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18 <p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p>
19 <p class="apache">Apache HTTP Server Version 2.5</p>
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23 <a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.5</a> > <a href="./">Modules</a></div>
24 <div id="page-content">
25 <div id="preamble"><h1>Apache Core Features</h1>
27 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
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34 <table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Core Apache HTTP Server features that are always
36 <tr><th><a href="module-dict.html#Status">Status:</a></th><td>Core</td></tr></table>
38 <div id="quickview"><h3 class="directives">Directives</h3>
40 <li><img alt="" src="../images/down.gif" /> <a href="#acceptfilter">AcceptFilter</a></li>
41 <li><img alt="" src="../images/down.gif" /> <a href="#acceptpathinfo">AcceptPathInfo</a></li>
42 <li><img alt="" src="../images/down.gif" /> <a href="#accessfilename">AccessFileName</a></li>
43 <li><img alt="" src="../images/down.gif" /> <a href="#adddefaultcharset">AddDefaultCharset</a></li>
44 <li><img alt="" src="../images/down.gif" /> <a href="#allowencodedslashes">AllowEncodedSlashes</a></li>
45 <li><img alt="" src="../images/down.gif" /> <a href="#allowoverride">AllowOverride</a></li>
46 <li><img alt="" src="../images/down.gif" /> <a href="#allowoverridelist">AllowOverrideList</a></li>
47 <li><img alt="" src="../images/down.gif" /> <a href="#cgimapextension">CGIMapExtension</a></li>
48 <li><img alt="" src="../images/down.gif" /> <a href="#contentdigest">ContentDigest</a></li>
49 <li><img alt="" src="../images/down.gif" /> <a href="#defaultruntimedir">DefaultRuntimeDir</a></li>
50 <li><img alt="" src="../images/down.gif" /> <a href="#defaulttype">DefaultType</a></li>
51 <li><img alt="" src="../images/down.gif" /> <a href="#define">Define</a></li>
52 <li><img alt="" src="../images/down.gif" /> <a href="#directory"><Directory></a></li>
53 <li><img alt="" src="../images/down.gif" /> <a href="#directorymatch"><DirectoryMatch></a></li>
54 <li><img alt="" src="../images/down.gif" /> <a href="#documentroot">DocumentRoot</a></li>
55 <li><img alt="" src="../images/down.gif" /> <a href="#else"><Else></a></li>
56 <li><img alt="" src="../images/down.gif" /> <a href="#elseif"><ElseIf></a></li>
57 <li><img alt="" src="../images/down.gif" /> <a href="#enablemmap">EnableMMAP</a></li>
58 <li><img alt="" src="../images/down.gif" /> <a href="#enablesendfile">EnableSendfile</a></li>
59 <li><img alt="" src="../images/down.gif" /> <a href="#error">Error</a></li>
60 <li><img alt="" src="../images/down.gif" /> <a href="#errordocument">ErrorDocument</a></li>
61 <li><img alt="" src="../images/down.gif" /> <a href="#errorlog">ErrorLog</a></li>
62 <li><img alt="" src="../images/down.gif" /> <a href="#errorlogformat">ErrorLogFormat</a></li>
63 <li><img alt="" src="../images/down.gif" /> <a href="#extendedstatus">ExtendedStatus</a></li>
64 <li><img alt="" src="../images/down.gif" /> <a href="#fileetag">FileETag</a></li>
65 <li><img alt="" src="../images/down.gif" /> <a href="#files"><Files></a></li>
66 <li><img alt="" src="../images/down.gif" /> <a href="#filesmatch"><FilesMatch></a></li>
67 <li><img alt="" src="../images/down.gif" /> <a href="#forcetype">ForceType</a></li>
68 <li><img alt="" src="../images/down.gif" /> <a href="#gprofdir">GprofDir</a></li>
69 <li><img alt="" src="../images/down.gif" /> <a href="#hostnamelookups">HostnameLookups</a></li>
70 <li><img alt="" src="../images/down.gif" /> <a href="#if"><If></a></li>
71 <li><img alt="" src="../images/down.gif" /> <a href="#ifdefine"><IfDefine></a></li>
72 <li><img alt="" src="../images/down.gif" /> <a href="#ifmodule"><IfModule></a></li>
73 <li><img alt="" src="../images/down.gif" /> <a href="#include">Include</a></li>
74 <li><img alt="" src="../images/down.gif" /> <a href="#includeoptional">IncludeOptional</a></li>
75 <li><img alt="" src="../images/down.gif" /> <a href="#keepalive">KeepAlive</a></li>
76 <li><img alt="" src="../images/down.gif" /> <a href="#keepalivetimeout">KeepAliveTimeout</a></li>
77 <li><img alt="" src="../images/down.gif" /> <a href="#limit"><Limit></a></li>
78 <li><img alt="" src="../images/down.gif" /> <a href="#limitexcept"><LimitExcept></a></li>
79 <li><img alt="" src="../images/down.gif" /> <a href="#limitinternalrecursion">LimitInternalRecursion</a></li>
80 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestbody">LimitRequestBody</a></li>
81 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfields">LimitRequestFields</a></li>
82 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfieldsize">LimitRequestFieldSize</a></li>
83 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestline">LimitRequestLine</a></li>
84 <li><img alt="" src="../images/down.gif" /> <a href="#limitxmlrequestbody">LimitXMLRequestBody</a></li>
85 <li><img alt="" src="../images/down.gif" /> <a href="#location"><Location></a></li>
86 <li><img alt="" src="../images/down.gif" /> <a href="#locationmatch"><LocationMatch></a></li>
87 <li><img alt="" src="../images/down.gif" /> <a href="#loglevel">LogLevel</a></li>
88 <li><img alt="" src="../images/down.gif" /> <a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></li>
89 <li><img alt="" src="../images/down.gif" /> <a href="#maxrangeoverlaps">MaxRangeOverlaps</a></li>
90 <li><img alt="" src="../images/down.gif" /> <a href="#maxrangereversals">MaxRangeReversals</a></li>
91 <li><img alt="" src="../images/down.gif" /> <a href="#maxranges">MaxRanges</a></li>
92 <li><img alt="" src="../images/down.gif" /> <a href="#mutex">Mutex</a></li>
93 <li><img alt="" src="../images/down.gif" /> <a href="#namevirtualhost">NameVirtualHost</a></li>
94 <li><img alt="" src="../images/down.gif" /> <a href="#options">Options</a></li>
95 <li><img alt="" src="../images/down.gif" /> <a href="#protocol">Protocol</a></li>
96 <li><img alt="" src="../images/down.gif" /> <a href="#registerhttpmethod">RegisterHttpMethod</a></li>
97 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitcpu">RLimitCPU</a></li>
98 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitmem">RLimitMEM</a></li>
99 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitnproc">RLimitNPROC</a></li>
100 <li><img alt="" src="../images/down.gif" /> <a href="#scriptinterpretersource">ScriptInterpreterSource</a></li>
101 <li><img alt="" src="../images/down.gif" /> <a href="#seerequesttail">SeeRequestTail</a></li>
102 <li><img alt="" src="../images/down.gif" /> <a href="#serveradmin">ServerAdmin</a></li>
103 <li><img alt="" src="../images/down.gif" /> <a href="#serveralias">ServerAlias</a></li>
104 <li><img alt="" src="../images/down.gif" /> <a href="#servername">ServerName</a></li>
105 <li><img alt="" src="../images/down.gif" /> <a href="#serverpath">ServerPath</a></li>
106 <li><img alt="" src="../images/down.gif" /> <a href="#serverroot">ServerRoot</a></li>
107 <li><img alt="" src="../images/down.gif" /> <a href="#serversignature">ServerSignature</a></li>
108 <li><img alt="" src="../images/down.gif" /> <a href="#servertokens">ServerTokens</a></li>
109 <li><img alt="" src="../images/down.gif" /> <a href="#sethandler">SetHandler</a></li>
110 <li><img alt="" src="../images/down.gif" /> <a href="#setinputfilter">SetInputFilter</a></li>
111 <li><img alt="" src="../images/down.gif" /> <a href="#setoutputfilter">SetOutputFilter</a></li>
112 <li><img alt="" src="../images/down.gif" /> <a href="#timeout">TimeOut</a></li>
113 <li><img alt="" src="../images/down.gif" /> <a href="#traceenable">TraceEnable</a></li>
114 <li><img alt="" src="../images/down.gif" /> <a href="#undefine">UnDefine</a></li>
115 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalname">UseCanonicalName</a></li>
116 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></li>
117 <li><img alt="" src="../images/down.gif" /> <a href="#virtualhost"><VirtualHost></a></li>
119 <ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div>
121 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
122 <div class="directive-section"><h2><a name="AcceptFilter" id="AcceptFilter">AcceptFilter</a> <a name="acceptfilter" id="acceptfilter">Directive</a></h2>
123 <table class="directive">
124 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures optimizations for a Protocol's Listener Sockets</td></tr>
125 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptFilter <var>protocol</var> <var>accept_filter</var></code></td></tr>
126 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
127 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
128 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
129 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.1.5 and later.
130 On Windows from Apache httpd 2.3.3 and later.</td></tr>
132 <p>This directive enables operating system specific optimizations for a
133 listening socket by the <code class="directive">Protocol</code> type.
134 The basic premise is for the kernel to not send a socket to the server
135 process until either data is received or an entire HTTP Request is buffered.
136 Only <a href="http://www.freebsd.org/cgi/man.cgi?query=accept_filter&sektion=9">
137 FreeBSD's Accept Filters</a>, Linux's more primitive
138 <code>TCP_DEFER_ACCEPT</code>, and Windows' optimized AcceptEx()
139 are currently supported.</p>
141 <p>Using <code>none</code> for an argument will disable any accept filters
142 for that protocol. This is useful for protocols that require a server
143 send data first, such as <code>ftp:</code> or <code>nntp</code>:</p>
144 <pre class="prettyprint lang-config">
145 AcceptFilter nntp none
149 <p>The default protocol names are <code>https</code> for port 443
150 and <code>http</code> for all other ports. To specify another protocol
151 is being used with a listening port, add the <var>protocol</var>
152 argument to the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>
155 <p>The default values on FreeBSD are:</p>
156 <pre class="prettyprint lang-config">
157 AcceptFilter http httpready
158 AcceptFilter https dataready
162 <p>The <code>httpready</code> accept filter buffers entire HTTP requests at
163 the kernel level. Once an entire request is received, the kernel then
164 sends it to the server. See the
165 <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_http&sektion=9">
166 accf_http(9)</a> man page for more details. Since HTTPS requests are
167 encrypted only the <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_data&sektion=9">
168 accf_data(9)</a> filter is used.</p>
170 <p>The default values on Linux are:</p>
171 <pre class="prettyprint lang-config">
172 AcceptFilter http data
173 AcceptFilter https data
177 <p>Linux's <code>TCP_DEFER_ACCEPT</code> does not support buffering http
178 requests. Any value besides <code>none</code> will enable
179 <code>TCP_DEFER_ACCEPT</code> on that listener. For more details
181 <a href="http://homepages.cwi.nl/~aeb/linux/man2html/man7/tcp.7.html">
182 tcp(7)</a> man page.</p>
184 <p>The default values on Windows are:</p>
185 <pre class="prettyprint lang-config">
186 AcceptFilter http data
187 AcceptFilter https data
191 <p>Window's mpm_winnt interprets the AcceptFilter to toggle the AcceptEx()
192 API, and does not support http protocol buffering. There are two values
193 which utilize the Windows AcceptEx() API and will recycle network
194 sockets between connections. <code>data</code> waits until data has
195 been transmitted as documented above, and the initial data buffer and
196 network endpoint addresses are all retrieved from the single AcceptEx()
197 invocation. <code>connect</code> will use the AcceptEx() API, also
198 retrieve the network endpoint addresses, but like <code>none</code>
199 the <code>connect</code> option does not wait for the initial data
202 <p>On Windows, <code>none</code> uses accept() rather than AcceptEx()
203 and will not recycle sockets between connections. This is useful for
204 network adapters with broken driver support, as well as some virtual
205 network providers such as vpn drivers, or spam, virus or spyware
211 <li><code class="directive"><a href="#protocol">Protocol</a></code></li>
214 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
215 <div class="directive-section"><h2><a name="AcceptPathInfo" id="AcceptPathInfo">AcceptPathInfo</a> <a name="acceptpathinfo" id="acceptpathinfo">Directive</a></h2>
216 <table class="directive">
217 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Resources accept trailing pathname information</td></tr>
218 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptPathInfo On|Off|Default</code></td></tr>
219 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AcceptPathInfo Default</code></td></tr>
220 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
221 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
222 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
223 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
224 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.0.30 and later</td></tr>
227 <p>This directive controls whether requests that contain trailing
228 pathname information that follows an actual filename (or
229 non-existent file in an existing directory) will be accepted or
230 rejected. The trailing pathname information can be made
231 available to scripts in the <code>PATH_INFO</code> environment
234 <p>For example, assume the location <code>/test/</code> points to
235 a directory that contains only the single file
236 <code>here.html</code>. Then requests for
237 <code>/test/here.html/more</code> and
238 <code>/test/nothere.html/more</code> both collect
239 <code>/more</code> as <code>PATH_INFO</code>.</p>
241 <p>The three possible arguments for the
242 <code class="directive">AcceptPathInfo</code> directive are:</p>
244 <dt><code>Off</code></dt><dd>A request will only be accepted if it
245 maps to a literal path that exists. Therefore a request with
246 trailing pathname information after the true filename such as
247 <code>/test/here.html/more</code> in the above example will return
248 a 404 NOT FOUND error.</dd>
250 <dt><code>On</code></dt><dd>A request will be accepted if a
251 leading path component maps to a file that exists. The above
252 example <code>/test/here.html/more</code> will be accepted if
253 <code>/test/here.html</code> maps to a valid file.</dd>
255 <dt><code>Default</code></dt><dd>The treatment of requests with
256 trailing pathname information is determined by the <a href="../handler.html">handler</a> responsible for the request.
257 The core handler for normal files defaults to rejecting
258 <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
259 <code>PATH_INFO</code> by default.</dd>
262 <p>The primary purpose of the <code>AcceptPathInfo</code>
263 directive is to allow you to override the handler's choice of
264 accepting or rejecting <code>PATH_INFO</code>. This override is required,
265 for example, when you use a <a href="../filter.html">filter</a>, such
266 as <a href="mod_include.html">INCLUDES</a>, to generate content
267 based on <code>PATH_INFO</code>. The core handler would usually reject
268 the request, so you can use the following configuration to enable
271 <pre class="prettyprint lang-config">
272 <Files "mypaths.shtml">
274 SetOutputFilter INCLUDES
282 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
283 <div class="directive-section"><h2><a name="AccessFileName" id="AccessFileName">AccessFileName</a> <a name="accessfilename" id="accessfilename">Directive</a></h2>
284 <table class="directive">
285 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Name of the distributed configuration file</td></tr>
286 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AccessFileName <var>filename</var> [<var>filename</var>] ...</code></td></tr>
287 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AccessFileName .htaccess</code></td></tr>
288 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
289 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
290 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
292 <p>While processing a request the server looks for
293 the first existing configuration file from this list of names in
294 every directory of the path to the document, if distributed
295 configuration files are <a href="#allowoverride">enabled for that
296 directory</a>. For example:</p>
298 <pre class="prettyprint lang-config">AccessFileName .acl</pre>
301 <p>before returning the document
302 <code>/usr/local/web/index.html</code>, the server will read
303 <code>/.acl</code>, <code>/usr/.acl</code>,
304 <code>/usr/local/.acl</code> and <code>/usr/local/web/.acl</code>
305 for directives, unless they have been disabled with</p>
307 <pre class="prettyprint lang-config">
316 <li><code class="directive"><a href="#allowoverride">AllowOverride</a></code></li>
317 <li><a href="../configuring.html">Configuration Files</a></li>
318 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
321 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
322 <div class="directive-section"><h2><a name="AddDefaultCharset" id="AddDefaultCharset">AddDefaultCharset</a> <a name="adddefaultcharset" id="adddefaultcharset">Directive</a></h2>
323 <table class="directive">
324 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Default charset parameter to be added when a response
325 content-type is <code>text/plain</code> or <code>text/html</code></td></tr>
326 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AddDefaultCharset On|Off|<var>charset</var></code></td></tr>
327 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AddDefaultCharset Off</code></td></tr>
328 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
329 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
330 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
331 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
333 <p>This directive specifies a default value for the media type
334 charset parameter (the name of a character encoding) to be added
335 to a response if and only if the response's content-type is either
336 <code>text/plain</code> or <code>text/html</code>. This should override
337 any charset specified in the body of the response via a <code>META</code>
338 element, though the exact behavior is often dependent on the user's client
339 configuration. A setting of <code>AddDefaultCharset Off</code>
340 disables this functionality. <code>AddDefaultCharset On</code> enables
341 a default charset of <code>iso-8859-1</code>. Any other value is assumed
342 to be the <var>charset</var> to be used, which should be one of the
343 <a href="http://www.iana.org/assignments/character-sets">IANA registered
344 charset values</a> for use in Internet media types (MIME types).
347 <pre class="prettyprint lang-config">AddDefaultCharset utf-8</pre>
350 <p><code class="directive">AddDefaultCharset</code> should only be used when all
351 of the text resources to which it applies are known to be in that
352 character encoding and it is too inconvenient to label their charset
353 individually. One such example is to add the charset parameter
354 to resources containing generated content, such as legacy CGI
355 scripts, that might be vulnerable to cross-site scripting attacks
356 due to user-provided data being included in the output. Note, however,
357 that a better solution is to just fix (or delete) those scripts, since
358 setting a default charset does not protect users that have enabled
359 the "auto-detect character encoding" feature on their browser.</p>
363 <li><code class="directive"><a href="../mod/mod_mime.html#addcharset">AddCharset</a></code></li>
366 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
367 <div class="directive-section"><h2><a name="AllowEncodedSlashes" id="AllowEncodedSlashes">AllowEncodedSlashes</a> <a name="allowencodedslashes" id="allowencodedslashes">Directive</a></h2>
368 <table class="directive">
369 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines whether encoded path separators in URLs are allowed to
370 be passed through</td></tr>
371 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowEncodedSlashes On|Off|NoDecode</code></td></tr>
372 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowEncodedSlashes Off</code></td></tr>
373 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
374 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
375 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
376 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.0.46 and later.
377 NoDecode option available in 2.3.12 and later.</td></tr>
379 <p>The <code class="directive">AllowEncodedSlashes</code> directive allows URLs
380 which contain encoded path separators (<code>%2F</code> for <code>/</code>
381 and additionally <code>%5C</code> for <code>\</code> on according systems)
382 to be used in the path info.</p>
384 <p>With the default value, <code>Off</code>, such URLs are refused
385 with a 404 (Not found) error.</p>
387 <p>With the value <code>On</code>, such URLs are accepted, and encoded
388 slashes are decoded like all other encoded characters.</p>
390 <p>With the value <code>NoDecode</code>, such URLs are accepted, but
391 encoded slashes are not decoded but left in their encoded state.</p>
393 <p>Turning <code class="directive">AllowEncodedSlashes</code> <code>On</code> is
394 mostly useful when used in conjunction with <code>PATH_INFO</code>.</p>
396 <div class="note"><h3>Note</h3>
397 <p>If encoded slashes are needed in path info, use of <code>NoDecode</code> is
398 strongly recommended as a security measure. Allowing slashes
399 to be decoded could potentially allow unsafe paths.</p>
404 <li><code class="directive"><a href="#acceptpathinfo">AcceptPathInfo</a></code></li>
407 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
408 <div class="directive-section"><h2><a name="AllowOverride" id="AllowOverride">AllowOverride</a> <a name="allowoverride" id="allowoverride">Directive</a></h2>
409 <table class="directive">
410 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Types of directives that are allowed in
411 <code>.htaccess</code> files</td></tr>
412 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowOverride All|None|<var>directive-type</var>
413 [<var>directive-type</var>] ...</code></td></tr>
414 <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>
415 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
416 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
417 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
419 <p>When the server finds an <code>.htaccess</code> file (as
420 specified by <code class="directive"><a href="#accessfilename">AccessFileName</a></code>)
421 it needs to know which directives declared in that file can override
422 earlier configuration directives.</p>
424 <div class="note"><h3>Only available in <Directory> sections</h3>
425 <code class="directive">AllowOverride</code> is valid only in
426 <code class="directive"><a href="#directory"><Directory></a></code>
427 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
428 <code class="directive"><a href="#files"><Files></a></code> sections.
431 <p>When this directive is set to <code>None</code> and <code class="directive"><a href="#allowoverridelist">AllowOverrideList</a></code> is set to
432 <code>None</code> <a href="#accessfilename">.htaccess</a> files are
433 completely ignored. In this case, the server will not even attempt
434 to read <code>.htaccess</code> files in the filesystem.</p>
436 <p>When this directive is set to <code>All</code>, then any
437 directive which has the .htaccess <a href="directive-dict.html#Context">Context</a> is allowed in
438 <code>.htaccess</code> files.</p>
440 <p>The <var>directive-type</var> can be one of the following
441 groupings of directives.</p>
448 Allow use of the authorization directives (<code class="directive"><a href="../mod/mod_authz_dbm.html#authdbmgroupfile">AuthDBMGroupFile</a></code>,
449 <code class="directive"><a href="../mod/mod_authn_dbm.html#authdbmuserfile">AuthDBMUserFile</a></code>,
450 <code class="directive"><a href="../mod/mod_authz_groupfile.html#authgroupfile">AuthGroupFile</a></code>,
451 <code class="directive"><a href="../mod/mod_authn_core.html#authname">AuthName</a></code>,
452 <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>
457 Allow use of the directives controlling document types
458 (<code class="directive"><a href="#errordocument">ErrorDocument</a></code>,
459 <code class="directive"><a href="#forcetype">ForceType</a></code>,
460 <code class="directive"><a href="../mod/mod_negotiation.html#languagepriority">LanguagePriority</a></code>,
461 <code class="directive"><a href="#sethandler">SetHandler</a></code>,
462 <code class="directive"><a href="#setinputfilter">SetInputFilter</a></code>,
463 <code class="directive"><a href="#setoutputfilter">SetOutputFilter</a></code>, and
464 <code class="module"><a href="../mod/mod_mime.html">mod_mime</a></code> Add* and Remove* directives),
465 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>),
466 <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>),
467 <code class="module"><a href="../mod/mod_alias.html">mod_alias</a></code> directives (<code class="directive"><a href="../mod/mod_alias.html#redirect">Redirect</a></code>, <code class="directive"><a href="../mod/mod_alias.html#redirecttemp">RedirectTemp</a></code>, <code class="directive"><a href="../mod/mod_alias.html#redirectpermanent">RedirectPermanent</a></code>, <code class="directive"><a href="../mod/mod_alias.html#redirectmatch">RedirectMatch</a></code>), and
468 <code class="directive"><a href="../mod/mod_actions.html#action">Action</a></code> from
469 <code class="module"><a href="../mod/mod_actions.html">mod_actions</a></code>.
475 Allow use of the directives controlling directory indexing
476 (<code class="directive"><a href="../mod/mod_autoindex.html#adddescription">AddDescription</a></code>,
477 <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>,
478 <code class="directive"><a href="../mod/mod_autoindex.html#addiconbytype">AddIconByType</a></code>,
479 <code class="directive"><a href="../mod/mod_autoindex.html#defaulticon">DefaultIcon</a></code>, <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>, , <code class="directive"><a href="../mod/mod_dir.html#fallbackresource">FallbackResource</a></code>,<a href="mod_autoindex.html#indexoptions.fancyindexing"><code>FancyIndexing</code></a>, <code class="directive"><a href="../mod/mod_autoindex.html#headername">HeaderName</a></code>, <code class="directive"><a href="../mod/mod_autoindex.html#indexignore">IndexIgnore</a></code>, <code class="directive"><a href="../mod/mod_autoindex.html#indexoptions">IndexOptions</a></code>, <code class="directive"><a href="../mod/mod_autoindex.html#readmename">ReadmeName</a></code>,
485 Allow use of the directives controlling host access (<code class="directive"><a href="../mod/mod_access_compat.html#allow">Allow</a></code>, <code class="directive"><a href="../mod/mod_access_compat.html#deny">Deny</a></code> and <code class="directive"><a href="../mod/mod_access_compat.html#order">Order</a></code>).</dd>
490 <dt>Nonfatal=[Override|Unknown|All]</dt>
493 Allow use of AllowOverride option to treat syntax errors in
494 .htaccess as non-fatal: instead of causing an Internal Server
495 Error, disallowed or unrecognised directives will be ignored
496 and a warning logged:
498 <li><strong>Nonfatal=Override</strong> treats directives
499 forbidden by AllowOverride as non-fatal.</li>
500 <li><strong>Nonfatal=Unknown</strong> treats unknown directives
501 as non-fatal. This covers typos and directives implemented
502 by a module that's not present.</li>
503 <li><strong>Nonfatal=All</strong> treats both the above as non-fatal.</li>
505 <p>Note that a syntax error in a valid directive will still cause
506 an internal server error.</p>
507 <div class="warning"><h3>Security</h3>
508 Nonfatal errors may have security implications for .htaccess users.
509 For example, if AllowOverride disallows AuthConfig, users'
510 configuration designed to restrict access to a site will be disabled.
514 <dt>Options[=<var>Option</var>,...]</dt>
517 Allow use of the directives controlling specific directory
518 features (<code class="directive"><a href="#options">Options</a></code> and
519 <code class="directive"><a href="../mod/mod_include.html#xbithack">XBitHack</a></code>).
520 An equal sign may be given followed by a comma (but no spaces)
521 separated lists of options that may be set using the <code class="directive"><a href="#options">Options</a></code> command.
523 <div class="note"><h3>Implicit disabling of Options</h3>
524 <p>Even though the list of options that may be used in .htaccess files
525 can be limited with this directive, as long as any <code class="directive"><a href="#options">Options</a></code> directive is allowed any
526 other inherited option can be disabled by using the non-relative
527 syntax. In other words, this mechanism cannot force a specific option
528 to remain <em>set</em> while allowing any others to be set.
531 <div class="example"><p><code>
532 AllowOverride Options=Indexes,MultiViews
539 <pre class="prettyprint lang-config">AllowOverride AuthConfig Indexes</pre>
542 <p>In the example above all directives that are neither in the group
543 <code>AuthConfig</code> nor <code>Indexes</code> cause an internal
546 <div class="note"><p>For security and performance reasons, do not set
547 <code>AllowOverride</code> to anything other than <code>None</code>
548 in your <code><Directory /></code> block. Instead, find (or
549 create) the <code><Directory></code> block that refers to the
550 directory where you're actually planning to place a
551 <code>.htaccess</code> file.</p>
556 <li><code class="directive"><a href="#accessfilename">AccessFileName</a></code></li>
557 <li><code class="directive"><a href="#allowoverridelist">AllowOverrideList</a></code></li>
558 <li><a href="../configuring.html">Configuration Files</a></li>
559 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
562 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
563 <div class="directive-section"><h2><a name="AllowOverrideList" id="AllowOverrideList">AllowOverrideList</a> <a name="allowoverridelist" id="allowoverridelist">Directive</a></h2>
564 <table class="directive">
565 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Individual directives that are allowed in
566 <code>.htaccess</code> files</td></tr>
567 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowOverrideList None|<var>directive</var>
568 [<var>directive-type</var>] ...</code></td></tr>
569 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowOverrideList None</code></td></tr>
570 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
571 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
572 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
574 <p>When the server finds an <code>.htaccess</code> file (as
575 specified by <code class="directive"><a href="#accessfilename">AccessFileName</a></code>)
576 it needs to know which directives declared in that file can override
577 earlier configuration directives.</p>
579 <div class="note"><h3>Only available in <Directory> sections</h3>
580 <code class="directive">AllowOverrideList</code> is valid only in
581 <code class="directive"><a href="#directory"><Directory></a></code>
582 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
583 <code class="directive"><a href="#files"><Files></a></code> sections.
586 <p>When this directive is set to <code>None</code> and <code class="directive"><a href="#allowoverride">AllowOverride</a></code> is set to <code>None</code>,
587 then <a href="#accessfilename">.htaccess</a> files are completely
588 ignored. In this case, the server will not even attempt to read
589 <code>.htaccess</code> files in the filesystem.</p>
593 <pre class="prettyprint lang-config">
595 AllowOverrideList Redirect RedirectMatch
599 <p>In the example above only the <code>Redirect</code> and
600 <code>RedirectMatch</code> directives are allowed. All others will
601 cause an internal server error.</p>
605 <pre class="prettyprint lang-config">
606 AllowOverride AuthConfig
607 AllowOverrideList CookieTracking CookieName
611 <p>In the example above <code class="directive"><a href="#allowoverride ">AllowOverride
612 </a></code> grants permission to the <code>AuthConfig</code>
613 directive grouping and <code class="directive">AllowOverrideList</code> grants
614 permission to only two directives from the <code>FileInfo</code> directive
615 grouping. All others will cause an internal server error.</p>
619 <li><code class="directive"><a href="#accessfilename">AccessFileName</a></code></li>
620 <li><code class="directive"><a href="#allowoverride">AllowOverride</a></code></li>
621 <li><a href="../configuring.html">Configuration Files</a></li>
622 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
625 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
626 <div class="directive-section"><h2><a name="CGIMapExtension" id="CGIMapExtension">CGIMapExtension</a> <a name="cgimapextension" id="cgimapextension">Directive</a></h2>
627 <table class="directive">
628 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
630 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CGIMapExtension <var>cgi-path</var> <var>.extension</var></code></td></tr>
631 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
632 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
633 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
634 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
635 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>NetWare only</td></tr>
637 <p>This directive is used to control how Apache httpd finds the
638 interpreter used to run CGI scripts. For example, setting
639 <code>CGIMapExtension sys:\foo.nlm .foo</code> will
640 cause all CGI script files with a <code>.foo</code> extension to
641 be passed to the FOO interpreter.</p>
644 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
645 <div class="directive-section"><h2><a name="ContentDigest" id="ContentDigest">ContentDigest</a> <a name="contentdigest" id="contentdigest">Directive</a></h2>
646 <table class="directive">
647 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables the generation of <code>Content-MD5</code> HTTP Response
649 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ContentDigest On|Off</code></td></tr>
650 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ContentDigest Off</code></td></tr>
651 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
652 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
653 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
654 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
656 <p>This directive enables the generation of
657 <code>Content-MD5</code> headers as defined in RFC1864
658 respectively RFC2616.</p>
660 <p>MD5 is an algorithm for computing a "message digest"
661 (sometimes called "fingerprint") of arbitrary-length data, with
662 a high degree of confidence that any alterations in the data
663 will be reflected in alterations in the message digest.</p>
665 <p>The <code>Content-MD5</code> header provides an end-to-end
666 message integrity check (MIC) of the entity-body. A proxy or
667 client may check this header for detecting accidental
668 modification of the entity-body in transit. Example header:</p>
670 <div class="example"><p><code>
671 Content-MD5: AuLb7Dp1rqtRtxz2m9kRpA==
674 <p>Note that this can cause performance problems on your server
675 since the message digest is computed on every request (the
676 values are not cached).</p>
678 <p><code>Content-MD5</code> is only sent for documents served
679 by the <code class="module"><a href="../mod/core.html">core</a></code>, and not by any module. For example,
680 SSI documents, output from CGI scripts, and byte range responses
681 do not have this header.</p>
684 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
685 <div class="directive-section"><h2><a name="DefaultRuntimeDir" id="DefaultRuntimeDir">DefaultRuntimeDir</a> <a name="defaultruntimedir" id="defaultruntimedir">Directive</a></h2>
686 <table class="directive">
687 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server run-time files</td></tr>
688 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultRuntimeDir <var>directory-path</var></code></td></tr>
689 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultRuntimeDir DEFAULT_REL_RUNTIMEDIR (logs/)</code></td></tr>
690 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
691 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
692 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
694 <p>The <code class="directive">DefaultRuntimeDir</code> directive sets the
695 directory in which the server will create various run-time files
696 (shared memory, locks, etc.). If set as a relative path, the full path
697 will be relative to <code class="directive">ServerRoot</code>.</p>
699 <p><strong>Example</strong></p>
700 <pre class="prettyprint lang-config">
701 DefaultRuntimeDir scratch/
705 <p>The default location of <code class="directive">DefaultRuntimeDir</code> may be
706 modified by changing the <code>DEFAULT_REL_RUNTIMEDIR</code> #define
709 <p>Note: <code class="directive">ServerRoot</code> should be specified before this
710 directive is used, otherwise the default value of <code class="directive">ServerRoot</code>
711 would be used to set the base directory.</p>
716 <li><a href="../misc/security_tips.html#serverroot">the
717 security tips</a> for information on how to properly set
718 permissions on the <code class="directive">ServerRoot</code></li>
721 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
722 <div class="directive-section"><h2><a name="DefaultType" id="DefaultType">DefaultType</a> <a name="defaulttype" id="defaulttype">Directive</a></h2>
723 <table class="directive">
724 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>This directive has no effect other than to emit warnings
725 if the value is not <code>none</code>. In prior versions, DefaultType
726 would specify a default media type to assign to response content for
727 which no other media type configuration could be found.
729 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultType <var>media-type|none</var></code></td></tr>
730 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultType none</code></td></tr>
731 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
732 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
733 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
734 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
735 <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>
737 <p>This directive has been disabled. For backwards compatibility
738 of configuration files, it may be specified with the value
739 <code>none</code>, meaning no default media type. For example:</p>
741 <pre class="prettyprint lang-config">DefaultType None</pre>
744 <p><code>DefaultType None</code> is only available in
745 httpd-2.2.7 and later.</p>
747 <p>Use the mime.types configuration file and the
748 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code> to configure media
749 type assignments via file extensions, or the
750 <code class="directive"><a href="#forcetype">ForceType</a></code> directive to configure
751 the media type for specific resources. Otherwise, the server will
752 send the response without a Content-Type header field and the
753 recipient may attempt to guess the media type.</p>
756 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
757 <div class="directive-section"><h2><a name="Define" id="Define">Define</a> <a name="define" id="define">Directive</a></h2>
758 <table class="directive">
759 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Define a variable</td></tr>
760 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Define <var>parameter-name</var> [<var>parameter-value</var>]</code></td></tr>
761 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
762 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
763 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
765 <p>In its one parameter form, <code class="directive">Define</code> is equivalent
766 to passing the <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>. It
767 can be used to toggle the use of
768 <code class="directive"><a href="#ifdefine"><IfDefine></a></code> sections
769 without needing to alter <code>-D</code> arguments in any startup
772 <p>In addition to that, if the second parameter is given, a config variable
773 is set to this value. The variable can be used in the configuration using
774 the <code>${VAR}</code> syntax. The variable is always globally defined
775 and not limited to the scope of the surrounding config section.</p>
777 <pre class="prettyprint lang-config">
778 <IfDefine TEST>
779 Define servername test.example.com
781 <IfDefine !TEST>
782 Define servername www.example.com
786 DocumentRoot /var/www/${servername}/htdocs
790 <p>Variable names may not contain colon ":" characters, to avoid clashes
791 with <code class="directive"><a href="../mod/mod_rewrite.html#rewritemap">RewriteMap</a></code>'s syntax.</p>
794 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
795 <div class="directive-section"><h2><a name="Directory" id="Directory"><Directory></a> <a name="directory" id="directory">Directive</a></h2>
796 <table class="directive">
797 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose a group of directives that apply only to the
798 named file-system directory, sub-directories, and their contents.</td></tr>
799 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Directory <var>directory-path</var>>
800 ... </Directory></code></td></tr>
801 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
802 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
803 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
805 <p><code class="directive"><Directory></code> and
806 <code></Directory></code> are used to enclose a group of
807 directives that will apply only to the named directory,
808 sub-directories of that directory, and the files within the respective
809 directories. Any directive that is allowed
810 in a directory context may be used. <var>Directory-path</var> is
811 either the full path to a directory, or a wild-card string using
812 Unix shell-style matching. In a wild-card string, <code>?</code> matches
813 any single character, and <code>*</code> matches any sequences of
814 characters. You may also use <code>[]</code> character ranges. None
815 of the wildcards match a `/' character, so <code><Directory
816 /*/public_html></code> will not match
817 <code>/home/user/public_html</code>, but <code><Directory
818 /home/*/public_html></code> will match. Example:</p>
820 <pre class="prettyprint lang-config">
821 <Directory "/usr/local/httpd/htdocs">
822 Options Indexes FollowSymLinks
828 <p>Be careful with the <var>directory-path</var> arguments:
829 They have to literally match the filesystem path which Apache httpd uses
830 to access the files. Directives applied to a particular
831 <code><Directory></code> will not apply to files accessed from
832 that same directory via a different path, such as via different symbolic
836 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular
837 expressions</a> can also be used, with the addition of the
838 <code>~</code> character. For example:</p>
840 <pre class="prettyprint lang-config">
841 <Directory ~ "^/www/[0-9]{3}">
847 <p>would match directories in <code>/www/</code> that consisted of
850 <p>If multiple (non-regular expression) <code class="directive"><Directory></code> sections
851 match the directory (or one of its parents) containing a document,
852 then the directives are applied in the order of shortest match
853 first, interspersed with the directives from the <a href="#accessfilename">.htaccess</a> files. For example,
856 <pre class="prettyprint lang-config">
861 <Directory "/home">
862 AllowOverride FileInfo
867 <p>for access to the document <code>/home/web/dir/doc.html</code>
871 <li>Apply directive <code>AllowOverride None</code>
872 (disabling <code>.htaccess</code> files).</li>
874 <li>Apply directive <code>AllowOverride FileInfo</code> (for
875 directory <code>/home</code>).</li>
877 <li>Apply any <code>FileInfo</code> directives in
878 <code>/home/.htaccess</code>, <code>/home/web/.htaccess</code> and
879 <code>/home/web/dir/.htaccess</code> in that order.</li>
882 <p>Regular expressions are not considered until after all of the
883 normal sections have been applied. Then all of the regular
884 expressions are tested in the order they appeared in the
885 configuration file. For example, with</p>
887 <pre class="prettyprint lang-config">
888 <Directory ~ "abc$">
889 # ... directives here ...
894 <p>the regular expression section won't be considered until after
895 all normal <code class="directive"><Directory></code>s and
896 <code>.htaccess</code> files have been applied. Then the regular
897 expression will match on <code>/home/abc/public_html/abc</code> and
898 the corresponding <code class="directive"><Directory></code> will
901 <p><strong>Note that the default access for
902 <code><Directory /></code> is to permit all access.
903 This means that Apache httpd will serve any file mapped from an URL. It is
904 recommended that you change this with a block such
907 <pre class="prettyprint lang-config">
914 <p><strong>and then override this for directories you
915 <em>want</em> accessible. See the <a href="../misc/security_tips.html">Security Tips</a> page for more
916 details.</strong></p>
918 <p>The directory sections occur in the <code>httpd.conf</code> file.
919 <code class="directive"><Directory></code> directives
920 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>
924 <li><a href="../sections.html">How <Directory>,
925 <Location> and <Files> sections work</a> for an
926 explanation of how these different sections are combined when a
927 request is received</li>
930 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
931 <div class="directive-section"><h2><a name="DirectoryMatch" id="DirectoryMatch"><DirectoryMatch></a> <a name="directorymatch" id="directorymatch">Directive</a></h2>
932 <table class="directive">
933 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose directives that apply to
934 the contents of file-system directories matching a regular expression.</td></tr>
935 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><DirectoryMatch <var>regex</var>>
936 ... </DirectoryMatch></code></td></tr>
937 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
938 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
939 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
941 <p><code class="directive"><DirectoryMatch></code> and
942 <code></DirectoryMatch></code> are used to enclose a group
943 of directives which will apply only to the named directory (and the files within),
944 the same as <code class="directive"><a href="#directory"><Directory></a></code>.
945 However, it takes as an argument a
946 <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>. For example:</p>
948 <pre class="prettyprint lang-config">
949 <DirectoryMatch "^/www/(.+/)?[0-9]{3}">
951 </DirectoryMatch>
955 <p>would match directories in <code>/www/</code> that consisted of three
958 <div class="note"><h3>Compatability</h3>
959 Prior to 2.3.9, this directive implicitly applied to sub-directories
960 (like <code class="directive"><a href="#directory"><Directory></a></code>) and
961 could not match the end of line symbol ($). In 2.3.9 and later,
962 only directories that match the expression are affected by the enclosed
966 <div class="note"><h3>Trailing Slash</h3>
967 This directive applies to requests for directories that may or may
968 not end in a trailing slash, so expressions that are anchored to the
969 end of line ($) must be written with care.
974 <li><code class="directive"><a href="#directory"><Directory></a></code> for
975 a description of how regular expressions are mixed in with normal
976 <code class="directive"><Directory></code>s</li>
977 <li><a href="../sections.html">How <Directory>, <Location> and
978 <Files> sections work</a> for an explanation of how these different
979 sections are combined when a request is received</li>
982 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
983 <div class="directive-section"><h2><a name="DocumentRoot" id="DocumentRoot">DocumentRoot</a> <a name="documentroot" id="documentroot">Directive</a></h2>
984 <table class="directive">
985 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory that forms the main document tree visible
986 from the web</td></tr>
987 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DocumentRoot <var>directory-path</var></code></td></tr>
988 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DocumentRoot /usr/local/apache/htdocs</code></td></tr>
989 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
990 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
991 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
993 <p>This directive sets the directory from which <code class="program"><a href="../programs/httpd.html">httpd</a></code>
994 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
995 path from the requested URL to the document root to make the
996 path to the document. Example:</p>
998 <pre class="prettyprint lang-config">DocumentRoot "/usr/web"</pre>
1001 <p>then an access to
1002 <code>http://my.example.com/index.html</code> refers to
1003 <code>/usr/web/index.html</code>. If the <var>directory-path</var> is
1004 not absolute then it is assumed to be relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1006 <p>The <code class="directive">DocumentRoot</code> should be specified without
1007 a trailing slash.</p>
1011 <li><a href="../urlmapping.html#documentroot">Mapping URLs to Filesystem
1015 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1016 <div class="directive-section"><h2><a name="Else" id="Else"><Else></a> <a name="else" id="else">Directive</a></h2>
1017 <table class="directive">
1018 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if the condition of a
1019 previous <code class="directive"><a href="#if"><If></a></code> or
1020 <code class="directive"><a href="#elseif"><ElseIf></a></code> section is not
1021 satisfied by a request at runtime</td></tr>
1022 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Else> ... </Else></code></td></tr>
1023 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1024 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1025 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1026 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1028 <p>The <code class="directive"><Else></code> applies the enclosed
1029 directives if and only if the most recent
1030 <code class="directive"><If></code> or
1031 <code class="directive"><ElseIf></code> section
1032 in the same scope has not been applied.
1033 For example: In </p>
1035 <pre class="prettyprint lang-config">
1036 <If "-z req('Host')">
1045 <p> The <code class="directive"><If></code> would match HTTP/1.0
1046 requests without a <var>Host:</var> header and the
1047 <code class="directive"><Else></code> would match requests
1048 with a <var>Host:</var> header.</p>
1053 <li><code class="directive"><a href="#if"><If></a></code></li>
1054 <li><code class="directive"><a href="#elseif"><ElseIf></a></code></li>
1055 <li><a href="../sections.html">How <Directory>, <Location>,
1056 <Files> sections work</a> for an explanation of how these
1057 different sections are combined when a request is received.
1058 <code class="directive"><If></code>,
1059 <code class="directive"><ElseIf></code>, and
1060 <code class="directive"><Else></code> are applied last.</li>
1063 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1064 <div class="directive-section"><h2><a name="ElseIf" id="ElseIf"><ElseIf></a> <a name="elseif" id="elseif">Directive</a></h2>
1065 <table class="directive">
1066 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is satisfied
1067 by a request at runtime while the condition of a previous
1068 <code class="directive"><a href="#if"><If></a></code> or
1069 <code class="directive"><ElseIf></code> section is not
1071 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><ElseIf <var>expression</var>> ... </ElseIf></code></td></tr>
1072 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1073 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1074 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1075 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1077 <p>The <code class="directive"><ElseIf></code> applies the enclosed
1078 directives if and only if both the given condition evaluates to true and
1079 the most recent <code class="directive"><If></code> or
1080 <code class="directive"><ElseIf></code> section in the same scope has
1081 not been applied. For example: In </p>
1083 <pre class="prettyprint lang-config">
1084 <If "-R '10.1.0.0/16'">
1087 <ElseIf "-R '10.0.0.0/8'">
1096 <p>The <code class="directive"><ElseIf></code> would match if
1097 the remote address of a request belongs to the subnet 10.0.0.0/8 but
1098 not to the subnet 10.1.0.0/16.</p>
1103 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
1104 for a complete reference and more examples.</li>
1105 <li><code class="directive"><a href="#if"><If></a></code></li>
1106 <li><code class="directive"><a href="#else"><Else></a></code></li>
1107 <li><a href="../sections.html">How <Directory>, <Location>,
1108 <Files> sections work</a> for an explanation of how these
1109 different sections are combined when a request is received.
1110 <code class="directive"><If></code>,
1111 <code class="directive"><ElseIf></code>, and
1112 <code class="directive"><Else></code> are applied last.</li>
1115 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1116 <div class="directive-section"><h2><a name="EnableMMAP" id="EnableMMAP">EnableMMAP</a> <a name="enablemmap" id="enablemmap">Directive</a></h2>
1117 <table class="directive">
1118 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use memory-mapping to read files during delivery</td></tr>
1119 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableMMAP On|Off</code></td></tr>
1120 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableMMAP On</code></td></tr>
1121 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1122 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1123 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1124 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1126 <p>This directive controls whether the <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use
1127 memory-mapping if it needs to read the contents of a file during
1128 delivery. By default, when the handling of a request requires
1129 access to the data within a file -- for example, when delivering a
1130 server-parsed file using <code class="module"><a href="../mod/mod_include.html">mod_include</a></code> -- Apache httpd
1131 memory-maps the file if the OS supports it.</p>
1133 <p>This memory-mapping sometimes yields a performance improvement.
1134 But in some environments, it is better to disable the memory-mapping
1135 to prevent operational problems:</p>
1138 <li>On some multiprocessor systems, memory-mapping can reduce the
1139 performance of the <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</li>
1140 <li>Deleting or truncating a file while <code class="program"><a href="../programs/httpd.html">httpd</a></code>
1141 has it memory-mapped can cause <code class="program"><a href="../programs/httpd.html">httpd</a></code> to
1142 crash with a segmentation fault.
1146 <p>For server configurations that are vulnerable to these problems,
1147 you should disable memory-mapping of delivered files by specifying:</p>
1149 <pre class="prettyprint lang-config">EnableMMAP Off</pre>
1152 <p>For NFS mounted files, this feature may be disabled explicitly for
1153 the offending files by specifying:</p>
1155 <pre class="prettyprint lang-config">
1156 <Directory "/path-to-nfs-files">
1163 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1164 <div class="directive-section"><h2><a name="EnableSendfile" id="EnableSendfile">EnableSendfile</a> <a name="enablesendfile" id="enablesendfile">Directive</a></h2>
1165 <table class="directive">
1166 <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>
1167 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableSendfile On|Off</code></td></tr>
1168 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableSendfile Off</code></td></tr>
1169 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1170 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1171 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1172 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1173 <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
1174 version 2.3.9.</td></tr>
1176 <p>This directive controls whether <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use the
1177 sendfile support from the kernel to transmit file contents to the client.
1178 By default, when the handling of a request requires no access
1179 to the data within a file -- for example, when delivering a
1180 static file -- Apache httpd uses sendfile to deliver the file contents
1181 without ever reading the file if the OS supports it.</p>
1183 <p>This sendfile mechanism avoids separate read and send operations,
1184 and buffer allocations. But on some platforms or within some
1185 filesystems, it is better to disable this feature to avoid
1186 operational problems:</p>
1189 <li>Some platforms may have broken sendfile support that the build
1190 system did not detect, especially if the binaries were built on
1191 another box and moved to such a machine with broken sendfile
1193 <li>On Linux the use of sendfile triggers TCP-checksum
1194 offloading bugs on certain networking cards when using IPv6.</li>
1195 <li>On Linux on Itanium, <code>sendfile</code> may be unable to handle
1196 files over 2GB in size.</li>
1197 <li>With a network-mounted <code class="directive"><a href="#documentroot">DocumentRoot</a></code> (e.g., NFS, SMB, CIFS, FUSE),
1198 the kernel may be unable to serve the network file through
1202 <p>For server configurations that are not vulnerable to these problems,
1203 you may enable this feature by specifying:</p>
1205 <pre class="prettyprint lang-config">EnableSendfile On</pre>
1208 <p>For network mounted files, this feature may be disabled explicitly
1209 for the offending files by specifying:</p>
1211 <pre class="prettyprint lang-config">
1212 <Directory "/path-to-nfs-files">
1217 <p>Please note that the per-directory and .htaccess configuration
1218 of <code class="directive">EnableSendfile</code> is not supported by
1219 <code class="module"><a href="../mod/mod_cache_disk.html">mod_cache_disk</a></code>.
1220 Only global definition of <code class="directive">EnableSendfile</code>
1221 is taken into account by the module.
1225 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1226 <div class="directive-section"><h2><a name="Error" id="Error">Error</a> <a name="error" id="error">Directive</a></h2>
1227 <table class="directive">
1228 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Abort configuration parsing with a custom error message</td></tr>
1229 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Error <var>message</var></code></td></tr>
1230 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1231 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1232 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1233 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.3.9 and later</td></tr>
1235 <p>If an error can be detected within the configuration, this
1236 directive can be used to generate a custom error message, and halt
1237 configuration parsing. The typical use is for reporting required
1238 modules which are missing from the configuration.</p>
1240 <pre class="prettyprint lang-config">
1242 # ensure that mod_include is loaded
1243 <IfModule !include_module>
1244 Error "mod_include is required by mod_foo. Load it with LoadModule."
1247 # ensure that exactly one of SSL,NOSSL is defined
1248 <IfDefine SSL>
1249 <IfDefine NOSSL>
1250 Error "Both SSL and NOSSL are defined. Define only one of them."
1253 <IfDefine !SSL>
1254 <IfDefine !NOSSL>
1255 Error "Either SSL or NOSSL must be defined."
1263 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1264 <div class="directive-section"><h2><a name="ErrorDocument" id="ErrorDocument">ErrorDocument</a> <a name="errordocument" id="errordocument">Directive</a></h2>
1265 <table class="directive">
1266 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>What the server will return to the client
1267 in case of an error</td></tr>
1268 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ErrorDocument <var>error-code</var> <var>document</var></code></td></tr>
1269 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1270 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1271 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1272 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1274 <p>In the event of a problem or error, Apache httpd can be configured
1275 to do one of four things,</p>
1278 <li>output a simple hardcoded error message</li>
1280 <li>output a customized message</li>
1282 <li>redirect to a local <var>URL-path</var> to handle the
1285 <li>redirect to an external <var>URL</var> to handle the
1289 <p>The first option is the default, while options 2-4 are
1290 configured using the <code class="directive">ErrorDocument</code>
1291 directive, which is followed by the HTTP response code and a URL
1292 or a message. Apache httpd will sometimes offer additional information
1293 regarding the problem/error.</p>
1295 <p>URLs can begin with a slash (/) for local web-paths (relative
1296 to the <code class="directive"><a href="#documentroot">DocumentRoot</a></code>), or be a
1297 full URL which the client can resolve. Alternatively, a message
1298 can be provided to be displayed by the browser. Examples:</p>
1300 <pre class="prettyprint lang-config">
1301 ErrorDocument 500 http://foo.example.com/cgi-bin/tester
1302 ErrorDocument 404 /cgi-bin/bad_urls.pl
1303 ErrorDocument 401 /subscription_info.html
1304 ErrorDocument 403 "Sorry can't allow you access today"
1305 ErrorDocument 403 Forbidden!
1309 <p>Additionally, the special value <code>default</code> can be used
1310 to specify Apache httpd's simple hardcoded message. While not required
1311 under normal circumstances, <code>default</code> will restore
1312 Apache httpd's simple hardcoded message for configurations that would
1313 otherwise inherit an existing <code class="directive">ErrorDocument</code>.</p>
1315 <pre class="prettyprint lang-config">
1316 ErrorDocument 404 /cgi-bin/bad_urls.pl
1318 <Directory /web/docs>
1319 ErrorDocument 404 default
1324 <p>Note that when you specify an <code class="directive">ErrorDocument</code>
1325 that points to a remote URL (ie. anything with a method such as
1326 <code>http</code> in front of it), Apache HTTP Server will send a redirect to the
1327 client to tell it where to find the document, even if the
1328 document ends up being on the same server. This has several
1329 implications, the most important being that the client will not
1330 receive the original error status code, but instead will
1331 receive a redirect status code. This in turn can confuse web
1332 robots and other clients which try to determine if a URL is
1333 valid using the status code. In addition, if you use a remote
1334 URL in an <code>ErrorDocument 401</code>, the client will not
1335 know to prompt the user for a password since it will not
1336 receive the 401 status code. Therefore, <strong>if you use an
1337 <code>ErrorDocument 401</code> directive then it must refer to a local
1338 document.</strong></p>
1340 <p>Microsoft Internet Explorer (MSIE) will by default ignore
1341 server-generated error messages when they are "too small" and substitute
1342 its own "friendly" error messages. The size threshold varies depending on
1343 the type of error, but in general, if you make your error document
1344 greater than 512 bytes, then MSIE will show the server-generated
1345 error rather than masking it. More information is available in
1346 Microsoft Knowledge Base article <a href="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q294807">Q294807</a>.</p>
1348 <p>Although most error messages can be overridden, there are certain
1349 circumstances where the internal messages are used regardless of the
1350 setting of <code class="directive"><a href="#errordocument">ErrorDocument</a></code>. In
1351 particular, if a malformed request is detected, normal request processing
1352 will be immediately halted and the internal error message returned.
1353 This is necessary to guard against security problems caused by
1356 <p>If you are using mod_proxy, you may wish to enable
1357 <code class="directive"><a href="../mod/mod_proxy.html#proxyerroroverride">ProxyErrorOverride</a></code> so that you can provide
1358 custom error messages on behalf of your Origin servers. If you don't enable ProxyErrorOverride,
1359 Apache httpd will not generate custom error documents for proxied content.</p>
1363 <li><a href="../custom-error.html">documentation of
1364 customizable responses</a></li>
1367 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1368 <div class="directive-section"><h2><a name="ErrorLog" id="ErrorLog">ErrorLog</a> <a name="errorlog" id="errorlog">Directive</a></h2>
1369 <table class="directive">
1370 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Location where the server will log errors</td></tr>
1371 <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>
1372 <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>
1373 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1374 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1375 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1377 <p>The <code class="directive">ErrorLog</code> directive sets the name of
1378 the file to which the server will log any errors it encounters. If
1379 the <var>file-path</var> is not absolute then it is assumed to be
1380 relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1382 <pre class="prettyprint lang-config">ErrorLog "/var/log/httpd/error_log"</pre>
1385 <p>If the <var>file-path</var>
1386 begins with a pipe character "<code>|</code>" then it is assumed to be a
1387 command to spawn to handle the error log.</p>
1389 <pre class="prettyprint lang-config">ErrorLog "|/usr/local/bin/httpd_errors"</pre>
1392 <p>See the notes on <a href="../logs.html#piped">piped logs</a> for
1393 more information.</p>
1395 <p>Using <code>syslog</code> instead of a filename enables logging
1396 via syslogd(8) if the system supports it. The default is to use
1397 syslog facility <code>local7</code>, but you can override this by
1398 using the <code>syslog:<var>facility</var></code> syntax where
1399 <var>facility</var> can be one of the names usually documented in
1400 syslog(1). The facility is effectively global, and if it is changed
1401 in individual virtual hosts, the final facility specified affects the
1404 <pre class="prettyprint lang-config">ErrorLog syslog:user</pre>
1407 <p>SECURITY: See the <a href="../misc/security_tips.html#serverroot">security tips</a>
1408 document for details on why your security could be compromised
1409 if the directory where log files are stored is writable by
1410 anyone other than the user that starts the server.</p>
1411 <div class="warning"><h3>Note</h3>
1412 <p>When entering a file path on non-Unix platforms, care should be taken
1413 to make sure that only forward slashes are used even though the platform
1414 may allow the use of back slashes. In general it is a good idea to always
1415 use forward slashes throughout the configuration files.</p>
1420 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1421 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1424 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1425 <div class="directive-section"><h2><a name="ErrorLogFormat" id="ErrorLogFormat">ErrorLogFormat</a> <a name="errorlogformat" id="errorlogformat">Directive</a></h2>
1426 <table class="directive">
1427 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Format specification for error log entries</td></tr>
1428 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code> ErrorLogFormat [connection|request] <var>format</var></code></td></tr>
1429 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1430 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1431 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1432 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.3.9 and later</td></tr>
1434 <p><code class="directive">ErrorLogFormat</code> allows to specify what
1435 supplementary information is logged in the error log in addition to the
1436 actual log message.</p>
1438 <pre class="prettyprint lang-config">
1440 ErrorLogFormat "[%t] [%l] [pid %P] %F: %E: [client %a] %M"
1444 <p>Specifying <code>connection</code> or <code>request</code> as first
1445 parameter allows to specify additional formats, causing additional
1446 information to be logged when the first message is logged for a specific
1447 connection or request, respectively. This additional information is only
1448 logged once per connection/request. If a connection or request is processed
1449 without causing any log message, the additional information is not logged
1452 <p>It can happen that some format string items do not produce output. For
1453 example, the Referer header is only present if the log message is
1454 associated to a request and the log message happens at a time when the
1455 Referer header has already been read from the client. If no output is
1456 produced, the default behavior is to delete everything from the preceding
1457 space character to the next space character. This means the log line is
1458 implicitly divided into fields on non-whitespace to whitespace transitions.
1459 If a format string item does not produce output, the whole field is
1460 omitted. For example, if the remote address <code>%a</code> in the log
1461 format <code>[%t] [%l] [%a] %M </code> is not available, the surrounding
1462 brackets are not logged either. Space characters can be escaped with a
1463 backslash to prevent them from delimiting a field. The combination '% '
1464 (percent space) is a zero-width field delimiter that does not produce any
1467 <p>The above behavior can be changed by adding modifiers to the format
1468 string item. A <code>-</code> (minus) modifier causes a minus to be logged if the
1469 respective item does not produce any output. In once-per-connection/request
1470 formats, it is also possible to use the <code>+</code> (plus) modifier. If an
1471 item with the plus modifier does not produce any output, the whole line is
1474 <p>A number as modifier can be used to assign a log severity level to a
1475 format item. The item will only be logged if the severity of the log
1476 message is not higher than the specified log severity level. The number can
1477 range from 1 (alert) over 4 (warn) and 7 (debug) to 15 (trace8).</p>
1479 <p>For example, here's what would happen if you added modifiers to
1480 the <code>%{Referer}i</code> token, which logs the
1481 <code>Referer</code> request header.</p>
1483 <table class="bordered"><tr class="header"><th>Modified Token</th><th>Meaning</th></tr>
1485 <td><code>%-{Referer}i</code></td>
1486 <td>Logs a <code>-</code> if <code>Referer</code> is not set.</td>
1489 <td><code>%+{Referer}i</code></td>
1490 <td>Omits the entire line if <code>Referer</code> is not set.</td>
1493 <td><code>%4{Referer}i</code></td>
1494 <td>Logs the <code>Referer</code> only if the log message severity
1495 is higher than 4.</td>
1499 <p>Some format string items accept additional parameters in braces.</p>
1501 <table class="bordered"><tr class="header"><th>Format String</th> <th>Description</th></tr>
1502 <tr><td><code>%%</code></td>
1503 <td>The percent sign</td></tr>
1504 <tr class="odd"><td><code>%a</code></td>
1505 <td>Client IP address and port of the request</td></tr>
1506 <tr><td><code>%{c}a</code></td>
1507 <td>Underlying peer IP address and port of the connection (see the
1508 <code class="module"><a href="../mod/mod_remoteip.html">mod_remoteip</a></code> module)</td></tr>
1509 <tr class="odd"><td><code>%A</code></td>
1510 <td>Local IP-address and port</td></tr>
1511 <tr><td><code>%{<em>name</em>}e</code></td>
1512 <td>Request environment variable <em>name</em></td></tr>
1513 <tr class="odd"><td><code>%E</code></td>
1514 <td>APR/OS error status code and string</td></tr>
1515 <tr><td><code>%F</code></td>
1516 <td>Source file name and line number of the log call</td></tr>
1517 <tr class="odd"><td><code>%{<em>name</em>}i</code></td>
1518 <td>Request header <em>name</em></td></tr>
1519 <tr><td><code>%k</code></td>
1520 <td>Number of keep-alive requests on this connection</td></tr>
1521 <tr class="odd"><td><code>%l</code></td>
1522 <td>Loglevel of the message</td></tr>
1523 <tr><td><code>%L</code></td>
1524 <td>Log ID of the request</td></tr>
1525 <tr class="odd"><td><code>%{c}L</code></td>
1526 <td>Log ID of the connection</td></tr>
1527 <tr><td><code>%{C}L</code></td>
1528 <td>Log ID of the connection if used in connection scope, empty otherwise</td></tr>
1529 <tr class="odd"><td><code>%m</code></td>
1530 <td>Name of the module logging the message</td></tr>
1531 <tr><td><code>%M</code></td>
1532 <td>The actual log message</td></tr>
1533 <tr class="odd"><td><code>%{<em>name</em>}n</code></td>
1534 <td>Request note <em>name</em></td></tr>
1535 <tr><td><code>%P</code></td>
1536 <td>Process ID of current process</td></tr>
1537 <tr class="odd"><td><code>%T</code></td>
1538 <td>Thread ID of current thread</td></tr>
1539 <tr><td><code>%{g}T</code></td>
1540 <td>System unique thread ID of current thread (the same ID as
1541 displayed by e.g. <code>top</code>; currently Linux only)</td></tr>
1542 <tr class="odd"><td><code>%t</code></td>
1543 <td>The current time</td></tr>
1544 <tr><td><code>%{u}t</code></td>
1545 <td>The current time including micro-seconds</td></tr>
1546 <tr class="odd"><td><code>%{cu}t</code></td>
1547 <td>The current time in compact ISO 8601 format, including
1548 micro-seconds</td></tr>
1549 <tr><td><code>%v</code></td>
1550 <td>The canonical <code class="directive"><a href="#servername">ServerName</a></code>
1551 of the current server.</td></tr>
1552 <tr class="odd"><td><code>%V</code></td>
1553 <td>The server name of the server serving the request according to the
1554 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code>
1556 <tr><td><code>\ </code> (backslash space)</td>
1557 <td>Non-field delimiting space</td></tr>
1558 <tr class="odd"><td><code>% </code> (percent space)</td>
1559 <td>Field delimiter (no output)</td></tr>
1562 <p>The log ID format <code>%L</code> produces a unique id for a connection
1563 or request. This can be used to correlate which log lines belong to the
1564 same connection or request, which request happens on which connection.
1565 A <code>%L</code> format string is also available in
1566 <code class="module"><a href="../mod/mod_log_config.html">mod_log_config</a></code>, to allow to correlate access log entries
1567 with error log lines. If <code class="module"><a href="../mod/mod_unique_id.html">mod_unique_id</a></code> is loaded, its
1568 unique id will be used as log ID for requests.</p>
1570 <pre class="prettyprint lang-config">
1571 #Example (default format)
1572 ErrorLogFormat "[%{u}t] [%-m:%l] [pid %P:tid %T] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"
1576 <p>This would result in error messages such as:</p>
1578 <div class="example"><p><code>
1579 [Thu May 12 08:28:57.652118 2011] [core:error] [pid 8777:tid 4326490112] [client ::1:58619] File does not exist: /usr/local/apache2/htdocs/favicon.ico
1582 <p>Notice that, as discussed above, some fields are omitted
1583 entirely because they are not defined.</p>
1585 <pre class="prettyprint lang-config">
1586 #Example (similar to the 2.2.x format)
1587 ErrorLogFormat "[%t] [%l] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"
1591 <pre class="prettyprint lang-config">
1592 #Advanced example with request/connection log IDs
1593 ErrorLogFormat "[%{uc}t] [%-m:%-l] [R:%L] [C:%{C}L] %7F: %E: %M"
1594 ErrorLogFormat request "[%{uc}t] [R:%L] Request %k on C:%{c}L pid:%P tid:%T"
1595 ErrorLogFormat request "[%{uc}t] [R:%L] UA:'%+{User-Agent}i'"
1596 ErrorLogFormat request "[%{uc}t] [R:%L] Referer:'%+{Referer}i'"
1597 ErrorLogFormat connection "[%{uc}t] [C:%{c}L] local\ %a remote\ %A"
1604 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
1605 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1606 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1609 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1610 <div class="directive-section"><h2><a name="ExtendedStatus" id="ExtendedStatus">ExtendedStatus</a> <a name="extendedstatus" id="extendedstatus">Directive</a></h2>
1611 <table class="directive">
1612 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Keep track of extended status information for each
1614 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ExtendedStatus On|Off</code></td></tr>
1615 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ExtendedStatus Off[*]</code></td></tr>
1616 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
1617 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1618 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1620 <p>This option tracks additional data per worker about the
1621 currently executing request, and a utilization summary; you
1622 can see these variables during runtime by configuring
1623 <code class="module"><a href="../mod/mod_status.html">mod_status</a></code>. Note that other modules may
1624 rely on this scoreboard.</p>
1626 <p>This setting applies to the entire server, and cannot be
1627 enabled or disabled on a virtualhost-by-virtualhost basis.
1628 The collection of extended status information can slow down
1629 the server. Also note that this setting cannot be changed
1630 during a graceful restart.</p>
1633 <p>Note that loading <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> will change
1634 the default behavior to ExtendedStatus On, while other
1635 third party modules may do the same. Such modules rely on
1636 collecting detailed information about the state of all workers.
1637 The default is changed by <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> beginning
1638 with version 2.3.6; the previous default was always Off.</p>
1643 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1644 <div class="directive-section"><h2><a name="FileETag" id="FileETag">FileETag</a> <a name="fileetag" id="fileetag">Directive</a></h2>
1645 <table class="directive">
1646 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>File attributes used to create the ETag
1647 HTTP response header for static files</td></tr>
1648 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>FileETag <var>component</var> ...</code></td></tr>
1649 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>FileETag MTime Size</code></td></tr>
1650 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1651 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1652 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1653 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1654 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>The default used to be "INode MTime Size" in 2.3.14 and
1658 The <code class="directive">FileETag</code> directive configures the file
1659 attributes that are used to create the <code>ETag</code> (entity
1660 tag) response header field when the document is based on a static file.
1661 (The <code>ETag</code> value is used in cache management to save
1662 network bandwidth.) The
1663 <code class="directive">FileETag</code> directive allows you to choose
1664 which of these -- if any -- should be used. The recognized keywords are:
1668 <dt><strong>INode</strong></dt>
1669 <dd>The file's i-node number will be included in the calculation</dd>
1670 <dt><strong>MTime</strong></dt>
1671 <dd>The date and time the file was last modified will be included</dd>
1672 <dt><strong>Size</strong></dt>
1673 <dd>The number of bytes in the file will be included</dd>
1674 <dt><strong>All</strong></dt>
1675 <dd>All available fields will be used. This is equivalent to:
1676 <pre class="prettyprint lang-config">FileETag INode MTime Size</pre>
1678 <dt><strong>None</strong></dt>
1679 <dd>If a document is file-based, no <code>ETag</code> field will be
1680 included in the response</dd>
1683 <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
1684 keywords may be prefixed with either <code>+</code> or <code>-</code>,
1685 which allow changes to be made to the default setting inherited
1686 from a broader scope. Any keyword appearing without such a prefix
1687 immediately and completely cancels the inherited setting.</p>
1689 <p>If a directory's configuration includes
1690 <code>FileETag INode MTime Size</code>, and a
1691 subdirectory's includes <code>FileETag -INode</code>,
1692 the setting for that subdirectory (which will be inherited by
1693 any sub-subdirectories that don't override it) will be equivalent to
1694 <code>FileETag MTime Size</code>.</p>
1695 <div class="warning"><h3>Warning</h3>
1696 Do not change the default for directories or locations that have WebDAV
1697 enabled and use <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> as a storage provider.
1698 <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> uses <code>MTime Size</code>
1699 as a fixed format for <code>ETag</code> comparisons on conditional requests.
1700 These conditional requests will break if the <code>ETag</code> format is
1701 changed via <code class="directive">FileETag</code>.
1703 <div class="note"><h3>Server Side Includes</h3>
1704 An ETag is not generated for responses parsed by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>,
1705 since the response entity can change without a change of the INode, MTime, or Size
1706 of the static file with embedded SSI directives.
1711 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1712 <div class="directive-section"><h2><a name="Files" id="Files"><Files></a> <a name="files" id="files">Directive</a></h2>
1713 <table class="directive">
1714 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to matched
1716 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Files <var>filename</var>> ... </Files></code></td></tr>
1717 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1718 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1719 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1720 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1722 <p>The <code class="directive"><Files></code> directive
1723 limits the scope of the enclosed directives by filename. It is comparable
1724 to the <code class="directive"><a href="#directory"><Directory></a></code>
1725 and <code class="directive"><a href="#location"><Location></a></code>
1726 directives. It should be matched with a <code></Files></code>
1727 directive. The directives given within this section will be applied to
1728 any object with a basename (last component of filename) matching the
1729 specified filename. <code class="directive"><Files></code>
1730 sections are processed in the order they appear in the
1731 configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
1732 <code>.htaccess</code> files are read, but before <code class="directive"><a href="#location"><Location></a></code> sections. Note
1733 that <code class="directive"><Files></code> can be nested
1734 inside <code class="directive"><a href="#directory"><Directory></a></code> sections to restrict the
1735 portion of the filesystem they apply to.</p>
1737 <p>The <var>filename</var> argument should include a filename, or
1738 a wild-card string, where <code>?</code> matches any single character,
1739 and <code>*</code> matches any sequences of characters.</p>
1740 <pre class="prettyprint lang-config">
1741 <Files "cat.html">
1742 # Insert stuff that applies to cat.html here
1745 <Files "?at.*">
1746 # This would apply to cat.html, bat.html, hat.php and so on.
1750 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
1751 can also be used, with the addition of the
1752 <code>~</code> character. For example:</p>
1754 <pre class="prettyprint lang-config">
1755 <Files ~ "\.(gif|jpe?g|png)$">
1761 <p>would match most common Internet graphics formats. <code class="directive"><a href="#filesmatch"><FilesMatch></a></code> is preferred,
1764 <p>Note that unlike <code class="directive"><a href="#directory"><Directory></a></code> and <code class="directive"><a href="#location"><Location></a></code> sections, <code class="directive"><Files></code> sections can be used inside
1765 <code>.htaccess</code> files. This allows users to control access to
1766 their own files, at a file-by-file level.</p>
1771 <li><a href="../sections.html">How <Directory>, <Location>
1772 and <Files> sections work</a> for an explanation of how these
1773 different sections are combined when a request is received</li>
1776 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1777 <div class="directive-section"><h2><a name="FilesMatch" id="FilesMatch"><FilesMatch></a> <a name="filesmatch" id="filesmatch">Directive</a></h2>
1778 <table class="directive">
1779 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to regular-expression matched
1781 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><FilesMatch <var>regex</var>> ... </FilesMatch></code></td></tr>
1782 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1783 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1784 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1785 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1787 <p>The <code class="directive"><FilesMatch></code> directive
1788 limits the scope of the enclosed directives by filename, just as the
1789 <code class="directive"><a href="#files"><Files></a></code> directive
1790 does. However, it accepts a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular
1791 expression</a>. For example:</p>
1793 <pre class="prettyprint lang-config">
1794 <FilesMatch "\.(gif|jpe?g|png)$">
1800 <p>would match most common Internet graphics formats.</p>
1804 <li><a href="../sections.html">How <Directory>, <Location>
1805 and <Files> sections work</a> for an explanation of how these
1806 different sections are combined when a request is received</li>
1809 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1810 <div class="directive-section"><h2><a name="ForceType" id="ForceType">ForceType</a> <a name="forcetype" id="forcetype">Directive</a></h2>
1811 <table class="directive">
1812 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be served with the specified
1813 media type in the HTTP Content-Type header field</td></tr>
1814 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ForceType <var>media-type</var>|None</code></td></tr>
1815 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
1816 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1817 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1818 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1819 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Moved to the core in Apache httpd 2.0</td></tr>
1821 <p>When placed into an <code>.htaccess</code> file or a
1822 <code class="directive"><a href="#directory"><Directory></a></code>, or
1823 <code class="directive"><a href="#location"><Location></a></code> or
1824 <code class="directive"><a href="#files"><Files></a></code>
1825 section, this directive forces all matching files to be served
1826 with the content type identification given by
1827 <var>media-type</var>. For example, if you had a directory full of
1828 GIF files, but did not want to label them all with <code>.gif</code>,
1829 you might want to use:</p>
1831 <pre class="prettyprint lang-config">ForceType image/gif</pre>
1834 <p>Note that this directive overrides other indirect media type
1835 associations defined in mime.types or via the
1836 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code>.</p>
1838 <p>You can also override more general
1839 <code class="directive">ForceType</code> settings
1840 by using the value of <code>None</code>:</p>
1842 <pre class="prettyprint lang-config">
1843 # force all files to be image/gif:
1844 <Location /images>
1848 # but normal mime-type associations here:
1849 <Location /images/mixed>
1855 <p>This directive primarily overrides the content types generated for
1856 static files served out of the filesystem. For resources other than
1857 static files, where the generator of the response typically specifies
1858 a Content-Type, this directive has no effect.</p>
1862 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1863 <div class="directive-section"><h2><a name="GprofDir" id="GprofDir">GprofDir</a> <a name="gprofdir" id="gprofdir">Directive</a></h2>
1864 <table class="directive">
1865 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory to write gmon.out profiling data to. </td></tr>
1866 <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>
1867 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1868 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1869 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1871 <p>When the server has been compiled with gprof profiling support,
1872 <code class="directive">GprofDir</code> causes <code>gmon.out</code> files to
1873 be written to the specified directory when the process exits. If the
1874 argument ends with a percent symbol ('%'), subdirectories are created
1875 for each process id.</p>
1877 <p>This directive currently only works with the <code class="module"><a href="../mod/prefork.html">prefork</a></code>
1881 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1882 <div class="directive-section"><h2><a name="HostnameLookups" id="HostnameLookups">HostnameLookups</a> <a name="hostnamelookups" id="hostnamelookups">Directive</a></h2>
1883 <table class="directive">
1884 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables DNS lookups on client IP addresses</td></tr>
1885 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>HostnameLookups On|Off|Double</code></td></tr>
1886 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>HostnameLookups Off</code></td></tr>
1887 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1888 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1889 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1891 <p>This directive enables DNS lookups so that host names can be
1892 logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
1893 The value <code>Double</code> refers to doing double-reverse
1894 DNS lookup. That is, after a reverse lookup is performed, a forward
1895 lookup is then performed on that result. At least one of the IP
1896 addresses in the forward lookup must match the original
1897 address. (In "tcpwrappers" terminology this is called
1898 <code>PARANOID</code>.)</p>
1900 <p>Regardless of the setting, when <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code> is
1901 used for controlling access by hostname, a double reverse lookup
1902 will be performed. This is necessary for security. Note that the
1903 result of this double-reverse isn't generally available unless you
1904 set <code>HostnameLookups Double</code>. For example, if only
1905 <code>HostnameLookups On</code> and a request is made to an object
1906 that is protected by hostname restrictions, regardless of whether
1907 the double-reverse fails or not, CGIs will still be passed the
1908 single-reverse result in <code>REMOTE_HOST</code>.</p>
1910 <p>The default is <code>Off</code> in order to save the network
1911 traffic for those sites that don't truly need the reverse
1912 lookups done. It is also better for the end users because they
1913 don't have to suffer the extra latency that a lookup entails.
1914 Heavily loaded sites should leave this directive
1915 <code>Off</code>, since DNS lookups can take considerable
1916 amounts of time. The utility <code class="program"><a href="../programs/logresolve.html">logresolve</a></code>, compiled by
1917 default to the <code>bin</code> subdirectory of your installation
1918 directory, can be used to look up host names from logged IP addresses
1921 <p>Finally, if you have <a href="mod_authz_host.html#reqhost">hostname-based Require
1922 directives</a>, a hostname lookup will be performed regardless of
1923 the setting of <code>HostnameLookups</code>.</p>
1926 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1927 <div class="directive-section"><h2><a name="If" id="If"><If></a> <a name="if" id="if">Directive</a></h2>
1928 <table class="directive">
1929 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is
1930 satisfied by a request at runtime</td></tr>
1931 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><If <var>expression</var>> ... </If></code></td></tr>
1932 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1933 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1934 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1935 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1937 <p>The <code class="directive"><If></code> directive
1938 evaluates an expression at runtime, and applies the enclosed
1939 directives if and only if the expression evaluates to true.
1942 <pre class="prettyprint lang-config"><If "-z req('Host')"></pre>
1945 <p>would match HTTP/1.0 requests without a <var>Host:</var> header.
1946 Expressions may contain various shell-like operators for string
1947 comparison (<code>=</code>, <code>!=</code>, <code><</code>, ...),
1948 integer comparison (<code>-eq</code>, <code>-ne</code>, ...),
1949 and others (<code>-n</code>, <code>-z</code>, <code>-f</code>, ...).
1950 It is also possible to use regular expressions, </p>
1952 <pre class="prettyprint lang-config"><If "%{QUERY_STRING} =~ /(delete|commit)=.*?elem/"></pre>
1955 <p>shell-like pattern matches and many other operations. These operations
1956 can be done on request headers (<code>req</code>), environment variables
1957 (<code>env</code>), and a large number of other properties. The full
1958 documentation is available in <a href="../expr.html">Expressions in
1959 Apache HTTP Server</a>.</p>
1964 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
1965 for a complete reference and more examples.</li>
1966 <li><code class="directive"><a href="#elseif"><ElseIf></a></code></li>
1967 <li><code class="directive"><a href="#else"><Else></a></code></li>
1968 <li><a href="../sections.html">How <Directory>, <Location>,
1969 <Files> sections work</a> for an explanation of how these
1970 different sections are combined when a request is received.
1971 <code class="directive"><If></code>,
1972 <code class="directive"><ElseIf></code>, and
1973 <code class="directive"><Else></code> are applied last.</li>
1976 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1977 <div class="directive-section"><h2><a name="IfDefine" id="IfDefine"><IfDefine></a> <a name="ifdefine" id="ifdefine">Directive</a></h2>
1978 <table class="directive">
1979 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that will be processed only
1980 if a test is true at startup</td></tr>
1981 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfDefine [!]<var>parameter-name</var>> ...
1982 </IfDefine></code></td></tr>
1983 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1984 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1985 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1986 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1988 <p>The <code><IfDefine <var>test</var>>...</IfDefine>
1989 </code> section is used to mark directives that are conditional. The
1990 directives within an <code class="directive"><IfDefine></code>
1991 section are only processed if the <var>test</var> is true. If <var>
1992 test</var> is false, everything between the start and end markers is
1995 <p>The <var>test</var> in the <code class="directive"><IfDefine></code> section directive can be one of two forms:</p>
1998 <li><var>parameter-name</var></li>
2000 <li><code>!</code><var>parameter-name</var></li>
2003 <p>In the former case, the directives between the start and end
2004 markers are only processed if the parameter named
2005 <var>parameter-name</var> is defined. The second format reverses
2006 the test, and only processes the directives if
2007 <var>parameter-name</var> is <strong>not</strong> defined.</p>
2009 <p>The <var>parameter-name</var> argument is a define as given on the
2010 <code class="program"><a href="../programs/httpd.html">httpd</a></code> command line via <code>-D<var>parameter</var>
2011 </code> at the time the server was started or by the <code class="directive"><a href="#define">Define</a></code> directive.</p>
2013 <p><code class="directive"><IfDefine></code> sections are
2014 nest-able, which can be used to implement simple
2015 multiple-parameter tests. Example:</p>
2017 <div class="example"><p><code>httpd -DReverseProxy -DUseCache -DMemCache ...</code></p></div>
2018 <pre class="prettyprint lang-config">
2019 <IfDefine ReverseProxy>
2020 LoadModule proxy_module modules/mod_proxy.so
2021 LoadModule proxy_http_module modules/mod_proxy_http.so
2022 <IfDefine UseCache>
2023 LoadModule cache_module modules/mod_cache.so
2024 <IfDefine MemCache>
2025 LoadModule mem_cache_module modules/mod_mem_cache.so
2027 <IfDefine !MemCache>
2028 LoadModule cache_disk_module modules/mod_cache_disk.so
2036 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2037 <div class="directive-section"><h2><a name="IfModule" id="IfModule"><IfModule></a> <a name="ifmodule" id="ifmodule">Directive</a></h2>
2038 <table class="directive">
2039 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that are processed conditional on the
2040 presence or absence of a specific module</td></tr>
2041 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfModule [!]<var>module-file</var>|<var>module-identifier</var>> ...
2042 </IfModule></code></td></tr>
2043 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2044 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2045 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2046 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2047 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Module identifiers are available in version 2.1 and
2050 <p>The <code><IfModule <var>test</var>>...</IfModule></code>
2051 section is used to mark directives that are conditional on the presence of
2052 a specific module. The directives within an <code class="directive"><IfModule></code> section are only processed if the <var>test</var>
2053 is true. If <var>test</var> is false, everything between the start and
2054 end markers is ignored.</p>
2056 <p>The <var>test</var> in the <code class="directive"><IfModule></code> section directive can be one of two forms:</p>
2059 <li><var>module</var></li>
2061 <li>!<var>module</var></li>
2064 <p>In the former case, the directives between the start and end
2065 markers are only processed if the module named <var>module</var>
2066 is included in Apache httpd -- either compiled in or
2067 dynamically loaded using <code class="directive"><a href="../mod/mod_so.html#loadmodule">LoadModule</a></code>. The second format reverses the test,
2068 and only processes the directives if <var>module</var> is
2069 <strong>not</strong> included.</p>
2071 <p>The <var>module</var> argument can be either the module identifier or
2072 the file name of the module, at the time it was compiled. For example,
2073 <code>rewrite_module</code> is the identifier and
2074 <code>mod_rewrite.c</code> is the file name. If a module consists of
2075 several source files, use the name of the file containing the string
2076 <code>STANDARD20_MODULE_STUFF</code>.</p>
2078 <p><code class="directive"><IfModule></code> sections are
2079 nest-able, which can be used to implement simple multiple-module
2082 <div class="note">This section should only be used if you need to have one
2083 configuration file that works whether or not a specific module
2084 is available. In normal operation, directives need not be
2085 placed in <code class="directive"><IfModule></code>
2089 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2090 <div class="directive-section"><h2><a name="Include" id="Include">Include</a> <a name="include" id="include">Directive</a></h2>
2091 <table class="directive">
2092 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2093 the server configuration files</td></tr>
2094 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Include <var>file-path</var>|<var>directory-path</var>|<var>wildcard</var></code></td></tr>
2095 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2096 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2097 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2098 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Wildcard matching available in 2.0.41 and later, directory
2099 wildcard matching available in 2.3.6 and later</td></tr>
2101 <p>This directive allows inclusion of other configuration files
2102 from within the server configuration files.</p>
2104 <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used
2105 in the filename or directory parts of the path to include several files
2106 at once, in alphabetical order. In addition, if
2107 <code class="directive">Include</code> points to a directory, rather than a file,
2108 Apache httpd will read all files in that directory and any subdirectory.
2109 However, including entire directories is not recommended, because it is
2110 easy to accidentally leave temporary files in a directory that can cause
2111 <code class="program"><a href="../programs/httpd.html">httpd</a></code> to fail. Instead, we encourage you to use the
2112 wildcard syntax shown below, to include files that match a particular
2113 pattern, such as *.conf, for example.</p>
2115 <p>The <code class="directive"><a href="#include">Include</a></code> directive will
2116 <strong>fail with an error</strong> if a wildcard expression does not
2117 match any file. The <code class="directive"><a href="#includeoptional">IncludeOptional</a></code>
2118 directive can be used if non-matching wildcards should be ignored.</p>
2120 <p>The file path specified may be an absolute path, or may be relative
2121 to the <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory.</p>
2125 <pre class="prettyprint lang-config">
2126 Include /usr/local/apache2/conf/ssl.conf
2127 Include /usr/local/apache2/conf/vhosts/*.conf
2131 <p>Or, providing paths relative to your <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory:</p>
2133 <pre class="prettyprint lang-config">
2134 Include conf/ssl.conf
2135 Include conf/vhosts/*.conf
2139 <p>Wildcards may be included in the directory or file portion of the
2140 path. This example will fail if there is no subdirectory in conf/vhosts
2141 that contains at least one *.conf file:</p>
2143 <pre class="prettyprint lang-config">Include conf/vhosts/*/*.conf</pre>
2146 <p>Alternatively, the following command will just be ignored in case of
2147 missing files or directories:</p>
2149 <pre class="prettyprint lang-config">IncludeOptional conf/vhosts/*/*.conf</pre>
2155 <li><code class="directive"><a href="#includeoptional">IncludeOptional</a></code></li>
2156 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
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="IncludeOptional" id="IncludeOptional">IncludeOptional</a> <a name="includeoptional" id="includeoptional">Directive</a></h2>
2161 <table class="directive">
2162 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2163 the server configuration files</td></tr>
2164 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>IncludeOptional <var>file-path</var>|<var>directory-path</var>|<var>wildcard</var></code></td></tr>
2165 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2166 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2167 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2168 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in 2.3.6 and later</td></tr>
2170 <p>This directive allows inclusion of other configuration files
2171 from within the server configuration files. It works identically to the
2172 <code class="directive"><a href="#include">Include</a></code> directive, with the
2173 exception that if wildcards do not match any file or directory, the
2174 <code class="directive"><a href="#includeoptional">IncludeOptional</a></code> directive will be
2175 silently ignored instead of causing an error.</p>
2179 <li><code class="directive"><a href="#include">Include</a></code></li>
2180 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2183 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2184 <div class="directive-section"><h2><a name="KeepAlive" id="KeepAlive">KeepAlive</a> <a name="keepalive" id="keepalive">Directive</a></h2>
2185 <table class="directive">
2186 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables HTTP persistent connections</td></tr>
2187 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAlive On|Off</code></td></tr>
2188 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAlive On</code></td></tr>
2189 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2190 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2191 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2193 <p>The Keep-Alive extension to HTTP/1.0 and the persistent
2194 connection feature of HTTP/1.1 provide long-lived HTTP sessions
2195 which allow multiple requests to be sent over the same TCP
2196 connection. In some cases this has been shown to result in an
2197 almost 50% speedup in latency times for HTML documents with
2198 many images. To enable Keep-Alive connections, set
2199 <code>KeepAlive On</code>.</p>
2201 <p>For HTTP/1.0 clients, Keep-Alive connections will only be
2202 used if they are specifically requested by a client. In
2203 addition, a Keep-Alive connection with an HTTP/1.0 client can
2204 only be used when the length of the content is known in
2205 advance. This implies that dynamic content such as CGI output,
2206 SSI pages, and server-generated directory listings will
2207 generally not use Keep-Alive connections to HTTP/1.0 clients.
2208 For HTTP/1.1 clients, persistent connections are the default
2209 unless otherwise specified. If the client requests it, chunked
2210 encoding will be used in order to send content of unknown
2211 length over persistent connections.</p>
2213 <p>When a client uses a Keep-Alive connection it will be counted
2214 as a single "request" for the <code class="directive"><a href="../mod/mpm_common.html#maxconnectionsperchild">MaxConnectionsPerChild</a></code> directive, regardless
2215 of how many requests are sent using the connection.</p>
2219 <li><code class="directive"><a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></code></li>
2222 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2223 <div class="directive-section"><h2><a name="KeepAliveTimeout" id="KeepAliveTimeout">KeepAliveTimeout</a> <a name="keepalivetimeout" id="keepalivetimeout">Directive</a></h2>
2224 <table class="directive">
2225 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for subsequent
2226 requests on a persistent connection</td></tr>
2227 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAliveTimeout <var>num</var>[ms]</code></td></tr>
2228 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAliveTimeout 5</code></td></tr>
2229 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2230 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2231 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2232 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Specifying a value in milliseconds is available in
2233 Apache httpd 2.3.2 and later</td></tr>
2235 <p>The number of seconds Apache httpd will wait for a subsequent
2236 request before closing the connection. By adding a postfix of ms the
2237 timeout can be also set in milliseconds. Once a request has been
2238 received, the timeout value specified by the
2239 <code class="directive"><a href="#timeout">Timeout</a></code> directive applies.</p>
2241 <p>Setting <code class="directive">KeepAliveTimeout</code> to a high value
2242 may cause performance problems in heavily loaded servers. The
2243 higher the timeout, the more server processes will be kept
2244 occupied waiting on connections with idle clients.</p>
2246 <p>In a name-based virtual host context, the value of the first
2247 defined virtual host best matching the local IP and port will be used.</p>
2250 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2251 <div class="directive-section"><h2><a name="Limit" id="Limit"><Limit></a> <a name="limit" id="limit">Directive</a></h2>
2252 <table class="directive">
2253 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict enclosed access controls to only certain HTTP
2255 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Limit <var>method</var> [<var>method</var>] ... > ...
2256 </Limit></code></td></tr>
2257 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2258 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2259 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2260 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2262 <p>Access controls are normally effective for
2263 <strong>all</strong> access methods, and this is the usual
2264 desired behavior. <strong>In the general case, access control
2265 directives should not be placed within a
2266 <code class="directive"><Limit></code> section.</strong></p>
2268 <p>The purpose of the <code class="directive"><Limit></code>
2269 directive is to restrict the effect of the access controls to the
2270 nominated HTTP methods. For all other methods, the access
2271 restrictions that are enclosed in the <code class="directive"><Limit></code> bracket <strong>will have no
2272 effect</strong>. The following example applies the access control
2273 only to the methods <code>POST</code>, <code>PUT</code>, and
2274 <code>DELETE</code>, leaving all other methods unprotected:</p>
2276 <pre class="prettyprint lang-config">
2277 <Limit POST PUT DELETE>
2283 <p>The method names listed can be one or more of: <code>GET</code>,
2284 <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
2285 <code>CONNECT</code>, <code>OPTIONS</code>,
2286 <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
2287 <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
2288 <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
2289 case-sensitive.</strong> If <code>GET</code> is used it will also
2290 restrict <code>HEAD</code> requests. The <code>TRACE</code> method
2291 cannot be limited (see <code class="directive"><a href="#traceenable">TraceEnable</a></code>).</p>
2293 <div class="warning">A <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section should always be
2294 used in preference to a <code class="directive"><Limit></code>
2295 section when restricting access, since a <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section provides protection
2296 against arbitrary methods.</div>
2298 <p>The <code class="directive"><Limit></code> and
2299 <code class="directive"><a href="#limitexcept"><LimitExcept></a></code>
2300 directives may be nested. In this case, each successive level of
2301 <code class="directive"><Limit></code> or <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> directives must
2302 further restrict the set of methods to which access controls apply.</p>
2304 <div class="warning">When using
2305 <code class="directive"><Limit></code> or
2306 <code class="directive"><LimitExcept></code> directives with
2307 the <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directive,
2308 note that the first <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code>
2309 to succeed authorizes the request, regardless of the presence of other
2310 <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directives.</div>
2312 <p>For example, given the following configuration, all users will
2313 be authorized for <code>POST</code> requests, and the
2314 <code>Require group editors</code> directive will be ignored
2317 <pre class="prettyprint lang-config">
2318 <LimitExcept GET>
2320 </LimitExcept>
2322 Require group editors
2328 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2329 <div class="directive-section"><h2><a name="LimitExcept" id="LimitExcept"><LimitExcept></a> <a name="limitexcept" id="limitexcept">Directive</a></h2>
2330 <table class="directive">
2331 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict access controls to all HTTP methods
2332 except the named ones</td></tr>
2333 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LimitExcept <var>method</var> [<var>method</var>] ... > ...
2334 </LimitExcept></code></td></tr>
2335 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2336 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2337 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2338 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2340 <p><code class="directive"><LimitExcept></code> and
2341 <code></LimitExcept></code> are used to enclose
2342 a group of access control directives which will then apply to any
2343 HTTP access method <strong>not</strong> listed in the arguments;
2344 i.e., it is the opposite of a <code class="directive"><a href="#limit"><Limit></a></code> section and can be used to control
2345 both standard and nonstandard/unrecognized methods. See the
2346 documentation for <code class="directive"><a href="#limit"><Limit></a></code> for more details.</p>
2350 <pre class="prettyprint lang-config">
2351 <LimitExcept POST GET>
2353 </LimitExcept>
2359 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2360 <div class="directive-section"><h2><a name="LimitInternalRecursion" id="LimitInternalRecursion">LimitInternalRecursion</a> <a name="limitinternalrecursion" id="limitinternalrecursion">Directive</a></h2>
2361 <table class="directive">
2362 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine maximum number of internal redirects and nested
2363 subrequests</td></tr>
2364 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitInternalRecursion <var>number</var> [<var>number</var>]</code></td></tr>
2365 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitInternalRecursion 10</code></td></tr>
2366 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2367 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2368 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2369 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.0.47 and later</td></tr>
2371 <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
2372 redirects the original request to a CGI script. A subrequest is Apache httpd's
2373 mechanism to find out what would happen for some URI if it were requested.
2374 For example, <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> uses subrequests to look for the
2375 files listed in the <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
2378 <p><code class="directive">LimitInternalRecursion</code> prevents the server
2379 from crashing when entering an infinite loop of internal redirects or
2380 subrequests. Such loops are usually caused by misconfigurations.</p>
2382 <p>The directive stores two different limits, which are evaluated on
2383 per-request basis. The first <var>number</var> is the maximum number of
2384 internal redirects, that may follow each other. The second <var>number</var>
2385 determines, how deep subrequests may be nested. If you specify only one
2386 <var>number</var>, it will be assigned to both limits.</p>
2388 <pre class="prettyprint lang-config">LimitInternalRecursion 5</pre>
2392 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2393 <div class="directive-section"><h2><a name="LimitRequestBody" id="LimitRequestBody">LimitRequestBody</a> <a name="limitrequestbody" id="limitrequestbody">Directive</a></h2>
2394 <table class="directive">
2395 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restricts the total size of the HTTP request body sent
2396 from the client</td></tr>
2397 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestBody <var>bytes</var></code></td></tr>
2398 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestBody 0</code></td></tr>
2399 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2400 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2401 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2402 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2404 <p>This directive specifies the number of <var>bytes</var> from 0
2405 (meaning unlimited) to 2147483647 (2GB) that are allowed in a
2406 request body. See the note below for the limited applicability
2407 to proxy requests.</p>
2409 <p>The <code class="directive">LimitRequestBody</code> directive allows
2410 the user to set a limit on the allowed size of an HTTP request
2411 message body within the context in which the directive is given
2412 (server, per-directory, per-file or per-location). If the client
2413 request exceeds that limit, the server will return an error
2414 response instead of servicing the request. The size of a normal
2415 request message body will vary greatly depending on the nature of
2416 the resource and the methods allowed on that resource. CGI scripts
2417 typically use the message body for retrieving form information.
2418 Implementations of the <code>PUT</code> method will require
2419 a value at least as large as any representation that the server
2420 wishes to accept for that resource.</p>
2422 <p>This directive gives the server administrator greater
2423 control over abnormal client request behavior, which may be
2424 useful for avoiding some forms of denial-of-service
2427 <p>If, for example, you are permitting file upload to a particular
2428 location, and wish to limit the size of the uploaded file to 100K,
2429 you might use the following directive:</p>
2431 <pre class="prettyprint lang-config">LimitRequestBody 102400</pre>
2434 <div class="note"><p>For a full description of how this directive is interpreted by
2435 proxy requests, see the <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> documentation.</p>
2440 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2441 <div class="directive-section"><h2><a name="LimitRequestFields" id="LimitRequestFields">LimitRequestFields</a> <a name="limitrequestfields" id="limitrequestfields">Directive</a></h2>
2442 <table class="directive">
2443 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of HTTP request header fields that
2444 will be accepted from the client</td></tr>
2445 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFields <var>number</var></code></td></tr>
2446 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFields 100</code></td></tr>
2447 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2448 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2449 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2451 <p><var>Number</var> is an integer from 0 (meaning unlimited) to
2452 32767. The default value is defined by the compile-time
2453 constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
2456 <p>The <code class="directive">LimitRequestFields</code> directive allows
2457 the server administrator to modify the limit on the number of
2458 request header fields allowed in an HTTP request. A server needs
2459 this value to be larger than the number of fields that a normal
2460 client request might include. The number of request header fields
2461 used by a client rarely exceeds 20, but this may vary among
2462 different client implementations, often depending upon the extent
2463 to which a user has configured their browser to support detailed
2464 content negotiation. Optional HTTP extensions are often expressed
2465 using request header fields.</p>
2467 <p>This directive gives the server administrator greater
2468 control over abnormal client request behavior, which may be
2469 useful for avoiding some forms of denial-of-service attacks.
2470 The value should be increased if normal clients see an error
2471 response from the server that indicates too many fields were
2472 sent in the request.</p>
2476 <pre class="prettyprint lang-config">LimitRequestFields 50</pre>
2479 <div class="warning"><h3>Warning</h3>
2480 <p> When name-based virtual hosting is used, the value for this
2481 directive is taken from the default (first-listed) virtual host for the
2482 local IP and port combination.</p>
2487 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2488 <div class="directive-section"><h2><a name="LimitRequestFieldSize" id="LimitRequestFieldSize">LimitRequestFieldSize</a> <a name="limitrequestfieldsize" id="limitrequestfieldsize">Directive</a></h2>
2489 <table class="directive">
2490 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of the HTTP request header allowed from the
2492 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFieldSize <var>bytes</var></code></td></tr>
2493 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFieldSize 8190</code></td></tr>
2494 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2495 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2496 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2498 <p>This directive specifies the number of <var>bytes</var>
2499 that will be allowed in an HTTP request header.</p>
2501 <p>The <code class="directive">LimitRequestFieldSize</code> directive
2502 allows the server administrator to set the limit
2503 on the allowed size of an HTTP request header field. A server
2504 needs this value to be large enough to hold any one header field
2505 from a normal client request. The size of a normal request header
2506 field will vary greatly among different client implementations,
2507 often depending upon the extent to which a user has configured
2508 their browser to support detailed content negotiation. SPNEGO
2509 authentication headers can be up to 12392 bytes.</p>
2511 <p>This directive gives the server administrator greater
2512 control over abnormal client request behavior, which may be
2513 useful for avoiding some forms of denial-of-service attacks.</p>
2517 <pre class="prettyprint lang-config">LimitRequestFieldSize 4094</pre>
2520 <div class="note">Under normal conditions, the value should not be changed from
2523 <div class="warning"><h3>Warning</h3>
2524 <p> When name-based virtual hosting is used, the value for this
2525 directive is taken from the default (first-listed) virtual host best
2526 matching the current IP address and port combination.</p>
2530 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2531 <div class="directive-section"><h2><a name="LimitRequestLine" id="LimitRequestLine">LimitRequestLine</a> <a name="limitrequestline" id="limitrequestline">Directive</a></h2>
2532 <table class="directive">
2533 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limit the size of the HTTP request line that will be accepted
2534 from the client</td></tr>
2535 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestLine <var>bytes</var></code></td></tr>
2536 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestLine 8190</code></td></tr>
2537 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2538 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2539 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2541 <p>This directive sets the number of <var>bytes</var> that will be
2542 allowed on the HTTP request-line.</p>
2544 <p>The <code class="directive">LimitRequestLine</code> directive allows
2545 the server administrator to set the limit on the allowed size
2546 of a client's HTTP request-line. Since the request-line consists of the
2547 HTTP method, URI, and protocol version, the
2548 <code class="directive">LimitRequestLine</code> directive places a
2549 restriction on the length of a request-URI allowed for a request
2550 on the server. A server needs this value to be large enough to
2551 hold any of its resource names, including any information that
2552 might be passed in the query part of a <code>GET</code> request.</p>
2554 <p>This directive gives the server administrator greater
2555 control over abnormal client request behavior, which may be
2556 useful for avoiding some forms of denial-of-service attacks.</p>
2560 <pre class="prettyprint lang-config">LimitRequestLine 4094</pre>
2563 <div class="note">Under normal conditions, the value should not be changed from
2564 the default. Also, you can't set this higher than 8190 without
2565 modifying the source and rebuilding.</div>
2567 <div class="warning"><h3>Warning</h3>
2568 <p> When name-based virtual hosting is used, the value for this
2569 directive is taken from the default (first-listed) virtual host best
2570 matching the current IP address and port combination.</p>
2575 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2576 <div class="directive-section"><h2><a name="LimitXMLRequestBody" id="LimitXMLRequestBody">LimitXMLRequestBody</a> <a name="limitxmlrequestbody" id="limitxmlrequestbody">Directive</a></h2>
2577 <table class="directive">
2578 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of an XML-based request body</td></tr>
2579 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitXMLRequestBody <var>bytes</var></code></td></tr>
2580 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitXMLRequestBody 1000000</code></td></tr>
2581 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2582 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2583 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2584 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2586 <p>Limit (in bytes) on maximum size of an XML-based request
2587 body. A value of <code>0</code> will disable any checking.</p>
2591 <pre class="prettyprint lang-config">LimitXMLRequestBody 0</pre>
2596 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2597 <div class="directive-section"><h2><a name="Location" id="Location"><Location></a> <a name="location" id="location">Directive</a></h2>
2598 <table class="directive">
2599 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to matching
2601 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Location
2602 <var>URL-path</var>|<var>URL</var>> ... </Location></code></td></tr>
2603 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2604 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2605 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2607 <p>The <code class="directive"><Location></code> directive
2608 limits the scope of the enclosed directives by URL. It is similar to the
2609 <code class="directive"><a href="#directory"><Directory></a></code>
2610 directive, and starts a subsection which is terminated with a
2611 <code></Location></code> directive. <code class="directive"><Location></code> sections are processed in the
2612 order they appear in the configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
2613 <code>.htaccess</code> files are read, and after the <code class="directive"><a href="#files"><Files></a></code> sections.</p>
2615 <p><code class="directive"><Location></code> sections operate
2616 completely outside the filesystem. This has several consequences.
2617 Most importantly, <code class="directive"><Location></code>
2618 directives should not be used to control access to filesystem
2619 locations. Since several different URLs may map to the same
2620 filesystem location, such access controls may by circumvented.</p>
2622 <p>The enclosed directives will be applied to the request if the path component
2623 of the URL meets <em>any</em> of the following criteria:
2626 <li>The specified location matches exactly the path component of the URL.
2628 <li>The specified location, which ends in a forward slash, is a prefix
2629 of the path component of the URL (treated as a context root).
2631 <li>The specified location, with the addition of a trailing slash, is a
2632 prefix of the path component of the URL (also treated as a context root).
2636 In the example below, where no trailing slash is used, requests to
2637 /private1, /private1/ and /private1/file.txt will have the enclosed
2638 directives applied, but /private1other would not.
2640 <pre class="prettyprint lang-config">
2641 <Location /private1>
2647 In the example below, where a trailing slash is used, requests to
2648 /private2/ and /private2/file.txt will have the enclosed
2649 directives applied, but /private2 and /private2other would not.
2651 <pre class="prettyprint lang-config">
2652 <Location /private2<em>/</em>>
2658 <div class="note"><h3>When to use <code class="directive"><Location></code></h3>
2660 <p>Use <code class="directive"><Location></code> to apply
2661 directives to content that lives outside the filesystem. For
2662 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
2663 <code><Location /></code>, which is an easy way to
2664 apply a configuration to the entire server.</p>
2667 <p>For all origin (non-proxy) requests, the URL to be matched is a
2668 URL-path of the form <code>/path/</code>. <em>No scheme, hostname,
2669 port, or query string may be included.</em> For proxy requests, the
2670 URL to be matched is of the form
2671 <code>scheme://servername/path</code>, and you must include the
2674 <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
2675 any single character, and <code>*</code> matches any sequences of
2676 characters. Neither wildcard character matches a / in the URL-path.</p>
2678 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
2679 can also be used, with the addition of the <code>~</code>
2680 character. For example:</p>
2682 <pre class="prettyprint lang-config">
2683 <Location ~ "/(extra|special)/data">
2689 <p>would match URLs that contained the substring <code>/extra/data</code>
2690 or <code>/special/data</code>. The directive <code class="directive"><a href="#locationmatch"><LocationMatch></a></code> behaves
2691 identical to the regex version of <code class="directive"><Location></code>, and is preferred, for the
2692 simple reason that <code>~</code> is hard to distinguish from
2693 <code>-</code> in many fonts.</p>
2695 <p>The <code class="directive"><Location></code>
2696 functionality is especially useful when combined with the
2697 <code class="directive"><a href="#sethandler">SetHandler</a></code>
2698 directive. For example, to enable status requests, but allow them
2699 only from browsers at <code>example.com</code>, you might use:</p>
2701 <pre class="prettyprint lang-config">
2702 <Location /status>
2703 SetHandler server-status
2704 Require host example.com
2709 <div class="note"><h3>Note about / (slash)</h3>
2710 <p>The slash character has special meaning depending on where in a
2711 URL it appears. People may be used to its behavior in the filesystem
2712 where multiple adjacent slashes are frequently collapsed to a single
2713 slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
2714 <code>/home/foo</code>). In URL-space this is not necessarily true.
2715 The <code class="directive"><a href="#locationmatch"><LocationMatch></a></code>
2716 directive and the regex version of <code class="directive"><Location></code> require you to explicitly specify multiple
2717 slashes if that is your intention.</p>
2719 <p>For example, <code><LocationMatch ^/abc></code> would match
2720 the request URL <code>/abc</code> but not the request URL <code>
2721 //abc</code>. The (non-regex) <code class="directive"><Location></code> directive behaves similarly when used for
2722 proxy requests. But when (non-regex) <code class="directive"><Location></code> is used for non-proxy requests it will
2723 implicitly match multiple slashes with a single slash. For example,
2724 if you specify <code><Location /abc/def></code> and the
2725 request is to <code>/abc//def</code> then it will match.</p>
2730 <li><a href="../sections.html">How <Directory>, <Location>
2731 and <Files> sections work</a> for an explanation of how these
2732 different sections are combined when a request is received.</li>
2733 <li><code class="directive"><a href="#locationmatch">LocationMatch</a></code></li>
2736 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2737 <div class="directive-section"><h2><a name="LocationMatch" id="LocationMatch"><LocationMatch></a> <a name="locationmatch" id="locationmatch">Directive</a></h2>
2738 <table class="directive">
2739 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to regular-expression
2740 matching URLs</td></tr>
2741 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LocationMatch
2742 <var>regex</var>> ... </LocationMatch></code></td></tr>
2743 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2744 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2745 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2747 <p>The <code class="directive"><LocationMatch></code> directive
2748 limits the scope of the enclosed directives by URL, in an identical manner
2749 to <code class="directive"><a href="#location"><Location></a></code>. However,
2750 it takes a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
2751 as an argument instead of a simple string. For example:</p>
2753 <pre class="prettyprint lang-config">
2754 <LocationMatch "/(extra|special)/data">
2756 </LocationMatch>
2760 <p>would match URLs that contained the substring <code>/extra/data</code>
2761 or <code>/special/data</code>.</p>
2765 <li><a href="../sections.html">How <Directory>, <Location>
2766 and <Files> sections work</a> for an explanation of how these
2767 different sections are combined when a request is received</li>
2770 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2771 <div class="directive-section"><h2><a name="LogLevel" id="LogLevel">LogLevel</a> <a name="loglevel" id="loglevel">Directive</a></h2>
2772 <table class="directive">
2773 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Controls the verbosity of the ErrorLog</td></tr>
2774 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel [<var>module</var>:]<var>level</var>
2775 [<var>module</var>:<var>level</var>] ...
2777 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LogLevel warn</code></td></tr>
2778 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2779 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2780 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2781 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Per-module and per-directory configuration is available in
2782 Apache HTTP Server 2.3.6 and later</td></tr>
2784 <p><code class="directive">LogLevel</code> adjusts the verbosity of the
2785 messages recorded in the error logs (see <code class="directive"><a href="#errorlog">ErrorLog</a></code> directive). The following
2786 <var>level</var>s are available, in order of decreasing
2789 <table class="bordered">
2792 <th><strong>Level</strong> </th>
2794 <th><strong>Description</strong> </th>
2796 <th><strong>Example</strong> </th>
2800 <td><code>emerg</code> </td>
2802 <td>Emergencies - system is unusable.</td>
2804 <td>"Child cannot open lock file. Exiting"</td>
2808 <td><code>alert</code> </td>
2810 <td>Action must be taken immediately.</td>
2812 <td>"getpwuid: couldn't determine user name from uid"</td>
2816 <td><code>crit</code> </td>
2818 <td>Critical Conditions.</td>
2820 <td>"socket: Failed to get a socket, exiting child"</td>
2824 <td><code>error</code> </td>
2826 <td>Error conditions.</td>
2828 <td>"Premature end of script headers"</td>
2832 <td><code>warn</code> </td>
2834 <td>Warning conditions.</td>
2836 <td>"child process 1234 did not exit, sending another
2841 <td><code>notice</code> </td>
2843 <td>Normal but significant condition.</td>
2845 <td>"httpd: caught SIGBUS, attempting to dump core in
2850 <td><code>info</code> </td>
2852 <td>Informational.</td>
2854 <td>"Server seems busy, (you may need to increase
2855 StartServers, or Min/MaxSpareServers)..."</td>
2859 <td><code>debug</code> </td>
2861 <td>Debug-level messages</td>
2863 <td>"Opening config file ..."</td>
2866 <td><code>trace1</code> </td>
2868 <td>Trace messages</td>
2870 <td>"proxy: FTP: control connection complete"</td>
2873 <td><code>trace2</code> </td>
2875 <td>Trace messages</td>
2877 <td>"proxy: CONNECT: sending the CONNECT request to the remote proxy"</td>
2880 <td><code>trace3</code> </td>
2882 <td>Trace messages</td>
2884 <td>"openssl: Handshake: start"</td>
2887 <td><code>trace4</code> </td>
2889 <td>Trace messages</td>
2891 <td>"read from buffered SSL brigade, mode 0, 17 bytes"</td>
2894 <td><code>trace5</code> </td>
2896 <td>Trace messages</td>
2898 <td>"map lookup FAILED: map=rewritemap key=keyname"</td>
2901 <td><code>trace6</code> </td>
2903 <td>Trace messages</td>
2905 <td>"cache lookup FAILED, forcing new map lookup"</td>
2908 <td><code>trace7</code> </td>
2910 <td>Trace messages, dumping large amounts of data</td>
2912 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2915 <td><code>trace8</code> </td>
2917 <td>Trace messages, dumping large amounts of data</td>
2919 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2923 <p>When a particular level is specified, messages from all
2924 other levels of higher significance will be reported as well.
2925 <em>E.g.</em>, when <code>LogLevel info</code> is specified,
2926 then messages with log levels of <code>notice</code> and
2927 <code>warn</code> will also be posted.</p>
2929 <p>Using a level of at least <code>crit</code> is
2934 <pre class="prettyprint lang-config">LogLevel notice</pre>
2937 <div class="note"><h3>Note</h3>
2938 <p>When logging to a regular file messages of the level
2939 <code>notice</code> cannot be suppressed and thus are always
2940 logged. However, this doesn't apply when logging is done
2941 using <code>syslog</code>.</p>
2944 <p>Specifying a level without a module name will reset the level
2945 for all modules to that level. Specifying a level with a module
2946 name will set the level for that module only. It is possible to
2947 use the module source file name, the module identifier, or the
2948 module identifier with the trailing <code>_module</code> omitted
2949 as module specification. This means the following three specifications
2952 <pre class="prettyprint lang-config">
2953 LogLevel info ssl:warn
2954 LogLevel info mod_ssl.c:warn
2955 LogLevel info ssl_module:warn
2959 <p>It is also possible to change the level per directory:</p>
2961 <pre class="prettyprint lang-config">
2963 <Directory "/usr/local/apache/htdocs/app">
2970 Per directory loglevel configuration only affects messages that are
2971 logged after the request has been parsed and that are associated with
2972 the request. Log messages which are associated with the connection or
2973 the server are not affected.
2977 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2978 <div class="directive-section"><h2><a name="MaxKeepAliveRequests" id="MaxKeepAliveRequests">MaxKeepAliveRequests</a> <a name="maxkeepaliverequests" id="maxkeepaliverequests">Directive</a></h2>
2979 <table class="directive">
2980 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of requests allowed on a persistent
2981 connection</td></tr>
2982 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxKeepAliveRequests <var>number</var></code></td></tr>
2983 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxKeepAliveRequests 100</code></td></tr>
2984 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2985 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2986 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2988 <p>The <code class="directive">MaxKeepAliveRequests</code> directive
2989 limits the number of requests allowed per connection when
2990 <code class="directive"><a href="#keepalive">KeepAlive</a></code> is on. If it is
2991 set to <code>0</code>, unlimited requests will be allowed. We
2992 recommend that this setting be kept to a high value for maximum
2993 server performance.</p>
2997 <pre class="prettyprint lang-config">MaxKeepAliveRequests 500</pre>
3001 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3002 <div class="directive-section"><h2><a name="MaxRangeOverlaps" id="MaxRangeOverlaps">MaxRangeOverlaps</a> <a name="maxrangeoverlaps" id="maxrangeoverlaps">Directive</a></h2>
3003 <table class="directive">
3004 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of overlapping ranges (eg: <code>100-200,150-300</code>) allowed before returning the complete
3006 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxRangeOverlaps default | unlimited | none | <var>number-of-ranges</var></code></td></tr>
3007 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeOverlaps 20</code></td></tr>
3008 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3009 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3010 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3011 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3013 <p>The <code class="directive">MaxRangeOverlaps</code> directive
3014 limits the number of overlapping HTTP ranges the server is willing to
3015 return to the client. If more overlapping ranges then permitted are requested,
3016 the complete resource is returned instead.</p>
3019 <dt><strong>default</strong></dt>
3020 <dd>Limits the number of overlapping ranges to a compile-time default of 20.</dd>
3022 <dt><strong>none</strong></dt>
3023 <dd>No overlapping Range headers are allowed.</dd>
3025 <dt><strong>unlimited</strong></dt>
3026 <dd>The server does not limit the number of overlapping ranges it is
3027 willing to satisfy.</dd>
3029 <dt><var>number-of-ranges</var></dt>
3030 <dd>A positive number representing the maximum number of overlapping ranges the
3031 server is willing to satisfy.</dd>
3035 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3036 <div class="directive-section"><h2><a name="MaxRangeReversals" id="MaxRangeReversals">MaxRangeReversals</a> <a name="maxrangereversals" id="maxrangereversals">Directive</a></h2>
3037 <table class="directive">
3038 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of range reversals (eg: <code>100-200,50-70</code>) allowed before returning the complete
3040 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxRangeReversals default | unlimited | none | <var>number-of-ranges</var></code></td></tr>
3041 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeReversals 20</code></td></tr>
3042 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3043 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3044 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3045 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3047 <p>The <code class="directive">MaxRangeReversals</code> directive
3048 limits the number of HTTP Range reversals the server is willing to
3049 return to the client. If more ranges reversals then permitted are requested,
3050 the complete resource is returned instead.</p>
3053 <dt><strong>default</strong></dt>
3054 <dd>Limits the number of range reversals to a compile-time default of 20.</dd>
3056 <dt><strong>none</strong></dt>
3057 <dd>No Range reversals headers are allowed.</dd>
3059 <dt><strong>unlimited</strong></dt>
3060 <dd>The server does not limit the number of range reversals it is
3061 willing to satisfy.</dd>
3063 <dt><var>number-of-ranges</var></dt>
3064 <dd>A positive number representing the maximum number of range reversals the
3065 server is willing to satisfy.</dd>
3069 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3070 <div class="directive-section"><h2><a name="MaxRanges" id="MaxRanges">MaxRanges</a> <a name="maxranges" id="maxranges">Directive</a></h2>
3071 <table class="directive">
3072 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of ranges allowed before returning the complete
3074 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxRanges default | unlimited | none | <var>number-of-ranges</var></code></td></tr>
3075 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRanges 200</code></td></tr>
3076 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3077 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3078 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3079 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3081 <p>The <code class="directive">MaxRanges</code> directive
3082 limits the number of HTTP ranges the server is willing to
3083 return to the client. If more ranges then permitted are requested,
3084 the complete resource is returned instead.</p>
3087 <dt><strong>default</strong></dt>
3088 <dd>Limits the number of ranges to a compile-time default of 200.</dd>
3090 <dt><strong>none</strong></dt>
3091 <dd>Range headers are ignored.</dd>
3093 <dt><strong>unlimited</strong></dt>
3094 <dd>The server does not limit the number of ranges it is
3095 willing to satisfy.</dd>
3097 <dt><var>number-of-ranges</var></dt>
3098 <dd>A positive number representing the maximum number of ranges the
3099 server is willing to satisfy.</dd>
3103 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3104 <div class="directive-section"><h2><a name="Mutex" id="Mutex">Mutex</a> <a name="mutex" id="mutex">Directive</a></h2>
3105 <table class="directive">
3106 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures mutex mechanism and lock file directory for all
3107 or specified mutexes</td></tr>
3108 <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>
3109 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Mutex default</code></td></tr>
3110 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3111 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3112 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3113 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.4 and later</td></tr>
3115 <p>The <code class="directive">Mutex</code> directive sets the mechanism,
3116 and optionally the lock file location, that httpd and modules use
3117 to serialize access to resources. Specify <code>default</code> as
3118 the first argument to change the settings for all mutexes; specify
3119 a mutex name (see table below) as the first argument to override
3120 defaults only for that mutex.</p>
3122 <p>The <code class="directive">Mutex</code> directive is typically used in
3123 the following exceptional situations:</p>
3126 <li>change the mutex mechanism when the default mechanism selected
3127 by <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> has a functional or performance
3130 <li>change the directory used by file-based mutexes when the
3131 default directory does not support locking</li>
3134 <div class="note"><h3>Supported modules</h3>
3135 <p>This directive only configures mutexes which have been registered
3136 with the core server using the <code>ap_mutex_register()</code> API.
3137 All modules bundled with httpd support the <code class="directive">Mutex</code>
3138 directive, but third-party modules may not. Consult the documentation
3139 of the third-party module, which must indicate the mutex name(s) which
3140 can be configured if this directive is supported.</p>
3143 <p>The following mutex <em>mechanisms</em> are available:</p>
3145 <li><code>default | yes</code>
3146 <p>This selects the default locking implementation, as determined by
3147 <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a>. The default locking implementation can
3148 be displayed by running <code class="program"><a href="../programs/httpd.html">httpd</a></code> with the
3149 <code>-V</code> option.</p></li>
3151 <li><code>none | no</code>
3152 <p>This effectively disables the mutex, and is only allowed for a
3153 mutex if the module indicates that it is a valid choice. Consult the
3154 module documentation for more information.</p></li>
3156 <li><code>posixsem</code>
3157 <p>This is a mutex variant based on a Posix semaphore.</p>
3159 <div class="warning"><h3>Warning</h3>
3160 <p>The semaphore ownership is not recovered if a thread in the process
3161 holding the mutex segfaults, resulting in a hang of the web server.</p>
3165 <li><code>sysvsem</code>
3166 <p>This is a mutex variant based on a SystemV IPC semaphore.</p>
3168 <div class="warning"><h3>Warning</h3>
3169 <p>It is possible to "leak" SysV semaphores if processes crash
3170 before the semaphore is removed.</p>
3173 <div class="warning"><h3>Security</h3>
3174 <p>The semaphore API allows for a denial of service attack by any
3175 CGIs running under the same uid as the webserver (<em>i.e.</em>,
3176 all CGIs, unless you use something like <code class="program"><a href="../programs/suexec.html">suexec</a></code>
3177 or <code>cgiwrapper</code>).</p>
3181 <li><code>sem</code>
3182 <p>This selects the "best" available semaphore implementation, choosing
3183 between Posix and SystemV IPC semaphores, in that order.</p></li>
3185 <li><code>pthread</code>
3186 <p>This is a mutex variant based on cross-process Posix thread
3189 <div class="warning"><h3>Warning</h3>
3190 <p>On most systems, if a child process terminates abnormally while
3191 holding a mutex that uses this implementation, the server will deadlock
3192 and stop responding to requests. When this occurs, the server will
3193 require a manual restart to recover.</p>
3194 <p>Solaris is a notable exception as it provides a mechanism which
3195 usually allows the mutex to be recovered after a child process
3196 terminates abnormally while holding a mutex.</p>
3197 <p>If your system implements the
3198 <code>pthread_mutexattr_setrobust_np()</code> function, you may be able
3199 to use the <code>pthread</code> option safely.</p>
3203 <li><code>fcntl:/path/to/mutex</code>
3204 <p>This is a mutex variant where a physical (lock-)file and the
3205 <code>fcntl()</code> function are used as the mutex.</p>
3207 <div class="warning"><h3>Warning</h3>
3208 <p>When multiple mutexes based on this mechanism are used within
3209 multi-threaded, multi-process environments, deadlock errors (EDEADLK)
3210 can be reported for valid mutex operations if <code>fcntl()</code>
3211 is not thread-aware, such as on Solaris.</p>
3215 <li><code>flock:/path/to/mutex</code>
3216 <p>This is similar to the <code>fcntl:/path/to/mutex</code> method
3217 with the exception that the <code>flock()</code> function is used to
3218 provide file locking.</p></li>
3220 <li><code>file:/path/to/mutex</code>
3221 <p>This selects the "best" available file locking implementation,
3222 choosing between <code>fcntl</code> and <code>flock</code>, in that
3226 <p>Most mechanisms are only available on selected platforms, where the
3227 underlying platform and <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> support it. Mechanisms
3228 which aren't available on all platforms are <em>posixsem</em>,
3229 <em>sysvsem</em>, <em>sem</em>, <em>pthread</em>, <em>fcntl</em>,
3230 <em>flock</em>, and <em>file</em>.</p>
3232 <p>With the file-based mechanisms <em>fcntl</em> and <em>flock</em>,
3233 the path, if provided, is a directory where the lock file will be created.
3234 The default directory is httpd's run-time file directory,
3235 <code class="directive"><a href="#defaultruntimedir">DefaultRuntimeDir</a></code>. If a relative
3236 path is provided, it is relative to
3237 <code class="directive"><a href="#defaultruntimedir">DefaultRuntimeDir</a></code>. Always use a local
3238 disk filesystem for <code>/path/to/mutex</code> and never a directory residing
3239 on a NFS- or AFS-filesystem. The basename of the file will be the mutex
3240 type, an optional instance string provided by the module, and unless the
3241 <code>OmitPID</code> keyword is specified, the process id of the httpd
3242 parent process will be appended to to make the file name unique, avoiding
3243 conflicts when multiple httpd instances share a lock file directory. For
3244 example, if the mutex name is <code>mpm-accept</code> and the lock file
3245 directory is <code>/var/httpd/locks</code>, the lock file name for the
3246 httpd instance with parent process id 12345 would be
3247 <code>/var/httpd/locks/mpm-accept.12345</code>.</p>
3249 <div class="warning"><h3>Security</h3>
3250 <p>It is best to <em>avoid</em> putting mutex files in a world-writable
3251 directory such as <code>/var/tmp</code> because someone could create
3252 a denial of service attack and prevent the server from starting by
3253 creating a lockfile with the same name as the one the server will try
3257 <p>The following table documents the names of mutexes used by httpd
3258 and bundled modules.</p>
3260 <table class="bordered"><tr class="header">
3263 <th>Protected resource</th>
3266 <td><code>mpm-accept</code></td>
3267 <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>
3268 <td>incoming connections, to avoid the thundering herd problem;
3269 for more information, refer to the
3270 <a href="../misc/perf-tuning.html">performance tuning</a>
3274 <td><code>authdigest-client</code></td>
3275 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3276 <td>client list in shared memory</td>
3279 <td><code>authdigest-opaque</code></td>
3280 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3281 <td>counter in shared memory</td>
3284 <td><code>ldap-cache</code></td>
3285 <td><code class="module"><a href="../mod/mod_ldap.html">mod_ldap</a></code></td>
3286 <td>LDAP result cache</td>
3289 <td><code>rewrite-map</code></td>
3290 <td><code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code></td>
3291 <td>communication with external mapping programs, to avoid
3292 intermixed I/O from multiple requests</td>
3295 <td><code>ssl-cache</code></td>
3296 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3297 <td>SSL session cache</td>
3300 <td><code>ssl-stapling</code></td>
3301 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3302 <td>OCSP stapling response cache</td>
3305 <td><code>watchdog-callback</code></td>
3306 <td><code class="module"><a href="../mod/mod_watchdog.html">mod_watchdog</a></code></td>
3307 <td>callback function of a particular client module</td>
3311 <p>The <code>OmitPID</code> keyword suppresses the addition of the httpd
3312 parent process id from the lock file name.</p>
3314 <p>In the following example, the mutex mechanism for the MPM accept
3315 mutex will be changed from the compiled-in default to <code>fcntl</code>,
3316 with the associated lock file created in directory
3317 <code>/var/httpd/locks</code>. The mutex mechanism for all other mutexes
3318 will be changed from the compiled-in default to <code>sysvsem</code>.</p>
3320 <pre class="prettyprint lang-config">
3321 Mutex sysvsem default
3322 Mutex fcntl:/var/httpd/locks mpm-accept
3327 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3328 <div class="directive-section"><h2><a name="NameVirtualHost" id="NameVirtualHost">NameVirtualHost</a> <a name="namevirtualhost" id="namevirtualhost">Directive</a></h2>
3329 <table class="directive">
3330 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>DEPRECATED: Designates an IP address for name-virtual
3332 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NameVirtualHost <var>addr</var>[:<var>port</var>]</code></td></tr>
3333 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3334 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3335 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3338 <p>Prior to 2.3.11, <code class="directive">NameVirtualHost</code> was required
3339 to instruct the server that a particular IP address and port combination
3340 was usable as a name-based virtual host. In 2.3.11 and later,
3341 any time an IP address and port combination is used in multiple virtual
3342 hosts, name-based virtual hosting is automatically enabled for that address.</p>
3344 <p>This directive currently has no effect.</p>
3348 <li><a href="../vhosts/">Virtual Hosts
3349 documentation</a></li>
3352 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3353 <div class="directive-section"><h2><a name="Options" id="Options">Options</a> <a name="options" id="options">Directive</a></h2>
3354 <table class="directive">
3355 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures what features are available in a particular
3357 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Options
3358 [+|-]<var>option</var> [[+|-]<var>option</var>] ...</code></td></tr>
3359 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Options FollowSymlinks</code></td></tr>
3360 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3361 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
3362 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3363 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3364 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>The default was changed from All to FollowSymlinks in 2.3.11</td></tr>
3366 <p>The <code class="directive">Options</code> directive controls which
3367 server features are available in a particular directory.</p>
3369 <p><var>option</var> can be set to <code>None</code>, in which
3370 case none of the extra features are enabled, or one or more of
3374 <dt><code>All</code></dt>
3376 <dd>All options except for <code>MultiViews</code>.</dd>
3378 <dt><code>ExecCGI</code></dt>
3381 Execution of CGI scripts using <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>
3384 <dt><code>FollowSymLinks</code></dt>
3387 The server will follow symbolic links in this directory. This is
3388 the default setting.
3390 <p>Even though the server follows the symlink it does <em>not</em>
3391 change the pathname used to match against <code class="directive"><a href="#directory"><Directory></a></code> sections.</p>
3393 <p>The <code>FollowSymLinks</code> and
3394 <code>SymLinksIfOwnerMatch</code> <code class="directive"><a href="#options">Options</a></code> work only in <code class="directive"><a href="#directory"><Directory></a></code> sections or
3395 <code>.htaccess</code> files.</p>
3397 <p>Omitting this option should not be considered a security restriction,
3398 since symlink testing is subject to race conditions that make it
3402 <dt><code>Includes</code></dt>
3405 Server-side includes provided by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
3408 <dt><code>IncludesNOEXEC</code></dt>
3412 Server-side includes are permitted, but the <code>#exec
3413 cmd</code> and <code>#exec cgi</code> are disabled. It is still
3414 possible to <code>#include virtual</code> CGI scripts from
3415 <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>ed
3418 <dt><code>Indexes</code></dt>
3421 If a URL which maps to a directory is requested, and there
3422 is no <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
3423 (<em>e.g.</em>, <code>index.html</code>) in that directory, then
3424 <code class="module"><a href="../mod/mod_autoindex.html">mod_autoindex</a></code> will return a formatted listing
3425 of the directory.</dd>
3427 <dt><code>MultiViews</code></dt>
3430 <a href="../content-negotiation.html">Content negotiated</a>
3431 "MultiViews" are allowed using
3432 <code class="module"><a href="../mod/mod_negotiation.html">mod_negotiation</a></code>.
3433 <div class="note"><h3>Note</h3> <p>This option gets ignored if set
3434 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>
3435 needs real resources to compare against and evaluate from.</p></div>
3438 <dt><code>SymLinksIfOwnerMatch</code></dt>
3440 <dd>The server will only follow symbolic links for which the
3441 target file or directory is owned by the same user id as the
3444 <div class="note"><h3>Note</h3>
3445 <p>The <code>FollowSymLinks</code> and
3446 <code>SymLinksIfOwnerMatch</code> <code class="directive"><a href="#options">Options</a></code> work only in <code class="directive"><a href="#directory"><Directory></a></code> sections or
3447 <code>.htaccess</code> files.</p>
3449 <p>This option should not be considered a security restriction,
3450 since symlink testing is subject to race conditions that make it
3455 <p>Normally, if multiple <code class="directive">Options</code> could
3456 apply to a directory, then the most specific one is used and
3457 others are ignored; the options are not merged. (See <a href="../sections.html#mergin">how sections are merged</a>.)
3458 However if <em>all</em> the options on the
3459 <code class="directive">Options</code> directive are preceded by a
3460 <code>+</code> or <code>-</code> symbol, the options are
3461 merged. Any options preceded by a <code>+</code> are added to the
3462 options currently in force, and any options preceded by a
3463 <code>-</code> are removed from the options currently in
3466 <div class="note"><h3>Note</h3>
3467 <p>Mixing <code class="directive">Options</code> with a <code>+</code> or
3468 <code>-</code> with those without is not valid syntax, and will be
3469 rejected during server startup by the syntax check with an abort.</p>
3472 <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>
3474 <pre class="prettyprint lang-config">
3475 <Directory "/web/docs">
3476 Options Indexes FollowSymLinks
3479 <Directory "/web/docs/spec">
3485 <p>then only <code>Includes</code> will be set for the
3486 <code>/web/docs/spec</code> directory. However if the second
3487 <code class="directive">Options</code> directive uses the <code>+</code> and
3488 <code>-</code> symbols:</p>
3490 <pre class="prettyprint lang-config">
3491 <Directory "/web/docs">
3492 Options Indexes FollowSymLinks
3495 <Directory "/web/docs/spec">
3496 Options +Includes -Indexes
3501 <p>then the options <code>FollowSymLinks</code> and
3502 <code>Includes</code> are set for the <code>/web/docs/spec</code>
3505 <div class="note"><h3>Note</h3>
3506 <p>Using <code>-IncludesNOEXEC</code> or
3507 <code>-Includes</code> disables server-side includes completely
3508 regardless of the previous setting.</p>
3511 <p>The default in the absence of any other settings is
3512 <code>FollowSymlinks</code>.</p>
3515 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3516 <div class="directive-section"><h2><a name="Protocol" id="Protocol">Protocol</a> <a name="protocol" id="protocol">Directive</a></h2>
3517 <table class="directive">
3518 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Protocol for a listening socket</td></tr>
3519 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Protocol <var>protocol</var></code></td></tr>
3520 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3521 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3522 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3523 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.1.5 and later.
3524 On Windows from Apache 2.3.3 and later.</td></tr>
3526 <p>This directive specifies the protocol used for a specific listening socket.
3527 The protocol is used to determine which module should handle a request, and
3528 to apply protocol specific optimizations with the <code class="directive">AcceptFilter</code>
3531 <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>
3533 <p>For example, if you are running <code>https</code> on a non-standard port, specify the protocol explicitly:</p>
3535 <pre class="prettyprint lang-config">Protocol https</pre>
3538 <p>You can also specify the protocol using the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code> directive.</p>
3542 <li><code class="directive"><a href="#acceptfilter">AcceptFilter</a></code></li>
3543 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
3546 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3547 <div class="directive-section"><h2><a name="RegisterHttpMethod" id="RegisterHttpMethod">RegisterHttpMethod</a> <a name="registerhttpmethod" id="registerhttpmethod">Directive</a></h2>
3548 <table class="directive">
3549 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Register non-standard HTTP methods</td></tr>
3550 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>RegisterHttpMethod <var>method</var> [<var>method</var> [...]]</code></td></tr>
3551 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3552 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3553 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3555 <p>HTTP Methods that are not conforming to the relvant RFCs are normally
3556 rejected by request processing in Apache HTTPD. To avoid this, modules
3557 can register non-standard HTTP methods they support.
3558 The <code class="directive">RegisterHttpMethod</code> allows to register such
3559 methods manually. This can be useful for if such methods are forwared
3560 for external processing, e.g. to a CGI script.</p>
3563 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3564 <div class="directive-section"><h2><a name="RLimitCPU" id="RLimitCPU">RLimitCPU</a> <a name="rlimitcpu" id="rlimitcpu">Directive</a></h2>
3565 <table class="directive">
3566 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the CPU consumption of processes launched
3567 by Apache httpd children</td></tr>
3568 <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>
3569 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3570 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3571 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3572 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3573 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3575 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3576 resource limit for all processes and the second parameter sets
3577 the maximum resource limit. Either parameter can be a number,
3578 or <code>max</code> to indicate to the server that the limit should
3579 be set to the maximum allowed by the operating system
3580 configuration. Raising the maximum resource limit requires that
3581 the server is running as <code>root</code>, or in the initial startup
3584 <p>This applies to processes forked off from Apache httpd children
3585 servicing requests, not the Apache httpd children themselves. This
3586 includes CGI scripts and SSI exec commands, but not any
3587 processes forked off from the Apache httpd parent such as piped
3590 <p>CPU resource limits are expressed in seconds per
3595 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3596 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3599 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3600 <div class="directive-section"><h2><a name="RLimitMEM" id="RLimitMEM">RLimitMEM</a> <a name="rlimitmem" id="rlimitmem">Directive</a></h2>
3601 <table class="directive">
3602 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the memory consumption of processes launched
3603 by Apache httpd children</td></tr>
3604 <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>
3605 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3606 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3607 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3608 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3609 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3611 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3612 resource limit for all processes and the second parameter sets
3613 the maximum resource limit. Either parameter can be a number,
3614 or <code>max</code> to indicate to the server that the limit should
3615 be set to the maximum allowed by the operating system
3616 configuration. Raising the maximum resource limit requires that
3617 the server is running as <code>root</code>, or in the initial startup
3620 <p>This applies to processes forked off from Apache httpd children
3621 servicing requests, not the Apache httpd children themselves. This
3622 includes CGI scripts and SSI exec commands, but not any
3623 processes forked off from the Apache httpd parent such as piped
3626 <p>Memory resource limits are expressed in bytes per
3631 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3632 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3635 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3636 <div class="directive-section"><h2><a name="RLimitNPROC" id="RLimitNPROC">RLimitNPROC</a> <a name="rlimitnproc" id="rlimitnproc">Directive</a></h2>
3637 <table class="directive">
3638 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of processes that can be launched by
3639 processes launched by Apache httpd children</td></tr>
3640 <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>
3641 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3642 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3643 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3644 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3645 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3647 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3648 resource limit for all processes and the second parameter sets
3649 the maximum resource limit. Either parameter can be a number,
3650 or <code>max</code> to indicate to the server that the limit
3651 should be set to the maximum allowed by the operating system
3652 configuration. Raising the maximum resource limit requires that
3653 the server is running as <code>root</code>, or in the initial startup
3656 <p>This applies to processes forked off from Apache httpd children
3657 servicing requests, not the Apache httpd children themselves. This
3658 includes CGI scripts and SSI exec commands, but not any
3659 processes forked off from the Apache httpd parent such as piped
3662 <p>Process limits control the number of processes per user.</p>
3664 <div class="note"><h3>Note</h3>
3665 <p>If CGI processes are <strong>not</strong> running
3666 under user ids other than the web server user id, this directive
3667 will limit the number of processes that the server itself can
3668 create. Evidence of this situation will be indicated by
3669 <strong><code>cannot fork</code></strong> messages in the
3670 <code>error_log</code>.</p>
3675 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3676 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3679 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3680 <div class="directive-section"><h2><a name="ScriptInterpreterSource" id="ScriptInterpreterSource">ScriptInterpreterSource</a> <a name="scriptinterpretersource" id="scriptinterpretersource">Directive</a></h2>
3681 <table class="directive">
3682 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
3684 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ScriptInterpreterSource Registry|Registry-Strict|Script</code></td></tr>
3685 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ScriptInterpreterSource Script</code></td></tr>
3686 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3687 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3688 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3689 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3690 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Win32 only;
3691 option <code>Registry-Strict</code> is available in Apache HTTP Server 2.0 and
3694 <p>This directive is used to control how Apache httpd finds the
3695 interpreter used to run CGI scripts. The default setting is
3696 <code>Script</code>. This causes Apache httpd to use the interpreter pointed to
3697 by the shebang line (first line, starting with <code>#!</code>) in the
3698 script. On Win32 systems this line usually looks like:</p>
3700 <pre class="prettyprint lang-perl">#!C:/Perl/bin/perl.exe</pre>
3703 <p>or, if <code>perl</code> is in the <code>PATH</code>, simply:</p>
3705 <pre class="prettyprint lang-perl">#!perl</pre>
3708 <p>Setting <code>ScriptInterpreterSource Registry</code> will
3709 cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
3710 searched using the script file extension (e.g., <code>.pl</code>) as a
3711 search key. The command defined by the registry subkey
3712 <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
3713 <code>Shell\Open\Command</code> is used to open the script file. If the
3714 registry keys cannot be found, Apache httpd falls back to the behavior of the
3715 <code>Script</code> option.</p>
3717 <div class="warning"><h3>Security</h3>
3718 <p>Be careful when using <code>ScriptInterpreterSource
3719 Registry</code> with <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>'ed directories, because
3720 Apache httpd will try to execute <strong>every</strong> file within this
3721 directory. The <code>Registry</code> setting may cause undesired
3722 program calls on files which are typically not executed. For
3723 example, the default open command on <code>.htm</code> files on
3724 most Windows systems will execute Microsoft Internet Explorer, so
3725 any HTTP request for an <code>.htm</code> file existing within the
3726 script directory would start the browser in the background on the
3727 server. This is a good way to crash your system within a minute or
3731 <p>The option <code>Registry-Strict</code> which is new in Apache HTTP Server
3732 2.0 does the same thing as <code>Registry</code> but uses only the
3733 subkey <code>Shell\ExecCGI\Command</code>. The
3734 <code>ExecCGI</code> key is not a common one. It must be
3735 configured manually in the windows registry and hence prevents
3736 accidental program calls on your system.</p>
3739 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3740 <div class="directive-section"><h2><a name="SeeRequestTail" id="SeeRequestTail">SeeRequestTail</a> <a name="seerequesttail" id="seerequesttail">Directive</a></h2>
3741 <table class="directive">
3742 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine if mod_status displays the first 63 characters
3743 of a request or the last 63, assuming the request itself is greater than
3745 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SeeRequestTail On|Off</code></td></tr>
3746 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SeeRequestTail Off</code></td></tr>
3747 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3748 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3749 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3750 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.2.7 and later.</td></tr>
3752 <p>mod_status with <code>ExtendedStatus On</code>
3753 displays the actual request being handled.
3754 For historical purposes, only 63 characters of the request
3755 are actually stored for display purposes. This directive
3756 controls whether the 1st 63 characters are stored (the previous
3757 behavior and the default) or if the last 63 characters are. This
3758 is only applicable, of course, if the length of the request is
3759 64 characters or greater.</p>
3761 <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:
3764 <table class="bordered">
3766 <th>Off (default)</th>
3767 <td>GET /disk1/storage/apache/htdocs/images/imagestore1/food/apples</td>
3771 <td>orage/apache/htdocs/images/imagestore1/food/apples.jpg HTTP/1.1</td>
3777 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3778 <div class="directive-section"><h2><a name="ServerAdmin" id="ServerAdmin">ServerAdmin</a> <a name="serveradmin" id="serveradmin">Directive</a></h2>
3779 <table class="directive">
3780 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Email address that the server includes in error
3781 messages sent to the client</td></tr>
3782 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAdmin <var>email-address</var>|<var>URL</var></code></td></tr>
3783 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3784 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3785 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3787 <p>The <code class="directive">ServerAdmin</code> sets the contact address
3788 that the server includes in any error messages it returns to the
3789 client. If the <code>httpd</code> doesn't recognize the supplied argument
3791 assumes, that it's an <var>email-address</var> and prepends it with
3792 <code>mailto:</code> in hyperlink targets. However, it's recommended to
3793 actually use an email address, since there are a lot of CGI scripts that
3794 make that assumption. If you want to use an URL, it should point to another
3795 server under your control. Otherwise users may not be able to contact you in
3798 <p>It may be worth setting up a dedicated address for this, e.g.</p>
3800 <pre class="prettyprint lang-config">ServerAdmin www-admin@foo.example.com</pre>
3802 <p>as users do not always mention that they are talking about the
3806 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3807 <div class="directive-section"><h2><a name="ServerAlias" id="ServerAlias">ServerAlias</a> <a name="serveralias" id="serveralias">Directive</a></h2>
3808 <table class="directive">
3809 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Alternate names for a host used when matching requests
3810 to name-virtual hosts</td></tr>
3811 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</code></td></tr>
3812 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
3813 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3814 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3816 <p>The <code class="directive">ServerAlias</code> directive sets the
3817 alternate names for a host, for use with <a href="../vhosts/name-based.html">name-based virtual hosts</a>. The
3818 <code class="directive">ServerAlias</code> may include wildcards, if appropriate.</p>
3820 <pre class="prettyprint lang-config">
3821 <VirtualHost *:80>
3822 ServerName server.example.com
3823 ServerAlias server server2.example.com server2
3824 ServerAlias *.example.com
3825 UseCanonicalName Off
3827 </VirtualHost>
3831 <p>Name-based virtual hosts for the best-matching set of <code class="directive"><a href="#virtualhost"><virtualhost></a></code>s are processed
3832 in the order they appear in the configuration. The first matching <code class="directive"><a href="#servername">ServerName</a></code> or <code class="directive"><a href="#serveralias">ServerAlias</a></code> is used, with no different precedence for wildcards
3833 (nor for ServerName vs. ServerAlias). </p>
3835 <p>The complete list of names in the <code class="directive">VirtualHost</code>
3836 directive are treated just like a (non wildcard)
3837 <code class="directive">ServerAlias</code>.</p>
3842 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3843 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
3846 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3847 <div class="directive-section"><h2><a name="ServerName" id="ServerName">ServerName</a> <a name="servername" id="servername">Directive</a></h2>
3848 <table class="directive">
3849 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hostname and port that the server uses to identify
3851 <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>
3852 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3853 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3854 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3856 <p>The <code class="directive">ServerName</code> directive sets the
3857 request scheme, hostname and
3858 port that the server uses to identify itself. This is used when
3859 creating redirection URLs.</p>
3861 <p>Additionally, <code class="directive">ServerName</code> is used (possibly
3862 in conjunction with <code class="directive">ServerAlias</code>) to uniquely
3863 identify a virtual host, when using <a href="../vhosts/name-based.html">name-based virtual hosts</a>.</p>
3865 <p>For example, if the name of the
3866 machine hosting the web server is <code>simple.example.com</code>,
3867 but the machine also has the DNS alias <code>www.example.com</code>
3868 and you wish the web server to be so identified, the following
3869 directive should be used:</p>
3871 <pre class="prettyprint lang-config">ServerName www.example.com</pre>
3874 <p>The <code class="directive">ServerName</code> directive
3875 may appear anywhere within the definition of a server. However,
3876 each appearance overrides the previous appearance (within that
3879 <p>If no <code class="directive">ServerName</code> is specified, then the
3880 server attempts to deduce the hostname by performing a reverse
3881 lookup on the IP address. If no port is specified in the
3882 <code class="directive">ServerName</code>, then the server will use the
3883 port from the incoming request. For optimal reliability and
3884 predictability, you should specify an explicit hostname and port
3885 using the <code class="directive">ServerName</code> directive.</p>
3887 <p>If you are using <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
3888 the <code class="directive">ServerName</code> inside a
3889 <code class="directive"><a href="#virtualhost"><VirtualHost></a></code>
3890 section specifies what hostname must appear in the request's
3891 <code>Host:</code> header to match this virtual host.</p>
3893 <p>Sometimes, the server runs behind a device that processes SSL,
3894 such as a reverse proxy, load balancer or SSL offload
3895 appliance. When this is the case, specify the
3896 <code>https://</code> scheme and the port number to which the
3897 clients connect in the <code class="directive">ServerName</code> directive
3898 to make sure that the server generates the correct
3899 self-referential URLs.
3902 <p>See the description of the
3903 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> and
3904 <code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code> directives for
3905 settings which determine whether self-referential URLs (e.g., by the
3906 <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> module) will refer to the
3907 specified port, or to the port number given in the client's request.
3910 <div class="warning">
3911 <p>Failure to set <code class="directive">ServerName</code> to a name that
3912 your server can resolve to an IP address will result in a startup
3913 warning. <code>httpd</code> will then use whatever hostname it can
3914 determine, using the system's <code>hostname</code> command. This
3915 will almost never be the hostname you actually want.</p>
3916 <div class="example"><p><code>
3917 httpd: Could not reliably determine the server's fully qualified domain name, using rocinante.local for ServerName
3924 <li><a href="../dns-caveats.html">Issues Regarding DNS and
3925 Apache HTTP Server</a></li>
3926 <li><a href="../vhosts/">Apache HTTP Server virtual host
3927 documentation</a></li>
3928 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3929 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
3930 <li><code class="directive"><a href="#serveralias">ServerAlias</a></code></li>
3933 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3934 <div class="directive-section"><h2><a name="ServerPath" id="ServerPath">ServerPath</a> <a name="serverpath" id="serverpath">Directive</a></h2>
3935 <table class="directive">
3936 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Legacy URL pathname for a name-based virtual host that
3937 is accessed by an incompatible browser</td></tr>
3938 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerPath <var>URL-path</var></code></td></tr>
3939 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
3940 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3941 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3943 <p>The <code class="directive">ServerPath</code> directive sets the legacy
3944 URL pathname for a host, for use with <a href="../vhosts/">name-based virtual hosts</a>.</p>
3948 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
3951 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3952 <div class="directive-section"><h2><a name="ServerRoot" id="ServerRoot">ServerRoot</a> <a name="serverroot" id="serverroot">Directive</a></h2>
3953 <table class="directive">
3954 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server installation</td></tr>
3955 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerRoot <var>directory-path</var></code></td></tr>
3956 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerRoot /usr/local/apache</code></td></tr>
3957 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3958 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3959 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3961 <p>The <code class="directive">ServerRoot</code> directive sets the
3962 directory in which the server lives. Typically it will contain the
3963 subdirectories <code>conf/</code> and <code>logs/</code>. Relative
3964 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
3965 relative to this directory.</p>
3967 <pre class="prettyprint lang-config">ServerRoot "/home/httpd"</pre>
3970 <p>The default location of <code class="directive">ServerRoot</code> may be
3971 modified by using the <code>--prefix</code> argument to
3972 <a href="../programs/configure.html"><code>configure</code></a>, and
3973 most third-party distributions of the server have a different
3974 default location from the one listed above.</p>
3979 <li><a href="../invoking.html">the <code>-d</code>
3980 option to <code>httpd</code></a></li>
3981 <li><a href="../misc/security_tips.html#serverroot">the
3982 security tips</a> for information on how to properly set
3983 permissions on the <code class="directive">ServerRoot</code></li>
3986 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3987 <div class="directive-section"><h2><a name="ServerSignature" id="ServerSignature">ServerSignature</a> <a name="serversignature" id="serversignature">Directive</a></h2>
3988 <table class="directive">
3989 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the footer on server-generated documents</td></tr>
3990 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerSignature On|Off|EMail</code></td></tr>
3991 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerSignature Off</code></td></tr>
3992 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3993 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3994 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3995 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3997 <p>The <code class="directive">ServerSignature</code> directive allows the
3998 configuration of a trailing footer line under server-generated
3999 documents (error messages, <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> ftp directory
4000 listings, <code class="module"><a href="../mod/mod_info.html">mod_info</a></code> output, ...). The reason why you
4001 would want to enable such a footer line is that in a chain of proxies,
4002 the user often has no possibility to tell which of the chained servers
4003 actually produced a returned error message.</p>
4005 <p>The <code>Off</code>
4006 setting, which is the default, suppresses the footer line (and is
4007 therefore compatible with the behavior of Apache-1.2 and
4008 below). The <code>On</code> setting simply adds a line with the
4009 server version number and <code class="directive"><a href="#servername">ServerName</a></code> of the serving virtual host,
4010 and the <code>EMail</code> setting additionally creates a
4011 "mailto:" reference to the <code class="directive"><a href="#serveradmin">ServerAdmin</a></code> of the referenced
4014 <p>After version 2.0.44, the details of the server version number
4015 presented are controlled by the <code class="directive"><a href="#servertokens">ServerTokens</a></code> directive.</p>
4019 <li><code class="directive"><a href="#servertokens">ServerTokens</a></code></li>
4022 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4023 <div class="directive-section"><h2><a name="ServerTokens" id="ServerTokens">ServerTokens</a> <a name="servertokens" id="servertokens">Directive</a></h2>
4024 <table class="directive">
4025 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the <code>Server</code> HTTP response
4027 <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>
4028 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerTokens Full</code></td></tr>
4029 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4030 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4031 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4033 <p>This directive controls whether <code>Server</code> response
4034 header field which is sent back to clients includes a
4035 description of the generic OS-type of the server as well as
4036 information about compiled-in modules.</p>
4039 <dt><code>ServerTokens Full</code> (or not specified)</dt>
4041 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4042 (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
4044 <dt><code>ServerTokens Prod[uctOnly]</code></dt>
4046 <dd>Server sends (<em>e.g.</em>): <code>Server:
4049 <dt><code>ServerTokens Major</code></dt>
4051 <dd>Server sends (<em>e.g.</em>): <code>Server:
4052 Apache/2</code></dd>
4054 <dt><code>ServerTokens Minor</code></dt>
4056 <dd>Server sends (<em>e.g.</em>): <code>Server:
4057 Apache/2.4</code></dd>
4059 <dt><code>ServerTokens Min[imal]</code></dt>
4061 <dd>Server sends (<em>e.g.</em>): <code>Server:
4062 Apache/2.4.2</code></dd>
4064 <dt><code>ServerTokens OS</code></dt>
4066 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4071 <p>This setting applies to the entire server, and cannot be
4072 enabled or disabled on a virtualhost-by-virtualhost basis.</p>
4074 <p>After version 2.0.44, this directive also controls the
4075 information presented by the <code class="directive"><a href="#serversignature">ServerSignature</a></code> directive.</p>
4077 <div class="note">Setting <code class="directive">ServerTokens</code> to less than
4078 <code>minimal</code> is not recommended because it makes it more
4079 difficult to debug interoperational problems. Also note that
4080 disabling the Server: header does nothing at all to make your
4081 server more secure; the idea of "security through obscurity"
4082 is a myth and leads to a false sense of safety.</div>
4087 <li><code class="directive"><a href="#serversignature">ServerSignature</a></code></li>
4090 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4091 <div class="directive-section"><h2><a name="SetHandler" id="SetHandler">SetHandler</a> <a name="sethandler" id="sethandler">Directive</a></h2>
4092 <table class="directive">
4093 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be processed by a
4095 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetHandler <var>handler-name</var>|None</code></td></tr>
4096 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4097 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4098 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4099 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4100 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Moved into the core in Apache httpd 2.0</td></tr>
4102 <p>When placed into an <code>.htaccess</code> file or a
4103 <code class="directive"><a href="#directory"><Directory></a></code> or
4104 <code class="directive"><a href="#location"><Location></a></code>
4105 section, this directive forces all matching files to be parsed
4106 through the <a href="../handler.html">handler</a> given by
4107 <var>handler-name</var>. For example, if you had a directory you
4108 wanted to be parsed entirely as imagemap rule files, regardless
4109 of extension, you might put the following into an
4110 <code>.htaccess</code> file in that directory:</p>
4112 <pre class="prettyprint lang-config">SetHandler imap-file</pre>
4115 <p>Another example: if you wanted to have the server display a
4116 status report whenever a URL of
4117 <code>http://servername/status</code> was called, you might put
4118 the following into <code>httpd.conf</code>:</p>
4120 <pre class="prettyprint lang-config">
4121 <Location "/status">
4122 SetHandler server-status
4127 <p>You could also use this directive to configure a particular
4128 handler for files with a particular file extension. For example:</p>
4130 <pre class="prettyprint lang-config">
4131 <FilesMatch \.php$>
4132 SetHandler application/x-httpd-php
4137 <p>You can override an earlier defined <code class="directive">SetHandler</code>
4138 directive by using the value <code>None</code>.</p>
4140 <div class="note"><h3>Note</h3>
4141 <p>Because <code class="directive">SetHandler</code> overrides default handlers,
4142 normal behavior such as handling of URLs ending in a slash (/) as
4143 directories or index files is suppressed.</p></div>
4147 <li><code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code></li>
4150 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4151 <div class="directive-section"><h2><a name="SetInputFilter" id="SetInputFilter">SetInputFilter</a> <a name="setinputfilter" id="setinputfilter">Directive</a></h2>
4152 <table class="directive">
4153 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process client requests and POST
4155 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetInputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4156 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4157 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4158 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4159 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4161 <p>The <code class="directive">SetInputFilter</code> directive sets the
4162 filter or filters which will process client requests and POST
4163 input when they are received by the server. This is in addition to
4164 any filters defined elsewhere, including the
4165 <code class="directive"><a href="../mod/mod_mime.html#addinputfilter">AddInputFilter</a></code>
4168 <p>If more than one filter is specified, they must be separated
4169 by semicolons in the order in which they should process the
4174 <li><a href="../filter.html">Filters</a> documentation</li>
4177 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4178 <div class="directive-section"><h2><a name="SetOutputFilter" id="SetOutputFilter">SetOutputFilter</a> <a name="setoutputfilter" id="setoutputfilter">Directive</a></h2>
4179 <table class="directive">
4180 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process responses from the
4182 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4183 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4184 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4185 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4186 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4188 <p>The <code class="directive">SetOutputFilter</code> directive sets the filters
4189 which will process responses from the server before they are
4190 sent to the client. This is in addition to any filters defined
4191 elsewhere, including the
4192 <code class="directive"><a href="../mod/mod_mime.html#addoutputfilter">AddOutputFilter</a></code>
4195 <p>For example, the following configuration will process all files
4196 in the <code>/www/data/</code> directory for server-side
4199 <pre class="prettyprint lang-config">
4200 <Directory "/www/data/">
4201 SetOutputFilter INCLUDES
4206 <p>If more than one filter is specified, they must be separated
4207 by semicolons in the order in which they should process the
4212 <li><a href="../filter.html">Filters</a> documentation</li>
4215 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4216 <div class="directive-section"><h2><a name="TimeOut" id="TimeOut">TimeOut</a> <a name="timeout" id="timeout">Directive</a></h2>
4217 <table class="directive">
4218 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for
4219 certain events before failing a request</td></tr>
4220 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TimeOut <var>seconds</var></code></td></tr>
4221 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TimeOut 60</code></td></tr>
4222 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4223 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4224 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4226 <p>The <code class="directive">TimeOut</code> directive defines the length
4227 of time Apache httpd will wait for I/O in various circumstances:</p>
4230 <li>When reading data from the client, the length of time to
4231 wait for a TCP packet to arrive if the read buffer is
4234 <li>When writing data to the client, the length of time to wait
4235 for an acknowledgement of a packet if the send buffer is
4238 <li>In <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>, the length of time to wait for
4239 output from a CGI script.</li>
4241 <li>In <code class="module"><a href="../mod/mod_ext_filter.html">mod_ext_filter</a></code>, the length of time to
4242 wait for output from a filtering process.</li>
4244 <li>In <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>, the default timeout value if
4245 <code class="directive"><a href="../mod/mod_proxy.html#proxytimeout">ProxyTimeout</a></code> is not
4251 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4252 <div class="directive-section"><h2><a name="TraceEnable" id="TraceEnable">TraceEnable</a> <a name="traceenable" id="traceenable">Directive</a></h2>
4253 <table class="directive">
4254 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines the behavior on <code>TRACE</code> requests</td></tr>
4255 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TraceEnable <var>[on|off|extended]</var></code></td></tr>
4256 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TraceEnable on</code></td></tr>
4257 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4258 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4259 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4260 <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>
4262 <p>This directive overrides the behavior of <code>TRACE</code> for both
4263 the core server and <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>. The default
4264 <code>TraceEnable on</code> permits <code>TRACE</code> requests per
4265 RFC 2616, which disallows any request body to accompany the request.
4266 <code>TraceEnable off</code> causes the core server and
4267 <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> to return a <code>405</code> (Method not
4268 allowed) error to the client.</p>
4270 <p>Finally, for testing and diagnostic purposes only, request
4271 bodies may be allowed using the non-compliant <code>TraceEnable
4272 extended</code> directive. The core (as an origin server) will
4273 restrict the request body to 64k (plus 8k for chunk headers if
4274 <code>Transfer-Encoding: chunked</code> is used). The core will
4275 reflect the full headers and all chunk headers with the response
4276 body. As a proxy server, the request body is not restricted to 64k.</p>
4278 <div class="note"><h3>Note</h3>
4279 <p>Despite claims to the contrary, <code>TRACE</code> is not
4280 a security vulnerability and there is no viable reason for
4281 it to be disabled. Doing so necessarily makes your server
4286 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4287 <div class="directive-section"><h2><a name="UnDefine" id="UnDefine">UnDefine</a> <a name="undefine" id="undefine">Directive</a></h2>
4288 <table class="directive">
4289 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Undefine the existence of a variable</td></tr>
4290 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UnDefine <var>parameter-name</var></code></td></tr>
4291 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4292 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4293 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4295 <p>Undoes the effect of a <code class="directive"><a href="#define">Define</a></code> or
4296 of passing a <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</p>
4297 <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
4298 <code>-D</code> arguments in any startup scripts.</p>
4301 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4302 <div class="directive-section"><h2><a name="UseCanonicalName" id="UseCanonicalName">UseCanonicalName</a> <a name="usecanonicalname" id="usecanonicalname">Directive</a></h2>
4303 <table class="directive">
4304 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own name and
4306 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalName On|Off|DNS</code></td></tr>
4307 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalName Off</code></td></tr>
4308 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4309 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4310 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4312 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4313 URL -- that is, a URL that refers back to the same server. With
4314 <code>UseCanonicalName On</code> Apache httpd will use the hostname and port
4315 specified in the <code class="directive"><a href="#servername">ServerName</a></code>
4316 directive to construct the canonical name for the server. This name
4317 is used in all self-referential URLs, and for the values of
4318 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>
4320 <p>With <code>UseCanonicalName Off</code> Apache httpd will form
4321 self-referential URLs using the hostname and port supplied by
4322 the client if any are supplied (otherwise it will use the
4323 canonical name, as defined above). These values are the same
4324 that are used to implement <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
4325 and are available with the same clients. The CGI variables
4326 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
4327 constructed from the client supplied values as well.</p>
4329 <p>An example where this may be useful is on an intranet server
4330 where you have users connecting to the machine using short
4331 names such as <code>www</code>. You'll notice that if the users
4332 type a shortname, and a URL which is a directory, such as
4333 <code>http://www/splat</code>, <em>without the trailing
4334 slash</em> then Apache httpd will redirect them to
4335 <code>http://www.example.com/splat/</code>. If you have
4336 authentication enabled, this will cause the user to have to
4337 authenticate twice (once for <code>www</code> and once again
4338 for <code>www.example.com</code> -- see <a href="http://wiki.apache.org/httpd/FAQ#Why_does_Apache_ask_for_my_password_twice_before_serving_a_file.3F">
4339 the FAQ on this subject for more information</a>). But if
4340 <code class="directive">UseCanonicalName</code> is set <code>Off</code>, then
4341 Apache httpd will redirect to <code>http://www/splat/</code>.</p>
4343 <p>There is a third option, <code>UseCanonicalName DNS</code>,
4344 which is intended for use with mass IP-based virtual hosting to
4345 support ancient clients that do not provide a
4346 <code>Host:</code> header. With this option Apache httpd does a
4347 reverse DNS lookup on the server IP address that the client
4348 connected to in order to work out self-referential URLs.</p>
4350 <div class="warning"><h3>Warning</h3>
4351 <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>
4352 they may be broken by this option. The client is essentially free
4353 to give whatever value they want as a hostname. But if the CGI is
4354 only using <code>SERVER_NAME</code> to construct self-referential URLs
4355 then it should be just fine.</p>
4360 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
4361 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4362 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4365 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4366 <div class="directive-section"><h2><a name="UseCanonicalPhysicalPort" id="UseCanonicalPhysicalPort">UseCanonicalPhysicalPort</a> <a name="usecanonicalphysicalport" id="usecanonicalphysicalport">Directive</a></h2>
4367 <table class="directive">
4368 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own port</td></tr>
4369 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalPhysicalPort On|Off</code></td></tr>
4370 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalPhysicalPort Off</code></td></tr>
4371 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4372 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4373 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4375 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4376 URL -- that is, a URL that refers back to the same server. With
4377 <code>UseCanonicalPhysicalPort On</code> Apache httpd will, when
4378 constructing the canonical port for the server to honor
4379 the <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> directive,
4380 provide the actual physical port number being used by this request
4381 as a potential port. With <code>UseCanonicalPhysicalPort Off</code>
4382 Apache httpd will not ever use the actual physical port number, instead
4383 relying on all configured information to construct a valid port number.</p>
4385 <div class="note"><h3>Note</h3>
4386 <p>The ordering of the lookup when the physical port is used is as
4389 <dt><code>UseCanonicalName On</code></dt>
4392 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4393 <li>Physical port</li>
4394 <li>Default port</li>
4397 <dt><code>UseCanonicalName Off | DNS</code></dt>
4400 <li>Parsed port from <code>Host:</code> header</li>
4401 <li>Physical port</li>
4402 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4403 <li>Default port</li>
4408 <p>With <code>UseCanonicalPhysicalPort Off</code>, the
4409 physical ports are removed from the ordering.</p>
4415 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
4416 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4417 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4420 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4421 <div class="directive-section"><h2><a name="VirtualHost" id="VirtualHost"><VirtualHost></a> <a name="virtualhost" id="virtualhost">Directive</a></h2>
4422 <table class="directive">
4423 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only to a specific
4424 hostname or IP address</td></tr>
4425 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><VirtualHost
4426 <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
4427 ...> ... </VirtualHost></code></td></tr>
4428 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4429 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4430 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4432 <p><code class="directive"><VirtualHost></code> and
4433 <code></VirtualHost></code> are used to enclose a group of
4434 directives that will apply only to a particular virtual host. Any
4435 directive that is allowed in a virtual host context may be
4436 used. When the server receives a request for a document on a
4437 particular virtual host, it uses the configuration directives
4438 enclosed in the <code class="directive"><VirtualHost></code>
4439 section. <var>Addr</var> can be any of the following, optionally followed by
4440 a colon and a port number (or *):</p>
4443 <li>The IP address of the virtual host;</li>
4445 <li>A fully qualified domain name for the IP address of the
4446 virtual host (not recommended);</li>
4448 <li>The character <code>*</code>, which acts as a wildcard and matches
4449 any IP address.</li>
4451 <li>The string <code>_default_</code>, which is an alias for <code>*</code></li>
4455 <pre class="prettyprint lang-config">
4456 <VirtualHost 10.1.2.3:80>
4457 ServerAdmin webmaster@host.example.com
4458 DocumentRoot /www/docs/host.example.com
4459 ServerName host.example.com
4460 ErrorLog logs/host.example.com-error_log
4461 TransferLog logs/host.example.com-access_log
4462 </VirtualHost>
4467 <p>IPv6 addresses must be specified in square brackets because
4468 the optional port number could not be determined otherwise. An
4469 IPv6 example is shown below:</p>
4471 <pre class="prettyprint lang-config">
4472 <VirtualHost [2001:db8::a00:20ff:fea7:ccea]:80>
4473 ServerAdmin webmaster@host.example.com
4474 DocumentRoot /www/docs/host.example.com
4475 ServerName host.example.com
4476 ErrorLog logs/host.example.com-error_log
4477 TransferLog logs/host.example.com-access_log
4478 </VirtualHost>
4482 <p>Each Virtual Host must correspond to a different IP address,
4483 different port number or a different host name for the server,
4484 in the former case the server machine must be configured to
4485 accept IP packets for multiple addresses. (If the machine does
4486 not have multiple network interfaces, then this can be
4487 accomplished with the <code>ifconfig alias</code> command -- if
4488 your OS supports it).</p>
4490 <div class="note"><h3>Note</h3>
4491 <p>The use of <code class="directive"><VirtualHost></code> does
4492 <strong>not</strong> affect what addresses Apache httpd listens on. You
4493 may need to ensure that Apache httpd is listening on the correct addresses
4494 using <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>.</p>
4497 <p>A <code class="directive"><a href="#servername">ServerName</a></code> should be
4498 specified inside each <code class="directive"><VirtualHost></code> block. If it is absent, the
4499 <code class="directive"><a href="#servername">ServerName</a></code> from the "main"
4500 server configuration will be inherited.</p>
4502 <p>When a request is received, the server first maps it to the best matching
4503 <code class="directive"><VirtualHost></code> based on the local
4504 IP address and port combination only. Non-wildcards have a higher
4505 precedence. If no match based on IP and port occurs at all, the
4506 "main" server configuration is used.</p>
4508 <p>If multiple virtual hosts contain the best matching IP address and port,
4509 the server selects from these virtual hosts the best match based on the
4510 requested hostname. If no matching name-based virtual host is found,
4511 then the first listed virtual host that matched the IP address will be
4512 used. As a consequence, the first listed virtual host for a given IP address
4513 and port combination is default virtual host for that IP and port
4516 <div class="warning"><h3>Security</h3>
4517 <p>See the <a href="../misc/security_tips.html">security tips</a>
4518 document for details on why your security could be compromised if the
4519 directory where log files are stored is writable by anyone other
4520 than the user that starts the server.</p>
4525 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4526 <li><a href="../dns-caveats.html">Issues Regarding DNS and
4527 Apache HTTP Server</a></li>
4528 <li><a href="../bind.html">Setting
4529 which addresses and ports Apache HTTP Server uses</a></li>
4530 <li><a href="../sections.html">How <Directory>, <Location>
4531 and <Files> sections work</a> for an explanation of how these
4532 different sections are combined when a request is received</li>
4536 <div class="bottomlang">
4537 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
4538 <a href="../en/mod/core.html" title="English"> en </a> |
4539 <a href="../es/mod/core.html" hreflang="es" rel="alternate" title="Español"> es </a> |
4540 <a href="../fr/mod/core.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
4541 <a href="../ja/mod/core.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
4542 <a href="../tr/mod/core.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p>
4543 </div><div class="top"><a href="#page-header"><img src="../images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Comments</a></h2><div class="warning"><strong>Notice:</strong><br />This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed again by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Freenode, or sent to our <a href="http://httpd.apache.org/lists.html">mailing lists</a>.</div>
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4561 <p class="apache">Copyright 2012 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>
4562 <p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div><script type="text/javascript"><!--//--><
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