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15 <p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p>
16 <p class="apache">Apache HTTP Server Version 2.3</p>
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20 <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 2.3</a> > <a href="./">Modules</a></div>
21 <div id="page-content">
22 <div id="preamble"><h1>Apache Core Features</h1>
24 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
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31 <table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Core Apache HTTP Server features that are always
33 <tr><th><a href="module-dict.html#Status">Status:</a></th><td>Core</td></tr></table>
35 <div id="quickview"><h3 class="directives">Directives</h3>
37 <li><img alt="" src="../images/down.gif" /> <a href="#acceptfilter">AcceptFilter</a></li>
38 <li><img alt="" src="../images/down.gif" /> <a href="#acceptpathinfo">AcceptPathInfo</a></li>
39 <li><img alt="" src="../images/down.gif" /> <a href="#accessfilename">AccessFileName</a></li>
40 <li><img alt="" src="../images/down.gif" /> <a href="#adddefaultcharset">AddDefaultCharset</a></li>
41 <li><img alt="" src="../images/down.gif" /> <a href="#allowencodedslashes">AllowEncodedSlashes</a></li>
42 <li><img alt="" src="../images/down.gif" /> <a href="#allowoverride">AllowOverride</a></li>
43 <li><img alt="" src="../images/down.gif" /> <a href="#cgimapextension">CGIMapExtension</a></li>
44 <li><img alt="" src="../images/down.gif" /> <a href="#contentdigest">ContentDigest</a></li>
45 <li><img alt="" src="../images/down.gif" /> <a href="#defaulttype">DefaultType</a></li>
46 <li><img alt="" src="../images/down.gif" /> <a href="#define">Define</a></li>
47 <li><img alt="" src="../images/down.gif" /> <a href="#directory"><Directory></a></li>
48 <li><img alt="" src="../images/down.gif" /> <a href="#directorymatch"><DirectoryMatch></a></li>
49 <li><img alt="" src="../images/down.gif" /> <a href="#documentroot">DocumentRoot</a></li>
50 <li><img alt="" src="../images/down.gif" /> <a href="#enablemmap">EnableMMAP</a></li>
51 <li><img alt="" src="../images/down.gif" /> <a href="#enablesendfile">EnableSendfile</a></li>
52 <li><img alt="" src="../images/down.gif" /> <a href="#error">Error</a></li>
53 <li><img alt="" src="../images/down.gif" /> <a href="#errordocument">ErrorDocument</a></li>
54 <li><img alt="" src="../images/down.gif" /> <a href="#errorlog">ErrorLog</a></li>
55 <li><img alt="" src="../images/down.gif" /> <a href="#errorlogformat">ErrorLogFormat</a></li>
56 <li><img alt="" src="../images/down.gif" /> <a href="#extendedstatus">ExtendedStatus</a></li>
57 <li><img alt="" src="../images/down.gif" /> <a href="#fileetag">FileETag</a></li>
58 <li><img alt="" src="../images/down.gif" /> <a href="#files"><Files></a></li>
59 <li><img alt="" src="../images/down.gif" /> <a href="#filesmatch"><FilesMatch></a></li>
60 <li><img alt="" src="../images/down.gif" /> <a href="#forcetype">ForceType</a></li>
61 <li><img alt="" src="../images/down.gif" /> <a href="#gprofdir">GprofDir</a></li>
62 <li><img alt="" src="../images/down.gif" /> <a href="#hostnamelookups">HostnameLookups</a></li>
63 <li><img alt="" src="../images/down.gif" /> <a href="#if"><If></a></li>
64 <li><img alt="" src="../images/down.gif" /> <a href="#ifdefine"><IfDefine></a></li>
65 <li><img alt="" src="../images/down.gif" /> <a href="#ifmodule"><IfModule></a></li>
66 <li><img alt="" src="../images/down.gif" /> <a href="#include">Include</a></li>
67 <li><img alt="" src="../images/down.gif" /> <a href="#keepalive">KeepAlive</a></li>
68 <li><img alt="" src="../images/down.gif" /> <a href="#keepalivetimeout">KeepAliveTimeout</a></li>
69 <li><img alt="" src="../images/down.gif" /> <a href="#limit"><Limit></a></li>
70 <li><img alt="" src="../images/down.gif" /> <a href="#limitexcept"><LimitExcept></a></li>
71 <li><img alt="" src="../images/down.gif" /> <a href="#limitinternalrecursion">LimitInternalRecursion</a></li>
72 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestbody">LimitRequestBody</a></li>
73 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfields">LimitRequestFields</a></li>
74 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfieldsize">LimitRequestFieldSize</a></li>
75 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestline">LimitRequestLine</a></li>
76 <li><img alt="" src="../images/down.gif" /> <a href="#limitxmlrequestbody">LimitXMLRequestBody</a></li>
77 <li><img alt="" src="../images/down.gif" /> <a href="#location"><Location></a></li>
78 <li><img alt="" src="../images/down.gif" /> <a href="#locationmatch"><LocationMatch></a></li>
79 <li><img alt="" src="../images/down.gif" /> <a href="#loglevel">LogLevel</a></li>
80 <li><img alt="" src="../images/down.gif" /> <a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></li>
81 <li><img alt="" src="../images/down.gif" /> <a href="#mutex">Mutex</a></li>
82 <li><img alt="" src="../images/down.gif" /> <a href="#namevirtualhost">NameVirtualHost</a></li>
83 <li><img alt="" src="../images/down.gif" /> <a href="#options">Options</a></li>
84 <li><img alt="" src="../images/down.gif" /> <a href="#protocol">Protocol</a></li>
85 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitcpu">RLimitCPU</a></li>
86 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitmem">RLimitMEM</a></li>
87 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitnproc">RLimitNPROC</a></li>
88 <li><img alt="" src="../images/down.gif" /> <a href="#scriptinterpretersource">ScriptInterpreterSource</a></li>
89 <li><img alt="" src="../images/down.gif" /> <a href="#seerequesttail">SeeRequestTail</a></li>
90 <li><img alt="" src="../images/down.gif" /> <a href="#serveradmin">ServerAdmin</a></li>
91 <li><img alt="" src="../images/down.gif" /> <a href="#serveralias">ServerAlias</a></li>
92 <li><img alt="" src="../images/down.gif" /> <a href="#servername">ServerName</a></li>
93 <li><img alt="" src="../images/down.gif" /> <a href="#serverpath">ServerPath</a></li>
94 <li><img alt="" src="../images/down.gif" /> <a href="#serverroot">ServerRoot</a></li>
95 <li><img alt="" src="../images/down.gif" /> <a href="#serversignature">ServerSignature</a></li>
96 <li><img alt="" src="../images/down.gif" /> <a href="#servertokens">ServerTokens</a></li>
97 <li><img alt="" src="../images/down.gif" /> <a href="#sethandler">SetHandler</a></li>
98 <li><img alt="" src="../images/down.gif" /> <a href="#setinputfilter">SetInputFilter</a></li>
99 <li><img alt="" src="../images/down.gif" /> <a href="#setoutputfilter">SetOutputFilter</a></li>
100 <li><img alt="" src="../images/down.gif" /> <a href="#timeout">TimeOut</a></li>
101 <li><img alt="" src="../images/down.gif" /> <a href="#traceenable">TraceEnable</a></li>
102 <li><img alt="" src="../images/down.gif" /> <a href="#undefine">UnDefine</a></li>
103 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalname">UseCanonicalName</a></li>
104 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></li>
105 <li><img alt="" src="../images/down.gif" /> <a href="#virtualhost"><VirtualHost></a></li>
109 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
110 <div class="directive-section"><h2><a name="AcceptFilter" id="AcceptFilter">AcceptFilter</a> <a name="acceptfilter" id="acceptfilter">Directive</a></h2>
111 <table class="directive">
112 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures optimizations for a Protocol's Listener Sockets</td></tr>
113 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptFilter <var>protocol</var> <var>accept_filter</var></code></td></tr>
114 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
115 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
116 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
117 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.1.5 and later.
118 On Windows from Apache httpd 2.3.3 and later.</td></tr>
120 <p>This directive enables operating system specific optimizations for a
121 listening socket by the <code class="directive">Protocol</code>type.
122 The basic premise is for the kernel to not send a socket to the server
123 process until either data is received or an entire HTTP Request is buffered.
124 Only <a href="http://www.freebsd.org/cgi/man.cgi?query=accept_filter&sektion=9">
125 FreeBSD's Accept Filters</a>, Linux's more primitive
126 <code>TCP_DEFER_ACCEPT</code>, and Windows' optimized AcceptEx()
127 are currently supported.</p>
129 <p>Using <code>none</code> for an argument will disable any accept filters
130 for that protocol. This is useful for protocols that require a server
131 send data first, such as <code>ftp:</code> or <code>nntp</code>:</p>
132 <div class="example"><p><code>AcceptFilter nntp none</code></p></div>
134 <p>The default protocol names are <code>https</code> for port 443
135 and <code>http</code> for all other ports. To specify another protocol
136 is being used with a listening port, add the <var>protocol</var>
137 argument to the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>
140 <p>The default values on FreeBSD are:</p>
141 <div class="example"><p><code>
142 AcceptFilter http httpready <br />
143 AcceptFilter https dataready
146 <p>The <code>httpready</code> accept filter buffers entire HTTP requests at
147 the kernel level. Once an entire request is received, the kernel then
148 sends it to the server. See the
149 <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_http&sektion=9">
150 accf_http(9)</a> man page for more details. Since HTTPS requests are
151 encrypted only the <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_data&sektion=9">
152 accf_data(9)</a> filter is used.</p>
154 <p>The default values on Linux are:</p>
155 <div class="example"><p><code>
156 AcceptFilter http data <br />
157 AcceptFilter https data
160 <p>Linux's <code>TCP_DEFER_ACCEPT</code> does not support buffering http
161 requests. Any value besides <code>none</code> will enable
162 <code>TCP_DEFER_ACCEPT</code> on that listener. For more details
164 <a href="http://homepages.cwi.nl/~aeb/linux/man2html/man7/tcp.7.html">
165 tcp(7)</a> man page.</p>
167 <p>The default values on Windows are:</p>
168 <div class="example"><p><code>
169 AcceptFilter http data <br />
170 AcceptFilter https data
173 <p>Window's mpm_winnt interprets the AcceptFilter to toggle the AcceptEx()
174 API, and does not support http protocol buffering. There are two values
175 which utilize the Windows AcceptEx() API and will recycle network
176 sockets between connections. <code>data</code> waits until data has
177 been transmitted as documented above, and the initial data buffer and
178 network endpoint addresses are all retrieved from the single AcceptEx()
179 invocation. <code>connect</code> will use the AcceptEx() API, also
180 retrieve the network endpoint addresses, but like <code>none</code>
181 the <code>connect</code> option does not wait for the initial data
184 <p>On Windows, <code>none</code> uses accept() rather than AcceptEx()
185 and will not recycle sockets between connections. This is useful for
186 network adapters with broken driver support, as well as some virtual
187 network providers such as vpn drivers, or spam, virus or spyware
193 <li><code class="directive">Protocol</code></li>
196 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
197 <div class="directive-section"><h2><a name="AcceptPathInfo" id="AcceptPathInfo">AcceptPathInfo</a> <a name="acceptpathinfo" id="acceptpathinfo">Directive</a></h2>
198 <table class="directive">
199 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Resources accept trailing pathname information</td></tr>
200 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptPathInfo On|Off|Default</code></td></tr>
201 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AcceptPathInfo Default</code></td></tr>
202 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
203 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
204 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
205 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
206 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.0.30 and later</td></tr>
209 <p>This directive controls whether requests that contain trailing
210 pathname information that follows an actual filename (or
211 non-existent file in an existing directory) will be accepted or
212 rejected. The trailing pathname information can be made
213 available to scripts in the <code>PATH_INFO</code> environment
216 <p>For example, assume the location <code>/test/</code> points to
217 a directory that contains only the single file
218 <code>here.html</code>. Then requests for
219 <code>/test/here.html/more</code> and
220 <code>/test/nothere.html/more</code> both collect
221 <code>/more</code> as <code>PATH_INFO</code>.</p>
223 <p>The three possible arguments for the
224 <code class="directive">AcceptPathInfo</code> directive are:</p>
226 <dt><code>Off</code></dt><dd>A request will only be accepted if it
227 maps to a literal path that exists. Therefore a request with
228 trailing pathname information after the true filename such as
229 <code>/test/here.html/more</code> in the above example will return
230 a 404 NOT FOUND error.</dd>
232 <dt><code>On</code></dt><dd>A request will be accepted if a
233 leading path component maps to a file that exists. The above
234 example <code>/test/here.html/more</code> will be accepted if
235 <code>/test/here.html</code> maps to a valid file.</dd>
237 <dt><code>Default</code></dt><dd>The treatment of requests with
238 trailing pathname information is determined by the <a href="../handler.html">handler</a> responsible for the request.
239 The core handler for normal files defaults to rejecting
240 <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
241 <code>PATH_INFO</code> by default.</dd>
244 <p>The primary purpose of the <code>AcceptPathInfo</code>
245 directive is to allow you to override the handler's choice of
246 accepting or rejecting <code>PATH_INFO</code>. This override is required,
247 for example, when you use a <a href="../filter.html">filter</a>, such
248 as <a href="mod_include.html">INCLUDES</a>, to generate content
249 based on <code>PATH_INFO</code>. The core handler would usually reject
250 the request, so you can use the following configuration to enable
253 <div class="example"><p><code>
254 <Files "mypaths.shtml"><br />
255 <span class="indent">
256 Options +Includes<br />
257 SetOutputFilter INCLUDES<br />
258 AcceptPathInfo On<br />
265 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
266 <div class="directive-section"><h2><a name="AccessFileName" id="AccessFileName">AccessFileName</a> <a name="accessfilename" id="accessfilename">Directive</a></h2>
267 <table class="directive">
268 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Name of the distributed configuration file</td></tr>
269 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AccessFileName <var>filename</var> [<var>filename</var>] ...</code></td></tr>
270 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AccessFileName .htaccess</code></td></tr>
271 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
272 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
273 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
275 <p>While processing a request the server looks for
276 the first existing configuration file from this list of names in
277 every directory of the path to the document, if distributed
278 configuration files are <a href="#allowoverride">enabled for that
279 directory</a>. For example:</p>
281 <div class="example"><p><code>
285 <p>before returning the document
286 <code>/usr/local/web/index.html</code>, the server will read
287 <code>/.acl</code>, <code>/usr/.acl</code>,
288 <code>/usr/local/.acl</code> and <code>/usr/local/web/.acl</code>
289 for directives, unless they have been disabled with</p>
291 <div class="example"><p><code>
292 <Directory /><br />
293 <span class="indent">
294 AllowOverride None<br />
301 <li><code class="directive"><a href="#allowoverride">AllowOverride</a></code></li>
302 <li><a href="../configuring.html">Configuration Files</a></li>
303 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
306 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
307 <div class="directive-section"><h2><a name="AddDefaultCharset" id="AddDefaultCharset">AddDefaultCharset</a> <a name="adddefaultcharset" id="adddefaultcharset">Directive</a></h2>
308 <table class="directive">
309 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Default charset parameter to be added when a response
310 content-type is <code>text/plain</code> or <code>text/html</code></td></tr>
311 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AddDefaultCharset On|Off|<var>charset</var></code></td></tr>
312 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AddDefaultCharset Off</code></td></tr>
313 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
314 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
315 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
316 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
318 <p>This directive specifies a default value for the media type
319 charset parameter (the name of a character encoding) to be added
320 to a response if and only if the response's content-type is either
321 <code>text/plain</code> or <code>text/html</code>. This should override
322 any charset specified in the body of the response via a <code>META</code>
323 element, though the exact behavior is often dependent on the user's client
324 configuration. A setting of <code>AddDefaultCharset Off</code>
325 disables this functionality. <code>AddDefaultCharset On</code> enables
326 a default charset of <code>iso-8859-1</code>. Any other value is assumed
327 to be the <var>charset</var> to be used, which should be one of the
328 <a href="http://www.iana.org/assignments/character-sets">IANA registered
329 charset values</a> for use in Internet media types (MIME types).
332 <div class="example"><p><code>
333 AddDefaultCharset utf-8
336 <p><code class="directive">AddDefaultCharset</code> should only be used when all
337 of the text resources to which it applies are known to be in that
338 character encoding and it is too inconvenient to label their charset
339 individually. One such example is to add the charset parameter
340 to resources containing generated content, such as legacy CGI
341 scripts, that might be vulnerable to cross-site scripting attacks
342 due to user-provided data being included in the output. Note, however,
343 that a better solution is to just fix (or delete) those scripts, since
344 setting a default charset does not protect users that have enabled
345 the "auto-detect character encoding" feature on their browser.</p>
349 <li><code class="directive"><a href="../mod/mod_mime.html#addcharset">AddCharset</a></code></li>
352 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
353 <div class="directive-section"><h2><a name="AllowEncodedSlashes" id="AllowEncodedSlashes">AllowEncodedSlashes</a> <a name="allowencodedslashes" id="allowencodedslashes">Directive</a></h2>
354 <table class="directive">
355 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines whether encoded path separators in URLs are allowed to
356 be passed through</td></tr>
357 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowEncodedSlashes On|Off</code></td></tr>
358 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowEncodedSlashes Off</code></td></tr>
359 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
360 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
361 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
362 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.0.46 and later</td></tr>
364 <p>The <code class="directive">AllowEncodedSlashes</code> directive allows URLs
365 which contain encoded path separators (<code>%2F</code> for <code>/</code>
366 and additionally <code>%5C</code> for <code>\</code> on according systems)
367 to be used. Normally such URLs are refused with a 404 (Not found) error.</p>
369 <p>Turning <code class="directive">AllowEncodedSlashes</code> <code>On</code> is
370 mostly useful when used in conjunction with <code>PATH_INFO</code>.</p>
372 <div class="note"><h3>Note</h3>
373 <p>Allowing encoded slashes does <em>not</em> imply <em>decoding</em>.
374 Occurrences of <code>%2F</code> or <code>%5C</code> (<em>only</em> on
375 according systems) will be left as such in the otherwise decoded URL
381 <li><code class="directive"><a href="#acceptpathinfo">AcceptPathInfo</a></code></li>
384 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
385 <div class="directive-section"><h2><a name="AllowOverride" id="AllowOverride">AllowOverride</a> <a name="allowoverride" id="allowoverride">Directive</a></h2>
386 <table class="directive">
387 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Types of directives that are allowed in
388 <code>.htaccess</code> files</td></tr>
389 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowOverride All|None|<var>directive-type</var>
390 [<var>directive-type</var>] ...</code></td></tr>
391 <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>
392 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
393 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
394 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
396 <p>When the server finds an <code>.htaccess</code> file (as
397 specified by <code class="directive"><a href="#accessfilename">AccessFileName</a></code>)
398 it needs to know which directives declared in that file can override
399 earlier configuration directives.</p>
401 <div class="note"><h3>Only available in <Directory> sections</h3>
402 <code class="directive">AllowOverride</code> is valid only in
403 <code class="directive"><a href="#directory"><Directory></a></code>
404 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
405 <code class="directive"><a href="#files"><Files></a></code> sections.
408 <p>When this directive is set to <code>None</code>, then
409 <a href="#accessfilename">.htaccess</a> files are completely ignored.
410 In this case, the server will not even attempt to read
411 <code>.htaccess</code> files in the filesystem.</p>
413 <p>When this directive is set to <code>All</code>, then any
414 directive which has the .htaccess <a href="directive-dict.html#Context">Context</a> is allowed in
415 <code>.htaccess</code> files.</p>
417 <p>The <var>directive-type</var> can be one of the following
418 groupings of directives.</p>
425 Allow use of the authorization directives (<code class="directive"><a href="../mod/mod_authn_dbm.html#authdbmgroupfile">AuthDBMGroupFile</a></code>,
426 <code class="directive"><a href="../mod/mod_authn_dbm.html#authdbmuserfile">AuthDBMUserFile</a></code>,
427 <code class="directive"><a href="../mod/mod_authz_groupfile.html#authgroupfile">AuthGroupFile</a></code>,
428 <code class="directive"><a href="../mod/mod_authn_core.html#authname">AuthName</a></code>,
429 <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>
434 Allow use of the directives controlling document types
435 (<code class="directive"><a href="#errordocument">ErrorDocument</a></code>,
436 <code class="directive"><a href="#forcetype">ForceType</a></code>,
437 <code class="directive"><a href="../mod/mod_negotiation.html#languagepriority">LanguagePriority</a></code>,
438 <code class="directive"><a href="#sethandler">SetHandler</a></code>,
439 <code class="directive"><a href="#setinputfilter">SetInputFilter</a></code>,
440 <code class="directive"><a href="#setoutputfilter">SetOutputFilter</a></code>, and
441 <code class="module"><a href="../mod/mod_mime.html">mod_mime</a></code> Add* and Remove* directives),
442 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>),
443 <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>) and
444 <code class="directive"><a href="../mod/mod_actions.html#action">Action</a></code> from
445 <code class="module"><a href="../mod/mod_actions.html">mod_actions</a></code>.
451 Allow use of the directives controlling directory indexing
452 (<code class="directive"><a href="../mod/mod_autoindex.html#adddescription">AddDescription</a></code>,
453 <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>,
454 <code class="directive"><a href="../mod/mod_autoindex.html#addiconbytype">AddIconByType</a></code>,
455 <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_autoindex.html#fancyindexing">FancyIndexing</a></code>, <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>,
461 Allow use of the directives controlling host access (<code class="directive"><a href="../mod/mod_authz_host.html#allow">Allow</a></code>, <code class="directive"><a href="../mod/mod_authz_host.html#deny">Deny</a></code> and <code class="directive"><a href="../mod/mod_authz_host.html#order">Order</a></code>).</dd>
463 <dt>Options[=<var>Option</var>,...]</dt>
466 Allow use of the directives controlling specific directory
467 features (<code class="directive"><a href="#options">Options</a></code> and
468 <code class="directive"><a href="../mod/mod_include.html#xbithack">XBitHack</a></code>).
469 An equal sign may be given followed by a comma (but no spaces)
470 separated lists of options that may be set using the <code class="directive"><a href="#options">Options</a></code> command.</dd>
475 <div class="example"><p><code>
476 AllowOverride AuthConfig Indexes
479 <p>In the example above all directives that are neither in the group
480 <code>AuthConfig</code> nor <code>Indexes</code> cause an internal
483 <div class="note"><p>For security and performance reasons, do not set
484 <code>AllowOverride</code> to anything other than <code>None</code>
485 in your <code><Directory /></code> block. Instead, find (or
486 create) the <code><Directory></code> block that refers to the
487 directory where you're actually planning to place a
488 <code>.htaccess</code> file.</p>
493 <li><code class="directive"><a href="#accessfilename">AccessFileName</a></code></li>
494 <li><a href="../configuring.html">Configuration Files</a></li>
495 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
498 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
499 <div class="directive-section"><h2><a name="CGIMapExtension" id="CGIMapExtension">CGIMapExtension</a> <a name="cgimapextension" id="cgimapextension">Directive</a></h2>
500 <table class="directive">
501 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
503 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CGIMapExtension <var>cgi-path</var> <var>.extension</var></code></td></tr>
504 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
505 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
506 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
507 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
508 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>NetWare only</td></tr>
510 <p>This directive is used to control how Apache httpd finds the
511 interpreter used to run CGI scripts. For example, setting
512 <code>CGIMapExtension sys:\foo.nlm .foo</code> will
513 cause all CGI script files with a <code>.foo</code> extension to
514 be passed to the FOO interpreter.</p>
517 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
518 <div class="directive-section"><h2><a name="ContentDigest" id="ContentDigest">ContentDigest</a> <a name="contentdigest" id="contentdigest">Directive</a></h2>
519 <table class="directive">
520 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables the generation of <code>Content-MD5</code> HTTP Response
522 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ContentDigest On|Off</code></td></tr>
523 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ContentDigest Off</code></td></tr>
524 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
525 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
526 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
527 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
529 <p>This directive enables the generation of
530 <code>Content-MD5</code> headers as defined in RFC1864
531 respectively RFC2616.</p>
533 <p>MD5 is an algorithm for computing a "message digest"
534 (sometimes called "fingerprint") of arbitrary-length data, with
535 a high degree of confidence that any alterations in the data
536 will be reflected in alterations in the message digest.</p>
538 <p>The <code>Content-MD5</code> header provides an end-to-end
539 message integrity check (MIC) of the entity-body. A proxy or
540 client may check this header for detecting accidental
541 modification of the entity-body in transit. Example header:</p>
543 <div class="example"><p><code>
544 Content-MD5: AuLb7Dp1rqtRtxz2m9kRpA==
547 <p>Note that this can cause performance problems on your server
548 since the message digest is computed on every request (the
549 values are not cached).</p>
551 <p><code>Content-MD5</code> is only sent for documents served
552 by the <code class="module"><a href="../mod/core.html">core</a></code>, and not by any module. For example,
553 SSI documents, output from CGI scripts, and byte range responses
554 do not have this header.</p>
557 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
558 <div class="directive-section"><h2><a name="DefaultType" id="DefaultType">DefaultType</a> <a name="defaulttype" id="defaulttype">Directive</a></h2>
559 <table class="directive">
560 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>This directive has no effect other than to emit warnings
561 if the value is not <code>none</code>. In prior versions, DefaultType
562 would specify a default media type to assign to response content for
563 which no other media type configuration could be found.
565 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultType <var>media-type|none</var></code></td></tr>
566 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultType none</code></td></tr>
567 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
568 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
569 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
570 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
571 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>The argument <code>none</code> is available in Apache httpd 2.2.7 and later. All other choices are DISABLED for 2.3.x and later.</td></tr>
573 <p>This directive has been disabled. For backwards compatibility
574 of configuration files, it may be specified with the value
575 <code>none</code>, meaning no default media type. For example:</p>
577 <div class="example"><p><code>
581 <p><code>DefaultType None</code> is only available in
582 httpd-2.2.7 and later.</p>
584 <p>Use the mime.types configuration file and the
585 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code> to configure media
586 type assignments via file extensions, or the
587 <code class="directive"><a href="#forcetype">ForceType</a></code> directive to configure
588 the media type for specific resources. Otherwise, the server will
589 send the response without a Content-Type header field and the
590 recipient may attempt to guess the media type.</p>
593 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
594 <div class="directive-section"><h2><a name="Define" id="Define">Define</a> <a name="define" id="define">Directive</a></h2>
595 <table class="directive">
596 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Define the existence of a variable</td></tr>
597 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Define <var>parameter-name</var></code></td></tr>
598 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
599 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
600 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
602 <p>Equivalent to passing the <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</p>
603 <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
604 <code>-D</code> arguments in any startup scripts.</p>
607 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
608 <div class="directive-section"><h2><a name="Directory" id="Directory"><Directory></a> <a name="directory" id="directory">Directive</a></h2>
609 <table class="directive">
610 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose a group of directives that apply only to the
611 named file-system directory, sub-directories, and their contents.</td></tr>
612 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Directory <var>directory-path</var>>
613 ... </Directory></code></td></tr>
614 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
615 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
616 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
618 <p><code class="directive"><Directory></code> and
619 <code></Directory></code> are used to enclose a group of
620 directives that will apply only to the named directory,
621 sub-directories of that directory, and the files within the respective
622 directories. Any directive that is allowed
623 in a directory context may be used. <var>Directory-path</var> is
624 either the full path to a directory, or a wild-card string using
625 Unix shell-style matching. In a wild-card string, <code>?</code> matches
626 any single character, and <code>*</code> matches any sequences of
627 characters. You may also use <code>[]</code> character ranges. None
628 of the wildcards match a `/' character, so <code><Directory
629 /*/public_html></code> will not match
630 <code>/home/user/public_html</code>, but <code><Directory
631 /home/*/public_html></code> will match. Example:</p>
633 <div class="example"><p><code>
634 <Directory /usr/local/httpd/htdocs><br />
635 <span class="indent">
636 Options Indexes FollowSymLinks<br />
642 <p>Be careful with the <var>directory-path</var> arguments:
643 They have to literally match the filesystem path which Apache httpd uses
644 to access the files. Directives applied to a particular
645 <code><Directory></code> will not apply to files accessed from
646 that same directory via a different path, such as via different symbolic
650 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular
651 expressions</a> can also be used, with the addition of the
652 <code>~</code> character. For example:</p>
654 <div class="example"><p><code>
655 <Directory ~ "^/www/.*/[0-9]{3}">
658 <p>would match directories in <code>/www/</code> that consisted of
661 <p>If multiple (non-regular expression) <code class="directive"><Directory></code> sections
662 match the directory (or one of its parents) containing a document,
663 then the directives are applied in the order of shortest match
664 first, interspersed with the directives from the <a href="#accessfilename">.htaccess</a> files. For example,
667 <div class="example"><p><code>
668 <Directory /><br />
669 <span class="indent">
670 AllowOverride None<br />
672 </Directory><br />
674 <Directory /home/><br />
675 <span class="indent">
676 AllowOverride FileInfo<br />
681 <p>for access to the document <code>/home/web/dir/doc.html</code>
685 <li>Apply directive <code>AllowOverride None</code>
686 (disabling <code>.htaccess</code> files).</li>
688 <li>Apply directive <code>AllowOverride FileInfo</code> (for
689 directory <code>/home</code>).</li>
691 <li>Apply any <code>FileInfo</code> directives in
692 <code>/home/.htaccess</code>, <code>/home/web/.htaccess</code> and
693 <code>/home/web/dir/.htaccess</code> in that order.</li>
696 <p>Regular expressions are not considered until after all of the
697 normal sections have been applied. Then all of the regular
698 expressions are tested in the order they appeared in the
699 configuration file. For example, with</p>
701 <div class="example"><p><code>
702 <Directory ~ abc$><br />
703 <span class="indent">
704 # ... directives here ...<br />
709 <p>the regular expression section won't be considered until after
710 all normal <code class="directive"><Directory></code>s and
711 <code>.htaccess</code> files have been applied. Then the regular
712 expression will match on <code>/home/abc/public_html/abc</code> and
713 the corresponding <code class="directive"><Directory></code> will
716 <p><strong>Note that the default access for
717 <code><Directory /></code> is <code>Allow from All</code>.
718 This means that Apache httpd will serve any file mapped from an URL. It is
719 recommended that you change this with a block such
722 <div class="example"><p><code>
723 <Directory /><br />
724 <span class="indent">
725 Order Deny,Allow<br />
731 <p><strong>and then override this for directories you
732 <em>want</em> accessible. See the <a href="../misc/security_tips.html">Security Tips</a> page for more
733 details.</strong></p>
735 <p>The directory sections occur in the <code>httpd.conf</code> file.
736 <code class="directive"><Directory></code> directives
737 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>
741 <li><a href="../sections.html">How <Directory>,
742 <Location> and <Files> sections work</a> for an
743 explanation of how these different sections are combined when a
744 request is received</li>
747 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
748 <div class="directive-section"><h2><a name="DirectoryMatch" id="DirectoryMatch"><DirectoryMatch></a> <a name="directorymatch" id="directorymatch">Directive</a></h2>
749 <table class="directive">
750 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose directives that apply to
751 the contents of file-system directories matching a regular expression.</td></tr>
752 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><DirectoryMatch <var>regex</var>>
753 ... </DirectoryMatch></code></td></tr>
754 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
755 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
756 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
758 <p><code class="directive"><DirectoryMatch></code> and
759 <code></DirectoryMatch></code> are used to enclose a group
760 of directives which will apply only to the named directory (and the files within),
761 the same as <code class="directive"><a href="#directory"><Directory></a></code>.
762 However, it takes as an argument a
763 <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>. For example:</p>
765 <div class="example"><p><code>
766 <DirectoryMatch "^/www/(.+/)?[0-9]{3}">
769 <p>would match directories in <code>/www/</code> that consisted of three
772 <div class="note"><h3>Compatability</h3>
773 Prior to 2.3.9, this directive implicitly applied to sub-directories
774 (like <code class="directive"><a href="#directory"><Directory></a></code>) and
775 could not match the end of line symbol ($). In 2.3.9 and later,
776 only directories that match the expression are affected by the enclosed
780 <div class="note"><h3>Trailing Slash</h3>
781 This directive applies to requests for directories that may or may
782 not end in a trailing slash, so expressions that are anchored to the
783 end of line ($) must be written with care.
788 <li><code class="directive"><a href="#directory"><Directory></a></code> for
789 a description of how regular expressions are mixed in with normal
790 <code class="directive"><Directory></code>s</li>
791 <li><a href="../sections.html">How <Directory>, <Location> and
792 <Files> sections work</a> for an explanation of how these different
793 sections are combined when a request is received</li>
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="DocumentRoot" id="DocumentRoot">DocumentRoot</a> <a name="documentroot" id="documentroot">Directive</a></h2>
798 <table class="directive">
799 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory that forms the main document tree visible
800 from the web</td></tr>
801 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DocumentRoot <var>directory-path</var></code></td></tr>
802 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DocumentRoot /usr/local/apache/htdocs</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>This directive sets the directory from which <code class="program"><a href="../programs/httpd.html">httpd</a></code>
808 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
809 path from the requested URL to the document root to make the
810 path to the document. Example:</p>
812 <div class="example"><p><code>
813 DocumentRoot /usr/web
817 <code>http://www.my.host.com/index.html</code> refers to
818 <code>/usr/web/index.html</code>. If the <var>directory-path</var> is
819 not absolute then it is assumed to be relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
821 <p>The <code class="directive">DocumentRoot</code> should be specified without
822 a trailing slash.</p>
826 <li><a href="../urlmapping.html#documentroot">Mapping URLs to Filesystem
830 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
831 <div class="directive-section"><h2><a name="EnableMMAP" id="EnableMMAP">EnableMMAP</a> <a name="enablemmap" id="enablemmap">Directive</a></h2>
832 <table class="directive">
833 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use memory-mapping to read files during delivery</td></tr>
834 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableMMAP On|Off</code></td></tr>
835 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableMMAP On</code></td></tr>
836 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
837 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
838 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
839 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
841 <p>This directive controls whether the <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use
842 memory-mapping if it needs to read the contents of a file during
843 delivery. By default, when the handling of a request requires
844 access to the data within a file -- for example, when delivering a
845 server-parsed file using <code class="module"><a href="../mod/mod_include.html">mod_include</a></code> -- Apache httpd
846 memory-maps the file if the OS supports it.</p>
848 <p>This memory-mapping sometimes yields a performance improvement.
849 But in some environments, it is better to disable the memory-mapping
850 to prevent operational problems:</p>
853 <li>On some multiprocessor systems, memory-mapping can reduce the
854 performance of the <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</li>
855 <li>Deleting or truncating a file while <code class="program"><a href="../programs/httpd.html">httpd</a></code>
856 has it memory-mapped can cause <code class="program"><a href="../programs/httpd.html">httpd</a></code> to
857 crash with a segmentation fault.
861 <p>For server configurations that are vulnerable to these problems,
862 you should disable memory-mapping of delivered files by specifying:</p>
864 <div class="example"><p><code>
868 <p>For NFS mounted files, this feature may be disabled explicitly for
869 the offending files by specifying:</p>
871 <div class="example"><p><code>
872 <Directory "/path-to-nfs-files">
873 <span class="indent">
880 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
881 <div class="directive-section"><h2><a name="EnableSendfile" id="EnableSendfile">EnableSendfile</a> <a name="enablesendfile" id="enablesendfile">Directive</a></h2>
882 <table class="directive">
883 <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>
884 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableSendfile On|Off</code></td></tr>
885 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableSendfile Off</code></td></tr>
886 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
887 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
888 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
889 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
890 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in version 2.0.44 and later. Default changed to Off in
891 version 2.3.9.</td></tr>
893 <p>This directive controls whether <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use the
894 sendfile support from the kernel to transmit file contents to the client.
895 By default, when the handling of a request requires no access
896 to the data within a file -- for example, when delivering a
897 static file -- Apache httpd uses sendfile to deliver the file contents
898 without ever reading the file if the OS supports it.</p>
900 <p>This sendfile mechanism avoids separate read and send operations,
901 and buffer allocations. But on some platforms or within some
902 filesystems, it is better to disable this feature to avoid
903 operational problems:</p>
906 <li>Some platforms may have broken sendfile support that the build
907 system did not detect, especially if the binaries were built on
908 another box and moved to such a machine with broken sendfile
910 <li>On Linux the use of sendfile triggers TCP-checksum
911 offloading bugs on certain networking cards when using IPv6.</li>
912 <li>On Linux on Itanium, sendfile may be unable to handle files
913 over 2GB in size.</li>
914 <li>With a network-mounted <code class="directive"><a href="#documentroot">DocumentRoot</a></code> (e.g., NFS, SMB, CIFS, FUSE),
915 the kernel may be unable to serve the network file through
919 <p>For server configurations that are not vulnerable to these problems,
920 you may enable this feature by specifying:</p>
922 <div class="example"><p><code>
926 <p>For network mounted files, this feature may be disabled explicitly
927 for the offending files by specifying:</p>
929 <div class="example"><p><code>
930 <Directory "/path-to-nfs-files">
931 <span class="indent">
936 <p>Please note that the per-directory and .htaccess configuration
937 of <code class="directive">EnableSendfile</code> is not supported by
938 <code class="module"><a href="../mod/mod_cache_disk.html">mod_cache_disk</a></code>.
939 Only global definition of <code class="directive">EnableSendfile</code>
940 is taken into account by the module.
944 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
945 <div class="directive-section"><h2><a name="Error" id="Error">Error</a> <a name="error" id="error">Directive</a></h2>
946 <table class="directive">
947 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Abort configuration parsing with a custom error message</td></tr>
948 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Error <var>message</var></code></td></tr>
949 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
950 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
951 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
952 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.3.9 and later</td></tr>
954 <p>If an error can be detected within the configuration, this
955 directive can be used to generate a custom error message, and halt
956 configuration parsing. The typical use is for reporting required
957 modules which are missing from the configuration.</p>
959 <div class="example"><h3>Example</h3><p><code>
960 # ensure that mod_include is loaded<br />
961 <IfModule !include_module><br />
962 Error mod_include is required by mod_foo. Load it with LoadModule.<br />
963 </IfModule><br />
965 # ensure that exactly one of SSL,NOSSL is defined<br />
966 <IfDefine SSL><br />
967 <IfDefine NOSSL><br />
968 Error Both SSL and NOSSL are defined. Define only one of them.<br />
969 </IfDefine><br />
970 </IfDefine><br />
971 <IfDefine !SSL><br />
972 <IfDefine !NOSSL><br />
973 Error Either SSL or NOSSL must be defined.<br />
974 </IfDefine><br />
975 </IfDefine><br />
980 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
981 <div class="directive-section"><h2><a name="ErrorDocument" id="ErrorDocument">ErrorDocument</a> <a name="errordocument" id="errordocument">Directive</a></h2>
982 <table class="directive">
983 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>What the server will return to the client
984 in case of an error</td></tr>
985 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ErrorDocument <var>error-code</var> <var>document</var></code></td></tr>
986 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
987 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
988 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
989 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
991 <p>In the event of a problem or error, Apache httpd can be configured
992 to do one of four things,</p>
995 <li>output a simple hardcoded error message</li>
997 <li>output a customized message</li>
999 <li>redirect to a local <var>URL-path</var> to handle the
1002 <li>redirect to an external <var>URL</var> to handle the
1006 <p>The first option is the default, while options 2-4 are
1007 configured using the <code class="directive">ErrorDocument</code>
1008 directive, which is followed by the HTTP response code and a URL
1009 or a message. Apache httpd will sometimes offer additional information
1010 regarding the problem/error.</p>
1012 <p>URLs can begin with a slash (/) for local web-paths (relative
1013 to the <code class="directive"><a href="#documentroot">DocumentRoot</a></code>), or be a
1014 full URL which the client can resolve. Alternatively, a message
1015 can be provided to be displayed by the browser. Examples:</p>
1017 <div class="example"><p><code>
1018 ErrorDocument 500 http://foo.example.com/cgi-bin/tester<br />
1019 ErrorDocument 404 /cgi-bin/bad_urls.pl<br />
1020 ErrorDocument 401 /subscription_info.html<br />
1021 ErrorDocument 403 "Sorry can't allow you access today"
1024 <p>Additionally, the special value <code>default</code> can be used
1025 to specify Apache httpd's simple hardcoded message. While not required
1026 under normal circumstances, <code>default</code> will restore
1027 Apache httpd's simple hardcoded message for configurations that would
1028 otherwise inherit an existing <code class="directive">ErrorDocument</code>.</p>
1030 <div class="example"><p><code>
1031 ErrorDocument 404 /cgi-bin/bad_urls.pl<br /><br />
1032 <Directory /web/docs><br />
1033 <span class="indent">
1034 ErrorDocument 404 default<br />
1039 <p>Note that when you specify an <code class="directive">ErrorDocument</code>
1040 that points to a remote URL (ie. anything with a method such as
1041 <code>http</code> in front of it), Apache HTTP Server will send a redirect to the
1042 client to tell it where to find the document, even if the
1043 document ends up being on the same server. This has several
1044 implications, the most important being that the client will not
1045 receive the original error status code, but instead will
1046 receive a redirect status code. This in turn can confuse web
1047 robots and other clients which try to determine if a URL is
1048 valid using the status code. In addition, if you use a remote
1049 URL in an <code>ErrorDocument 401</code>, the client will not
1050 know to prompt the user for a password since it will not
1051 receive the 401 status code. Therefore, <strong>if you use an
1052 <code>ErrorDocument 401</code> directive then it must refer to a local
1053 document.</strong></p>
1055 <p>Microsoft Internet Explorer (MSIE) will by default ignore
1056 server-generated error messages when they are "too small" and substitute
1057 its own "friendly" error messages. The size threshold varies depending on
1058 the type of error, but in general, if you make your error document
1059 greater than 512 bytes, then MSIE will show the server-generated
1060 error rather than masking it. More information is available in
1061 Microsoft Knowledge Base article <a href="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q294807">Q294807</a>.</p>
1063 <p>Although most error messages can be overriden, there are certain
1064 circumstances where the internal messages are used regardless of the
1065 setting of <code class="directive"><a href="#errordocument">ErrorDocument</a></code>. In
1066 particular, if a malformed request is detected, normal request processing
1067 will be immediately halted and the internal error message returned.
1068 This is necessary to guard against security problems caused by
1071 <p>If you are using mod_proxy, you may wish to enable
1072 <code class="directive"><a href="../mod/mod_proxy.html#proxyerroroverride">ProxyErrorOverride</a></code> so that you can provide
1073 custom error messages on behalf of your Origin servers. If you don't enable ProxyErrorOverride,
1074 Apache httpd will not generate custom error documents for proxied content.</p>
1078 <li><a href="../custom-error.html">documentation of
1079 customizable responses</a></li>
1082 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1083 <div class="directive-section"><h2><a name="ErrorLog" id="ErrorLog">ErrorLog</a> <a name="errorlog" id="errorlog">Directive</a></h2>
1084 <table class="directive">
1085 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Location where the server will log errors</td></tr>
1086 <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>
1087 <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>
1088 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1089 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1090 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1092 <p>The <code class="directive">ErrorLog</code> directive sets the name of
1093 the file to which the server will log any errors it encounters. If
1094 the <var>file-path</var> is not absolute then it is assumed to be
1095 relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1097 <div class="example"><h3>Example</h3><p><code>
1098 ErrorLog /var/log/httpd/error_log
1101 <p>If the <var>file-path</var>
1102 begins with a pipe character "<code>|</code>" then it is assumed to be a
1103 command to spawn to handle the error log.</p>
1105 <div class="example"><h3>Example</h3><p><code>
1106 ErrorLog "|/usr/local/bin/httpd_errors"
1109 <p>See the notes on <a href="../logs.html#piped">piped logs</a> for
1110 more information.</p>
1112 <p>Using <code>syslog</code> instead of a filename enables logging
1113 via syslogd(8) if the system supports it. The default is to use
1114 syslog facility <code>local7</code>, but you can override this by
1115 using the <code>syslog:<var>facility</var></code> syntax where
1116 <var>facility</var> can be one of the names usually documented in
1117 syslog(1). The facility is effectively global, and if it is changed
1118 in individual virtual hosts, the final facility specified affects the
1121 <div class="example"><h3>Example</h3><p><code>
1122 ErrorLog syslog:user
1125 <p>SECURITY: See the <a href="../misc/security_tips.html#serverroot">security tips</a>
1126 document for details on why your security could be compromised
1127 if the directory where log files are stored is writable by
1128 anyone other than the user that starts the server.</p>
1129 <div class="warning"><h3>Note</h3>
1130 <p>When entering a file path on non-Unix platforms, care should be taken
1131 to make sure that only forward slashes are used even though the platform
1132 may allow the use of back slashes. In general it is a good idea to always
1133 use forward slashes throughout the configuration files.</p>
1138 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1139 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1142 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1143 <div class="directive-section"><h2><a name="ErrorLogFormat" id="ErrorLogFormat">ErrorLogFormat</a> <a name="errorlogformat" id="errorlogformat">Directive</a></h2>
1144 <table class="directive">
1145 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Format specification for error log entries</td></tr>
1146 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code> ErrorLog [connection|request] <var>format</var></code></td></tr>
1147 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1148 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1149 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1150 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.3.9 and later</td></tr>
1152 <p><code class="directive">ErrorLogFormat</code> allows to specify what
1153 supplementary information is logged in the error log in addition to the
1154 actual log message.</p>
1156 <div class="example"><h3>Simple example</h3><p><code>
1157 ErrorLogFormat "[%t] [%l] [pid %P] %F: %E: [client %a] %M"
1160 <p>Specifying <code>connection</code> or <code>request</code> as first
1161 paramter allows to specify additional formats, causing additional
1162 information to be logged when the first message is logged for a specific
1163 connection or request, respectivly. This additional information is only
1164 logged once per connection/request. If a connection or request is processed
1165 without causing any log message, the additional information is not logged
1168 <p>It can happen that some format string items do not produce output. For
1169 example, the Referer header is only present if the log message is
1170 associated to a request and the log message happens at a time when the
1171 Referer header has already been read from the client. If no output is
1172 produced, the default behaviour is to delete everything from the preceeding
1173 space character to the next space character. This means the log line is
1174 implicitly divided into fields on non-whitespace to whitespace transitions.
1175 If a format string item does not produce output, the whole field is
1176 ommitted. For example, if the remote address <code>%a</code> in the log
1177 format <code>[%t] [%l] [%a] %M </code> is not available, the surrounding
1178 brackets are not logged either. Space characters can be escaped with a
1179 backslash to prevent them from delimiting a field. The combination '% '
1180 (percent space) is a zero-witdh field delimiter that does not produce any
1183 <p>The above behaviour can be changed by adding modifiers to the format
1184 string item. A <code>-</code> (minus) modifier causes a minus to be logged if the
1185 respective item does not produce any output. In once-per-connection/request
1186 formats, it is also possible to use the <code>+</code> (plus) modifier. If an
1187 item with the plus modifier does not produce any output, the whole line is
1190 <p>A number as modifier can be used to assign a log severity level to a
1191 format item. The item will only be logged if the severity of the log
1192 message is not higher than the specified log severity level. The number can
1193 range from 1 (alert) over 4 (warn) and 7 (debug) to 15 (trace8).</p>
1195 <p>Some format string items accept additional parameters in braces.</p>
1197 <table class="bordered"><tr class="header"><th>Format String</th> <th>Description</th></tr>
1198 <tr><td><code>%%</code></td>
1199 <td>The percent sign</td></tr>
1200 <tr class="odd"><td><code>%...a</code></td>
1201 <td>Remote IP-address and port</td></tr>
1202 <tr><td><code>%...A</code></td>
1203 <td>Local IP-address and port</td></tr>
1204 <tr class="odd"><td><code>%...{name}e</code></td>
1205 <td>Request environment variable <code>name</code></td></tr>
1206 <tr><td><code>%...E</code></td>
1207 <td>APR/OS error status code and string</td></tr>
1208 <tr class="odd"><td><code>%...F</code></td>
1209 <td>Source file name and line number of the log call</td></tr>
1210 <tr><td><code>%...{name}i</code></td>
1211 <td>Request header <code>name</code></td></tr>
1212 <tr class="odd"><td><code>%...k</code></td>
1213 <td>Number of keep-alive requests on this connection</td></tr>
1214 <tr><td><code>%...l</code></td>
1215 <td>Loglevel of the message</td></tr>
1216 <tr class="odd"><td><code>%...L</code></td>
1217 <td>Log ID of the request</td></tr>
1218 <tr><td><code>%...{c}L</code></td>
1219 <td>Log ID of the connection</td></tr>
1220 <tr class="odd"><td><code>%...{C}L</code></td>
1221 <td>Log ID of the connection if used in connection scope, empty otherwise</td></tr>
1222 <tr><td><code>%...m</code></td>
1223 <td>Name of the module logging the message</td></tr>
1224 <tr class="odd"><td><code>%M</code></td>
1225 <td>The actual log message</td></tr>
1226 <tr><td><code>%...{name}n</code></td>
1227 <td>Request note <code>name</code></td></tr>
1228 <tr class="odd"><td><code>%...P</code></td>
1229 <td>Process ID of current process</td></tr>
1230 <tr><td><code>%...T</code></td>
1231 <td>Thread ID of current thread</td></tr>
1232 <tr class="odd"><td><code>%...t</code></td>
1233 <td>The current time</td></tr>
1234 <tr><td><code>%...{u}t</code></td>
1235 <td>The current time including micro-seconds</td></tr>
1236 <tr class="odd"><td><code>%...{cu}t</code></td>
1237 <td>The current time in compact ISO 8601 format, including
1238 micro-seconds</td></tr>
1239 <tr><td><code>%...v</code></td>
1240 <td>The canonical <code class="directive"><a href="#servername">ServerName</a></code>
1241 of the current server.</td></tr>
1242 <tr class="odd"><td><code>%...V</code></td>
1243 <td>The server name of the server serving the request according to the
1244 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code>
1246 <tr><td><code>\ </code> (backslash space)</td>
1247 <td>Non-field delimiting space</td></tr>
1248 <tr class="odd"><td><code>% </code> (percent space)</td>
1249 <td>Field delimiter (no output)</td></tr>
1252 <p>The log ID format <code>%L</code> produces a unique id for a connection
1253 or request. This can be used to correlate which log lines belong to the
1254 same connection or request, which request happens on which connection.
1255 A <code>%L</code> format string is also available in
1256 <code class="module"><a href="../mod/mod_log_config.html">mod_log_config</a></code>, to allow to correlate access log entries
1257 with error log lines. If <code class="module"><a href="../mod/mod_unique_id.html">mod_unique_id</a></code> is loaded, its
1258 unique id will be used as log ID for requests.</p>
1260 <div class="example"><h3>Example (somewhat similar to default format)</h3><p><code>
1261 ErrorLogFormat "[%{u}t] [%-m:%l] [pid %P] %7F: %E: [client\ %a]
1262 %M% ,\ referer\ %{Referer}i"
1265 <div class="example"><h3>Example (similar to the 2.2.x format)</h3><p><code>
1266 ErrorLogFormat "[%t] [%l] %7F: %E: [client\ %a]
1267 %M% ,\ referer\ %{Referer}i"
1270 <div class="example"><h3>Advanced example with request/connection log IDs</h3><p><code>
1271 ErrorLogFormat "[%{uc}t] [%-m:%-l] [R:%L] [C:%{C}L] %7F: %E: %M"<br />
1272 ErrorLogFormat request "[%{uc}t] [R:%L] Request %k on C:%{c}L pid:%P tid:%T"<br />
1273 ErrorLogFormat request "[%{uc}t] [R:%L] UA:'%+{User-Agent}i'"<br />
1274 ErrorLogFormat request "[%{uc}t] [R:%L] Referer:'%+{Referer}i'"<br />
1275 ErrorLogFormat connection "[%{uc}t] [C:%{c}L] local\ %a remote\ %A"<br />
1281 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
1282 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1283 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1286 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1287 <div class="directive-section"><h2><a name="ExtendedStatus" id="ExtendedStatus">ExtendedStatus</a> <a name="extendedstatus" id="extendedstatus">Directive</a></h2>
1288 <table class="directive">
1289 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Keep track of extended status information for each
1291 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ExtendedStatus On|Off</code></td></tr>
1292 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ExtendedStatus Off[*]</code></td></tr>
1293 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
1294 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1295 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1297 <p>This option tracks additional data per worker about the
1298 currently executing request, and a utilization summary; you
1299 can see these variables during runtime by configuring
1300 <code class="module"><a href="../mod/mod_status.html">mod_status</a></code>. Note that other modules may
1301 rely on this scoreboard.</p>
1303 <p>This setting applies to the entire server, and cannot be
1304 enabled or disabled on a virtualhost-by-virtualhost basis.
1305 The collection of extended status information can slow down
1306 the server. Also note that this setting cannot be changed
1307 during a graceful restart.</p>
1310 <p>Note that loading <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> will change
1311 the default behavior to ExtendedStatus On, while other
1312 third party modules may do the same. Such modules rely on
1313 collecting detailed information about the state of all workers.
1314 The default is changed by <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> beginning
1315 with version 2.3.6; the previous default was always Off.</p>
1320 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1321 <div class="directive-section"><h2><a name="FileETag" id="FileETag">FileETag</a> <a name="fileetag" id="fileetag">Directive</a></h2>
1322 <table class="directive">
1323 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>File attributes used to create the ETag
1324 HTTP response header for static files</td></tr>
1325 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>FileETag <var>component</var> ...</code></td></tr>
1326 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>FileETag INode MTime Size</code></td></tr>
1327 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1328 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1329 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1330 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1333 The <code class="directive">FileETag</code> directive configures the file
1334 attributes that are used to create the <code>ETag</code> (entity
1335 tag) response header field when the document is based on a static file.
1336 (The <code>ETag</code> value is used in cache management to save
1337 network bandwidth.) The
1338 <code class="directive">FileETag</code> directive allows you to choose
1339 which of these -- if any -- should be used. The recognized keywords are:
1343 <dt><strong>INode</strong></dt>
1344 <dd>The file's i-node number will be included in the calculation</dd>
1345 <dt><strong>MTime</strong></dt>
1346 <dd>The date and time the file was last modified will be included</dd>
1347 <dt><strong>Size</strong></dt>
1348 <dd>The number of bytes in the file will be included</dd>
1349 <dt><strong>All</strong></dt>
1350 <dd>All available fields will be used. This is equivalent to:
1351 <div class="example"><p><code>FileETag INode MTime Size</code></p></div></dd>
1352 <dt><strong>None</strong></dt>
1353 <dd>If a document is file-based, no <code>ETag</code> field will be
1354 included in the response</dd>
1357 <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
1358 keywords may be prefixed with either <code>+</code> or <code>-</code>,
1359 which allow changes to be made to the default setting inherited
1360 from a broader scope. Any keyword appearing without such a prefix
1361 immediately and completely cancels the inherited setting.</p>
1363 <p>If a directory's configuration includes
1364 <code>FileETag INode MTime Size</code>, and a
1365 subdirectory's includes <code>FileETag -INode</code>,
1366 the setting for that subdirectory (which will be inherited by
1367 any sub-subdirectories that don't override it) will be equivalent to
1368 <code>FileETag MTime Size</code>.</p>
1369 <div class="warning"><h3>Warning</h3>
1370 Do not change the default for directories or locations that have WebDAV
1371 enabled and use <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> as a storage provider.
1372 <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> uses <code>INode MTime Size</code>
1373 as a fixed format for <code>ETag</code> comparisons on conditional requests.
1374 These conditional requests will break if the <code>ETag</code> format is
1375 changed via <code class="directive">FileETag</code>.
1377 <div class="note"><h3>Server Side Includes</h3>
1378 An ETag is not generated for responses parsed by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>,
1379 since the response entity can change without a change of the INode, MTime, or Size
1380 of the static file with embedded SSI directives.
1385 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1386 <div class="directive-section"><h2><a name="Files" id="Files"><Files></a> <a name="files" id="files">Directive</a></h2>
1387 <table class="directive">
1388 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to matched
1390 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Files <var>filename</var>> ... </Files></code></td></tr>
1391 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1392 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1393 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1394 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1396 <p>The <code class="directive"><Files></code> directive
1397 limits the scope of the enclosed directives by filename. It is comparable
1398 to the <code class="directive"><a href="#directory"><Directory></a></code>
1399 and <code class="directive"><a href="#location"><Location></a></code>
1400 directives. It should be matched with a <code></Files></code>
1401 directive. The directives given within this section will be applied to
1402 any object with a basename (last component of filename) matching the
1403 specified filename. <code class="directive"><Files></code>
1404 sections are processed in the order they appear in the
1405 configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
1406 <code>.htaccess</code> files are read, but before <code class="directive"><a href="#location"><Location></a></code> sections. Note
1407 that <code class="directive"><Files></code> can be nested
1408 inside <code class="directive"><a href="#directory"><Directory></a></code> sections to restrict the
1409 portion of the filesystem they apply to.</p>
1411 <p>The <var>filename</var> argument should include a filename, or
1412 a wild-card string, where <code>?</code> matches any single character,
1413 and <code>*</code> matches any sequences of characters.
1414 <a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
1415 can also be used, with the addition of the
1416 <code>~</code> character. For example:</p>
1418 <div class="example"><p><code>
1419 <Files ~ "\.(gif|jpe?g|png)$">
1422 <p>would match most common Internet graphics formats. <code class="directive"><a href="#filesmatch"><FilesMatch></a></code> is preferred,
1425 <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
1426 <code>.htaccess</code> files. This allows users to control access to
1427 their own files, at a file-by-file level.</p>
1432 <li><a href="../sections.html">How <Directory>, <Location>
1433 and <Files> sections work</a> for an explanation of how these
1434 different sections are combined when a request is received</li>
1437 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1438 <div class="directive-section"><h2><a name="FilesMatch" id="FilesMatch"><FilesMatch></a> <a name="filesmatch" id="filesmatch">Directive</a></h2>
1439 <table class="directive">
1440 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to regular-expression matched
1442 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><FilesMatch <var>regex</var>> ... </FilesMatch></code></td></tr>
1443 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1444 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1445 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1446 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1448 <p>The <code class="directive"><FilesMatch></code> directive
1449 limits the scope of the enclosed directives by filename, just as the
1450 <code class="directive"><a href="#files"><Files></a></code> directive
1451 does. However, it accepts a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular
1452 expression</a>. For example:</p>
1454 <div class="example"><p><code>
1455 <FilesMatch "\.(gif|jpe?g|png)$">
1458 <p>would match most common Internet graphics formats.</p>
1462 <li><a href="../sections.html">How <Directory>, <Location>
1463 and <Files> sections work</a> for an explanation of how these
1464 different sections are combined when a request is received</li>
1467 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1468 <div class="directive-section"><h2><a name="ForceType" id="ForceType">ForceType</a> <a name="forcetype" id="forcetype">Directive</a></h2>
1469 <table class="directive">
1470 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be served with the specified
1471 media type in the HTTP Content-Type header field</td></tr>
1472 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ForceType <var>media-type</var>|None</code></td></tr>
1473 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
1474 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1475 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1476 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1477 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Moved to the core in Apache httpd 2.0</td></tr>
1479 <p>When placed into an <code>.htaccess</code> file or a
1480 <code class="directive"><a href="#directory"><Directory></a></code>, or
1481 <code class="directive"><a href="#location"><Location></a></code> or
1482 <code class="directive"><a href="#files"><Files></a></code>
1483 section, this directive forces all matching files to be served
1484 with the content type identification given by
1485 <var>media-type</var>. For example, if you had a directory full of
1486 GIF files, but did not want to label them all with <code>.gif</code>,
1487 you might want to use:</p>
1489 <div class="example"><p><code>
1493 <p>Note that this directive overrides other indirect media type
1494 associations defined in mime.types or via the
1495 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code>.</p>
1497 <p>You can also override more general
1498 <code class="directive">ForceType</code> settings
1499 by using the value of <code>None</code>:</p>
1501 <div class="example"><p><code>
1502 # force all files to be image/gif:<br />
1503 <Location /images><br />
1504 <span class="indent">
1505 ForceType image/gif<br />
1507 </Location><br />
1509 # but normal mime-type associations here:<br />
1510 <Location /images/mixed><br />
1511 <span class="indent">
1512 ForceType None<br />
1517 <p>This directive primarily overrides the content types generated for
1518 static files served out of the filesystem. For resources other than
1519 static files, where the generator of the response typically specifies
1520 a Content-Type, this directive has no effect.</p>
1524 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1525 <div class="directive-section"><h2><a name="GprofDir" id="GprofDir">GprofDir</a> <a name="gprofdir" id="gprofdir">Directive</a></h2>
1526 <table class="directive">
1527 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory to write gmon.out profiling data to. </td></tr>
1528 <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>
1529 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1530 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1531 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1533 <p>When the server has been compiled with gprof profiling suppport,
1534 <code class="directive">GprofDir</code> causes <code>gmon.out</code> files to
1535 be written to the specified directory when the process exits. If the
1536 argument ends with a percent symbol ('%'), subdirectories are created
1537 for each process id.</p>
1539 <p>This directive currently only works with the <code class="module"><a href="../mod/prefork.html">prefork</a></code>
1543 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1544 <div class="directive-section"><h2><a name="HostnameLookups" id="HostnameLookups">HostnameLookups</a> <a name="hostnamelookups" id="hostnamelookups">Directive</a></h2>
1545 <table class="directive">
1546 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables DNS lookups on client IP addresses</td></tr>
1547 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>HostnameLookups On|Off|Double</code></td></tr>
1548 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>HostnameLookups Off</code></td></tr>
1549 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1550 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1551 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1553 <p>This directive enables DNS lookups so that host names can be
1554 logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
1555 The value <code>Double</code> refers to doing double-reverse
1556 DNS lookup. That is, after a reverse lookup is performed, a forward
1557 lookup is then performed on that result. At least one of the IP
1558 addresses in the forward lookup must match the original
1559 address. (In "tcpwrappers" terminology this is called
1560 <code>PARANOID</code>.)</p>
1562 <p>Regardless of the setting, when <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code> is
1563 used for controlling access by hostname, a double reverse lookup
1564 will be performed. This is necessary for security. Note that the
1565 result of this double-reverse isn't generally available unless you
1566 set <code>HostnameLookups Double</code>. For example, if only
1567 <code>HostnameLookups On</code> and a request is made to an object
1568 that is protected by hostname restrictions, regardless of whether
1569 the double-reverse fails or not, CGIs will still be passed the
1570 single-reverse result in <code>REMOTE_HOST</code>.</p>
1572 <p>The default is <code>Off</code> in order to save the network
1573 traffic for those sites that don't truly need the reverse
1574 lookups done. It is also better for the end users because they
1575 don't have to suffer the extra latency that a lookup entails.
1576 Heavily loaded sites should leave this directive
1577 <code>Off</code>, since DNS lookups can take considerable
1578 amounts of time. The utility <code class="program"><a href="../programs/logresolve.html">logresolve</a></code>, compiled by
1579 default to the <code>bin</code> subdirectory of your installation
1580 directory, can be used to look up host names from logged IP addresses
1584 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1585 <div class="directive-section"><h2><a name="If" id="If"><If></a> <a name="if" id="if">Directive</a></h2>
1586 <table class="directive">
1587 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is
1588 satisfied by a request at runtime</td></tr>
1589 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><If <var>expression</var>> ... </If></code></td></tr>
1590 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1591 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1592 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1593 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1595 <p>The <code class="directive"><If></code> directive
1596 evaluates an expression at runtime, and applies the enclosed
1597 directives if and only if the expression evaluates to true.
1600 <div class="example"><p><code>
1601 <If "$req{Host} = ''">
1604 <p>would match HTTP/1.0 requests without a <var>Host:</var> header.</p>
1606 <p>You may compare the value of any variable in the request headers
1607 ($req), response headers ($resp) or environment ($env) in your
1610 <p>Apart from <code>=</code>, <code>If</code> can use the <code>IN</code>
1611 operator to compare if the expression is in a given range:</p>
1613 <div class="example"><p><code>
1614 <If %{REQUEST_METHOD} IN GET,HEAD,OPTIONS>
1620 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
1621 for a complete reference and more examples.</li>
1622 <li><a href="../sections.html">How <Directory>, <Location>,
1623 <Files> sections work</a> for an explanation of how these
1624 different sections are combined when a request is received.
1625 <code class="directive"><If></code> has the same precedence
1626 and usage as <code class="directive"><Files></code></li>
1629 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1630 <div class="directive-section"><h2><a name="IfDefine" id="IfDefine"><IfDefine></a> <a name="ifdefine" id="ifdefine">Directive</a></h2>
1631 <table class="directive">
1632 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that will be processed only
1633 if a test is true at startup</td></tr>
1634 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfDefine [!]<var>parameter-name</var>> ...
1635 </IfDefine></code></td></tr>
1636 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1637 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1638 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1639 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1641 <p>The <code><IfDefine <var>test</var>>...</IfDefine>
1642 </code> section is used to mark directives that are conditional. The
1643 directives within an <code class="directive"><IfDefine></code>
1644 section are only processed if the <var>test</var> is true. If <var>
1645 test</var> is false, everything between the start and end markers is
1648 <p>The <var>test</var> in the <code class="directive"><IfDefine></code> section directive can be one of two forms:</p>
1651 <li><var>parameter-name</var></li>
1653 <li><code>!</code><var>parameter-name</var></li>
1656 <p>In the former case, the directives between the start and end
1657 markers are only processed if the parameter named
1658 <var>parameter-name</var> is defined. The second format reverses
1659 the test, and only processes the directives if
1660 <var>parameter-name</var> is <strong>not</strong> defined.</p>
1662 <p>The <var>parameter-name</var> argument is a define as given on the
1663 <code class="program"><a href="../programs/httpd.html">httpd</a></code> command line via <code>-D<var>parameter</var>
1664 </code> at the time the server was started or by the <code class="directive"><a href="#define">Define</a></code> directive.</p>
1666 <p><code class="directive"><IfDefine></code> sections are
1667 nest-able, which can be used to implement simple
1668 multiple-parameter tests. Example:</p>
1670 <div class="example"><p><code>
1671 httpd -DReverseProxy -DUseCache -DMemCache ...<br />
1674 <IfDefine ReverseProxy><br />
1675 <span class="indent">
1676 LoadModule proxy_module modules/mod_proxy.so<br />
1677 LoadModule proxy_http_module modules/mod_proxy_http.so<br />
1678 <IfDefine UseCache><br />
1679 <span class="indent">
1680 LoadModule cache_module modules/mod_cache.so<br />
1681 <IfDefine MemCache><br />
1682 <span class="indent">
1683 LoadModule mem_cache_module modules/mod_mem_cache.so<br />
1685 </IfDefine><br />
1686 <IfDefine !MemCache><br />
1687 <span class="indent">
1688 LoadModule cache_disk_module modules/mod_cache_disk.so<br />
1698 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1699 <div class="directive-section"><h2><a name="IfModule" id="IfModule"><IfModule></a> <a name="ifmodule" id="ifmodule">Directive</a></h2>
1700 <table class="directive">
1701 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that are processed conditional on the
1702 presence or absence of a specific module</td></tr>
1703 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfModule [!]<var>module-file</var>|<var>module-identifier</var>> ...
1704 </IfModule></code></td></tr>
1705 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1706 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1707 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1708 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1709 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Module identifiers are available in version 2.1 and
1712 <p>The <code><IfModule <var>test</var>>...</IfModule></code>
1713 section is used to mark directives that are conditional on the presence of
1714 a specific module. The directives within an <code class="directive"><IfModule></code> section are only processed if the <var>test</var>
1715 is true. If <var>test</var> is false, everything between the start and
1716 end markers is ignored.</p>
1718 <p>The <var>test</var> in the <code class="directive"><IfModule></code> section directive can be one of two forms:</p>
1721 <li><var>module</var></li>
1723 <li>!<var>module</var></li>
1726 <p>In the former case, the directives between the start and end
1727 markers are only processed if the module named <var>module</var>
1728 is included in Apache httpd -- either compiled in or
1729 dynamically loaded using <code class="directive"><a href="../mod/mod_so.html#loadmodule">LoadModule</a></code>. The second format reverses the test,
1730 and only processes the directives if <var>module</var> is
1731 <strong>not</strong> included.</p>
1733 <p>The <var>module</var> argument can be either the module identifier or
1734 the file name of the module, at the time it was compiled. For example,
1735 <code>rewrite_module</code> is the identifier and
1736 <code>mod_rewrite.c</code> is the file name. If a module consists of
1737 several source files, use the name of the file containing the string
1738 <code>STANDARD20_MODULE_STUFF</code>.</p>
1740 <p><code class="directive"><IfModule></code> sections are
1741 nest-able, which can be used to implement simple multiple-module
1744 <div class="note">This section should only be used if you need to have one
1745 configuration file that works whether or not a specific module
1746 is available. In normal operation, directives need not be
1747 placed in <code class="directive"><IfModule></code>
1751 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1752 <div class="directive-section"><h2><a name="Include" id="Include">Include</a> <a name="include" id="include">Directive</a></h2>
1753 <table class="directive">
1754 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
1755 the server configuration files</td></tr>
1756 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Include [<var>optional</var>|<var>strict</var>] <var>file-path</var>|<var>directory-path</var>|<var>wildcard</var></code></td></tr>
1757 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1758 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1759 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1760 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Wildcard matching available in 2.0.41 and later, directory
1761 wildcard matching available in 2.3.6 and later</td></tr>
1763 <p>This directive allows inclusion of other configuration files
1764 from within the server configuration files.</p>
1766 <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used
1767 in the filename or directory parts of the path to include several files
1768 at once, in alphabetical order. In addition, if
1769 <code class="directive">Include</code> points to a directory, rather than a file,
1770 Apache httpd will read all files in that directory and any subdirectory.
1771 However, including entire directories is not recommended, because it is
1772 easy to accidentally leave temporary files in a directory that can cause
1773 <code class="program"><a href="../programs/httpd.html">httpd</a></code> to fail. Instead, we encourage you to use the
1774 wildcard syntax shown below, to include files that match a particular
1775 pattern, such as *.conf, for example.</p>
1777 <p>When a wildcard is specified for a <strong>file</strong> component of
1778 the path, and no file matches the wildcard, the
1779 <code class="directive"><a href="#include">Include</a></code>
1780 directive will be <strong>silently ignored</strong>. When a wildcard is
1781 specified for a <strong>directory</strong> component of the path, and
1782 no directory matches the wildcard, the
1783 <code class="directive"><a href="#include">Include</a></code> directive will
1784 <strong>fail with an error</strong> saying the directory cannot be found.
1787 <p>For further control over the behaviour of the server when no files or
1788 directories match, prefix the path with the modifiers <var>optional</var>
1789 or <var>strict</var>. If <var>optional</var> is specified, any wildcard
1790 file or directory that does not match will be silently ignored. If
1791 <var>strict</var> is specified, any wildcard file or directory that does
1792 not match at least one file will cause server startup to fail.</p>
1794 <p>When a directory or file component of the path is
1795 specified exactly, and that directory or file does not exist,
1796 <code class="directive"><a href="#include">Include</a></code> directive will fail with an
1797 error saying the file or directory cannot be found.</p>
1799 <p>The file path specified may be an absolute path, or may be relative
1800 to the <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory.</p>
1804 <div class="example"><p><code>
1805 Include /usr/local/apache2/conf/ssl.conf<br />
1806 Include /usr/local/apache2/conf/vhosts/*.conf
1809 <p>Or, providing paths relative to your <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory:</p>
1811 <div class="example"><p><code>
1812 Include conf/ssl.conf<br />
1813 Include conf/vhosts/*.conf
1816 <p>Wildcards may be included in the directory or file portion of the
1817 path. In the following example, the server will fail to load if no
1818 directories match conf/vhosts/*, but will load successfully if no
1819 files match *.conf.</p>
1821 <div class="example"><p><code>
1822 Include conf/vhosts/*/vhost.conf<br />
1823 Include conf/vhosts/*/*.conf
1826 <p>In this example, the server will fail to load if either
1827 conf/vhosts/* matches no directories, or if *.conf matches no files:</p>
1829 <div class="example"><p><code>
1830 Include strict conf/vhosts/*/*.conf
1833 <p>In this example, the server load successfully if either conf/vhosts/*
1834 matches no directories, or if *.conf matches no files:</p>
1836 <div class="example"><p><code>
1837 Include optional conf/vhosts/*/*.conf
1843 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
1846 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1847 <div class="directive-section"><h2><a name="KeepAlive" id="KeepAlive">KeepAlive</a> <a name="keepalive" id="keepalive">Directive</a></h2>
1848 <table class="directive">
1849 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables HTTP persistent connections</td></tr>
1850 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAlive On|Off</code></td></tr>
1851 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAlive On</code></td></tr>
1852 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1853 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1854 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1856 <p>The Keep-Alive extension to HTTP/1.0 and the persistent
1857 connection feature of HTTP/1.1 provide long-lived HTTP sessions
1858 which allow multiple requests to be sent over the same TCP
1859 connection. In some cases this has been shown to result in an
1860 almost 50% speedup in latency times for HTML documents with
1861 many images. To enable Keep-Alive connections, set
1862 <code>KeepAlive On</code>.</p>
1864 <p>For HTTP/1.0 clients, Keep-Alive connections will only be
1865 used if they are specifically requested by a client. In
1866 addition, a Keep-Alive connection with an HTTP/1.0 client can
1867 only be used when the length of the content is known in
1868 advance. This implies that dynamic content such as CGI output,
1869 SSI pages, and server-generated directory listings will
1870 generally not use Keep-Alive connections to HTTP/1.0 clients.
1871 For HTTP/1.1 clients, persistent connections are the default
1872 unless otherwise specified. If the client requests it, chunked
1873 encoding will be used in order to send content of unknown
1874 length over persistent connections.</p>
1876 <p>When a client uses a Keep-Alive connection it will be counted
1877 as a single "request" for the <code class="directive"><a href="../mod/mpm_common.html#maxconnectionsperchild">MaxConnectionsPerChild</a></code> directive, regardless
1878 of how many requests are sent using the connection.</p>
1882 <li><code class="directive"><a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></code></li>
1885 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1886 <div class="directive-section"><h2><a name="KeepAliveTimeout" id="KeepAliveTimeout">KeepAliveTimeout</a> <a name="keepalivetimeout" id="keepalivetimeout">Directive</a></h2>
1887 <table class="directive">
1888 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for subsequent
1889 requests on a persistent connection</td></tr>
1890 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAliveTimeout <var>num</var>[ms]</code></td></tr>
1891 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAliveTimeout 5</code></td></tr>
1892 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1893 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1894 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1895 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Specifying a value in milliseconds is available in
1896 Apache httpd 2.3.2 and later</td></tr>
1898 <p>The number of seconds Apache httpd will wait for a subsequent
1899 request before closing the connection. By adding a postfix of ms the
1900 timeout can be also set in milliseconds. Once a request has been
1901 received, the timeout value specified by the
1902 <code class="directive"><a href="#timeout">Timeout</a></code> directive applies.</p>
1904 <p>Setting <code class="directive">KeepAliveTimeout</code> to a high value
1905 may cause performance problems in heavily loaded servers. The
1906 higher the timeout, the more server processes will be kept
1907 occupied waiting on connections with idle clients.</p>
1909 <p>In a name-based virtual host context, the value of the first
1910 defined virtual host (the default host) in a set of <code class="directive"><a href="#namevirtualhost">NameVirtualHost</a></code> will be used.
1911 The other values will be ignored.</p>
1914 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1915 <div class="directive-section"><h2><a name="Limit" id="Limit"><Limit></a> <a name="limit" id="limit">Directive</a></h2>
1916 <table class="directive">
1917 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict enclosed access controls to only certain HTTP
1919 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Limit <var>method</var> [<var>method</var>] ... > ...
1920 </Limit></code></td></tr>
1921 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
1922 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
1923 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1924 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1926 <p>Access controls are normally effective for
1927 <strong>all</strong> access methods, and this is the usual
1928 desired behavior. <strong>In the general case, access control
1929 directives should not be placed within a
1930 <code class="directive"><Limit></code> section.</strong></p>
1932 <p>The purpose of the <code class="directive"><Limit></code>
1933 directive is to restrict the effect of the access controls to the
1934 nominated HTTP methods. For all other methods, the access
1935 restrictions that are enclosed in the <code class="directive"><Limit></code> bracket <strong>will have no
1936 effect</strong>. The following example applies the access control
1937 only to the methods <code>POST</code>, <code>PUT</code>, and
1938 <code>DELETE</code>, leaving all other methods unprotected:</p>
1940 <div class="example"><p><code>
1941 <Limit POST PUT DELETE><br />
1942 <span class="indent">
1943 Require valid-user<br />
1948 <p>The method names listed can be one or more of: <code>GET</code>,
1949 <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
1950 <code>CONNECT</code>, <code>OPTIONS</code>,
1951 <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
1952 <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
1953 <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
1954 case-sensitive.</strong> If <code>GET</code> is used it will also
1955 restrict <code>HEAD</code> requests. The <code>TRACE</code> method
1956 cannot be limited (see <code class="directive"><a href="#traceenable">TraceEnable</a></code>).</p>
1958 <div class="warning">A <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section should always be
1959 used in preference to a <code class="directive"><Limit></code>
1960 section when restricting access, since a <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section provides protection
1961 against arbitrary methods.</div>
1963 <p>The <code class="directive"><Limit></code> and
1964 <code class="directive"><a href="#limitexcept"><LimitExcept></a></code>
1965 directives may be nested. In this case, each successive level of
1966 <code class="directive"><Limit></code> or <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> directives must
1967 further restrict the set of methods to which access controls apply.</p>
1969 <div class="warning">When using
1970 <code class="directive"><Limit></code> or
1971 <code class="directive"><LimitExcept></code> directives with
1972 the <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directive,
1973 note that the first <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code>
1974 to succeed authorizes the request, regardless of the presence of other
1975 <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directives.</div>
1977 <p>For example, given the following configuration, all users will
1978 be authorized for <code>POST</code> requests, and the
1979 <code>Require group editors</code> directive will be ignored
1982 <div class="example"><p><code>
1983 <LimitExcept GET>
1984 <span class="indent">
1987 </LimitExcept><br />
1989 <span class="indent">
1990 Require group editors
1996 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1997 <div class="directive-section"><h2><a name="LimitExcept" id="LimitExcept"><LimitExcept></a> <a name="limitexcept" id="limitexcept">Directive</a></h2>
1998 <table class="directive">
1999 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict access controls to all HTTP methods
2000 except the named ones</td></tr>
2001 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LimitExcept <var>method</var> [<var>method</var>] ... > ...
2002 </LimitExcept></code></td></tr>
2003 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2004 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2005 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2006 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2008 <p><code class="directive"><LimitExcept></code> and
2009 <code></LimitExcept></code> are used to enclose
2010 a group of access control directives which will then apply to any
2011 HTTP access method <strong>not</strong> listed in the arguments;
2012 i.e., it is the opposite of a <code class="directive"><a href="#limit"><Limit></a></code> section and can be used to control
2013 both standard and nonstandard/unrecognized methods. See the
2014 documentation for <code class="directive"><a href="#limit"><Limit></a></code> for more details.</p>
2018 <div class="example"><p><code>
2019 <LimitExcept POST GET><br />
2020 <span class="indent">
2021 Require valid-user<br />
2023 </LimitExcept>
2028 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2029 <div class="directive-section"><h2><a name="LimitInternalRecursion" id="LimitInternalRecursion">LimitInternalRecursion</a> <a name="limitinternalrecursion" id="limitinternalrecursion">Directive</a></h2>
2030 <table class="directive">
2031 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine maximum number of internal redirects and nested
2032 subrequests</td></tr>
2033 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitInternalRecursion <var>number</var> [<var>number</var>]</code></td></tr>
2034 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitInternalRecursion 10</code></td></tr>
2035 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2036 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2037 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2038 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.0.47 and later</td></tr>
2040 <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
2041 redirects the original request to a CGI script. A subrequest is Apache httpd's
2042 mechanism to find out what would happen for some URI if it were requested.
2043 For example, <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> uses subrequests to look for the
2044 files listed in the <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
2047 <p><code class="directive">LimitInternalRecursion</code> prevents the server
2048 from crashing when entering an infinite loop of internal redirects or
2049 subrequests. Such loops are usually caused by misconfigurations.</p>
2051 <p>The directive stores two different limits, which are evaluated on
2052 per-request basis. The first <var>number</var> is the maximum number of
2053 internal redirects, that may follow each other. The second <var>number</var>
2054 determines, how deep subrequests may be nested. If you specify only one
2055 <var>number</var>, it will be assigned to both limits.</p>
2057 <div class="example"><h3>Example</h3><p><code>
2058 LimitInternalRecursion 5
2062 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2063 <div class="directive-section"><h2><a name="LimitRequestBody" id="LimitRequestBody">LimitRequestBody</a> <a name="limitrequestbody" id="limitrequestbody">Directive</a></h2>
2064 <table class="directive">
2065 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restricts the total size of the HTTP request body sent
2066 from the client</td></tr>
2067 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestBody <var>bytes</var></code></td></tr>
2068 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestBody 0</code></td></tr>
2069 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2070 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2071 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2072 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2074 <p>This directive specifies the number of <var>bytes</var> from 0
2075 (meaning unlimited) to 2147483647 (2GB) that are allowed in a
2076 request body. See the note below for the limited applicability
2077 to proxy requests.</p>
2079 <p>The <code class="directive">LimitRequestBody</code> directive allows
2080 the user to set a limit on the allowed size of an HTTP request
2081 message body within the context in which the directive is given
2082 (server, per-directory, per-file or per-location). If the client
2083 request exceeds that limit, the server will return an error
2084 response instead of servicing the request. The size of a normal
2085 request message body will vary greatly depending on the nature of
2086 the resource and the methods allowed on that resource. CGI scripts
2087 typically use the message body for retrieving form information.
2088 Implementations of the <code>PUT</code> method will require
2089 a value at least as large as any representation that the server
2090 wishes to accept for that resource.</p>
2092 <p>This directive gives the server administrator greater
2093 control over abnormal client request behavior, which may be
2094 useful for avoiding some forms of denial-of-service
2097 <p>If, for example, you are permitting file upload to a particular
2098 location, and wish to limit the size of the uploaded file to 100K,
2099 you might use the following directive:</p>
2101 <div class="example"><p><code>
2102 LimitRequestBody 102400
2105 <div class="note"><p>For a full description of how this directive is interpreted by
2106 proxy requests, see the <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> documentation.</p>
2111 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2112 <div class="directive-section"><h2><a name="LimitRequestFields" id="LimitRequestFields">LimitRequestFields</a> <a name="limitrequestfields" id="limitrequestfields">Directive</a></h2>
2113 <table class="directive">
2114 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of HTTP request header fields that
2115 will be accepted from the client</td></tr>
2116 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFields <var>number</var></code></td></tr>
2117 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFields 100</code></td></tr>
2118 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2119 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2120 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2122 <p><var>Number</var> is an integer from 0 (meaning unlimited) to
2123 32767. The default value is defined by the compile-time
2124 constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
2127 <p>The <code class="directive">LimitRequestFields</code> directive allows
2128 the server administrator to modify the limit on the number of
2129 request header fields allowed in an HTTP request. A server needs
2130 this value to be larger than the number of fields that a normal
2131 client request might include. The number of request header fields
2132 used by a client rarely exceeds 20, but this may vary among
2133 different client implementations, often depending upon the extent
2134 to which a user has configured their browser to support detailed
2135 content negotiation. Optional HTTP extensions are often expressed
2136 using request header fields.</p>
2138 <p>This directive gives the server administrator greater
2139 control over abnormal client request behavior, which may be
2140 useful for avoiding some forms of denial-of-service attacks.
2141 The value should be increased if normal clients see an error
2142 response from the server that indicates too many fields were
2143 sent in the request.</p>
2147 <div class="example"><p><code>
2148 LimitRequestFields 50
2151 <div class="warning"><h3>Warning</h3>
2152 <p> When name-based virtual hosting is used, the value for this
2153 directive is taken from the default (first-listed) virtual host for the
2154 <code class="directive">NameVirtualHost</code> the connection was mapped to.</p>
2159 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2160 <div class="directive-section"><h2><a name="LimitRequestFieldSize" id="LimitRequestFieldSize">LimitRequestFieldSize</a> <a name="limitrequestfieldsize" id="limitrequestfieldsize">Directive</a></h2>
2161 <table class="directive">
2162 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of the HTTP request header allowed from the
2164 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFieldSize <var>bytes</var></code></td></tr>
2165 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFieldSize 8190</code></td></tr>
2166 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2167 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2168 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2170 <p>This directive specifies the number of <var>bytes</var>
2171 that will be allowed in an HTTP request header.</p>
2173 <p>The <code class="directive">LimitRequestFieldSize</code> directive
2174 allows the server administrator to reduce or increase the limit
2175 on the allowed size of an HTTP request header field. A server
2176 needs this value to be large enough to hold any one header field
2177 from a normal client request. The size of a normal request header
2178 field will vary greatly among different client implementations,
2179 often depending upon the extent to which a user has configured
2180 their browser to support detailed content negotiation. SPNEGO
2181 authentication headers can be up to 12392 bytes.</p>
2183 <p>This directive gives the server administrator greater
2184 control over abnormal client request behavior, which may be
2185 useful for avoiding some forms of denial-of-service attacks.</p>
2189 <div class="example"><p><code>
2190 LimitRequestFieldSize 4094
2193 <div class="note">Under normal conditions, the value should not be changed from
2196 <div class="warning"><h3>Warning</h3>
2197 <p> When name-based virtual hosting is used, the value for this
2198 directive is taken from the default (first-listed) virtual host for the
2199 <code class="directive">NameVirtualHost</code> the connection was mapped to.</p>
2204 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2205 <div class="directive-section"><h2><a name="LimitRequestLine" id="LimitRequestLine">LimitRequestLine</a> <a name="limitrequestline" id="limitrequestline">Directive</a></h2>
2206 <table class="directive">
2207 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limit the size of the HTTP request line that will be accepted
2208 from the client</td></tr>
2209 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestLine <var>bytes</var></code></td></tr>
2210 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestLine 8190</code></td></tr>
2211 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2212 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2213 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2215 <p>This directive sets the number of <var>bytes</var> that will be
2216 allowed on the HTTP request-line.</p>
2218 <p>The <code class="directive">LimitRequestLine</code> directive allows
2219 the server administrator to reduce or increase the limit on the allowed size
2220 of a client's HTTP request-line. Since the request-line consists of the
2221 HTTP method, URI, and protocol version, the
2222 <code class="directive">LimitRequestLine</code> directive places a
2223 restriction on the length of a request-URI allowed for a request
2224 on the server. A server needs this value to be large enough to
2225 hold any of its resource names, including any information that
2226 might be passed in the query part of a <code>GET</code> request.</p>
2228 <p>This directive gives the server administrator greater
2229 control over abnormal client request behavior, which may be
2230 useful for avoiding some forms of denial-of-service attacks.</p>
2234 <div class="example"><p><code>
2235 LimitRequestLine 4094
2238 <div class="note">Under normal conditions, the value should not be changed from
2241 <div class="warning"><h3>Warning</h3>
2242 <p> When name-based virtual hosting is used, the value for this
2243 directive is taken from the default (first-listed) virtual host for the
2244 <code class="directive">NameVirtualHost</code> the connection was mapped to.</p>
2249 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2250 <div class="directive-section"><h2><a name="LimitXMLRequestBody" id="LimitXMLRequestBody">LimitXMLRequestBody</a> <a name="limitxmlrequestbody" id="limitxmlrequestbody">Directive</a></h2>
2251 <table class="directive">
2252 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of an XML-based request body</td></tr>
2253 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitXMLRequestBody <var>bytes</var></code></td></tr>
2254 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitXMLRequestBody 1000000</code></td></tr>
2255 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2256 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2257 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2258 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2260 <p>Limit (in bytes) on maximum size of an XML-based request
2261 body. A value of <code>0</code> will disable any checking.</p>
2265 <div class="example"><p><code>
2266 LimitXMLRequestBody 0
2271 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2272 <div class="directive-section"><h2><a name="Location" id="Location"><Location></a> <a name="location" id="location">Directive</a></h2>
2273 <table class="directive">
2274 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to matching
2276 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Location
2277 <var>URL-path</var>|<var>URL</var>> ... </Location></code></td></tr>
2278 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2279 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2280 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2282 <p>The <code class="directive"><Location></code> directive
2283 limits the scope of the enclosed directives by URL. It is similar to the
2284 <code class="directive"><a href="#directory"><Directory></a></code>
2285 directive, and starts a subsection which is terminated with a
2286 <code></Location></code> directive. <code class="directive"><Location></code> sections are processed in the
2287 order they appear in the configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
2288 <code>.htaccess</code> files are read, and after the <code class="directive"><a href="#files"><Files></a></code> sections.</p>
2290 <p><code class="directive"><Location></code> sections operate
2291 completely outside the filesystem. This has several consequences.
2292 Most importantly, <code class="directive"><Location></code>
2293 directives should not be used to control access to filesystem
2294 locations. Since several different URLs may map to the same
2295 filesystem location, such access controls may by circumvented.</p>
2297 <p>The enclosed directives will be applied to the request if the path component
2298 of the URL meets <em>any</em> of the following criteria:
2301 <li>The specified location matches exactly the path component of the URL.
2303 <li>The specified location, which ends in a forward slash, is a prefix
2304 of the path component of the URL (treated as a context root).
2306 <li>The specified location, with the addition of a trailing slash, is a
2307 prefix of the path component of the URL (also treated as a context root).
2311 In the example below, where no trailing slash is used, requests to
2312 /private1, /private1/ and /private1/file.txt will have the enclosed
2313 directives applied, but /private1other would not.
2315 <div class="example"><p><code>
2316 <Location /private1>
2320 In the example below, where a trailing slash is used, requests to
2321 /private2/ and /private2/file.txt will have the enclosed
2322 directives applied, but /private2 and /private2other would not.
2324 <div class="example"><p><code>
2325 <Location /private2<em>/</em>>
2329 <div class="note"><h3>When to use <code class="directive"><Location></code></h3>
2331 <p>Use <code class="directive"><Location></code> to apply
2332 directives to content that lives outside the filesystem. For
2333 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
2334 <code><Location /></code>, which is an easy way to
2335 apply a configuration to the entire server.</p>
2338 <p>For all origin (non-proxy) requests, the URL to be matched is a
2339 URL-path of the form <code>/path/</code>. <em>No scheme, hostname,
2340 port, or query string may be included.</em> For proxy requests, the
2341 URL to be matched is of the form
2342 <code>scheme://servername/path</code>, and you must include the
2345 <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
2346 any single character, and <code>*</code> matches any sequences of
2347 characters. Neither wildcard character matches a / in the URL-path.</p>
2349 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
2350 can also be used, with the addition of the <code>~</code>
2351 character. For example:</p>
2353 <div class="example"><p><code>
2354 <Location ~ "/(extra|special)/data">
2357 <p>would match URLs that contained the substring <code>/extra/data</code>
2358 or <code>/special/data</code>. The directive <code class="directive"><a href="#locationmatch"><LocationMatch></a></code> behaves
2359 identical to the regex version of <code class="directive"><Location></code>, and is preferred, for the
2360 simple reason that <code>~</code> is hard to distinguish from
2361 <code>-</code> in many fonts.</p>
2363 <p>The <code class="directive"><Location></code>
2364 functionality is especially useful when combined with the
2365 <code class="directive"><a href="#sethandler">SetHandler</a></code>
2366 directive. For example, to enable status requests, but allow them
2367 only from browsers at <code>example.com</code>, you might use:</p>
2369 <div class="example"><p><code>
2370 <Location /status><br />
2371 <span class="indent">
2372 SetHandler server-status<br />
2373 Require host example.com<br />
2378 <div class="note"><h3>Note about / (slash)</h3>
2379 <p>The slash character has special meaning depending on where in a
2380 URL it appears. People may be used to its behavior in the filesystem
2381 where multiple adjacent slashes are frequently collapsed to a single
2382 slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
2383 <code>/home/foo</code>). In URL-space this is not necessarily true.
2384 The <code class="directive"><a href="#locationmatch"><LocationMatch></a></code>
2385 directive and the regex version of <code class="directive"><Location></code> require you to explicitly specify multiple
2386 slashes if that is your intention.</p>
2388 <p>For example, <code><LocationMatch ^/abc></code> would match
2389 the request URL <code>/abc</code> but not the request URL <code>
2390 //abc</code>. The (non-regex) <code class="directive"><Location></code> directive behaves similarly when used for
2391 proxy requests. But when (non-regex) <code class="directive"><Location></code> is used for non-proxy requests it will
2392 implicitly match multiple slashes with a single slash. For example,
2393 if you specify <code><Location /abc/def></code> and the
2394 request is to <code>/abc//def</code> then it will match.</p>
2399 <li><a href="../sections.html">How <Directory>, <Location>
2400 and <Files> sections work</a> for an explanation of how these
2401 different sections are combined when a request is received.</li>
2402 <li><code class="directive"><a href="#locationmatch">LocationMatch</a></code></li>
2405 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2406 <div class="directive-section"><h2><a name="LocationMatch" id="LocationMatch"><LocationMatch></a> <a name="locationmatch" id="locationmatch">Directive</a></h2>
2407 <table class="directive">
2408 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to regular-expression
2409 matching URLs</td></tr>
2410 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LocationMatch
2411 <var>regex</var>> ... </LocationMatch></code></td></tr>
2412 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2413 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2414 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2416 <p>The <code class="directive"><LocationMatch></code> directive
2417 limits the scope of the enclosed directives by URL, in an identical manner
2418 to <code class="directive"><a href="#location"><Location></a></code>. However,
2419 it takes a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
2420 as an argument instead of a simple string. For example:</p>
2422 <div class="example"><p><code>
2423 <LocationMatch "/(extra|special)/data">
2426 <p>would match URLs that contained the substring <code>/extra/data</code>
2427 or <code>/special/data</code>.</p>
2431 <li><a href="../sections.html">How <Directory>, <Location>
2432 and <Files> sections work</a> for an explanation of how these
2433 different sections are combined when a request is received</li>
2436 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2437 <div class="directive-section"><h2><a name="LogLevel" id="LogLevel">LogLevel</a> <a name="loglevel" id="loglevel">Directive</a></h2>
2438 <table class="directive">
2439 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Controls the verbosity of the ErrorLog</td></tr>
2440 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel [<var>module</var>:]<var>level</var>
2441 [<var>module</var>:<var>level</var>] ...
2443 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LogLevel warn</code></td></tr>
2444 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2445 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2446 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2447 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Per-module and per-directory configuration is available in
2448 Apache HTTP Server 2.3.6 and later</td></tr>
2450 <p><code class="directive">LogLevel</code> adjusts the verbosity of the
2451 messages recorded in the error logs (see <code class="directive"><a href="#errorlog">ErrorLog</a></code> directive). The following
2452 <var>level</var>s are available, in order of decreasing
2455 <table class="bordered">
2458 <th><strong>Level</strong> </th>
2460 <th><strong>Description</strong> </th>
2462 <th><strong>Example</strong> </th>
2466 <td><code>emerg</code> </td>
2468 <td>Emergencies - system is unusable.</td>
2470 <td>"Child cannot open lock file. Exiting"</td>
2474 <td><code>alert</code> </td>
2476 <td>Action must be taken immediately.</td>
2478 <td>"getpwuid: couldn't determine user name from uid"</td>
2482 <td><code>crit</code> </td>
2484 <td>Critical Conditions.</td>
2486 <td>"socket: Failed to get a socket, exiting child"</td>
2490 <td><code>error</code> </td>
2492 <td>Error conditions.</td>
2494 <td>"Premature end of script headers"</td>
2498 <td><code>warn</code> </td>
2500 <td>Warning conditions.</td>
2502 <td>"child process 1234 did not exit, sending another
2507 <td><code>notice</code> </td>
2509 <td>Normal but significant condition.</td>
2511 <td>"httpd: caught SIGBUS, attempting to dump core in
2516 <td><code>info</code> </td>
2518 <td>Informational.</td>
2520 <td>"Server seems busy, (you may need to increase
2521 StartServers, or Min/MaxSpareServers)..."</td>
2525 <td><code>debug</code> </td>
2527 <td>Debug-level messages</td>
2529 <td>"Opening config file ..."</td>
2532 <td><code>trace1</code> </td>
2534 <td>Trace messages</td>
2536 <td>"proxy: FTP: control connection complete"</td>
2539 <td><code>trace2</code> </td>
2541 <td>Trace messages</td>
2543 <td>"proxy: CONNECT: sending the CONNECT request to the remote proxy"</td>
2546 <td><code>trace3</code> </td>
2548 <td>Trace messages</td>
2550 <td>"openssl: Handshake: start"</td>
2553 <td><code>trace4</code> </td>
2555 <td>Trace messages</td>
2557 <td>"read from buffered SSL brigade, mode 0, 17 bytes"</td>
2560 <td><code>trace5</code> </td>
2562 <td>Trace messages</td>
2564 <td>"map lookup FAILED: map=rewritemap key=keyname"</td>
2567 <td><code>trace6</code> </td>
2569 <td>Trace messages</td>
2571 <td>"cache lookup FAILED, forcing new map lookup"</td>
2574 <td><code>trace7</code> </td>
2576 <td>Trace messages, dumping large amounts of data</td>
2578 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2581 <td><code>trace8</code> </td>
2583 <td>Trace messages, dumping large amounts of data</td>
2585 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2589 <p>When a particular level is specified, messages from all
2590 other levels of higher significance will be reported as well.
2591 <em>E.g.</em>, when <code>LogLevel info</code> is specified,
2592 then messages with log levels of <code>notice</code> and
2593 <code>warn</code> will also be posted.</p>
2595 <p>Using a level of at least <code>crit</code> is
2600 <div class="example"><p><code>
2604 <div class="note"><h3>Note</h3>
2605 <p>When logging to a regular file messages of the level
2606 <code>notice</code> cannot be suppressed and thus are always
2607 logged. However, this doesn't apply when logging is done
2608 using <code>syslog</code>.</p>
2611 <p>Specifying a level without a module name will reset the level
2612 for all modules to that level. Specifying a level with a module
2613 name will set the level for that module only. It is possible to
2614 use the module source file name, the module identifier, or the
2615 module identifier with the trailing <code>_module</code> omitted
2616 as module specification. This means the following three specifications
2619 <div class="example"><p><code>
2620 LogLevel info ssl:warn<br />
2621 LogLevel info mod_ssl.c:warn<br />
2622 LogLevel info ssl_module:warn<br />
2625 <p>It is also possible to change the level per directory:</p>
2627 <div class="example"><p><code>
2629 <Directory /usr/local/apache/htdocs/app><br />
2630 LogLevel debug<br />
2635 Per directory loglevel configuration only affects messages that are
2636 logged after the request has been parsed and that are associated with
2637 the request. Log messages which are associated with the connection or
2638 the server are not affected.
2642 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2643 <div class="directive-section"><h2><a name="MaxKeepAliveRequests" id="MaxKeepAliveRequests">MaxKeepAliveRequests</a> <a name="maxkeepaliverequests" id="maxkeepaliverequests">Directive</a></h2>
2644 <table class="directive">
2645 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of requests allowed on a persistent
2646 connection</td></tr>
2647 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxKeepAliveRequests <var>number</var></code></td></tr>
2648 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxKeepAliveRequests 100</code></td></tr>
2649 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2650 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2651 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2653 <p>The <code class="directive">MaxKeepAliveRequests</code> directive
2654 limits the number of requests allowed per connection when
2655 <code class="directive"><a href="#keepalive">KeepAlive</a></code> is on. If it is
2656 set to <code>0</code>, unlimited requests will be allowed. We
2657 recommend that this setting be kept to a high value for maximum
2658 server performance.</p>
2662 <div class="example"><p><code>
2663 MaxKeepAliveRequests 500
2667 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2668 <div class="directive-section"><h2><a name="Mutex" id="Mutex">Mutex</a> <a name="mutex" id="mutex">Directive</a></h2>
2669 <table class="directive">
2670 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures mutex mechanism and lock file directory for all
2671 or specified mutexes</td></tr>
2672 <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>
2673 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Mutex default</code></td></tr>
2674 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
2675 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2676 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2677 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.4 and later</td></tr>
2679 <p>The <code class="directive">Mutex</code> directive sets the mechanism,
2680 and optionally the lock file location, that httpd and modules use
2681 to serialize access to resources. Specify <code>default</code> as
2682 the first argument to change the settings for all mutexes; specify
2683 a mutex name (see table below) as the first argument to override
2684 defaults only for that mutex.</p>
2686 <p>The <code class="directive">Mutex</code> directive is typically used in
2687 the following exceptional situations:</p>
2690 <li>change the mutex mechanism when the default mechanism selected
2691 by <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> has a functional or performance
2694 <li>change the directory used by file-based mutexes when the
2695 default directory does not support locking</li>
2698 <div class="note"><h3>Supported modules</h3>
2699 <p>This directive only configures mutexes which have been registered
2700 with the core server using the <code>ap_mutex_register()</code> API.
2701 All modules bundled with httpd support the <code class="directive">Mutex</code>
2702 directive, but third-party modules may not. Consult the documentation
2703 of the third-party module, which must indicate the mutex name(s) which
2704 can be configured if this directive is supported.</p>
2707 <p>The following mutex <em>mechanisms</em> are available:</p>
2709 <li><code>default | yes</code>
2710 <p>This selects the default locking implementation, as determined by
2711 <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a>. The default locking implementation can
2712 be displayed by running <code class="program"><a href="../programs/httpd.html">httpd</a></code> with the
2713 <code>-V</code> option.</p></li>
2715 <li><code>none | no</code>
2716 <p>This effectively disables the mutex, and is only allowed for a
2717 mutex if the module indicates that it is a valid choice. Consult the
2718 module documentation for more information.</p></li>
2720 <li><code>posixsem</code>
2721 <p>This is a mutex variant based on a Posix semaphore.</p>
2723 <div class="warning"><h3>Warning</h3>
2724 <p>The semaphore ownership is not recovered if a thread in the process
2725 holding the mutex segfaults, resulting in a hang of the web server.</p>
2729 <li><code>sysvsem</code>
2730 <p>This is a mutex variant based on a SystemV IPC semaphore.</p>
2732 <div class="warning"><h3>Warning</h3>
2733 <p>It is possible to "leak" SysV semaphores if processes crash
2734 before the semaphore is removed.</p>
2737 <div class="warning"><h3>Security</h3>
2738 <p>The semaphore API allows for a denial of service attack by any
2739 CGIs running under the same uid as the webserver (<em>i.e.</em>,
2740 all CGIs, unless you use something like <code class="program"><a href="../programs/suexec.html">suexec</a></code>
2741 or <code>cgiwrapper</code>).</p>
2745 <li><code>sem</code>
2746 <p>This selects the "best" available semaphore implementation, choosing
2747 between Posix and SystemV IPC semaphores, in that order.</p></li>
2749 <li><code>pthread</code>
2750 <p>This is a mutex variant based on cross-process Posix thread
2753 <div class="warning"><h3>Warning</h3>
2754 <p>On most systems, if a child process terminates abnormally while
2755 holding a mutex that uses this implementation, the server will deadlock
2756 and stop responding to requests. When this occurs, the server will
2757 require a manual restart to recover.</p>
2758 <p>Solaris is a notable exception as it provides a mechanism which
2759 usually allows the mutex to be recovered after a child process
2760 terminates abnormally while holding a mutex.</p>
2761 <p>If your system implements the
2762 <code>pthread_mutexattr_setrobust_np()</code> function, you may be able
2763 to use the <code>pthread</code> option safely.</p>
2767 <li><code>fcntl:/path/to/mutex</code>
2768 <p>This is a mutex variant where a physical (lock-)file and the
2769 <code>fcntl()</code> function are used as the mutex.</p>
2771 <div class="warning"><h3>Warning</h3>
2772 <p>When multiple mutexes based on this mechanism are used within
2773 multi-threaded, multi-process environments, deadlock errors (EDEADLK)
2774 can be reported for valid mutex operations if <code>fcntl()</code>
2775 is not thread-aware, such as on Solaris.</p>
2779 <li><code>flock:/path/to/mutex</code>
2780 <p>This is similar to the <code>fcntl:/path/to/mutex</code> method
2781 with the exception that the <code>flock()</code> function is used to
2782 provide file locking.</p></li>
2784 <li><code>file:/path/to/mutex</code>
2785 <p>This selects the "best" available file locking implementation,
2786 choosing between <code>fcntl</code> and <code>flock</code>, in that
2790 <p>Most mechanisms are only available on selected platforms, where the
2791 underlying platform and <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> support it. Mechanisms
2792 which aren't available on all platforms are <em>posixsem</em>,
2793 <em>sysvsem</em>, <em>sem</em>, <em>pthread</em>, <em>fcntl</em>,
2794 <em>flock</em>, and <em>file</em>.</p>
2796 <p>With the file-based mechanisms <em>fcntl</em> and <em>flock</em>,
2797 the path, if provided, is a directory where the lock file will be created.
2798 The default directory is httpd's run-time file directory relative to
2799 <code class="directive"><a href="#serverroot">ServerRoot</a></code>. Always use a local disk
2800 filesystem for <code>/path/to/mutex</code> and never a directory residing
2801 on a NFS- or AFS-filesystem. The basename of the file will be the mutex
2802 type, an optional instance string provided by the module, and unless the
2803 <code>OmitPID</code> keyword is specified, the process id of the httpd
2804 parent process will be appended to to make the file name unique, avoiding
2805 conflicts when multiple httpd instances share a lock file directory. For
2806 example, if the mutex name is <code>mpm-accept</code> and the lock file
2807 directory is <code>/var/httpd/locks</code>, the lock file name for the
2808 httpd instance with parent process id 12345 would be
2809 <code>/var/httpd/locks/mpm-accept.12345</code>.</p>
2811 <div class="warning"><h3>Security</h3>
2812 <p>It is best to <em>avoid</em> putting mutex files in a world-writable
2813 directory such as <code>/var/tmp</code> because someone could create
2814 a denial of service attack and prevent the server from starting by
2815 creating a lockfile with the same name as the one the server will try
2819 <p>The following table documents the names of mutexes used by httpd
2820 and bundled modules.</p>
2822 <table class="bordered"><tr class="header">
2825 <th>Protected resource</th>
2828 <td><code>mpm-accept</code></td>
2829 <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>
2830 <td>incoming connections, to avoid the thundering herd problem;
2831 for more information, refer to the
2832 <a href="../misc/perf-tuning.html">performance tuning</a>
2836 <td><code>authdigest-client</code></td>
2837 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
2838 <td>client list in shared memory</td>
2841 <td><code>authdigest-opaque</code></td>
2842 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
2843 <td>counter in shared memory</td>
2846 <td><code>ldap-cache</code></td>
2847 <td><code class="module"><a href="../mod/mod_ldap.html">mod_ldap</a></code></td>
2848 <td>LDAP result cache</td>
2851 <td><code>rewrite-map</code></td>
2852 <td><code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code></td>
2853 <td>communication with external mapping programs, to avoid
2854 intermixed I/O from multiple requests</td>
2857 <td><code>ssl-cache</code></td>
2858 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
2859 <td>SSL session cache</td>
2862 <td><code>ssl-stapling</code></td>
2863 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
2864 <td>OCSP stapling response cache</td>
2867 <td><code>watchdog-callback</code></td>
2868 <td><code class="module"><a href="../mod/mod_watchdog.html">mod_watchdog</a></code></td>
2869 <td>callback function of a particular client module</td>
2873 <p>The <code>OmitPID</code> keyword suppresses the addition of the httpd
2874 parent process id from the lock file name.</p>
2876 <p>In the following example, the mutex mechanism for the MPM accept
2877 mutex will be changed from the compiled-in default to <code>fcntl</code>,
2878 with the associated lock file created in directory
2879 <code>/var/httpd/locks</code>. The mutex mechanism for all other mutexes
2880 will be changed from the compiled-in default to <code>sysvsem</code>.</p>
2882 <div class="example"><p><code>
2883 Mutex default sysvsem<br />
2884 Mutex mpm-accept fcntl:/var/httpd/locks
2888 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2889 <div class="directive-section"><h2><a name="NameVirtualHost" id="NameVirtualHost">NameVirtualHost</a> <a name="namevirtualhost" id="namevirtualhost">Directive</a></h2>
2890 <table class="directive">
2891 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Designates an IP address for name-virtual
2893 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NameVirtualHost <var>addr</var>[:<var>port</var>]</code></td></tr>
2894 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
2895 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2896 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2899 <p>A single <code class="directive">NameVirtualHost</code> directive
2900 identifies a set of identical virtual hosts on which the server will
2901 further select from on the basis of the <em>hostname</em>
2902 requested by the client. The <code class="directive">NameVirtualHost</code>
2903 directive is a required directive if you want to configure
2904 <a href="../vhosts/">name-based virtual hosts</a>.</p>
2906 <p>This directive, and the corresponding <code class="directive">VirtualHost</code>,
2907 <em>must</em> be qualified with a port number if the server supports both HTTP
2908 and HTTPS connections.</p>
2910 <p>Although <var>addr</var> can be a hostname, it is recommended
2911 that you always use an IP address or a wildcard. A wildcard
2912 NameVirtualHost matches only virtualhosts that also have a literal wildcard
2913 as their argument.</p>
2915 <p>In cases where a firewall or other proxy receives the requests and
2916 forwards them on a different IP address to the server, you must specify the
2917 IP address of the physical interface on the machine which will be
2918 servicing the requests. </p>
2920 <p> In the example below, requests received on interface 192.0.2.1 and port 80
2921 will only select among the first two virtual hosts. Requests received on
2922 port 80 on any other interface will only select among the third and fourth
2923 virtual hosts. In the common case where the interface isn't important
2924 to the mapping, only the "*:80" NameVirtualHost and VirtualHost directives
2927 <div class="example"><p><code>
2928 NameVirtualHost 192.0.2.1:80<br />
2929 NameVirtualHost *:80<br /><br />
2931 <VirtualHost 192.0.2.1:80><br />
2932 ServerName namebased-a.example.com<br />
2933 </VirtualHost><br />
2935 <VirtualHost 192.0.2.1:80><br />
2936 Servername namebased-b.example.com<br />
2937 </VirtualHost><br />
2939 <VirtualHost *:80><br />
2940 ServerName namebased-c.example.com <br />
2941 </VirtualHost><br />
2943 <VirtualHost *:80><br />
2944 ServerName namebased-d.example.com <br />
2945 </VirtualHost><br />
2950 <p>If no matching virtual host is found, then the first listed
2951 virtual host that matches the IP address and port will be used.</p>
2954 <p>IPv6 addresses must be enclosed in square brackets, as shown
2955 in the following example:</p>
2957 <div class="example"><p><code>
2958 NameVirtualHost [2001:db8::a00:20ff:fea7:ccea]:8080
2961 <div class="note"><h3>Argument to <code class="directive"><VirtualHost></code>
2963 <p>Note that the argument to the <code class="directive"><VirtualHost></code> directive must
2964 exactly match the argument to the <code class="directive">NameVirtualHost</code> directive.</p>
2966 <div class="example"><p><code>
2967 NameVirtualHost 192.0.2.2:80<br />
2968 <VirtualHost 192.0.2.2:80><br />
2970 </VirtualHost><br />
2976 <li><a href="../vhosts/">Virtual Hosts
2977 documentation</a></li>
2980 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2981 <div class="directive-section"><h2><a name="Options" id="Options">Options</a> <a name="options" id="options">Directive</a></h2>
2982 <table class="directive">
2983 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures what features are available in a particular
2985 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Options
2986 [+|-]<var>option</var> [[+|-]<var>option</var>] ...</code></td></tr>
2987 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Options All</code></td></tr>
2988 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2989 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
2990 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2991 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2993 <p>The <code class="directive">Options</code> directive controls which
2994 server features are available in a particular directory.</p>
2996 <p><var>option</var> can be set to <code>None</code>, in which
2997 case none of the extra features are enabled, or one or more of
3001 <dt><code>All</code></dt>
3003 <dd>All options except for <code>MultiViews</code>. This is the default
3006 <dt><code>ExecCGI</code></dt>
3009 Execution of CGI scripts using <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>
3012 <dt><code>FollowSymLinks</code></dt>
3016 The server will follow symbolic links in this directory.
3018 <p>Even though the server follows the symlink it does <em>not</em>
3019 change the pathname used to match against <code class="directive"><a href="#directory"><Directory></a></code> sections.</p>
3020 <p>Note also, that this option <strong>gets ignored</strong> if set
3021 inside a <code class="directive"><a href="#location"><Location></a></code>
3023 <p>Omitting this option should not be considered a security restriction,
3024 since symlink testing is subject to race conditions that make it
3028 <dt><code>Includes</code></dt>
3031 Server-side includes provided by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
3034 <dt><code>IncludesNOEXEC</code></dt>
3038 Server-side includes are permitted, but the <code>#exec
3039 cmd</code> and <code>#exec cgi</code> are disabled. It is still
3040 possible to <code>#include virtual</code> CGI scripts from
3041 <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>ed
3044 <dt><code>Indexes</code></dt>
3047 If a URL which maps to a directory is requested, and there
3048 is no <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
3049 (<em>e.g.</em>, <code>index.html</code>) in that directory, then
3050 <code class="module"><a href="../mod/mod_autoindex.html">mod_autoindex</a></code> will return a formatted listing
3051 of the directory.</dd>
3053 <dt><code>MultiViews</code></dt>
3056 <a href="../content-negotiation.html">Content negotiated</a>
3057 "MultiViews" are allowed using
3058 <code class="module"><a href="../mod/mod_negotiation.html">mod_negotiation</a></code>.
3059 <div class="note"><h3>Note</h3> <p>This option gets ignored if set
3060 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>
3061 needs real resources to compare against and evaluate from.</p></div>
3064 <dt><code>SymLinksIfOwnerMatch</code></dt>
3066 <dd>The server will only follow symbolic links for which the
3067 target file or directory is owned by the same user id as the
3070 <div class="note"><h3>Note</h3> <p>This option gets ignored if
3071 set inside a <code class="directive"><a href="#location"><Location></a></code> section.</p>
3072 <p>This option should not be considered a security restriction,
3073 since symlink testing is subject to race conditions that make it
3074 circumventable.</p></div>
3078 <p>Normally, if multiple <code class="directive">Options</code> could
3079 apply to a directory, then the most specific one is used and
3080 others are ignored; the options are not merged. (See <a href="../sections.html#mergin">how sections are merged</a>.)
3081 However if <em>all</em> the options on the
3082 <code class="directive">Options</code> directive are preceded by a
3083 <code>+</code> or <code>-</code> symbol, the options are
3084 merged. Any options preceded by a <code>+</code> are added to the
3085 options currently in force, and any options preceded by a
3086 <code>-</code> are removed from the options currently in
3089 <div class="warning"><h3>Warning</h3>
3090 <p>Mixing <code class="directive">Options</code> with a <code>+</code> or
3091 <code>-</code> with those without is not valid syntax, and is likely
3092 to cause unexpected results.</p>
3095 <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>
3097 <div class="example"><p><code>
3098 <Directory /web/docs><br />
3099 <span class="indent">
3100 Options Indexes FollowSymLinks<br />
3102 </Directory><br />
3104 <Directory /web/docs/spec><br />
3105 <span class="indent">
3106 Options Includes<br />
3111 <p>then only <code>Includes</code> will be set for the
3112 <code>/web/docs/spec</code> directory. However if the second
3113 <code class="directive">Options</code> directive uses the <code>+</code> and
3114 <code>-</code> symbols:</p>
3116 <div class="example"><p><code>
3117 <Directory /web/docs><br />
3118 <span class="indent">
3119 Options Indexes FollowSymLinks<br />
3121 </Directory><br />
3123 <Directory /web/docs/spec><br />
3124 <span class="indent">
3125 Options +Includes -Indexes<br />
3130 <p>then the options <code>FollowSymLinks</code> and
3131 <code>Includes</code> are set for the <code>/web/docs/spec</code>
3134 <div class="note"><h3>Note</h3>
3135 <p>Using <code>-IncludesNOEXEC</code> or
3136 <code>-Includes</code> disables server-side includes completely
3137 regardless of the previous setting.</p>
3140 <p>The default in the absence of any other settings is
3141 <code>All</code>.</p>
3144 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3145 <div class="directive-section"><h2><a name="Protocol" id="Protocol">Protocol</a> <a name="protocol" id="protocol">Directive</a></h2>
3146 <table class="directive">
3147 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Protocol for a listening socket</td></tr>
3148 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Protocol <var>protocol</var></code></td></tr>
3149 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</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 2.1.5 and later.
3153 On Windows from Apache 2.3.3 and later.</td></tr>
3155 <p>This directive specifies the protocol used for a specific listening socket.
3156 The protocol is used to determine which module should handle a request, and
3157 to apply protocol specific optimizations with the <code class="directive">AcceptFilter</code>
3160 <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>
3162 <p>For example, if you are running <code>https</code> on a non-standard port, specify the protocol explicitly:</p>
3164 <div class="example"><p><code>
3168 <p>You can also specify the protocol using the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code> directive.</p>
3172 <li><code class="directive">AcceptFilter</code></li>
3173 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
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="RLimitCPU" id="RLimitCPU">RLimitCPU</a> <a name="rlimitcpu" id="rlimitcpu">Directive</a></h2>
3178 <table class="directive">
3179 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the CPU consumption of processes launched
3180 by Apache httpd children</td></tr>
3181 <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>
3182 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3183 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3184 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3185 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3186 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3188 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3189 resource limit for all processes and the second parameter sets
3190 the maximum resource limit. Either parameter can be a number,
3191 or <code>max</code> to indicate to the server that the limit should
3192 be set to the maximum allowed by the operating system
3193 configuration. Raising the maximum resource limit requires that
3194 the server is running as <code>root</code>, or in the initial startup
3197 <p>This applies to processes forked off from Apache httpd children
3198 servicing requests, not the Apache httpd children themselves. This
3199 includes CGI scripts and SSI exec commands, but not any
3200 processes forked off from the Apache httpd parent such as piped
3203 <p>CPU resource limits are expressed in seconds per
3208 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3209 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3212 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3213 <div class="directive-section"><h2><a name="RLimitMEM" id="RLimitMEM">RLimitMEM</a> <a name="rlimitmem" id="rlimitmem">Directive</a></h2>
3214 <table class="directive">
3215 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the memory consumption of processes launched
3216 by Apache httpd children</td></tr>
3217 <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>
3218 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3219 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3220 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3221 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3222 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3224 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3225 resource limit for all processes and the second parameter sets
3226 the maximum resource limit. Either parameter can be a number,
3227 or <code>max</code> to indicate to the server that the limit should
3228 be set to the maximum allowed by the operating system
3229 configuration. Raising the maximum resource limit requires that
3230 the server is running as <code>root</code>, or in the initial startup
3233 <p>This applies to processes forked off from Apache httpd children
3234 servicing requests, not the Apache httpd children themselves. This
3235 includes CGI scripts and SSI exec commands, but not any
3236 processes forked off from the Apache httpd parent such as piped
3239 <p>Memory resource limits are expressed in bytes per
3244 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3245 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3248 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3249 <div class="directive-section"><h2><a name="RLimitNPROC" id="RLimitNPROC">RLimitNPROC</a> <a name="rlimitnproc" id="rlimitnproc">Directive</a></h2>
3250 <table class="directive">
3251 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of processes that can be launched by
3252 processes launched by Apache httpd children</td></tr>
3253 <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>
3254 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3255 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3256 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3257 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3258 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3260 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3261 resource limit for all processes and the second parameter sets
3262 the maximum resource limit. Either parameter can be a number,
3263 or <code>max</code> to indicate to the server that the limit
3264 should be set to the maximum allowed by the operating system
3265 configuration. Raising the maximum resource limit requires that
3266 the server is running as <code>root</code>, or in the initial startup
3269 <p>This applies to processes forked off from Apache httpd children
3270 servicing requests, not the Apache httpd children themselves. This
3271 includes CGI scripts and SSI exec commands, but not any
3272 processes forked off from the Apache httpd parent such as piped
3275 <p>Process limits control the number of processes per user.</p>
3277 <div class="note"><h3>Note</h3>
3278 <p>If CGI processes are <strong>not</strong> running
3279 under user ids other than the web server user id, this directive
3280 will limit the number of processes that the server itself can
3281 create. Evidence of this situation will be indicated by
3282 <strong><code>cannot fork</code></strong> messages in the
3283 <code>error_log</code>.</p>
3288 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3289 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3292 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3293 <div class="directive-section"><h2><a name="ScriptInterpreterSource" id="ScriptInterpreterSource">ScriptInterpreterSource</a> <a name="scriptinterpretersource" id="scriptinterpretersource">Directive</a></h2>
3294 <table class="directive">
3295 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
3297 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ScriptInterpreterSource Registry|Registry-Strict|Script</code></td></tr>
3298 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ScriptInterpreterSource Script</code></td></tr>
3299 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3300 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3301 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3302 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3303 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Win32 only;
3304 option <code>Registry-Strict</code> is available in Apache HTTP Server 2.0 and
3307 <p>This directive is used to control how Apache httpd finds the
3308 interpreter used to run CGI scripts. The default setting is
3309 <code>Script</code>. This causes Apache httpd to use the interpreter pointed to
3310 by the shebang line (first line, starting with <code>#!</code>) in the
3311 script. On Win32 systems this line usually looks like:</p>
3313 <div class="example"><p><code>
3314 #!C:/Perl/bin/perl.exe
3317 <p>or, if <code>perl</code> is in the <code>PATH</code>, simply:</p>
3319 <div class="example"><p><code>
3323 <p>Setting <code>ScriptInterpreterSource Registry</code> will
3324 cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
3325 searched using the script file extension (e.g., <code>.pl</code>) as a
3326 search key. The command defined by the registry subkey
3327 <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
3328 <code>Shell\Open\Command</code> is used to open the script file. If the
3329 registry keys cannot be found, Apache httpd falls back to the behavior of the
3330 <code>Script</code> option.</p>
3332 <div class="warning"><h3>Security</h3>
3333 <p>Be careful when using <code>ScriptInterpreterSource
3334 Registry</code> with <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>'ed directories, because
3335 Apache httpd will try to execute <strong>every</strong> file within this
3336 directory. The <code>Registry</code> setting may cause undesired
3337 program calls on files which are typically not executed. For
3338 example, the default open command on <code>.htm</code> files on
3339 most Windows systems will execute Microsoft Internet Explorer, so
3340 any HTTP request for an <code>.htm</code> file existing within the
3341 script directory would start the browser in the background on the
3342 server. This is a good way to crash your system within a minute or
3346 <p>The option <code>Registry-Strict</code> which is new in Apache HTTP Server
3347 2.0 does the same thing as <code>Registry</code> but uses only the
3348 subkey <code>Shell\ExecCGI\Command</code>. The
3349 <code>ExecCGI</code> key is not a common one. It must be
3350 configured manually in the windows registry and hence prevents
3351 accidental program calls on your system.</p>
3354 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3355 <div class="directive-section"><h2><a name="SeeRequestTail" id="SeeRequestTail">SeeRequestTail</a> <a name="seerequesttail" id="seerequesttail">Directive</a></h2>
3356 <table class="directive">
3357 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine if mod_status displays the first 63 characters
3358 of a request or the last 63, assuming the request itself is greater than
3360 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SeeRequestTail On|Off</code></td></tr>
3361 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SeeRequestTail Off</code></td></tr>
3362 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3363 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3364 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3365 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.2.7 and later.</td></tr>
3367 <p>mod_status with <code>ExtendedStatus On</code>
3368 displays the actual request being handled.
3369 For historical purposes, only 63 characters of the request
3370 are actually stored for display purposes. This directive
3371 controls whether the 1st 63 characters are stored (the previous
3372 behavior and the default) or if the last 63 characters are. This
3373 is only applicable, of course, if the length of the request is
3374 64 characters or greater.</p>
3376 <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:
3379 <table class="bordered">
3381 <th>Off (default)</th>
3382 <td>GET /disk1/storage/apache/htdocs/images/imagestore1/food/apples</td>
3386 <td>orage/apache/htdocs/images/imagestore1/food/apples.jpg HTTP/1.1</td>
3392 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3393 <div class="directive-section"><h2><a name="ServerAdmin" id="ServerAdmin">ServerAdmin</a> <a name="serveradmin" id="serveradmin">Directive</a></h2>
3394 <table class="directive">
3395 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Email address that the server includes in error
3396 messages sent to the client</td></tr>
3397 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAdmin <var>email-address</var>|<var>URL</var></code></td></tr>
3398 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3399 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3400 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3402 <p>The <code class="directive">ServerAdmin</code> sets the contact address
3403 that the server includes in any error messages it returns to the
3404 client. If the <code>httpd</code> doesn't recognize the supplied argument
3406 assumes, that it's an <var>email-address</var> and prepends it with
3407 <code>mailto:</code> in hyperlink targets. However, it's recommended to
3408 actually use an email address, since there are a lot of CGI scripts that
3409 make that assumption. If you want to use an URL, it should point to another
3410 server under your control. Otherwise users may not be able to contact you in
3413 <p>It may be worth setting up a dedicated address for this, e.g.</p>
3415 <div class="example"><p><code>
3416 ServerAdmin www-admin@foo.example.com
3418 <p>as users do not always mention that they are talking about the
3422 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3423 <div class="directive-section"><h2><a name="ServerAlias" id="ServerAlias">ServerAlias</a> <a name="serveralias" id="serveralias">Directive</a></h2>
3424 <table class="directive">
3425 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Alternate names for a host used when matching requests
3426 to name-virtual hosts</td></tr>
3427 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</code></td></tr>
3428 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
3429 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3430 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3432 <p>The <code class="directive">ServerAlias</code> directive sets the
3433 alternate names for a host, for use with <a href="../vhosts/name-based.html">name-based virtual hosts</a>. The
3434 <code class="directive">ServerAlias</code> may include wildcards, if appropriate.</p>
3436 <div class="example"><p><code>
3437 <VirtualHost *:80><br />
3438 ServerName server.domain.com<br />
3439 ServerAlias server server2.domain.com server2<br />
3440 ServerAlias *.example.com<br />
3441 UseCanonicalName Off<br />
3443 </VirtualHost>
3448 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3449 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
3452 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3453 <div class="directive-section"><h2><a name="ServerName" id="ServerName">ServerName</a> <a name="servername" id="servername">Directive</a></h2>
3454 <table class="directive">
3455 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hostname and port that the server uses to identify
3457 <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>
3458 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3459 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3460 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3462 <p>The <code class="directive">ServerName</code> directive sets the
3463 request scheme, hostname and
3464 port that the server uses to identify itself. This is used when
3465 creating redirection URLs.</p>
3467 <p>Additionally, <code class="directive">ServerName</code> is used (possibly
3468 in conjunction with <code class="directive">ServerAlias</code>) to uniquely
3469 identify a virtual host, when using <a href="../vhosts/name-based.html">name-based virtual hosts</a>.</p>
3471 <p>For example, if the name of the
3472 machine hosting the web server is <code>simple.example.com</code>,
3473 but the machine also has the DNS alias <code>www.example.com</code>
3474 and you wish the web server to be so identified, the following
3475 directive should be used:</p>
3477 <div class="example"><p><code>
3478 ServerName www.example.com:80
3481 <p>The <code class="directive">ServerName</code> directive
3482 may appear anywhere within the definition of a server. However,
3483 each appearance overrides the previous appearance (within that
3486 <p>If no <code class="directive">ServerName</code> is specified, then the
3487 server attempts to deduce the hostname by performing a reverse
3488 lookup on the IP address. If no port is specified in the
3489 <code class="directive">ServerName</code>, then the server will use the
3490 port from the incoming request. For optimal reliability and
3491 predictability, you should specify an explicit hostname and port
3492 using the <code class="directive">ServerName</code> directive.</p>
3494 <p>If you are using <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
3495 the <code class="directive">ServerName</code> inside a
3496 <code class="directive"><a href="#virtualhost"><VirtualHost></a></code>
3497 section specifies what hostname must appear in the request's
3498 <code>Host:</code> header to match this virtual host.</p>
3500 <p>Sometimes, the server runs behind a device that processes SSL,
3501 such as a reverse proxy, load balancer or SSL offload
3502 appliance. When this is the case, specify the
3503 <code>https://</code> scheme and the port number to which the
3504 clients connect in the <code class="directive">ServerName</code> directive
3505 to make sure that the server generates the correct
3506 self-referential URLs.
3509 <p>See the description of the
3510 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> and
3511 <code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code> directives for
3512 settings which determine whether self-referential URLs (e.g., by the
3513 <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> module) will refer to the
3514 specified port, or to the port number given in the client's request.
3517 <div class="warning">
3518 <p>Failure to set <code class="directive">ServerName</code> to a name that
3519 your server can resolve to an IP address will result in a startup
3520 warning. <code>httpd</code> will then use whatever hostname it can
3521 determine, using the system's <code>hostname</code> command. This
3522 will almost never be the hostname you actually want.</p>
3523 <div class="example"><p><code>
3524 httpd: Could not reliably determine the server's fully qualified domain name, using rocinante.local for ServerName
3531 <li><a href="../dns-caveats.html">Issues Regarding DNS and
3532 Apache HTTP Server</a></li>
3533 <li><a href="../vhosts/">Apache HTTP Server virtual host
3534 documentation</a></li>
3535 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3536 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
3537 <li><code class="directive"><a href="#namevirtualhost">NameVirtualHost</a></code></li>
3538 <li><code class="directive"><a href="#serveralias">ServerAlias</a></code></li>
3541 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3542 <div class="directive-section"><h2><a name="ServerPath" id="ServerPath">ServerPath</a> <a name="serverpath" id="serverpath">Directive</a></h2>
3543 <table class="directive">
3544 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Legacy URL pathname for a name-based virtual host that
3545 is accessed by an incompatible browser</td></tr>
3546 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerPath <var>URL-path</var></code></td></tr>
3547 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
3548 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3549 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3551 <p>The <code class="directive">ServerPath</code> directive sets the legacy
3552 URL pathname for a host, for use with <a href="../vhosts/">name-based virtual hosts</a>.</p>
3556 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
3559 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3560 <div class="directive-section"><h2><a name="ServerRoot" id="ServerRoot">ServerRoot</a> <a name="serverroot" id="serverroot">Directive</a></h2>
3561 <table class="directive">
3562 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server installation</td></tr>
3563 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerRoot <var>directory-path</var></code></td></tr>
3564 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerRoot /usr/local/apache</code></td></tr>
3565 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3566 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3567 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3569 <p>The <code class="directive">ServerRoot</code> directive sets the
3570 directory in which the server lives. Typically it will contain the
3571 subdirectories <code>conf/</code> and <code>logs/</code>. Relative
3572 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
3573 relative to this directory.</p>
3575 <div class="example"><h3>Example</h3><p><code>
3576 ServerRoot /home/httpd
3582 <li><a href="../invoking.html">the <code>-d</code>
3583 option to <code>httpd</code></a></li>
3584 <li><a href="../misc/security_tips.html#serverroot">the
3585 security tips</a> for information on how to properly set
3586 permissions on the <code class="directive">ServerRoot</code></li>
3589 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3590 <div class="directive-section"><h2><a name="ServerSignature" id="ServerSignature">ServerSignature</a> <a name="serversignature" id="serversignature">Directive</a></h2>
3591 <table class="directive">
3592 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the footer on server-generated documents</td></tr>
3593 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerSignature On|Off|EMail</code></td></tr>
3594 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerSignature Off</code></td></tr>
3595 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3596 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3597 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3598 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3600 <p>The <code class="directive">ServerSignature</code> directive allows the
3601 configuration of a trailing footer line under server-generated
3602 documents (error messages, <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> ftp directory
3603 listings, <code class="module"><a href="../mod/mod_info.html">mod_info</a></code> output, ...). The reason why you
3604 would want to enable such a footer line is that in a chain of proxies,
3605 the user often has no possibility to tell which of the chained servers
3606 actually produced a returned error message.</p>
3608 <p>The <code>Off</code>
3609 setting, which is the default, suppresses the footer line (and is
3610 therefore compatible with the behavior of Apache-1.2 and
3611 below). The <code>On</code> setting simply adds a line with the
3612 server version number and <code class="directive"><a href="#servername">ServerName</a></code> of the serving virtual host,
3613 and the <code>EMail</code> setting additionally creates a
3614 "mailto:" reference to the <code class="directive"><a href="#serveradmin">ServerAdmin</a></code> of the referenced
3617 <p>After version 2.0.44, the details of the server version number
3618 presented are controlled by the <code class="directive"><a href="#servertokens">ServerTokens</a></code> directive.</p>
3622 <li><code class="directive"><a href="#servertokens">ServerTokens</a></code></li>
3625 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3626 <div class="directive-section"><h2><a name="ServerTokens" id="ServerTokens">ServerTokens</a> <a name="servertokens" id="servertokens">Directive</a></h2>
3627 <table class="directive">
3628 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the <code>Server</code> HTTP response
3630 <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>
3631 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerTokens Full</code></td></tr>
3632 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3633 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3634 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3636 <p>This directive controls whether <code>Server</code> response
3637 header field which is sent back to clients includes a
3638 description of the generic OS-type of the server as well as
3639 information about compiled-in modules.</p>
3642 <dt><code>ServerTokens Full</code> (or not specified)</dt>
3644 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.1
3645 (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
3647 <dt><code>ServerTokens Prod[uctOnly]</code></dt>
3649 <dd>Server sends (<em>e.g.</em>): <code>Server:
3652 <dt><code>ServerTokens Major</code></dt>
3654 <dd>Server sends (<em>e.g.</em>): <code>Server:
3655 Apache/2</code></dd>
3657 <dt><code>ServerTokens Minor</code></dt>
3659 <dd>Server sends (<em>e.g.</em>): <code>Server:
3660 Apache/2.4</code></dd>
3662 <dt><code>ServerTokens Min[imal]</code></dt>
3664 <dd>Server sends (<em>e.g.</em>): <code>Server:
3665 Apache/2.4.1</code></dd>
3667 <dt><code>ServerTokens OS</code></dt>
3669 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.1
3674 <p>This setting applies to the entire server, and cannot be
3675 enabled or disabled on a virtualhost-by-virtualhost basis.</p>
3677 <p>After version 2.0.44, this directive also controls the
3678 information presented by the <code class="directive"><a href="#serversignature">ServerSignature</a></code> directive.</p>
3680 <div class="note">Setting <code class="directive">ServerTokens</code> to less than
3681 <code>minimal</code> is not recommended because it makes it more
3682 difficult to debug interoperational problems. Also note that
3683 disabling the Server: header does nothing at all to make your
3684 server more secure; the idea of "security through obscurity"
3685 is a myth and leads to a false sense of safety.</div>
3690 <li><code class="directive"><a href="#serversignature">ServerSignature</a></code></li>
3693 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3694 <div class="directive-section"><h2><a name="SetHandler" id="SetHandler">SetHandler</a> <a name="sethandler" id="sethandler">Directive</a></h2>
3695 <table class="directive">
3696 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be processed by a
3698 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetHandler <var>handler-name</var>|None</code></td></tr>
3699 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3700 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3701 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3702 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3703 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Moved into the core in Apache httpd 2.0</td></tr>
3705 <p>When placed into an <code>.htaccess</code> file or a
3706 <code class="directive"><a href="#directory"><Directory></a></code> or
3707 <code class="directive"><a href="#location"><Location></a></code>
3708 section, this directive forces all matching files to be parsed
3709 through the <a href="../handler.html">handler</a> given by
3710 <var>handler-name</var>. For example, if you had a directory you
3711 wanted to be parsed entirely as imagemap rule files, regardless
3712 of extension, you might put the following into an
3713 <code>.htaccess</code> file in that directory:</p>
3715 <div class="example"><p><code>
3716 SetHandler imap-file
3719 <p>Another example: if you wanted to have the server display a
3720 status report whenever a URL of
3721 <code>http://servername/status</code> was called, you might put
3722 the following into <code>httpd.conf</code>:</p>
3724 <div class="example"><p><code>
3725 <Location /status><br />
3726 <span class="indent">
3727 SetHandler server-status<br />
3732 <p>You can override an earlier defined <code class="directive">SetHandler</code>
3733 directive by using the value <code>None</code>.</p>
3734 <p><strong>Note:</strong> because SetHandler overrides default handlers,
3735 normal behaviour such as handling of URLs ending in a slash (/) as
3736 directories or index files is suppressed.</p>
3740 <li><code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code></li>
3743 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3744 <div class="directive-section"><h2><a name="SetInputFilter" id="SetInputFilter">SetInputFilter</a> <a name="setinputfilter" id="setinputfilter">Directive</a></h2>
3745 <table class="directive">
3746 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process client requests and POST
3748 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetInputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
3749 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3750 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3751 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3752 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3754 <p>The <code class="directive">SetInputFilter</code> directive sets the
3755 filter or filters which will process client requests and POST
3756 input when they are received by the server. This is in addition to
3757 any filters defined elsewhere, including the
3758 <code class="directive"><a href="../mod/mod_mime.html#addinputfilter">AddInputFilter</a></code>
3761 <p>If more than one filter is specified, they must be separated
3762 by semicolons in the order in which they should process the
3767 <li><a href="../filter.html">Filters</a> documentation</li>
3770 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3771 <div class="directive-section"><h2><a name="SetOutputFilter" id="SetOutputFilter">SetOutputFilter</a> <a name="setoutputfilter" id="setoutputfilter">Directive</a></h2>
3772 <table class="directive">
3773 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process responses from the
3775 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
3776 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3777 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3778 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3779 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3781 <p>The <code class="directive">SetOutputFilter</code> directive sets the filters
3782 which will process responses from the server before they are
3783 sent to the client. This is in addition to any filters defined
3784 elsewhere, including the
3785 <code class="directive"><a href="../mod/mod_mime.html#addoutputfilter">AddOutputFilter</a></code>
3788 <p>For example, the following configuration will process all files
3789 in the <code>/www/data/</code> directory for server-side
3792 <div class="example"><p><code>
3793 <Directory /www/data/><br />
3794 <span class="indent">
3795 SetOutputFilter INCLUDES<br />
3800 <p>If more than one filter is specified, they must be separated
3801 by semicolons in the order in which they should process the
3806 <li><a href="../filter.html">Filters</a> documentation</li>
3809 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3810 <div class="directive-section"><h2><a name="TimeOut" id="TimeOut">TimeOut</a> <a name="timeout" id="timeout">Directive</a></h2>
3811 <table class="directive">
3812 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for
3813 certain events before failing a request</td></tr>
3814 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TimeOut <var>seconds</var></code></td></tr>
3815 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TimeOut 300</code></td></tr>
3816 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3817 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3818 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3820 <p>The <code class="directive">TimeOut</code> directive defines the length
3821 of time Apache httpd will wait for I/O in various circumstances:</p>
3824 <li>When reading data from the client, the length of time to
3825 wait for a TCP packet to arrive if the read buffer is
3828 <li>When writing data to the client, the length of time to wait
3829 for an acknowledgement of a packet if the send buffer is
3832 <li>In <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>, the length of time to wait for
3833 output from a CGI script.</li>
3835 <li>In <code class="module"><a href="../mod/mod_ext_filter.html">mod_ext_filter</a></code>, the length of time to
3836 wait for output from a filtering process.</li>
3838 <li>In <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>, the default timeout value if
3839 <code class="directive"><a href="../mod/mod_proxy.html#proxytimeout">ProxyTimeout</a></code> is not
3845 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3846 <div class="directive-section"><h2><a name="TraceEnable" id="TraceEnable">TraceEnable</a> <a name="traceenable" id="traceenable">Directive</a></h2>
3847 <table class="directive">
3848 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines the behaviour on <code>TRACE</code> requests</td></tr>
3849 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TraceEnable <var>[on|off|extended]</var></code></td></tr>
3850 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TraceEnable on</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>
3854 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 1.3.34, 2.0.55 and later</td></tr>
3856 <p>This directive overrides the behavior of <code>TRACE</code> for both
3857 the core server and <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>. The default
3858 <code>TraceEnable on</code> permits <code>TRACE</code> requests per
3859 RFC 2616, which disallows any request body to accompany the request.
3860 <code>TraceEnable off</code> causes the core server and
3861 <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> to return a <code>405</code> (Method not
3862 allowed) error to the client.</p>
3864 <p>Finally, for testing and diagnostic purposes only, request
3865 bodies may be allowed using the non-compliant <code>TraceEnable
3866 extended</code> directive. The core (as an origin server) will
3867 restrict the request body to 64k (plus 8k for chunk headers if
3868 <code>Transfer-Encoding: chunked</code> is used). The core will
3869 reflect the full headers and all chunk headers with the response
3870 body. As a proxy server, the request body is not restricted to 64k.</p>
3873 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3874 <div class="directive-section"><h2><a name="UnDefine" id="UnDefine">UnDefine</a> <a name="undefine" id="undefine">Directive</a></h2>
3875 <table class="directive">
3876 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Undefine the existence of a variable</td></tr>
3877 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UnDefine <var>parameter-name</var></code></td></tr>
3878 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3879 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3880 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3882 <p>Undoes the effect of a <code class="directive"><a href="#define">Define</a></code> or
3883 of passing a <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</p>
3884 <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
3885 <code>-D</code> arguments in any startup scripts.</p>
3888 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3889 <div class="directive-section"><h2><a name="UseCanonicalName" id="UseCanonicalName">UseCanonicalName</a> <a name="usecanonicalname" id="usecanonicalname">Directive</a></h2>
3890 <table class="directive">
3891 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own name and
3893 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalName On|Off|DNS</code></td></tr>
3894 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalName Off</code></td></tr>
3895 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3896 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3897 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3899 <p>In many situations Apache httpd must construct a <em>self-referential</em>
3900 URL -- that is, a URL that refers back to the same server. With
3901 <code>UseCanonicalName On</code> Apache httpd will use the hostname and port
3902 specified in the <code class="directive"><a href="#servername">ServerName</a></code>
3903 directive to construct the canonical name for the server. This name
3904 is used in all self-referential URLs, and for the values of
3905 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>
3907 <p>With <code>UseCanonicalName Off</code> Apache httpd will form
3908 self-referential URLs using the hostname and port supplied by
3909 the client if any are supplied (otherwise it will use the
3910 canonical name, as defined above). These values are the same
3911 that are used to implement <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
3912 and are available with the same clients. The CGI variables
3913 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
3914 constructed from the client supplied values as well.</p>
3916 <p>An example where this may be useful is on an intranet server
3917 where you have users connecting to the machine using short
3918 names such as <code>www</code>. You'll notice that if the users
3919 type a shortname, and a URL which is a directory, such as
3920 <code>http://www/splat</code>, <em>without the trailing
3921 slash</em> then Apache httpd will redirect them to
3922 <code>http://www.domain.com/splat/</code>. If you have
3923 authentication enabled, this will cause the user to have to
3924 authenticate twice (once for <code>www</code> and once again
3925 for <code>www.domain.com</code> -- see <a href="http://httpd.apache.org/docs/misc/FAQ.html#prompted-twice">the
3926 FAQ on this subject for more information</a>). But if
3927 <code class="directive">UseCanonicalName</code> is set <code>Off</code>, then
3928 Apache httpd will redirect to <code>http://www/splat/</code>.</p>
3930 <p>There is a third option, <code>UseCanonicalName DNS</code>,
3931 which is intended for use with mass IP-based virtual hosting to
3932 support ancient clients that do not provide a
3933 <code>Host:</code> header. With this option Apache httpd does a
3934 reverse DNS lookup on the server IP address that the client
3935 connected to in order to work out self-referential URLs.</p>
3937 <div class="warning"><h3>Warning</h3>
3938 <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>
3939 they may be broken by this option. The client is essentially free
3940 to give whatever value they want as a hostname. But if the CGI is
3941 only using <code>SERVER_NAME</code> to construct self-referential URLs
3942 then it should be just fine.</p>
3947 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
3948 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
3949 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
3952 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3953 <div class="directive-section"><h2><a name="UseCanonicalPhysicalPort" id="UseCanonicalPhysicalPort">UseCanonicalPhysicalPort</a> <a name="usecanonicalphysicalport" id="usecanonicalphysicalport">Directive</a></h2>
3954 <table class="directive">
3955 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own name and
3957 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalPhysicalPort On|Off</code></td></tr>
3958 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalPhysicalPort Off</code></td></tr>
3959 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3960 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3961 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3963 <p>In many situations Apache httpd must construct a <em>self-referential</em>
3964 URL -- that is, a URL that refers back to the same server. With
3965 <code>UseCanonicalPhysicalPort On</code> Apache httpd will, when
3966 constructing the canonical port for the server to honor
3967 the <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> directive,
3968 provide the actual physical port number being used by this request
3969 as a potential port. With <code>UseCanonicalPhysicalPort Off</code>
3970 Apache httpd will not ever use the actual physical port number, instead
3971 relying on all configured information to construct a valid port number.</p>
3973 <div class="note"><h3>Note</h3>
3974 <p>The ordering of when the physical port is used is as follows:<br /><br />
3975 <code>UseCanonicalName On</code></p>
3977 <li>Port provided in <code>Servername</code></li>
3978 <li>Physical port</li>
3979 <li>Default port</li>
3981 <code>UseCanonicalName Off | DNS</code>
3983 <li>Parsed port from <code>Host:</code> header</li>
3984 <li>Physical port</li>
3985 <li>Port provided in <code>Servername</code></li>
3986 <li>Default port</li>
3989 <p>With <code>UseCanonicalPhysicalPort Off</code>, the
3990 physical ports are removed from the ordering.</p>
3996 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3997 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
3998 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4001 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4002 <div class="directive-section"><h2><a name="VirtualHost" id="VirtualHost"><VirtualHost></a> <a name="virtualhost" id="virtualhost">Directive</a></h2>
4003 <table class="directive">
4004 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only to a specific
4005 hostname or IP address</td></tr>
4006 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><VirtualHost
4007 <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
4008 ...> ... </VirtualHost></code></td></tr>
4009 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4010 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4011 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4013 <p><code class="directive"><VirtualHost></code> and
4014 <code></VirtualHost></code> are used to enclose a group of
4015 directives that will apply only to a particular virtual host. Any
4016 directive that is allowed in a virtual host context may be
4017 used. When the server receives a request for a document on a
4018 particular virtual host, it uses the configuration directives
4019 enclosed in the <code class="directive"><VirtualHost></code>
4020 section. <var>Addr</var> can be:</p>
4023 <li>The IP address of the virtual host;</li>
4025 <li>A fully qualified domain name for the IP address of the
4026 virtual host (not recommended);</li>
4028 <li>The character <code>*</code>, which is used only in combination with
4029 <code>NameVirtualHost *</code> to match all IP addresses; or</li>
4031 <li>The string <code>_default_</code>, which is used only
4032 with IP virtual hosting to catch unmatched IP addresses.</li>
4035 <div class="example"><h3>Example</h3><p><code>
4036 <VirtualHost 10.1.2.3><br />
4037 <span class="indent">
4038 ServerAdmin webmaster@host.example.com<br />
4039 DocumentRoot /www/docs/host.example.com<br />
4040 ServerName host.example.com<br />
4041 ErrorLog logs/host.example.com-error_log<br />
4042 TransferLog logs/host.example.com-access_log<br />
4044 </VirtualHost>
4048 <p>IPv6 addresses must be specified in square brackets because
4049 the optional port number could not be determined otherwise. An
4050 IPv6 example is shown below:</p>
4052 <div class="example"><p><code>
4053 <VirtualHost [2001:db8::a00:20ff:fea7:ccea]><br />
4054 <span class="indent">
4055 ServerAdmin webmaster@host.example.com<br />
4056 DocumentRoot /www/docs/host.example.com<br />
4057 ServerName host.example.com<br />
4058 ErrorLog logs/host.example.com-error_log<br />
4059 TransferLog logs/host.example.com-access_log<br />
4061 </VirtualHost>
4064 <p>Each Virtual Host must correspond to a different IP address,
4065 different port number or a different host name for the server,
4066 in the former case the server machine must be configured to
4067 accept IP packets for multiple addresses. (If the machine does
4068 not have multiple network interfaces, then this can be
4069 accomplished with the <code>ifconfig alias</code> command -- if
4070 your OS supports it).</p>
4072 <div class="note"><h3>Note</h3>
4073 <p>The use of <code class="directive"><VirtualHost></code> does
4074 <strong>not</strong> affect what addresses Apache httpd listens on. You
4075 may need to ensure that Apache httpd is listening on the correct addresses
4076 using <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>.</p>
4079 <p>When using IP-based virtual hosting, the special name
4080 <code>_default_</code> can be specified in
4081 which case this virtual host will match any IP address that is
4082 not explicitly listed in another virtual host. In the absence
4083 of any <code>_default_</code> virtual host the "main" server config,
4084 consisting of all those definitions outside any VirtualHost
4085 section, is used when no IP-match occurs.</p>
4087 <p>You can specify a <code>:port</code> to change the port that is
4088 matched. If unspecified then it defaults to the same port as the
4089 most recent <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>
4090 statement of the main server. You may also specify <code>:*</code>
4091 to match all ports on that address. (This is recommended when used
4092 with <code>_default_</code>.)</p>
4094 <p>A <code class="directive"><a href="#servername">ServerName</a></code> should be
4095 specified inside each <code class="directive"><VirtualHost></code> block. If it is absent, the
4096 <code class="directive"><a href="#servername">ServerName</a></code> from the "main"
4097 server configuration will be inherited.</p>
4099 <p>If no matching virtual host is found, then the first listed
4100 virtual host that matches the IP address will be used. As a
4101 consequence, the first listed virtual host is the default virtual
4104 <div class="warning"><h3>Security</h3>
4105 <p>See the <a href="../misc/security_tips.html">security tips</a>
4106 document for details on why your security could be compromised if the
4107 directory where log files are stored is writable by anyone other
4108 than the user that starts the server.</p>
4113 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4114 <li><a href="../dns-caveats.html">Issues Regarding DNS and
4115 Apache HTTP Server</a></li>
4116 <li><a href="../bind.html">Setting
4117 which addresses and ports Apache HTTP Server uses</a></li>
4118 <li><a href="../sections.html">How <Directory>, <Location>
4119 and <Files> sections work</a> for an explanation of how these
4120 different sections are combined when a request is received</li>
4124 <div class="bottomlang">
4125 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
4126 <a href="../en/mod/core.html" title="English"> en </a> |
4127 <a href="../es/mod/core.html" hreflang="es" rel="alternate" title="Español"> es </a> |
4128 <a href="../fr/mod/core.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
4129 <a href="../ja/mod/core.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
4130 <a href="../tr/mod/core.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p>
4131 </div><div id="footer">
4132 <p class="apache">Copyright 2010 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>
4133 <p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div>
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