep track of extended status information for each
1633 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ExtendedStatus On|Off</code></td></tr>
1634 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ExtendedStatus Off[*]</code></td></tr>
1635 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
1636 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1637 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1639 <p>This option tracks additional data per worker about the
1640 currently executing request, and a utilization summary; you
1641 can see these variables during runtime by configuring
1642 <code class="module"><a href="../mod/mod_status.html">mod_status</a></code>. Note that other modules may
1643 rely on this scoreboard.</p>
1645 <p>This setting applies to the entire server, and cannot be
1646 enabled or disabled on a virtualhost-by-virtualhost basis.
1647 The collection of extended status information can slow down
1648 the server. Also note that this setting cannot be changed
1649 during a graceful restart.</p>
1652 <p>Note that loading <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> will change
1653 the default behavior to ExtendedStatus On, while other
1654 third party modules may do the same. Such modules rely on
1655 collecting detailed information about the state of all workers.
1656 The default is changed by <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> beginning
1657 with version 2.3.6; the previous default was always Off.</p>
1662 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1663 <div class="directive-section"><h2><a name="FileETag" id="FileETag">FileETag</a> <a name="fileetag" id="fileetag">Directive</a></h2>
1664 <table class="directive">
1665 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>File attributes used to create the ETag
1666 HTTP response header for static files</td></tr>
1667 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>FileETag <var>component</var> ...</code></td></tr>
1668 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>FileETag MTime Size</code></td></tr>
1669 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1670 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1671 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1672 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1673 <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
1677 The <code class="directive">FileETag</code> directive configures the file
1678 attributes that are used to create the <code>ETag</code> (entity
1679 tag) response header field when the document is based on a static file.
1680 (The <code>ETag</code> value is used in cache management to save
1681 network bandwidth.) The
1682 <code class="directive">FileETag</code> directive allows you to choose
1683 which of these -- if any -- should be used. The recognized keywords are:
1687 <dt><strong>INode</strong></dt>
1688 <dd>The file's i-node number will be included in the calculation</dd>
1689 <dt><strong>MTime</strong></dt>
1690 <dd>The date and time the file was last modified will be included</dd>
1691 <dt><strong>Size</strong></dt>
1692 <dd>The number of bytes in the file will be included</dd>
1693 <dt><strong>All</strong></dt>
1694 <dd>All available fields will be used. This is equivalent to:
1695 <pre class="prettyprint lang-config">FileETag INode MTime Size</pre>
1697 <dt><strong>None</strong></dt>
1698 <dd>If a document is file-based, no <code>ETag</code> field will be
1699 included in the response</dd>
1702 <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
1703 keywords may be prefixed with either <code>+</code> or <code>-</code>,
1704 which allow changes to be made to the default setting inherited
1705 from a broader scope. Any keyword appearing without such a prefix
1706 immediately and completely cancels the inherited setting.</p>
1708 <p>If a directory's configuration includes
1709 <code>FileETag INode MTime Size</code>, and a
1710 subdirectory's includes <code>FileETag -INode</code>,
1711 the setting for that subdirectory (which will be inherited by
1712 any sub-subdirectories that don't override it) will be equivalent to
1713 <code>FileETag MTime Size</code>.</p>
1714 <div class="warning"><h3>Warning</h3>
1715 Do not change the default for directories or locations that have WebDAV
1716 enabled and use <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> as a storage provider.
1717 <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> uses <code>MTime Size</code>
1718 as a fixed format for <code>ETag</code> comparisons on conditional requests.
1719 These conditional requests will break if the <code>ETag</code> format is
1720 changed via <code class="directive">FileETag</code>.
1722 <div class="note"><h3>Server Side Includes</h3>
1723 An ETag is not generated for responses parsed by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>,
1724 since the response entity can change without a change of the INode, MTime, or Size
1725 of the static file with embedded SSI directives.
1730 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1731 <div class="directive-section"><h2><a name="Files" id="Files"><Files></a> <a name="files" id="files">Directive</a></h2>
1732 <table class="directive">
1733 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to matched
1735 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Files <var>filename</var>> ... </Files></code></td></tr>
1736 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1737 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1738 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1739 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1741 <p>The <code class="directive"><Files></code> directive
1742 limits the scope of the enclosed directives by filename. It is comparable
1743 to the <code class="directive"><a href="#directory"><Directory></a></code>
1744 and <code class="directive"><a href="#location"><Location></a></code>
1745 directives. It should be matched with a <code></Files></code>
1746 directive. The directives given within this section will be applied to
1747 any object with a basename (last component of filename) matching the
1748 specified filename. <code class="directive"><Files></code>
1749 sections are processed in the order they appear in the
1750 configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
1751 <code>.htaccess</code> files are read, but before <code class="directive"><a href="#location"><Location></a></code> sections. Note
1752 that <code class="directive"><Files></code> can be nested
1753 inside <code class="directive"><a href="#directory"><Directory></a></code> sections to restrict the
1754 portion of the filesystem they apply to.</p>
1756 <p>The <var>filename</var> argument should include a filename, or
1757 a wild-card string, where <code>?</code> matches any single character,
1758 and <code>*</code> matches any sequences of characters.</p>
1759 <pre class="prettyprint lang-config">
1760 <Files "cat.html">
1761 # Insert stuff that applies to cat.html here
1764 <Files "?at.*">
1765 # This would apply to cat.html, bat.html, hat.php and so on.
1769 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
1770 can also be used, with the addition of the
1771 <code>~</code> character. For example:</p>
1773 <pre class="prettyprint lang-config">
1774 <Files ~ "\.(gif|jpe?g|png)$">
1780 <p>would match most common Internet graphics formats. <code class="directive"><a href="#filesmatch"><FilesMatch></a></code> is preferred,
1783 <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
1784 <code>.htaccess</code> files. This allows users to control access to
1785 their own files, at a file-by-file level.</p>
1790 <li><a href="../sections.html">How <Directory>, <Location>
1791 and <Files> sections work</a> for an explanation of how these
1792 different sections are combined when a request is received</li>
1795 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1796 <div class="directive-section"><h2><a name="FilesMatch" id="FilesMatch"><FilesMatch></a> <a name="filesmatch" id="filesmatch">Directive</a></h2>
1797 <table class="directive">
1798 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to regular-expression matched
1800 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><FilesMatch <var>regex</var>> ... </FilesMatch></code></td></tr>
1801 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1802 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1803 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1804 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1806 <p>The <code class="directive"><FilesMatch></code> directive
1807 limits the scope of the enclosed directives by filename, just as the
1808 <code class="directive"><a href="#files"><Files></a></code> directive
1809 does. However, it accepts a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular
1810 expression</a>. For example:</p>
1812 <pre class="prettyprint lang-config">
1813 <FilesMatch "\.(gif|jpe?g|png)$">
1819 <p>would match most common Internet graphics formats.</p>
1821 <p>From 2.4.8 onwards, named groups and backreferences are captured and
1822 written to the environment with the corresponding name prefixed with
1823 "MATCH_" and in upper case. This allows elements of files to be referenced
1824 from within <a href="expr.html">expressions</a> and modules like
1825 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
1826 (unnamed) backreferences are ignored. Use named groups instead.</p>
1828 <pre class="prettyprint lang-config">
1829 <FileMatch ^(?<sitename>[^/]+)>
1830 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
1837 <li><a href="../sections.html">How <Directory>, <Location>
1838 and <Files> sections work</a> for an explanation of how these
1839 different sections are combined when a request is received</li>
1842 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1843 <div class="directive-section"><h2><a name="ForceType" id="ForceType">ForceType</a> <a name="forcetype" id="forcetype">Directive</a></h2>
1844 <table class="directive">
1845 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be served with the specified
1846 media type in the HTTP Content-Type header field</td></tr>
1847 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ForceType <var>media-type</var>|None</code></td></tr>
1848 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
1849 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1850 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1851 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1853 <p>When placed into an <code>.htaccess</code> file or a
1854 <code class="directive"><a href="#directory"><Directory></a></code>, or
1855 <code class="directive"><a href="#location"><Location></a></code> or
1856 <code class="directive"><a href="#files"><Files></a></code>
1857 section, this directive forces all matching files to be served
1858 with the content type identification given by
1859 <var>media-type</var>. For example, if you had a directory full of
1860 GIF files, but did not want to label them all with <code>.gif</code>,
1861 you might want to use:</p>
1863 <pre class="prettyprint lang-config">ForceType image/gif</pre>
1866 <p>Note that this directive overrides other indirect media type
1867 associations defined in mime.types or via the
1868 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code>.</p>
1870 <p>You can also override more general
1871 <code class="directive">ForceType</code> settings
1872 by using the value of <code>None</code>:</p>
1874 <pre class="prettyprint lang-config">
1875 # force all files to be image/gif:
1876 <Location /images>
1880 # but normal mime-type associations here:
1881 <Location /images/mixed>
1887 <p>This directive primarily overrides the content types generated for
1888 static files served out of the filesystem. For resources other than
1889 static files, where the generator of the response typically specifies
1890 a Content-Type, this directive has no effect.</p>
1894 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1895 <div class="directive-section"><h2><a name="GprofDir" id="GprofDir">GprofDir</a> <a name="gprofdir" id="gprofdir">Directive</a></h2>
1896 <table class="directive">
1897 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory to write gmon.out profiling data to. </td></tr>
1898 <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>
1899 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1900 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1901 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1903 <p>When the server has been compiled with gprof profiling support,
1904 <code class="directive">GprofDir</code> causes <code>gmon.out</code> files to
1905 be written to the specified directory when the process exits. If the
1906 argument ends with a percent symbol ('%'), subdirectories are created
1907 for each process id.</p>
1909 <p>This directive currently only works with the <code class="module"><a href="../mod/prefork.html">prefork</a></code>
1913 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1914 <div class="directive-section"><h2><a name="HostnameLookups" id="HostnameLookups">HostnameLookups</a> <a name="hostnamelookups" id="hostnamelookups">Directive</a></h2>
1915 <table class="directive">
1916 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables DNS lookups on client IP addresses</td></tr>
1917 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>HostnameLookups On|Off|Double</code></td></tr>
1918 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>HostnameLookups Off</code></td></tr>
1919 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1920 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1921 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1923 <p>This directive enables DNS lookups so that host names can be
1924 logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
1925 The value <code>Double</code> refers to doing double-reverse
1926 DNS lookup. That is, after a reverse lookup is performed, a forward
1927 lookup is then performed on that result. At least one of the IP
1928 addresses in the forward lookup must match the original
1929 address. (In "tcpwrappers" terminology this is called
1930 <code>PARANOID</code>.)</p>
1932 <p>Regardless of the setting, when <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code> is
1933 used for controlling access by hostname, a double reverse lookup
1934 will be performed. This is necessary for security. Note that the
1935 result of this double-reverse isn't generally available unless you
1936 set <code>HostnameLookups Double</code>. For example, if only
1937 <code>HostnameLookups On</code> and a request is made to an object
1938 that is protected by hostname restrictions, regardless of whether
1939 the double-reverse fails or not, CGIs will still be passed the
1940 single-reverse result in <code>REMOTE_HOST</code>.</p>
1942 <p>The default is <code>Off</code> in order to save the network
1943 traffic for those sites that don't truly need the reverse
1944 lookups done. It is also better for the end users because they
1945 don't have to suffer the extra latency that a lookup entails.
1946 Heavily loaded sites should leave this directive
1947 <code>Off</code>, since DNS lookups can take considerable
1948 amounts of time. The utility <code class="program"><a href="../programs/logresolve.html">logresolve</a></code>, compiled by
1949 default to the <code>bin</code> subdirectory of your installation
1950 directory, can be used to look up host names from logged IP addresses
1953 <p>Finally, if you have <a href="mod_authz_host.html#reqhost">hostname-based Require
1954 directives</a>, a hostname lookup will be performed regardless of
1955 the setting of <code>HostnameLookups</code>.</p>
1958 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1959 <div class="directive-section"><h2><a name="If" id="If"><If></a> <a name="if" id="if">Directive</a></h2>
1960 <table class="directive">
1961 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is
1962 satisfied by a request at runtime</td></tr>
1963 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><If <var>expression</var>> ... </If></code></td></tr>
1964 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1965 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1966 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1967 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1969 <p>The <code class="directive"><If></code> directive
1970 evaluates an expression at runtime, and applies the enclosed
1971 directives if and only if the expression evaluates to true.
1974 <pre class="prettyprint lang-config"><If "-z req('Host')"></pre>
1977 <p>would match HTTP/1.0 requests without a <var>Host:</var> header.
1978 Expressions may contain various shell-like operators for string
1979 comparison (<code>=</code>, <code>!=</code>, <code><</code>, ...),
1980 integer comparison (<code>-eq</code>, <code>-ne</code>, ...),
1981 and others (<code>-n</code>, <code>-z</code>, <code>-f</code>, ...).
1982 It is also possible to use regular expressions, </p>
1984 <pre class="prettyprint lang-config"><If "%{QUERY_STRING} =~ /(delete|commit)=.*?elem/"></pre>
1987 <p>shell-like pattern matches and many other operations. These operations
1988 can be done on request headers (<code>req</code>), environment variables
1989 (<code>env</code>), and a large number of other properties. The full
1990 documentation is available in <a href="../expr.html">Expressions in
1991 Apache HTTP Server</a>.</p>
1993 <p>Only directives that support the <a href="mod/directive-dict.html#Context">directory context</a> can be used within this configuration section.</p>
1998 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
1999 for a complete reference and more examples.</li>
2000 <li><code class="directive"><a href="#elseif"><ElseIf></a></code></li>
2001 <li><code class="directive"><a href="#else"><Else></a></code></li>
2002 <li><a href="../sections.html">How <Directory>, <Location>,
2003 <Files> sections work</a> for an explanation of how these
2004 different sections are combined when a request is received.
2005 <code class="directive"><If></code>,
2006 <code class="directive"><ElseIf></code>, and
2007 <code class="directive"><Else></code> are applied last.</li>
2010 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2011 <div class="directive-section"><h2><a name="IfDefine" id="IfDefine"><IfDefine></a> <a name="ifdefine" id="ifdefine">Directive</a></h2>
2012 <table class="directive">
2013 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that will be processed only
2014 if a test is true at startup</td></tr>
2015 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfDefine [!]<var>parameter-name</var>> ...
2016 </IfDefine></code></td></tr>
2017 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2018 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2019 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2020 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2022 <p>The <code><IfDefine <var>test</var>>...</IfDefine>
2023 </code> section is used to mark directives that are conditional. The
2024 directives within an <code class="directive"><IfDefine></code>
2025 section are only processed if the <var>test</var> is true. If <var>
2026 test</var> is false, everything between the start and end markers is
2029 <p>The <var>test</var> in the <code class="directive"><IfDefine></code> section directive can be one of two forms:</p>
2032 <li><var>parameter-name</var></li>
2034 <li><code>!</code><var>parameter-name</var></li>
2037 <p>In the former case, the directives between the start and end
2038 markers are only processed if the parameter named
2039 <var>parameter-name</var> is defined. The second format reverses
2040 the test, and only processes the directives if
2041 <var>parameter-name</var> is <strong>not</strong> defined.</p>
2043 <p>The <var>parameter-name</var> argument is a define as given on the
2044 <code class="program"><a href="../programs/httpd.html">httpd</a></code> command line via <code>-D<var>parameter</var>
2045 </code> at the time the server was started or by the <code class="directive"><a href="#define">Define</a></code> directive.</p>
2047 <p><code class="directive"><IfDefine></code> sections are
2048 nest-able, which can be used to implement simple
2049 multiple-parameter tests. Example:</p>
2051 <div class="example"><p><code>httpd -DReverseProxy -DUseCache -DMemCache ...</code></p></div>
2052 <pre class="prettyprint lang-config">
2053 <IfDefine ReverseProxy>
2054 LoadModule proxy_module modules/mod_proxy.so
2055 LoadModule proxy_http_module modules/mod_proxy_http.so
2056 <IfDefine UseCache>
2057 LoadModule cache_module modules/mod_cache.so
2058 <IfDefine MemCache>
2059 LoadModule mem_cache_module modules/mod_mem_cache.so
2061 <IfDefine !MemCache>
2062 LoadModule cache_disk_module modules/mod_cache_disk.so
2070 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2071 <div class="directive-section"><h2><a name="IfModule" id="IfModule"><IfModule></a> <a name="ifmodule" id="ifmodule">Directive</a></h2>
2072 <table class="directive">
2073 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that are processed conditional on the
2074 presence or absence of a specific module</td></tr>
2075 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfModule [!]<var>module-file</var>|<var>module-identifier</var>> ...
2076 </IfModule></code></td></tr>
2077 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2078 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2079 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2080 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2082 <p>The <code><IfModule <var>test</var>>...</IfModule></code>
2083 section is used to mark directives that are conditional on the presence of
2084 a specific module. The directives within an <code class="directive"><IfModule></code> section are only processed if the <var>test</var>
2085 is true. If <var>test</var> is false, everything between the start and
2086 end markers is ignored.</p>
2088 <p>The <var>test</var> in the <code class="directive"><IfModule></code> section directive can be one of two forms:</p>
2091 <li><var>module</var></li>
2093 <li>!<var>module</var></li>
2096 <p>In the former case, the directives between the start and end
2097 markers are only processed if the module named <var>module</var>
2098 is included in Apache httpd -- either compiled in or
2099 dynamically loaded using <code class="directive"><a href="../mod/mod_so.html#loadmodule">LoadModule</a></code>. The second format reverses the test,
2100 and only processes the directives if <var>module</var> is
2101 <strong>not</strong> included.</p>
2103 <p>The <var>module</var> argument can be either the module identifier or
2104 the file name of the module, at the time it was compiled. For example,
2105 <code>rewrite_module</code> is the identifier and
2106 <code>mod_rewrite.c</code> is the file name. If a module consists of
2107 several source files, use the name of the file containing the string
2108 <code>STANDARD20_MODULE_STUFF</code>.</p>
2110 <p><code class="directive"><IfModule></code> sections are
2111 nest-able, which can be used to implement simple multiple-module
2114 <div class="note">This section should only be used if you need to have one
2115 configuration file that works whether or not a specific module
2116 is available. In normal operation, directives need not be
2117 placed in <code class="directive"><IfModule></code>
2121 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2122 <div class="directive-section"><h2><a name="Include" id="Include">Include</a> <a name="include" id="include">Directive</a></h2>
2123 <table class="directive">
2124 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2125 the server configuration files</td></tr>
2126 <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>
2127 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2128 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2129 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2130 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Directory
2131 wildcard matching available in 2.3.6 and later</td></tr>
2133 <p>This directive allows inclusion of other configuration files
2134 from within the server configuration files.</p>
2136 <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used
2137 in the filename or directory parts of the path to include several files
2138 at once, in alphabetical order. In addition, if
2139 <code class="directive">Include</code> points to a directory, rather than a file,
2140 Apache httpd will read all files in that directory and any subdirectory.
2141 However, including entire directories is not recommended, because it is
2142 easy to accidentally leave temporary files in a directory that can cause
2143 <code class="program"><a href="../programs/httpd.html">httpd</a></code> to fail. Instead, we encourage you to use the
2144 wildcard syntax shown below, to include files that match a particular
2145 pattern, such as *.conf, for example.</p>
2147 <p>The <code class="directive"><a href="#include">Include</a></code> directive will
2148 <strong>fail with an error</strong> if a wildcard expression does not
2149 match any file. The <code class="directive"><a href="#includeoptional">IncludeOptional</a></code>
2150 directive can be used if non-matching wildcards should be ignored.</p>
2152 <p>The file path specified may be an absolute path, or may be relative
2153 to the <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory.</p>
2157 <pre class="prettyprint lang-config">
2158 Include /usr/local/apache2/conf/ssl.conf
2159 Include /usr/local/apache2/conf/vhosts/*.conf
2163 <p>Or, providing paths relative to your <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory:</p>
2165 <pre class="prettyprint lang-config">
2166 Include conf/ssl.conf
2167 Include conf/vhosts/*.conf
2171 <p>Wildcards may be included in the directory or file portion of the
2172 path. This example will fail if there is no subdirectory in conf/vhosts
2173 that contains at least one *.conf file:</p>
2175 <pre class="prettyprint lang-config">Include conf/vhosts/*/*.conf</pre>
2178 <p>Alternatively, the following command will just be ignored in case of
2179 missing files or directories:</p>
2181 <pre class="prettyprint lang-config">IncludeOptional conf/vhosts/*/*.conf</pre>
2187 <li><code class="directive"><a href="#includeoptional">IncludeOptional</a></code></li>
2188 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2191 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2192 <div class="directive-section"><h2><a name="IncludeOptional" id="IncludeOptional">IncludeOptional</a> <a name="includeoptional" id="includeoptional">Directive</a></h2>
2193 <table class="directive">
2194 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2195 the server configuration files</td></tr>
2196 <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>
2197 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2198 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2199 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2200 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in 2.3.6 and later</td></tr>
2202 <p>This directive allows inclusion of other configuration files
2203 from within the server configuration files. It works identically to the
2204 <code class="directive"><a href="#include">Include</a></code> directive, with the
2205 exception that if wildcards do not match any file or directory, the
2206 <code class="directive"><a href="#includeoptional">IncludeOptional</a></code> directive will be
2207 silently ignored instead of causing an error.</p>
2211 <li><code class="directive"><a href="#include">Include</a></code></li>
2212 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2215 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2216 <div class="directive-section"><h2><a name="KeepAlive" id="KeepAlive">KeepAlive</a> <a name="keepalive" id="keepalive">Directive</a></h2>
2217 <table class="directive">
2218 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables HTTP persistent connections</td></tr>
2219 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAlive On|Off</code></td></tr>
2220 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAlive On</code></td></tr>
2221 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2222 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2223 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2225 <p>The Keep-Alive extension to HTTP/1.0 and the persistent
2226 connection feature of HTTP/1.1 provide long-lived HTTP sessions
2227 which allow multiple requests to be sent over the same TCP
2228 connection. In some cases this has been shown to result in an
2229 almost 50% speedup in latency times for HTML documents with
2230 many images. To enable Keep-Alive connections, set
2231 <code>KeepAlive On</code>.</p>
2233 <p>For HTTP/1.0 clients, Keep-Alive connections will only be
2234 used if they are specifically requested by a client. In
2235 addition, a Keep-Alive connection with an HTTP/1.0 client can
2236 only be used when the length of the content is known in
2237 advance. This implies that dynamic content such as CGI output,
2238 SSI pages, and server-generated directory listings will
2239 generally not use Keep-Alive connections to HTTP/1.0 clients.
2240 For HTTP/1.1 clients, persistent connections are the default
2241 unless otherwise specified. If the client requests it, chunked
2242 encoding will be used in order to send content of unknown
2243 length over persistent connections.</p>
2245 <p>When a client uses a Keep-Alive connection it will be counted
2246 as a single "request" for the <code class="directive"><a href="../mod/mpm_common.html#maxconnectionsperchild">MaxConnectionsPerChild</a></code> directive, regardless
2247 of how many requests are sent using the connection.</p>
2251 <li><code class="directive"><a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></code></li>
2254 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2255 <div class="directive-section"><h2><a name="KeepAliveTimeout" id="KeepAliveTimeout">KeepAliveTimeout</a> <a name="keepalivetimeout" id="keepalivetimeout">Directive</a></h2>
2256 <table class="directive">
2257 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for subsequent
2258 requests on a persistent connection</td></tr>
2259 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAliveTimeout <var>num</var>[ms]</code></td></tr>
2260 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAliveTimeout 5</code></td></tr>
2261 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2262 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2263 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2264 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Specifying a value in milliseconds is available in
2265 Apache httpd 2.3.2 and later</td></tr>
2267 <p>The number of seconds Apache httpd will wait for a subsequent
2268 request before closing the connection. By adding a postfix of ms the
2269 timeout can be also set in milliseconds. Once a request has been
2270 received, the timeout value specified by the
2271 <code class="directive"><a href="#timeout">Timeout</a></code> directive applies.</p>
2273 <p>Setting <code class="directive">KeepAliveTimeout</code> to a high value
2274 may cause performance problems in heavily loaded servers. The
2275 higher the timeout, the more server processes will be kept
2276 occupied waiting on connections with idle clients.</p>
2278 <p>In a name-based virtual host context, the value of the first
2279 defined virtual host best matching the local IP and port will be used.</p>
2282 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2283 <div class="directive-section"><h2><a name="Limit" id="Limit"><Limit></a> <a name="limit" id="limit">Directive</a></h2>
2284 <table class="directive">
2285 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict enclosed access controls to only certain HTTP
2287 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Limit <var>method</var> [<var>method</var>] ... > ...
2288 </Limit></code></td></tr>
2289 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2290 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2291 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2292 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2294 <p>Access controls are normally effective for
2295 <strong>all</strong> access methods, and this is the usual
2296 desired behavior. <strong>In the general case, access control
2297 directives should not be placed within a
2298 <code class="directive"><Limit></code> section.</strong></p>
2300 <p>The purpose of the <code class="directive"><Limit></code>
2301 directive is to restrict the effect of the access controls to the
2302 nominated HTTP methods. For all other methods, the access
2303 restrictions that are enclosed in the <code class="directive"><Limit></code> bracket <strong>will have no
2304 effect</strong>. The following example applies the access control
2305 only to the methods <code>POST</code>, <code>PUT</code>, and
2306 <code>DELETE</code>, leaving all other methods unprotected:</p>
2308 <pre class="prettyprint lang-config">
2309 <Limit POST PUT DELETE>
2315 <p>The method names listed can be one or more of: <code>GET</code>,
2316 <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
2317 <code>CONNECT</code>, <code>OPTIONS</code>,
2318 <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
2319 <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
2320 <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
2321 case-sensitive.</strong> If <code>GET</code> is used it will also
2322 restrict <code>HEAD</code> requests. The <code>TRACE</code> method
2323 cannot be limited (see <code class="directive"><a href="#traceenable">TraceEnable</a></code>).</p>
2325 <div class="warning">A <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section should always be
2326 used in preference to a <code class="directive"><Limit></code>
2327 section when restricting access, since a <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section provides protection
2328 against arbitrary methods.</div>
2330 <p>The <code class="directive"><Limit></code> and
2331 <code class="directive"><a href="#limitexcept"><LimitExcept></a></code>
2332 directives may be nested. In this case, each successive level of
2333 <code class="directive"><Limit></code> or <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> directives must
2334 further restrict the set of methods to which access controls apply.</p>
2336 <div class="warning">When using
2337 <code class="directive"><Limit></code> or
2338 <code class="directive"><LimitExcept></code> directives with
2339 the <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directive,
2340 note that the first <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code>
2341 to succeed authorizes the request, regardless of the presence of other
2342 <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directives.</div>
2344 <p>For example, given the following configuration, all users will
2345 be authorized for <code>POST</code> requests, and the
2346 <code>Require group editors</code> directive will be ignored
2349 <pre class="prettyprint lang-config">
2350 <LimitExcept GET>
2352 </LimitExcept>
2354 Require group editors
2360 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2361 <div class="directive-section"><h2><a name="LimitExcept" id="LimitExcept"><LimitExcept></a> <a name="limitexcept" id="limitexcept">Directive</a></h2>
2362 <table class="directive">
2363 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict access controls to all HTTP methods
2364 except the named ones</td></tr>
2365 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LimitExcept <var>method</var> [<var>method</var>] ... > ...
2366 </LimitExcept></code></td></tr>
2367 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2368 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2369 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2370 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2372 <p><code class="directive"><LimitExcept></code> and
2373 <code></LimitExcept></code> are used to enclose
2374 a group of access control directives which will then apply to any
2375 HTTP access method <strong>not</strong> listed in the arguments;
2376 i.e., it is the opposite of a <code class="directive"><a href="#limit"><Limit></a></code> section and can be used to control
2377 both standard and nonstandard/unrecognized methods. See the
2378 documentation for <code class="directive"><a href="#limit"><Limit></a></code> for more details.</p>
2382 <pre class="prettyprint lang-config">
2383 <LimitExcept POST GET>
2385 </LimitExcept>
2391 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2392 <div class="directive-section"><h2><a name="LimitInternalRecursion" id="LimitInternalRecursion">LimitInternalRecursion</a> <a name="limitinternalrecursion" id="limitinternalrecursion">Directive</a></h2>
2393 <table class="directive">
2394 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine maximum number of internal redirects and nested
2395 subrequests</td></tr>
2396 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitInternalRecursion <var>number</var> [<var>number</var>]</code></td></tr>
2397 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitInternalRecursion 10</code></td></tr>
2398 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2399 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2400 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2402 <p>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
2403 redirects the original request to a CGI script. A subrequest is Apache httpd's
2404 mechanism to find out what would happen for some URI if it were requested.
2405 For example, <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> uses subrequests to look for the
2406 files listed in the <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
2409 <p><code class="directive">LimitInternalRecursion</code> prevents the server
2410 from crashing when entering an infinite loop of internal redirects or
2411 subrequests. Such loops are usually caused by misconfigurations.</p>
2413 <p>The directive stores two different limits, which are evaluated on
2414 per-request basis. The first <var>number</var> is the maximum number of
2415 internal redirects, that may follow each other. The second <var>number</var>
2416 determines, how deep subrequests may be nested. If you specify only one
2417 <var>number</var>, it will be assigned to both limits.</p>
2419 <pre class="prettyprint lang-config">LimitInternalRecursion 5</pre>
2423 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2424 <div class="directive-section"><h2><a name="LimitRequestBody" id="LimitRequestBody">LimitRequestBody</a> <a name="limitrequestbody" id="limitrequestbody">Directive</a></h2>
2425 <table class="directive">
2426 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restricts the total size of the HTTP request body sent
2427 from the client</td></tr>
2428 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestBody <var>bytes</var></code></td></tr>
2429 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestBody 0</code></td></tr>
2430 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2431 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2432 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2433 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2435 <p>This directive specifies the number of <var>bytes</var> from 0
2436 (meaning unlimited) to 2147483647 (2GB) that are allowed in a
2437 request body. See the note below for the limited applicability
2438 to proxy requests.</p>
2440 <p>The <code class="directive">LimitRequestBody</code> directive allows
2441 the user to set a limit on the allowed size of an HTTP request
2442 message body within the context in which the directive is given
2443 (server, per-directory, per-file or per-location). If the client
2444 request exceeds that limit, the server will return an error
2445 response instead of servicing the request. The size of a normal
2446 request message body will vary greatly depending on the nature of
2447 the resource and the methods allowed on that resource. CGI scripts
2448 typically use the message body for retrieving form information.
2449 Implementations of the <code>PUT</code> method will require
2450 a value at least as large as any representation that the server
2451 wishes to accept for that resource.</p>
2453 <p>This directive gives the server administrator greater
2454 control over abnormal client request behavior, which may be
2455 useful for avoiding some forms of denial-of-service
2458 <p>If, for example, you are permitting file upload to a particular
2459 location, and wish to limit the size of the uploaded file to 100K,
2460 you might use the following directive:</p>
2462 <pre class="prettyprint lang-config">LimitRequestBody 102400</pre>
2465 <div class="note"><p>For a full description of how this directive is interpreted by
2466 proxy requests, see the <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> documentation.</p>
2471 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2472 <div class="directive-section"><h2><a name="LimitRequestFields" id="LimitRequestFields">LimitRequestFields</a> <a name="limitrequestfields" id="limitrequestfields">Directive</a></h2>
2473 <table class="directive">
2474 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of HTTP request header fields that
2475 will be accepted from the client</td></tr>
2476 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFields <var>number</var></code></td></tr>
2477 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFields 100</code></td></tr>
2478 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2479 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2480 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2482 <p><var>Number</var> is an integer from 0 (meaning unlimited) to
2483 32767. The default value is defined by the compile-time
2484 constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
2487 <p>The <code class="directive">LimitRequestFields</code> directive allows
2488 the server administrator to modify the limit on the number of
2489 request header fields allowed in an HTTP request. A server needs
2490 this value to be larger than the number of fields that a normal
2491 client request might include. The number of request header fields
2492 used by a client rarely exceeds 20, but this may vary among
2493 different client implementations, often depending upon the extent
2494 to which a user has configured their browser to support detailed
2495 content negotiation. Optional HTTP extensions are often expressed
2496 using request header fields.</p>
2498 <p>This directive gives the server administrator greater
2499 control over abnormal client request behavior, which may be
2500 useful for avoiding some forms of denial-of-service attacks.
2501 The value should be increased if normal clients see an error
2502 response from the server that indicates too many fields were
2503 sent in the request.</p>
2507 <pre class="prettyprint lang-config">LimitRequestFields 50</pre>
2510 <div class="warning"><h3>Warning</h3>
2511 <p> When name-based virtual hosting is used, the value for this
2512 directive is taken from the default (first-listed) virtual host for the
2513 local IP and port combination.</p>
2518 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2519 <div class="directive-section"><h2><a name="LimitRequestFieldSize" id="LimitRequestFieldSize">LimitRequestFieldSize</a> <a name="limitrequestfieldsize" id="limitrequestfieldsize">Directive</a></h2>
2520 <table class="directive">
2521 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of the HTTP request header allowed from the
2523 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFieldSize <var>bytes</var></code></td></tr>
2524 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFieldSize 8190</code></td></tr>
2525 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2526 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2527 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2529 <p>This directive specifies the number of <var>bytes</var>
2530 that will be allowed in an HTTP request header.</p>
2532 <p>The <code class="directive">LimitRequestFieldSize</code> directive
2533 allows the server administrator to set the limit
2534 on the allowed size of an HTTP request header field. A server
2535 needs this value to be large enough to hold any one header field
2536 from a normal client request. The size of a normal request header
2537 field will vary greatly among different client implementations,
2538 often depending upon the extent to which a user has configured
2539 their browser to support detailed content negotiation. SPNEGO
2540 authentication headers can be up to 12392 bytes.</p>
2542 <p>This directive gives the server administrator greater
2543 control over abnormal client request behavior, which may be
2544 useful for avoiding some forms of denial-of-service attacks.</p>
2548 <pre class="prettyprint lang-config">LimitRequestFieldSize 4094</pre>
2551 <div class="note">Under normal conditions, the value should not be changed from
2554 <div class="warning"><h3>Warning</h3>
2555 <p> When name-based virtual hosting is used, the value for this
2556 directive is taken from the default (first-listed) virtual host best
2557 matching the current IP address and port combination.</p>
2561 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2562 <div class="directive-section"><h2><a name="LimitRequestLine" id="LimitRequestLine">LimitRequestLine</a> <a name="limitrequestline" id="limitrequestline">Directive</a></h2>
2563 <table class="directive">
2564 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limit the size of the HTTP request line that will be accepted
2565 from the client</td></tr>
2566 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestLine <var>bytes</var></code></td></tr>
2567 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestLine 8190</code></td></tr>
2568 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2569 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2570 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2572 <p>This directive sets the number of <var>bytes</var> that will be
2573 allowed on the HTTP request-line.</p>
2575 <p>The <code class="directive">LimitRequestLine</code> directive allows
2576 the server administrator to set the limit on the allowed size
2577 of a client's HTTP request-line. Since the request-line consists of the
2578 HTTP method, URI, and protocol version, the
2579 <code class="directive">LimitRequestLine</code> directive places a
2580 restriction on the length of a request-URI allowed for a request
2581 on the server. A server needs this value to be large enough to
2582 hold any of its resource names, including any information that
2583 might be passed in the query part of a <code>GET</code> request.</p>
2585 <p>This directive gives the server administrator greater
2586 control over abnormal client request behavior, which may be
2587 useful for avoiding some forms of denial-of-service attacks.</p>
2591 <pre class="prettyprint lang-config">LimitRequestLine 4094</pre>
2594 <div class="note">Under normal conditions, the value should not be changed from
2595 the default. Also, you can't set this higher than 8190 without
2596 modifying the source and rebuilding.</div>
2598 <div class="warning"><h3>Warning</h3>
2599 <p> When name-based virtual hosting is used, the value for this
2600 directive is taken from the default (first-listed) virtual host best
2601 matching the current IP address and port combination.</p>
2606 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2607 <div class="directive-section"><h2><a name="LimitXMLRequestBody" id="LimitXMLRequestBody">LimitXMLRequestBody</a> <a name="limitxmlrequestbody" id="limitxmlrequestbody">Directive</a></h2>
2608 <table class="directive">
2609 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of an XML-based request body</td></tr>
2610 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitXMLRequestBody <var>bytes</var></code></td></tr>
2611 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitXMLRequestBody 1000000</code></td></tr>
2612 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2613 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2614 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2615 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2617 <p>Limit (in bytes) on maximum size of an XML-based request
2618 body. A value of <code>0</code> will disable any checking.</p>
2622 <pre class="prettyprint lang-config">LimitXMLRequestBody 0</pre>
2627 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2628 <div class="directive-section"><h2><a name="Location" id="Location"><Location></a> <a name="location" id="location">Directive</a></h2>
2629 <table class="directive">
2630 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to matching
2632 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Location
2633 <var>URL-path</var>|<var>URL</var>> ... </Location></code></td></tr>
2634 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2635 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2636 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2638 <p>The <code class="directive"><Location></code> directive
2639 limits the scope of the enclosed directives by URL. It is similar to the
2640 <code class="directive"><a href="#directory"><Directory></a></code>
2641 directive, and starts a subsection which is terminated with a
2642 <code></Location></code> directive. <code class="directive"><Location></code> sections are processed in the
2643 order they appear in the configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
2644 <code>.htaccess</code> files are read, and after the <code class="directive"><a href="#files"><Files></a></code> sections.</p>
2646 <p><code class="directive"><Location></code> sections operate
2647 completely outside the filesystem. This has several consequences.
2648 Most importantly, <code class="directive"><Location></code>
2649 directives should not be used to control access to filesystem
2650 locations. Since several different URLs may map to the same
2651 filesystem location, such access controls may by circumvented.</p>
2653 <p>The enclosed directives will be applied to the request if the path component
2654 of the URL meets <em>any</em> of the following criteria:
2657 <li>The specified location matches exactly the path component of the URL.
2659 <li>The specified location, which ends in a forward slash, is a prefix
2660 of the path component of the URL (treated as a context root).
2662 <li>The specified location, with the addition of a trailing slash, is a
2663 prefix of the path component of the URL (also treated as a context root).
2667 In the example below, where no trailing slash is used, requests to
2668 /private1, /private1/ and /private1/file.txt will have the enclosed
2669 directives applied, but /private1other would not.
2671 <pre class="prettyprint lang-config">
2672 <Location /private1>
2678 In the example below, where a trailing slash is used, requests to
2679 /private2/ and /private2/file.txt will have the enclosed
2680 directives applied, but /private2 and /private2other would not.
2682 <pre class="prettyprint lang-config">
2683 <Location /private2<em>/</em>>
2689 <div class="note"><h3>When to use <code class="directive"><Location></code></h3>
2691 <p>Use <code class="directive"><Location></code> to apply
2692 directives to content that lives outside the filesystem. For
2693 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
2694 <code><Location /></code>, which is an easy way to
2695 apply a configuration to the entire server.</p>
2698 <p>For all origin (non-proxy) requests, the URL to be matched is a
2699 URL-path of the form <code>/path/</code>. <em>No scheme, hostname,
2700 port, or query string may be included.</em> For proxy requests, the
2701 URL to be matched is of the form
2702 <code>scheme://servername/path</code>, and you must include the
2705 <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
2706 any single character, and <code>*</code> matches any sequences of
2707 characters. Neither wildcard character matches a / in the URL-path.</p>
2709 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
2710 can also be used, with the addition of the <code>~</code>
2711 character. For example:</p>
2713 <pre class="prettyprint lang-config">
2714 <Location ~ "/(extra|special)/data">
2720 <p>would match URLs that contained the substring <code>/extra/data</code>
2721 or <code>/special/data</code>. The directive <code class="directive"><a href="#locationmatch"><LocationMatch></a></code> behaves
2722 identical to the regex version of <code class="directive"><Location></code>, and is preferred, for the
2723 simple reason that <code>~</code> is hard to distinguish from
2724 <code>-</code> in many fonts.</p>
2726 <p>The <code class="directive"><Location></code>
2727 functionality is especially useful when combined with the
2728 <code class="directive"><a href="#sethandler">SetHandler</a></code>
2729 directive. For example, to enable status requests, but allow them
2730 only from browsers at <code>example.com</code>, you might use:</p>
2732 <pre class="prettyprint lang-config">
2733 <Location /status>
2734 SetHandler server-status
2735 Require host example.com
2740 <div class="note"><h3>Note about / (slash)</h3>
2741 <p>The slash character has special meaning depending on where in a
2742 URL it appears. People may be used to its behavior in the filesystem
2743 where multiple adjacent slashes are frequently collapsed to a single
2744 slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
2745 <code>/home/foo</code>). In URL-space this is not necessarily true.
2746 The <code class="directive"><a href="#locationmatch"><LocationMatch></a></code>
2747 directive and the regex version of <code class="directive"><Location></code> require you to explicitly specify multiple
2748 slashes if that is your intention.</p>
2750 <p>For example, <code><LocationMatch ^/abc></code> would match
2751 the request URL <code>/abc</code> but not the request URL <code>
2752 //abc</code>. The (non-regex) <code class="directive"><Location></code> directive behaves similarly when used for
2753 proxy requests. But when (non-regex) <code class="directive"><Location></code> is used for non-proxy requests it will
2754 implicitly match multiple slashes with a single slash. For example,
2755 if you specify <code><Location /abc/def></code> and the
2756 request is to <code>/abc//def</code> then it will match.</p>
2761 <li><a href="../sections.html">How <Directory>, <Location>
2762 and <Files> sections work</a> for an explanation of how these
2763 different sections are combined when a request is received.</li>
2764 <li><code class="directive"><a href="#locationmatch">LocationMatch</a></code></li>
2767 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2768 <div class="directive-section"><h2><a name="LocationMatch" id="LocationMatch"><LocationMatch></a> <a name="locationmatch" id="locationmatch">Directive</a></h2>
2769 <table class="directive">
2770 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to regular-expression
2771 matching URLs</td></tr>
2772 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LocationMatch
2773 <var>regex</var>> ... </LocationMatch></code></td></tr>
2774 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2775 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2776 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2778 <p>The <code class="directive"><LocationMatch></code> directive
2779 limits the scope of the enclosed directives by URL, in an identical manner
2780 to <code class="directive"><a href="#location"><Location></a></code>. However,
2781 it takes a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
2782 as an argument instead of a simple string. For example:</p>
2784 <pre class="prettyprint lang-config">
2785 <LocationMatch "/(extra|special)/data">
2787 </LocationMatch>
2791 <p>would match URLs that contained the substring <code>/extra/data</code>
2792 or <code>/special/data</code>.</p>
2794 <p>From 2.4.8 onwards, named groups and backreferences are captured and
2795 written to the environment with the corresponding name prefixed with
2796 "MATCH_" and in upper case. This allows elements of URLs to be referenced
2797 from within <a href="expr.html">expressions</a> and modules like
2798 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
2799 (unnamed) backreferences are ignored. Use named groups instead.</p>
2801 <pre class="prettyprint lang-config">
2802 <LocationMatch ^/combined/(?<sitename>[^/]+)>
2803 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
2804 </LocationMatch>
2810 <li><a href="../sections.html">How <Directory>, <Location>
2811 and <Files> sections work</a> for an explanation of how these
2812 different sections are combined when a request is received</li>
2815 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2816 <div class="directive-section"><h2><a name="LogLevel" id="LogLevel">LogLevel</a> <a name="loglevel" id="loglevel">Directive</a></h2>
2817 <table class="directive">
2818 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Controls the verbosity of the ErrorLog</td></tr>
2819 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel [<var>module</var>:]<var>level</var>
2820 [<var>module</var>:<var>level</var>] ...
2822 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LogLevel warn</code></td></tr>
2823 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2824 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2825 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2826 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Per-module and per-directory configuration is available in
2827 Apache HTTP Server 2.3.6 and later</td></tr>
2829 <p><code class="directive">LogLevel</code> adjusts the verbosity of the
2830 messages recorded in the error logs (see <code class="directive"><a href="#errorlog">ErrorLog</a></code> directive). The following
2831 <var>level</var>s are available, in order of decreasing
2834 <table class="bordered">
2837 <th><strong>Level</strong> </th>
2839 <th><strong>Description</strong> </th>
2841 <th><strong>Example</strong> </th>
2845 <td><code>emerg</code> </td>
2847 <td>Emergencies - system is unusable.</td>
2849 <td>"Child cannot open lock file. Exiting"</td>
2853 <td><code>alert</code> </td>
2855 <td>Action must be taken immediately.</td>
2857 <td>"getpwuid: couldn't determine user name from uid"</td>
2861 <td><code>crit</code> </td>
2863 <td>Critical Conditions.</td>
2865 <td>"socket: Failed to get a socket, exiting child"</td>
2869 <td><code>error</code> </td>
2871 <td>Error conditions.</td>
2873 <td>"Premature end of script headers"</td>
2877 <td><code>warn</code> </td>
2879 <td>Warning conditions.</td>
2881 <td>"child process 1234 did not exit, sending another
2886 <td><code>notice</code> </td>
2888 <td>Normal but significant condition.</td>
2890 <td>"httpd: caught SIGBUS, attempting to dump core in
2895 <td><code>info</code> </td>
2897 <td>Informational.</td>
2899 <td>"Server seems busy, (you may need to increase
2900 StartServers, or Min/MaxSpareServers)..."</td>
2904 <td><code>debug</code> </td>
2906 <td>Debug-level messages</td>
2908 <td>"Opening config file ..."</td>
2911 <td><code>trace1</code> </td>
2913 <td>Trace messages</td>
2915 <td>"proxy: FTP: control connection complete"</td>
2918 <td><code>trace2</code> </td>
2920 <td>Trace messages</td>
2922 <td>"proxy: CONNECT: sending the CONNECT request to the remote proxy"</td>
2925 <td><code>trace3</code> </td>
2927 <td>Trace messages</td>
2929 <td>"openssl: Handshake: start"</td>
2932 <td><code>trace4</code> </td>
2934 <td>Trace messages</td>
2936 <td>"read from buffered SSL brigade, mode 0, 17 bytes"</td>
2939 <td><code>trace5</code> </td>
2941 <td>Trace messages</td>
2943 <td>"map lookup FAILED: map=rewritemap key=keyname"</td>
2946 <td><code>trace6</code> </td>
2948 <td>Trace messages</td>
2950 <td>"cache lookup FAILED, forcing new map lookup"</td>
2953 <td><code>trace7</code> </td>
2955 <td>Trace messages, dumping large amounts of data</td>
2957 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2960 <td><code>trace8</code> </td>
2962 <td>Trace messages, dumping large amounts of data</td>
2964 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2968 <p>When a particular level is specified, messages from all
2969 other levels of higher significance will be reported as well.
2970 <em>E.g.</em>, when <code>LogLevel info</code> is specified,
2971 then messages with log levels of <code>notice</code> and
2972 <code>warn</code> will also be posted.</p>
2974 <p>Using a level of at least <code>crit</code> is
2979 <pre class="prettyprint lang-config">LogLevel notice</pre>
2982 <div class="note"><h3>Note</h3>
2983 <p>When logging to a regular file messages of the level
2984 <code>notice</code> cannot be suppressed and thus are always
2985 logged. However, this doesn't apply when logging is done
2986 using <code>syslog</code>.</p>
2989 <p>Specifying a level without a module name will reset the level
2990 for all modules to that level. Specifying a level with a module
2991 name will set the level for that module only. It is possible to
2992 use the module source file name, the module identifier, or the
2993 module identifier with the trailing <code>_module</code> omitted
2994 as module specification. This means the following three specifications
2997 <pre class="prettyprint lang-config">
2998 LogLevel info ssl:warn
2999 LogLevel info mod_ssl.c:warn
3000 LogLevel info ssl_module:warn
3004 <p>It is also possible to change the level per directory:</p>
3006 <pre class="prettyprint lang-config">
3008 <Directory "/usr/local/apache/htdocs/app">
3015 Per directory loglevel configuration only affects messages that are
3016 logged after the request has been parsed and that are associated with
3017 the request. Log messages which are associated with the server or
3018 the connection are not affected. The latter can be influenced by the
3019 <code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code> directive,
3025 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
3026 <li><code class="directive"><a href="#errorlogformat">ErrorLogFormat</a></code></li>
3027 <li><code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code></li>
3028 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
3031 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3032 <div class="directive-section"><h2><a name="LogLevelOverride" id="LogLevelOverride">LogLevelOverride</a> <a name="logleveloverride" id="logleveloverride">Directive</a></h2>
3033 <table class="directive">
3034 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Override the verbosity of the ErrorLog for certain clients</td></tr>
3035 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel <var>ipaddress</var>[/<var>prefixlen</var>]
3036 [<var>module</var>:]<var>level</var> [<var>module</var>:<var>level</var>] ...
3038 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>unset</code></td></tr>
3039 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3040 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3041 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3042 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.5.0 and later</td></tr>
3044 <p><code class="directive">LogLevelOverride</code> adjusts the
3045 <code class="directive"><a href="#loglevel">LogLevel</a></code> for requests coming from
3046 certain client IP addresses.
3047 This allows to enable verbose logging only for certain test clients.
3048 The IP address is checked at a very early state in the connection
3049 processing. Therefore, <code class="directive">LogLevelOverride</code> allows to
3050 change the log level for things like the SSL handshake which happen before
3051 a <code class="directive"><a href="#loglevel">LogLevel</a></code> directive in an
3052 <code class="directive"><a href="#if"><If></a></code> container would
3055 <p><code class="directive">LogLevelOverride</code> accepts either a single
3056 IP-address or a CIDR IP-address/len subnet specification.
3057 For the syntax of the loglevel specification, see the
3058 <code class="directive"><a href="#loglevel">LogLevel</a></code> directive.</p>
3060 <p>For requests that match a <code class="directive">LogLevelOverride</code>
3061 directive, per-directory specifications of
3062 <code class="directive"><a href="#loglevel">LogLevel</a></code> are ignored.</p>
3066 <pre class="prettyprint lang-config">
3067 LogLevelOverride 192.0.2.0/24 ssl:trace6
3068 LogLevelOverride 192.0.2.7 ssl:trace8
3073 <code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code> only affects
3074 log messages that are associated with the request or the connection.
3075 Log messages which are associated with the server not affected.
3081 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
3084 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3085 <div class="directive-section"><h2><a name="MaxKeepAliveRequests" id="MaxKeepAliveRequests">MaxKeepAliveRequests</a> <a name="maxkeepaliverequests" id="maxkeepaliverequests">Directive</a></h2>
3086 <table class="directive">
3087 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of requests allowed on a persistent
3088 connection</td></tr>
3089 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxKeepAliveRequests <var>number</var></code></td></tr>
3090 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxKeepAliveRequests 100</code></td></tr>
3091 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3092 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3093 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3095 <p>The <code class="directive">MaxKeepAliveRequests</code> directive
3096 limits the number of requests allowed per connection when
3097 <code class="directive"><a href="#keepalive">KeepAlive</a></code> is on. If it is
3098 set to <code>0</code>, unlimited requests will be allowed. We
3099 recommend that this setting be kept to a high value for maximum
3100 server performance.</p>
3104 <pre class="prettyprint lang-config">MaxKeepAliveRequests 500</pre>
3108 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3109 <div class="directive-section"><h2><a name="MaxRangeOverlaps" id="MaxRangeOverlaps">MaxRangeOverlaps</a> <a name="maxrangeoverlaps" id="maxrangeoverlaps">Directive</a></h2>
3110 <table class="directive">
3111 <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
3113 <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>
3114 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeOverlaps 20</code></td></tr>
3115 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3116 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3117 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3118 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3120 <p>The <code class="directive">MaxRangeOverlaps</code> directive
3121 limits the number of overlapping HTTP ranges the server is willing to
3122 return to the client. If more overlapping ranges than permitted are requested,
3123 the complete resource is returned instead.</p>
3126 <dt><strong>default</strong></dt>
3127 <dd>Limits the number of overlapping ranges to a compile-time default of 20.</dd>
3129 <dt><strong>none</strong></dt>
3130 <dd>No overlapping Range headers are allowed.</dd>
3132 <dt><strong>unlimited</strong></dt>
3133 <dd>The server does not limit the number of overlapping ranges it is
3134 willing to satisfy.</dd>
3136 <dt><var>number-of-ranges</var></dt>
3137 <dd>A positive number representing the maximum number of overlapping ranges the
3138 server is willing to satisfy.</dd>
3142 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3143 <div class="directive-section"><h2><a name="MaxRangeReversals" id="MaxRangeReversals">MaxRangeReversals</a> <a name="maxrangereversals" id="maxrangereversals">Directive</a></h2>
3144 <table class="directive">
3145 <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
3147 <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>
3148 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeReversals 20</code></td></tr>
3149 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3150 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3151 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3152 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3154 <p>The <code class="directive">MaxRangeReversals</code> directive
3155 limits the number of HTTP Range reversals the server is willing to
3156 return to the client. If more ranges reversals than permitted are requested,
3157 the complete resource is returned instead.</p>
3160 <dt><strong>default</strong></dt>
3161 <dd>Limits the number of range reversals to a compile-time default of 20.</dd>
3163 <dt><strong>none</strong></dt>
3164 <dd>No Range reversals headers are allowed.</dd>
3166 <dt><strong>unlimited</strong></dt>
3167 <dd>The server does not limit the number of range reversals it is
3168 willing to satisfy.</dd>
3170 <dt><var>number-of-ranges</var></dt>
3171 <dd>A positive number representing the maximum number of range reversals the
3172 server is willing to satisfy.</dd>
3176 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3177 <div class="directive-section"><h2><a name="MaxRanges" id="MaxRanges">MaxRanges</a> <a name="maxranges" id="maxranges">Directive</a></h2>
3178 <table class="directive">
3179 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of ranges allowed before returning the complete
3181 <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>
3182 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRanges 200</code></td></tr>
3183 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3184 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3185 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3186 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3188 <p>The <code class="directive">MaxRanges</code> directive
3189 limits the number of HTTP ranges the server is willing to
3190 return to the client. If more ranges than permitted are requested,
3191 the complete resource is returned instead.</p>
3194 <dt><strong>default</strong></dt>
3195 <dd>Limits the number of ranges to a compile-time default of 200.</dd>
3197 <dt><strong>none</strong></dt>
3198 <dd>Range headers are ignored.</dd>
3200 <dt><strong>unlimited</strong></dt>
3201 <dd>The server does not limit the number of ranges it is
3202 willing to satisfy.</dd>
3204 <dt><var>number-of-ranges</var></dt>
3205 <dd>A positive number representing the maximum number of ranges the
3206 server is willing to satisfy.</dd>
3210 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3211 <div class="directive-section"><h2><a name="Mutex" id="Mutex">Mutex</a> <a name="mutex" id="mutex">Directive</a></h2>
3212 <table class="directive">
3213 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures mutex mechanism and lock file directory for all
3214 or specified mutexes</td></tr>
3215 <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>
3216 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Mutex default</code></td></tr>
3217 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3218 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3219 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3220 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.4 and later</td></tr>
3222 <p>The <code class="directive">Mutex</code> directive sets the mechanism,
3223 and optionally the lock file location, that httpd and modules use
3224 to serialize access to resources. Specify <code>default</code> as
3225 the first argument to change the settings for all mutexes; specify
3226 a mutex name (see table below) as the first argument to override
3227 defaults only for that mutex.</p>
3229 <p>The <code class="directive">Mutex</code> directive is typically used in
3230 the following exceptional situations:</p>
3233 <li>change the mutex mechanism when the default mechanism selected
3234 by <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> has a functional or performance
3237 <li>change the directory used by file-based mutexes when the
3238 default directory does not support locking</li>
3241 <div class="note"><h3>Supported modules</h3>
3242 <p>This directive only configures mutexes which have been registered
3243 with the core server using the <code>ap_mutex_register()</code> API.
3244 All modules bundled with httpd support the <code class="directive">Mutex</code>
3245 directive, but third-party modules may not. Consult the documentation
3246 of the third-party module, which must indicate the mutex name(s) which
3247 can be configured if this directive is supported.</p>
3250 <p>The following mutex <em>mechanisms</em> are available:</p>
3252 <li><code>default | yes</code>
3253 <p>This selects the default locking implementation, as determined by
3254 <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a>. The default locking implementation can
3255 be displayed by running <code class="program"><a href="../programs/httpd.html">httpd</a></code> with the
3256 <code>-V</code> option.</p></li>
3258 <li><code>none | no</code>
3259 <p>This effectively disables the mutex, and is only allowed for a
3260 mutex if the module indicates that it is a valid choice. Consult the
3261 module documentation for more information.</p></li>
3263 <li><code>posixsem</code>
3264 <p>This is a mutex variant based on a Posix semaphore.</p>
3266 <div class="warning"><h3>Warning</h3>
3267 <p>The semaphore ownership is not recovered if a thread in the process
3268 holding the mutex segfaults, resulting in a hang of the web server.</p>
3272 <li><code>sysvsem</code>
3273 <p>This is a mutex variant based on a SystemV IPC semaphore.</p>
3275 <div class="warning"><h3>Warning</h3>
3276 <p>It is possible to "leak" SysV semaphores if processes crash
3277 before the semaphore is removed.</p>
3280 <div class="warning"><h3>Security</h3>
3281 <p>The semaphore API allows for a denial of service attack by any
3282 CGIs running under the same uid as the webserver (<em>i.e.</em>,
3283 all CGIs, unless you use something like <code class="program"><a href="../programs/suexec.html">suexec</a></code>
3284 or <code>cgiwrapper</code>).</p>
3288 <li><code>sem</code>
3289 <p>This selects the "best" available semaphore implementation, choosing
3290 between Posix and SystemV IPC semaphores, in that order.</p></li>
3292 <li><code>pthread</code>
3293 <p>This is a mutex variant based on cross-process Posix thread
3296 <div class="warning"><h3>Warning</h3>
3297 <p>On most systems, if a child process terminates abnormally while
3298 holding a mutex that uses this implementation, the server will deadlock
3299 and stop responding to requests. When this occurs, the server will
3300 require a manual restart to recover.</p>
3301 <p>Solaris is a notable exception as it provides a mechanism which
3302 usually allows the mutex to be recovered after a child process
3303 terminates abnormally while holding a mutex.</p>
3304 <p>If your system implements the
3305 <code>pthread_mutexattr_setrobust_np()</code> function, you may be able
3306 to use the <code>pthread</code> option safely.</p>
3310 <li><code>fcntl:/path/to/mutex</code>
3311 <p>This is a mutex variant where a physical (lock-)file and the
3312 <code>fcntl()</code> function are used as the mutex.</p>
3314 <div class="warning"><h3>Warning</h3>
3315 <p>When multiple mutexes based on this mechanism are used within
3316 multi-threaded, multi-process environments, deadlock errors (EDEADLK)
3317 can be reported for valid mutex operations if <code>fcntl()</code>
3318 is not thread-aware, such as on Solaris.</p>
3322 <li><code>flock:/path/to/mutex</code>
3323 <p>This is similar to the <code>fcntl:/path/to/mutex</code> method
3324 with the exception that the <code>flock()</code> function is used to
3325 provide file locking.</p></li>
3327 <li><code>file:/path/to/mutex</code>
3328 <p>This selects the "best" available file locking implementation,
3329 choosing between <code>fcntl</code> and <code>flock</code>, in that
3333 <p>Most mechanisms are only available on selected platforms, where the
3334 underlying platform and <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> support it. Mechanisms
3335 which aren't available on all platforms are <em>posixsem</em>,
3336 <em>sysvsem</em>, <em>sem</em>, <em>pthread</em>, <em>fcntl</em>,
3337 <em>flock</em>, and <em>file</em>.</p>
3339 <p>With the file-based mechanisms <em>fcntl</em> and <em>flock</em>,
3340 the path, if provided, is a directory where the lock file will be created.
3341 The default directory is httpd's run-time file directory,
3342 <code class="directive"><a href="#defaultruntimedir">DefaultRuntimeDir</a></code>. If a relative
3343 path is provided, it is relative to
3344 <code class="directive"><a href="#defaultruntimedir">DefaultRuntimeDir</a></code>. Always use a local
3345 disk filesystem for <code>/path/to/mutex</code> and never a directory residing
3346 on a NFS- or AFS-filesystem. The basename of the file will be the mutex
3347 type, an optional instance string provided by the module, and unless the
3348 <code>OmitPID</code> keyword is specified, the process id of the httpd
3349 parent process will be appended to to make the file name unique, avoiding
3350 conflicts when multiple httpd instances share a lock file directory. For
3351 example, if the mutex name is <code>mpm-accept</code> and the lock file
3352 directory is <code>/var/httpd/locks</code>, the lock file name for the
3353 httpd instance with parent process id 12345 would be
3354 <code>/var/httpd/locks/mpm-accept.12345</code>.</p>
3356 <div class="warning"><h3>Security</h3>
3357 <p>It is best to <em>avoid</em> putting mutex files in a world-writable
3358 directory such as <code>/var/tmp</code> because someone could create
3359 a denial of service attack and prevent the server from starting by
3360 creating a lockfile with the same name as the one the server will try
3364 <p>The following table documents the names of mutexes used by httpd
3365 and bundled modules.</p>
3367 <table class="bordered"><tr class="header">
3370 <th>Protected resource</th>
3373 <td><code>mpm-accept</code></td>
3374 <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>
3375 <td>incoming connections, to avoid the thundering herd problem;
3376 for more information, refer to the
3377 <a href="../misc/perf-tuning.html">performance tuning</a>
3381 <td><code>authdigest-client</code></td>
3382 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3383 <td>client list in shared memory</td>
3386 <td><code>authdigest-opaque</code></td>
3387 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3388 <td>counter in shared memory</td>
3391 <td><code>ldap-cache</code></td>
3392 <td><code class="module"><a href="../mod/mod_ldap.html">mod_ldap</a></code></td>
3393 <td>LDAP result cache</td>
3396 <td><code>rewrite-map</code></td>
3397 <td><code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code></td>
3398 <td>communication with external mapping programs, to avoid
3399 intermixed I/O from multiple requests</td>
3402 <td><code>ssl-cache</code></td>
3403 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3404 <td>SSL session cache</td>
3407 <td><code>ssl-stapling</code></td>
3408 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3409 <td>OCSP stapling response cache</td>
3412 <td><code>watchdog-callback</code></td>
3413 <td><code class="module"><a href="../mod/mod_watchdog.html">mod_watchdog</a></code></td>
3414 <td>callback function of a particular client module</td>
3418 <p>The <code>OmitPID</code> keyword suppresses the addition of the httpd
3419 parent process id from the lock file name.</p>
3421 <p>In the following example, the mutex mechanism for the MPM accept
3422 mutex will be changed from the compiled-in default to <code>fcntl</code>,
3423 with the associated lock file created in directory
3424 <code>/var/httpd/locks</code>. The mutex mechanism for all other mutexes
3425 will be changed from the compiled-in default to <code>sysvsem</code>.</p>
3427 <pre class="prettyprint lang-config">
3428 Mutex sysvsem default
3429 Mutex fcntl:/var/httpd/locks mpm-accept
3434 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3435 <div class="directive-section"><h2><a name="NameVirtualHost" id="NameVirtualHost">NameVirtualHost</a> <a name="namevirtualhost" id="namevirtualhost">Directive</a></h2>
3436 <table class="directive">
3437 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>DEPRECATED: Designates an IP address for name-virtual
3439 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NameVirtualHost <var>addr</var>[:<var>port</var>]</code></td></tr>
3440 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3441 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3442 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3445 <p>Prior to 2.3.11, <code class="directive">NameVirtualHost</code> was required
3446 to instruct the server that a particular IP address and port combination
3447 was usable as a name-based virtual host. In 2.3.11 and later,
3448 any time an IP address and port combination is used in multiple virtual
3449 hosts, name-based virtual hosting is automatically enabled for that address.</p>
3451 <p>This directive currently has no effect.</p>
3455 <li><a href="../vhosts/">Virtual Hosts
3456 documentation</a></li>
3459 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3460 <div class="directive-section"><h2><a name="Options" id="Options">Options</a> <a name="options" id="options">Directive</a></h2>
3461 <table class="directive">
3462 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures what features are available in a particular
3464 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Options
3465 [+|-]<var>option</var> [[+|-]<var>option</var>] ...</code></td></tr>
3466 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Options FollowSymlinks</code></td></tr>
3467 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3468 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
3469 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3470 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3471 <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>
3473 <p>The <code class="directive">Options</code> directive controls which
3474 server features are available in a particular directory.</p>
3476 <p><var>option</var> can be set to <code>None</code>, in which
3477 case none of the extra features are enabled, or one or more of
3481 <dt><code>All</code></dt>
3483 <dd>All options except for <code>MultiViews</code>.</dd>
3485 <dt><code>ExecCGI</code></dt>
3488 Execution of CGI scripts using <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>
3491 <dt><code>FollowSymLinks</code></dt>
3494 The server will follow symbolic links in this directory. This is
3495 the default setting.
3497 <p>Even though the server follows the symlink it does <em>not</em>
3498 change the pathname used to match against <code class="directive"><a href="#directory"><Directory></a></code> sections.</p>
3500 <p>The <code>FollowSymLinks</code> and
3501 <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
3502 <code>.htaccess</code> files.</p>
3504 <p>Omitting this option should not be considered a security restriction,
3505 since symlink testing is subject to race conditions that make it
3509 <dt><code>Includes</code></dt>
3512 Server-side includes provided by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
3515 <dt><code>IncludesNOEXEC</code></dt>
3519 Server-side includes are permitted, but the <code>#exec
3520 cmd</code> and <code>#exec cgi</code> are disabled. It is still
3521 possible to <code>#include virtual</code> CGI scripts from
3522 <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>ed
3525 <dt><code>Indexes</code></dt>
3528 If a URL which maps to a directory is requested, and there
3529 is no <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
3530 (<em>e.g.</em>, <code>index.html</code>) in that directory, then
3531 <code class="module"><a href="../mod/mod_autoindex.html">mod_autoindex</a></code> will return a formatted listing
3532 of the directory.</dd>
3534 <dt><code>MultiViews</code></dt>
3537 <a href="../content-negotiation.html">Content negotiated</a>
3538 "MultiViews" are allowed using
3539 <code class="module"><a href="../mod/mod_negotiation.html">mod_negotiation</a></code>.
3540 <div class="note"><h3>Note</h3> <p>This option gets ignored if set
3541 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>
3542 needs real resources to compare against and evaluate from.</p></div>
3545 <dt><code>SymLinksIfOwnerMatch</code></dt>
3547 <dd>The server will only follow symbolic links for which the
3548 target file or directory is owned by the same user id as the
3551 <div class="note"><h3>Note</h3>
3552 <p>The <code>FollowSymLinks</code> and
3553 <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
3554 <code>.htaccess</code> files.</p>
3556 <p>This option should not be considered a security restriction,
3557 since symlink testing is subject to race conditions that make it
3562 <p>Normally, if multiple <code class="directive">Options</code> could
3563 apply to a directory, then the most specific one is used and
3564 others are ignored; the options are not merged. (See <a href="../sections.html#mergin">how sections are merged</a>.)
3565 However if <em>all</em> the options on the
3566 <code class="directive">Options</code> directive are preceded by a
3567 <code>+</code> or <code>-</code> symbol, the options are
3568 merged. Any options preceded by a <code>+</code> are added to the
3569 options currently in force, and any options preceded by a
3570 <code>-</code> are removed from the options currently in
3573 <div class="note"><h3>Note</h3>
3574 <p>Mixing <code class="directive">Options</code> with a <code>+</code> or
3575 <code>-</code> with those without is not valid syntax, and will be
3576 rejected during server startup by the syntax check with an abort.</p>
3579 <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>
3581 <pre class="prettyprint lang-config">
3582 <Directory "/web/docs">
3583 Options Indexes FollowSymLinks
3586 <Directory "/web/docs/spec">
3592 <p>then only <code>Includes</code> will be set for the
3593 <code>/web/docs/spec</code> directory. However if the second
3594 <code class="directive">Options</code> directive uses the <code>+</code> and
3595 <code>-</code> symbols:</p>
3597 <pre class="prettyprint lang-config">
3598 <Directory "/web/docs">
3599 Options Indexes FollowSymLinks
3602 <Directory "/web/docs/spec">
3603 Options +Includes -Indexes
3608 <p>then the options <code>FollowSymLinks</code> and
3609 <code>Includes</code> are set for the <code>/web/docs/spec</code>
3612 <div class="note"><h3>Note</h3>
3613 <p>Using <code>-IncludesNOEXEC</code> or
3614 <code>-Includes</code> disables server-side includes completely
3615 regardless of the previous setting.</p>
3618 <p>The default in the absence of any other settings is
3619 <code>FollowSymlinks</code>.</p>
3622 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3623 <div class="directive-section"><h2><a name="Protocol" id="Protocol">Protocol</a> <a name="protocol" id="protocol">Directive</a></h2>
3624 <table class="directive">
3625 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Protocol for a listening socket</td></tr>
3626 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Protocol <var>protocol</var></code></td></tr>
3627 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3628 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3629 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3630 <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>
3632 <p>This directive specifies the protocol used for a specific listening socket.
3633 The protocol is used to determine which module should handle a request, and
3634 to apply protocol specific optimizations with the <code class="directive">AcceptFilter</code>
3637 <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>
3639 <p>For example, if you are running <code>https</code> on a non-standard port, specify the protocol explicitly:</p>
3641 <pre class="prettyprint lang-config">Protocol https</pre>
3644 <p>You can also specify the protocol using the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code> directive.</p>
3648 <li><code class="directive"><a href="#acceptfilter">AcceptFilter</a></code></li>
3649 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
3652 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3653 <div class="directive-section"><h2><a name="RegisterHttpMethod" id="RegisterHttpMethod">RegisterHttpMethod</a> <a name="registerhttpmethod" id="registerhttpmethod">Directive</a></h2>
3654 <table class="directive">
3655 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Register non-standard HTTP methods</td></tr>
3656 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>RegisterHttpMethod <var>method</var> [<var>method</var> [...]]</code></td></tr>
3657 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3658 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3659 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3661 <p>HTTP Methods that are not conforming to the relvant RFCs are normally
3662 rejected by request processing in Apache HTTPD. To avoid this, modules
3663 can register non-standard HTTP methods they support.
3664 The <code class="directive">RegisterHttpMethod</code> allows to register such
3665 methods manually. This can be useful for if such methods are forwared
3666 for external processing, e.g. to a CGI script.</p>
3669 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3670 <div class="directive-section"><h2><a name="RLimitCPU" id="RLimitCPU">RLimitCPU</a> <a name="rlimitcpu" id="rlimitcpu">Directive</a></h2>
3671 <table class="directive">
3672 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the CPU consumption of processes launched
3673 by Apache httpd children</td></tr>
3674 <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>
3675 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3676 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3677 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3678 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3679 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3681 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3682 resource limit for all processes and the second parameter sets
3683 the maximum resource limit. Either parameter can be a number,
3684 or <code>max</code> to indicate to the server that the limit should
3685 be set to the maximum allowed by the operating system
3686 configuration. Raising the maximum resource limit requires that
3687 the server is running as <code>root</code>, or in the initial startup
3690 <p>This applies to processes forked off from Apache httpd children
3691 servicing requests, not the Apache httpd children themselves. This
3692 includes CGI scripts and SSI exec commands, but not any
3693 processes forked off from the Apache httpd parent such as piped
3696 <p>CPU resource limits are expressed in seconds per
3701 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3702 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3705 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3706 <div class="directive-section"><h2><a name="RLimitMEM" id="RLimitMEM">RLimitMEM</a> <a name="rlimitmem" id="rlimitmem">Directive</a></h2>
3707 <table class="directive">
3708 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the memory consumption of processes launched
3709 by Apache httpd children</td></tr>
3710 <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>
3711 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3712 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3713 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3714 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3715 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3717 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3718 resource limit for all processes and the second parameter sets
3719 the maximum resource limit. Either parameter can be a number,
3720 or <code>max</code> to indicate to the server that the limit should
3721 be set to the maximum allowed by the operating system
3722 configuration. Raising the maximum resource limit requires that
3723 the server is running as <code>root</code>, or in the initial startup
3726 <p>This applies to processes forked off from Apache httpd children
3727 servicing requests, not the Apache httpd children themselves. This
3728 includes CGI scripts and SSI exec commands, but not any
3729 processes forked off from the Apache httpd parent such as piped
3732 <p>Memory resource limits are expressed in bytes per
3737 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3738 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3741 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3742 <div class="directive-section"><h2><a name="RLimitNPROC" id="RLimitNPROC">RLimitNPROC</a> <a name="rlimitnproc" id="rlimitnproc">Directive</a></h2>
3743 <table class="directive">
3744 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of processes that can be launched by
3745 processes launched by Apache httpd children</td></tr>
3746 <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>
3747 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3748 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3749 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3750 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3751 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3753 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3754 resource limit for all processes and the second parameter sets
3755 the maximum resource limit. Either parameter can be a number,
3756 or <code>max</code> to indicate to the server that the limit
3757 should be set to the maximum allowed by the operating system
3758 configuration. Raising the maximum resource limit requires that
3759 the server is running as <code>root</code>, or in the initial startup
3762 <p>This applies to processes forked off from Apache httpd children
3763 servicing requests, not the Apache httpd children themselves. This
3764 includes CGI scripts and SSI exec commands, but not any
3765 processes forked off from the Apache httpd parent such as piped
3768 <p>Process limits control the number of processes per user.</p>
3770 <div class="note"><h3>Note</h3>
3771 <p>If CGI processes are <strong>not</strong> running
3772 under user ids other than the web server user id, this directive
3773 will limit the number of processes that the server itself can
3774 create. Evidence of this situation will be indicated by
3775 <strong><code>cannot fork</code></strong> messages in the
3776 <code>error_log</code>.</p>
3781 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3782 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3785 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3786 <div class="directive-section"><h2><a name="ScriptInterpreterSource" id="ScriptInterpreterSource">ScriptInterpreterSource</a> <a name="scriptinterpretersource" id="scriptinterpretersource">Directive</a></h2>
3787 <table class="directive">
3788 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
3790 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ScriptInterpreterSource Registry|Registry-Strict|Script</code></td></tr>
3791 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ScriptInterpreterSource Script</code></td></tr>
3792 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3793 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3794 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3795 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3796 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Win32 only.</td></tr>
3798 <p>This directive is used to control how Apache httpd finds the
3799 interpreter used to run CGI scripts. The default setting is
3800 <code>Script</code>. This causes Apache httpd to use the interpreter pointed to
3801 by the shebang line (first line, starting with <code>#!</code>) in the
3802 script. On Win32 systems this line usually looks like:</p>
3804 <pre class="prettyprint lang-perl">#!C:/Perl/bin/perl.exe</pre>
3807 <p>or, if <code>perl</code> is in the <code>PATH</code>, simply:</p>
3809 <pre class="prettyprint lang-perl">#!perl</pre>
3812 <p>Setting <code>ScriptInterpreterSource Registry</code> will
3813 cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
3814 searched using the script file extension (e.g., <code>.pl</code>) as a
3815 search key. The command defined by the registry subkey
3816 <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
3817 <code>Shell\Open\Command</code> is used to open the script file. If the
3818 registry keys cannot be found, Apache httpd falls back to the behavior of the
3819 <code>Script</code> option.</p>
3821 <div class="warning"><h3>Security</h3>
3822 <p>Be careful when using <code>ScriptInterpreterSource
3823 Registry</code> with <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>'ed directories, because
3824 Apache httpd will try to execute <strong>every</strong> file within this
3825 directory. The <code>Registry</code> setting may cause undesired
3826 program calls on files which are typically not executed. For
3827 example, the default open command on <code>.htm</code> files on
3828 most Windows systems will execute Microsoft Internet Explorer, so
3829 any HTTP request for an <code>.htm</code> file existing within the
3830 script directory would start the browser in the background on the
3831 server. This is a good way to crash your system within a minute or
3835 <p>The option <code>Registry-Strict</code> which is new in Apache HTTP Server
3836 2.0 does the same thing as <code>Registry</code> but uses only the
3837 subkey <code>Shell\ExecCGI\Command</code>. The
3838 <code>ExecCGI</code> key is not a common one. It must be
3839 configured manually in the windows registry and hence prevents
3840 accidental program calls on your system.</p>
3843 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3844 <div class="directive-section"><h2><a name="SeeRequestTail" id="SeeRequestTail">SeeRequestTail</a> <a name="seerequesttail" id="seerequesttail">Directive</a></h2>
3845 <table class="directive">
3846 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine if mod_status displays the first 63 characters
3847 of a request or the last 63, assuming the request itself is greater than
3849 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SeeRequestTail On|Off</code></td></tr>
3850 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SeeRequestTail Off</code></td></tr>
3851 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3852 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3853 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3855 <p>mod_status with <code>ExtendedStatus On</code>
3856 displays the actual request being handled.
3857 For historical purposes, only 63 characters of the request
3858 are actually stored for display purposes. This directive
3859 controls whether the 1st 63 characters are stored (the previous
3860 behavior and the default) or if the last 63 characters are. This
3861 is only applicable, of course, if the length of the request is
3862 64 characters or greater.</p>
3864 <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:
3867 <table class="bordered">
3869 <th>Off (default)</th>
3870 <td>GET /disk1/storage/apache/htdocs/images/imagestore1/food/apples</td>
3874 <td>orage/apache/htdocs/images/imagestore1/food/apples.jpg HTTP/1.1</td>
3880 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3881 <div class="directive-section"><h2><a name="ServerAdmin" id="ServerAdmin">ServerAdmin</a> <a name="serveradmin" id="serveradmin">Directive</a></h2>
3882 <table class="directive">
3883 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Email address that the server includes in error
3884 messages sent to the client</td></tr>
3885 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAdmin <var>email-address</var>|<var>URL</var></code></td></tr>
3886 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3887 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3888 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3890 <p>The <code class="directive">ServerAdmin</code> sets the contact address
3891 that the server includes in any error messages it returns to the
3892 client. If the <code>httpd</code> doesn't recognize the supplied argument
3894 assumes, that it's an <var>email-address</var> and prepends it with
3895 <code>mailto:</code> in hyperlink targets. However, it's recommended to
3896 actually use an email address, since there are a lot of CGI scripts that
3897 make that assumption. If you want to use an URL, it should point to another
3898 server under your control. Otherwise users may not be able to contact you in
3901 <p>It may be worth setting up a dedicated address for this, e.g.</p>
3903 <pre class="prettyprint lang-config">ServerAdmin www-admin@foo.example.com</pre>
3905 <p>as users do not always mention that they are talking about the
3909 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3910 <div class="directive-section"><h2><a name="ServerAlias" id="ServerAlias">ServerAlias</a> <a name="serveralias" id="serveralias">Directive</a></h2>
3911 <table class="directive">
3912 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Alternate names for a host used when matching requests
3913 to name-virtual hosts</td></tr>
3914 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</code></td></tr>
3915 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
3916 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3917 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3919 <p>The <code class="directive">ServerAlias</code> directive sets the
3920 alternate names for a host, for use with <a href="../vhosts/name-based.html">name-based virtual hosts</a>. The
3921 <code class="directive">ServerAlias</code> may include wildcards, if appropriate.</p>
3923 <pre class="prettyprint lang-config">
3924 <VirtualHost *:80>
3925 ServerName server.example.com
3926 ServerAlias server server2.example.com server2
3927 ServerAlias *.example.com
3928 UseCanonicalName Off
3930 </VirtualHost>
3934 <p>Name-based virtual hosts for the best-matching set of <code class="directive"><a href="#virtualhost"><virtualhost></a></code>s are processed
3935 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
3936 (nor for ServerName vs. ServerAlias). </p>
3938 <p>The complete list of names in the <code class="directive">VirtualHost</code>
3939 directive are treated just like a (non wildcard)
3940 <code class="directive">ServerAlias</code>.</p>
3945 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3946 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
3949 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3950 <div class="directive-section"><h2><a name="ServerName" id="ServerName">ServerName</a> <a name="servername" id="servername">Directive</a></h2>
3951 <table class="directive">
3952 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hostname and port that the server uses to identify
3954 <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>
3955 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3956 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3957 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3959 <p>The <code class="directive">ServerName</code> directive sets the
3960 request scheme, hostname and
3961 port that the server uses to identify itself. This is used when
3962 creating redirection URLs.</p>
3964 <p>Additionally, <code class="directive">ServerName</code> is used (possibly
3965 in conjunction with <code class="directive">ServerAlias</code>) to uniquely
3966 identify a virtual host, when using <a href="../vhosts/name-based.html">name-based virtual hosts</a>.</p>
3968 <p>For example, if the name of the
3969 machine hosting the web server is <code>simple.example.com</code>,
3970 but the machine also has the DNS alias <code>www.example.com</code>
3971 and you wish the web server to be so identified, the following
3972 directive should be used:</p>
3974 <pre class="prettyprint lang-config">ServerName www.example.com</pre>
3977 <p>The <code class="directive">ServerName</code> directive
3978 may appear anywhere within the definition of a server. However,
3979 each appearance overrides the previous appearance (within that
3982 <p>If no <code class="directive">ServerName</code> is specified, then the
3983 server attempts to deduce the hostname by performing a reverse
3984 lookup on the IP address. If no port is specified in the
3985 <code class="directive">ServerName</code>, then the server will use the
3986 port from the incoming request. For optimal reliability and
3987 predictability, you should specify an explicit hostname and port
3988 using the <code class="directive">ServerName</code> directive.</p>
3990 <p>If you are using <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
3991 the <code class="directive">ServerName</code> inside a
3992 <code class="directive"><a href="#virtualhost"><VirtualHost></a></code>
3993 section specifies what hostname must appear in the request's
3994 <code>Host:</code> header to match this virtual host.</p>
3996 <p>Sometimes, the server runs behind a device that processes SSL,
3997 such as a reverse proxy, load balancer or SSL offload
3998 appliance. When this is the case, specify the
3999 <code>https://</code> scheme and the port number to which the
4000 clients connect in the <code class="directive">ServerName</code> directive
4001 to make sure that the server generates the correct
4002 self-referential URLs.
4005 <p>See the description of the
4006 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> and
4007 <code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code> directives for
4008 settings which determine whether self-referential URLs (e.g., by the
4009 <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> module) will refer to the
4010 specified port, or to the port number given in the client's request.
4013 <div class="warning">
4014 <p>Failure to set <code class="directive">ServerName</code> to a name that
4015 your server can resolve to an IP address will result in a startup
4016 warning. <code>httpd</code> will then use whatever hostname it can
4017 determine, using the system's <code>hostname</code> command. This
4018 will almost never be the hostname you actually want.</p>
4019 <div class="example"><p><code>
4020 httpd: Could not reliably determine the server's fully qualified domain name, using rocinante.local for ServerName
4027 <li><a href="../dns-caveats.html">Issues Regarding DNS and
4028 Apache HTTP Server</a></li>
4029 <li><a href="../vhosts/">Apache HTTP Server virtual host
4030 documentation</a></li>
4031 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
4032 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
4033 <li><code class="directive"><a href="#serveralias">ServerAlias</a></code></li>
4036 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4037 <div class="directive-section"><h2><a name="ServerPath" id="ServerPath">ServerPath</a> <a name="serverpath" id="serverpath">Directive</a></h2>
4038 <table class="directive">
4039 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Legacy URL pathname for a name-based virtual host that
4040 is accessed by an incompatible browser</td></tr>
4041 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerPath <var>URL-path</var></code></td></tr>
4042 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
4043 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4044 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4046 <p>The <code class="directive">ServerPath</code> directive sets the legacy
4047 URL pathname for a host, for use with <a href="../vhosts/">name-based virtual hosts</a>.</p>
4051 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4054 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4055 <div class="directive-section"><h2><a name="ServerRoot" id="ServerRoot">ServerRoot</a> <a name="serverroot" id="serverroot">Directive</a></h2>
4056 <table class="directive">
4057 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server installation</td></tr>
4058 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerRoot <var>directory-path</var></code></td></tr>
4059 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerRoot /usr/local/apache</code></td></tr>
4060 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4061 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4062 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4064 <p>The <code class="directive">ServerRoot</code> directive sets the
4065 directory in which the server lives. Typically it will contain the
4066 subdirectories <code>conf/</code> and <code>logs/</code>. Relative
4067 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
4068 relative to this directory.</p>
4070 <pre class="prettyprint lang-config">ServerRoot "/home/httpd"</pre>
4073 <p>The default location of <code class="directive">ServerRoot</code> may be
4074 modified by using the <code>--prefix</code> argument to
4075 <a href="../programs/configure.html"><code>configure</code></a>, and
4076 most third-party distributions of the server have a different
4077 default location from the one listed above.</p>
4082 <li><a href="../invoking.html">the <code>-d</code>
4083 option to <code>httpd</code></a></li>
4084 <li><a href="../misc/security_tips.html#serverroot">the
4085 security tips</a> for information on how to properly set
4086 permissions on the <code class="directive">ServerRoot</code></li>
4089 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4090 <div class="directive-section"><h2><a name="ServerSignature" id="ServerSignature">ServerSignature</a> <a name="serversignature" id="serversignature">Directive</a></h2>
4091 <table class="directive">
4092 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the footer on server-generated documents</td></tr>
4093 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerSignature On|Off|EMail</code></td></tr>
4094 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerSignature Off</code></td></tr>
4095 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4096 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
4097 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4098 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4100 <p>The <code class="directive">ServerSignature</code> directive allows the
4101 configuration of a trailing footer line under server-generated
4102 documents (error messages, <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> ftp directory
4103 listings, <code class="module"><a href="../mod/mod_info.html">mod_info</a></code> output, ...). The reason why you
4104 would want to enable such a footer line is that in a chain of proxies,
4105 the user often has no possibility to tell which of the chained servers
4106 actually produced a returned error message.</p>
4108 <p>The <code>Off</code>
4109 setting, which is the default, suppresses the footer line (and is
4110 therefore compatible with the behavior of Apache-1.2 and
4111 below). The <code>On</code> setting simply adds a line with the
4112 server version number and <code class="directive"><a href="#servername">ServerName</a></code> of the serving virtual host,
4113 and the <code>EMail</code> setting additionally creates a
4114 "mailto:" reference to the <code class="directive"><a href="#serveradmin">ServerAdmin</a></code> of the referenced
4117 <p>After version 2.0.44, the details of the server version number
4118 presented are controlled by the <code class="directive"><a href="#servertokens">ServerTokens</a></code> directive.</p>
4122 <li><code class="directive"><a href="#servertokens">ServerTokens</a></code></li>
4125 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4126 <div class="directive-section"><h2><a name="ServerTokens" id="ServerTokens">ServerTokens</a> <a name="servertokens" id="servertokens">Directive</a></h2>
4127 <table class="directive">
4128 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the <code>Server</code> HTTP response
4130 <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>
4131 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerTokens Full</code></td></tr>
4132 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4133 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4134 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4136 <p>This directive controls whether <code>Server</code> response
4137 header field which is sent back to clients includes a
4138 description of the generic OS-type of the server as well as
4139 information about compiled-in modules.</p>
4142 <dt><code>ServerTokens Full</code> (or not specified)</dt>
4144 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4145 (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
4147 <dt><code>ServerTokens Prod[uctOnly]</code></dt>
4149 <dd>Server sends (<em>e.g.</em>): <code>Server:
4152 <dt><code>ServerTokens Major</code></dt>
4154 <dd>Server sends (<em>e.g.</em>): <code>Server:
4155 Apache/2</code></dd>
4157 <dt><code>ServerTokens Minor</code></dt>
4159 <dd>Server sends (<em>e.g.</em>): <code>Server:
4160 Apache/2.4</code></dd>
4162 <dt><code>ServerTokens Min[imal]</code></dt>
4164 <dd>Server sends (<em>e.g.</em>): <code>Server:
4165 Apache/2.4.2</code></dd>
4167 <dt><code>ServerTokens OS</code></dt>
4169 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4174 <p>This setting applies to the entire server, and cannot be
4175 enabled or disabled on a virtualhost-by-virtualhost basis.</p>
4177 <p>After version 2.0.44, this directive also controls the
4178 information presented by the <code class="directive"><a href="#serversignature">ServerSignature</a></code> directive.</p>
4180 <div class="note">Setting <code class="directive">ServerTokens</code> to less than
4181 <code>minimal</code> is not recommended because it makes it more
4182 difficult to debug interoperational problems. Also note that
4183 disabling the Server: header does nothing at all to make your
4184 server more secure; the idea of "security through obscurity"
4185 is a myth and leads to a false sense of safety.</div>
4190 <li><code class="directive"><a href="#serversignature">ServerSignature</a></code></li>
4193 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4194 <div class="directive-section"><h2><a name="SetHandler" id="SetHandler">SetHandler</a> <a name="sethandler" id="sethandler">Directive</a></h2>
4195 <table class="directive">
4196 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be processed by a
4198 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetHandler <var>handler-name</var>|None</code></td></tr>
4199 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4200 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4201 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4202 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4204 <p>When placed into an <code>.htaccess</code> file or a
4205 <code class="directive"><a href="#directory"><Directory></a></code> or
4206 <code class="directive"><a href="#location"><Location></a></code>
4207 section, this directive forces all matching files to be parsed
4208 through the <a href="../handler.html">handler</a> given by
4209 <var>handler-name</var>. For example, if you had a directory you
4210 wanted to be parsed entirely as imagemap rule files, regardless
4211 of extension, you might put the following into an
4212 <code>.htaccess</code> file in that directory:</p>
4214 <pre class="prettyprint lang-config">SetHandler imap-file</pre>
4217 <p>Another example: if you wanted to have the server display a
4218 status report whenever a URL of
4219 <code>http://servername/status</code> was called, you might put
4220 the following into <code>httpd.conf</code>:</p>
4222 <pre class="prettyprint lang-config">
4223 <Location "/status">
4224 SetHandler server-status
4229 <p>You could also use this directive to configure a particular
4230 handler for files with a particular file extension. For example:</p>
4232 <pre class="prettyprint lang-config">
4233 <FilesMatch \.php$>
4234 SetHandler application/x-httpd-php
4239 <p>You can override an earlier defined <code class="directive">SetHandler</code>
4240 directive by using the value <code>None</code>.</p>
4242 <div class="note"><h3>Note</h3>
4243 <p>Because <code class="directive">SetHandler</code> overrides default handlers,
4244 normal behavior such as handling of URLs ending in a slash (/) as
4245 directories or index files is suppressed.</p></div>
4249 <li><code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code></li>
4252 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4253 <div class="directive-section"><h2><a name="SetInputFilter" id="SetInputFilter">SetInputFilter</a> <a name="setinputfilter" id="setinputfilter">Directive</a></h2>
4254 <table class="directive">
4255 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process client requests and POST
4257 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetInputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4258 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4259 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4260 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4261 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4263 <p>The <code class="directive">SetInputFilter</code> directive sets the
4264 filter or filters which will process client requests and POST
4265 input when they are received by the server. This is in addition to
4266 any filters defined elsewhere, including the
4267 <code class="directive"><a href="../mod/mod_mime.html#addinputfilter">AddInputFilter</a></code>
4270 <p>If more than one filter is specified, they must be separated
4271 by semicolons in the order in which they should process the
4276 <li><a href="../filter.html">Filters</a> documentation</li>
4279 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4280 <div class="directive-section"><h2><a name="SetOutputFilter" id="SetOutputFilter">SetOutputFilter</a> <a name="setoutputfilter" id="setoutputfilter">Directive</a></h2>
4281 <table class="directive">
4282 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process responses from the
4284 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4285 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4286 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4287 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4288 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4290 <p>The <code class="directive">SetOutputFilter</code> directive sets the filters
4291 which will process responses from the server before they are
4292 sent to the client. This is in addition to any filters defined
4293 elsewhere, including the
4294 <code class="directive"><a href="../mod/mod_mime.html#addoutputfilter">AddOutputFilter</a></code>
4297 <p>For example, the following configuration will process all files
4298 in the <code>/www/data/</code> directory for server-side
4301 <pre class="prettyprint lang-config">
4302 <Directory "/www/data/">
4303 SetOutputFilter INCLUDES
4308 <p>If more than one filter is specified, they must be separated
4309 by semicolons in the order in which they should process the
4314 <li><a href="../filter.html">Filters</a> documentation</li>
4317 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4318 <div class="directive-section"><h2><a name="TimeOut" id="TimeOut">TimeOut</a> <a name="timeout" id="timeout">Directive</a></h2>
4319 <table class="directive">
4320 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for
4321 certain events before failing a request</td></tr>
4322 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TimeOut <var>seconds</var></code></td></tr>
4323 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TimeOut 60</code></td></tr>
4324 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4325 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4326 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4328 <p>The <code class="directive">TimeOut</code> directive defines the length
4329 of time Apache httpd will wait for I/O in various circumstances:</p>
4332 <li>When reading data from the client, the length of time to
4333 wait for a TCP packet to arrive if the read buffer is
4336 <li>When writing data to the client, the length of time to wait
4337 for an acknowledgement of a packet if the send buffer is
4340 <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>,
4341 the length of time to wait for output from a CGI script.</li>
4343 <li>In <code class="module"><a href="../mod/mod_ext_filter.html">mod_ext_filter</a></code>, the length of time to
4344 wait for output from a filtering process.</li>
4346 <li>In <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>, the default timeout value if
4347 <code class="directive"><a href="../mod/mod_proxy.html#proxytimeout">ProxyTimeout</a></code> is not
4353 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4354 <div class="directive-section"><h2><a name="TraceEnable" id="TraceEnable">TraceEnable</a> <a name="traceenable" id="traceenable">Directive</a></h2>
4355 <table class="directive">
4356 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines the behavior on <code>TRACE</code> requests</td></tr>
4357 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TraceEnable <var>[on|off|extended]</var></code></td></tr>
4358 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TraceEnable on</code></td></tr>
4359 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4360 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4361 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4363 <p>This directive overrides the behavior of <code>TRACE</code> for both
4364 the core server and <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>. The default
4365 <code>TraceEnable on</code> permits <code>TRACE</code> requests per
4366 RFC 2616, which disallows any request body to accompany the request.
4367 <code>TraceEnable off</code> causes the core server and
4368 <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> to return a <code>405</code> (Method not
4369 allowed) error to the client.</p>
4371 <p>Finally, for testing and diagnostic purposes only, request
4372 bodies may be allowed using the non-compliant <code>TraceEnable
4373 extended</code> directive. The core (as an origin server) will
4374 restrict the request body to 64k (plus 8k for chunk headers if
4375 <code>Transfer-Encoding: chunked</code> is used). The core will
4376 reflect the full headers and all chunk headers with the response
4377 body. As a proxy server, the request body is not restricted to 64k.</p>
4379 <div class="note"><h3>Note</h3>
4380 <p>Despite claims to the contrary, <code>TRACE</code> is not
4381 a security vulnerability and there is no viable reason for
4382 it to be disabled. Doing so necessarily makes your server
4387 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4388 <div class="directive-section"><h2><a name="UnDefine" id="UnDefine">UnDefine</a> <a name="undefine" id="undefine">Directive</a></h2>
4389 <table class="directive">
4390 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Undefine the existence of a variable</td></tr>
4391 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UnDefine <var>parameter-name</var></code></td></tr>
4392 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</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>Undoes the effect of a <code class="directive"><a href="#define">Define</a></code> or
4397 of passing a <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</p>
4398 <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
4399 <code>-D</code> arguments in any startup scripts.</p>
4402 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4403 <div class="directive-section"><h2><a name="UseCanonicalName" id="UseCanonicalName">UseCanonicalName</a> <a name="usecanonicalname" id="usecanonicalname">Directive</a></h2>
4404 <table class="directive">
4405 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own name and
4407 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalName On|Off|DNS</code></td></tr>
4408 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalName Off</code></td></tr>
4409 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4410 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4411 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4413 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4414 URL -- that is, a URL that refers back to the same server. With
4415 <code>UseCanonicalName On</code> Apache httpd will use the hostname and port
4416 specified in the <code class="directive"><a href="#servername">ServerName</a></code>
4417 directive to construct the canonical name for the server. This name
4418 is used in all self-referential URLs, and for the values of
4419 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>
4421 <p>With <code>UseCanonicalName Off</code> Apache httpd will form
4422 self-referential URLs using the hostname and port supplied by
4423 the client if any are supplied (otherwise it will use the
4424 canonical name, as defined above). These values are the same
4425 that are used to implement <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
4426 and are available with the same clients. The CGI variables
4427 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
4428 constructed from the client supplied values as well.</p>
4430 <p>An example where this may be useful is on an intranet server
4431 where you have users connecting to the machine using short
4432 names such as <code>www</code>. You'll notice that if the users
4433 type a shortname, and a URL which is a directory, such as
4434 <code>http://www/splat</code>, <em>without the trailing
4435 slash</em> then Apache httpd will redirect them to
4436 <code>http://www.example.com/splat/</code>. If you have
4437 authentication enabled, this will cause the user to have to
4438 authenticate twice (once for <code>www</code> and once again
4439 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">
4440 the FAQ on this subject for more information</a>). But if
4441 <code class="directive">UseCanonicalName</code> is set <code>Off</code>, then
4442 Apache httpd will redirect to <code>http://www/splat/</code>.</p>
4444 <p>There is a third option, <code>UseCanonicalName DNS</code>,
4445 which is intended for use with mass IP-based virtual hosting to
4446 support ancient clients that do not provide a
4447 <code>Host:</code> header. With this option Apache httpd does a
4448 reverse DNS lookup on the server IP address that the client
4449 connected to in order to work out self-referential URLs.</p>
4451 <div class="warning"><h3>Warning</h3>
4452 <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>
4453 they may be broken by this option. The client is essentially free
4454 to give whatever value they want as a hostname. But if the CGI is
4455 only using <code>SERVER_NAME</code> to construct self-referential URLs
4456 then it should be just fine.</p>
4461 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
4462 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4463 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4466 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4467 <div class="directive-section"><h2><a name="UseCanonicalPhysicalPort" id="UseCanonicalPhysicalPort">UseCanonicalPhysicalPort</a> <a name="usecanonicalphysicalport" id="usecanonicalphysicalport">Directive</a></h2>
4468 <table class="directive">
4469 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own port</td></tr>
4470 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalPhysicalPort On|Off</code></td></tr>
4471 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalPhysicalPort Off</code></td></tr>
4472 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4473 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4474 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4476 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4477 URL -- that is, a URL that refers back to the same server. With
4478 <code>UseCanonicalPhysicalPort On</code> Apache httpd will, when
4479 constructing the canonical port for the server to honor
4480 the <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> directive,
4481 provide the actual physical port number being used by this request
4482 as a potential port. With <code>UseCanonicalPhysicalPort Off</code>
4483 Apache httpd will not ever use the actual physical port number, instead
4484 relying on all configured information to construct a valid port number.</p>
4486 <div class="note"><h3>Note</h3>
4487 <p>The ordering of the lookup when the physical port is used is as
4490 <dt><code>UseCanonicalName On</code></dt>
4493 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4494 <li>Physical port</li>
4495 <li>Default port</li>
4498 <dt><code>UseCanonicalName Off | DNS</code></dt>
4501 <li>Parsed port from <code>Host:</code> header</li>
4502 <li>Physical port</li>
4503 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4504 <li>Default port</li>
4509 <p>With <code>UseCanonicalPhysicalPort Off</code>, the
4510 physical ports are removed from the ordering.</p>
4516 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
4517 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4518 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4521 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4522 <div class="directive-section"><h2><a name="VirtualHost" id="VirtualHost"><VirtualHost></a> <a name="virtualhost" id="virtualhost">Directive</a></h2>
4523 <table class="directive">
4524 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only to a specific
4525 hostname or IP address</td></tr>
4526 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><VirtualHost
4527 <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
4528 ...> ... </VirtualHost></code></td></tr>
4529 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4530 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4531 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4533 <p><code class="directive"><VirtualHost></code> and
4534 <code></VirtualHost></code> are used to enclose a group of
4535 directives that will apply only to a particular virtual host. Any
4536 directive that is allowed in a virtual host context may be
4537 used. When the server receives a request for a document on a
4538 particular virtual host, it uses the configuration directives
4539 enclosed in the <code class="directive"><VirtualHost></code>
4540 section. <var>Addr</var> can be any of the following, optionally followed by
4541 a colon and a port number (or *):</p>
4544 <li>The IP address of the virtual host;</li>
4546 <li>A fully qualified domain name for the IP address of the
4547 virtual host (not recommended);</li>
4549 <li>The character <code>*</code>, which acts as a wildcard and matches
4550 any IP address.</li>
4552 <li>The string <code>_default_</code>, which is an alias for <code>*</code></li>
4556 <pre class="prettyprint lang-config">
4557 <VirtualHost 10.1.2.3:80>
4558 ServerAdmin webmaster@host.example.com
4559 DocumentRoot /www/docs/host.example.com
4560 ServerName host.example.com
4561 ErrorLog logs/host.example.com-error_log
4562 TransferLog logs/host.example.com-access_log
4563 </VirtualHost>
4568 <p>IPv6 addresses must be specified in square brackets because
4569 the optional port number could not be determined otherwise. An
4570 IPv6 example is shown below:</p>
4572 <pre class="prettyprint lang-config">
4573 <VirtualHost [2001:db8::a00:20ff:fea7:ccea]:80>
4574 ServerAdmin webmaster@host.example.com
4575 DocumentRoot /www/docs/host.example.com
4576 ServerName host.example.com
4577 ErrorLog logs/host.example.com-error_log
4578 TransferLog logs/host.example.com-access_log
4579 </VirtualHost>
4583 <p>Each Virtual Host must correspond to a different IP address,
4584 different port number or a different host name for the server,
4585 in the former case the server machine must be configured to
4586 accept IP packets for multiple addresses. (If the machine does
4587 not have multiple network interfaces, then this can be
4588 accomplished with the <code>ifconfig alias</code> command -- if
4589 your OS supports it).</p>
4591 <div class="note"><h3>Note</h3>
4592 <p>The use of <code class="directive"><VirtualHost></code> does
4593 <strong>not</strong> affect what addresses Apache httpd listens on. You
4594 may need to ensure that Apache httpd is listening on the correct addresses
4595 using <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>.</p>
4598 <p>A <code class="directive"><a href="#servername">ServerName</a></code> should be
4599 specified inside each <code class="directive"><VirtualHost></code> block. If it is absent, the
4600 <code class="directive"><a href="#servername">ServerName</a></code> from the "main"
4601 server configuration will be inherited.</p>
4603 <p>When a request is received, the server first maps it to the best matching
4604 <code class="directive"><VirtualHost></code> based on the local
4605 IP address and port combination only. Non-wildcards have a higher
4606 precedence. If no match based on IP and port occurs at all, the
4607 "main" server configuration is used.</p>
4609 <p>If multiple virtual hosts contain the best matching IP address and port,
4610 the server selects from these virtual hosts the best match based on the
4611 requested hostname. If no matching name-based virtual host is found,
4612 then the first listed virtual host that matched the IP address will be
4613 used. As a consequence, the first listed virtual host for a given IP address
4614 and port combination is default virtual host for that IP and port
4617 <div class="warning"><h3>Security</h3>
4618 <p>See the <a href="../misc/security_tips.html">security tips</a>
4619 document for details on why your security could be compromised if the
4620 directory where log files are stored is writable by anyone other
4621 than the user that starts the server.</p>
4626 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4627 <li><a href="../dns-caveats.html">Issues Regarding DNS and
4628 Apache HTTP Server</a></li>
4629 <li><a href="../bind.html">Setting
4630 which addresses and ports Apache HTTP Server uses</a></li>
4631 <li><a href="../sections.html">How <Directory>, <Location>
4632 and <Files> sections work</a> for an explanation of how these
4633 different sections are combined when a request is received</li>
4636 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4637 <div class="directive-section"><h2><a name="Warning" id="Warning">Warning</a> <a name="warning" id="warning">Directive</a></h2>
4638 <table class="directive">
4639 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Warn from configuration parsing with a custom message</td></tr>
4640 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Warning <var>message</var></code></td></tr>
4641 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4642 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4643 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4644 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.5 and later</td></tr>
4646 <p>If an issue can be detected from within the configuration, this
4647 directive can be used to generate a custom warning message. The
4648 configuration parsing is not halted. The typical use it to check
4649 whether some user define options are set, and warn if not.</p>
4651 <pre class="prettyprint lang-config">
4653 # tell when ReverseProxy is not set
4654 <IfDefine !ReverseProxy>
4655 Warning "reverse proxy is not started, hope this is okay!"
4658 <IfDefine ReverseProxy>
4659 # define custom proxy configuration
4667 <div class="bottomlang">
4668 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
4669 <a href="../en/mod/core.html" title="English"> en </a> |
4670 <a href="../es/mod/core.html" hreflang="es" rel="alternate" title="Español"> es </a> |
4671 <a href="../fr/mod/core.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
4672 <a href="../ja/mod/core.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
4673 <a href="../tr/mod/core.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p>
4674 </div><div class="top"><a href="#page-header"><img src="../images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Comments</a></h2><div class="warning"><strong>Notice:</strong><br />This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed again by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Freenode, or sent to our <a href="http://httpd.apache.org/lists.html">mailing lists</a>.</div>
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4692 <p class="apache">Copyright 2014 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p>
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