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10 <title>core - Apache HTTP Server Version 2.5</title>
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20 <p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/quickreference.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p>
21 <p class="apache">Apache HTTP Server Version 2.5</p>
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25 <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>
26 <div id="page-content">
27 <div id="preamble"><h1>Apache Core Features</h1>
29 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
30 <a href="../en/mod/core.html" title="English"> en </a> |
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36 <table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Core Apache HTTP Server features that are always
38 <tr><th><a href="module-dict.html#Status">Status:</a></th><td>Core</td></tr></table>
40 <div id="quickview"><h3 class="directives">Directives</h3>
42 <li><img alt="" src="../images/down.gif" /> <a href="#acceptfilter">AcceptFilter</a></li>
43 <li><img alt="" src="../images/down.gif" /> <a href="#acceptpathinfo">AcceptPathInfo</a></li>
44 <li><img alt="" src="../images/down.gif" /> <a href="#accessfilename">AccessFileName</a></li>
45 <li><img alt="" src="../images/down.gif" /> <a href="#adddefaultcharset">AddDefaultCharset</a></li>
46 <li><img alt="" src="../images/down.gif" /> <a href="#allowencodedslashes">AllowEncodedSlashes</a></li>
47 <li><img alt="" src="../images/down.gif" /> <a href="#allowoverride">AllowOverride</a></li>
48 <li><img alt="" src="../images/down.gif" /> <a href="#allowoverridelist">AllowOverrideList</a></li>
49 <li><img alt="" src="../images/down.gif" /> <a href="#asyncfilter">AsyncFilter</a></li>
50 <li><img alt="" src="../images/down.gif" /> <a href="#cgimapextension">CGIMapExtension</a></li>
51 <li><img alt="" src="../images/down.gif" /> <a href="#cgipassauth">CGIPassAuth</a></li>
52 <li><img alt="" src="../images/down.gif" /> <a href="#contentdigest">ContentDigest</a></li>
53 <li><img alt="" src="../images/down.gif" /> <a href="#defaultruntimedir">DefaultRuntimeDir</a></li>
54 <li><img alt="" src="../images/down.gif" /> <a href="#defaulttype">DefaultType</a></li>
55 <li><img alt="" src="../images/down.gif" /> <a href="#define">Define</a></li>
56 <li><img alt="" src="../images/down.gif" /> <a href="#directory"><Directory></a></li>
57 <li><img alt="" src="../images/down.gif" /> <a href="#directorymatch"><DirectoryMatch></a></li>
58 <li><img alt="" src="../images/down.gif" /> <a href="#documentroot">DocumentRoot</a></li>
59 <li><img alt="" src="../images/down.gif" /> <a href="#else"><Else></a></li>
60 <li><img alt="" src="../images/down.gif" /> <a href="#elseif"><ElseIf></a></li>
61 <li><img alt="" src="../images/down.gif" /> <a href="#enablemmap">EnableMMAP</a></li>
62 <li><img alt="" src="../images/down.gif" /> <a href="#enablesendfile">EnableSendfile</a></li>
63 <li><img alt="" src="../images/down.gif" /> <a href="#error">Error</a></li>
64 <li><img alt="" src="../images/down.gif" /> <a href="#errordocument">ErrorDocument</a></li>
65 <li><img alt="" src="../images/down.gif" /> <a href="#errorlog">ErrorLog</a></li>
66 <li><img alt="" src="../images/down.gif" /> <a href="#errorlogformat">ErrorLogFormat</a></li>
67 <li><img alt="" src="../images/down.gif" /> <a href="#extendedstatus">ExtendedStatus</a></li>
68 <li><img alt="" src="../images/down.gif" /> <a href="#fileetag">FileETag</a></li>
69 <li><img alt="" src="../images/down.gif" /> <a href="#files"><Files></a></li>
70 <li><img alt="" src="../images/down.gif" /> <a href="#filesmatch"><FilesMatch></a></li>
71 <li><img alt="" src="../images/down.gif" /> <a href="#forcetype">ForceType</a></li>
72 <li><img alt="" src="../images/down.gif" /> <a href="#gprofdir">GprofDir</a></li>
73 <li><img alt="" src="../images/down.gif" /> <a href="#hostnamelookups">HostnameLookups</a></li>
74 <li><img alt="" src="../images/down.gif" /> <a href="#if"><If></a></li>
75 <li><img alt="" src="../images/down.gif" /> <a href="#ifdefine"><IfDefine></a></li>
76 <li><img alt="" src="../images/down.gif" /> <a href="#ifmodule"><IfModule></a></li>
77 <li><img alt="" src="../images/down.gif" /> <a href="#include">Include</a></li>
78 <li><img alt="" src="../images/down.gif" /> <a href="#includeoptional">IncludeOptional</a></li>
79 <li><img alt="" src="../images/down.gif" /> <a href="#keepalive">KeepAlive</a></li>
80 <li><img alt="" src="../images/down.gif" /> <a href="#keepalivetimeout">KeepAliveTimeout</a></li>
81 <li><img alt="" src="../images/down.gif" /> <a href="#limit"><Limit></a></li>
82 <li><img alt="" src="../images/down.gif" /> <a href="#limitexcept"><LimitExcept></a></li>
83 <li><img alt="" src="../images/down.gif" /> <a href="#limitinternalrecursion">LimitInternalRecursion</a></li>
84 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestbody">LimitRequestBody</a></li>
85 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfields">LimitRequestFields</a></li>
86 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfieldsize">LimitRequestFieldSize</a></li>
87 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestline">LimitRequestLine</a></li>
88 <li><img alt="" src="../images/down.gif" /> <a href="#limitxmlrequestbody">LimitXMLRequestBody</a></li>
89 <li><img alt="" src="../images/down.gif" /> <a href="#location"><Location></a></li>
90 <li><img alt="" src="../images/down.gif" /> <a href="#locationmatch"><LocationMatch></a></li>
91 <li><img alt="" src="../images/down.gif" /> <a href="#loglevel">LogLevel</a></li>
92 <li><img alt="" src="../images/down.gif" /> <a href="#logleveloverride">LogLevelOverride</a></li>
93 <li><img alt="" src="../images/down.gif" /> <a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></li>
94 <li><img alt="" src="../images/down.gif" /> <a href="#maxrangeoverlaps">MaxRangeOverlaps</a></li>
95 <li><img alt="" src="../images/down.gif" /> <a href="#maxrangereversals">MaxRangeReversals</a></li>
96 <li><img alt="" src="../images/down.gif" /> <a href="#maxranges">MaxRanges</a></li>
97 <li><img alt="" src="../images/down.gif" /> <a href="#mergetrailers">MergeTrailers</a></li>
98 <li><img alt="" src="../images/down.gif" /> <a href="#mutex">Mutex</a></li>
99 <li><img alt="" src="../images/down.gif" /> <a href="#namevirtualhost">NameVirtualHost</a></li>
100 <li><img alt="" src="../images/down.gif" /> <a href="#options">Options</a></li>
101 <li><img alt="" src="../images/down.gif" /> <a href="#protocol">Protocol</a></li>
102 <li><img alt="" src="../images/down.gif" /> <a href="#protocols">Protocols</a></li>
103 <li><img alt="" src="../images/down.gif" /> <a href="#protocolshonororder">ProtocolsHonorOrder</a></li>
104 <li><img alt="" src="../images/down.gif" /> <a href="#registerhttpmethod">RegisterHttpMethod</a></li>
105 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitcpu">RLimitCPU</a></li>
106 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitmem">RLimitMEM</a></li>
107 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitnproc">RLimitNPROC</a></li>
108 <li><img alt="" src="../images/down.gif" /> <a href="#scriptinterpretersource">ScriptInterpreterSource</a></li>
109 <li><img alt="" src="../images/down.gif" /> <a href="#seerequesttail">SeeRequestTail</a></li>
110 <li><img alt="" src="../images/down.gif" /> <a href="#serveradmin">ServerAdmin</a></li>
111 <li><img alt="" src="../images/down.gif" /> <a href="#serveralias">ServerAlias</a></li>
112 <li><img alt="" src="../images/down.gif" /> <a href="#servername">ServerName</a></li>
113 <li><img alt="" src="../images/down.gif" /> <a href="#serverpath">ServerPath</a></li>
114 <li><img alt="" src="../images/down.gif" /> <a href="#serverroot">ServerRoot</a></li>
115 <li><img alt="" src="../images/down.gif" /> <a href="#serversignature">ServerSignature</a></li>
116 <li><img alt="" src="../images/down.gif" /> <a href="#servertokens">ServerTokens</a></li>
117 <li><img alt="" src="../images/down.gif" /> <a href="#sethandler">SetHandler</a></li>
118 <li><img alt="" src="../images/down.gif" /> <a href="#setinputfilter">SetInputFilter</a></li>
119 <li><img alt="" src="../images/down.gif" /> <a href="#setoutputfilter">SetOutputFilter</a></li>
120 <li><img alt="" src="../images/down.gif" /> <a href="#timeout">TimeOut</a></li>
121 <li><img alt="" src="../images/down.gif" /> <a href="#traceenable">TraceEnable</a></li>
122 <li><img alt="" src="../images/down.gif" /> <a href="#undefine">UnDefine</a></li>
123 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalname">UseCanonicalName</a></li>
124 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></li>
125 <li><img alt="" src="../images/down.gif" /> <a href="#virtualhost"><VirtualHost></a></li>
126 <li><img alt="" src="../images/down.gif" /> <a href="#warning">Warning</a></li>
128 <ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div>
130 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
131 <div class="directive-section"><h2><a name="AcceptFilter" id="AcceptFilter">AcceptFilter</a> <a name="acceptfilter" id="acceptfilter">Directive</a></h2>
132 <table class="directive">
133 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures optimizations for a Protocol's Listener Sockets</td></tr>
134 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptFilter <var>protocol</var> <var>accept_filter</var></code></td></tr>
135 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
136 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
137 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
139 <p>This directive enables operating system specific optimizations for a
140 listening socket by the <code class="directive">Protocol</code> type.
141 The basic premise is for the kernel to not send a socket to the server
142 process until either data is received or an entire HTTP Request is buffered.
143 Only <a href="http://www.freebsd.org/cgi/man.cgi?query=accept_filter&sektion=9">
144 FreeBSD's Accept Filters</a>, Linux's more primitive
145 <code>TCP_DEFER_ACCEPT</code>, and Windows' optimized AcceptEx()
146 are currently supported.</p>
148 <p>Using <code>none</code> for an argument will disable any accept filters
149 for that protocol. This is useful for protocols that require a server
150 send data first, such as <code>ftp:</code> or <code>nntp</code>:</p>
151 <pre class="prettyprint lang-config">AcceptFilter nntp none</pre>
154 <p>The default protocol names are <code>https</code> for port 443
155 and <code>http</code> for all other ports. To specify that another
156 protocol is being used with a listening port, add the <var>protocol</var>
157 argument to the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>
160 <p>The default values on FreeBSD are:</p>
161 <pre class="prettyprint lang-config">AcceptFilter http httpready
162 AcceptFilter https dataready</pre>
165 <p>The <code>httpready</code> accept filter buffers entire HTTP requests at
166 the kernel level. Once an entire request is received, the kernel then
167 sends it to the server. See the
168 <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_http&sektion=9">
169 accf_http(9)</a> man page for more details. Since HTTPS requests are
170 encrypted, only the <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_data&sektion=9">
171 accf_data(9)</a> filter is used.</p>
173 <p>The default values on Linux are:</p>
174 <pre class="prettyprint lang-config">AcceptFilter http data
175 AcceptFilter https data</pre>
178 <p>Linux's <code>TCP_DEFER_ACCEPT</code> does not support buffering http
179 requests. Any value besides <code>none</code> will enable
180 <code>TCP_DEFER_ACCEPT</code> on that listener. For more details
182 <a href="http://homepages.cwi.nl/~aeb/linux/man2html/man7/tcp.7.html">
183 tcp(7)</a> man page.</p>
185 <p>The default values on Windows are:</p>
186 <pre class="prettyprint lang-config">AcceptFilter http data
187 AcceptFilter https data</pre>
190 <p>Window's mpm_winnt interprets the AcceptFilter to toggle the AcceptEx()
191 API, and does not support http protocol buffering. There are two values
192 which utilize the Windows AcceptEx() API and will recycle network
193 sockets between connections. <code>data</code> waits until data has
194 been transmitted as documented above, and the initial data buffer and
195 network endpoint addresses are all retrieved from the single AcceptEx()
196 invocation. <code>connect</code> will use the AcceptEx() API, also
197 retrieve the network endpoint addresses, but like <code>none</code>
198 the <code>connect</code> option does not wait for the initial data
201 <p>On Windows, <code>none</code> uses accept() rather than AcceptEx()
202 and will not recycle sockets between connections. This is useful for
203 network adapters with broken driver support, as well as some virtual
204 network providers such as vpn drivers, or spam, virus or spyware
210 <li><code class="directive"><a href="#protocol">Protocol</a></code></li>
213 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
214 <div class="directive-section"><h2><a name="AcceptPathInfo" id="AcceptPathInfo">AcceptPathInfo</a> <a name="acceptpathinfo" id="acceptpathinfo">Directive</a></h2>
215 <table class="directive">
216 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Resources accept trailing pathname information</td></tr>
217 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptPathInfo On|Off|Default</code></td></tr>
218 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AcceptPathInfo Default</code></td></tr>
219 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
220 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
221 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
222 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
225 <p>This directive controls whether requests that contain trailing
226 pathname information that follows an actual filename (or
227 non-existent file in an existing directory) will be accepted or
228 rejected. The trailing pathname information can be made
229 available to scripts in the <code>PATH_INFO</code> environment
232 <p>For example, assume the location <code>/test/</code> points to
233 a directory that contains only the single file
234 <code>here.html</code>. Then requests for
235 <code>/test/here.html/more</code> and
236 <code>/test/nothere.html/more</code> both collect
237 <code>/more</code> as <code>PATH_INFO</code>.</p>
239 <p>The three possible arguments for the
240 <code class="directive">AcceptPathInfo</code> directive are:</p>
242 <dt><code>Off</code></dt><dd>A request will only be accepted if it
243 maps to a literal path that exists. Therefore a request with
244 trailing pathname information after the true filename such as
245 <code>/test/here.html/more</code> in the above example will return
246 a 404 NOT FOUND error.</dd>
248 <dt><code>On</code></dt><dd>A request will be accepted if a
249 leading path component maps to a file that exists. The above
250 example <code>/test/here.html/more</code> will be accepted if
251 <code>/test/here.html</code> maps to a valid file.</dd>
253 <dt><code>Default</code></dt><dd>The treatment of requests with
254 trailing pathname information is determined by the <a href="../handler.html">handler</a> responsible for the request.
255 The core handler for normal files defaults to rejecting
256 <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
257 <code>PATH_INFO</code> by default.</dd>
260 <p>The primary purpose of the <code>AcceptPathInfo</code>
261 directive is to allow you to override the handler's choice of
262 accepting or rejecting <code>PATH_INFO</code>. This override is required,
263 for example, when you use a <a href="../filter.html">filter</a>, such
264 as <a href="mod_include.html">INCLUDES</a>, to generate content
265 based on <code>PATH_INFO</code>. The core handler would usually reject
266 the request, so you can use the following configuration to enable
269 <pre class="prettyprint lang-config"><Files "mypaths.shtml">
271 SetOutputFilter INCLUDES
278 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
279 <div class="directive-section"><h2><a name="AccessFileName" id="AccessFileName">AccessFileName</a> <a name="accessfilename" id="accessfilename">Directive</a></h2>
280 <table class="directive">
281 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Name of the distributed configuration file</td></tr>
282 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AccessFileName <var>filename</var> [<var>filename</var>] ...</code></td></tr>
283 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AccessFileName .htaccess</code></td></tr>
284 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
285 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
286 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
288 <p>While processing a request, the server looks for
289 the first existing configuration file from this list of names in
290 every directory of the path to the document, if distributed
291 configuration files are <a href="#allowoverride">enabled for that
292 directory</a>. For example:</p>
294 <pre class="prettyprint lang-config">AccessFileName .acl</pre>
297 <p>Before returning the document
298 <code>/usr/local/web/index.html</code>, the server will read
299 <code>/.acl</code>, <code>/usr/.acl</code>,
300 <code>/usr/local/.acl</code> and <code>/usr/local/web/.acl</code>
301 for directives unless they have been disabled with:</p>
303 <pre class="prettyprint lang-config"><Directory "/">
305 </Directory></pre>
310 <li><code class="directive"><a href="#allowoverride">AllowOverride</a></code></li>
311 <li><a href="../configuring.html">Configuration Files</a></li>
312 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
315 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
316 <div class="directive-section"><h2><a name="AddDefaultCharset" id="AddDefaultCharset">AddDefaultCharset</a> <a name="adddefaultcharset" id="adddefaultcharset">Directive</a></h2>
317 <table class="directive">
318 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Default charset parameter to be added when a response
319 content-type is <code>text/plain</code> or <code>text/html</code></td></tr>
320 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AddDefaultCharset On|Off|<var>charset</var></code></td></tr>
321 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AddDefaultCharset Off</code></td></tr>
322 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
323 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
324 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
325 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
327 <p>This directive specifies a default value for the media type
328 charset parameter (the name of a character encoding) to be added
329 to a response if and only if the response's content-type is either
330 <code>text/plain</code> or <code>text/html</code>. This should override
331 any charset specified in the body of the response via a <code>META</code>
332 element, though the exact behavior is often dependent on the user's client
333 configuration. A setting of <code>AddDefaultCharset Off</code>
334 disables this functionality. <code>AddDefaultCharset On</code> enables
335 a default charset of <code>iso-8859-1</code>. Any other value is assumed
336 to be the <var>charset</var> to be used, which should be one of the
337 <a href="http://www.iana.org/assignments/character-sets">IANA registered
338 charset values</a> for use in Internet media types (MIME types).
341 <pre class="prettyprint lang-config">AddDefaultCharset utf-8</pre>
344 <p><code class="directive">AddDefaultCharset</code> should only be used when all
345 of the text resources to which it applies are known to be in that
346 character encoding and it is too inconvenient to label their charset
347 individually. One such example is to add the charset parameter
348 to resources containing generated content, such as legacy CGI
349 scripts, that might be vulnerable to cross-site scripting attacks
350 due to user-provided data being included in the output. Note, however,
351 that a better solution is to just fix (or delete) those scripts, since
352 setting a default charset does not protect users that have enabled
353 the "auto-detect character encoding" feature on their browser.</p>
357 <li><code class="directive"><a href="../mod/mod_mime.html#addcharset">AddCharset</a></code></li>
360 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
361 <div class="directive-section"><h2><a name="AllowEncodedSlashes" id="AllowEncodedSlashes">AllowEncodedSlashes</a> <a name="allowencodedslashes" id="allowencodedslashes">Directive</a></h2>
362 <table class="directive">
363 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines whether encoded path separators in URLs are allowed to
364 be passed through</td></tr>
365 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowEncodedSlashes On|Off|NoDecode</code></td></tr>
366 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowEncodedSlashes Off</code></td></tr>
367 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
368 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
369 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
370 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>
371 NoDecode option available in 2.3.12 and later.</td></tr>
373 <p>The <code class="directive">AllowEncodedSlashes</code> directive allows URLs
374 which contain encoded path separators (<code>%2F</code> for <code>/</code>
375 and additionally <code>%5C</code> for <code>\</code> on accordant systems)
376 to be used in the path info.</p>
378 <p>With the default value, <code>Off</code>, such URLs are refused
379 with a 404 (Not found) error.</p>
381 <p>With the value <code>On</code>, such URLs are accepted, and encoded
382 slashes are decoded like all other encoded characters.</p>
384 <p>With the value <code>NoDecode</code>, such URLs are accepted, but
385 encoded slashes are not decoded but left in their encoded state.</p>
387 <p>Turning <code class="directive">AllowEncodedSlashes</code> <code>On</code> is
388 mostly useful when used in conjunction with <code>PATH_INFO</code>.</p>
390 <div class="note"><h3>Note</h3>
391 <p>If encoded slashes are needed in path info, use of <code>NoDecode</code> is
392 strongly recommended as a security measure. Allowing slashes
393 to be decoded could potentially allow unsafe paths.</p>
398 <li><code class="directive"><a href="#acceptpathinfo">AcceptPathInfo</a></code></li>
401 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
402 <div class="directive-section"><h2><a name="AllowOverride" id="AllowOverride">AllowOverride</a> <a name="allowoverride" id="allowoverride">Directive</a></h2>
403 <table class="directive">
404 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Types of directives that are allowed in
405 <code>.htaccess</code> files</td></tr>
406 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowOverride All|None|<var>directive-type</var>
407 [<var>directive-type</var>] ...</code></td></tr>
408 <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>
409 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
410 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
411 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
413 <p>When the server finds an <code>.htaccess</code> file (as
414 specified by <code class="directive"><a href="#accessfilename">AccessFileName</a></code>),
415 it needs to know which directives declared in that file can override
416 earlier configuration directives.</p>
418 <div class="note"><h3>Only available in <Directory> sections</h3>
419 <code class="directive">AllowOverride</code> is valid only in
420 <code class="directive"><a href="#directory"><Directory></a></code>
421 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
422 <code class="directive"><a href="#files"><Files></a></code> sections.
425 <p>When this directive is set to <code>None</code> and <code class="directive"><a href="#allowoverridelist">AllowOverrideList</a></code> is set to
426 <code>None</code>, <a href="#accessfilename">.htaccess</a> files are
427 completely ignored. In this case, the server will not even attempt
428 to read <code>.htaccess</code> files in the filesystem.</p>
430 <p>When this directive is set to <code>All</code>, then any
431 directive which has the .htaccess <a href="directive-dict.html#Context">Context</a> is allowed in
432 <code>.htaccess</code> files.</p>
434 <p>The <var>directive-type</var> can be one of the following
435 groupings of directives.</p>
442 Allow use of the authorization directives (<code class="directive"><a href="../mod/mod_authz_dbm.html#authdbmgroupfile">AuthDBMGroupFile</a></code>,
443 <code class="directive"><a href="../mod/mod_authn_dbm.html#authdbmuserfile">AuthDBMUserFile</a></code>,
444 <code class="directive"><a href="../mod/mod_authz_groupfile.html#authgroupfile">AuthGroupFile</a></code>,
445 <code class="directive"><a href="../mod/mod_authn_core.html#authname">AuthName</a></code>,
446 <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>
451 Allow use of the directives controlling document types
452 (<code class="directive"><a href="#errordocument">ErrorDocument</a></code>,
453 <code class="directive"><a href="#forcetype">ForceType</a></code>,
454 <code class="directive"><a href="../mod/mod_negotiation.html#languagepriority">LanguagePriority</a></code>,
455 <code class="directive"><a href="#sethandler">SetHandler</a></code>,
456 <code class="directive"><a href="#setinputfilter">SetInputFilter</a></code>,
457 <code class="directive"><a href="#setoutputfilter">SetOutputFilter</a></code>, and
458 <code class="module"><a href="../mod/mod_mime.html">mod_mime</a></code> Add* and Remove* directives),
459 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>),
460 <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>),
461 <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
462 <code class="directive"><a href="../mod/mod_actions.html#action">Action</a></code> from
463 <code class="module"><a href="../mod/mod_actions.html">mod_actions</a></code>.
469 Allow use of the directives controlling directory indexing
470 (<code class="directive"><a href="../mod/mod_autoindex.html#adddescription">AddDescription</a></code>,
471 <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>,
472 <code class="directive"><a href="../mod/mod_autoindex.html#addiconbytype">AddIconByType</a></code>,
473 <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>,
479 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>
484 <dt>Nonfatal=[Override|Unknown|All]</dt>
487 Allow use of AllowOverride option to treat syntax errors in
488 .htaccess as nonfatal. Instead of causing an Internal Server
489 Error, disallowed or unrecognised directives will be ignored
490 and a warning logged:
492 <li><strong>Nonfatal=Override</strong> treats directives
493 forbidden by AllowOverride as nonfatal.</li>
494 <li><strong>Nonfatal=Unknown</strong> treats unknown directives
495 as nonfatal. This covers typos and directives implemented
496 by a module that's not present.</li>
497 <li><strong>Nonfatal=All</strong> treats both the above as nonfatal.</li>
499 <p>Note that a syntax error in a valid directive will still cause
500 an internal server error.</p>
501 <div class="warning"><h3>Security</h3>
502 Nonfatal errors may have security implications for .htaccess users.
503 For example, if AllowOverride disallows AuthConfig, users'
504 configuration designed to restrict access to a site will be disabled.
508 <dt>Options[=<var>Option</var>,...]</dt>
511 Allow use of the directives controlling specific directory
512 features (<code class="directive"><a href="#options">Options</a></code> and
513 <code class="directive"><a href="../mod/mod_include.html#xbithack">XBitHack</a></code>).
514 An equal sign may be given followed by a comma-separated list, without
515 spaces, of options that may be set using the <code class="directive"><a href="#options">Options</a></code> command.
517 <div class="note"><h3>Implicit disabling of Options</h3>
518 <p>Even though the list of options that may be used in .htaccess files
519 can be limited with this directive, as long as any <code class="directive"><a href="#options">Options</a></code> directive is allowed any
520 other inherited option can be disabled by using the non-relative
521 syntax. In other words, this mechanism cannot force a specific option
522 to remain <em>set</em> while allowing any others to be set.
525 <div class="example"><p><code>
526 AllowOverride Options=Indexes,MultiViews
533 <pre class="prettyprint lang-config">AllowOverride AuthConfig Indexes</pre>
536 <p>In the example above, all directives that are neither in the group
537 <code>AuthConfig</code> nor <code>Indexes</code> cause an internal
540 <div class="note"><p>For security and performance reasons, do not set
541 <code>AllowOverride</code> to anything other than <code>None</code>
542 in your <code><Directory "/"></code> block. Instead, find (or
543 create) the <code><Directory></code> block that refers to the
544 directory where you're actually planning to place a
545 <code>.htaccess</code> file.</p>
550 <li><code class="directive"><a href="#accessfilename">AccessFileName</a></code></li>
551 <li><code class="directive"><a href="#allowoverridelist">AllowOverrideList</a></code></li>
552 <li><a href="../configuring.html">Configuration Files</a></li>
553 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
556 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
557 <div class="directive-section"><h2><a name="AllowOverrideList" id="AllowOverrideList">AllowOverrideList</a> <a name="allowoverridelist" id="allowoverridelist">Directive</a></h2>
558 <table class="directive">
559 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Individual directives that are allowed in
560 <code>.htaccess</code> files</td></tr>
561 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowOverrideList None|<var>directive</var>
562 [<var>directive-type</var>] ...</code></td></tr>
563 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowOverrideList None</code></td></tr>
564 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
565 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
566 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
568 <p>When the server finds an <code>.htaccess</code> file (as
569 specified by <code class="directive"><a href="#accessfilename">AccessFileName</a></code>),
570 it needs to know which directives declared in that file can override
571 earlier configuration directives.</p>
573 <div class="note"><h3>Only available in <Directory> sections</h3>
574 <code class="directive">AllowOverrideList</code> is valid only in
575 <code class="directive"><a href="#directory"><Directory></a></code>
576 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
577 <code class="directive"><a href="#files"><Files></a></code> sections.
580 <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>,
581 then <a href="#accessfilename">.htaccess</a> files are completely
582 ignored. In this case, the server will not even attempt to read
583 <code>.htaccess</code> files in the filesystem.</p>
587 <pre class="prettyprint lang-config">AllowOverride None
588 AllowOverrideList Redirect RedirectMatch</pre>
591 <p>In the example above, only the <code>Redirect</code> and
592 <code>RedirectMatch</code> directives are allowed. All others will
593 cause an internal server error.</p>
597 <pre class="prettyprint lang-config">AllowOverride AuthConfig
598 AllowOverrideList CookieTracking CookieName</pre>
601 <p>In the example above, <code class="directive"><a href="#allowoverride">AllowOverride
602 </a></code> grants permission to the <code>AuthConfig</code>
603 directive grouping and <code class="directive">AllowOverrideList</code> grants
604 permission to only two directives from the <code>FileInfo</code> directive
605 grouping. All others will cause an internal server error.</p>
609 <li><code class="directive"><a href="#accessfilename">AccessFileName</a></code></li>
610 <li><code class="directive"><a href="#allowoverride">AllowOverride</a></code></li>
611 <li><a href="../configuring.html">Configuration Files</a></li>
612 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
615 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
616 <div class="directive-section"><h2><a name="AsyncFilter" id="AsyncFilter">AsyncFilter</a> <a name="asyncfilter" id="asyncfilter">Directive</a></h2>
617 <table class="directive">
618 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Set the minimum filter type eligible for asynchronous handling</td></tr>
619 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AsyncFilter request|connection|network</code></td></tr>
620 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AsyncFilter request</code></td></tr>
621 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
622 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
623 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
624 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Only available from Apache 2.5.0 and later.</td></tr>
626 <p>This directive controls the minimum filter levels that are eligible
627 for asynchronous handling. This may be necessary to support legacy external
628 filters that did not handle meta buckets correctly.</p>
630 <p>If set to "network", asynchronous handling will be limited to the network
631 filter only. If set to "connection", all connection and network filters
632 will be eligible for asynchronous handling, including <code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code>.
633 If set to "request", all filters will be eligible for asynchronous handling.</p>
636 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
637 <div class="directive-section"><h2><a name="CGIMapExtension" id="CGIMapExtension">CGIMapExtension</a> <a name="cgimapextension" id="cgimapextension">Directive</a></h2>
638 <table class="directive">
639 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
641 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CGIMapExtension <var>cgi-path</var> <var>.extension</var></code></td></tr>
642 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
643 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
644 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
645 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
646 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>NetWare only</td></tr>
648 <p>This directive is used to control how Apache httpd finds the
649 interpreter used to run CGI scripts. For example, setting
650 <code>CGIMapExtension sys:\foo.nlm .foo</code> will
651 cause all CGI script files with a <code>.foo</code> extension to
652 be passed to the FOO interpreter.</p>
655 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
656 <div class="directive-section"><h2><a name="CGIPassAuth" id="CGIPassAuth">CGIPassAuth</a> <a name="cgipassauth" id="cgipassauth">Directive</a></h2>
657 <table class="directive">
658 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables passing HTTP authorization headers to scripts as CGI
660 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CGIPassAuth On|Off</code></td></tr>
661 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>CGIPassAuth Off</code></td></tr>
662 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
663 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig</td></tr>
664 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
665 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
666 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.4.13 and later</td></tr>
668 <p><code class="directive">CGIPassAuth</code> allows scripts access to HTTP
669 authorization headers such as <code>Authorization</code>, which is
670 required for scripts that implement HTTP Basic authentication.
671 Normally these HTTP headers are hidden from scripts. This is to disallow
672 scripts from seeing user ids and passwords used to access the server when
673 HTTP Basic authentication is enabled in the web server. This directive
674 should be used when scripts are allowed to implement HTTP Basic
677 <p>This directive can be used instead of the compile-time setting
678 <code>SECURITY_HOLE_PASS_AUTHORIZATION</code> which has been available
679 in previous versions of Apache HTTP Server.</p>
681 <p>The setting is respected by any modules which use
682 <code>ap_add_common_vars()</code>, such as <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>,
683 <code class="module"><a href="../mod/mod_cgid.html">mod_cgid</a></code>, <code class="module"><a href="../mod/mod_proxy_fcgi.html">mod_proxy_fcgi</a></code>,
684 <code class="module"><a href="../mod/mod_proxy_scgi.html">mod_proxy_scgi</a></code>, and so on. Notably, it affects
685 modules which don't handle the request in the usual sense but
686 still use this API; examples of this are <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
687 and <code class="module"><a href="../mod/mod_ext_filter.html">mod_ext_filter</a></code>. Third-party modules that don't
688 use <code>ap_add_common_vars()</code> may choose to respect the setting
692 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
693 <div class="directive-section"><h2><a name="ContentDigest" id="ContentDigest">ContentDigest</a> <a name="contentdigest" id="contentdigest">Directive</a></h2>
694 <table class="directive">
695 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables the generation of <code>Content-MD5</code> HTTP Response
697 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ContentDigest On|Off</code></td></tr>
698 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ContentDigest Off</code></td></tr>
699 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
700 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
701 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
702 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
704 <p>This directive enables the generation of
705 <code>Content-MD5</code> headers as defined in RFC1864
706 respectively RFC2616.</p>
708 <p>MD5 is an algorithm for computing a "message digest"
709 (sometimes called "fingerprint") of arbitrary-length data, with
710 a high degree of confidence that any alterations in the data
711 will be reflected in alterations in the message digest.</p>
713 <p>The <code>Content-MD5</code> header provides an end-to-end
714 message integrity check (MIC) of the entity-body. A proxy or
715 client may check this header for detecting accidental
716 modification of the entity-body in transit. Example header:</p>
718 <div class="example"><p><code>
719 Content-MD5: AuLb7Dp1rqtRtxz2m9kRpA==
722 <p>Note that this can cause performance problems on your server
723 since the message digest is computed on every request (the
724 values are not cached).</p>
726 <p><code>Content-MD5</code> is only sent for documents served
727 by the <code class="module"><a href="../mod/core.html">core</a></code>, and not by any module. For example,
728 SSI documents, output from CGI scripts, and byte range responses
729 do not have this header.</p>
732 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
733 <div class="directive-section"><h2><a name="DefaultRuntimeDir" id="DefaultRuntimeDir">DefaultRuntimeDir</a> <a name="defaultruntimedir" id="defaultruntimedir">Directive</a></h2>
734 <table class="directive">
735 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server run-time files</td></tr>
736 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultRuntimeDir <var>directory-path</var></code></td></tr>
737 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultRuntimeDir DEFAULT_REL_RUNTIMEDIR (logs/)</code></td></tr>
738 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
739 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
740 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
741 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.4.2 and later</td></tr>
743 <p>The <code class="directive">DefaultRuntimeDir</code> directive sets the
744 directory in which the server will create various run-time files
745 (shared memory, locks, etc.). If set as a relative path, the full path
746 will be relative to <code class="directive">ServerRoot</code>.</p>
748 <p><strong>Example</strong></p>
749 <pre class="prettyprint lang-config">DefaultRuntimeDir scratch/</pre>
752 <p>The default location of <code class="directive">DefaultRuntimeDir</code> may be
753 modified by changing the <code>DEFAULT_REL_RUNTIMEDIR</code> #define
756 <p>Note: <code class="directive">ServerRoot</code> should be specified before this
757 directive is used. Otherwise, the default value of <code class="directive">ServerRoot</code>
758 would be used to set the base directory.</p>
763 <li><a href="../misc/security_tips.html#serverroot">the
764 security tips</a> for information on how to properly set
765 permissions on the <code class="directive">ServerRoot</code></li>
768 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
769 <div class="directive-section"><h2><a name="DefaultType" id="DefaultType">DefaultType</a> <a name="defaulttype" id="defaulttype">Directive</a></h2>
770 <table class="directive">
771 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>This directive has no effect other than to emit warnings
772 if the value is not <code>none</code>. In prior versions, DefaultType
773 would specify a default media type to assign to response content for
774 which no other media type configuration could be found.
776 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultType <var>media-type|none</var></code></td></tr>
777 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultType none</code></td></tr>
778 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
779 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
780 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
781 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
782 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>All choices except <code>none</code> are DISABLED for 2.3.x and later.
785 <p>This directive has been disabled. For backwards compatibility
786 of configuration files, it may be specified with the value
787 <code>none</code>, meaning no default media type. For example:</p>
789 <pre class="prettyprint lang-config">DefaultType None</pre>
792 <p><code>DefaultType None</code> is only available in
793 httpd-2.2.7 and later.</p>
795 <p>Use the mime.types configuration file and the
796 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code> to configure media
797 type assignments via file extensions, or the
798 <code class="directive"><a href="#forcetype">ForceType</a></code> directive to configure
799 the media type for specific resources. Otherwise, the server will
800 send the response without a Content-Type header field and the
801 recipient may attempt to guess the media type.</p>
804 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
805 <div class="directive-section"><h2><a name="Define" id="Define">Define</a> <a name="define" id="define">Directive</a></h2>
806 <table class="directive">
807 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Define a variable</td></tr>
808 <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>
809 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
810 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
811 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
813 <p>In its one parameter form, <code class="directive">Define</code> is equivalent
814 to passing the <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>. It
815 can be used to toggle the use of
816 <code class="directive"><a href="#ifdefine"><IfDefine></a></code> sections
817 without needing to alter <code>-D</code> arguments in any startup
820 <p>In addition to that, if the second parameter is given, a config variable
821 is set to this value. The variable can be used in the configuration using
822 the <code>${VAR}</code> syntax. The variable is always globally defined
823 and not limited to the scope of the surrounding config section.</p>
825 <pre class="prettyprint lang-config"><IfDefine TEST>
826 Define servername test.example.com
828 <IfDefine !TEST>
829 Define servername www.example.com
833 DocumentRoot "/var/www/${servername}/htdocs"</pre>
836 <p>Variable names may not contain colon ":" characters, to avoid clashes
837 with <code class="directive"><a href="../mod/mod_rewrite.html#rewritemap">RewriteMap</a></code>'s syntax.</p>
839 <p>While this directive is supported in virtual host context,
840 the changes it makes are visible to any later configuration
841 directives, beyond any enclosing virtual host</p>
844 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
845 <div class="directive-section"><h2><a name="Directory" id="Directory"><Directory></a> <a name="directory" id="directory">Directive</a></h2>
846 <table class="directive">
847 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose a group of directives that apply only to the
848 named file-system directory, sub-directories, and their contents.</td></tr>
849 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Directory <var>directory-path</var>>
850 ... </Directory></code></td></tr>
851 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
852 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
853 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
855 <p><code class="directive"><Directory></code> and
856 <code></Directory></code> are used to enclose a group of
857 directives that will apply only to the named directory,
858 sub-directories of that directory, and the files within the respective
859 directories. Any directive that is allowed
860 in a directory context may be used. <var>Directory-path</var> is
861 either the full path to a directory, or a wild-card string using
862 Unix shell-style matching. In a wild-card string, <code>?</code> matches
863 any single character, and <code>*</code> matches any sequences of
864 characters. You may also use <code>[]</code> character ranges. None
865 of the wildcards match a `/' character, so <code><Directory
866 "/*/public_html"></code> will not match
867 <code>/home/user/public_html</code>, but <code><Directory
868 "/home/*/public_html"></code> will match. Example:</p>
870 <pre class="prettyprint lang-config"><Directory "/usr/local/httpd/htdocs">
871 Options Indexes FollowSymLinks
872 </Directory></pre>
875 <p>Directory paths <em>may</em> be quoted, if you like, however, it
876 <em>must</em> be quoted if the path contains spaces. This is because a
877 space would otherwise indicate the end of an argument.</p>
880 <p>Be careful with the <var>directory-path</var> arguments:
881 They have to literally match the filesystem path which Apache httpd uses
882 to access the files. Directives applied to a particular
883 <code><Directory></code> will not apply to files accessed from
884 that same directory via a different path, such as via different symbolic
888 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular
889 expressions</a> can also be used, with the addition of the
890 <code>~</code> character. For example:</p>
892 <pre class="prettyprint lang-config"><Directory ~ "^/www/[0-9]{3}">
894 </Directory></pre>
897 <p>would match directories in <code>/www/</code> that consisted of
900 <p>If multiple (non-regular expression) <code class="directive"><Directory></code> sections
901 match the directory (or one of its parents) containing a document,
902 then the directives are applied in the order of shortest match
903 first, interspersed with the directives from the <a href="#accessfilename">.htaccess</a> files. For example,
906 <pre class="prettyprint lang-config"><Directory "/">
910 <Directory "/home">
911 AllowOverride FileInfo
912 </Directory></pre>
915 <p>for access to the document <code>/home/web/dir/doc.html</code>
919 <li>Apply directive <code>AllowOverride None</code>
920 (disabling <code>.htaccess</code> files).</li>
922 <li>Apply directive <code>AllowOverride FileInfo</code> (for
923 directory <code>/home</code>).</li>
925 <li>Apply any <code>FileInfo</code> directives in
926 <code>/home/.htaccess</code>, <code>/home/web/.htaccess</code> and
927 <code>/home/web/dir/.htaccess</code> in that order.</li>
930 <p>Regular expressions are not considered until after all of the
931 normal sections have been applied. Then all of the regular
932 expressions are tested in the order they appeared in the
933 configuration file. For example, with</p>
935 <pre class="prettyprint lang-config"><Directory ~ "abc$">
936 # ... directives here ...
937 </Directory></pre>
940 <p>the regular expression section won't be considered until after
941 all normal <code class="directive"><Directory></code>s and
942 <code>.htaccess</code> files have been applied. Then the regular
943 expression will match on <code>/home/abc/public_html/abc</code> and
944 the corresponding <code class="directive"><Directory></code> will
947 <p><strong>Note that the default access for
948 <code><Directory "/"></code> is to permit all access.
949 This means that Apache httpd will serve any file mapped from an URL. It is
950 recommended that you change this with a block such
953 <pre class="prettyprint lang-config"><Directory "/">
955 </Directory></pre>
958 <p><strong>and then override this for directories you
959 <em>want</em> accessible. See the <a href="../misc/security_tips.html">Security Tips</a> page for more
960 details.</strong></p>
962 <p>The directory sections occur in the <code>httpd.conf</code> file.
963 <code class="directive"><Directory></code> directives
964 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>
968 <li><a href="../sections.html">How <Directory>,
969 <Location> and <Files> sections work</a> for an
970 explanation of how these different sections are combined when a
971 request is received</li>
974 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
975 <div class="directive-section"><h2><a name="DirectoryMatch" id="DirectoryMatch"><DirectoryMatch></a> <a name="directorymatch" id="directorymatch">Directive</a></h2>
976 <table class="directive">
977 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose directives that apply to
978 the contents of file-system directories matching a regular expression.</td></tr>
979 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><DirectoryMatch <var>regex</var>>
980 ... </DirectoryMatch></code></td></tr>
981 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
982 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
983 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
985 <p><code class="directive"><DirectoryMatch></code> and
986 <code></DirectoryMatch></code> are used to enclose a group
987 of directives which will apply only to the named directory (and the files within),
988 the same as <code class="directive"><a href="#directory"><Directory></a></code>.
989 However, it takes as an argument a
990 <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>. For example:</p>
992 <pre class="prettyprint lang-config"><DirectoryMatch "^/www/(.+/)?[0-9]{3}/">
994 </DirectoryMatch></pre>
997 <p>matches directories in <code>/www/</code> (or any subdirectory thereof)
998 that consist of three numbers.</p>
1000 <div class="note"><h3>Compatability</h3>
1001 Prior to 2.3.9, this directive implicitly applied to sub-directories
1002 (like <code class="directive"><a href="#directory"><Directory></a></code>) and
1003 could not match the end of line symbol ($). In 2.3.9 and later,
1004 only directories that match the expression are affected by the enclosed
1008 <div class="note"><h3>Trailing Slash</h3>
1009 This directive applies to requests for directories that may or may
1010 not end in a trailing slash, so expressions that are anchored to the
1011 end of line ($) must be written with care.
1014 <p>From 2.4.8 onwards, named groups and backreferences are captured and
1015 written to the environment with the corresponding name prefixed with
1016 "MATCH_" and in upper case. This allows elements of paths to be referenced
1017 from within <a href="../expr.html">expressions</a> and modules like
1018 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
1019 (unnamed) backreferences are ignored. Use named groups instead.</p>
1021 <pre class="prettyprint lang-config"><DirectoryMatch "^/var/www/combined/(?<sitename>[^/]+)">
1022 Require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
1023 </DirectoryMatch></pre>
1028 <li><code class="directive"><a href="#directory"><Directory></a></code> for
1029 a description of how regular expressions are mixed in with normal
1030 <code class="directive"><Directory></code>s</li>
1031 <li><a href="../sections.html">How <Directory>, <Location> and
1032 <Files> sections work</a> for an explanation of how these different
1033 sections are combined when a request is received</li>
1036 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1037 <div class="directive-section"><h2><a name="DocumentRoot" id="DocumentRoot">DocumentRoot</a> <a name="documentroot" id="documentroot">Directive</a></h2>
1038 <table class="directive">
1039 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory that forms the main document tree visible
1040 from the web</td></tr>
1041 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DocumentRoot <var>directory-path</var></code></td></tr>
1042 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DocumentRoot /usr/local/apache/htdocs</code></td></tr>
1043 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1044 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1045 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1047 <p>This directive sets the directory from which <code class="program"><a href="../programs/httpd.html">httpd</a></code>
1048 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
1049 path from the requested URL to the document root to make the
1050 path to the document. Example:</p>
1052 <pre class="prettyprint lang-config">DocumentRoot "/usr/web"</pre>
1055 <p>then an access to
1056 <code>http://my.example.com/index.html</code> refers to
1057 <code>/usr/web/index.html</code>. If the <var>directory-path</var> is
1058 not absolute then it is assumed to be relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1060 <p>The <code class="directive">DocumentRoot</code> should be specified without
1061 a trailing slash.</p>
1065 <li><a href="../urlmapping.html#documentroot">Mapping URLs to Filesystem
1069 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1070 <div class="directive-section"><h2><a name="Else" id="Else"><Else></a> <a name="else" id="else">Directive</a></h2>
1071 <table class="directive">
1072 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if the condition of a
1073 previous <code class="directive"><a href="#if"><If></a></code> or
1074 <code class="directive"><a href="#elseif"><ElseIf></a></code> section is not
1075 satisfied by a request at runtime</td></tr>
1076 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Else> ... </Else></code></td></tr>
1077 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1078 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1079 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1080 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1082 <p>The <code class="directive"><Else></code> applies the enclosed
1083 directives if and only if the most recent
1084 <code class="directive"><If></code> or
1085 <code class="directive"><ElseIf></code> section
1086 in the same scope has not been applied.
1087 For example: In </p>
1089 <pre class="prettyprint lang-config"><If "-z req('Host')">
1097 <p> The <code class="directive"><If></code> would match HTTP/1.0
1098 requests without a <var>Host:</var> header and the
1099 <code class="directive"><Else></code> would match requests
1100 with a <var>Host:</var> header.</p>
1105 <li><code class="directive"><a href="#if"><If></a></code></li>
1106 <li><code class="directive"><a href="#elseif"><ElseIf></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="ElseIf" id="ElseIf"><ElseIf></a> <a name="elseif" id="elseif">Directive</a></h2>
1117 <table class="directive">
1118 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is satisfied
1119 by a request at runtime while the condition of a previous
1120 <code class="directive"><a href="#if"><If></a></code> or
1121 <code class="directive"><ElseIf></code> section is not
1123 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><ElseIf <var>expression</var>> ... </ElseIf></code></td></tr>
1124 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1125 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1126 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1127 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1129 <p>The <code class="directive"><ElseIf></code> applies the enclosed
1130 directives if and only if both the given condition evaluates to true and
1131 the most recent <code class="directive"><If></code> or
1132 <code class="directive"><ElseIf></code> section in the same scope has
1133 not been applied. For example: In </p>
1135 <pre class="prettyprint lang-config"><If "-R '10.1.0.0/16'">
1138 <ElseIf "-R '10.0.0.0/8'">
1146 <p>The <code class="directive"><ElseIf></code> would match if
1147 the remote address of a request belongs to the subnet 10.0.0.0/8 but
1148 not to the subnet 10.1.0.0/16.</p>
1153 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
1154 for a complete reference and more examples.</li>
1155 <li><code class="directive"><a href="#if"><If></a></code></li>
1156 <li><code class="directive"><a href="#else"><Else></a></code></li>
1157 <li><a href="../sections.html">How <Directory>, <Location>,
1158 <Files> sections work</a> for an explanation of how these
1159 different sections are combined when a request is received.
1160 <code class="directive"><If></code>,
1161 <code class="directive"><ElseIf></code>, and
1162 <code class="directive"><Else></code> are applied last.</li>
1165 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1166 <div class="directive-section"><h2><a name="EnableMMAP" id="EnableMMAP">EnableMMAP</a> <a name="enablemmap" id="enablemmap">Directive</a></h2>
1167 <table class="directive">
1168 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use memory-mapping to read files during delivery</td></tr>
1169 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableMMAP On|Off</code></td></tr>
1170 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableMMAP On</code></td></tr>
1171 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1172 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1173 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1174 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1176 <p>This directive controls whether the <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use
1177 memory-mapping if it needs to read the contents of a file during
1178 delivery. By default, when the handling of a request requires
1179 access to the data within a file -- for example, when delivering a
1180 server-parsed file using <code class="module"><a href="../mod/mod_include.html">mod_include</a></code> -- Apache httpd
1181 memory-maps the file if the OS supports it.</p>
1183 <p>This memory-mapping sometimes yields a performance improvement.
1184 But in some environments, it is better to disable the memory-mapping
1185 to prevent operational problems:</p>
1188 <li>On some multiprocessor systems, memory-mapping can reduce the
1189 performance of the <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</li>
1190 <li>Deleting or truncating a file while <code class="program"><a href="../programs/httpd.html">httpd</a></code>
1191 has it memory-mapped can cause <code class="program"><a href="../programs/httpd.html">httpd</a></code> to
1192 crash with a segmentation fault.
1196 <p>For server configurations that are vulnerable to these problems,
1197 you should disable memory-mapping of delivered files by specifying:</p>
1199 <pre class="prettyprint lang-config">EnableMMAP Off</pre>
1202 <p>For NFS mounted files, this feature may be disabled explicitly for
1203 the offending files by specifying:</p>
1205 <pre class="prettyprint lang-config"><Directory "/path-to-nfs-files">
1207 </Directory></pre>
1211 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1212 <div class="directive-section"><h2><a name="EnableSendfile" id="EnableSendfile">EnableSendfile</a> <a name="enablesendfile" id="enablesendfile">Directive</a></h2>
1213 <table class="directive">
1214 <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>
1215 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableSendfile On|Off</code></td></tr>
1216 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableSendfile Off</code></td></tr>
1217 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1218 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1219 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1220 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1221 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Default changed to Off in
1222 version 2.3.9.</td></tr>
1224 <p>This directive controls whether <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use the
1225 sendfile support from the kernel to transmit file contents to the client.
1226 By default, when the handling of a request requires no access
1227 to the data within a file -- for example, when delivering a
1228 static file -- Apache httpd uses sendfile to deliver the file contents
1229 without ever reading the file if the OS supports it.</p>
1231 <p>This sendfile mechanism avoids separate read and send operations,
1232 and buffer allocations. But on some platforms or within some
1233 filesystems, it is better to disable this feature to avoid
1234 operational problems:</p>
1237 <li>Some platforms may have broken sendfile support that the build
1238 system did not detect, especially if the binaries were built on
1239 another box and moved to such a machine with broken sendfile
1241 <li>On Linux the use of sendfile triggers TCP-checksum
1242 offloading bugs on certain networking cards when using IPv6.</li>
1243 <li>On Linux on Itanium, <code>sendfile</code> may be unable to handle
1244 files over 2GB in size.</li>
1245 <li>With a network-mounted <code class="directive"><a href="#documentroot">DocumentRoot</a></code> (e.g., NFS, SMB, CIFS, FUSE),
1246 the kernel may be unable to serve the network file through
1250 <p>For server configurations that are not vulnerable to these problems,
1251 you may enable this feature by specifying:</p>
1253 <pre class="prettyprint lang-config">EnableSendfile On</pre>
1256 <p>For network mounted files, this feature may be disabled explicitly
1257 for the offending files by specifying:</p>
1259 <pre class="prettyprint lang-config"><Directory "/path-to-nfs-files">
1261 </Directory></pre>
1263 <p>Please note that the per-directory and .htaccess configuration
1264 of <code class="directive">EnableSendfile</code> is not supported by
1265 <code class="module"><a href="../mod/mod_cache_disk.html">mod_cache_disk</a></code>.
1266 Only global definition of <code class="directive">EnableSendfile</code>
1267 is taken into account by the module.
1271 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1272 <div class="directive-section"><h2><a name="Error" id="Error">Error</a> <a name="error" id="error">Directive</a></h2>
1273 <table class="directive">
1274 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Abort configuration parsing with a custom error message</td></tr>
1275 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Error <var>message</var></code></td></tr>
1276 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1277 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1278 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1279 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.3.9 and later</td></tr>
1281 <p>If an error can be detected within the configuration, this
1282 directive can be used to generate a custom error message, and halt
1283 configuration parsing. The typical use is for reporting required
1284 modules which are missing from the configuration.</p>
1286 <pre class="prettyprint lang-config"># Example
1287 # ensure that mod_include is loaded
1288 <IfModule !include_module>
1289 Error "mod_include is required by mod_foo. Load it with LoadModule."
1292 # ensure that exactly one of SSL,NOSSL is defined
1293 <IfDefine SSL>
1294 <IfDefine NOSSL>
1295 Error "Both SSL and NOSSL are defined. Define only one of them."
1298 <IfDefine !SSL>
1299 <IfDefine !NOSSL>
1300 Error "Either SSL or NOSSL must be defined."
1302 </IfDefine></pre>
1307 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1308 <div class="directive-section"><h2><a name="ErrorDocument" id="ErrorDocument">ErrorDocument</a> <a name="errordocument" id="errordocument">Directive</a></h2>
1309 <table class="directive">
1310 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>What the server will return to the client
1311 in case of an error</td></tr>
1312 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ErrorDocument <var>error-code</var> <var>document</var></code></td></tr>
1313 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1314 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1315 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1316 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1318 <p>In the event of a problem or error, Apache httpd can be configured
1319 to do one of four things,</p>
1322 <li>output a simple hardcoded error message</li>
1324 <li>output a customized message</li>
1326 <li>internally redirect to a local <var>URL-path</var> to handle the
1329 <li>redirect to an external <var>URL</var> to handle the
1333 <p>The first option is the default, while options 2-4 are
1334 configured using the <code class="directive">ErrorDocument</code>
1335 directive, which is followed by the HTTP response code and a URL
1336 or a message. Apache httpd will sometimes offer additional information
1337 regarding the problem/error.</p>
1339 <p>From 2.4.13, <a href="../expr.html">expression syntax</a> can be
1340 used inside the directive to produce dynamic strings and URLs.</p>
1342 <p>URLs can begin with a slash (/) for local web-paths (relative
1343 to the <code class="directive"><a href="#documentroot">DocumentRoot</a></code>), or be a
1344 full URL which the client can resolve. Alternatively, a message
1345 can be provided to be displayed by the browser. Note that deciding
1346 whether the parameter is an URL, a path or a message is performed
1347 before any expression is parsed. Examples:</p>
1349 <pre class="prettyprint lang-config">ErrorDocument 500 http://foo.example.com/cgi-bin/tester
1350 ErrorDocument 404 /cgi-bin/bad_urls.pl
1351 ErrorDocument 401 /subscription_info.html
1352 ErrorDocument 403 "Sorry can't allow you access today"
1353 ErrorDocument 403 Forbidden!
1354 ErrorDocument 403 /cgi-bin/forbidden.pl?referrer=%{escape:%{HTTP_REFERER}}</pre>
1357 <p>Additionally, the special value <code>default</code> can be used
1358 to specify Apache httpd's simple hardcoded message. While not required
1359 under normal circumstances, <code>default</code> will restore
1360 Apache httpd's simple hardcoded message for configurations that would
1361 otherwise inherit an existing <code class="directive">ErrorDocument</code>.</p>
1363 <pre class="prettyprint lang-config">ErrorDocument 404 /cgi-bin/bad_urls.pl
1365 <Directory "/web/docs">
1366 ErrorDocument 404 default
1367 </Directory></pre>
1370 <p>Note that when you specify an <code class="directive">ErrorDocument</code>
1371 that points to a remote URL (ie. anything with a method such as
1372 <code>http</code> in front of it), Apache HTTP Server will send a redirect to the
1373 client to tell it where to find the document, even if the
1374 document ends up being on the same server. This has several
1375 implications, the most important being that the client will not
1376 receive the original error status code, but instead will
1377 receive a redirect status code. This in turn can confuse web
1378 robots and other clients which try to determine if a URL is
1379 valid using the status code. In addition, if you use a remote
1380 URL in an <code>ErrorDocument 401</code>, the client will not
1381 know to prompt the user for a password since it will not
1382 receive the 401 status code. Therefore, <strong>if you use an
1383 <code>ErrorDocument 401</code> directive, then it must refer to a local
1384 document.</strong></p>
1386 <p>Microsoft Internet Explorer (MSIE) will by default ignore
1387 server-generated error messages when they are "too small" and substitute
1388 its own "friendly" error messages. The size threshold varies depending on
1389 the type of error, but in general, if you make your error document
1390 greater than 512 bytes, then MSIE will show the server-generated
1391 error rather than masking it. More information is available in
1392 Microsoft Knowledge Base article <a href="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q294807">Q294807</a>.</p>
1394 <p>Although most error messages can be overridden, there are certain
1395 circumstances where the internal messages are used regardless of the
1396 setting of <code class="directive"><a href="#errordocument">ErrorDocument</a></code>. In
1397 particular, if a malformed request is detected, normal request processing
1398 will be immediately halted and the internal error message returned.
1399 This is necessary to guard against security problems caused by
1402 <p>If you are using mod_proxy, you may wish to enable
1403 <code class="directive"><a href="../mod/mod_proxy.html#proxyerroroverride">ProxyErrorOverride</a></code> so that you can provide
1404 custom error messages on behalf of your Origin servers. If you don't enable ProxyErrorOverride,
1405 Apache httpd will not generate custom error documents for proxied content.</p>
1409 <li><a href="../custom-error.html">documentation of
1410 customizable responses</a></li>
1413 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1414 <div class="directive-section"><h2><a name="ErrorLog" id="ErrorLog">ErrorLog</a> <a name="errorlog" id="errorlog">Directive</a></h2>
1415 <table class="directive">
1416 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Location where the server will log errors</td></tr>
1417 <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>
1418 <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>
1419 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1420 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1421 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1423 <p>The <code class="directive">ErrorLog</code> directive sets the name of
1424 the file to which the server will log any errors it encounters. If
1425 the <var>file-path</var> is not absolute then it is assumed to be
1426 relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1428 <pre class="prettyprint lang-config">ErrorLog "/var/log/httpd/error_log"</pre>
1431 <p>If the <var>file-path</var>
1432 begins with a pipe character "<code>|</code>" then it is assumed to be a
1433 command to spawn to handle the error log.</p>
1435 <pre class="prettyprint lang-config">ErrorLog "|/usr/local/bin/httpd_errors"</pre>
1438 <p>See the notes on <a href="../logs.html#piped">piped logs</a> for
1439 more information.</p>
1441 <p>Using <code>syslog</code> instead of a filename enables logging
1442 via syslogd(8) if the system supports it and if <code class="module"><a href="../mod/mod_syslog.html">mod_syslog</a></code>
1443 is loaded. The default is to use syslog facility <code>local7</code>,
1444 but you can override this by using the <code>syslog:<var>facility</var></code>
1445 syntax where <var>facility</var> can be one of the names usually documented in
1446 syslog(1). The facility is effectively global, and if it is changed
1447 in individual virtual hosts, the final facility specified affects the
1450 <pre class="prettyprint lang-config">ErrorLog syslog:user</pre>
1453 <p>Additional modules can provide their own ErrorLog providers. The syntax
1454 is similar to the <code>syslog</code> example above.</p>
1456 <p>SECURITY: See the <a href="../misc/security_tips.html#serverroot">security tips</a>
1457 document for details on why your security could be compromised
1458 if the directory where log files are stored is writable by
1459 anyone other than the user that starts the server.</p>
1460 <div class="warning"><h3>Note</h3>
1461 <p>When entering a file path on non-Unix platforms, care should be taken
1462 to make sure that only forward slashes are used even though the platform
1463 may allow the use of back slashes. In general it is a good idea to always
1464 use forward slashes throughout the configuration files.</p>
1469 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1470 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1473 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1474 <div class="directive-section"><h2><a name="ErrorLogFormat" id="ErrorLogFormat">ErrorLogFormat</a> <a name="errorlogformat" id="errorlogformat">Directive</a></h2>
1475 <table class="directive">
1476 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Format specification for error log entries</td></tr>
1477 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code> ErrorLogFormat [connection|request] <var>format</var></code></td></tr>
1478 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1479 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1480 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1482 <p><code class="directive">ErrorLogFormat</code> allows to specify what
1483 supplementary information is logged in the error log in addition to the
1484 actual log message.</p>
1486 <pre class="prettyprint lang-config">#Simple example
1487 ErrorLogFormat "[%t] [%l] [pid %P] %F: %E: [client %a] %M"</pre>
1490 <p>Specifying <code>connection</code> or <code>request</code> as first
1491 parameter allows to specify additional formats, causing additional
1492 information to be logged when the first message is logged for a specific
1493 connection or request, respectively. This additional information is only
1494 logged once per connection/request. If a connection or request is processed
1495 without causing any log message, the additional information is not logged
1498 <p>It can happen that some format string items do not produce output. For
1499 example, the Referer header is only present if the log message is
1500 associated to a request and the log message happens at a time when the
1501 Referer header has already been read from the client. If no output is
1502 produced, the default behavior is to delete everything from the preceding
1503 space character to the next space character. This means the log line is
1504 implicitly divided into fields on non-whitespace to whitespace transitions.
1505 If a format string item does not produce output, the whole field is
1506 omitted. For example, if the remote address <code>%a</code> in the log
1507 format <code>[%t] [%l] [%a] %M </code> is not available, the surrounding
1508 brackets are not logged either. Space characters can be escaped with a
1509 backslash to prevent them from delimiting a field. The combination '% '
1510 (percent space) is a zero-width field delimiter that does not produce any
1513 <p>The above behavior can be changed by adding modifiers to the format
1514 string item. A <code>-</code> (minus) modifier causes a minus to be logged if the
1515 respective item does not produce any output. In once-per-connection/request
1516 formats, it is also possible to use the <code>+</code> (plus) modifier. If an
1517 item with the plus modifier does not produce any output, the whole line is
1520 <p>A number as modifier can be used to assign a log severity level to a
1521 format item. The item will only be logged if the severity of the log
1522 message is not higher than the specified log severity level. The number can
1523 range from 1 (alert) over 4 (warn) and 7 (debug) to 15 (trace8).</p>
1525 <p>For example, here's what would happen if you added modifiers to
1526 the <code>%{Referer}i</code> token, which logs the
1527 <code>Referer</code> request header.</p>
1529 <table class="bordered"><tr class="header"><th>Modified Token</th><th>Meaning</th></tr>
1531 <td><code>%-{Referer}i</code></td>
1532 <td>Logs a <code>-</code> if <code>Referer</code> is not set.</td>
1535 <td><code>%+{Referer}i</code></td>
1536 <td>Omits the entire line if <code>Referer</code> is not set.</td>
1539 <td><code>%4{Referer}i</code></td>
1540 <td>Logs the <code>Referer</code> only if the log message severity
1541 is higher than 4.</td>
1545 <p>Some format string items accept additional parameters in braces.</p>
1547 <table class="bordered"><tr class="header"><th>Format String</th> <th>Description</th></tr>
1548 <tr><td><code>%%</code></td>
1549 <td>The percent sign</td></tr>
1550 <tr class="odd"><td><code>%a</code></td>
1551 <td>Client IP address and port of the request</td></tr>
1552 <tr><td><code>%{c}a</code></td>
1553 <td>Underlying peer IP address and port of the connection (see the
1554 <code class="module"><a href="../mod/mod_remoteip.html">mod_remoteip</a></code> module)</td></tr>
1555 <tr class="odd"><td><code>%A</code></td>
1556 <td>Local IP-address and port</td></tr>
1557 <tr><td><code>%{<em>name</em>}e</code></td>
1558 <td>Request environment variable <em>name</em></td></tr>
1559 <tr class="odd"><td><code>%E</code></td>
1560 <td>APR/OS error status code and string</td></tr>
1561 <tr><td><code>%F</code></td>
1562 <td>Source file name and line number of the log call</td></tr>
1563 <tr class="odd"><td><code>%{<em>name</em>}i</code></td>
1564 <td>Request header <em>name</em></td></tr>
1565 <tr><td><code>%k</code></td>
1566 <td>Number of keep-alive requests on this connection</td></tr>
1567 <tr class="odd"><td><code>%l</code></td>
1568 <td>Loglevel of the message</td></tr>
1569 <tr><td><code>%L</code></td>
1570 <td>Log ID of the request</td></tr>
1571 <tr class="odd"><td><code>%{c}L</code></td>
1572 <td>Log ID of the connection</td></tr>
1573 <tr><td><code>%{C}L</code></td>
1574 <td>Log ID of the connection if used in connection scope, empty otherwise</td></tr>
1575 <tr class="odd"><td><code>%m</code></td>
1576 <td>Name of the module logging the message</td></tr>
1577 <tr><td><code>%M</code></td>
1578 <td>The actual log message</td></tr>
1579 <tr class="odd"><td><code>%{<em>name</em>}n</code></td>
1580 <td>Request note <em>name</em></td></tr>
1581 <tr><td><code>%P</code></td>
1582 <td>Process ID of current process</td></tr>
1583 <tr class="odd"><td><code>%T</code></td>
1584 <td>Thread ID of current thread</td></tr>
1585 <tr><td><code>%{g}T</code></td>
1586 <td>System unique thread ID of current thread (the same ID as
1587 displayed by e.g. <code>top</code>; currently Linux only)</td></tr>
1588 <tr class="odd"><td><code>%t</code></td>
1589 <td>The current time</td></tr>
1590 <tr><td><code>%{u}t</code></td>
1591 <td>The current time including micro-seconds</td></tr>
1592 <tr class="odd"><td><code>%{cu}t</code></td>
1593 <td>The current time in compact ISO 8601 format, including
1594 micro-seconds</td></tr>
1595 <tr><td><code>%v</code></td>
1596 <td>The canonical <code class="directive"><a href="#servername">ServerName</a></code>
1597 of the current server.</td></tr>
1598 <tr class="odd"><td><code>%V</code></td>
1599 <td>The server name of the server serving the request according to the
1600 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code>
1602 <tr><td><code>\ </code> (backslash space)</td>
1603 <td>Non-field delimiting space</td></tr>
1604 <tr class="odd"><td><code>% </code> (percent space)</td>
1605 <td>Field delimiter (no output)</td></tr>
1608 <p>The log ID format <code>%L</code> produces a unique id for a connection
1609 or request. This can be used to correlate which log lines belong to the
1610 same connection or request, which request happens on which connection.
1611 A <code>%L</code> format string is also available in
1612 <code class="module"><a href="../mod/mod_log_config.html">mod_log_config</a></code> to allow to correlate access log entries
1613 with error log lines. If <code class="module"><a href="../mod/mod_unique_id.html">mod_unique_id</a></code> is loaded, its
1614 unique id will be used as log ID for requests.</p>
1616 <pre class="prettyprint lang-config">#Example (default format for threaded MPMs)
1617 ErrorLogFormat "[%{u}t] [%-m:%l] [pid %P:tid %T] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"</pre>
1620 <p>This would result in error messages such as:</p>
1622 <div class="example"><p><code>
1623 [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
1626 <p>Notice that, as discussed above, some fields are omitted
1627 entirely because they are not defined.</p>
1629 <pre class="prettyprint lang-config">#Example (similar to the 2.2.x format)
1630 ErrorLogFormat "[%t] [%l] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"</pre>
1633 <pre class="prettyprint lang-config">#Advanced example with request/connection log IDs
1634 ErrorLogFormat "[%{uc}t] [%-m:%-l] [R:%L] [C:%{C}L] %7F: %E: %M"
1635 ErrorLogFormat request "[%{uc}t] [R:%L] Request %k on C:%{c}L pid:%P tid:%T"
1636 ErrorLogFormat request "[%{uc}t] [R:%L] UA:'%+{User-Agent}i'"
1637 ErrorLogFormat request "[%{uc}t] [R:%L] Referer:'%+{Referer}i'"
1638 ErrorLogFormat connection "[%{uc}t] [C:%{c}L] local\ %a remote\ %A"</pre>
1644 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
1645 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1646 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1649 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1650 <div class="directive-section"><h2><a name="ExtendedStatus" id="ExtendedStatus">ExtendedStatus</a> <a name="extendedstatus" id="extendedstatus">Directive</a></h2>
1651 <table class="directive">
1652 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Keep track of extended status information for each
1654 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ExtendedStatus On|Off</code></td></tr>
1655 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ExtendedStatus Off[*]</code></td></tr>
1656 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
1657 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1658 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1660 <p>This option tracks additional data per worker about the
1661 currently executing request and creates a utilization summary.
1662 You can see these variables during runtime by configuring
1663 <code class="module"><a href="../mod/mod_status.html">mod_status</a></code>. Note that other modules may
1664 rely on this scoreboard.</p>
1666 <p>This setting applies to the entire server and cannot be
1667 enabled or disabled on a virtualhost-by-virtualhost basis.
1668 The collection of extended status information can slow down
1669 the server. Also note that this setting cannot be changed
1670 during a graceful restart.</p>
1673 <p>Note that loading <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> will change
1674 the default behavior to ExtendedStatus On, while other
1675 third party modules may do the same. Such modules rely on
1676 collecting detailed information about the state of all workers.
1677 The default is changed by <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> beginning
1678 with version 2.3.6. The previous default was always Off.</p>
1683 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1684 <div class="directive-section"><h2><a name="FileETag" id="FileETag">FileETag</a> <a name="fileetag" id="fileetag">Directive</a></h2>
1685 <table class="directive">
1686 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>File attributes used to create the ETag
1687 HTTP response header for static files</td></tr>
1688 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>FileETag <var>component</var> ...</code></td></tr>
1689 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>FileETag MTime Size</code></td></tr>
1690 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1691 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1692 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1693 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1694 <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
1698 The <code class="directive">FileETag</code> directive configures the file
1699 attributes that are used to create the <code>ETag</code> (entity
1700 tag) response header field when the document is based on a static file.
1701 (The <code>ETag</code> value is used in cache management to save
1702 network bandwidth.) The
1703 <code class="directive">FileETag</code> directive allows you to choose
1704 which of these -- if any -- should be used. The recognized keywords are:
1708 <dt><strong>INode</strong></dt>
1709 <dd>The file's i-node number will be included in the calculation</dd>
1710 <dt><strong>MTime</strong></dt>
1711 <dd>The date and time the file was last modified will be included</dd>
1712 <dt><strong>Size</strong></dt>
1713 <dd>The number of bytes in the file will be included</dd>
1714 <dt><strong>All</strong></dt>
1715 <dd>All available fields will be used. This is equivalent to:
1716 <pre class="prettyprint lang-config">FileETag INode MTime Size</pre>
1718 <dt><strong>None</strong></dt>
1719 <dd>If a document is file-based, no <code>ETag</code> field will be
1720 included in the response</dd>
1723 <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
1724 keywords may be prefixed with either <code>+</code> or <code>-</code>,
1725 which allow changes to be made to the default setting inherited
1726 from a broader scope. Any keyword appearing without such a prefix
1727 immediately and completely cancels the inherited setting.</p>
1729 <p>If a directory's configuration includes
1730 <code>FileETag INode MTime Size</code>, and a
1731 subdirectory's includes <code>FileETag -INode</code>,
1732 the setting for that subdirectory (which will be inherited by
1733 any sub-subdirectories that don't override it) will be equivalent to
1734 <code>FileETag MTime Size</code>.</p>
1735 <div class="warning"><h3>Warning</h3>
1736 Do not change the default for directories or locations that have WebDAV
1737 enabled and use <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> as a storage provider.
1738 <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> uses <code>MTime Size</code>
1739 as a fixed format for <code>ETag</code> comparisons on conditional requests.
1740 These conditional requests will break if the <code>ETag</code> format is
1741 changed via <code class="directive">FileETag</code>.
1743 <div class="note"><h3>Server Side Includes</h3>
1744 An ETag is not generated for responses parsed by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
1745 since the response entity can change without a change of the INode, MTime, or Size
1746 of the static file with embedded SSI directives.
1751 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1752 <div class="directive-section"><h2><a name="Files" id="Files"><Files></a> <a name="files" id="files">Directive</a></h2>
1753 <table class="directive">
1754 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to matched
1756 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Files <var>filename</var>> ... </Files></code></td></tr>
1757 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1758 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1759 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1760 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1762 <p>The <code class="directive"><Files></code> directive
1763 limits the scope of the enclosed directives by filename. It is comparable
1764 to the <code class="directive"><a href="#directory"><Directory></a></code>
1765 and <code class="directive"><a href="#location"><Location></a></code>
1766 directives. It should be matched with a <code></Files></code>
1767 directive. The directives given within this section will be applied to
1768 any object with a basename (last component of filename) matching the
1769 specified filename. <code class="directive"><Files></code>
1770 sections are processed in the order they appear in the
1771 configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
1772 <code>.htaccess</code> files are read, but before <code class="directive"><a href="#location"><Location></a></code> sections. Note
1773 that <code class="directive"><Files></code> can be nested
1774 inside <code class="directive"><a href="#directory"><Directory></a></code> sections to restrict the
1775 portion of the filesystem they apply to.</p>
1777 <p>The <var>filename</var> argument should include a filename, or
1778 a wild-card string, where <code>?</code> matches any single character,
1779 and <code>*</code> matches any sequences of characters.</p>
1780 <pre class="prettyprint lang-config"><Files "cat.html">
1781 # Insert stuff that applies to cat.html here
1784 <Files "?at.*">
1785 # This would apply to cat.html, bat.html, hat.php and so on.
1786 </Files></pre>
1788 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
1789 can also be used, with the addition of the
1790 <code>~</code> character. For example:</p>
1792 <pre class="prettyprint lang-config"><Files ~ "\.(gif|jpe?g|png)$">
1794 </Files></pre>
1797 <p>would match most common Internet graphics formats. <code class="directive"><a href="#filesmatch"><FilesMatch></a></code> is preferred,
1800 <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
1801 <code>.htaccess</code> files. This allows users to control access to
1802 their own files, at a file-by-file level.</p>
1807 <li><a href="../sections.html">How <Directory>, <Location>
1808 and <Files> sections work</a> for an explanation of how these
1809 different sections are combined when a request is received</li>
1812 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1813 <div class="directive-section"><h2><a name="FilesMatch" id="FilesMatch"><FilesMatch></a> <a name="filesmatch" id="filesmatch">Directive</a></h2>
1814 <table class="directive">
1815 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to regular-expression matched
1817 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><FilesMatch <var>regex</var>> ... </FilesMatch></code></td></tr>
1818 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1819 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1820 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1821 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1823 <p>The <code class="directive"><FilesMatch></code> directive
1824 limits the scope of the enclosed directives by filename, just as the
1825 <code class="directive"><a href="#files"><Files></a></code> directive
1826 does. However, it accepts a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular
1827 expression</a>. For example:</p>
1829 <pre class="prettyprint lang-config"><FilesMatch ".+\.(gif|jpe?g|png)$">
1831 </FilesMatch></pre>
1834 <p>would match most common Internet graphics formats.</p>
1836 <div class="note">The <code>.+</code> at the start of the regex ensures that
1837 files named <code>.png</code>, or <code>.gif</code>, for example,
1838 are not matched.</div>
1840 <p>From 2.4.8 onwards, named groups and backreferences are captured and
1841 written to the environment with the corresponding name prefixed with
1842 "MATCH_" and in upper case. This allows elements of files to be referenced
1843 from within <a href="../expr.html">expressions</a> and modules like
1844 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
1845 (unnamed) backreferences are ignored. Use named groups instead.</p>
1847 <pre class="prettyprint lang-config"><FilesMatch "^(?<sitename>[^/]+)">
1848 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
1849 </FilesMatch></pre>
1854 <li><a href="../sections.html">How <Directory>, <Location>
1855 and <Files> sections work</a> for an explanation of how these
1856 different sections are combined when a request is received</li>
1859 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1860 <div class="directive-section"><h2><a name="ForceType" id="ForceType">ForceType</a> <a name="forcetype" id="forcetype">Directive</a></h2>
1861 <table class="directive">
1862 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be served with the specified
1863 media type in the HTTP Content-Type header field</td></tr>
1864 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ForceType <var>media-type</var>|None</code></td></tr>
1865 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
1866 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1867 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1868 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1870 <p>When placed into an <code>.htaccess</code> file or a
1871 <code class="directive"><a href="#directory"><Directory></a></code>, or
1872 <code class="directive"><a href="#location"><Location></a></code> or
1873 <code class="directive"><a href="#files"><Files></a></code>
1874 section, this directive forces all matching files to be served
1875 with the content type identification given by
1876 <var>media-type</var>. For example, if you had a directory full of
1877 GIF files, but did not want to label them all with <code>.gif</code>,
1878 you might want to use:</p>
1880 <pre class="prettyprint lang-config">ForceType image/gif</pre>
1883 <p>Note that this directive overrides other indirect media type
1884 associations defined in mime.types or via the
1885 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code>.</p>
1887 <p>You can also override more general
1888 <code class="directive">ForceType</code> settings
1889 by using the value of <code>None</code>:</p>
1891 <pre class="prettyprint lang-config"># force all files to be image/gif:
1892 <Location "/images">
1896 # but normal mime-type associations here:
1897 <Location "/images/mixed">
1899 </Location></pre>
1902 <p>This directive primarily overrides the content types generated for
1903 static files served out of the filesystem. For resources other than
1904 static files, where the generator of the response typically specifies
1905 a Content-Type, this directive has no effect.</p>
1908 <div class="note"><h3>Note</h3>
1909 <p>If no handler is explicitly set for a request, the specified content
1910 type will also be used as the handler name. </p>
1912 <p>When explicit directives such as
1913 <code class="directive"><a href="#sethandler">SetHandler</a></code> or
1914 <code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code> do not apply
1915 to the current request, the internal handler name normally set by those
1916 directives is instead set to the content type specified by this directive.
1919 This is a historical behavior that some third-party modules
1920 (such as mod_php) may look for a "synthetic" content type used only to
1921 signal the module to take responsibility for the matching request.
1924 <p>Configurations that rely on such "synthetic" types should be avoided.
1925 Additionally, configurations that restrict access to
1926 <code class="directive"><a href="#sethandler">SetHandler</a></code> or
1927 <code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code> should
1928 restrict access to this directive as well.</p>
1933 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1934 <div class="directive-section"><h2><a name="GprofDir" id="GprofDir">GprofDir</a> <a name="gprofdir" id="gprofdir">Directive</a></h2>
1935 <table class="directive">
1936 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory to write gmon.out profiling data to. </td></tr>
1937 <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>
1938 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1939 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1940 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1942 <p>When the server has been compiled with gprof profiling support,
1943 <code class="directive">GprofDir</code> causes <code>gmon.out</code> files to
1944 be written to the specified directory when the process exits. If the
1945 argument ends with a percent symbol ('%'), subdirectories are created
1946 for each process id.</p>
1948 <p>This directive currently only works with the <code class="module"><a href="../mod/prefork.html">prefork</a></code>
1952 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1953 <div class="directive-section"><h2><a name="HostnameLookups" id="HostnameLookups">HostnameLookups</a> <a name="hostnamelookups" id="hostnamelookups">Directive</a></h2>
1954 <table class="directive">
1955 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables DNS lookups on client IP addresses</td></tr>
1956 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>HostnameLookups On|Off|Double</code></td></tr>
1957 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>HostnameLookups Off</code></td></tr>
1958 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1959 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1960 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1962 <p>This directive enables DNS lookups so that host names can be
1963 logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
1964 The value <code>Double</code> refers to doing double-reverse
1965 DNS lookup. That is, after a reverse lookup is performed, a forward
1966 lookup is then performed on that result. At least one of the IP
1967 addresses in the forward lookup must match the original
1968 address. (In "tcpwrappers" terminology this is called
1969 <code>PARANOID</code>.)</p>
1971 <p>Regardless of the setting, when <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code> is
1972 used for controlling access by hostname, a double reverse lookup
1973 will be performed. This is necessary for security. Note that the
1974 result of this double-reverse isn't generally available unless you
1975 set <code>HostnameLookups Double</code>. For example, if only
1976 <code>HostnameLookups On</code> and a request is made to an object
1977 that is protected by hostname restrictions, regardless of whether
1978 the double-reverse fails or not, CGIs will still be passed the
1979 single-reverse result in <code>REMOTE_HOST</code>.</p>
1981 <p>The default is <code>Off</code> in order to save the network
1982 traffic for those sites that don't truly need the reverse
1983 lookups done. It is also better for the end users because they
1984 don't have to suffer the extra latency that a lookup entails.
1985 Heavily loaded sites should leave this directive
1986 <code>Off</code>, since DNS lookups can take considerable
1987 amounts of time. The utility <code class="program"><a href="../programs/logresolve.html">logresolve</a></code>, compiled by
1988 default to the <code>bin</code> subdirectory of your installation
1989 directory, can be used to look up host names from logged IP addresses
1992 <p>Finally, if you have <a href="mod_authz_host.html#reqhost">hostname-based Require
1993 directives</a>, a hostname lookup will be performed regardless of
1994 the setting of <code>HostnameLookups</code>.</p>
1997 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1998 <div class="directive-section"><h2><a name="If" id="If"><If></a> <a name="if" id="if">Directive</a></h2>
1999 <table class="directive">
2000 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is
2001 satisfied by a request at runtime</td></tr>
2002 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><If <var>expression</var>> ... </If></code></td></tr>
2003 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2004 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2005 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2006 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2008 <p>The <code class="directive"><If></code> directive
2009 evaluates an expression at runtime, and applies the enclosed
2010 directives if and only if the expression evaluates to true.
2013 <pre class="prettyprint lang-config"><If "-z req('Host')"></pre>
2016 <p>would match HTTP/1.0 requests without a <var>Host:</var> header.
2017 Expressions may contain various shell-like operators for string
2018 comparison (<code>==</code>, <code>!=</code>, <code><</code>, ...),
2019 integer comparison (<code>-eq</code>, <code>-ne</code>, ...),
2020 and others (<code>-n</code>, <code>-z</code>, <code>-f</code>, ...).
2021 It is also possible to use regular expressions, </p>
2023 <pre class="prettyprint lang-config"><If "%{QUERY_STRING} =~ /(delete|commit)=.*?elem/"></pre>
2026 <p>shell-like pattern matches and many other operations. These operations
2027 can be done on request headers (<code>req</code>), environment variables
2028 (<code>env</code>), and a large number of other properties. The full
2029 documentation is available in <a href="../expr.html">Expressions in
2030 Apache HTTP Server</a>.</p>
2032 <p>Only directives that support the <a href="directive-dict.html#Context">directory context</a> can be used within this configuration section.</p>
2034 <div class="warning">
2035 Certain variables, such as <code>CONTENT_TYPE</code> and other
2036 response headers, are set after <If> conditions have already
2037 been evaluated, and so will not be available to use in this
2044 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
2045 for a complete reference and more examples.</li>
2046 <li><code class="directive"><a href="#elseif"><ElseIf></a></code></li>
2047 <li><code class="directive"><a href="#else"><Else></a></code></li>
2048 <li><a href="../sections.html">How <Directory>, <Location>,
2049 <Files> sections work</a> for an explanation of how these
2050 different sections are combined when a request is received.
2051 <code class="directive"><If></code>,
2052 <code class="directive"><ElseIf></code>, and
2053 <code class="directive"><Else></code> are applied last.</li>
2056 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2057 <div class="directive-section"><h2><a name="IfDefine" id="IfDefine"><IfDefine></a> <a name="ifdefine" id="ifdefine">Directive</a></h2>
2058 <table class="directive">
2059 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that will be processed only
2060 if a test is true at startup</td></tr>
2061 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfDefine [!]<var>parameter-name</var>> ...
2062 </IfDefine></code></td></tr>
2063 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2064 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2065 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2066 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2068 <p>The <code><IfDefine <var>test</var>>...</IfDefine>
2069 </code> section is used to mark directives that are conditional. The
2070 directives within an <code class="directive"><IfDefine></code>
2071 section are only processed if the <var>test</var> is true. If <var>
2072 test</var> is false, everything between the start and end markers is
2075 <p>The <var>test</var> in the <code class="directive"><IfDefine></code> section directive can be one of two forms:</p>
2078 <li><var>parameter-name</var></li>
2080 <li><code>!</code><var>parameter-name</var></li>
2083 <p>In the former case, the directives between the start and end
2084 markers are only processed if the parameter named
2085 <var>parameter-name</var> is defined. The second format reverses
2086 the test, and only processes the directives if
2087 <var>parameter-name</var> is <strong>not</strong> defined.</p>
2089 <p>The <var>parameter-name</var> argument is a define as given on the
2090 <code class="program"><a href="../programs/httpd.html">httpd</a></code> command line via <code>-D<var>parameter</var>
2091 </code> at the time the server was started or by the <code class="directive"><a href="#define">Define</a></code> directive.</p>
2093 <p><code class="directive"><IfDefine></code> sections are
2094 nest-able, which can be used to implement simple
2095 multiple-parameter tests. Example:</p>
2097 <div class="example"><p><code>httpd -DReverseProxy -DUseCache -DMemCache ...</code></p></div>
2098 <pre class="prettyprint lang-config"><IfDefine ReverseProxy>
2099 LoadModule proxy_module modules/mod_proxy.so
2100 LoadModule proxy_http_module modules/mod_proxy_http.so
2101 <IfDefine UseCache>
2102 LoadModule cache_module modules/mod_cache.so
2103 <IfDefine MemCache>
2104 LoadModule mem_cache_module modules/mod_mem_cache.so
2106 <IfDefine !MemCache>
2107 LoadModule cache_disk_module modules/mod_cache_disk.so
2110 </IfDefine></pre>
2114 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2115 <div class="directive-section"><h2><a name="IfModule" id="IfModule"><IfModule></a> <a name="ifmodule" id="ifmodule">Directive</a></h2>
2116 <table class="directive">
2117 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that are processed conditional on the
2118 presence or absence of a specific module</td></tr>
2119 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfModule [!]<var>module-file</var>|<var>module-identifier</var>> ...
2120 </IfModule></code></td></tr>
2121 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2122 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2123 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2124 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2126 <p>The <code><IfModule <var>test</var>>...</IfModule></code>
2127 section is used to mark directives that are conditional on the presence of
2128 a specific module. The directives within an <code class="directive"><IfModule></code> section are only processed if the <var>test</var>
2129 is true. If <var>test</var> is false, everything between the start and
2130 end markers is ignored.</p>
2132 <p>The <var>test</var> in the <code class="directive"><IfModule></code> section directive can be one of two forms:</p>
2135 <li><var>module</var></li>
2137 <li>!<var>module</var></li>
2140 <p>In the former case, the directives between the start and end
2141 markers are only processed if the module named <var>module</var>
2142 is included in Apache httpd -- either compiled in or
2143 dynamically loaded using <code class="directive"><a href="../mod/mod_so.html#loadmodule">LoadModule</a></code>. The second format reverses the test,
2144 and only processes the directives if <var>module</var> is
2145 <strong>not</strong> included.</p>
2147 <p>The <var>module</var> argument can be either the module identifier or
2148 the file name of the module, at the time it was compiled. For example,
2149 <code>rewrite_module</code> is the identifier and
2150 <code>mod_rewrite.c</code> is the file name. If a module consists of
2151 several source files, use the name of the file containing the string
2152 <code>STANDARD20_MODULE_STUFF</code>.</p>
2154 <p><code class="directive"><IfModule></code> sections are
2155 nest-able, which can be used to implement simple multiple-module
2158 <div class="note">This section should only be used if you need to have one
2159 configuration file that works whether or not a specific module
2160 is available. In normal operation, directives need not be
2161 placed in <code class="directive"><IfModule></code>
2165 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2166 <div class="directive-section"><h2><a name="Include" id="Include">Include</a> <a name="include" id="include">Directive</a></h2>
2167 <table class="directive">
2168 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2169 the server configuration files</td></tr>
2170 <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>
2171 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2172 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2173 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2174 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Directory
2175 wildcard matching available in 2.3.6 and later</td></tr>
2177 <p>This directive allows inclusion of other configuration files
2178 from within the server configuration files.</p>
2180 <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used
2181 in the filename or directory parts of the path to include several files
2182 at once, in alphabetical order. In addition, if
2183 <code class="directive">Include</code> points to a directory, rather than a file,
2184 Apache httpd will read all files in that directory and any subdirectory.
2185 However, including entire directories is not recommended, because it is
2186 easy to accidentally leave temporary files in a directory that can cause
2187 <code class="program"><a href="../programs/httpd.html">httpd</a></code> to fail. Instead, we encourage you to use the
2188 wildcard syntax shown below, to include files that match a particular
2189 pattern, such as *.conf, for example.</p>
2191 <p>The <code class="directive"><a href="#include">Include</a></code> directive will
2192 <strong>fail with an error</strong> if a wildcard expression does not
2193 match any file. The <code class="directive"><a href="#includeoptional">IncludeOptional</a></code>
2194 directive can be used if non-matching wildcards should be ignored.</p>
2196 <p>The file path specified may be an absolute path, or may be relative
2197 to the <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory.</p>
2201 <pre class="prettyprint lang-config">Include /usr/local/apache2/conf/ssl.conf
2202 Include /usr/local/apache2/conf/vhosts/*.conf</pre>
2205 <p>Or, providing paths relative to your <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory:</p>
2207 <pre class="prettyprint lang-config">Include conf/ssl.conf
2208 Include conf/vhosts/*.conf</pre>
2211 <p>Wildcards may be included in the directory or file portion of the
2212 path. This example will fail if there is no subdirectory in conf/vhosts
2213 that contains at least one *.conf file:</p>
2215 <pre class="prettyprint lang-config">Include conf/vhosts/*/*.conf</pre>
2218 <p>Alternatively, the following command will just be ignored in case of
2219 missing files or directories:</p>
2221 <pre class="prettyprint lang-config">IncludeOptional conf/vhosts/*/*.conf</pre>
2227 <li><code class="directive"><a href="#includeoptional">IncludeOptional</a></code></li>
2228 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2231 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2232 <div class="directive-section"><h2><a name="IncludeOptional" id="IncludeOptional">IncludeOptional</a> <a name="includeoptional" id="includeoptional">Directive</a></h2>
2233 <table class="directive">
2234 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2235 the server configuration files</td></tr>
2236 <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>
2237 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2238 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2239 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2240 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in 2.3.6 and later</td></tr>
2242 <p>This directive allows inclusion of other configuration files
2243 from within the server configuration files. It works identically to the
2244 <code class="directive"><a href="#include">Include</a></code> directive, with the
2245 exception that if wildcards do not match any file or directory, the
2246 <code class="directive"><a href="#includeoptional">IncludeOptional</a></code> directive will be
2247 silently ignored instead of causing an error.</p>
2251 <li><code class="directive"><a href="#include">Include</a></code></li>
2252 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2255 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2256 <div class="directive-section"><h2><a name="KeepAlive" id="KeepAlive">KeepAlive</a> <a name="keepalive" id="keepalive">Directive</a></h2>
2257 <table class="directive">
2258 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables HTTP persistent connections</td></tr>
2259 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAlive On|Off</code></td></tr>
2260 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAlive On</code></td></tr>
2261 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2262 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2263 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2265 <p>The Keep-Alive extension to HTTP/1.0 and the persistent
2266 connection feature of HTTP/1.1 provide long-lived HTTP sessions
2267 which allow multiple requests to be sent over the same TCP
2268 connection. In some cases this has been shown to result in an
2269 almost 50% speedup in latency times for HTML documents with
2270 many images. To enable Keep-Alive connections, set
2271 <code>KeepAlive On</code>.</p>
2273 <p>For HTTP/1.0 clients, Keep-Alive connections will only be
2274 used if they are specifically requested by a client. In
2275 addition, a Keep-Alive connection with an HTTP/1.0 client can
2276 only be used when the length of the content is known in
2277 advance. This implies that dynamic content such as CGI output,
2278 SSI pages, and server-generated directory listings will
2279 generally not use Keep-Alive connections to HTTP/1.0 clients.
2280 For HTTP/1.1 clients, persistent connections are the default
2281 unless otherwise specified. If the client requests it, chunked
2282 encoding will be used in order to send content of unknown
2283 length over persistent connections.</p>
2285 <p>When a client uses a Keep-Alive connection, it will be counted
2286 as a single "request" for the <code class="directive"><a href="../mod/mpm_common.html#maxconnectionsperchild">MaxConnectionsPerChild</a></code> directive, regardless
2287 of how many requests are sent using the connection.</p>
2291 <li><code class="directive"><a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></code></li>
2294 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2295 <div class="directive-section"><h2><a name="KeepAliveTimeout" id="KeepAliveTimeout">KeepAliveTimeout</a> <a name="keepalivetimeout" id="keepalivetimeout">Directive</a></h2>
2296 <table class="directive">
2297 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for subsequent
2298 requests on a persistent connection</td></tr>
2299 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAliveTimeout <var>num</var>[ms]</code></td></tr>
2300 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAliveTimeout 5</code></td></tr>
2301 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2302 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2303 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2305 <p>The number of seconds Apache httpd will wait for a subsequent
2306 request before closing the connection. By adding a postfix of ms the
2307 timeout can be also set in milliseconds. Once a request has been
2308 received, the timeout value specified by the
2309 <code class="directive"><a href="#timeout">Timeout</a></code> directive applies.</p>
2311 <p>Setting <code class="directive">KeepAliveTimeout</code> to a high value
2312 may cause performance problems in heavily loaded servers. The
2313 higher the timeout, the more server processes will be kept
2314 occupied waiting on connections with idle clients.</p>
2316 <p>If <code class="directive">KeepAliveTimeout</code> is <strong>not</strong>
2317 set for a name-based virtual host, the value of the first defined
2318 virtual host best matching the local IP and port will be used.</p>
2321 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2322 <div class="directive-section"><h2><a name="Limit" id="Limit"><Limit></a> <a name="limit" id="limit">Directive</a></h2>
2323 <table class="directive">
2324 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict enclosed access controls to only certain HTTP
2326 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Limit <var>method</var> [<var>method</var>] ... > ...
2327 </Limit></code></td></tr>
2328 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2329 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2330 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2331 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2333 <p>Access controls are normally effective for
2334 <strong>all</strong> access methods, and this is the usual
2335 desired behavior. <strong>In the general case, access control
2336 directives should not be placed within a
2337 <code class="directive"><Limit></code> section.</strong></p>
2339 <p>The purpose of the <code class="directive"><Limit></code>
2340 directive is to restrict the effect of the access controls to the
2341 nominated HTTP methods. For all other methods, the access
2342 restrictions that are enclosed in the <code class="directive"><Limit></code> bracket <strong>will have no
2343 effect</strong>. The following example applies the access control
2344 only to the methods <code>POST</code>, <code>PUT</code>, and
2345 <code>DELETE</code>, leaving all other methods unprotected:</p>
2347 <pre class="prettyprint lang-config"><Limit POST PUT DELETE>
2349 </Limit></pre>
2352 <p>The method names listed can be one or more of: <code>GET</code>,
2353 <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
2354 <code>CONNECT</code>, <code>OPTIONS</code>,
2355 <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
2356 <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
2357 <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
2358 case-sensitive.</strong> If <code>GET</code> is used, it will also
2359 restrict <code>HEAD</code> requests. The <code>TRACE</code> method
2360 cannot be limited (see <code class="directive"><a href="#traceenable">TraceEnable</a></code>).</p>
2362 <div class="warning">A <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section should always be
2363 used in preference to a <code class="directive"><Limit></code>
2364 section when restricting access, since a <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section provides protection
2365 against arbitrary methods.</div>
2367 <p>The <code class="directive"><Limit></code> and
2368 <code class="directive"><a href="#limitexcept"><LimitExcept></a></code>
2369 directives may be nested. In this case, each successive level of
2370 <code class="directive"><Limit></code> or <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> directives must
2371 further restrict the set of methods to which access controls apply.</p>
2373 <div class="warning">When using
2374 <code class="directive"><Limit></code> or
2375 <code class="directive"><LimitExcept></code> directives with
2376 the <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directive,
2377 note that the first <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code>
2378 to succeed authorizes the request, regardless of the presence of other
2379 <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directives.</div>
2381 <p>For example, given the following configuration, all users will
2382 be authorized for <code>POST</code> requests, and the
2383 <code>Require group editors</code> directive will be ignored
2386 <pre class="prettyprint lang-config"><LimitExcept GET>
2388 </LimitExcept>
2390 Require group editors
2391 </Limit></pre>
2395 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2396 <div class="directive-section"><h2><a name="LimitExcept" id="LimitExcept"><LimitExcept></a> <a name="limitexcept" id="limitexcept">Directive</a></h2>
2397 <table class="directive">
2398 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict access controls to all HTTP methods
2399 except the named ones</td></tr>
2400 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LimitExcept <var>method</var> [<var>method</var>] ... > ...
2401 </LimitExcept></code></td></tr>
2402 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2403 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2404 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2405 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2407 <p><code class="directive"><LimitExcept></code> and
2408 <code></LimitExcept></code> are used to enclose
2409 a group of access control directives which will then apply to any
2410 HTTP access method <strong>not</strong> listed in the arguments;
2411 i.e., it is the opposite of a <code class="directive"><a href="#limit"><Limit></a></code> section and can be used to control
2412 both standard and nonstandard/unrecognized methods. See the
2413 documentation for <code class="directive"><a href="#limit"><Limit></a></code> for more details.</p>
2417 <pre class="prettyprint lang-config"><LimitExcept POST GET>
2419 </LimitExcept></pre>
2424 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2425 <div class="directive-section"><h2><a name="LimitInternalRecursion" id="LimitInternalRecursion">LimitInternalRecursion</a> <a name="limitinternalrecursion" id="limitinternalrecursion">Directive</a></h2>
2426 <table class="directive">
2427 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine maximum number of internal redirects and nested
2428 subrequests</td></tr>
2429 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitInternalRecursion <var>number</var> [<var>number</var>]</code></td></tr>
2430 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitInternalRecursion 10</code></td></tr>
2431 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2432 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2433 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2435 <p>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
2436 redirects the original request to a CGI script. A subrequest is Apache httpd's
2437 mechanism to find out what would happen for some URI if it were requested.
2438 For example, <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> uses subrequests to look for the
2439 files listed in the <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
2442 <p><code class="directive">LimitInternalRecursion</code> prevents the server
2443 from crashing when entering an infinite loop of internal redirects or
2444 subrequests. Such loops are usually caused by misconfigurations.</p>
2446 <p>The directive stores two different limits, which are evaluated on
2447 per-request basis. The first <var>number</var> is the maximum number of
2448 internal redirects that may follow each other. The second <var>number</var>
2449 determines how deeply subrequests may be nested. If you specify only one
2450 <var>number</var>, it will be assigned to both limits.</p>
2452 <pre class="prettyprint lang-config">LimitInternalRecursion 5</pre>
2456 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2457 <div class="directive-section"><h2><a name="LimitRequestBody" id="LimitRequestBody">LimitRequestBody</a> <a name="limitrequestbody" id="limitrequestbody">Directive</a></h2>
2458 <table class="directive">
2459 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restricts the total size of the HTTP request body sent
2460 from the client</td></tr>
2461 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestBody <var>bytes</var></code></td></tr>
2462 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestBody 0</code></td></tr>
2463 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2464 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2465 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2466 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2468 <p>This directive specifies the number of <var>bytes</var> from 0
2469 (meaning unlimited) to 2147483647 (2GB) that are allowed in a
2470 request body. See the note below for the limited applicability
2471 to proxy requests.</p>
2473 <p>The <code class="directive">LimitRequestBody</code> directive allows
2474 the user to set a limit on the allowed size of an HTTP request
2475 message body within the context in which the directive is given
2476 (server, per-directory, per-file or per-location). If the client
2477 request exceeds that limit, the server will return an error
2478 response instead of servicing the request. The size of a normal
2479 request message body will vary greatly depending on the nature of
2480 the resource and the methods allowed on that resource. CGI scripts
2481 typically use the message body for retrieving form information.
2482 Implementations of the <code>PUT</code> method will require
2483 a value at least as large as any representation that the server
2484 wishes to accept for that resource.</p>
2486 <p>This directive gives the server administrator greater
2487 control over abnormal client request behavior, which may be
2488 useful for avoiding some forms of denial-of-service
2491 <p>If, for example, you are permitting file upload to a particular
2492 location and wish to limit the size of the uploaded file to 100K,
2493 you might use the following directive:</p>
2495 <pre class="prettyprint lang-config">LimitRequestBody 102400</pre>
2498 <div class="note"><p>For a full description of how this directive is interpreted by
2499 proxy requests, see the <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> documentation.</p>
2504 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2505 <div class="directive-section"><h2><a name="LimitRequestFields" id="LimitRequestFields">LimitRequestFields</a> <a name="limitrequestfields" id="limitrequestfields">Directive</a></h2>
2506 <table class="directive">
2507 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of HTTP request header fields that
2508 will be accepted from the client</td></tr>
2509 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFields <var>number</var></code></td></tr>
2510 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFields 100</code></td></tr>
2511 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2512 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2513 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2515 <p><var>Number</var> is an integer from 0 (meaning unlimited) to
2516 32767. The default value is defined by the compile-time
2517 constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
2520 <p>The <code class="directive">LimitRequestFields</code> directive allows
2521 the server administrator to modify the limit on the number of
2522 request header fields allowed in an HTTP request. A server needs
2523 this value to be larger than the number of fields that a normal
2524 client request might include. The number of request header fields
2525 used by a client rarely exceeds 20, but this may vary among
2526 different client implementations, often depending upon the extent
2527 to which a user has configured their browser to support detailed
2528 content negotiation. Optional HTTP extensions are often expressed
2529 using request header fields.</p>
2531 <p>This directive gives the server administrator greater
2532 control over abnormal client request behavior, which may be
2533 useful for avoiding some forms of denial-of-service attacks.
2534 The value should be increased if normal clients see an error
2535 response from the server that indicates too many fields were
2536 sent in the request.</p>
2540 <pre class="prettyprint lang-config">LimitRequestFields 50</pre>
2543 <div class="warning"><h3>Warning</h3>
2544 <p> When name-based virtual hosting is used, the value for this
2545 directive is taken from the default (first-listed) virtual host for the
2546 local IP and port combination.</p>
2551 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2552 <div class="directive-section"><h2><a name="LimitRequestFieldSize" id="LimitRequestFieldSize">LimitRequestFieldSize</a> <a name="limitrequestfieldsize" id="limitrequestfieldsize">Directive</a></h2>
2553 <table class="directive">
2554 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of the HTTP request header allowed from the
2556 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFieldSize <var>bytes</var></code></td></tr>
2557 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFieldSize 8190</code></td></tr>
2558 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2559 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2560 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2562 <p>This directive specifies the number of <var>bytes</var>
2563 that will be allowed in an HTTP request header.</p>
2565 <p>The <code class="directive">LimitRequestFieldSize</code> directive
2566 allows the server administrator to set the limit
2567 on the allowed size of an HTTP request header field. A server
2568 needs this value to be large enough to hold any one header field
2569 from a normal client request. The size of a normal request header
2570 field will vary greatly among different client implementations,
2571 often depending upon the extent to which a user has configured
2572 their browser to support detailed content negotiation. SPNEGO
2573 authentication headers can be up to 12392 bytes.</p>
2575 <p>This directive gives the server administrator greater
2576 control over abnormal client request behavior, which may be
2577 useful for avoiding some forms of denial-of-service attacks.</p>
2581 <pre class="prettyprint lang-config">LimitRequestFieldSize 4094</pre>
2584 <div class="note">Under normal conditions, the value should not be changed from
2587 <div class="warning"><h3>Warning</h3>
2588 <p> When name-based virtual hosting is used, the value for this
2589 directive is taken from the default (first-listed) virtual host best
2590 matching the current IP address and port combination.</p>
2594 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2595 <div class="directive-section"><h2><a name="LimitRequestLine" id="LimitRequestLine">LimitRequestLine</a> <a name="limitrequestline" id="limitrequestline">Directive</a></h2>
2596 <table class="directive">
2597 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limit the size of the HTTP request line that will be accepted
2598 from the client</td></tr>
2599 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestLine <var>bytes</var></code></td></tr>
2600 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestLine 8190</code></td></tr>
2601 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2602 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2603 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2605 <p>This directive sets the number of <var>bytes</var> that will be
2606 allowed on the HTTP request-line.</p>
2608 <p>The <code class="directive">LimitRequestLine</code> directive allows
2609 the server administrator to set the limit on the allowed size
2610 of a client's HTTP request-line. Since the request-line consists of the
2611 HTTP method, URI, and protocol version, the
2612 <code class="directive">LimitRequestLine</code> directive places a
2613 restriction on the length of a request-URI allowed for a request
2614 on the server. A server needs this value to be large enough to
2615 hold any of its resource names, including any information that
2616 might be passed in the query part of a <code>GET</code> request.</p>
2618 <p>This directive gives the server administrator greater
2619 control over abnormal client request behavior, which may be
2620 useful for avoiding some forms of denial-of-service attacks.</p>
2624 <pre class="prettyprint lang-config">LimitRequestLine 4094</pre>
2627 <div class="note">Under normal conditions, the value should not be changed from
2630 <div class="warning"><h3>Warning</h3>
2631 <p> When name-based virtual hosting is used, the value for this
2632 directive is taken from the default (first-listed) virtual host best
2633 matching the current IP address and port combination.</p>
2638 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2639 <div class="directive-section"><h2><a name="LimitXMLRequestBody" id="LimitXMLRequestBody">LimitXMLRequestBody</a> <a name="limitxmlrequestbody" id="limitxmlrequestbody">Directive</a></h2>
2640 <table class="directive">
2641 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of an XML-based request body</td></tr>
2642 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitXMLRequestBody <var>bytes</var></code></td></tr>
2643 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitXMLRequestBody 1000000</code></td></tr>
2644 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2645 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2646 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2647 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2649 <p>Limit (in bytes) on maximum size of an XML-based request
2650 body. A value of <code>0</code> will disable any checking.</p>
2654 <pre class="prettyprint lang-config">LimitXMLRequestBody 0</pre>
2659 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2660 <div class="directive-section"><h2><a name="Location" id="Location"><Location></a> <a name="location" id="location">Directive</a></h2>
2661 <table class="directive">
2662 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to matching
2664 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Location
2665 <var>URL-path</var>|<var>URL</var>> ... </Location></code></td></tr>
2666 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2667 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2668 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2670 <p>The <code class="directive"><Location></code> directive
2671 limits the scope of the enclosed directives by URL. It is similar to the
2672 <code class="directive"><a href="#directory"><Directory></a></code>
2673 directive, and starts a subsection which is terminated with a
2674 <code></Location></code> directive. <code class="directive"><Location></code> sections are processed in the
2675 order they appear in the configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
2676 <code>.htaccess</code> files are read, and after the <code class="directive"><a href="#files"><Files></a></code> sections.</p>
2678 <p><code class="directive"><Location></code> sections operate
2679 completely outside the filesystem. This has several consequences.
2680 Most importantly, <code class="directive"><Location></code>
2681 directives should not be used to control access to filesystem
2682 locations. Since several different URLs may map to the same
2683 filesystem location, such access controls may by circumvented.</p>
2685 <p>The enclosed directives will be applied to the request if the path component
2686 of the URL meets <em>any</em> of the following criteria:
2689 <li>The specified location matches exactly the path component of the URL.
2691 <li>The specified location, which ends in a forward slash, is a prefix
2692 of the path component of the URL (treated as a context root).
2694 <li>The specified location, with the addition of a trailing slash, is a
2695 prefix of the path component of the URL (also treated as a context root).
2699 In the example below, where no trailing slash is used, requests to
2700 /private1, /private1/ and /private1/file.txt will have the enclosed
2701 directives applied, but /private1other would not.
2703 <pre class="prettyprint lang-config"><Location "/private1">
2705 </Location></pre>
2708 In the example below, where a trailing slash is used, requests to
2709 /private2/ and /private2/file.txt will have the enclosed
2710 directives applied, but /private2 and /private2other would not.
2712 <pre class="prettyprint lang-config"><Location "/private2<em>/</em>">
2714 </Location></pre>
2717 <div class="note"><h3>When to use <code class="directive"><Location></code></h3>
2719 <p>Use <code class="directive"><Location></code> to apply
2720 directives to content that lives outside the filesystem. For
2721 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
2722 <code><Location "/"></code>, which is an easy way to
2723 apply a configuration to the entire server.</p>
2726 <p>For all origin (non-proxy) requests, the URL to be matched is a
2727 URL-path of the form <code>/path/</code>. <em>No scheme, hostname,
2728 port, or query string may be included.</em> For proxy requests, the
2729 URL to be matched is of the form
2730 <code>scheme://servername/path</code>, and you must include the
2733 <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
2734 any single character, and <code>*</code> matches any sequences of
2735 characters. Neither wildcard character matches a / in the URL-path.</p>
2737 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
2738 can also be used, with the addition of the <code>~</code>
2739 character. For example:</p>
2741 <pre class="prettyprint lang-config"><Location ~ "/(extra|special)/data">
2743 </Location></pre>
2746 <p>would match URLs that contained the substring <code>/extra/data</code>
2747 or <code>/special/data</code>. The directive <code class="directive"><a href="#locationmatch"><LocationMatch></a></code> behaves
2748 identical to the regex version of <code class="directive"><Location></code>, and is preferred, for the
2749 simple reason that <code>~</code> is hard to distinguish from
2750 <code>-</code> in many fonts.</p>
2752 <p>The <code class="directive"><Location></code>
2753 functionality is especially useful when combined with the
2754 <code class="directive"><a href="#sethandler">SetHandler</a></code>
2755 directive. For example, to enable status requests but allow them
2756 only from browsers at <code>example.com</code>, you might use:</p>
2758 <pre class="prettyprint lang-config"><Location "/status">
2759 SetHandler server-status
2760 Require host example.com
2761 </Location></pre>
2764 <div class="note"><h3>Note about / (slash)</h3>
2765 <p>The slash character has special meaning depending on where in a
2766 URL it appears. People may be used to its behavior in the filesystem
2767 where multiple adjacent slashes are frequently collapsed to a single
2768 slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
2769 <code>/home/foo</code>). In URL-space this is not necessarily true.
2770 The <code class="directive"><a href="#locationmatch"><LocationMatch></a></code>
2771 directive and the regex version of <code class="directive"><Location></code> require you to explicitly specify multiple
2772 slashes if that is your intention.</p>
2774 <p>For example, <code><LocationMatch "^/abc"></code> would match
2775 the request URL <code>/abc</code> but not the request URL <code>
2776 //abc</code>. The (non-regex) <code class="directive"><Location></code> directive behaves similarly when used for
2777 proxy requests. But when (non-regex) <code class="directive"><Location></code> is used for non-proxy requests it will
2778 implicitly match multiple slashes with a single slash. For example,
2779 if you specify <code><Location "/abc/def"></code> and the
2780 request is to <code>/abc//def</code> then it will match.</p>
2785 <li><a href="../sections.html">How <Directory>, <Location>
2786 and <Files> sections work</a> for an explanation of how these
2787 different sections are combined when a request is received.</li>
2788 <li><code class="directive"><a href="#locationmatch">LocationMatch</a></code></li>
2791 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2792 <div class="directive-section"><h2><a name="LocationMatch" id="LocationMatch"><LocationMatch></a> <a name="locationmatch" id="locationmatch">Directive</a></h2>
2793 <table class="directive">
2794 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to regular-expression
2795 matching URLs</td></tr>
2796 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LocationMatch
2797 <var>regex</var>> ... </LocationMatch></code></td></tr>
2798 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2799 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2800 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2802 <p>The <code class="directive"><LocationMatch></code> directive
2803 limits the scope of the enclosed directives by URL, in an identical manner
2804 to <code class="directive"><a href="#location"><Location></a></code>. However,
2805 it takes a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
2806 as an argument instead of a simple string. For example:</p>
2808 <pre class="prettyprint lang-config"><LocationMatch "/(extra|special)/data">
2810 </LocationMatch></pre>
2813 <p>would match URLs that contained the substring <code>/extra/data</code>
2814 or <code>/special/data</code>.</p>
2816 <div class="note"><p>If the intent is that a URL <strong>starts with</strong>
2817 <code>/extra/data</code>, rather than merely
2818 <strong>contains</strong> <code>/extra/data</code>, prefix the
2819 regular expression with a <code>^</code> to require this.</p>
2821 <pre class="prettyprint lang-config"><LocationMatch "^/(extra|special)/data"></pre>
2825 <p>From 2.4.8 onwards, named groups and backreferences are captured and
2826 written to the environment with the corresponding name prefixed with
2827 "MATCH_" and in upper case. This allows elements of URLs to be referenced
2828 from within <a href="../expr.html">expressions</a> and modules like
2829 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
2830 (unnamed) backreferences are ignored. Use named groups instead.</p>
2832 <pre class="prettyprint lang-config"><LocationMatch "^/combined/(?<sitename>[^/]+)">
2833 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
2834 </LocationMatch></pre>
2839 <li><a href="../sections.html">How <Directory>, <Location>
2840 and <Files> sections work</a> for an explanation of how these
2841 different sections are combined when a request is received</li>
2844 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2845 <div class="directive-section"><h2><a name="LogLevel" id="LogLevel">LogLevel</a> <a name="loglevel" id="loglevel">Directive</a></h2>
2846 <table class="directive">
2847 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Controls the verbosity of the ErrorLog</td></tr>
2848 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel [<var>module</var>:]<var>level</var>
2849 [<var>module</var>:<var>level</var>] ...
2851 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LogLevel warn</code></td></tr>
2852 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2853 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2854 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2855 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Per-module and per-directory configuration is available in
2856 Apache HTTP Server 2.3.6 and later</td></tr>
2858 <p><code class="directive">LogLevel</code> adjusts the verbosity of the
2859 messages recorded in the error logs (see <code class="directive"><a href="#errorlog">ErrorLog</a></code> directive). The following
2860 <var>level</var>s are available, in order of decreasing
2863 <table class="bordered">
2866 <th><strong>Level</strong> </th>
2868 <th><strong>Description</strong> </th>
2870 <th><strong>Example</strong> </th>
2874 <td><code>emerg</code> </td>
2876 <td>Emergencies - system is unusable.</td>
2878 <td>"Child cannot open lock file. Exiting"</td>
2882 <td><code>alert</code> </td>
2884 <td>Action must be taken immediately.</td>
2886 <td>"getpwuid: couldn't determine user name from uid"</td>
2890 <td><code>crit</code> </td>
2892 <td>Critical Conditions.</td>
2894 <td>"socket: Failed to get a socket, exiting child"</td>
2898 <td><code>error</code> </td>
2900 <td>Error conditions.</td>
2902 <td>"Premature end of script headers"</td>
2906 <td><code>warn</code> </td>
2908 <td>Warning conditions.</td>
2910 <td>"child process 1234 did not exit, sending another
2915 <td><code>notice</code> </td>
2917 <td>Normal but significant condition.</td>
2919 <td>"httpd: caught SIGBUS, attempting to dump core in
2924 <td><code>info</code> </td>
2926 <td>Informational.</td>
2928 <td>"Server seems busy, (you may need to increase
2929 StartServers, or Min/MaxSpareServers)..."</td>
2933 <td><code>debug</code> </td>
2935 <td>Debug-level messages</td>
2937 <td>"Opening config file ..."</td>
2940 <td><code>trace1</code> </td>
2942 <td>Trace messages</td>
2944 <td>"proxy: FTP: control connection complete"</td>
2947 <td><code>trace2</code> </td>
2949 <td>Trace messages</td>
2951 <td>"proxy: CONNECT: sending the CONNECT request to the remote proxy"</td>
2954 <td><code>trace3</code> </td>
2956 <td>Trace messages</td>
2958 <td>"openssl: Handshake: start"</td>
2961 <td><code>trace4</code> </td>
2963 <td>Trace messages</td>
2965 <td>"read from buffered SSL brigade, mode 0, 17 bytes"</td>
2968 <td><code>trace5</code> </td>
2970 <td>Trace messages</td>
2972 <td>"map lookup FAILED: map=rewritemap key=keyname"</td>
2975 <td><code>trace6</code> </td>
2977 <td>Trace messages</td>
2979 <td>"cache lookup FAILED, forcing new map lookup"</td>
2982 <td><code>trace7</code> </td>
2984 <td>Trace messages, dumping large amounts of data</td>
2986 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2989 <td><code>trace8</code> </td>
2991 <td>Trace messages, dumping large amounts of data</td>
2993 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2997 <p>When a particular level is specified, messages from all
2998 other levels of higher significance will be reported as well.
2999 <em>E.g.</em>, when <code>LogLevel info</code> is specified,
3000 then messages with log levels of <code>notice</code> and
3001 <code>warn</code> will also be posted.</p>
3003 <p>Using a level of at least <code>crit</code> is
3008 <pre class="prettyprint lang-config">LogLevel notice</pre>
3011 <div class="note"><h3>Note</h3>
3012 <p>When logging to a regular file, messages of the level
3013 <code>notice</code> cannot be suppressed and thus are always
3014 logged. However, this doesn't apply when logging is done
3015 using <code>syslog</code>.</p>
3018 <p>Specifying a level without a module name will reset the level
3019 for all modules to that level. Specifying a level with a module
3020 name will set the level for that module only. It is possible to
3021 use the module source file name, the module identifier, or the
3022 module identifier with the trailing <code>_module</code> omitted
3023 as module specification. This means the following three specifications
3026 <pre class="prettyprint lang-config">LogLevel info ssl:warn
3027 LogLevel info mod_ssl.c:warn
3028 LogLevel info ssl_module:warn</pre>
3031 <p>It is also possible to change the level per directory:</p>
3033 <pre class="prettyprint lang-config">LogLevel info
3034 <Directory "/usr/local/apache/htdocs/app">
3036 </Directory></pre>
3040 Per directory loglevel configuration only affects messages that are
3041 logged after the request has been parsed and that are associated with
3042 the request. Log messages which are associated with the server or
3043 the connection are not affected. The latter can be influenced by the
3044 <code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code> directive,
3050 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
3051 <li><code class="directive"><a href="#errorlogformat">ErrorLogFormat</a></code></li>
3052 <li><code class="directive"><a href="#logleveloverride">LogLevelOverride</a></code></li>
3053 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
3056 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3057 <div class="directive-section"><h2><a name="LogLevelOverride" id="LogLevelOverride">LogLevelOverride</a> <a name="logleveloverride" id="logleveloverride">Directive</a></h2>
3058 <table class="directive">
3059 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Override the verbosity of the ErrorLog for certain clients</td></tr>
3060 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel <var>ipaddress</var>[/<var>prefixlen</var>]
3061 [<var>module</var>:]<var>level</var> [<var>module</var>:<var>level</var>] ...
3063 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>unset</code></td></tr>
3064 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3065 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3066 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3067 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.5.0 and later</td></tr>
3069 <p><code class="directive">LogLevelOverride</code> adjusts the
3070 <code class="directive"><a href="#loglevel">LogLevel</a></code> for requests coming from
3071 certain client IP addresses.
3072 This allows to enable verbose logging only for certain test clients.
3073 The IP address is checked at a very early state in the connection
3074 processing. Therefore, <code class="directive">LogLevelOverride</code> allows to
3075 change the log level for things like the SSL handshake which happen before
3076 a <code class="directive"><a href="#loglevel">LogLevel</a></code> directive in an
3077 <code class="directive"><a href="#if"><If></a></code> container would
3080 <p><code class="directive">LogLevelOverride</code> accepts either a single
3081 IP-address or a CIDR IP-address/len subnet specification.
3082 For the syntax of the loglevel specification, see the
3083 <code class="directive"><a href="#loglevel">LogLevel</a></code> directive.</p>
3085 <p>For requests that match a <code class="directive">LogLevelOverride</code>
3086 directive, per-directory specifications of
3087 <code class="directive"><a href="#loglevel">LogLevel</a></code> are ignored.</p>
3091 <pre class="prettyprint lang-config"> LogLevelOverride 192.0.2.0/24 ssl:trace6
3092 LogLevelOverride 192.0.2.7 ssl:trace8</pre>
3096 <code class="directive">LogLevelOverride</code> only affects
3097 log messages that are associated with the request or the connection.
3098 Log messages which are associated with the server are not affected.
3104 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
3107 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3108 <div class="directive-section"><h2><a name="MaxKeepAliveRequests" id="MaxKeepAliveRequests">MaxKeepAliveRequests</a> <a name="maxkeepaliverequests" id="maxkeepaliverequests">Directive</a></h2>
3109 <table class="directive">
3110 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of requests allowed on a persistent
3111 connection</td></tr>
3112 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxKeepAliveRequests <var>number</var></code></td></tr>
3113 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxKeepAliveRequests 100</code></td></tr>
3114 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3115 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3116 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3118 <p>The <code class="directive">MaxKeepAliveRequests</code> directive
3119 limits the number of requests allowed per connection when
3120 <code class="directive"><a href="#keepalive">KeepAlive</a></code> is on. If it is
3121 set to <code>0</code>, unlimited requests will be allowed. We
3122 recommend that this setting be kept to a high value for maximum
3123 server performance.</p>
3127 <pre class="prettyprint lang-config">MaxKeepAliveRequests 500</pre>
3131 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3132 <div class="directive-section"><h2><a name="MaxRangeOverlaps" id="MaxRangeOverlaps">MaxRangeOverlaps</a> <a name="maxrangeoverlaps" id="maxrangeoverlaps">Directive</a></h2>
3133 <table class="directive">
3134 <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
3136 <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>
3137 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeOverlaps 20</code></td></tr>
3138 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3139 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3140 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3141 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3143 <p>The <code class="directive">MaxRangeOverlaps</code> directive
3144 limits the number of overlapping HTTP ranges the server is willing to
3145 return to the client. If more overlapping ranges than permitted are requested,
3146 the complete resource is returned instead.</p>
3149 <dt><strong>default</strong></dt>
3150 <dd>Limits the number of overlapping ranges to a compile-time default of 20.</dd>
3152 <dt><strong>none</strong></dt>
3153 <dd>No overlapping Range headers are allowed.</dd>
3155 <dt><strong>unlimited</strong></dt>
3156 <dd>The server does not limit the number of overlapping ranges it is
3157 willing to satisfy.</dd>
3159 <dt><var>number-of-ranges</var></dt>
3160 <dd>A positive number representing the maximum number of overlapping ranges the
3161 server is willing to satisfy.</dd>
3165 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3166 <div class="directive-section"><h2><a name="MaxRangeReversals" id="MaxRangeReversals">MaxRangeReversals</a> <a name="maxrangereversals" id="maxrangereversals">Directive</a></h2>
3167 <table class="directive">
3168 <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
3170 <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>
3171 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeReversals 20</code></td></tr>
3172 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3173 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3174 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3175 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3177 <p>The <code class="directive">MaxRangeReversals</code> directive
3178 limits the number of HTTP Range reversals the server is willing to
3179 return to the client. If more ranges reversals than permitted are requested,
3180 the complete resource is returned instead.</p>
3183 <dt><strong>default</strong></dt>
3184 <dd>Limits the number of range reversals to a compile-time default of 20.</dd>
3186 <dt><strong>none</strong></dt>
3187 <dd>No Range reversals headers are allowed.</dd>
3189 <dt><strong>unlimited</strong></dt>
3190 <dd>The server does not limit the number of range reversals it is
3191 willing to satisfy.</dd>
3193 <dt><var>number-of-ranges</var></dt>
3194 <dd>A positive number representing the maximum number of range reversals the
3195 server is willing to satisfy.</dd>
3199 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3200 <div class="directive-section"><h2><a name="MaxRanges" id="MaxRanges">MaxRanges</a> <a name="maxranges" id="maxranges">Directive</a></h2>
3201 <table class="directive">
3202 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of ranges allowed before returning the complete
3204 <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>
3205 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRanges 200</code></td></tr>
3206 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3207 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3208 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3209 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3211 <p>The <code class="directive">MaxRanges</code> directive
3212 limits the number of HTTP ranges the server is willing to
3213 return to the client. If more ranges than permitted are requested,
3214 the complete resource is returned instead.</p>
3217 <dt><strong>default</strong></dt>
3218 <dd>Limits the number of ranges to a compile-time default of 200.</dd>
3220 <dt><strong>none</strong></dt>
3221 <dd>Range headers are ignored.</dd>
3223 <dt><strong>unlimited</strong></dt>
3224 <dd>The server does not limit the number of ranges it is
3225 willing to satisfy.</dd>
3227 <dt><var>number-of-ranges</var></dt>
3228 <dd>A positive number representing the maximum number of ranges the
3229 server is willing to satisfy.</dd>
3233 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3234 <div class="directive-section"><h2><a name="MergeTrailers" id="MergeTrailers">MergeTrailers</a> <a name="mergetrailers" id="mergetrailers">Directive</a></h2>
3235 <table class="directive">
3236 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines whether trailers are merged into headers</td></tr>
3237 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MergeTrailers [on|off]</code></td></tr>
3238 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MergeTrailers off</code></td></tr>
3239 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3240 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3241 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3242 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.4.11 and later</td></tr>
3244 <p>This directive controls whether HTTP trailers are copied into the
3245 internal representation of HTTP headers. This merging occurs when the
3246 request body has been completely consumed, long after most header
3247 processing would have a chance to examine or modify request headers.</p>
3248 <p>This option is provided for compatibility with releases prior to 2.4.11,
3249 where trailers were always merged.</p>
3252 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3253 <div class="directive-section"><h2><a name="Mutex" id="Mutex">Mutex</a> <a name="mutex" id="mutex">Directive</a></h2>
3254 <table class="directive">
3255 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures mutex mechanism and lock file directory for all
3256 or specified mutexes</td></tr>
3257 <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>
3258 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Mutex default</code></td></tr>
3259 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3260 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3261 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3262 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.4 and later</td></tr>
3264 <p>The <code class="directive">Mutex</code> directive sets the mechanism,
3265 and optionally the lock file location, that httpd and modules use
3266 to serialize access to resources. Specify <code>default</code> as
3267 the second argument to change the settings for all mutexes; specify
3268 a mutex name (see table below) as the second argument to override
3269 defaults only for that mutex.</p>
3271 <p>The <code class="directive">Mutex</code> directive is typically used in
3272 the following exceptional situations:</p>
3275 <li>change the mutex mechanism when the default mechanism selected
3276 by <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> has a functional or performance
3279 <li>change the directory used by file-based mutexes when the
3280 default directory does not support locking</li>
3283 <div class="note"><h3>Supported modules</h3>
3284 <p>This directive only configures mutexes which have been registered
3285 with the core server using the <code>ap_mutex_register()</code> API.
3286 All modules bundled with httpd support the <code class="directive">Mutex</code>
3287 directive, but third-party modules may not. Consult the documentation
3288 of the third-party module, which must indicate the mutex name(s) which
3289 can be configured if this directive is supported.</p>
3292 <p>The following mutex <em>mechanisms</em> are available:</p>
3294 <li><code>default | yes</code>
3295 <p>This selects the default locking implementation, as determined by
3296 <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a>. The default locking implementation can
3297 be displayed by running <code class="program"><a href="../programs/httpd.html">httpd</a></code> with the
3298 <code>-V</code> option.</p></li>
3300 <li><code>none | no</code>
3301 <p>This effectively disables the mutex, and is only allowed for a
3302 mutex if the module indicates that it is a valid choice. Consult the
3303 module documentation for more information.</p></li>
3305 <li><code>posixsem</code>
3306 <p>This is a mutex variant based on a Posix semaphore.</p>
3308 <div class="warning"><h3>Warning</h3>
3309 <p>The semaphore ownership is not recovered if a thread in the process
3310 holding the mutex segfaults, resulting in a hang of the web server.</p>
3314 <li><code>sysvsem</code>
3315 <p>This is a mutex variant based on a SystemV IPC semaphore.</p>
3317 <div class="warning"><h3>Warning</h3>
3318 <p>It is possible to "leak" SysV semaphores if processes crash
3319 before the semaphore is removed.</p>
3322 <div class="warning"><h3>Security</h3>
3323 <p>The semaphore API allows for a denial of service attack by any
3324 CGIs running under the same uid as the webserver (<em>i.e.</em>,
3325 all CGIs, unless you use something like <code class="program"><a href="../programs/suexec.html">suexec</a></code>
3326 or <code>cgiwrapper</code>).</p>
3330 <li><code>sem</code>
3331 <p>This selects the "best" available semaphore implementation, choosing
3332 between Posix and SystemV IPC semaphores, in that order.</p></li>
3334 <li><code>pthread</code>
3335 <p>This is a mutex variant based on cross-process Posix thread
3338 <div class="warning"><h3>Warning</h3>
3339 <p>On most systems, if a child process terminates abnormally while
3340 holding a mutex that uses this implementation, the server will deadlock
3341 and stop responding to requests. When this occurs, the server will
3342 require a manual restart to recover.</p>
3343 <p>Solaris is a notable exception as it provides a mechanism which
3344 usually allows the mutex to be recovered after a child process
3345 terminates abnormally while holding a mutex.</p>
3346 <p>If your system implements the
3347 <code>pthread_mutexattr_setrobust_np()</code> function, you may be able
3348 to use the <code>pthread</code> option safely.</p>
3352 <li><code>fcntl:/path/to/mutex</code>
3353 <p>This is a mutex variant where a physical (lock-)file and the
3354 <code>fcntl()</code> function are used as the mutex.</p>
3356 <div class="warning"><h3>Warning</h3>
3357 <p>When multiple mutexes based on this mechanism are used within
3358 multi-threaded, multi-process environments, deadlock errors (EDEADLK)
3359 can be reported for valid mutex operations if <code>fcntl()</code>
3360 is not thread-aware, such as on Solaris.</p>
3364 <li><code>flock:/path/to/mutex</code>
3365 <p>This is similar to the <code>fcntl:/path/to/mutex</code> method
3366 with the exception that the <code>flock()</code> function is used to
3367 provide file locking.</p></li>
3369 <li><code>file:/path/to/mutex</code>
3370 <p>This selects the "best" available file locking implementation,
3371 choosing between <code>fcntl</code> and <code>flock</code>, in that
3375 <p>Most mechanisms are only available on selected platforms, where the
3376 underlying platform and <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> support it. Mechanisms
3377 which aren't available on all platforms are <em>posixsem</em>,
3378 <em>sysvsem</em>, <em>sem</em>, <em>pthread</em>, <em>fcntl</em>,
3379 <em>flock</em>, and <em>file</em>.</p>
3381 <p>With the file-based mechanisms <em>fcntl</em> and <em>flock</em>,
3382 the path, if provided, is a directory where the lock file will be created.
3383 The default directory is httpd's run-time file directory,
3384 <code class="directive"><a href="#defaultruntimedir">DefaultRuntimeDir</a></code>. If a relative
3385 path is provided, it is relative to
3386 <code class="directive"><a href="#defaultruntimedir">DefaultRuntimeDir</a></code>. Always use a local
3387 disk filesystem for <code>/path/to/mutex</code> and never a directory residing
3388 on a NFS- or AFS-filesystem. The basename of the file will be the mutex
3389 type, an optional instance string provided by the module, and unless the
3390 <code>OmitPID</code> keyword is specified, the process id of the httpd
3391 parent process will be appended to make the file name unique, avoiding
3392 conflicts when multiple httpd instances share a lock file directory. For
3393 example, if the mutex name is <code>mpm-accept</code> and the lock file
3394 directory is <code>/var/httpd/locks</code>, the lock file name for the
3395 httpd instance with parent process id 12345 would be
3396 <code>/var/httpd/locks/mpm-accept.12345</code>.</p>
3398 <div class="warning"><h3>Security</h3>
3399 <p>It is best to <em>avoid</em> putting mutex files in a world-writable
3400 directory such as <code>/var/tmp</code> because someone could create
3401 a denial of service attack and prevent the server from starting by
3402 creating a lockfile with the same name as the one the server will try
3406 <p>The following table documents the names of mutexes used by httpd
3407 and bundled modules.</p>
3409 <table class="bordered"><tr class="header">
3412 <th>Protected resource</th>
3415 <td><code>mpm-accept</code></td>
3416 <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>
3417 <td>incoming connections, to avoid the thundering herd problem;
3418 for more information, refer to the
3419 <a href="../misc/perf-tuning.html">performance tuning</a>
3423 <td><code>authdigest-client</code></td>
3424 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3425 <td>client list in shared memory</td>
3428 <td><code>authdigest-opaque</code></td>
3429 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3430 <td>counter in shared memory</td>
3433 <td><code>ldap-cache</code></td>
3434 <td><code class="module"><a href="../mod/mod_ldap.html">mod_ldap</a></code></td>
3435 <td>LDAP result cache</td>
3438 <td><code>rewrite-map</code></td>
3439 <td><code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code></td>
3440 <td>communication with external mapping programs, to avoid
3441 intermixed I/O from multiple requests</td>
3444 <td><code>ssl-cache</code></td>
3445 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3446 <td>SSL session cache</td>
3449 <td><code>ssl-stapling</code></td>
3450 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3451 <td>OCSP stapling response cache</td>
3454 <td><code>watchdog-callback</code></td>
3455 <td><code class="module"><a href="../mod/mod_watchdog.html">mod_watchdog</a></code></td>
3456 <td>callback function of a particular client module</td>
3460 <p>The <code>OmitPID</code> keyword suppresses the addition of the httpd
3461 parent process id from the lock file name.</p>
3463 <p>In the following example, the mutex mechanism for the MPM accept
3464 mutex will be changed from the compiled-in default to <code>fcntl</code>,
3465 with the associated lock file created in directory
3466 <code>/var/httpd/locks</code>. The mutex mechanism for all other mutexes
3467 will be changed from the compiled-in default to <code>sysvsem</code>.</p>
3469 <pre class="prettyprint lang-config">Mutex sysvsem default
3470 Mutex fcntl:/var/httpd/locks mpm-accept</pre>
3474 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3475 <div class="directive-section"><h2><a name="NameVirtualHost" id="NameVirtualHost">NameVirtualHost</a> <a name="namevirtualhost" id="namevirtualhost">Directive</a></h2>
3476 <table class="directive">
3477 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>DEPRECATED: Designates an IP address for name-virtual
3479 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NameVirtualHost <var>addr</var>[:<var>port</var>]</code></td></tr>
3480 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3481 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3482 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3485 <p>Prior to 2.3.11, <code class="directive">NameVirtualHost</code> was required
3486 to instruct the server that a particular IP address and port combination
3487 was usable as a name-based virtual host. In 2.3.11 and later,
3488 any time an IP address and port combination is used in multiple virtual
3489 hosts, name-based virtual hosting is automatically enabled for that address.</p>
3491 <p>This directive currently has no effect.</p>
3495 <li><a href="../vhosts/">Virtual Hosts
3496 documentation</a></li>
3499 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3500 <div class="directive-section"><h2><a name="Options" id="Options">Options</a> <a name="options" id="options">Directive</a></h2>
3501 <table class="directive">
3502 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures what features are available in a particular
3504 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Options
3505 [+|-]<var>option</var> [[+|-]<var>option</var>] ...</code></td></tr>
3506 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Options FollowSymlinks</code></td></tr>
3507 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3508 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
3509 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3510 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3511 <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>
3513 <p>The <code class="directive">Options</code> directive controls which
3514 server features are available in a particular directory.</p>
3516 <p><var>option</var> can be set to <code>None</code>, in which
3517 case none of the extra features are enabled, or one or more of
3521 <dt><code>All</code></dt>
3523 <dd>All options except for <code>MultiViews</code>.</dd>
3525 <dt><code>ExecCGI</code></dt>
3528 Execution of CGI scripts using <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>
3531 <dt><code>FollowSymLinks</code></dt>
3534 The server will follow symbolic links in this directory. This is
3535 the default setting.
3537 <p>Even though the server follows the symlink it does <em>not</em>
3538 change the pathname used to match against <code class="directive"><a href="#directory"><Directory></a></code> sections.</p>
3540 <p>The <code>FollowSymLinks</code> and
3541 <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
3542 <code>.htaccess</code> files.</p>
3544 <p>Omitting this option should not be considered a security restriction,
3545 since symlink testing is subject to race conditions that make it
3549 <dt><code>Includes</code></dt>
3552 Server-side includes provided by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
3555 <dt><code>IncludesNOEXEC</code></dt>
3559 Server-side includes are permitted, but the <code>#exec
3560 cmd</code> and <code>#exec cgi</code> are disabled. It is still
3561 possible to <code>#include virtual</code> CGI scripts from
3562 <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>ed
3565 <dt><code>Indexes</code></dt>
3568 If a URL which maps to a directory is requested and there
3569 is no <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
3570 (<em>e.g.</em>, <code>index.html</code>) in that directory, then
3571 <code class="module"><a href="../mod/mod_autoindex.html">mod_autoindex</a></code> will return a formatted listing
3572 of the directory.</dd>
3574 <dt><code>MultiViews</code></dt>
3577 <a href="../content-negotiation.html">Content negotiated</a>
3578 "MultiViews" are allowed using
3579 <code class="module"><a href="../mod/mod_negotiation.html">mod_negotiation</a></code>.
3580 <div class="note"><h3>Note</h3> <p>This option gets ignored if set
3581 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>
3582 needs real resources to compare against and evaluate from.</p></div>
3585 <dt><code>SymLinksIfOwnerMatch</code></dt>
3587 <dd>The server will only follow symbolic links for which the
3588 target file or directory is owned by the same user id as the
3591 <div class="note"><h3>Note</h3>
3592 <p>The <code>FollowSymLinks</code> and
3593 <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
3594 <code>.htaccess</code> files.</p>
3596 <p>This option should not be considered a security restriction,
3597 since symlink testing is subject to race conditions that make it
3602 <p>Normally, if multiple <code class="directive">Options</code> could
3603 apply to a directory, then the most specific one is used and
3604 others are ignored; the options are not merged. (See <a href="../sections.html#mergin">how sections are merged</a>.)
3605 However if <em>all</em> the options on the
3606 <code class="directive">Options</code> directive are preceded by a
3607 <code>+</code> or <code>-</code> symbol, the options are
3608 merged. Any options preceded by a <code>+</code> are added to the
3609 options currently in force, and any options preceded by a
3610 <code>-</code> are removed from the options currently in
3613 <div class="note"><h3>Note</h3>
3614 <p>Mixing <code class="directive">Options</code> with a <code>+</code> or
3615 <code>-</code> with those without is not valid syntax and will be
3616 rejected during server startup by the syntax check with an abort.</p>
3619 <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>
3621 <pre class="prettyprint lang-config"><Directory "/web/docs">
3622 Options Indexes FollowSymLinks
3625 <Directory "/web/docs/spec">
3627 </Directory></pre>
3630 <p>then only <code>Includes</code> will be set for the
3631 <code>/web/docs/spec</code> directory. However if the second
3632 <code class="directive">Options</code> directive uses the <code>+</code> and
3633 <code>-</code> symbols:</p>
3635 <pre class="prettyprint lang-config"><Directory "/web/docs">
3636 Options Indexes FollowSymLinks
3639 <Directory "/web/docs/spec">
3640 Options +Includes -Indexes
3641 </Directory></pre>
3644 <p>then the options <code>FollowSymLinks</code> and
3645 <code>Includes</code> are set for the <code>/web/docs/spec</code>
3648 <div class="note"><h3>Note</h3>
3649 <p>Using <code>-IncludesNOEXEC</code> or
3650 <code>-Includes</code> disables server-side includes completely
3651 regardless of the previous setting.</p>
3654 <p>The default in the absence of any other settings is
3655 <code>FollowSymlinks</code>.</p>
3658 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3659 <div class="directive-section"><h2><a name="Protocol" id="Protocol">Protocol</a> <a name="protocol" id="protocol">Directive</a></h2>
3660 <table class="directive">
3661 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Protocol for a listening socket</td></tr>
3662 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Protocol <var>protocol</var></code></td></tr>
3663 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3664 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3665 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3666 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>On Windows, only available from Apache 2.3.3 and later.</td></tr>
3668 <p>This directive specifies the protocol used for a specific listening socket.
3669 The protocol is used to determine which module should handle a request and
3670 to apply protocol specific optimizations with the <code class="directive">AcceptFilter</code>
3673 <p>You only need to set the protocol if you are running on non-standard ports;
3674 otherwise, <code>http</code> is assumed for port 80 and <code>https</code>
3677 <p>For example, if you are running <code>https</code> on a non-standard port,
3678 specify the protocol explicitly:</p>
3680 <pre class="prettyprint lang-config">Protocol https</pre>
3683 <p>You can also specify the protocol using the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code> directive.</p>
3687 <li><code class="directive"><a href="#acceptfilter">AcceptFilter</a></code></li>
3688 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
3691 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3692 <div class="directive-section"><h2><a name="Protocols" id="Protocols">Protocols</a> <a name="protocols" id="protocols">Directive</a></h2>
3693 <table class="directive">
3694 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Protocols available for a server/virtual host</td></tr>
3695 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Protocols <var>protocol</var> ...</code></td></tr>
3696 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Protocols http/1.1</code></td></tr>
3697 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3698 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3699 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3700 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Only available from Apache 2.4.17 and later.</td></tr>
3702 <p>This directive specifies the list of protocols supported for a
3703 server/virtual host. The list determines the allowed protocols
3704 a client may negotiate for this server/host.</p>
3706 <p>You need to set protocols if you want to extend the available
3707 protocols for a server/host. By default, only the http/1.1 protocol
3708 (which includes the compatibility with 1.0 and 0.9 clients) is
3711 <p>For example, if you want to support HTTP/2 for a server with TLS,
3714 <pre class="prettyprint lang-config">Protocols h2 http/1.1</pre>
3717 <p>Valid protocols are <code>http/1.1</code> for http and https connections,
3718 <code>h2</code> on https connections and <code>h2c</code> for http
3719 connections. Modules may enable more protocols.</p>
3721 <p>It is safe to specify protocols that are unavailable/disabled. Such
3722 protocol names will simply be ignored.</p>
3724 <p>Protocols specified in base servers are inherited for virtual hosts
3725 only if the virtual host has no own Protocols directive. Or, the other
3726 way around, Protocols directives in virtual hosts replace any
3727 such directive in the base server.
3733 <li><code class="directive"><a href="#protocolshonororder">ProtocolsHonorOrder</a></code></li>
3736 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3737 <div class="directive-section"><h2><a name="ProtocolsHonorOrder" id="ProtocolsHonorOrder">ProtocolsHonorOrder</a> <a name="protocolshonororder" id="protocolshonororder">Directive</a></h2>
3738 <table class="directive">
3739 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines if order of Protocols determines precedence during negotiation</td></tr>
3740 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProtocolsHonorOrder On|Off</code></td></tr>
3741 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProtocolsHonorOrder On</code></td></tr>
3742 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3743 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3744 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3745 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Only available from Apache 2.4.17 and later.</td></tr>
3747 <p>This directive specifies if the server should honor the order in which
3748 the <code class="directive">Protocols</code> directive lists protocols.</p>
3750 <p>If configured Off, the client supplied list order of protocols has
3751 precedence over the order in the server configuration.</p>
3753 <p>With <code class="directive">ProtocolsHonorOrder</code> set to <code>on</code>
3754 (default), the client ordering does not matter and only the ordering
3755 in the server settings influences the outcome of the protocol
3761 <li><code class="directive"><a href="#protocols">Protocols</a></code></li>
3764 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3765 <div class="directive-section"><h2><a name="RegisterHttpMethod" id="RegisterHttpMethod">RegisterHttpMethod</a> <a name="registerhttpmethod" id="registerhttpmethod">Directive</a></h2>
3766 <table class="directive">
3767 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Register non-standard HTTP methods</td></tr>
3768 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>RegisterHttpMethod <var>method</var> [<var>method</var> [...]]</code></td></tr>
3769 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3770 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3771 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3773 <p>HTTP Methods that are not conforming to the relvant RFCs are normally
3774 rejected by request processing in Apache HTTPD. To avoid this, modules
3775 can register non-standard HTTP methods they support.
3776 The <code class="directive">RegisterHttpMethod</code> allows to register such
3777 methods manually. This can be useful if such methods are forwarded
3778 for external processing, e.g. to a CGI script.</p>
3781 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3782 <div class="directive-section"><h2><a name="RLimitCPU" id="RLimitCPU">RLimitCPU</a> <a name="rlimitcpu" id="rlimitcpu">Directive</a></h2>
3783 <table class="directive">
3784 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the CPU consumption of processes launched
3785 by Apache httpd children</td></tr>
3786 <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>
3787 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3788 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3789 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3790 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3791 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3793 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3794 resource limit for all processes and the second parameter sets
3795 the maximum resource limit. Either parameter can be a number,
3796 or <code>max</code> to indicate to the server that the limit should
3797 be set to the maximum allowed by the operating system
3798 configuration. Raising the maximum resource limit requires that
3799 the server is running as <code>root</code> or in the initial startup
3802 <p>This applies to processes forked from Apache httpd children
3803 servicing requests, not the Apache httpd children themselves. This
3804 includes CGI scripts and SSI exec commands, but not any
3805 processes forked from the Apache httpd parent, such as piped
3808 <p>CPU resource limits are expressed in seconds per
3813 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3814 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3817 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3818 <div class="directive-section"><h2><a name="RLimitMEM" id="RLimitMEM">RLimitMEM</a> <a name="rlimitmem" id="rlimitmem">Directive</a></h2>
3819 <table class="directive">
3820 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the memory consumption of processes launched
3821 by Apache httpd children</td></tr>
3822 <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>
3823 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3824 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3825 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3826 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3827 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3829 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3830 resource limit for all processes and the second parameter sets
3831 the maximum resource limit. Either parameter can be a number,
3832 or <code>max</code> to indicate to the server that the limit should
3833 be set to the maximum allowed by the operating system
3834 configuration. Raising the maximum resource limit requires that
3835 the server is running as <code>root</code> or in the initial startup
3838 <p>This applies to processes forked from Apache httpd children
3839 servicing requests, not the Apache httpd children themselves. This
3840 includes CGI scripts and SSI exec commands, but not any
3841 processes forked from the Apache httpd parent, such as piped
3844 <p>Memory resource limits are expressed in bytes per
3849 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3850 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3853 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3854 <div class="directive-section"><h2><a name="RLimitNPROC" id="RLimitNPROC">RLimitNPROC</a> <a name="rlimitnproc" id="rlimitnproc">Directive</a></h2>
3855 <table class="directive">
3856 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of processes that can be launched by
3857 processes launched by Apache httpd children</td></tr>
3858 <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>
3859 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3860 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3861 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3862 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3863 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3865 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3866 resource limit for all processes, and the second parameter sets
3867 the maximum resource limit. Either parameter can be a number,
3868 or <code>max</code> to indicate to the server that the limit
3869 should be set to the maximum allowed by the operating system
3870 configuration. Raising the maximum resource limit requires that
3871 the server is running as <code>root</code> or in the initial startup
3874 <p>This applies to processes forked from Apache httpd children
3875 servicing requests, not the Apache httpd children themselves. This
3876 includes CGI scripts and SSI exec commands, but not any
3877 processes forked from the Apache httpd parent, such as piped
3880 <p>Process limits control the number of processes per user.</p>
3882 <div class="note"><h3>Note</h3>
3883 <p>If CGI processes are <strong>not</strong> running
3884 under user ids other than the web server user id, this directive
3885 will limit the number of processes that the server itself can
3886 create. Evidence of this situation will be indicated by
3887 <strong><code>cannot fork</code></strong> messages in the
3888 <code>error_log</code>.</p>
3893 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3894 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3897 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3898 <div class="directive-section"><h2><a name="ScriptInterpreterSource" id="ScriptInterpreterSource">ScriptInterpreterSource</a> <a name="scriptinterpretersource" id="scriptinterpretersource">Directive</a></h2>
3899 <table class="directive">
3900 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
3902 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ScriptInterpreterSource Registry|Registry-Strict|Script</code></td></tr>
3903 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ScriptInterpreterSource Script</code></td></tr>
3904 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3905 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3906 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3907 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3908 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Win32 only.</td></tr>
3910 <p>This directive is used to control how Apache httpd finds the
3911 interpreter used to run CGI scripts. The default setting is
3912 <code>Script</code>. This causes Apache httpd to use the interpreter pointed to
3913 by the shebang line (first line, starting with <code>#!</code>) in the
3914 script. On Win32 systems this line usually looks like:</p>
3916 <pre class="prettyprint lang-perl">#!C:/Perl/bin/perl.exe</pre>
3919 <p>or, if <code>perl</code> is in the <code>PATH</code>, simply:</p>
3921 <pre class="prettyprint lang-perl">#!perl</pre>
3924 <p>Setting <code>ScriptInterpreterSource Registry</code> will
3925 cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
3926 searched using the script file extension (e.g., <code>.pl</code>) as a
3927 search key. The command defined by the registry subkey
3928 <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
3929 <code>Shell\Open\Command</code> is used to open the script file. If the
3930 registry keys cannot be found, Apache httpd falls back to the behavior of the
3931 <code>Script</code> option.</p>
3933 <div class="warning"><h3>Security</h3>
3934 <p>Be careful when using <code>ScriptInterpreterSource
3935 Registry</code> with <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>'ed directories, because
3936 Apache httpd will try to execute <strong>every</strong> file within this
3937 directory. The <code>Registry</code> setting may cause undesired
3938 program calls on files which are typically not executed. For
3939 example, the default open command on <code>.htm</code> files on
3940 most Windows systems will execute Microsoft Internet Explorer, so
3941 any HTTP request for an <code>.htm</code> file existing within the
3942 script directory would start the browser in the background on the
3943 server. This is a good way to crash your system within a minute or
3947 <p>The option <code>Registry-Strict</code> which is new in Apache HTTP Server
3948 2.0 does the same thing as <code>Registry</code> but uses only the
3949 subkey <code>Shell\ExecCGI\Command</code>. The
3950 <code>ExecCGI</code> key is not a common one. It must be
3951 configured manually in the windows registry and hence prevents
3952 accidental program calls on your system.</p>
3955 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3956 <div class="directive-section"><h2><a name="SeeRequestTail" id="SeeRequestTail">SeeRequestTail</a> <a name="seerequesttail" id="seerequesttail">Directive</a></h2>
3957 <table class="directive">
3958 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine if mod_status displays the first 63 characters
3959 of a request or the last 63, assuming the request itself is greater than
3961 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SeeRequestTail On|Off</code></td></tr>
3962 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SeeRequestTail Off</code></td></tr>
3963 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3964 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3965 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3967 <p>mod_status with <code>ExtendedStatus On</code>
3968 displays the actual request being handled.
3969 For historical purposes, only 63 characters of the request
3970 are actually stored for display purposes. This directive
3971 controls whether the 1st 63 characters are stored (the previous
3972 behavior and the default) or if the last 63 characters are. This
3973 is only applicable, of course, if the length of the request is
3974 64 characters or greater.</p>
3976 <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:
3979 <table class="bordered">
3981 <th>Off (default)</th>
3982 <td>GET /disk1/storage/apache/htdocs/images/imagestore1/food/apples</td>
3986 <td>orage/apache/htdocs/images/imagestore1/food/apples.jpg HTTP/1.1</td>
3992 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3993 <div class="directive-section"><h2><a name="ServerAdmin" id="ServerAdmin">ServerAdmin</a> <a name="serveradmin" id="serveradmin">Directive</a></h2>
3994 <table class="directive">
3995 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Email address that the server includes in error
3996 messages sent to the client</td></tr>
3997 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAdmin <var>email-address</var>|<var>URL</var></code></td></tr>
3998 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3999 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4000 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4002 <p>The <code class="directive">ServerAdmin</code> sets the contact address
4003 that the server includes in any error messages it returns to the
4004 client. If the <code>httpd</code> doesn't recognize the supplied argument
4006 assumes, that it's an <var>email-address</var> and prepends it with
4007 <code>mailto:</code> in hyperlink targets. However, it's recommended to
4008 actually use an email address, since there are a lot of CGI scripts that
4009 make that assumption. If you want to use an URL, it should point to another
4010 server under your control. Otherwise users may not be able to contact you in
4013 <p>It may be worth setting up a dedicated address for this, e.g.</p>
4015 <pre class="prettyprint lang-config">ServerAdmin www-admin@foo.example.com</pre>
4017 <p>as users do not always mention that they are talking about the
4021 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4022 <div class="directive-section"><h2><a name="ServerAlias" id="ServerAlias">ServerAlias</a> <a name="serveralias" id="serveralias">Directive</a></h2>
4023 <table class="directive">
4024 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Alternate names for a host used when matching requests
4025 to name-virtual hosts</td></tr>
4026 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</code></td></tr>
4027 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
4028 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4029 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4031 <p>The <code class="directive">ServerAlias</code> directive sets the
4032 alternate names for a host, for use with <a href="../vhosts/name-based.html">name-based virtual hosts</a>. The
4033 <code class="directive">ServerAlias</code> may include wildcards, if appropriate.</p>
4035 <pre class="prettyprint lang-config"><VirtualHost *:80>
4036 ServerName server.example.com
4037 ServerAlias server server2.example.com server2
4038 ServerAlias *.example.com
4039 UseCanonicalName Off
4041 </VirtualHost></pre>
4044 <p>Name-based virtual hosts for the best-matching set of <code class="directive"><a href="#virtualhost"><virtualhost></a></code>s are processed
4045 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
4046 (nor for ServerName vs. ServerAlias). </p>
4048 <p>The complete list of names in the <code class="directive">VirtualHost</code>
4049 directive are treated just like a (non wildcard)
4050 <code class="directive">ServerAlias</code>.</p>
4055 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
4056 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4059 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4060 <div class="directive-section"><h2><a name="ServerName" id="ServerName">ServerName</a> <a name="servername" id="servername">Directive</a></h2>
4061 <table class="directive">
4062 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hostname and port that the server uses to identify
4064 <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>
4065 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4066 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4067 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4069 <p>The <code class="directive">ServerName</code> directive sets the
4070 request scheme, hostname and
4071 port that the server uses to identify itself. This is used when
4072 creating redirection URLs.</p>
4074 <p>Additionally, <code class="directive">ServerName</code> is used (possibly
4075 in conjunction with <code class="directive">ServerAlias</code>) to uniquely
4076 identify a virtual host, when using <a href="../vhosts/name-based.html">name-based virtual hosts</a>.</p>
4078 <p>For example, if the name of the
4079 machine hosting the web server is <code>simple.example.com</code>,
4080 but the machine also has the DNS alias <code>www.example.com</code>
4081 and you wish the web server to be so identified, the following
4082 directive should be used:</p>
4084 <pre class="prettyprint lang-config">ServerName www.example.com</pre>
4087 <p>The <code class="directive">ServerName</code> directive
4088 may appear anywhere within the definition of a server. However,
4089 each appearance overrides the previous appearance (within that
4092 <p>If no <code class="directive">ServerName</code> is specified, then the
4093 server attempts to deduce the client visible hostname by performing a
4094 reverse lookup on an IP address of the systems hostname.</p>
4096 <p>If no port is specified in the
4097 <code class="directive">ServerName</code>, then the server will use the
4098 port from the incoming request. For optimal reliability and
4099 predictability, you should specify an explicit hostname and port
4100 using the <code class="directive">ServerName</code> directive.</p>
4102 <p>If you are using <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
4103 the <code class="directive">ServerName</code> inside a
4104 <code class="directive"><a href="#virtualhost"><VirtualHost></a></code>
4105 section specifies what hostname must appear in the request's
4106 <code>Host:</code> header to match this virtual host.</p>
4108 <p>Sometimes, the server runs behind a device that processes SSL,
4109 such as a reverse proxy, load balancer or SSL offload
4110 appliance. When this is the case, specify the
4111 <code>https://</code> scheme and the port number to which the
4112 clients connect in the <code class="directive">ServerName</code> directive
4113 to make sure that the server generates the correct
4114 self-referential URLs.
4117 <p>See the description of the
4118 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> and
4119 <code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code> directives for
4120 settings which determine whether self-referential URLs (e.g., by the
4121 <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> module) will refer to the
4122 specified port, or to the port number given in the client's request.
4125 <div class="warning">
4126 <p>Failure to set <code class="directive">ServerName</code> to a name that
4127 your server can resolve to an IP address will result in a startup
4128 warning. <code>httpd</code> will then use whatever hostname it can
4129 determine, using the system's <code>hostname</code> command. This
4130 will almost never be the hostname you actually want.</p>
4131 <div class="example"><p><code>
4132 httpd: Could not reliably determine the server's fully qualified domain name, using rocinante.local for ServerName
4139 <li><a href="../dns-caveats.html">Issues Regarding DNS and
4140 Apache HTTP Server</a></li>
4141 <li><a href="../vhosts/">Apache HTTP Server virtual host
4142 documentation</a></li>
4143 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
4144 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
4145 <li><code class="directive"><a href="#serveralias">ServerAlias</a></code></li>
4148 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4149 <div class="directive-section"><h2><a name="ServerPath" id="ServerPath">ServerPath</a> <a name="serverpath" id="serverpath">Directive</a></h2>
4150 <table class="directive">
4151 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Legacy URL pathname for a name-based virtual host that
4152 is accessed by an incompatible browser</td></tr>
4153 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerPath <var>URL-path</var></code></td></tr>
4154 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
4155 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4156 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4158 <p>The <code class="directive">ServerPath</code> directive sets the legacy
4159 URL pathname for a host, for use with <a href="../vhosts/">name-based virtual hosts</a>.</p>
4163 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4166 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4167 <div class="directive-section"><h2><a name="ServerRoot" id="ServerRoot">ServerRoot</a> <a name="serverroot" id="serverroot">Directive</a></h2>
4168 <table class="directive">
4169 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server installation</td></tr>
4170 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerRoot <var>directory-path</var></code></td></tr>
4171 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerRoot /usr/local/apache</code></td></tr>
4172 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4173 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4174 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4176 <p>The <code class="directive">ServerRoot</code> directive sets the
4177 directory in which the server lives. Typically it will contain the
4178 subdirectories <code>conf/</code> and <code>logs/</code>. Relative
4179 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
4180 relative to this directory.</p>
4182 <pre class="prettyprint lang-config">ServerRoot "/home/httpd"</pre>
4185 <p>The default location of <code class="directive">ServerRoot</code> may be
4186 modified by using the <code>--prefix</code> argument to
4187 <a href="../programs/configure.html"><code>configure</code></a>, and
4188 most third-party distributions of the server have a different
4189 default location from the one listed above.</p>
4194 <li><a href="../invoking.html">the <code>-d</code>
4195 option to <code>httpd</code></a></li>
4196 <li><a href="../misc/security_tips.html#serverroot">the
4197 security tips</a> for information on how to properly set
4198 permissions on the <code class="directive">ServerRoot</code></li>
4201 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4202 <div class="directive-section"><h2><a name="ServerSignature" id="ServerSignature">ServerSignature</a> <a name="serversignature" id="serversignature">Directive</a></h2>
4203 <table class="directive">
4204 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the footer on server-generated documents</td></tr>
4205 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerSignature On|Off|EMail</code></td></tr>
4206 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerSignature Off</code></td></tr>
4207 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4208 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
4209 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4210 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4212 <p>The <code class="directive">ServerSignature</code> directive allows the
4213 configuration of a trailing footer line under server-generated
4214 documents (error messages, <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> ftp directory
4215 listings, <code class="module"><a href="../mod/mod_info.html">mod_info</a></code> output, ...). The reason why you
4216 would want to enable such a footer line is that in a chain of proxies,
4217 the user often has no possibility to tell which of the chained servers
4218 actually produced a returned error message.</p>
4220 <p>The <code>Off</code>
4221 setting, which is the default, suppresses the footer line (and is
4222 therefore compatible with the behavior of Apache-1.2 and
4223 below). The <code>On</code> setting simply adds a line with the
4224 server version number and <code class="directive"><a href="#servername">ServerName</a></code> of the serving virtual host,
4225 and the <code>EMail</code> setting additionally creates a
4226 "mailto:" reference to the <code class="directive"><a href="#serveradmin">ServerAdmin</a></code> of the referenced
4229 <p>After version 2.0.44, the details of the server version number
4230 presented are controlled by the <code class="directive"><a href="#servertokens">ServerTokens</a></code> directive.</p>
4234 <li><code class="directive"><a href="#servertokens">ServerTokens</a></code></li>
4237 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4238 <div class="directive-section"><h2><a name="ServerTokens" id="ServerTokens">ServerTokens</a> <a name="servertokens" id="servertokens">Directive</a></h2>
4239 <table class="directive">
4240 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the <code>Server</code> HTTP response
4242 <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>
4243 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerTokens Full</code></td></tr>
4244 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4245 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4246 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4248 <p>This directive controls whether <code>Server</code> response
4249 header field which is sent back to clients includes a
4250 description of the generic OS-type of the server as well as
4251 information about compiled-in modules.</p>
4254 <dt><code>ServerTokens Full</code> (or not specified)</dt>
4256 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4257 (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
4259 <dt><code>ServerTokens Prod[uctOnly]</code></dt>
4261 <dd>Server sends (<em>e.g.</em>): <code>Server:
4264 <dt><code>ServerTokens Major</code></dt>
4266 <dd>Server sends (<em>e.g.</em>): <code>Server:
4267 Apache/2</code></dd>
4269 <dt><code>ServerTokens Minor</code></dt>
4271 <dd>Server sends (<em>e.g.</em>): <code>Server:
4272 Apache/2.4</code></dd>
4274 <dt><code>ServerTokens Min[imal]</code></dt>
4276 <dd>Server sends (<em>e.g.</em>): <code>Server:
4277 Apache/2.4.2</code></dd>
4279 <dt><code>ServerTokens OS</code></dt>
4281 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4286 <p>This setting applies to the entire server, and cannot be
4287 enabled or disabled on a virtualhost-by-virtualhost basis.</p>
4289 <p>After version 2.0.44, this directive also controls the
4290 information presented by the <code class="directive"><a href="#serversignature">ServerSignature</a></code> directive.</p>
4292 <div class="note">Setting <code class="directive">ServerTokens</code> to less than
4293 <code>minimal</code> is not recommended because it makes it more
4294 difficult to debug interoperational problems. Also note that
4295 disabling the Server: header does nothing at all to make your
4296 server more secure. The idea of "security through obscurity"
4297 is a myth and leads to a false sense of safety.</div>
4301 <li><code class="directive"><a href="#serversignature">ServerSignature</a></code></li>
4304 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4305 <div class="directive-section"><h2><a name="SetHandler" id="SetHandler">SetHandler</a> <a name="sethandler" id="sethandler">Directive</a></h2>
4306 <table class="directive">
4307 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be processed by a
4309 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetHandler <var>handler-name</var>|None</code></td></tr>
4310 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4311 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4312 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4313 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4315 <p>When placed into an <code>.htaccess</code> file or a
4316 <code class="directive"><a href="#directory"><Directory></a></code> or
4317 <code class="directive"><a href="#location"><Location></a></code>
4318 section, this directive forces all matching files to be parsed
4319 through the <a href="../handler.html">handler</a> given by
4320 <var>handler-name</var>. For example, if you had a directory you
4321 wanted to be parsed entirely as imagemap rule files, regardless
4322 of extension, you might put the following into an
4323 <code>.htaccess</code> file in that directory:</p>
4325 <pre class="prettyprint lang-config">SetHandler imap-file</pre>
4328 <p>Another example: if you wanted to have the server display a
4329 status report whenever a URL of
4330 <code>http://servername/status</code> was called, you might put
4331 the following into <code>httpd.conf</code>:</p>
4333 <pre class="prettyprint lang-config"><Location "/status">
4334 SetHandler server-status
4335 </Location></pre>
4338 <p>You could also use this directive to configure a particular
4339 handler for files with a particular file extension. For example:</p>
4341 <pre class="prettyprint lang-config"><FilesMatch "\.php$">
4342 SetHandler application/x-httpd-php
4343 </FilesMatch></pre>
4346 <p>You can override an earlier defined <code class="directive">SetHandler</code>
4347 directive by using the value <code>None</code>.</p>
4349 <div class="note"><h3>Note</h3>
4350 <p>Because <code class="directive">SetHandler</code> overrides default handlers,
4351 normal behavior such as handling of URLs ending in a slash (/) as
4352 directories or index files is suppressed.</p></div>
4356 <li><code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code></li>
4359 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4360 <div class="directive-section"><h2><a name="SetInputFilter" id="SetInputFilter">SetInputFilter</a> <a name="setinputfilter" id="setinputfilter">Directive</a></h2>
4361 <table class="directive">
4362 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process client requests and POST
4364 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetInputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4365 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4366 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4367 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4368 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4370 <p>The <code class="directive">SetInputFilter</code> directive sets the
4371 filter or filters which will process client requests and POST
4372 input when they are received by the server. This is in addition to
4373 any filters defined elsewhere, including the
4374 <code class="directive"><a href="../mod/mod_mime.html#addinputfilter">AddInputFilter</a></code>
4377 <p>If more than one filter is specified, they must be separated
4378 by semicolons in the order in which they should process the
4383 <li><a href="../filter.html">Filters</a> documentation</li>
4386 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4387 <div class="directive-section"><h2><a name="SetOutputFilter" id="SetOutputFilter">SetOutputFilter</a> <a name="setoutputfilter" id="setoutputfilter">Directive</a></h2>
4388 <table class="directive">
4389 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process responses from the
4391 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4392 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4393 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4394 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4395 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4397 <p>The <code class="directive">SetOutputFilter</code> directive sets the filters
4398 which will process responses from the server before they are
4399 sent to the client. This is in addition to any filters defined
4400 elsewhere, including the
4401 <code class="directive"><a href="../mod/mod_mime.html#addoutputfilter">AddOutputFilter</a></code>
4404 <p>For example, the following configuration will process all files
4405 in the <code>/www/data/</code> directory for server-side
4408 <pre class="prettyprint lang-config"><Directory "/www/data/">
4409 SetOutputFilter INCLUDES
4410 </Directory></pre>
4413 <p>If more than one filter is specified, they must be separated
4414 by semicolons in the order in which they should process the
4419 <li><a href="../filter.html">Filters</a> documentation</li>
4422 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4423 <div class="directive-section"><h2><a name="TimeOut" id="TimeOut">TimeOut</a> <a name="timeout" id="timeout">Directive</a></h2>
4424 <table class="directive">
4425 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for
4426 certain events before failing a request</td></tr>
4427 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TimeOut <var>seconds</var></code></td></tr>
4428 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TimeOut 60</code></td></tr>
4429 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4430 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4431 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4433 <p>The <code class="directive">TimeOut</code> directive defines the length
4434 of time Apache httpd will wait for I/O in various circumstances:</p>
4437 <li>When reading data from the client, the length of time to
4438 wait for a TCP packet to arrive if the read buffer is
4441 <li>When writing data to the client, the length of time to wait
4442 for an acknowledgement of a packet if the send buffer is
4445 <li>In <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code> and <code class="module"><a href="../mod/mod_cgid.html">mod_cgid</a></code>,
4446 the length of time to wait for output from a CGI script.</li>
4448 <li>In <code class="module"><a href="../mod/mod_ext_filter.html">mod_ext_filter</a></code>, the length of time to
4449 wait for output from a filtering process.</li>
4451 <li>In <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>, the default timeout value if
4452 <code class="directive"><a href="../mod/mod_proxy.html#proxytimeout">ProxyTimeout</a></code> is not
4458 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4459 <div class="directive-section"><h2><a name="TraceEnable" id="TraceEnable">TraceEnable</a> <a name="traceenable" id="traceenable">Directive</a></h2>
4460 <table class="directive">
4461 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines the behavior on <code>TRACE</code> requests</td></tr>
4462 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TraceEnable <var>[on|off|extended]</var></code></td></tr>
4463 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TraceEnable on</code></td></tr>
4464 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4465 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4466 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4468 <p>This directive overrides the behavior of <code>TRACE</code> for both
4469 the core server and <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>. The default
4470 <code>TraceEnable on</code> permits <code>TRACE</code> requests per
4471 RFC 2616, which disallows any request body to accompany the request.
4472 <code>TraceEnable off</code> causes the core server and
4473 <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> to return a <code>405</code> (Method not
4474 allowed) error to the client.</p>
4476 <p>Finally, for testing and diagnostic purposes only, request
4477 bodies may be allowed using the non-compliant <code>TraceEnable
4478 extended</code> directive. The core (as an origin server) will
4479 restrict the request body to 64k (plus 8k for chunk headers if
4480 <code>Transfer-Encoding: chunked</code> is used). The core will
4481 reflect the full headers and all chunk headers with the response
4482 body. As a proxy server, the request body is not restricted to 64k.</p>
4484 <div class="note"><h3>Note</h3>
4485 <p>Despite claims to the contrary, <code>TRACE</code> is not
4486 a security vulnerability, and there is no viable reason for
4487 it to be disabled. Doing so necessarily makes your server
4492 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4493 <div class="directive-section"><h2><a name="UnDefine" id="UnDefine">UnDefine</a> <a name="undefine" id="undefine">Directive</a></h2>
4494 <table class="directive">
4495 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Undefine the existence of a variable</td></tr>
4496 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UnDefine <var>parameter-name</var></code></td></tr>
4497 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4498 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4499 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4501 <p>Undoes the effect of a <code class="directive"><a href="#define">Define</a></code> or
4502 of passing a <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</p>
4503 <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
4504 <code>-D</code> arguments in any startup scripts.</p>
4505 <p>While this directive is supported in virtual host context,
4506 the changes it makes are visible to any later configuration
4507 directives, beyond any enclosing virtual host.</p>
4510 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4511 <div class="directive-section"><h2><a name="UseCanonicalName" id="UseCanonicalName">UseCanonicalName</a> <a name="usecanonicalname" id="usecanonicalname">Directive</a></h2>
4512 <table class="directive">
4513 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own name and
4515 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalName On|Off|DNS</code></td></tr>
4516 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalName Off</code></td></tr>
4517 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4518 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4519 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4521 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4522 URL -- that is, a URL that refers back to the same server. With
4523 <code>UseCanonicalName On</code> Apache httpd will use the hostname and port
4524 specified in the <code class="directive"><a href="#servername">ServerName</a></code>
4525 directive to construct the canonical name for the server. This name
4526 is used in all self-referential URLs, and for the values of
4527 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>
4529 <p>With <code>UseCanonicalName Off</code> Apache httpd will form
4530 self-referential URLs using the hostname and port supplied by
4531 the client if any are supplied (otherwise it will use the
4532 canonical name, as defined above). These values are the same
4533 that are used to implement <a href="../vhosts/name-based.html">name-based virtual hosts</a>
4534 and are available with the same clients. The CGI variables
4535 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
4536 constructed from the client supplied values as well.</p>
4538 <p>An example where this may be useful is on an intranet server
4539 where you have users connecting to the machine using short
4540 names such as <code>www</code>. You'll notice that if the users
4541 type a shortname and a URL which is a directory, such as
4542 <code>http://www/splat</code>, <em>without the trailing
4543 slash</em>, then Apache httpd will redirect them to
4544 <code>http://www.example.com/splat/</code>. If you have
4545 authentication enabled, this will cause the user to have to
4546 authenticate twice (once for <code>www</code> and once again
4547 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">
4548 the FAQ on this subject for more information</a>). But if
4549 <code class="directive">UseCanonicalName</code> is set <code>Off</code>, then
4550 Apache httpd will redirect to <code>http://www/splat/</code>.</p>
4552 <p>There is a third option, <code>UseCanonicalName DNS</code>,
4553 which is intended for use with mass IP-based virtual hosting to
4554 support ancient clients that do not provide a
4555 <code>Host:</code> header. With this option, Apache httpd does a
4556 reverse DNS lookup on the server IP address that the client
4557 connected to in order to work out self-referential URLs.</p>
4559 <div class="warning"><h3>Warning</h3>
4560 <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>,
4561 they may be broken by this option. The client is essentially free
4562 to give whatever value they want as a hostname. But if the CGI is
4563 only using <code>SERVER_NAME</code> to construct self-referential URLs,
4564 then it should be just fine.</p>
4569 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
4570 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4571 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4574 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4575 <div class="directive-section"><h2><a name="UseCanonicalPhysicalPort" id="UseCanonicalPhysicalPort">UseCanonicalPhysicalPort</a> <a name="usecanonicalphysicalport" id="usecanonicalphysicalport">Directive</a></h2>
4576 <table class="directive">
4577 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own port</td></tr>
4578 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalPhysicalPort On|Off</code></td></tr>
4579 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalPhysicalPort Off</code></td></tr>
4580 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4581 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4582 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4584 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4585 URL -- that is, a URL that refers back to the same server. With
4586 <code>UseCanonicalPhysicalPort On</code>, Apache httpd will, when
4587 constructing the canonical port for the server to honor
4588 the <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> directive,
4589 provide the actual physical port number being used by this request
4590 as a potential port. With <code>UseCanonicalPhysicalPort Off</code>,
4591 Apache httpd will not ever use the actual physical port number, instead
4592 relying on all configured information to construct a valid port number.</p>
4594 <div class="note"><h3>Note</h3>
4595 <p>The ordering of the lookup when the physical port is used is as
4598 <dt><code>UseCanonicalName On</code></dt>
4601 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4602 <li>Physical port</li>
4603 <li>Default port</li>
4606 <dt><code>UseCanonicalName Off | DNS</code></dt>
4609 <li>Parsed port from <code>Host:</code> header</li>
4610 <li>Physical port</li>
4611 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4612 <li>Default port</li>
4617 <p>With <code>UseCanonicalPhysicalPort Off</code>, the
4618 physical ports are removed from the ordering.</p>
4624 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
4625 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4626 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4629 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4630 <div class="directive-section"><h2><a name="VirtualHost" id="VirtualHost"><VirtualHost></a> <a name="virtualhost" id="virtualhost">Directive</a></h2>
4631 <table class="directive">
4632 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only to a specific
4633 hostname or IP address</td></tr>
4634 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><VirtualHost
4635 <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
4636 ...> ... </VirtualHost></code></td></tr>
4637 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4638 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4639 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4641 <p><code class="directive"><VirtualHost></code> and
4642 <code></VirtualHost></code> are used to enclose a group of
4643 directives that will apply only to a particular virtual host. Any
4644 directive that is allowed in a virtual host context may be
4645 used. When the server receives a request for a document on a
4646 particular virtual host, it uses the configuration directives
4647 enclosed in the <code class="directive"><VirtualHost></code>
4648 section. <var>Addr</var> can be any of the following, optionally followed by
4649 a colon and a port number (or *):</p>
4652 <li>The IP address of the virtual host;</li>
4654 <li>A fully qualified domain name for the IP address of the
4655 virtual host (not recommended);</li>
4657 <li>The character <code>*</code>, which acts as a wildcard and matches
4658 any IP address.</li>
4660 <li>The string <code>_default_</code>, which is an alias for <code>*</code></li>
4664 <pre class="prettyprint lang-config"><VirtualHost 10.1.2.3:80>
4665 ServerAdmin webmaster@host.example.com
4666 DocumentRoot "/www/docs/host.example.com"
4667 ServerName host.example.com
4668 ErrorLog "logs/host.example.com-error_log"
4669 TransferLog "logs/host.example.com-access_log"
4670 </VirtualHost></pre>
4674 <p>IPv6 addresses must be specified in square brackets because
4675 the optional port number could not be determined otherwise. An
4676 IPv6 example is shown below:</p>
4678 <pre class="prettyprint lang-config"><VirtualHost [2001:db8::a00:20ff:fea7:ccea]:80>
4679 ServerAdmin webmaster@host.example.com
4680 DocumentRoot "/www/docs/host.example.com"
4681 ServerName host.example.com
4682 ErrorLog "logs/host.example.com-error_log"
4683 TransferLog "logs/host.example.com-access_log"
4684 </VirtualHost></pre>
4687 <p>Each Virtual Host must correspond to a different IP address,
4688 different port number, or a different host name for the server,
4689 in the former case the server machine must be configured to
4690 accept IP packets for multiple addresses. (If the machine does
4691 not have multiple network interfaces, then this can be
4692 accomplished with the <code>ifconfig alias</code> command -- if
4693 your OS supports it).</p>
4695 <div class="note"><h3>Note</h3>
4696 <p>The use of <code class="directive"><VirtualHost></code> does
4697 <strong>not</strong> affect what addresses Apache httpd listens on. You
4698 may need to ensure that Apache httpd is listening on the correct addresses
4699 using <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>.</p>
4702 <p>A <code class="directive"><a href="#servername">ServerName</a></code> should be
4703 specified inside each <code class="directive"><VirtualHost></code> block. If it is absent, the
4704 <code class="directive"><a href="#servername">ServerName</a></code> from the "main"
4705 server configuration will be inherited.</p>
4707 <p>When a request is received, the server first maps it to the best matching
4708 <code class="directive"><VirtualHost></code> based on the local
4709 IP address and port combination only. Non-wildcards have a higher
4710 precedence. If no match based on IP and port occurs at all, the
4711 "main" server configuration is used.</p>
4713 <p>If multiple virtual hosts contain the best matching IP address and port,
4714 the server selects from these virtual hosts the best match based on the
4715 requested hostname. If no matching name-based virtual host is found,
4716 then the first listed virtual host that matched the IP address will be
4717 used. As a consequence, the first listed virtual host for a given IP address
4718 and port combination is the default virtual host for that IP and port
4721 <div class="warning"><h3>Security</h3>
4722 <p>See the <a href="../misc/security_tips.html">security tips</a>
4723 document for details on why your security could be compromised if the
4724 directory where log files are stored is writable by anyone other
4725 than the user that starts the server.</p>
4730 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4731 <li><a href="../dns-caveats.html">Issues Regarding DNS and
4732 Apache HTTP Server</a></li>
4733 <li><a href="../bind.html">Setting
4734 which addresses and ports Apache HTTP Server uses</a></li>
4735 <li><a href="../sections.html">How <Directory>, <Location>
4736 and <Files> sections work</a> for an explanation of how these
4737 different sections are combined when a request is received</li>
4740 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4741 <div class="directive-section"><h2><a name="Warning" id="Warning">Warning</a> <a name="warning" id="warning">Directive</a></h2>
4742 <table class="directive">
4743 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Warn from configuration parsing with a custom message</td></tr>
4744 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Warning <var>message</var></code></td></tr>
4745 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4746 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4747 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4748 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.5 and later</td></tr>
4750 <p>If an issue can be detected from within the configuration, this
4751 directive can be used to generate a custom warning message. The
4752 configuration parsing is not halted. The typical use is to check
4753 whether some user define options are set, and warn if not.</p>
4755 <pre class="prettyprint lang-config"># Example
4756 # tell when ReverseProxy is not set
4757 <IfDefine !ReverseProxy>
4758 Warning "reverse proxy is not started, hope this is okay!"
4761 <IfDefine ReverseProxy>
4762 # define custom proxy configuration
4763 </IfDefine></pre>
4769 <div class="bottomlang">
4770 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
4771 <a href="../en/mod/core.html" title="English"> en </a> |
4772 <a href="../es/mod/core.html" hreflang="es" rel="alternate" title="Español"> es </a> |
4773 <a href="../fr/mod/core.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
4774 <a href="../ja/mod/core.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
4775 <a href="../tr/mod/core.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p>
4776 </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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