1 <?xml version="1.0" encoding="ISO-8859-1"?>
2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
3 <html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><!--
4 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
5 This file is generated from xml source: DO NOT EDIT
6 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
8 <title>core - Apache HTTP Server Version 2.4</title>
9 <link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" />
10 <link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" />
11 <link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /><link rel="stylesheet" type="text/css" href="../style/css/prettify.css" />
12 <script src="../style/scripts/prettify.min.js" type="text/javascript">
15 <link href="../images/favicon.ico" rel="shortcut icon" /></head>
17 <div id="page-header">
18 <p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p>
19 <p class="apache">Apache HTTP Server Version 2.4</p>
20 <img alt="" src="../images/feather.gif" /></div>
21 <div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div>
23 <a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.4</a> > <a href="./">Modules</a></div>
24 <div id="page-content">
25 <div id="preamble"><h1>Apache Core Features</h1>
27 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
28 <a href="../en/mod/core.html" title="English"> en </a> |
29 <a href="../es/mod/core.html" hreflang="es" rel="alternate" title="Español"> es </a> |
30 <a href="../fr/mod/core.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
31 <a href="../ja/mod/core.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
32 <a href="../tr/mod/core.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p>
34 <table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Core Apache HTTP Server features that are always
36 <tr><th><a href="module-dict.html#Status">Status:</a></th><td>Core</td></tr></table>
38 <div id="quickview"><h3 class="directives">Directives</h3>
40 <li><img alt="" src="../images/down.gif" /> <a href="#acceptfilter">AcceptFilter</a></li>
41 <li><img alt="" src="../images/down.gif" /> <a href="#acceptpathinfo">AcceptPathInfo</a></li>
42 <li><img alt="" src="../images/down.gif" /> <a href="#accessfilename">AccessFileName</a></li>
43 <li><img alt="" src="../images/down.gif" /> <a href="#adddefaultcharset">AddDefaultCharset</a></li>
44 <li><img alt="" src="../images/down.gif" /> <a href="#allowencodedslashes">AllowEncodedSlashes</a></li>
45 <li><img alt="" src="../images/down.gif" /> <a href="#allowoverride">AllowOverride</a></li>
46 <li><img alt="" src="../images/down.gif" /> <a href="#allowoverridelist">AllowOverrideList</a></li>
47 <li><img alt="" src="../images/down.gif" /> <a href="#cgimapextension">CGIMapExtension</a></li>
48 <li><img alt="" src="../images/down.gif" /> <a href="#contentdigest">ContentDigest</a></li>
49 <li><img alt="" src="../images/down.gif" /> <a href="#defaultruntimedir">DefaultRuntimeDir</a></li>
50 <li><img alt="" src="../images/down.gif" /> <a href="#defaulttype">DefaultType</a></li>
51 <li><img alt="" src="../images/down.gif" /> <a href="#define">Define</a></li>
52 <li><img alt="" src="../images/down.gif" /> <a href="#directory"><Directory></a></li>
53 <li><img alt="" src="../images/down.gif" /> <a href="#directorymatch"><DirectoryMatch></a></li>
54 <li><img alt="" src="../images/down.gif" /> <a href="#documentroot">DocumentRoot</a></li>
55 <li><img alt="" src="../images/down.gif" /> <a href="#else"><Else></a></li>
56 <li><img alt="" src="../images/down.gif" /> <a href="#elseif"><ElseIf></a></li>
57 <li><img alt="" src="../images/down.gif" /> <a href="#enablemmap">EnableMMAP</a></li>
58 <li><img alt="" src="../images/down.gif" /> <a href="#enablesendfile">EnableSendfile</a></li>
59 <li><img alt="" src="../images/down.gif" /> <a href="#error">Error</a></li>
60 <li><img alt="" src="../images/down.gif" /> <a href="#errordocument">ErrorDocument</a></li>
61 <li><img alt="" src="../images/down.gif" /> <a href="#errorlog">ErrorLog</a></li>
62 <li><img alt="" src="../images/down.gif" /> <a href="#errorlogformat">ErrorLogFormat</a></li>
63 <li><img alt="" src="../images/down.gif" /> <a href="#extendedstatus">ExtendedStatus</a></li>
64 <li><img alt="" src="../images/down.gif" /> <a href="#fileetag">FileETag</a></li>
65 <li><img alt="" src="../images/down.gif" /> <a href="#files"><Files></a></li>
66 <li><img alt="" src="../images/down.gif" /> <a href="#filesmatch"><FilesMatch></a></li>
67 <li><img alt="" src="../images/down.gif" /> <a href="#forcetype">ForceType</a></li>
68 <li><img alt="" src="../images/down.gif" /> <a href="#gprofdir">GprofDir</a></li>
69 <li><img alt="" src="../images/down.gif" /> <a href="#hostnamelookups">HostnameLookups</a></li>
70 <li><img alt="" src="../images/down.gif" /> <a href="#if"><If></a></li>
71 <li><img alt="" src="../images/down.gif" /> <a href="#ifdefine"><IfDefine></a></li>
72 <li><img alt="" src="../images/down.gif" /> <a href="#ifmodule"><IfModule></a></li>
73 <li><img alt="" src="../images/down.gif" /> <a href="#include">Include</a></li>
74 <li><img alt="" src="../images/down.gif" /> <a href="#includeoptional">IncludeOptional</a></li>
75 <li><img alt="" src="../images/down.gif" /> <a href="#keepalive">KeepAlive</a></li>
76 <li><img alt="" src="../images/down.gif" /> <a href="#keepalivetimeout">KeepAliveTimeout</a></li>
77 <li><img alt="" src="../images/down.gif" /> <a href="#limit"><Limit></a></li>
78 <li><img alt="" src="../images/down.gif" /> <a href="#limitexcept"><LimitExcept></a></li>
79 <li><img alt="" src="../images/down.gif" /> <a href="#limitinternalrecursion">LimitInternalRecursion</a></li>
80 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestbody">LimitRequestBody</a></li>
81 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfields">LimitRequestFields</a></li>
82 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfieldsize">LimitRequestFieldSize</a></li>
83 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestline">LimitRequestLine</a></li>
84 <li><img alt="" src="../images/down.gif" /> <a href="#limitxmlrequestbody">LimitXMLRequestBody</a></li>
85 <li><img alt="" src="../images/down.gif" /> <a href="#location"><Location></a></li>
86 <li><img alt="" src="../images/down.gif" /> <a href="#locationmatch"><LocationMatch></a></li>
87 <li><img alt="" src="../images/down.gif" /> <a href="#loglevel">LogLevel</a></li>
88 <li><img alt="" src="../images/down.gif" /> <a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></li>
89 <li><img alt="" src="../images/down.gif" /> <a href="#maxrangeoverlaps">MaxRangeOverlaps</a></li>
90 <li><img alt="" src="../images/down.gif" /> <a href="#maxrangereversals">MaxRangeReversals</a></li>
91 <li><img alt="" src="../images/down.gif" /> <a href="#maxranges">MaxRanges</a></li>
92 <li><img alt="" src="../images/down.gif" /> <a href="#mergetrailers">MergeTrailers</a></li>
93 <li><img alt="" src="../images/down.gif" /> <a href="#mutex">Mutex</a></li>
94 <li><img alt="" src="../images/down.gif" /> <a href="#namevirtualhost">NameVirtualHost</a></li>
95 <li><img alt="" src="../images/down.gif" /> <a href="#options">Options</a></li>
96 <li><img alt="" src="../images/down.gif" /> <a href="#protocol">Protocol</a></li>
97 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitcpu">RLimitCPU</a></li>
98 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitmem">RLimitMEM</a></li>
99 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitnproc">RLimitNPROC</a></li>
100 <li><img alt="" src="../images/down.gif" /> <a href="#scriptinterpretersource">ScriptInterpreterSource</a></li>
101 <li><img alt="" src="../images/down.gif" /> <a href="#seerequesttail">SeeRequestTail</a></li>
102 <li><img alt="" src="../images/down.gif" /> <a href="#serveradmin">ServerAdmin</a></li>
103 <li><img alt="" src="../images/down.gif" /> <a href="#serveralias">ServerAlias</a></li>
104 <li><img alt="" src="../images/down.gif" /> <a href="#servername">ServerName</a></li>
105 <li><img alt="" src="../images/down.gif" /> <a href="#serverpath">ServerPath</a></li>
106 <li><img alt="" src="../images/down.gif" /> <a href="#serverroot">ServerRoot</a></li>
107 <li><img alt="" src="../images/down.gif" /> <a href="#serversignature">ServerSignature</a></li>
108 <li><img alt="" src="../images/down.gif" /> <a href="#servertokens">ServerTokens</a></li>
109 <li><img alt="" src="../images/down.gif" /> <a href="#sethandler">SetHandler</a></li>
110 <li><img alt="" src="../images/down.gif" /> <a href="#setinputfilter">SetInputFilter</a></li>
111 <li><img alt="" src="../images/down.gif" /> <a href="#setoutputfilter">SetOutputFilter</a></li>
112 <li><img alt="" src="../images/down.gif" /> <a href="#timeout">TimeOut</a></li>
113 <li><img alt="" src="../images/down.gif" /> <a href="#traceenable">TraceEnable</a></li>
114 <li><img alt="" src="../images/down.gif" /> <a href="#undefine">UnDefine</a></li>
115 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalname">UseCanonicalName</a></li>
116 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></li>
117 <li><img alt="" src="../images/down.gif" /> <a href="#virtualhost"><VirtualHost></a></li>
119 <ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div>
121 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
122 <div class="directive-section"><h2><a name="AcceptFilter" id="AcceptFilter">AcceptFilter</a> <a name="acceptfilter" id="acceptfilter">Directive</a></h2>
123 <table class="directive">
124 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures optimizations for a Protocol's Listener Sockets</td></tr>
125 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptFilter <var>protocol</var> <var>accept_filter</var></code></td></tr>
126 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
127 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
128 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
130 <p>This directive enables operating system specific optimizations for a
131 listening socket by the <code class="directive">Protocol</code> type.
132 The basic premise is for the kernel to not send a socket to the server
133 process until either data is received or an entire HTTP Request is buffered.
134 Only <a href="http://www.freebsd.org/cgi/man.cgi?query=accept_filter&sektion=9">
135 FreeBSD's Accept Filters</a>, Linux's more primitive
136 <code>TCP_DEFER_ACCEPT</code>, and Windows' optimized AcceptEx()
137 are currently supported.</p>
139 <p>Using <code>none</code> for an argument will disable any accept filters
140 for that protocol. This is useful for protocols that require a server
141 send data first, such as <code>ftp:</code> or <code>nntp</code>:</p>
142 <pre class="prettyprint lang-config">AcceptFilter nntp none</pre>
145 <p>The default protocol names are <code>https</code> for port 443
146 and <code>http</code> for all other ports. To specify another protocol
147 is being used with a listening port, add the <var>protocol</var>
148 argument to the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>
151 <p>The default values on FreeBSD are:</p>
152 <pre class="prettyprint lang-config">AcceptFilter http httpready
153 AcceptFilter https dataready</pre>
156 <p>The <code>httpready</code> accept filter buffers entire HTTP requests at
157 the kernel level. Once an entire request is received, the kernel then
158 sends it to the server. See the
159 <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_http&sektion=9">
160 accf_http(9)</a> man page for more details. Since HTTPS requests are
161 encrypted only the <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_data&sektion=9">
162 accf_data(9)</a> filter is used.</p>
164 <p>The default values on Linux are:</p>
165 <pre class="prettyprint lang-config">AcceptFilter http data
166 AcceptFilter https data</pre>
169 <p>Linux's <code>TCP_DEFER_ACCEPT</code> does not support buffering http
170 requests. Any value besides <code>none</code> will enable
171 <code>TCP_DEFER_ACCEPT</code> on that listener. For more details
173 <a href="http://homepages.cwi.nl/~aeb/linux/man2html/man7/tcp.7.html">
174 tcp(7)</a> man page.</p>
176 <p>The default values on Windows are:</p>
177 <pre class="prettyprint lang-config">AcceptFilter http data
178 AcceptFilter https data</pre>
181 <p>Window's mpm_winnt interprets the AcceptFilter to toggle the AcceptEx()
182 API, and does not support http protocol buffering. There are two values
183 which utilize the Windows AcceptEx() API and will recycle network
184 sockets between connections. <code>data</code> waits until data has
185 been transmitted as documented above, and the initial data buffer and
186 network endpoint addresses are all retrieved from the single AcceptEx()
187 invocation. <code>connect</code> will use the AcceptEx() API, also
188 retrieve the network endpoint addresses, but like <code>none</code>
189 the <code>connect</code> option does not wait for the initial data
192 <p>On Windows, <code>none</code> uses accept() rather than AcceptEx()
193 and will not recycle sockets between connections. This is useful for
194 network adapters with broken driver support, as well as some virtual
195 network providers such as vpn drivers, or spam, virus or spyware
201 <li><code class="directive"><a href="#protocol">Protocol</a></code></li>
204 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
205 <div class="directive-section"><h2><a name="AcceptPathInfo" id="AcceptPathInfo">AcceptPathInfo</a> <a name="acceptpathinfo" id="acceptpathinfo">Directive</a></h2>
206 <table class="directive">
207 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Resources accept trailing pathname information</td></tr>
208 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptPathInfo On|Off|Default</code></td></tr>
209 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AcceptPathInfo Default</code></td></tr>
210 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
211 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
212 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
213 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
216 <p>This directive controls whether requests that contain trailing
217 pathname information that follows an actual filename (or
218 non-existent file in an existing directory) will be accepted or
219 rejected. The trailing pathname information can be made
220 available to scripts in the <code>PATH_INFO</code> environment
223 <p>For example, assume the location <code>/test/</code> points to
224 a directory that contains only the single file
225 <code>here.html</code>. Then requests for
226 <code>/test/here.html/more</code> and
227 <code>/test/nothere.html/more</code> both collect
228 <code>/more</code> as <code>PATH_INFO</code>.</p>
230 <p>The three possible arguments for the
231 <code class="directive">AcceptPathInfo</code> directive are:</p>
233 <dt><code>Off</code></dt><dd>A request will only be accepted if it
234 maps to a literal path that exists. Therefore a request with
235 trailing pathname information after the true filename such as
236 <code>/test/here.html/more</code> in the above example will return
237 a 404 NOT FOUND error.</dd>
239 <dt><code>On</code></dt><dd>A request will be accepted if a
240 leading path component maps to a file that exists. The above
241 example <code>/test/here.html/more</code> will be accepted if
242 <code>/test/here.html</code> maps to a valid file.</dd>
244 <dt><code>Default</code></dt><dd>The treatment of requests with
245 trailing pathname information is determined by the <a href="../handler.html">handler</a> responsible for the request.
246 The core handler for normal files defaults to rejecting
247 <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
248 <code>PATH_INFO</code> by default.</dd>
251 <p>The primary purpose of the <code>AcceptPathInfo</code>
252 directive is to allow you to override the handler's choice of
253 accepting or rejecting <code>PATH_INFO</code>. This override is required,
254 for example, when you use a <a href="../filter.html">filter</a>, such
255 as <a href="mod_include.html">INCLUDES</a>, to generate content
256 based on <code>PATH_INFO</code>. The core handler would usually reject
257 the request, so you can use the following configuration to enable
260 <pre class="prettyprint lang-config"><Files "mypaths.shtml">
262 SetOutputFilter INCLUDES
269 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
270 <div class="directive-section"><h2><a name="AccessFileName" id="AccessFileName">AccessFileName</a> <a name="accessfilename" id="accessfilename">Directive</a></h2>
271 <table class="directive">
272 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Name of the distributed configuration file</td></tr>
273 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AccessFileName <var>filename</var> [<var>filename</var>] ...</code></td></tr>
274 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AccessFileName .htaccess</code></td></tr>
275 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
276 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
277 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
279 <p>While processing a request the server looks for
280 the first existing configuration file from this list of names in
281 every directory of the path to the document, if distributed
282 configuration files are <a href="#allowoverride">enabled for that
283 directory</a>. For example:</p>
285 <pre class="prettyprint lang-config">AccessFileName .acl</pre>
288 <p>before returning the document
289 <code>/usr/local/web/index.html</code>, the server will read
290 <code>/.acl</code>, <code>/usr/.acl</code>,
291 <code>/usr/local/.acl</code> and <code>/usr/local/web/.acl</code>
292 for directives, unless they have been disabled with</p>
294 <pre class="prettyprint lang-config"><Directory />
296 </Directory></pre>
301 <li><code class="directive"><a href="#allowoverride">AllowOverride</a></code></li>
302 <li><a href="../configuring.html">Configuration Files</a></li>
303 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
306 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
307 <div class="directive-section"><h2><a name="AddDefaultCharset" id="AddDefaultCharset">AddDefaultCharset</a> <a name="adddefaultcharset" id="adddefaultcharset">Directive</a></h2>
308 <table class="directive">
309 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Default charset parameter to be added when a response
310 content-type is <code>text/plain</code> or <code>text/html</code></td></tr>
311 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AddDefaultCharset On|Off|<var>charset</var></code></td></tr>
312 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AddDefaultCharset Off</code></td></tr>
313 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
314 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
315 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
316 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
318 <p>This directive specifies a default value for the media type
319 charset parameter (the name of a character encoding) to be added
320 to a response if and only if the response's content-type is either
321 <code>text/plain</code> or <code>text/html</code>. This should override
322 any charset specified in the body of the response via a <code>META</code>
323 element, though the exact behavior is often dependent on the user's client
324 configuration. A setting of <code>AddDefaultCharset Off</code>
325 disables this functionality. <code>AddDefaultCharset On</code> enables
326 a default charset of <code>iso-8859-1</code>. Any other value is assumed
327 to be the <var>charset</var> to be used, which should be one of the
328 <a href="http://www.iana.org/assignments/character-sets">IANA registered
329 charset values</a> for use in Internet media types (MIME types).
332 <pre class="prettyprint lang-config">AddDefaultCharset utf-8</pre>
335 <p><code class="directive">AddDefaultCharset</code> should only be used when all
336 of the text resources to which it applies are known to be in that
337 character encoding and it is too inconvenient to label their charset
338 individually. One such example is to add the charset parameter
339 to resources containing generated content, such as legacy CGI
340 scripts, that might be vulnerable to cross-site scripting attacks
341 due to user-provided data being included in the output. Note, however,
342 that a better solution is to just fix (or delete) those scripts, since
343 setting a default charset does not protect users that have enabled
344 the "auto-detect character encoding" feature on their browser.</p>
348 <li><code class="directive"><a href="../mod/mod_mime.html#addcharset">AddCharset</a></code></li>
351 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
352 <div class="directive-section"><h2><a name="AllowEncodedSlashes" id="AllowEncodedSlashes">AllowEncodedSlashes</a> <a name="allowencodedslashes" id="allowencodedslashes">Directive</a></h2>
353 <table class="directive">
354 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines whether encoded path separators in URLs are allowed to
355 be passed through</td></tr>
356 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowEncodedSlashes On|Off|NoDecode</code></td></tr>
357 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowEncodedSlashes Off</code></td></tr>
358 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
359 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
360 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
361 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>
362 NoDecode option available in 2.3.12 and later.</td></tr>
364 <p>The <code class="directive">AllowEncodedSlashes</code> directive allows URLs
365 which contain encoded path separators (<code>%2F</code> for <code>/</code>
366 and additionally <code>%5C</code> for <code>\</code> on according systems)
367 to be used in the path info.</p>
369 <p>With the default value, <code>Off</code>, such URLs are refused
370 with a 404 (Not found) error.</p>
372 <p>With the value <code>On</code>, such URLs are accepted, and encoded
373 slashes are decoded like all other encoded characters.</p>
375 <p>With the value <code>NoDecode</code>, such URLs are accepted, but
376 encoded slashes are not decoded but left in their encoded state.</p>
378 <p>Turning <code class="directive">AllowEncodedSlashes</code> <code>On</code> is
379 mostly useful when used in conjunction with <code>PATH_INFO</code>.</p>
381 <div class="note"><h3>Note</h3>
382 <p>If encoded slashes are needed in path info, use of <code>NoDecode</code> is
383 strongly recommended as a security measure. Allowing slashes
384 to be decoded could potentially allow unsafe paths.</p>
389 <li><code class="directive"><a href="#acceptpathinfo">AcceptPathInfo</a></code></li>
392 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
393 <div class="directive-section"><h2><a name="AllowOverride" id="AllowOverride">AllowOverride</a> <a name="allowoverride" id="allowoverride">Directive</a></h2>
394 <table class="directive">
395 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Types of directives that are allowed in
396 <code>.htaccess</code> files</td></tr>
397 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowOverride All|None|<var>directive-type</var>
398 [<var>directive-type</var>] ...</code></td></tr>
399 <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>
400 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
401 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
402 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
404 <p>When the server finds an <code>.htaccess</code> file (as
405 specified by <code class="directive"><a href="#accessfilename">AccessFileName</a></code>)
406 it needs to know which directives declared in that file can override
407 earlier configuration directives.</p>
409 <div class="note"><h3>Only available in <Directory> sections</h3>
410 <code class="directive">AllowOverride</code> is valid only in
411 <code class="directive"><a href="#directory"><Directory></a></code>
412 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
413 <code class="directive"><a href="#files"><Files></a></code> sections.
416 <p>When this directive is set to <code>None</code> and <code class="directive"><a href="#allowoverridelist">AllowOverrideList</a></code> is set to
417 <code>None</code> <a href="#accessfilename">.htaccess</a> files are
418 completely ignored. In this case, the server will not even attempt
419 to read <code>.htaccess</code> files in the filesystem.</p>
421 <p>When this directive is set to <code>All</code>, then any
422 directive which has the .htaccess <a href="directive-dict.html#Context">Context</a> is allowed in
423 <code>.htaccess</code> files.</p>
425 <p>The <var>directive-type</var> can be one of the following
426 groupings of directives.</p>
433 Allow use of the authorization directives (<code class="directive"><a href="../mod/mod_authz_dbm.html#authdbmgroupfile">AuthDBMGroupFile</a></code>,
434 <code class="directive"><a href="../mod/mod_authn_dbm.html#authdbmuserfile">AuthDBMUserFile</a></code>,
435 <code class="directive"><a href="../mod/mod_authz_groupfile.html#authgroupfile">AuthGroupFile</a></code>,
436 <code class="directive"><a href="../mod/mod_authn_core.html#authname">AuthName</a></code>,
437 <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>
442 Allow use of the directives controlling document types
443 (<code class="directive"><a href="#errordocument">ErrorDocument</a></code>,
444 <code class="directive"><a href="#forcetype">ForceType</a></code>,
445 <code class="directive"><a href="../mod/mod_negotiation.html#languagepriority">LanguagePriority</a></code>,
446 <code class="directive"><a href="#sethandler">SetHandler</a></code>,
447 <code class="directive"><a href="#setinputfilter">SetInputFilter</a></code>,
448 <code class="directive"><a href="#setoutputfilter">SetOutputFilter</a></code>, and
449 <code class="module"><a href="../mod/mod_mime.html">mod_mime</a></code> Add* and Remove* directives),
450 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>),
451 <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>),
452 <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
453 <code class="directive"><a href="../mod/mod_actions.html#action">Action</a></code> from
454 <code class="module"><a href="../mod/mod_actions.html">mod_actions</a></code>.
460 Allow use of the directives controlling directory indexing
461 (<code class="directive"><a href="../mod/mod_autoindex.html#adddescription">AddDescription</a></code>,
462 <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>,
463 <code class="directive"><a href="../mod/mod_autoindex.html#addiconbytype">AddIconByType</a></code>,
464 <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>, <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>,
470 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>
472 <dt>Nonfatal=[Override|Unknown|All]</dt>
475 Allow use of AllowOverride option to treat syntax errors in
476 .htaccess as non-fatal: instead of causing an Internal Server
477 Error, disallowed or unrecognised directives will be ignored
478 and a warning logged:
480 <li><strong>Nonfatal=Override</strong> treats directives
481 forbidden by AllowOverride as non-fatal.</li>
482 <li><strong>Nonfatal=Unknown</strong> treats unknown directives
483 as non-fatal. This covers typos and directives implemented
484 by a module that's not present.</li>
485 <li><strong>Nonfatal=All</strong> treats both the above as non-fatal.</li>
487 <p>Note that a syntax error in a valid directive will still cause
488 an internal server error.</p>
489 <div class="warning"><h3>Security</h3>
490 Nonfatal errors may have security implications for .htaccess users.
491 For example, if AllowOverride disallows AuthConfig, users'
492 configuration designed to restrict access to a site will be disabled.
496 <dt>Options[=<var>Option</var>,...]</dt>
499 Allow use of the directives controlling specific directory
500 features (<code class="directive"><a href="#options">Options</a></code> and
501 <code class="directive"><a href="../mod/mod_include.html#xbithack">XBitHack</a></code>).
502 An equal sign may be given followed by a comma (but no spaces)
503 separated lists of options that may be set using the <code class="directive"><a href="#options">Options</a></code> command.
505 <div class="note"><h3>Implicit disabling of Options</h3>
506 <p>Even though the list of options that may be used in .htaccess files
507 can be limited with this directive, as long as any <code class="directive"><a href="#options">Options</a></code> directive is allowed any
508 other inherited option can be disabled by using the non-relative
509 syntax. In other words, this mechanism cannot force a specific option
510 to remain <em>set</em> while allowing any others to be set.
513 <div class="example"><p><code>
514 AllowOverride Options=Indexes,MultiViews
521 <pre class="prettyprint lang-config">AllowOverride AuthConfig Indexes</pre>
524 <p>In the example above all directives that are neither in the group
525 <code>AuthConfig</code> nor <code>Indexes</code> cause an internal
528 <div class="note"><p>For security and performance reasons, do not set
529 <code>AllowOverride</code> to anything other than <code>None</code>
530 in your <code><Directory /></code> block. Instead, find (or
531 create) the <code><Directory></code> block that refers to the
532 directory where you're actually planning to place a
533 <code>.htaccess</code> file.</p>
538 <li><code class="directive"><a href="#accessfilename">AccessFileName</a></code></li>
539 <li><code class="directive"><a href="#allowoverridelist">AllowOverrideList</a></code></li>
540 <li><a href="../configuring.html">Configuration Files</a></li>
541 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
544 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
545 <div class="directive-section"><h2><a name="AllowOverrideList" id="AllowOverrideList">AllowOverrideList</a> <a name="allowoverridelist" id="allowoverridelist">Directive</a></h2>
546 <table class="directive">
547 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Individual directives that are allowed in
548 <code>.htaccess</code> files</td></tr>
549 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowOverrideList None|<var>directive</var>
550 [<var>directive-type</var>] ...</code></td></tr>
551 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowOverrideList None</code></td></tr>
552 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
553 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
554 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
556 <p>When the server finds an <code>.htaccess</code> file (as
557 specified by <code class="directive"><a href="#accessfilename">AccessFileName</a></code>)
558 it needs to know which directives declared in that file can override
559 earlier configuration directives.</p>
561 <div class="note"><h3>Only available in <Directory> sections</h3>
562 <code class="directive">AllowOverrideList</code> is valid only in
563 <code class="directive"><a href="#directory"><Directory></a></code>
564 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
565 <code class="directive"><a href="#files"><Files></a></code> sections.
568 <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>,
569 then <a href="#accessfilename">.htaccess</a> files are completely
570 ignored. In this case, the server will not even attempt to read
571 <code>.htaccess</code> files in the filesystem.</p>
575 <pre class="prettyprint lang-config">AllowOverride None
576 AllowOverrideList Redirect RedirectMatch</pre>
579 <p>In the example above only the <code>Redirect</code> and
580 <code>RedirectMatch</code> directives are allowed. All others will
581 cause an internal server error.</p>
585 <pre class="prettyprint lang-config">AllowOverride AuthConfig
586 AllowOverrideList CookieTracking CookieName</pre>
589 <p>In the example above <code class="directive"><a href="#allowoverride">AllowOverride
590 </a></code> grants permission to the <code>AuthConfig</code>
591 directive grouping and <code class="directive">AllowOverrideList</code> grants
592 permission to only two directives from the <code>FileInfo</code> directive
593 grouping. All others will cause an internal server error.</p>
597 <li><code class="directive"><a href="#accessfilename">AccessFileName</a></code></li>
598 <li><code class="directive"><a href="#allowoverride">AllowOverride</a></code></li>
599 <li><a href="../configuring.html">Configuration Files</a></li>
600 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
603 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
604 <div class="directive-section"><h2><a name="CGIMapExtension" id="CGIMapExtension">CGIMapExtension</a> <a name="cgimapextension" id="cgimapextension">Directive</a></h2>
605 <table class="directive">
606 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
608 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CGIMapExtension <var>cgi-path</var> <var>.extension</var></code></td></tr>
609 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
610 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
611 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
612 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
613 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>NetWare only</td></tr>
615 <p>This directive is used to control how Apache httpd finds the
616 interpreter used to run CGI scripts. For example, setting
617 <code>CGIMapExtension sys:\foo.nlm .foo</code> will
618 cause all CGI script files with a <code>.foo</code> extension to
619 be passed to the FOO interpreter.</p>
622 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
623 <div class="directive-section"><h2><a name="ContentDigest" id="ContentDigest">ContentDigest</a> <a name="contentdigest" id="contentdigest">Directive</a></h2>
624 <table class="directive">
625 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables the generation of <code>Content-MD5</code> HTTP Response
627 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ContentDigest On|Off</code></td></tr>
628 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ContentDigest Off</code></td></tr>
629 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
630 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
631 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
632 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
634 <p>This directive enables the generation of
635 <code>Content-MD5</code> headers as defined in RFC1864
636 respectively RFC2616.</p>
638 <p>MD5 is an algorithm for computing a "message digest"
639 (sometimes called "fingerprint") of arbitrary-length data, with
640 a high degree of confidence that any alterations in the data
641 will be reflected in alterations in the message digest.</p>
643 <p>The <code>Content-MD5</code> header provides an end-to-end
644 message integrity check (MIC) of the entity-body. A proxy or
645 client may check this header for detecting accidental
646 modification of the entity-body in transit. Example header:</p>
648 <div class="example"><p><code>
649 Content-MD5: AuLb7Dp1rqtRtxz2m9kRpA==
652 <p>Note that this can cause performance problems on your server
653 since the message digest is computed on every request (the
654 values are not cached).</p>
656 <p><code>Content-MD5</code> is only sent for documents served
657 by the <code class="module"><a href="../mod/core.html">core</a></code>, and not by any module. For example,
658 SSI documents, output from CGI scripts, and byte range responses
659 do not have this header.</p>
662 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
663 <div class="directive-section"><h2><a name="DefaultRuntimeDir" id="DefaultRuntimeDir">DefaultRuntimeDir</a> <a name="defaultruntimedir" id="defaultruntimedir">Directive</a></h2>
664 <table class="directive">
665 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server run-time files</td></tr>
666 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultRuntimeDir <var>directory-path</var></code></td></tr>
667 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultRuntimeDir DEFAULT_REL_RUNTIMEDIR (logs/)</code></td></tr>
668 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
669 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
670 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
671 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.4.2 and later</td></tr>
673 <p>The <code class="directive">DefaultRuntimeDir</code> directive sets the
674 directory in which the server will create various run-time files
675 (shared memory, locks, etc.). If set as a relative path, the full path
676 will be relative to <code class="directive">ServerRoot</code>.</p>
678 <p><strong>Example</strong></p>
679 <pre class="prettyprint lang-config">DefaultRuntimeDir scratch/</pre>
682 <p>The default location of <code class="directive">DefaultRuntimeDir</code> may be
683 modified by changing the <code>DEFAULT_REL_RUNTIMEDIR</code> #define
686 <p>Note: <code class="directive">ServerRoot</code> should be specified before this
687 directive is used, otherwise the default value of <code class="directive">ServerRoot</code>
688 would be used to set the base directory.</p>
693 <li><a href="../misc/security_tips.html#serverroot">the
694 security tips</a> for information on how to properly set
695 permissions on the <code class="directive">ServerRoot</code></li>
698 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
699 <div class="directive-section"><h2><a name="DefaultType" id="DefaultType">DefaultType</a> <a name="defaulttype" id="defaulttype">Directive</a></h2>
700 <table class="directive">
701 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>This directive has no effect other than to emit warnings
702 if the value is not <code>none</code>. In prior versions, DefaultType
703 would specify a default media type to assign to response content for
704 which no other media type configuration could be found.
706 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultType <var>media-type|none</var></code></td></tr>
707 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultType none</code></td></tr>
708 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
709 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
710 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
711 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
712 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>The argument <code>none</code> is available in Apache httpd 2.2.7 and later. All other choices are DISABLED for 2.3.x and later.</td></tr>
714 <p>This directive has been disabled. For backwards compatibility
715 of configuration files, it may be specified with the value
716 <code>none</code>, meaning no default media type. For example:</p>
718 <pre class="prettyprint lang-config">DefaultType None</pre>
721 <p><code>DefaultType None</code> is only available in
722 httpd-2.2.7 and later.</p>
724 <p>Use the mime.types configuration file and the
725 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code> to configure media
726 type assignments via file extensions, or the
727 <code class="directive"><a href="#forcetype">ForceType</a></code> directive to configure
728 the media type for specific resources. Otherwise, the server will
729 send the response without a Content-Type header field and the
730 recipient may attempt to guess the media type.</p>
733 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
734 <div class="directive-section"><h2><a name="Define" id="Define">Define</a> <a name="define" id="define">Directive</a></h2>
735 <table class="directive">
736 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Define a variable</td></tr>
737 <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>
738 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</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>
742 <p>In its one parameter form, <code class="directive">Define</code> is equivalent
743 to passing the <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>. It
744 can be used to toggle the use of
745 <code class="directive"><a href="#ifdefine"><IfDefine></a></code> sections
746 without needing to alter <code>-D</code> arguments in any startup
749 <p>In addition to that, if the second parameter is given, a config variable
750 is set to this value. The variable can be used in the configuration using
751 the <code>${VAR}</code> syntax. The variable is always globally defined
752 and not limited to the scope of the surrounding config section.</p>
754 <pre class="prettyprint lang-config"><IfDefine TEST>
755 Define servername test.example.com
757 <IfDefine !TEST>
758 Define servername www.example.com
762 DocumentRoot /var/www/${servername}/htdocs</pre>
765 <p>Variable names may not contain colon ":" characters, to avoid clashes
766 with <code class="directive"><a href="../mod/mod_rewrite.html#rewritemap">RewriteMap</a></code>'s syntax.</p>
769 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
770 <div class="directive-section"><h2><a name="Directory" id="Directory"><Directory></a> <a name="directory" id="directory">Directive</a></h2>
771 <table class="directive">
772 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose a group of directives that apply only to the
773 named file-system directory, sub-directories, and their contents.</td></tr>
774 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Directory <var>directory-path</var>>
775 ... </Directory></code></td></tr>
776 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
777 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
778 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
780 <p><code class="directive"><Directory></code> and
781 <code></Directory></code> are used to enclose a group of
782 directives that will apply only to the named directory,
783 sub-directories of that directory, and the files within the respective
784 directories. Any directive that is allowed
785 in a directory context may be used. <var>Directory-path</var> is
786 either the full path to a directory, or a wild-card string using
787 Unix shell-style matching. In a wild-card string, <code>?</code> matches
788 any single character, and <code>*</code> matches any sequences of
789 characters. You may also use <code>[]</code> character ranges. None
790 of the wildcards match a `/' character, so <code><Directory
791 /*/public_html></code> will not match
792 <code>/home/user/public_html</code>, but <code><Directory
793 /home/*/public_html></code> will match. Example:</p>
795 <pre class="prettyprint lang-config"><Directory "/usr/local/httpd/htdocs">
796 Options Indexes FollowSymLinks
797 </Directory></pre>
801 <p>Be careful with the <var>directory-path</var> arguments:
802 They have to literally match the filesystem path which Apache httpd uses
803 to access the files. Directives applied to a particular
804 <code><Directory></code> will not apply to files accessed from
805 that same directory via a different path, such as via different symbolic
809 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular
810 expressions</a> can also be used, with the addition of the
811 <code>~</code> character. For example:</p>
813 <pre class="prettyprint lang-config"><Directory ~ "^/www/[0-9]{3}">
815 </Directory></pre>
818 <p>would match directories in <code>/www/</code> that consisted of
821 <p>If multiple (non-regular expression) <code class="directive"><Directory></code> sections
822 match the directory (or one of its parents) containing a document,
823 then the directives are applied in the order of shortest match
824 first, interspersed with the directives from the <a href="#accessfilename">.htaccess</a> files. For example,
827 <pre class="prettyprint lang-config"><Directory />
831 <Directory "/home">
832 AllowOverride FileInfo
833 </Directory></pre>
836 <p>for access to the document <code>/home/web/dir/doc.html</code>
840 <li>Apply directive <code>AllowOverride None</code>
841 (disabling <code>.htaccess</code> files).</li>
843 <li>Apply directive <code>AllowOverride FileInfo</code> (for
844 directory <code>/home</code>).</li>
846 <li>Apply any <code>FileInfo</code> directives in
847 <code>/home/.htaccess</code>, <code>/home/web/.htaccess</code> and
848 <code>/home/web/dir/.htaccess</code> in that order.</li>
851 <p>Regular expressions are not considered until after all of the
852 normal sections have been applied. Then all of the regular
853 expressions are tested in the order they appeared in the
854 configuration file. For example, with</p>
856 <pre class="prettyprint lang-config"><Directory ~ "abc$">
857 # ... directives here ...
858 </Directory></pre>
861 <p>the regular expression section won't be considered until after
862 all normal <code class="directive"><Directory></code>s and
863 <code>.htaccess</code> files have been applied. Then the regular
864 expression will match on <code>/home/abc/public_html/abc</code> and
865 the corresponding <code class="directive"><Directory></code> will
868 <p><strong>Note that the default access for
869 <code><Directory /></code> is to permit all access.
870 This means that Apache httpd will serve any file mapped from an URL. It is
871 recommended that you change this with a block such
874 <pre class="prettyprint lang-config"><Directory />
876 </Directory></pre>
879 <p><strong>and then override this for directories you
880 <em>want</em> accessible. See the <a href="../misc/security_tips.html">Security Tips</a> page for more
881 details.</strong></p>
883 <p>The directory sections occur in the <code>httpd.conf</code> file.
884 <code class="directive"><Directory></code> directives
885 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>
889 <li><a href="../sections.html">How <Directory>,
890 <Location> and <Files> sections work</a> for an
891 explanation of how these different sections are combined when a
892 request is received</li>
895 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
896 <div class="directive-section"><h2><a name="DirectoryMatch" id="DirectoryMatch"><DirectoryMatch></a> <a name="directorymatch" id="directorymatch">Directive</a></h2>
897 <table class="directive">
898 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose directives that apply to
899 the contents of file-system directories matching a regular expression.</td></tr>
900 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><DirectoryMatch <var>regex</var>>
901 ... </DirectoryMatch></code></td></tr>
902 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
903 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
904 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
906 <p><code class="directive"><DirectoryMatch></code> and
907 <code></DirectoryMatch></code> are used to enclose a group
908 of directives which will apply only to the named directory (and the files within),
909 the same as <code class="directive"><a href="#directory"><Directory></a></code>.
910 However, it takes as an argument a
911 <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>. For example:</p>
913 <pre class="prettyprint lang-config"><DirectoryMatch "^/www/(.+/)?[0-9]{3}">
915 </DirectoryMatch></pre>
918 <p>would match directories in <code>/www/</code> that consisted of three
921 <div class="note"><h3>Compatability</h3>
922 Prior to 2.3.9, this directive implicitly applied to sub-directories
923 (like <code class="directive"><a href="#directory"><Directory></a></code>) and
924 could not match the end of line symbol ($). In 2.3.9 and later,
925 only directories that match the expression are affected by the enclosed
929 <div class="note"><h3>Trailing Slash</h3>
930 This directive applies to requests for directories that may or may
931 not end in a trailing slash, so expressions that are anchored to the
932 end of line ($) must be written with care.
935 <p>From 2.4.8 onwards, named groups and backreferences are captured and
936 written to the environment with the corresponding name prefixed with
937 "MATCH_" and in upper case. This allows elements of paths to be referenced
938 from within <a href="../expr.html">expressions</a> and modules like
939 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
940 (unnamed) backreferences are ignored. Use named groups instead.</p>
942 <pre class="prettyprint lang-config"><DirectoryMatch ^/var/www/combined/(?<sitename>[^/]+)>
943 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
944 </DirectoryMatch></pre>
949 <li><code class="directive"><a href="#directory"><Directory></a></code> for
950 a description of how regular expressions are mixed in with normal
951 <code class="directive"><Directory></code>s</li>
952 <li><a href="../sections.html">How <Directory>, <Location> and
953 <Files> sections work</a> for an explanation of how these different
954 sections are combined when a request is received</li>
957 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
958 <div class="directive-section"><h2><a name="DocumentRoot" id="DocumentRoot">DocumentRoot</a> <a name="documentroot" id="documentroot">Directive</a></h2>
959 <table class="directive">
960 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory that forms the main document tree visible
961 from the web</td></tr>
962 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DocumentRoot <var>directory-path</var></code></td></tr>
963 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DocumentRoot /usr/local/apache/htdocs</code></td></tr>
964 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
965 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
966 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
968 <p>This directive sets the directory from which <code class="program"><a href="../programs/httpd.html">httpd</a></code>
969 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
970 path from the requested URL to the document root to make the
971 path to the document. Example:</p>
973 <pre class="prettyprint lang-config">DocumentRoot "/usr/web"</pre>
977 <code>http://my.example.com/index.html</code> refers to
978 <code>/usr/web/index.html</code>. If the <var>directory-path</var> is
979 not absolute then it is assumed to be relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
981 <p>The <code class="directive">DocumentRoot</code> should be specified without
982 a trailing slash.</p>
986 <li><a href="../urlmapping.html#documentroot">Mapping URLs to Filesystem
990 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
991 <div class="directive-section"><h2><a name="Else" id="Else"><Else></a> <a name="else" id="else">Directive</a></h2>
992 <table class="directive">
993 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if the condition of a
994 previous <code class="directive"><a href="#if"><If></a></code> or
995 <code class="directive"><a href="#elseif"><ElseIf></a></code> section is not
996 satisfied by a request at runtime</td></tr>
997 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Else> ... </Else></code></td></tr>
998 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
999 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1000 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1001 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1003 <p>The <code class="directive"><Else></code> applies the enclosed
1004 directives if and only if the most recent
1005 <code class="directive"><If></code> or
1006 <code class="directive"><ElseIf></code> section
1007 in the same scope has not been applied.
1008 For example: In </p>
1010 <pre class="prettyprint lang-config"><If "-z req('Host')">
1018 <p> The <code class="directive"><If></code> would match HTTP/1.0
1019 requests without a <var>Host:</var> header and the
1020 <code class="directive"><Else></code> would match requests
1021 with a <var>Host:</var> header.</p>
1026 <li><code class="directive"><a href="#if"><If></a></code></li>
1027 <li><code class="directive"><a href="#elseif"><ElseIf></a></code></li>
1028 <li><a href="../sections.html">How <Directory>, <Location>,
1029 <Files> sections work</a> for an explanation of how these
1030 different sections are combined when a request is received.
1031 <code class="directive"><If></code>,
1032 <code class="directive"><ElseIf></code>, and
1033 <code class="directive"><Else></code> are applied last.</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="ElseIf" id="ElseIf"><ElseIf></a> <a name="elseif" id="elseif">Directive</a></h2>
1038 <table class="directive">
1039 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is satisfied
1040 by a request at runtime while the condition of a previous
1041 <code class="directive"><a href="#if"><If></a></code> or
1042 <code class="directive"><ElseIf></code> section is not
1044 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><ElseIf <var>expression</var>> ... </ElseIf></code></td></tr>
1045 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1046 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1047 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1048 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1050 <p>The <code class="directive"><ElseIf></code> applies the enclosed
1051 directives if and only if both the given condition evaluates to true and
1052 the most recent <code class="directive"><If></code> or
1053 <code class="directive"><ElseIf></code> section in the same scope has
1054 not been applied. For example: In </p>
1056 <pre class="prettyprint lang-config"><If "-R '10.1.0.0/16'">
1059 <ElseIf "-R '10.0.0.0/8'">
1067 <p>The <code class="directive"><ElseIf></code> would match if
1068 the remote address of a request belongs to the subnet 10.0.0.0/8 but
1069 not to the subnet 10.1.0.0/16.</p>
1074 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
1075 for a complete reference and more examples.</li>
1076 <li><code class="directive"><a href="#if"><If></a></code></li>
1077 <li><code class="directive"><a href="#else"><Else></a></code></li>
1078 <li><a href="../sections.html">How <Directory>, <Location>,
1079 <Files> sections work</a> for an explanation of how these
1080 different sections are combined when a request is received.
1081 <code class="directive"><If></code>,
1082 <code class="directive"><ElseIf></code>, and
1083 <code class="directive"><Else></code> are applied last.</li>
1086 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1087 <div class="directive-section"><h2><a name="EnableMMAP" id="EnableMMAP">EnableMMAP</a> <a name="enablemmap" id="enablemmap">Directive</a></h2>
1088 <table class="directive">
1089 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use memory-mapping to read files during delivery</td></tr>
1090 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableMMAP On|Off</code></td></tr>
1091 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableMMAP On</code></td></tr>
1092 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1093 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1094 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1095 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1097 <p>This directive controls whether the <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use
1098 memory-mapping if it needs to read the contents of a file during
1099 delivery. By default, when the handling of a request requires
1100 access to the data within a file -- for example, when delivering a
1101 server-parsed file using <code class="module"><a href="../mod/mod_include.html">mod_include</a></code> -- Apache httpd
1102 memory-maps the file if the OS supports it.</p>
1104 <p>This memory-mapping sometimes yields a performance improvement.
1105 But in some environments, it is better to disable the memory-mapping
1106 to prevent operational problems:</p>
1109 <li>On some multiprocessor systems, memory-mapping can reduce the
1110 performance of the <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</li>
1111 <li>Deleting or truncating a file while <code class="program"><a href="../programs/httpd.html">httpd</a></code>
1112 has it memory-mapped can cause <code class="program"><a href="../programs/httpd.html">httpd</a></code> to
1113 crash with a segmentation fault.
1117 <p>For server configurations that are vulnerable to these problems,
1118 you should disable memory-mapping of delivered files by specifying:</p>
1120 <pre class="prettyprint lang-config">EnableMMAP Off</pre>
1123 <p>For NFS mounted files, this feature may be disabled explicitly for
1124 the offending files by specifying:</p>
1126 <pre class="prettyprint lang-config"><Directory "/path-to-nfs-files">
1128 </Directory></pre>
1132 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1133 <div class="directive-section"><h2><a name="EnableSendfile" id="EnableSendfile">EnableSendfile</a> <a name="enablesendfile" id="enablesendfile">Directive</a></h2>
1134 <table class="directive">
1135 <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>
1136 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableSendfile On|Off</code></td></tr>
1137 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableSendfile Off</code></td></tr>
1138 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1139 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1140 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1141 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1142 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Default changed to Off in
1143 version 2.3.9.</td></tr>
1145 <p>This directive controls whether <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use the
1146 sendfile support from the kernel to transmit file contents to the client.
1147 By default, when the handling of a request requires no access
1148 to the data within a file -- for example, when delivering a
1149 static file -- Apache httpd uses sendfile to deliver the file contents
1150 without ever reading the file if the OS supports it.</p>
1152 <p>This sendfile mechanism avoids separate read and send operations,
1153 and buffer allocations. But on some platforms or within some
1154 filesystems, it is better to disable this feature to avoid
1155 operational problems:</p>
1158 <li>Some platforms may have broken sendfile support that the build
1159 system did not detect, especially if the binaries were built on
1160 another box and moved to such a machine with broken sendfile
1162 <li>On Linux the use of sendfile triggers TCP-checksum
1163 offloading bugs on certain networking cards when using IPv6.</li>
1164 <li>On Linux on Itanium, <code>sendfile</code> may be unable to handle
1165 files over 2GB in size.</li>
1166 <li>With a network-mounted <code class="directive"><a href="#documentroot">DocumentRoot</a></code> (e.g., NFS, SMB, CIFS, FUSE),
1167 the kernel may be unable to serve the network file through
1171 <p>For server configurations that are not vulnerable to these problems,
1172 you may enable this feature by specifying:</p>
1174 <pre class="prettyprint lang-config">EnableSendfile On</pre>
1177 <p>For network mounted files, this feature may be disabled explicitly
1178 for the offending files by specifying:</p>
1180 <pre class="prettyprint lang-config"><Directory "/path-to-nfs-files">
1182 </Directory></pre>
1184 <p>Please note that the per-directory and .htaccess configuration
1185 of <code class="directive">EnableSendfile</code> is not supported by
1186 <code class="module"><a href="../mod/mod_cache_disk.html">mod_cache_disk</a></code>.
1187 Only global definition of <code class="directive">EnableSendfile</code>
1188 is taken into account by the module.
1192 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1193 <div class="directive-section"><h2><a name="Error" id="Error">Error</a> <a name="error" id="error">Directive</a></h2>
1194 <table class="directive">
1195 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Abort configuration parsing with a custom error message</td></tr>
1196 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Error <var>message</var></code></td></tr>
1197 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1198 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1199 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1200 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.3.9 and later</td></tr>
1202 <p>If an error can be detected within the configuration, this
1203 directive can be used to generate a custom error message, and halt
1204 configuration parsing. The typical use is for reporting required
1205 modules which are missing from the configuration.</p>
1207 <pre class="prettyprint lang-config"># Example
1208 # ensure that mod_include is loaded
1209 <IfModule !include_module>
1210 Error "mod_include is required by mod_foo. Load it with LoadModule."
1213 # ensure that exactly one of SSL,NOSSL is defined
1214 <IfDefine SSL>
1215 <IfDefine NOSSL>
1216 Error "Both SSL and NOSSL are defined. Define only one of them."
1219 <IfDefine !SSL>
1220 <IfDefine !NOSSL>
1221 Error "Either SSL or NOSSL must be defined."
1223 </IfDefine></pre>
1228 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1229 <div class="directive-section"><h2><a name="ErrorDocument" id="ErrorDocument">ErrorDocument</a> <a name="errordocument" id="errordocument">Directive</a></h2>
1230 <table class="directive">
1231 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>What the server will return to the client
1232 in case of an error</td></tr>
1233 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ErrorDocument <var>error-code</var> <var>document</var></code></td></tr>
1234 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1235 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1236 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1237 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1239 <p>In the event of a problem or error, Apache httpd can be configured
1240 to do one of four things,</p>
1243 <li>output a simple hardcoded error message</li>
1245 <li>output a customized message</li>
1247 <li>internally redirect to a local <var>URL-path</var> to handle the
1250 <li>redirect to an external <var>URL</var> to handle the
1254 <p>The first option is the default, while options 2-4 are
1255 configured using the <code class="directive">ErrorDocument</code>
1256 directive, which is followed by the HTTP response code and a URL
1257 or a message. Apache httpd will sometimes offer additional information
1258 regarding the problem/error.</p>
1260 <p>URLs can begin with a slash (/) for local web-paths (relative
1261 to the <code class="directive"><a href="#documentroot">DocumentRoot</a></code>), or be a
1262 full URL which the client can resolve. Alternatively, a message
1263 can be provided to be displayed by the browser. Examples:</p>
1265 <pre class="prettyprint lang-config">ErrorDocument 500 http://foo.example.com/cgi-bin/tester
1266 ErrorDocument 404 /cgi-bin/bad_urls.pl
1267 ErrorDocument 401 /subscription_info.html
1268 ErrorDocument 403 "Sorry can't allow you access today"
1269 ErrorDocument 403 Forbidden!</pre>
1272 <p>Additionally, the special value <code>default</code> can be used
1273 to specify Apache httpd's simple hardcoded message. While not required
1274 under normal circumstances, <code>default</code> will restore
1275 Apache httpd's simple hardcoded message for configurations that would
1276 otherwise inherit an existing <code class="directive">ErrorDocument</code>.</p>
1278 <pre class="prettyprint lang-config">ErrorDocument 404 /cgi-bin/bad_urls.pl
1280 <Directory /web/docs>
1281 ErrorDocument 404 default
1282 </Directory></pre>
1285 <p>Note that when you specify an <code class="directive">ErrorDocument</code>
1286 that points to a remote URL (ie. anything with a method such as
1287 <code>http</code> in front of it), Apache HTTP Server will send a redirect to the
1288 client to tell it where to find the document, even if the
1289 document ends up being on the same server. This has several
1290 implications, the most important being that the client will not
1291 receive the original error status code, but instead will
1292 receive a redirect status code. This in turn can confuse web
1293 robots and other clients which try to determine if a URL is
1294 valid using the status code. In addition, if you use a remote
1295 URL in an <code>ErrorDocument 401</code>, the client will not
1296 know to prompt the user for a password since it will not
1297 receive the 401 status code. Therefore, <strong>if you use an
1298 <code>ErrorDocument 401</code> directive then it must refer to a local
1299 document.</strong></p>
1301 <p>Microsoft Internet Explorer (MSIE) will by default ignore
1302 server-generated error messages when they are "too small" and substitute
1303 its own "friendly" error messages. The size threshold varies depending on
1304 the type of error, but in general, if you make your error document
1305 greater than 512 bytes, then MSIE will show the server-generated
1306 error rather than masking it. More information is available in
1307 Microsoft Knowledge Base article <a href="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q294807">Q294807</a>.</p>
1309 <p>Although most error messages can be overridden, there are certain
1310 circumstances where the internal messages are used regardless of the
1311 setting of <code class="directive"><a href="#errordocument">ErrorDocument</a></code>. In
1312 particular, if a malformed request is detected, normal request processing
1313 will be immediately halted and the internal error message returned.
1314 This is necessary to guard against security problems caused by
1317 <p>If you are using mod_proxy, you may wish to enable
1318 <code class="directive"><a href="../mod/mod_proxy.html#proxyerroroverride">ProxyErrorOverride</a></code> so that you can provide
1319 custom error messages on behalf of your Origin servers. If you don't enable ProxyErrorOverride,
1320 Apache httpd will not generate custom error documents for proxied content.</p>
1324 <li><a href="../custom-error.html">documentation of
1325 customizable responses</a></li>
1328 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1329 <div class="directive-section"><h2><a name="ErrorLog" id="ErrorLog">ErrorLog</a> <a name="errorlog" id="errorlog">Directive</a></h2>
1330 <table class="directive">
1331 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Location where the server will log errors</td></tr>
1332 <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>
1333 <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>
1334 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1335 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1336 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1338 <p>The <code class="directive">ErrorLog</code> directive sets the name of
1339 the file to which the server will log any errors it encounters. If
1340 the <var>file-path</var> is not absolute then it is assumed to be
1341 relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1343 <pre class="prettyprint lang-config">ErrorLog "/var/log/httpd/error_log"</pre>
1346 <p>If the <var>file-path</var>
1347 begins with a pipe character "<code>|</code>" then it is assumed to be a
1348 command to spawn to handle the error log.</p>
1350 <pre class="prettyprint lang-config">ErrorLog "|/usr/local/bin/httpd_errors"</pre>
1353 <p>See the notes on <a href="../logs.html#piped">piped logs</a> for
1354 more information.</p>
1356 <p>Using <code>syslog</code> instead of a filename enables logging
1357 via syslogd(8) if the system supports it. The default is to use
1358 syslog facility <code>local7</code>, but you can override this by
1359 using the <code>syslog:<var>facility</var></code> syntax where
1360 <var>facility</var> can be one of the names usually documented in
1361 syslog(1). The facility is effectively global, and if it is changed
1362 in individual virtual hosts, the final facility specified affects the
1365 <pre class="prettyprint lang-config">ErrorLog syslog:user</pre>
1368 <p>SECURITY: See the <a href="../misc/security_tips.html#serverroot">security tips</a>
1369 document for details on why your security could be compromised
1370 if the directory where log files are stored is writable by
1371 anyone other than the user that starts the server.</p>
1372 <div class="warning"><h3>Note</h3>
1373 <p>When entering a file path on non-Unix platforms, care should be taken
1374 to make sure that only forward slashes are used even though the platform
1375 may allow the use of back slashes. In general it is a good idea to always
1376 use forward slashes throughout the configuration files.</p>
1381 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1382 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1385 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1386 <div class="directive-section"><h2><a name="ErrorLogFormat" id="ErrorLogFormat">ErrorLogFormat</a> <a name="errorlogformat" id="errorlogformat">Directive</a></h2>
1387 <table class="directive">
1388 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Format specification for error log entries</td></tr>
1389 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code> ErrorLogFormat [connection|request] <var>format</var></code></td></tr>
1390 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1391 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1392 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1394 <p><code class="directive">ErrorLogFormat</code> allows to specify what
1395 supplementary information is logged in the error log in addition to the
1396 actual log message.</p>
1398 <pre class="prettyprint lang-config">#Simple example
1399 ErrorLogFormat "[%t] [%l] [pid %P] %F: %E: [client %a] %M"</pre>
1402 <p>Specifying <code>connection</code> or <code>request</code> as first
1403 parameter allows to specify additional formats, causing additional
1404 information to be logged when the first message is logged for a specific
1405 connection or request, respectively. This additional information is only
1406 logged once per connection/request. If a connection or request is processed
1407 without causing any log message, the additional information is not logged
1410 <p>It can happen that some format string items do not produce output. For
1411 example, the Referer header is only present if the log message is
1412 associated to a request and the log message happens at a time when the
1413 Referer header has already been read from the client. If no output is
1414 produced, the default behavior is to delete everything from the preceding
1415 space character to the next space character. This means the log line is
1416 implicitly divided into fields on non-whitespace to whitespace transitions.
1417 If a format string item does not produce output, the whole field is
1418 omitted. For example, if the remote address <code>%a</code> in the log
1419 format <code>[%t] [%l] [%a] %M </code> is not available, the surrounding
1420 brackets are not logged either. Space characters can be escaped with a
1421 backslash to prevent them from delimiting a field. The combination '% '
1422 (percent space) is a zero-width field delimiter that does not produce any
1425 <p>The above behavior can be changed by adding modifiers to the format
1426 string item. A <code>-</code> (minus) modifier causes a minus to be logged if the
1427 respective item does not produce any output. In once-per-connection/request
1428 formats, it is also possible to use the <code>+</code> (plus) modifier. If an
1429 item with the plus modifier does not produce any output, the whole line is
1432 <p>A number as modifier can be used to assign a log severity level to a
1433 format item. The item will only be logged if the severity of the log
1434 message is not higher than the specified log severity level. The number can
1435 range from 1 (alert) over 4 (warn) and 7 (debug) to 15 (trace8).</p>
1437 <p>For example, here's what would happen if you added modifiers to
1438 the <code>%{Referer}i</code> token, which logs the
1439 <code>Referer</code> request header.</p>
1441 <table class="bordered"><tr class="header"><th>Modified Token</th><th>Meaning</th></tr>
1443 <td><code>%-{Referer}i</code></td>
1444 <td>Logs a <code>-</code> if <code>Referer</code> is not set.</td>
1447 <td><code>%+{Referer}i</code></td>
1448 <td>Omits the entire line if <code>Referer</code> is not set.</td>
1451 <td><code>%4{Referer}i</code></td>
1452 <td>Logs the <code>Referer</code> only if the log message severity
1453 is higher than 4.</td>
1457 <p>Some format string items accept additional parameters in braces.</p>
1459 <table class="bordered"><tr class="header"><th>Format String</th> <th>Description</th></tr>
1460 <tr><td><code>%%</code></td>
1461 <td>The percent sign</td></tr>
1462 <tr class="odd"><td><code>%a</code></td>
1463 <td>Client IP address and port of the request</td></tr>
1464 <tr><td><code>%{c}a</code></td>
1465 <td>Underlying peer IP address and port of the connection (see the
1466 <code class="module"><a href="../mod/mod_remoteip.html">mod_remoteip</a></code> module)</td></tr>
1467 <tr class="odd"><td><code>%A</code></td>
1468 <td>Local IP-address and port</td></tr>
1469 <tr><td><code>%{<em>name</em>}e</code></td>
1470 <td>Request environment variable <em>name</em></td></tr>
1471 <tr class="odd"><td><code>%E</code></td>
1472 <td>APR/OS error status code and string</td></tr>
1473 <tr><td><code>%F</code></td>
1474 <td>Source file name and line number of the log call</td></tr>
1475 <tr class="odd"><td><code>%{<em>name</em>}i</code></td>
1476 <td>Request header <em>name</em></td></tr>
1477 <tr><td><code>%k</code></td>
1478 <td>Number of keep-alive requests on this connection</td></tr>
1479 <tr class="odd"><td><code>%l</code></td>
1480 <td>Loglevel of the message</td></tr>
1481 <tr><td><code>%L</code></td>
1482 <td>Log ID of the request</td></tr>
1483 <tr class="odd"><td><code>%{c}L</code></td>
1484 <td>Log ID of the connection</td></tr>
1485 <tr><td><code>%{C}L</code></td>
1486 <td>Log ID of the connection if used in connection scope, empty otherwise</td></tr>
1487 <tr class="odd"><td><code>%m</code></td>
1488 <td>Name of the module logging the message</td></tr>
1489 <tr><td><code>%M</code></td>
1490 <td>The actual log message</td></tr>
1491 <tr class="odd"><td><code>%{<em>name</em>}n</code></td>
1492 <td>Request note <em>name</em></td></tr>
1493 <tr><td><code>%P</code></td>
1494 <td>Process ID of current process</td></tr>
1495 <tr class="odd"><td><code>%T</code></td>
1496 <td>Thread ID of current thread</td></tr>
1497 <tr><td><code>%{g}T</code></td>
1498 <td>System unique thread ID of current thread (the same ID as
1499 displayed by e.g. <code>top</code>; currently Linux only)</td></tr>
1500 <tr class="odd"><td><code>%t</code></td>
1501 <td>The current time</td></tr>
1502 <tr><td><code>%{u}t</code></td>
1503 <td>The current time including micro-seconds</td></tr>
1504 <tr class="odd"><td><code>%{cu}t</code></td>
1505 <td>The current time in compact ISO 8601 format, including
1506 micro-seconds</td></tr>
1507 <tr><td><code>%v</code></td>
1508 <td>The canonical <code class="directive"><a href="#servername">ServerName</a></code>
1509 of the current server.</td></tr>
1510 <tr class="odd"><td><code>%V</code></td>
1511 <td>The server name of the server serving the request according to the
1512 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code>
1514 <tr><td><code>\ </code> (backslash space)</td>
1515 <td>Non-field delimiting space</td></tr>
1516 <tr class="odd"><td><code>% </code> (percent space)</td>
1517 <td>Field delimiter (no output)</td></tr>
1520 <p>The log ID format <code>%L</code> produces a unique id for a connection
1521 or request. This can be used to correlate which log lines belong to the
1522 same connection or request, which request happens on which connection.
1523 A <code>%L</code> format string is also available in
1524 <code class="module"><a href="../mod/mod_log_config.html">mod_log_config</a></code>, to allow to correlate access log entries
1525 with error log lines. If <code class="module"><a href="../mod/mod_unique_id.html">mod_unique_id</a></code> is loaded, its
1526 unique id will be used as log ID for requests.</p>
1528 <pre class="prettyprint lang-config">#Example (default format for threaded MPMs)
1529 ErrorLogFormat "[%{u}t] [%-m:%l] [pid %P:tid %T] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"</pre>
1532 <p>This would result in error messages such as:</p>
1534 <div class="example"><p><code>
1535 [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
1538 <p>Notice that, as discussed above, some fields are omitted
1539 entirely because they are not defined.</p>
1541 <pre class="prettyprint lang-config">#Example (similar to the 2.2.x format)
1542 ErrorLogFormat "[%t] [%l] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i"</pre>
1545 <pre class="prettyprint lang-config">#Advanced example with request/connection log IDs
1546 ErrorLogFormat "[%{uc}t] [%-m:%-l] [R:%L] [C:%{C}L] %7F: %E: %M"
1547 ErrorLogFormat request "[%{uc}t] [R:%L] Request %k on C:%{c}L pid:%P tid:%T"
1548 ErrorLogFormat request "[%{uc}t] [R:%L] UA:'%+{User-Agent}i'"
1549 ErrorLogFormat request "[%{uc}t] [R:%L] Referer:'%+{Referer}i'"
1550 ErrorLogFormat connection "[%{uc}t] [C:%{c}L] local\ %a remote\ %A"</pre>
1556 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
1557 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1558 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1561 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1562 <div class="directive-section"><h2><a name="ExtendedStatus" id="ExtendedStatus">ExtendedStatus</a> <a name="extendedstatus" id="extendedstatus">Directive</a></h2>
1563 <table class="directive">
1564 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Keep track of extended status information for each
1566 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ExtendedStatus On|Off</code></td></tr>
1567 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ExtendedStatus Off[*]</code></td></tr>
1568 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
1569 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1570 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1572 <p>This option tracks additional data per worker about the
1573 currently executing request, and a utilization summary; you
1574 can see these variables during runtime by configuring
1575 <code class="module"><a href="../mod/mod_status.html">mod_status</a></code>. Note that other modules may
1576 rely on this scoreboard.</p>
1578 <p>This setting applies to the entire server, and cannot be
1579 enabled or disabled on a virtualhost-by-virtualhost basis.
1580 The collection of extended status information can slow down
1581 the server. Also note that this setting cannot be changed
1582 during a graceful restart.</p>
1585 <p>Note that loading <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> will change
1586 the default behavior to ExtendedStatus On, while other
1587 third party modules may do the same. Such modules rely on
1588 collecting detailed information about the state of all workers.
1589 The default is changed by <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> beginning
1590 with version 2.3.6; the previous default was always Off.</p>
1595 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1596 <div class="directive-section"><h2><a name="FileETag" id="FileETag">FileETag</a> <a name="fileetag" id="fileetag">Directive</a></h2>
1597 <table class="directive">
1598 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>File attributes used to create the ETag
1599 HTTP response header for static files</td></tr>
1600 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>FileETag <var>component</var> ...</code></td></tr>
1601 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>FileETag MTime Size</code></td></tr>
1602 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1603 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1604 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1605 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1606 <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
1610 The <code class="directive">FileETag</code> directive configures the file
1611 attributes that are used to create the <code>ETag</code> (entity
1612 tag) response header field when the document is based on a static file.
1613 (The <code>ETag</code> value is used in cache management to save
1614 network bandwidth.) The
1615 <code class="directive">FileETag</code> directive allows you to choose
1616 which of these -- if any -- should be used. The recognized keywords are:
1620 <dt><strong>INode</strong></dt>
1621 <dd>The file's i-node number will be included in the calculation</dd>
1622 <dt><strong>MTime</strong></dt>
1623 <dd>The date and time the file was last modified will be included</dd>
1624 <dt><strong>Size</strong></dt>
1625 <dd>The number of bytes in the file will be included</dd>
1626 <dt><strong>All</strong></dt>
1627 <dd>All available fields will be used. This is equivalent to:
1628 <pre class="prettyprint lang-config">FileETag INode MTime Size</pre>
1630 <dt><strong>None</strong></dt>
1631 <dd>If a document is file-based, no <code>ETag</code> field will be
1632 included in the response</dd>
1635 <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
1636 keywords may be prefixed with either <code>+</code> or <code>-</code>,
1637 which allow changes to be made to the default setting inherited
1638 from a broader scope. Any keyword appearing without such a prefix
1639 immediately and completely cancels the inherited setting.</p>
1641 <p>If a directory's configuration includes
1642 <code>FileETag INode MTime Size</code>, and a
1643 subdirectory's includes <code>FileETag -INode</code>,
1644 the setting for that subdirectory (which will be inherited by
1645 any sub-subdirectories that don't override it) will be equivalent to
1646 <code>FileETag MTime Size</code>.</p>
1647 <div class="warning"><h3>Warning</h3>
1648 Do not change the default for directories or locations that have WebDAV
1649 enabled and use <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> as a storage provider.
1650 <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> uses <code>MTime Size</code>
1651 as a fixed format for <code>ETag</code> comparisons on conditional requests.
1652 These conditional requests will break if the <code>ETag</code> format is
1653 changed via <code class="directive">FileETag</code>.
1655 <div class="note"><h3>Server Side Includes</h3>
1656 An ETag is not generated for responses parsed by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>,
1657 since the response entity can change without a change of the INode, MTime, or Size
1658 of the static file with embedded SSI directives.
1663 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1664 <div class="directive-section"><h2><a name="Files" id="Files"><Files></a> <a name="files" id="files">Directive</a></h2>
1665 <table class="directive">
1666 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to matched
1668 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Files <var>filename</var>> ... </Files></code></td></tr>
1669 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1670 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1671 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1672 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1674 <p>The <code class="directive"><Files></code> directive
1675 limits the scope of the enclosed directives by filename. It is comparable
1676 to the <code class="directive"><a href="#directory"><Directory></a></code>
1677 and <code class="directive"><a href="#location"><Location></a></code>
1678 directives. It should be matched with a <code></Files></code>
1679 directive. The directives given within this section will be applied to
1680 any object with a basename (last component of filename) matching the
1681 specified filename. <code class="directive"><Files></code>
1682 sections are processed in the order they appear in the
1683 configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
1684 <code>.htaccess</code> files are read, but before <code class="directive"><a href="#location"><Location></a></code> sections. Note
1685 that <code class="directive"><Files></code> can be nested
1686 inside <code class="directive"><a href="#directory"><Directory></a></code> sections to restrict the
1687 portion of the filesystem they apply to.</p>
1689 <p>The <var>filename</var> argument should include a filename, or
1690 a wild-card string, where <code>?</code> matches any single character,
1691 and <code>*</code> matches any sequences of characters.</p>
1692 <pre class="prettyprint lang-config"><Files "cat.html">
1693 # Insert stuff that applies to cat.html here
1696 <Files "?at.*">
1697 # This would apply to cat.html, bat.html, hat.php and so on.
1698 </Files></pre>
1700 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
1701 can also be used, with the addition of the
1702 <code>~</code> character. For example:</p>
1704 <pre class="prettyprint lang-config"><Files ~ "\.(gif|jpe?g|png)$">
1706 </Files></pre>
1709 <p>would match most common Internet graphics formats. <code class="directive"><a href="#filesmatch"><FilesMatch></a></code> is preferred,
1712 <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
1713 <code>.htaccess</code> files. This allows users to control access to
1714 their own files, at a file-by-file level.</p>
1719 <li><a href="../sections.html">How <Directory>, <Location>
1720 and <Files> sections work</a> for an explanation of how these
1721 different sections are combined when a request is received</li>
1724 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1725 <div class="directive-section"><h2><a name="FilesMatch" id="FilesMatch"><FilesMatch></a> <a name="filesmatch" id="filesmatch">Directive</a></h2>
1726 <table class="directive">
1727 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to regular-expression matched
1729 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><FilesMatch <var>regex</var>> ... </FilesMatch></code></td></tr>
1730 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1731 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1732 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1733 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1735 <p>The <code class="directive"><FilesMatch></code> directive
1736 limits the scope of the enclosed directives by filename, just as the
1737 <code class="directive"><a href="#files"><Files></a></code> directive
1738 does. However, it accepts a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular
1739 expression</a>. For example:</p>
1741 <pre class="prettyprint lang-config"><FilesMatch "\.(gif|jpe?g|png)$">
1743 </FilesMatch></pre>
1746 <p>would match most common Internet graphics formats.</p>
1748 <p>From 2.4.8 onwards, named groups and backreferences are captured and
1749 written to the environment with the corresponding name prefixed with
1750 "MATCH_" and in upper case. This allows elements of files to be referenced
1751 from within <a href="../expr.html">expressions</a> and modules like
1752 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
1753 (unnamed) backreferences are ignored. Use named groups instead.</p>
1755 <pre class="prettyprint lang-config"><FilesMatch ^(?<sitename>[^/]+)>
1756 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
1757 </FilesMatch></pre>
1762 <li><a href="../sections.html">How <Directory>, <Location>
1763 and <Files> sections work</a> for an explanation of how these
1764 different sections are combined when a request is received</li>
1767 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1768 <div class="directive-section"><h2><a name="ForceType" id="ForceType">ForceType</a> <a name="forcetype" id="forcetype">Directive</a></h2>
1769 <table class="directive">
1770 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be served with the specified
1771 media type in the HTTP Content-Type header field</td></tr>
1772 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ForceType <var>media-type</var>|None</code></td></tr>
1773 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
1774 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1775 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1776 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1778 <p>When placed into an <code>.htaccess</code> file or a
1779 <code class="directive"><a href="#directory"><Directory></a></code>, or
1780 <code class="directive"><a href="#location"><Location></a></code> or
1781 <code class="directive"><a href="#files"><Files></a></code>
1782 section, this directive forces all matching files to be served
1783 with the content type identification given by
1784 <var>media-type</var>. For example, if you had a directory full of
1785 GIF files, but did not want to label them all with <code>.gif</code>,
1786 you might want to use:</p>
1788 <pre class="prettyprint lang-config">ForceType image/gif</pre>
1791 <p>Note that this directive overrides other indirect media type
1792 associations defined in mime.types or via the
1793 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code>.</p>
1795 <p>You can also override more general
1796 <code class="directive">ForceType</code> settings
1797 by using the value of <code>None</code>:</p>
1799 <pre class="prettyprint lang-config"># force all files to be image/gif:
1800 <Location /images>
1804 # but normal mime-type associations here:
1805 <Location /images/mixed>
1807 </Location></pre>
1810 <p>This directive primarily overrides the content types generated for
1811 static files served out of the filesystem. For resources other than
1812 static files, where the generator of the response typically specifies
1813 a Content-Type, this directive has no effect.</p>
1817 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1818 <div class="directive-section"><h2><a name="GprofDir" id="GprofDir">GprofDir</a> <a name="gprofdir" id="gprofdir">Directive</a></h2>
1819 <table class="directive">
1820 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory to write gmon.out profiling data to. </td></tr>
1821 <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>
1822 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1823 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1824 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1826 <p>When the server has been compiled with gprof profiling support,
1827 <code class="directive">GprofDir</code> causes <code>gmon.out</code> files to
1828 be written to the specified directory when the process exits. If the
1829 argument ends with a percent symbol ('%'), subdirectories are created
1830 for each process id.</p>
1832 <p>This directive currently only works with the <code class="module"><a href="../mod/prefork.html">prefork</a></code>
1836 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1837 <div class="directive-section"><h2><a name="HostnameLookups" id="HostnameLookups">HostnameLookups</a> <a name="hostnamelookups" id="hostnamelookups">Directive</a></h2>
1838 <table class="directive">
1839 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables DNS lookups on client IP addresses</td></tr>
1840 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>HostnameLookups On|Off|Double</code></td></tr>
1841 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>HostnameLookups Off</code></td></tr>
1842 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1843 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1844 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1846 <p>This directive enables DNS lookups so that host names can be
1847 logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
1848 The value <code>Double</code> refers to doing double-reverse
1849 DNS lookup. That is, after a reverse lookup is performed, a forward
1850 lookup is then performed on that result. At least one of the IP
1851 addresses in the forward lookup must match the original
1852 address. (In "tcpwrappers" terminology this is called
1853 <code>PARANOID</code>.)</p>
1855 <p>Regardless of the setting, when <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code> is
1856 used for controlling access by hostname, a double reverse lookup
1857 will be performed. This is necessary for security. Note that the
1858 result of this double-reverse isn't generally available unless you
1859 set <code>HostnameLookups Double</code>. For example, if only
1860 <code>HostnameLookups On</code> and a request is made to an object
1861 that is protected by hostname restrictions, regardless of whether
1862 the double-reverse fails or not, CGIs will still be passed the
1863 single-reverse result in <code>REMOTE_HOST</code>.</p>
1865 <p>The default is <code>Off</code> in order to save the network
1866 traffic for those sites that don't truly need the reverse
1867 lookups done. It is also better for the end users because they
1868 don't have to suffer the extra latency that a lookup entails.
1869 Heavily loaded sites should leave this directive
1870 <code>Off</code>, since DNS lookups can take considerable
1871 amounts of time. The utility <code class="program"><a href="../programs/logresolve.html">logresolve</a></code>, compiled by
1872 default to the <code>bin</code> subdirectory of your installation
1873 directory, can be used to look up host names from logged IP addresses
1876 <p>Finally, if you have <a href="mod_authz_host.html#reqhost">hostname-based Require
1877 directives</a>, a hostname lookup will be performed regardless of
1878 the setting of <code>HostnameLookups</code>.</p>
1881 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1882 <div class="directive-section"><h2><a name="If" id="If"><If></a> <a name="if" id="if">Directive</a></h2>
1883 <table class="directive">
1884 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is
1885 satisfied by a request at runtime</td></tr>
1886 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><If <var>expression</var>> ... </If></code></td></tr>
1887 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1888 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1889 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1890 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1892 <p>The <code class="directive"><If></code> directive
1893 evaluates an expression at runtime, and applies the enclosed
1894 directives if and only if the expression evaluates to true.
1897 <pre class="prettyprint lang-config"><If "-z req('Host')"></pre>
1900 <p>would match HTTP/1.0 requests without a <var>Host:</var> header.
1901 Expressions may contain various shell-like operators for string
1902 comparison (<code>==</code>, <code>!=</code>, <code><</code>, ...),
1903 integer comparison (<code>-eq</code>, <code>-ne</code>, ...),
1904 and others (<code>-n</code>, <code>-z</code>, <code>-f</code>, ...).
1905 It is also possible to use regular expressions, </p>
1907 <pre class="prettyprint lang-config"><If "%{QUERY_STRING} =~ /(delete|commit)=.*?elem/"></pre>
1910 <p>shell-like pattern matches and many other operations. These operations
1911 can be done on request headers (<code>req</code>), environment variables
1912 (<code>env</code>), and a large number of other properties. The full
1913 documentation is available in <a href="../expr.html">Expressions in
1914 Apache HTTP Server</a>.</p>
1916 <p>Only directives that support the <a href="directive-dict.html#Context">directory context</a> can be used within this configuration section.</p>
1921 <li><a href="../expr.html">Expressions in Apache HTTP Server</a>,
1922 for a complete reference and more examples.</li>
1923 <li><code class="directive"><a href="#elseif"><ElseIf></a></code></li>
1924 <li><code class="directive"><a href="#else"><Else></a></code></li>
1925 <li><a href="../sections.html">How <Directory>, <Location>,
1926 <Files> sections work</a> for an explanation of how these
1927 different sections are combined when a request is received.
1928 <code class="directive"><If></code>,
1929 <code class="directive"><ElseIf></code>, and
1930 <code class="directive"><Else></code> are applied last.</li>
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="IfDefine" id="IfDefine"><IfDefine></a> <a name="ifdefine" id="ifdefine">Directive</a></h2>
1935 <table class="directive">
1936 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that will be processed only
1937 if a test is true at startup</td></tr>
1938 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfDefine [!]<var>parameter-name</var>> ...
1939 </IfDefine></code></td></tr>
1940 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1941 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1942 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1943 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1945 <p>The <code><IfDefine <var>test</var>>...</IfDefine>
1946 </code> section is used to mark directives that are conditional. The
1947 directives within an <code class="directive"><IfDefine></code>
1948 section are only processed if the <var>test</var> is true. If <var>
1949 test</var> is false, everything between the start and end markers is
1952 <p>The <var>test</var> in the <code class="directive"><IfDefine></code> section directive can be one of two forms:</p>
1955 <li><var>parameter-name</var></li>
1957 <li><code>!</code><var>parameter-name</var></li>
1960 <p>In the former case, the directives between the start and end
1961 markers are only processed if the parameter named
1962 <var>parameter-name</var> is defined. The second format reverses
1963 the test, and only processes the directives if
1964 <var>parameter-name</var> is <strong>not</strong> defined.</p>
1966 <p>The <var>parameter-name</var> argument is a define as given on the
1967 <code class="program"><a href="../programs/httpd.html">httpd</a></code> command line via <code>-D<var>parameter</var>
1968 </code> at the time the server was started or by the <code class="directive"><a href="#define">Define</a></code> directive.</p>
1970 <p><code class="directive"><IfDefine></code> sections are
1971 nest-able, which can be used to implement simple
1972 multiple-parameter tests. Example:</p>
1974 <div class="example"><p><code>httpd -DReverseProxy -DUseCache -DMemCache ...</code></p></div>
1975 <pre class="prettyprint lang-config"><IfDefine ReverseProxy>
1976 LoadModule proxy_module modules/mod_proxy.so
1977 LoadModule proxy_http_module modules/mod_proxy_http.so
1978 <IfDefine UseCache>
1979 LoadModule cache_module modules/mod_cache.so
1980 <IfDefine MemCache>
1981 LoadModule mem_cache_module modules/mod_mem_cache.so
1983 <IfDefine !MemCache>
1984 LoadModule cache_disk_module modules/mod_cache_disk.so
1987 </IfDefine></pre>
1991 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1992 <div class="directive-section"><h2><a name="IfModule" id="IfModule"><IfModule></a> <a name="ifmodule" id="ifmodule">Directive</a></h2>
1993 <table class="directive">
1994 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that are processed conditional on the
1995 presence or absence of a specific module</td></tr>
1996 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfModule [!]<var>module-file</var>|<var>module-identifier</var>> ...
1997 </IfModule></code></td></tr>
1998 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1999 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2000 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2001 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2002 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Module identifiers are available in version 2.1 and
2005 <p>The <code><IfModule <var>test</var>>...</IfModule></code>
2006 section is used to mark directives that are conditional on the presence of
2007 a specific module. The directives within an <code class="directive"><IfModule></code> section are only processed if the <var>test</var>
2008 is true. If <var>test</var> is false, everything between the start and
2009 end markers is ignored.</p>
2011 <p>The <var>test</var> in the <code class="directive"><IfModule></code> section directive can be one of two forms:</p>
2014 <li><var>module</var></li>
2016 <li>!<var>module</var></li>
2019 <p>In the former case, the directives between the start and end
2020 markers are only processed if the module named <var>module</var>
2021 is included in Apache httpd -- either compiled in or
2022 dynamically loaded using <code class="directive"><a href="../mod/mod_so.html#loadmodule">LoadModule</a></code>. The second format reverses the test,
2023 and only processes the directives if <var>module</var> is
2024 <strong>not</strong> included.</p>
2026 <p>The <var>module</var> argument can be either the module identifier or
2027 the file name of the module, at the time it was compiled. For example,
2028 <code>rewrite_module</code> is the identifier and
2029 <code>mod_rewrite.c</code> is the file name. If a module consists of
2030 several source files, use the name of the file containing the string
2031 <code>STANDARD20_MODULE_STUFF</code>.</p>
2033 <p><code class="directive"><IfModule></code> sections are
2034 nest-able, which can be used to implement simple multiple-module
2037 <div class="note">This section should only be used if you need to have one
2038 configuration file that works whether or not a specific module
2039 is available. In normal operation, directives need not be
2040 placed in <code class="directive"><IfModule></code>
2044 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2045 <div class="directive-section"><h2><a name="Include" id="Include">Include</a> <a name="include" id="include">Directive</a></h2>
2046 <table class="directive">
2047 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2048 the server configuration files</td></tr>
2049 <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>
2050 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2051 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2052 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2053 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Directory
2054 wildcard matching available in 2.3.6 and later</td></tr>
2056 <p>This directive allows inclusion of other configuration files
2057 from within the server configuration files.</p>
2059 <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used
2060 in the filename or directory parts of the path to include several files
2061 at once, in alphabetical order. In addition, if
2062 <code class="directive">Include</code> points to a directory, rather than a file,
2063 Apache httpd will read all files in that directory and any subdirectory.
2064 However, including entire directories is not recommended, because it is
2065 easy to accidentally leave temporary files in a directory that can cause
2066 <code class="program"><a href="../programs/httpd.html">httpd</a></code> to fail. Instead, we encourage you to use the
2067 wildcard syntax shown below, to include files that match a particular
2068 pattern, such as *.conf, for example.</p>
2070 <p>The <code class="directive"><a href="#include">Include</a></code> directive will
2071 <strong>fail with an error</strong> if a wildcard expression does not
2072 match any file. The <code class="directive"><a href="#includeoptional">IncludeOptional</a></code>
2073 directive can be used if non-matching wildcards should be ignored.</p>
2075 <p>The file path specified may be an absolute path, or may be relative
2076 to the <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory.</p>
2080 <pre class="prettyprint lang-config">Include /usr/local/apache2/conf/ssl.conf
2081 Include /usr/local/apache2/conf/vhosts/*.conf</pre>
2084 <p>Or, providing paths relative to your <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory:</p>
2086 <pre class="prettyprint lang-config">Include conf/ssl.conf
2087 Include conf/vhosts/*.conf</pre>
2090 <p>Wildcards may be included in the directory or file portion of the
2091 path. This example will fail if there is no subdirectory in conf/vhosts
2092 that contains at least one *.conf file:</p>
2094 <pre class="prettyprint lang-config">Include conf/vhosts/*/*.conf</pre>
2097 <p>Alternatively, the following command will just be ignored in case of
2098 missing files or directories:</p>
2100 <pre class="prettyprint lang-config">IncludeOptional conf/vhosts/*/*.conf</pre>
2106 <li><code class="directive"><a href="#includeoptional">IncludeOptional</a></code></li>
2107 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2110 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2111 <div class="directive-section"><h2><a name="IncludeOptional" id="IncludeOptional">IncludeOptional</a> <a name="includeoptional" id="includeoptional">Directive</a></h2>
2112 <table class="directive">
2113 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
2114 the server configuration files</td></tr>
2115 <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>
2116 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2117 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2118 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2119 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in 2.3.6 and later</td></tr>
2121 <p>This directive allows inclusion of other configuration files
2122 from within the server configuration files. It works identically to the
2123 <code class="directive"><a href="#include">Include</a></code> directive, with the
2124 exception that if wildcards do not match any file or directory, the
2125 <code class="directive"><a href="#includeoptional">IncludeOptional</a></code> directive will be
2126 silently ignored instead of causing an error.</p>
2130 <li><code class="directive"><a href="#include">Include</a></code></li>
2131 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
2134 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2135 <div class="directive-section"><h2><a name="KeepAlive" id="KeepAlive">KeepAlive</a> <a name="keepalive" id="keepalive">Directive</a></h2>
2136 <table class="directive">
2137 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables HTTP persistent connections</td></tr>
2138 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAlive On|Off</code></td></tr>
2139 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAlive On</code></td></tr>
2140 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2141 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2142 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2144 <p>The Keep-Alive extension to HTTP/1.0 and the persistent
2145 connection feature of HTTP/1.1 provide long-lived HTTP sessions
2146 which allow multiple requests to be sent over the same TCP
2147 connection. In some cases this has been shown to result in an
2148 almost 50% speedup in latency times for HTML documents with
2149 many images. To enable Keep-Alive connections, set
2150 <code>KeepAlive On</code>.</p>
2152 <p>For HTTP/1.0 clients, Keep-Alive connections will only be
2153 used if they are specifically requested by a client. In
2154 addition, a Keep-Alive connection with an HTTP/1.0 client can
2155 only be used when the length of the content is known in
2156 advance. This implies that dynamic content such as CGI output,
2157 SSI pages, and server-generated directory listings will
2158 generally not use Keep-Alive connections to HTTP/1.0 clients.
2159 For HTTP/1.1 clients, persistent connections are the default
2160 unless otherwise specified. If the client requests it, chunked
2161 encoding will be used in order to send content of unknown
2162 length over persistent connections.</p>
2164 <p>When a client uses a Keep-Alive connection it will be counted
2165 as a single "request" for the <code class="directive"><a href="../mod/mpm_common.html#maxconnectionsperchild">MaxConnectionsPerChild</a></code> directive, regardless
2166 of how many requests are sent using the connection.</p>
2170 <li><code class="directive"><a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></code></li>
2173 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2174 <div class="directive-section"><h2><a name="KeepAliveTimeout" id="KeepAliveTimeout">KeepAliveTimeout</a> <a name="keepalivetimeout" id="keepalivetimeout">Directive</a></h2>
2175 <table class="directive">
2176 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for subsequent
2177 requests on a persistent connection</td></tr>
2178 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAliveTimeout <var>num</var>[ms]</code></td></tr>
2179 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAliveTimeout 5</code></td></tr>
2180 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2181 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2182 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2184 <p>The number of seconds Apache httpd will wait for a subsequent
2185 request before closing the connection. By adding a postfix of ms the
2186 timeout can be also set in milliseconds. Once a request has been
2187 received, the timeout value specified by the
2188 <code class="directive"><a href="#timeout">Timeout</a></code> directive applies.</p>
2190 <p>Setting <code class="directive">KeepAliveTimeout</code> to a high value
2191 may cause performance problems in heavily loaded servers. The
2192 higher the timeout, the more server processes will be kept
2193 occupied waiting on connections with idle clients.</p>
2195 <p>In a name-based virtual host context, the value of the first
2196 defined virtual host best matching the local IP and port will be used.</p>
2199 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2200 <div class="directive-section"><h2><a name="Limit" id="Limit"><Limit></a> <a name="limit" id="limit">Directive</a></h2>
2201 <table class="directive">
2202 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict enclosed access controls to only certain HTTP
2204 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Limit <var>method</var> [<var>method</var>] ... > ...
2205 </Limit></code></td></tr>
2206 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2207 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2208 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2209 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2211 <p>Access controls are normally effective for
2212 <strong>all</strong> access methods, and this is the usual
2213 desired behavior. <strong>In the general case, access control
2214 directives should not be placed within a
2215 <code class="directive"><Limit></code> section.</strong></p>
2217 <p>The purpose of the <code class="directive"><Limit></code>
2218 directive is to restrict the effect of the access controls to the
2219 nominated HTTP methods. For all other methods, the access
2220 restrictions that are enclosed in the <code class="directive"><Limit></code> bracket <strong>will have no
2221 effect</strong>. The following example applies the access control
2222 only to the methods <code>POST</code>, <code>PUT</code>, and
2223 <code>DELETE</code>, leaving all other methods unprotected:</p>
2225 <pre class="prettyprint lang-config"><Limit POST PUT DELETE>
2227 </Limit></pre>
2230 <p>The method names listed can be one or more of: <code>GET</code>,
2231 <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
2232 <code>CONNECT</code>, <code>OPTIONS</code>,
2233 <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
2234 <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
2235 <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
2236 case-sensitive.</strong> If <code>GET</code> is used it will also
2237 restrict <code>HEAD</code> requests. The <code>TRACE</code> method
2238 cannot be limited (see <code class="directive"><a href="#traceenable">TraceEnable</a></code>).</p>
2240 <div class="warning">A <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section should always be
2241 used in preference to a <code class="directive"><Limit></code>
2242 section when restricting access, since a <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section provides protection
2243 against arbitrary methods.</div>
2245 <p>The <code class="directive"><Limit></code> and
2246 <code class="directive"><a href="#limitexcept"><LimitExcept></a></code>
2247 directives may be nested. In this case, each successive level of
2248 <code class="directive"><Limit></code> or <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> directives must
2249 further restrict the set of methods to which access controls apply.</p>
2251 <div class="warning">When using
2252 <code class="directive"><Limit></code> or
2253 <code class="directive"><LimitExcept></code> directives with
2254 the <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directive,
2255 note that the first <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code>
2256 to succeed authorizes the request, regardless of the presence of other
2257 <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directives.</div>
2259 <p>For example, given the following configuration, all users will
2260 be authorized for <code>POST</code> requests, and the
2261 <code>Require group editors</code> directive will be ignored
2264 <pre class="prettyprint lang-config"><LimitExcept GET>
2266 </LimitExcept>
2268 Require group editors
2269 </Limit></pre>
2273 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2274 <div class="directive-section"><h2><a name="LimitExcept" id="LimitExcept"><LimitExcept></a> <a name="limitexcept" id="limitexcept">Directive</a></h2>
2275 <table class="directive">
2276 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict access controls to all HTTP methods
2277 except the named ones</td></tr>
2278 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LimitExcept <var>method</var> [<var>method</var>] ... > ...
2279 </LimitExcept></code></td></tr>
2280 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
2281 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
2282 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2283 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2285 <p><code class="directive"><LimitExcept></code> and
2286 <code></LimitExcept></code> are used to enclose
2287 a group of access control directives which will then apply to any
2288 HTTP access method <strong>not</strong> listed in the arguments;
2289 i.e., it is the opposite of a <code class="directive"><a href="#limit"><Limit></a></code> section and can be used to control
2290 both standard and nonstandard/unrecognized methods. See the
2291 documentation for <code class="directive"><a href="#limit"><Limit></a></code> for more details.</p>
2295 <pre class="prettyprint lang-config"><LimitExcept POST GET>
2297 </LimitExcept></pre>
2302 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2303 <div class="directive-section"><h2><a name="LimitInternalRecursion" id="LimitInternalRecursion">LimitInternalRecursion</a> <a name="limitinternalrecursion" id="limitinternalrecursion">Directive</a></h2>
2304 <table class="directive">
2305 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine maximum number of internal redirects and nested
2306 subrequests</td></tr>
2307 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitInternalRecursion <var>number</var> [<var>number</var>]</code></td></tr>
2308 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitInternalRecursion 10</code></td></tr>
2309 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2310 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2311 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2313 <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
2314 redirects the original request to a CGI script. A subrequest is Apache httpd's
2315 mechanism to find out what would happen for some URI if it were requested.
2316 For example, <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> uses subrequests to look for the
2317 files listed in the <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
2320 <p><code class="directive">LimitInternalRecursion</code> prevents the server
2321 from crashing when entering an infinite loop of internal redirects or
2322 subrequests. Such loops are usually caused by misconfigurations.</p>
2324 <p>The directive stores two different limits, which are evaluated on
2325 per-request basis. The first <var>number</var> is the maximum number of
2326 internal redirects, that may follow each other. The second <var>number</var>
2327 determines, how deep subrequests may be nested. If you specify only one
2328 <var>number</var>, it will be assigned to both limits.</p>
2330 <pre class="prettyprint lang-config">LimitInternalRecursion 5</pre>
2334 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2335 <div class="directive-section"><h2><a name="LimitRequestBody" id="LimitRequestBody">LimitRequestBody</a> <a name="limitrequestbody" id="limitrequestbody">Directive</a></h2>
2336 <table class="directive">
2337 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restricts the total size of the HTTP request body sent
2338 from the client</td></tr>
2339 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestBody <var>bytes</var></code></td></tr>
2340 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestBody 0</code></td></tr>
2341 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2342 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2343 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2344 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2346 <p>This directive specifies the number of <var>bytes</var> from 0
2347 (meaning unlimited) to 2147483647 (2GB) that are allowed in a
2348 request body. See the note below for the limited applicability
2349 to proxy requests.</p>
2351 <p>The <code class="directive">LimitRequestBody</code> directive allows
2352 the user to set a limit on the allowed size of an HTTP request
2353 message body within the context in which the directive is given
2354 (server, per-directory, per-file or per-location). If the client
2355 request exceeds that limit, the server will return an error
2356 response instead of servicing the request. The size of a normal
2357 request message body will vary greatly depending on the nature of
2358 the resource and the methods allowed on that resource. CGI scripts
2359 typically use the message body for retrieving form information.
2360 Implementations of the <code>PUT</code> method will require
2361 a value at least as large as any representation that the server
2362 wishes to accept for that resource.</p>
2364 <p>This directive gives the server administrator greater
2365 control over abnormal client request behavior, which may be
2366 useful for avoiding some forms of denial-of-service
2369 <p>If, for example, you are permitting file upload to a particular
2370 location, and wish to limit the size of the uploaded file to 100K,
2371 you might use the following directive:</p>
2373 <pre class="prettyprint lang-config">LimitRequestBody 102400</pre>
2376 <div class="note"><p>For a full description of how this directive is interpreted by
2377 proxy requests, see the <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> documentation.</p>
2382 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2383 <div class="directive-section"><h2><a name="LimitRequestFields" id="LimitRequestFields">LimitRequestFields</a> <a name="limitrequestfields" id="limitrequestfields">Directive</a></h2>
2384 <table class="directive">
2385 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of HTTP request header fields that
2386 will be accepted from the client</td></tr>
2387 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFields <var>number</var></code></td></tr>
2388 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFields 100</code></td></tr>
2389 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2390 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2391 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2393 <p><var>Number</var> is an integer from 0 (meaning unlimited) to
2394 32767. The default value is defined by the compile-time
2395 constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
2398 <p>The <code class="directive">LimitRequestFields</code> directive allows
2399 the server administrator to modify the limit on the number of
2400 request header fields allowed in an HTTP request. A server needs
2401 this value to be larger than the number of fields that a normal
2402 client request might include. The number of request header fields
2403 used by a client rarely exceeds 20, but this may vary among
2404 different client implementations, often depending upon the extent
2405 to which a user has configured their browser to support detailed
2406 content negotiation. Optional HTTP extensions are often expressed
2407 using request header fields.</p>
2409 <p>This directive gives the server administrator greater
2410 control over abnormal client request behavior, which may be
2411 useful for avoiding some forms of denial-of-service attacks.
2412 The value should be increased if normal clients see an error
2413 response from the server that indicates too many fields were
2414 sent in the request.</p>
2418 <pre class="prettyprint lang-config">LimitRequestFields 50</pre>
2421 <div class="warning"><h3>Warning</h3>
2422 <p> When name-based virtual hosting is used, the value for this
2423 directive is taken from the default (first-listed) virtual host for the
2424 local IP and port combination.</p>
2429 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2430 <div class="directive-section"><h2><a name="LimitRequestFieldSize" id="LimitRequestFieldSize">LimitRequestFieldSize</a> <a name="limitrequestfieldsize" id="limitrequestfieldsize">Directive</a></h2>
2431 <table class="directive">
2432 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of the HTTP request header allowed from the
2434 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFieldSize <var>bytes</var></code></td></tr>
2435 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFieldSize 8190</code></td></tr>
2436 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2437 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2438 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2440 <p>This directive specifies the number of <var>bytes</var>
2441 that will be allowed in an HTTP request header.</p>
2443 <p>The <code class="directive">LimitRequestFieldSize</code> directive
2444 allows the server administrator to set the limit
2445 on the allowed size of an HTTP request header field. A server
2446 needs this value to be large enough to hold any one header field
2447 from a normal client request. The size of a normal request header
2448 field will vary greatly among different client implementations,
2449 often depending upon the extent to which a user has configured
2450 their browser to support detailed content negotiation. SPNEGO
2451 authentication headers can be up to 12392 bytes.</p>
2453 <p>This directive gives the server administrator greater
2454 control over abnormal client request behavior, which may be
2455 useful for avoiding some forms of denial-of-service attacks.</p>
2459 <pre class="prettyprint lang-config">LimitRequestFieldSize 4094</pre>
2462 <div class="note">Under normal conditions, the value should not be changed from
2465 <div class="warning"><h3>Warning</h3>
2466 <p> When name-based virtual hosting is used, the value for this
2467 directive is taken from the default (first-listed) virtual host best
2468 matching the current IP address and port combination.</p>
2472 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2473 <div class="directive-section"><h2><a name="LimitRequestLine" id="LimitRequestLine">LimitRequestLine</a> <a name="limitrequestline" id="limitrequestline">Directive</a></h2>
2474 <table class="directive">
2475 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limit the size of the HTTP request line that will be accepted
2476 from the client</td></tr>
2477 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestLine <var>bytes</var></code></td></tr>
2478 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestLine 8190</code></td></tr>
2479 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2480 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2481 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2483 <p>This directive sets the number of <var>bytes</var> that will be
2484 allowed on the HTTP request-line.</p>
2486 <p>The <code class="directive">LimitRequestLine</code> directive allows
2487 the server administrator to set the limit on the allowed size
2488 of a client's HTTP request-line. Since the request-line consists of the
2489 HTTP method, URI, and protocol version, the
2490 <code class="directive">LimitRequestLine</code> directive places a
2491 restriction on the length of a request-URI allowed for a request
2492 on the server. A server needs this value to be large enough to
2493 hold any of its resource names, including any information that
2494 might be passed in the query part of a <code>GET</code> request.</p>
2496 <p>This directive gives the server administrator greater
2497 control over abnormal client request behavior, which may be
2498 useful for avoiding some forms of denial-of-service attacks.</p>
2502 <pre class="prettyprint lang-config">LimitRequestLine 4094</pre>
2505 <div class="note">Under normal conditions, the value should not be changed from
2508 <div class="warning"><h3>Warning</h3>
2509 <p> When name-based virtual hosting is used, the value for this
2510 directive is taken from the default (first-listed) virtual host best
2511 matching the current IP address and port combination.</p>
2516 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2517 <div class="directive-section"><h2><a name="LimitXMLRequestBody" id="LimitXMLRequestBody">LimitXMLRequestBody</a> <a name="limitxmlrequestbody" id="limitxmlrequestbody">Directive</a></h2>
2518 <table class="directive">
2519 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of an XML-based request body</td></tr>
2520 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitXMLRequestBody <var>bytes</var></code></td></tr>
2521 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitXMLRequestBody 1000000</code></td></tr>
2522 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2523 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2524 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2525 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2527 <p>Limit (in bytes) on maximum size of an XML-based request
2528 body. A value of <code>0</code> will disable any checking.</p>
2532 <pre class="prettyprint lang-config">LimitXMLRequestBody 0</pre>
2537 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2538 <div class="directive-section"><h2><a name="Location" id="Location"><Location></a> <a name="location" id="location">Directive</a></h2>
2539 <table class="directive">
2540 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to matching
2542 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Location
2543 <var>URL-path</var>|<var>URL</var>> ... </Location></code></td></tr>
2544 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2545 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2546 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2548 <p>The <code class="directive"><Location></code> directive
2549 limits the scope of the enclosed directives by URL. It is similar to the
2550 <code class="directive"><a href="#directory"><Directory></a></code>
2551 directive, and starts a subsection which is terminated with a
2552 <code></Location></code> directive. <code class="directive"><Location></code> sections are processed in the
2553 order they appear in the configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
2554 <code>.htaccess</code> files are read, and after the <code class="directive"><a href="#files"><Files></a></code> sections.</p>
2556 <p><code class="directive"><Location></code> sections operate
2557 completely outside the filesystem. This has several consequences.
2558 Most importantly, <code class="directive"><Location></code>
2559 directives should not be used to control access to filesystem
2560 locations. Since several different URLs may map to the same
2561 filesystem location, such access controls may by circumvented.</p>
2563 <p>The enclosed directives will be applied to the request if the path component
2564 of the URL meets <em>any</em> of the following criteria:
2567 <li>The specified location matches exactly the path component of the URL.
2569 <li>The specified location, which ends in a forward slash, is a prefix
2570 of the path component of the URL (treated as a context root).
2572 <li>The specified location, with the addition of a trailing slash, is a
2573 prefix of the path component of the URL (also treated as a context root).
2577 In the example below, where no trailing slash is used, requests to
2578 /private1, /private1/ and /private1/file.txt will have the enclosed
2579 directives applied, but /private1other would not.
2581 <pre class="prettyprint lang-config"><Location /private1>
2583 </Location></pre>
2586 In the example below, where a trailing slash is used, requests to
2587 /private2/ and /private2/file.txt will have the enclosed
2588 directives applied, but /private2 and /private2other would not.
2590 <pre class="prettyprint lang-config"><Location /private2<em>/</em>>
2592 </Location></pre>
2595 <div class="note"><h3>When to use <code class="directive"><Location></code></h3>
2597 <p>Use <code class="directive"><Location></code> to apply
2598 directives to content that lives outside the filesystem. For
2599 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
2600 <code><Location /></code>, which is an easy way to
2601 apply a configuration to the entire server.</p>
2604 <p>For all origin (non-proxy) requests, the URL to be matched is a
2605 URL-path of the form <code>/path/</code>. <em>No scheme, hostname,
2606 port, or query string may be included.</em> For proxy requests, the
2607 URL to be matched is of the form
2608 <code>scheme://servername/path</code>, and you must include the
2611 <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
2612 any single character, and <code>*</code> matches any sequences of
2613 characters. Neither wildcard character matches a / in the URL-path.</p>
2615 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
2616 can also be used, with the addition of the <code>~</code>
2617 character. For example:</p>
2619 <pre class="prettyprint lang-config"><Location ~ "/(extra|special)/data">
2621 </Location></pre>
2624 <p>would match URLs that contained the substring <code>/extra/data</code>
2625 or <code>/special/data</code>. The directive <code class="directive"><a href="#locationmatch"><LocationMatch></a></code> behaves
2626 identical to the regex version of <code class="directive"><Location></code>, and is preferred, for the
2627 simple reason that <code>~</code> is hard to distinguish from
2628 <code>-</code> in many fonts.</p>
2630 <p>The <code class="directive"><Location></code>
2631 functionality is especially useful when combined with the
2632 <code class="directive"><a href="#sethandler">SetHandler</a></code>
2633 directive. For example, to enable status requests, but allow them
2634 only from browsers at <code>example.com</code>, you might use:</p>
2636 <pre class="prettyprint lang-config"><Location /status>
2637 SetHandler server-status
2638 Require host example.com
2639 </Location></pre>
2642 <div class="note"><h3>Note about / (slash)</h3>
2643 <p>The slash character has special meaning depending on where in a
2644 URL it appears. People may be used to its behavior in the filesystem
2645 where multiple adjacent slashes are frequently collapsed to a single
2646 slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
2647 <code>/home/foo</code>). In URL-space this is not necessarily true.
2648 The <code class="directive"><a href="#locationmatch"><LocationMatch></a></code>
2649 directive and the regex version of <code class="directive"><Location></code> require you to explicitly specify multiple
2650 slashes if that is your intention.</p>
2652 <p>For example, <code><LocationMatch ^/abc></code> would match
2653 the request URL <code>/abc</code> but not the request URL <code>
2654 //abc</code>. The (non-regex) <code class="directive"><Location></code> directive behaves similarly when used for
2655 proxy requests. But when (non-regex) <code class="directive"><Location></code> is used for non-proxy requests it will
2656 implicitly match multiple slashes with a single slash. For example,
2657 if you specify <code><Location /abc/def></code> and the
2658 request is to <code>/abc//def</code> then it will match.</p>
2663 <li><a href="../sections.html">How <Directory>, <Location>
2664 and <Files> sections work</a> for an explanation of how these
2665 different sections are combined when a request is received.</li>
2666 <li><code class="directive"><a href="#locationmatch">LocationMatch</a></code></li>
2669 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2670 <div class="directive-section"><h2><a name="LocationMatch" id="LocationMatch"><LocationMatch></a> <a name="locationmatch" id="locationmatch">Directive</a></h2>
2671 <table class="directive">
2672 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to regular-expression
2673 matching URLs</td></tr>
2674 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LocationMatch
2675 <var>regex</var>> ... </LocationMatch></code></td></tr>
2676 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2677 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2678 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2680 <p>The <code class="directive"><LocationMatch></code> directive
2681 limits the scope of the enclosed directives by URL, in an identical manner
2682 to <code class="directive"><a href="#location"><Location></a></code>. However,
2683 it takes a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
2684 as an argument instead of a simple string. For example:</p>
2686 <pre class="prettyprint lang-config"><LocationMatch "/(extra|special)/data">
2688 </LocationMatch></pre>
2691 <p>would match URLs that contained the substring <code>/extra/data</code>
2692 or <code>/special/data</code>.</p>
2694 <p>From 2.4.8 onwards, named groups and backreferences are captured and
2695 written to the environment with the corresponding name prefixed with
2696 "MATCH_" and in upper case. This allows elements of URLs to be referenced
2697 from within <a href="../expr.html">expressions</a> and modules like
2698 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
2699 (unnamed) backreferences are ignored. Use named groups instead.</p>
2701 <pre class="prettyprint lang-config"><LocationMatch ^/combined/(?<sitename>[^/]+)>
2702 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
2703 </LocationMatch></pre>
2708 <li><a href="../sections.html">How <Directory>, <Location>
2709 and <Files> sections work</a> for an explanation of how these
2710 different sections are combined when a request is received</li>
2713 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2714 <div class="directive-section"><h2><a name="LogLevel" id="LogLevel">LogLevel</a> <a name="loglevel" id="loglevel">Directive</a></h2>
2715 <table class="directive">
2716 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Controls the verbosity of the ErrorLog</td></tr>
2717 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel [<var>module</var>:]<var>level</var>
2718 [<var>module</var>:<var>level</var>] ...
2720 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LogLevel warn</code></td></tr>
2721 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2722 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2723 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2724 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Per-module and per-directory configuration is available in
2725 Apache HTTP Server 2.3.6 and later</td></tr>
2727 <p><code class="directive">LogLevel</code> adjusts the verbosity of the
2728 messages recorded in the error logs (see <code class="directive"><a href="#errorlog">ErrorLog</a></code> directive). The following
2729 <var>level</var>s are available, in order of decreasing
2732 <table class="bordered">
2735 <th><strong>Level</strong> </th>
2737 <th><strong>Description</strong> </th>
2739 <th><strong>Example</strong> </th>
2743 <td><code>emerg</code> </td>
2745 <td>Emergencies - system is unusable.</td>
2747 <td>"Child cannot open lock file. Exiting"</td>
2751 <td><code>alert</code> </td>
2753 <td>Action must be taken immediately.</td>
2755 <td>"getpwuid: couldn't determine user name from uid"</td>
2759 <td><code>crit</code> </td>
2761 <td>Critical Conditions.</td>
2763 <td>"socket: Failed to get a socket, exiting child"</td>
2767 <td><code>error</code> </td>
2769 <td>Error conditions.</td>
2771 <td>"Premature end of script headers"</td>
2775 <td><code>warn</code> </td>
2777 <td>Warning conditions.</td>
2779 <td>"child process 1234 did not exit, sending another
2784 <td><code>notice</code> </td>
2786 <td>Normal but significant condition.</td>
2788 <td>"httpd: caught SIGBUS, attempting to dump core in
2793 <td><code>info</code> </td>
2795 <td>Informational.</td>
2797 <td>"Server seems busy, (you may need to increase
2798 StartServers, or Min/MaxSpareServers)..."</td>
2802 <td><code>debug</code> </td>
2804 <td>Debug-level messages</td>
2806 <td>"Opening config file ..."</td>
2809 <td><code>trace1</code> </td>
2811 <td>Trace messages</td>
2813 <td>"proxy: FTP: control connection complete"</td>
2816 <td><code>trace2</code> </td>
2818 <td>Trace messages</td>
2820 <td>"proxy: CONNECT: sending the CONNECT request to the remote proxy"</td>
2823 <td><code>trace3</code> </td>
2825 <td>Trace messages</td>
2827 <td>"openssl: Handshake: start"</td>
2830 <td><code>trace4</code> </td>
2832 <td>Trace messages</td>
2834 <td>"read from buffered SSL brigade, mode 0, 17 bytes"</td>
2837 <td><code>trace5</code> </td>
2839 <td>Trace messages</td>
2841 <td>"map lookup FAILED: map=rewritemap key=keyname"</td>
2844 <td><code>trace6</code> </td>
2846 <td>Trace messages</td>
2848 <td>"cache lookup FAILED, forcing new map lookup"</td>
2851 <td><code>trace7</code> </td>
2853 <td>Trace messages, dumping large amounts of data</td>
2855 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2858 <td><code>trace8</code> </td>
2860 <td>Trace messages, dumping large amounts of data</td>
2862 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2866 <p>When a particular level is specified, messages from all
2867 other levels of higher significance will be reported as well.
2868 <em>E.g.</em>, when <code>LogLevel info</code> is specified,
2869 then messages with log levels of <code>notice</code> and
2870 <code>warn</code> will also be posted.</p>
2872 <p>Using a level of at least <code>crit</code> is
2877 <pre class="prettyprint lang-config">LogLevel notice</pre>
2880 <div class="note"><h3>Note</h3>
2881 <p>When logging to a regular file messages of the level
2882 <code>notice</code> cannot be suppressed and thus are always
2883 logged. However, this doesn't apply when logging is done
2884 using <code>syslog</code>.</p>
2887 <p>Specifying a level without a module name will reset the level
2888 for all modules to that level. Specifying a level with a module
2889 name will set the level for that module only. It is possible to
2890 use the module source file name, the module identifier, or the
2891 module identifier with the trailing <code>_module</code> omitted
2892 as module specification. This means the following three specifications
2895 <pre class="prettyprint lang-config">LogLevel info ssl:warn
2896 LogLevel info mod_ssl.c:warn
2897 LogLevel info ssl_module:warn</pre>
2900 <p>It is also possible to change the level per directory:</p>
2902 <pre class="prettyprint lang-config">LogLevel info
2903 <Directory "/usr/local/apache/htdocs/app">
2905 </Directory></pre>
2909 Per directory loglevel configuration only affects messages that are
2910 logged after the request has been parsed and that are associated with
2911 the request. Log messages which are associated with the connection or
2912 the server are not affected.
2917 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
2918 <li><code class="directive"><a href="#errorlogformat">ErrorLogFormat</a></code></li>
2919 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
2922 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2923 <div class="directive-section"><h2><a name="MaxKeepAliveRequests" id="MaxKeepAliveRequests">MaxKeepAliveRequests</a> <a name="maxkeepaliverequests" id="maxkeepaliverequests">Directive</a></h2>
2924 <table class="directive">
2925 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of requests allowed on a persistent
2926 connection</td></tr>
2927 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxKeepAliveRequests <var>number</var></code></td></tr>
2928 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxKeepAliveRequests 100</code></td></tr>
2929 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2930 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2931 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2933 <p>The <code class="directive">MaxKeepAliveRequests</code> directive
2934 limits the number of requests allowed per connection when
2935 <code class="directive"><a href="#keepalive">KeepAlive</a></code> is on. If it is
2936 set to <code>0</code>, unlimited requests will be allowed. We
2937 recommend that this setting be kept to a high value for maximum
2938 server performance.</p>
2942 <pre class="prettyprint lang-config">MaxKeepAliveRequests 500</pre>
2946 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2947 <div class="directive-section"><h2><a name="MaxRangeOverlaps" id="MaxRangeOverlaps">MaxRangeOverlaps</a> <a name="maxrangeoverlaps" id="maxrangeoverlaps">Directive</a></h2>
2948 <table class="directive">
2949 <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
2951 <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>
2952 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeOverlaps 20</code></td></tr>
2953 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2954 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2955 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2956 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
2958 <p>The <code class="directive">MaxRangeOverlaps</code> directive
2959 limits the number of overlapping HTTP ranges the server is willing to
2960 return to the client. If more overlapping ranges than permitted are requested,
2961 the complete resource is returned instead.</p>
2964 <dt><strong>default</strong></dt>
2965 <dd>Limits the number of overlapping ranges to a compile-time default of 20.</dd>
2967 <dt><strong>none</strong></dt>
2968 <dd>No overlapping Range headers are allowed.</dd>
2970 <dt><strong>unlimited</strong></dt>
2971 <dd>The server does not limit the number of overlapping ranges it is
2972 willing to satisfy.</dd>
2974 <dt><var>number-of-ranges</var></dt>
2975 <dd>A positive number representing the maximum number of overlapping ranges the
2976 server is willing to satisfy.</dd>
2980 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2981 <div class="directive-section"><h2><a name="MaxRangeReversals" id="MaxRangeReversals">MaxRangeReversals</a> <a name="maxrangereversals" id="maxrangereversals">Directive</a></h2>
2982 <table class="directive">
2983 <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
2985 <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>
2986 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRangeReversals 20</code></td></tr>
2987 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2988 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2989 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2990 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
2992 <p>The <code class="directive">MaxRangeReversals</code> directive
2993 limits the number of HTTP Range reversals the server is willing to
2994 return to the client. If more ranges reversals than permitted are requested,
2995 the complete resource is returned instead.</p>
2998 <dt><strong>default</strong></dt>
2999 <dd>Limits the number of range reversals to a compile-time default of 20.</dd>
3001 <dt><strong>none</strong></dt>
3002 <dd>No Range reversals headers are allowed.</dd>
3004 <dt><strong>unlimited</strong></dt>
3005 <dd>The server does not limit the number of range reversals it is
3006 willing to satisfy.</dd>
3008 <dt><var>number-of-ranges</var></dt>
3009 <dd>A positive number representing the maximum number of range reversals the
3010 server is willing to satisfy.</dd>
3014 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3015 <div class="directive-section"><h2><a name="MaxRanges" id="MaxRanges">MaxRanges</a> <a name="maxranges" id="maxranges">Directive</a></h2>
3016 <table class="directive">
3017 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of ranges allowed before returning the complete
3019 <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>
3020 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRanges 200</code></td></tr>
3021 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3022 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3023 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3024 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.15 and later</td></tr>
3026 <p>The <code class="directive">MaxRanges</code> directive
3027 limits the number of HTTP ranges the server is willing to
3028 return to the client. If more ranges than permitted are requested,
3029 the complete resource is returned instead.</p>
3032 <dt><strong>default</strong></dt>
3033 <dd>Limits the number of ranges to a compile-time default of 200.</dd>
3035 <dt><strong>none</strong></dt>
3036 <dd>Range headers are ignored.</dd>
3038 <dt><strong>unlimited</strong></dt>
3039 <dd>The server does not limit the number of ranges it is
3040 willing to satisfy.</dd>
3042 <dt><var>number-of-ranges</var></dt>
3043 <dd>A positive number representing the maximum number of ranges the
3044 server is willing to satisfy.</dd>
3048 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3049 <div class="directive-section"><h2><a name="MergeTrailers" id="MergeTrailers">MergeTrailers</a> <a name="mergetrailers" id="mergetrailers">Directive</a></h2>
3050 <table class="directive">
3051 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determins whether trailers are merged into headers</td></tr>
3052 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MergeTrailers [on|off]</code></td></tr>
3053 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MergeTrailers off</code></td></tr>
3054 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3055 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3056 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3057 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.4.10 and later</td></tr>
3059 <p>This directive controls whether HTTP trailers are copied into the
3060 internal representation of HTTP headers. This mergeing occurs when the
3061 request body has been completely consumed, long after most header
3062 processing would have a chance to examine or modify request headers.</p>
3063 <p>This option is provided for compatibility with releases prior to 2.4.10,
3064 where trailers were always merged.</p>
3067 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3068 <div class="directive-section"><h2><a name="Mutex" id="Mutex">Mutex</a> <a name="mutex" id="mutex">Directive</a></h2>
3069 <table class="directive">
3070 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures mutex mechanism and lock file directory for all
3071 or specified mutexes</td></tr>
3072 <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>
3073 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Mutex default</code></td></tr>
3074 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3075 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3076 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3077 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.4 and later</td></tr>
3079 <p>The <code class="directive">Mutex</code> directive sets the mechanism,
3080 and optionally the lock file location, that httpd and modules use
3081 to serialize access to resources. Specify <code>default</code> as
3082 the first argument to change the settings for all mutexes; specify
3083 a mutex name (see table below) as the first argument to override
3084 defaults only for that mutex.</p>
3086 <p>The <code class="directive">Mutex</code> directive is typically used in
3087 the following exceptional situations:</p>
3090 <li>change the mutex mechanism when the default mechanism selected
3091 by <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> has a functional or performance
3094 <li>change the directory used by file-based mutexes when the
3095 default directory does not support locking</li>
3098 <div class="note"><h3>Supported modules</h3>
3099 <p>This directive only configures mutexes which have been registered
3100 with the core server using the <code>ap_mutex_register()</code> API.
3101 All modules bundled with httpd support the <code class="directive">Mutex</code>
3102 directive, but third-party modules may not. Consult the documentation
3103 of the third-party module, which must indicate the mutex name(s) which
3104 can be configured if this directive is supported.</p>
3107 <p>The following mutex <em>mechanisms</em> are available:</p>
3109 <li><code>default | yes</code>
3110 <p>This selects the default locking implementation, as determined by
3111 <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a>. The default locking implementation can
3112 be displayed by running <code class="program"><a href="../programs/httpd.html">httpd</a></code> with the
3113 <code>-V</code> option.</p></li>
3115 <li><code>none | no</code>
3116 <p>This effectively disables the mutex, and is only allowed for a
3117 mutex if the module indicates that it is a valid choice. Consult the
3118 module documentation for more information.</p></li>
3120 <li><code>posixsem</code>
3121 <p>This is a mutex variant based on a Posix semaphore.</p>
3123 <div class="warning"><h3>Warning</h3>
3124 <p>The semaphore ownership is not recovered if a thread in the process
3125 holding the mutex segfaults, resulting in a hang of the web server.</p>
3129 <li><code>sysvsem</code>
3130 <p>This is a mutex variant based on a SystemV IPC semaphore.</p>
3132 <div class="warning"><h3>Warning</h3>
3133 <p>It is possible to "leak" SysV semaphores if processes crash
3134 before the semaphore is removed.</p>
3137 <div class="warning"><h3>Security</h3>
3138 <p>The semaphore API allows for a denial of service attack by any
3139 CGIs running under the same uid as the webserver (<em>i.e.</em>,
3140 all CGIs, unless you use something like <code class="program"><a href="../programs/suexec.html">suexec</a></code>
3141 or <code>cgiwrapper</code>).</p>
3145 <li><code>sem</code>
3146 <p>This selects the "best" available semaphore implementation, choosing
3147 between Posix and SystemV IPC semaphores, in that order.</p></li>
3149 <li><code>pthread</code>
3150 <p>This is a mutex variant based on cross-process Posix thread
3153 <div class="warning"><h3>Warning</h3>
3154 <p>On most systems, if a child process terminates abnormally while
3155 holding a mutex that uses this implementation, the server will deadlock
3156 and stop responding to requests. When this occurs, the server will
3157 require a manual restart to recover.</p>
3158 <p>Solaris is a notable exception as it provides a mechanism which
3159 usually allows the mutex to be recovered after a child process
3160 terminates abnormally while holding a mutex.</p>
3161 <p>If your system implements the
3162 <code>pthread_mutexattr_setrobust_np()</code> function, you may be able
3163 to use the <code>pthread</code> option safely.</p>
3167 <li><code>fcntl:/path/to/mutex</code>
3168 <p>This is a mutex variant where a physical (lock-)file and the
3169 <code>fcntl()</code> function are used as the mutex.</p>
3171 <div class="warning"><h3>Warning</h3>
3172 <p>When multiple mutexes based on this mechanism are used within
3173 multi-threaded, multi-process environments, deadlock errors (EDEADLK)
3174 can be reported for valid mutex operations if <code>fcntl()</code>
3175 is not thread-aware, such as on Solaris.</p>
3179 <li><code>flock:/path/to/mutex</code>
3180 <p>This is similar to the <code>fcntl:/path/to/mutex</code> method
3181 with the exception that the <code>flock()</code> function is used to
3182 provide file locking.</p></li>
3184 <li><code>file:/path/to/mutex</code>
3185 <p>This selects the "best" available file locking implementation,
3186 choosing between <code>fcntl</code> and <code>flock</code>, in that
3190 <p>Most mechanisms are only available on selected platforms, where the
3191 underlying platform and <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> support it. Mechanisms
3192 which aren't available on all platforms are <em>posixsem</em>,
3193 <em>sysvsem</em>, <em>sem</em>, <em>pthread</em>, <em>fcntl</em>,
3194 <em>flock</em>, and <em>file</em>.</p>
3196 <p>With the file-based mechanisms <em>fcntl</em> and <em>flock</em>,
3197 the path, if provided, is a directory where the lock file will be created.
3198 The default directory is httpd's run-time file directory relative to
3199 <code class="directive"><a href="#serverroot">ServerRoot</a></code>. Always use a local disk
3200 filesystem for <code>/path/to/mutex</code> and never a directory residing
3201 on a NFS- or AFS-filesystem. The basename of the file will be the mutex
3202 type, an optional instance string provided by the module, and unless the
3203 <code>OmitPID</code> keyword is specified, the process id of the httpd
3204 parent process will be appended to to make the file name unique, avoiding
3205 conflicts when multiple httpd instances share a lock file directory. For
3206 example, if the mutex name is <code>mpm-accept</code> and the lock file
3207 directory is <code>/var/httpd/locks</code>, the lock file name for the
3208 httpd instance with parent process id 12345 would be
3209 <code>/var/httpd/locks/mpm-accept.12345</code>.</p>
3211 <div class="warning"><h3>Security</h3>
3212 <p>It is best to <em>avoid</em> putting mutex files in a world-writable
3213 directory such as <code>/var/tmp</code> because someone could create
3214 a denial of service attack and prevent the server from starting by
3215 creating a lockfile with the same name as the one the server will try
3219 <p>The following table documents the names of mutexes used by httpd
3220 and bundled modules.</p>
3222 <table class="bordered"><tr class="header">
3225 <th>Protected resource</th>
3228 <td><code>mpm-accept</code></td>
3229 <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>
3230 <td>incoming connections, to avoid the thundering herd problem;
3231 for more information, refer to the
3232 <a href="../misc/perf-tuning.html">performance tuning</a>
3236 <td><code>authdigest-client</code></td>
3237 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3238 <td>client list in shared memory</td>
3241 <td><code>authdigest-opaque</code></td>
3242 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
3243 <td>counter in shared memory</td>
3246 <td><code>ldap-cache</code></td>
3247 <td><code class="module"><a href="../mod/mod_ldap.html">mod_ldap</a></code></td>
3248 <td>LDAP result cache</td>
3251 <td><code>rewrite-map</code></td>
3252 <td><code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code></td>
3253 <td>communication with external mapping programs, to avoid
3254 intermixed I/O from multiple requests</td>
3257 <td><code>ssl-cache</code></td>
3258 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3259 <td>SSL session cache</td>
3262 <td><code>ssl-stapling</code></td>
3263 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
3264 <td>OCSP stapling response cache</td>
3267 <td><code>watchdog-callback</code></td>
3268 <td><code class="module"><a href="../mod/mod_watchdog.html">mod_watchdog</a></code></td>
3269 <td>callback function of a particular client module</td>
3273 <p>The <code>OmitPID</code> keyword suppresses the addition of the httpd
3274 parent process id from the lock file name.</p>
3276 <p>In the following example, the mutex mechanism for the MPM accept
3277 mutex will be changed from the compiled-in default to <code>fcntl</code>,
3278 with the associated lock file created in directory
3279 <code>/var/httpd/locks</code>. The mutex mechanism for all other mutexes
3280 will be changed from the compiled-in default to <code>sysvsem</code>.</p>
3282 <pre class="prettyprint lang-config">Mutex sysvsem default
3283 Mutex fcntl:/var/httpd/locks mpm-accept</pre>
3287 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3288 <div class="directive-section"><h2><a name="NameVirtualHost" id="NameVirtualHost">NameVirtualHost</a> <a name="namevirtualhost" id="namevirtualhost">Directive</a></h2>
3289 <table class="directive">
3290 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>DEPRECATED: Designates an IP address for name-virtual
3292 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NameVirtualHost <var>addr</var>[:<var>port</var>]</code></td></tr>
3293 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3294 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3295 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3298 <p>Prior to 2.3.11, <code class="directive">NameVirtualHost</code> was required
3299 to instruct the server that a particular IP address and port combination
3300 was usable as a name-based virtual host. In 2.3.11 and later,
3301 any time an IP address and port combination is used in multiple virtual
3302 hosts, name-based virtual hosting is automatically enabled for that address.</p>
3304 <p>This directive currently has no effect.</p>
3308 <li><a href="../vhosts/">Virtual Hosts
3309 documentation</a></li>
3312 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3313 <div class="directive-section"><h2><a name="Options" id="Options">Options</a> <a name="options" id="options">Directive</a></h2>
3314 <table class="directive">
3315 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures what features are available in a particular
3317 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Options
3318 [+|-]<var>option</var> [[+|-]<var>option</var>] ...</code></td></tr>
3319 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Options FollowSymlinks</code></td></tr>
3320 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3321 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
3322 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3323 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3324 <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>
3326 <p>The <code class="directive">Options</code> directive controls which
3327 server features are available in a particular directory.</p>
3329 <p><var>option</var> can be set to <code>None</code>, in which
3330 case none of the extra features are enabled, or one or more of
3334 <dt><code>All</code></dt>
3336 <dd>All options except for <code>MultiViews</code>.</dd>
3338 <dt><code>ExecCGI</code></dt>
3341 Execution of CGI scripts using <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>
3344 <dt><code>FollowSymLinks</code></dt>
3347 The server will follow symbolic links in this directory. This is
3348 the default setting.
3350 <p>Even though the server follows the symlink it does <em>not</em>
3351 change the pathname used to match against <code class="directive"><a href="#directory"><Directory></a></code> sections.</p>
3353 <p>The <code>FollowSymLinks</code> and
3354 <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
3355 <code>.htaccess</code> files.</p>
3357 <p>Omitting this option should not be considered a security restriction,
3358 since symlink testing is subject to race conditions that make it
3362 <dt><code>Includes</code></dt>
3365 Server-side includes provided by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
3368 <dt><code>IncludesNOEXEC</code></dt>
3372 Server-side includes are permitted, but the <code>#exec
3373 cmd</code> and <code>#exec cgi</code> are disabled. It is still
3374 possible to <code>#include virtual</code> CGI scripts from
3375 <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>ed
3378 <dt><code>Indexes</code></dt>
3381 If a URL which maps to a directory is requested, and there
3382 is no <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
3383 (<em>e.g.</em>, <code>index.html</code>) in that directory, then
3384 <code class="module"><a href="../mod/mod_autoindex.html">mod_autoindex</a></code> will return a formatted listing
3385 of the directory.</dd>
3387 <dt><code>MultiViews</code></dt>
3390 <a href="../content-negotiation.html">Content negotiated</a>
3391 "MultiViews" are allowed using
3392 <code class="module"><a href="../mod/mod_negotiation.html">mod_negotiation</a></code>.
3393 <div class="note"><h3>Note</h3> <p>This option gets ignored if set
3394 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>
3395 needs real resources to compare against and evaluate from.</p></div>
3398 <dt><code>SymLinksIfOwnerMatch</code></dt>
3400 <dd>The server will only follow symbolic links for which the
3401 target file or directory is owned by the same user id as the
3404 <div class="note"><h3>Note</h3>
3405 <p>The <code>FollowSymLinks</code> and
3406 <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
3407 <code>.htaccess</code> files.</p>
3409 <p>This option should not be considered a security restriction,
3410 since symlink testing is subject to race conditions that make it
3415 <p>Normally, if multiple <code class="directive">Options</code> could
3416 apply to a directory, then the most specific one is used and
3417 others are ignored; the options are not merged. (See <a href="../sections.html#mergin">how sections are merged</a>.)
3418 However if <em>all</em> the options on the
3419 <code class="directive">Options</code> directive are preceded by a
3420 <code>+</code> or <code>-</code> symbol, the options are
3421 merged. Any options preceded by a <code>+</code> are added to the
3422 options currently in force, and any options preceded by a
3423 <code>-</code> are removed from the options currently in
3426 <div class="note"><h3>Note</h3>
3427 <p>Mixing <code class="directive">Options</code> with a <code>+</code> or
3428 <code>-</code> with those without is not valid syntax, and will be
3429 rejected during server startup by the syntax check with an abort.</p>
3432 <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>
3434 <pre class="prettyprint lang-config"><Directory "/web/docs">
3435 Options Indexes FollowSymLinks
3438 <Directory "/web/docs/spec">
3440 </Directory></pre>
3443 <p>then only <code>Includes</code> will be set for the
3444 <code>/web/docs/spec</code> directory. However if the second
3445 <code class="directive">Options</code> directive uses the <code>+</code> and
3446 <code>-</code> symbols:</p>
3448 <pre class="prettyprint lang-config"><Directory "/web/docs">
3449 Options Indexes FollowSymLinks
3452 <Directory "/web/docs/spec">
3453 Options +Includes -Indexes
3454 </Directory></pre>
3457 <p>then the options <code>FollowSymLinks</code> and
3458 <code>Includes</code> are set for the <code>/web/docs/spec</code>
3461 <div class="note"><h3>Note</h3>
3462 <p>Using <code>-IncludesNOEXEC</code> or
3463 <code>-Includes</code> disables server-side includes completely
3464 regardless of the previous setting.</p>
3467 <p>The default in the absence of any other settings is
3468 <code>FollowSymlinks</code>.</p>
3471 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3472 <div class="directive-section"><h2><a name="Protocol" id="Protocol">Protocol</a> <a name="protocol" id="protocol">Directive</a></h2>
3473 <table class="directive">
3474 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Protocol for a listening socket</td></tr>
3475 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Protocol <var>protocol</var></code></td></tr>
3476 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3477 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3478 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3479 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.1.5 and later.
3480 On Windows from Apache 2.3.3 and later.</td></tr>
3482 <p>This directive specifies the protocol used for a specific listening socket.
3483 The protocol is used to determine which module should handle a request, and
3484 to apply protocol specific optimizations with the <code class="directive">AcceptFilter</code>
3487 <p>You only need to set the protocol if you are running on non-standard ports, otherwise <code>http</code> is assumed for port 80 and <code>https</code> for port 443.</p>
3489 <p>For example, if you are running <code>https</code> on a non-standard port, specify the protocol explicitly:</p>
3491 <pre class="prettyprint lang-config">Protocol https</pre>
3494 <p>You can also specify the protocol using the <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code> directive.</p>
3498 <li><code class="directive"><a href="#acceptfilter">AcceptFilter</a></code></li>
3499 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
3502 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3503 <div class="directive-section"><h2><a name="RLimitCPU" id="RLimitCPU">RLimitCPU</a> <a name="rlimitcpu" id="rlimitcpu">Directive</a></h2>
3504 <table class="directive">
3505 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the CPU consumption of processes launched
3506 by Apache httpd children</td></tr>
3507 <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>
3508 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3509 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3510 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3511 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3512 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3514 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3515 resource limit for all processes and the second parameter sets
3516 the maximum resource limit. Either parameter can be a number,
3517 or <code>max</code> to indicate to the server that the limit should
3518 be set to the maximum allowed by the operating system
3519 configuration. Raising the maximum resource limit requires that
3520 the server is running as <code>root</code>, or in the initial startup
3523 <p>This applies to processes forked off from Apache httpd children
3524 servicing requests, not the Apache httpd children themselves. This
3525 includes CGI scripts and SSI exec commands, but not any
3526 processes forked off from the Apache httpd parent such as piped
3529 <p>CPU resource limits are expressed in seconds per
3534 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3535 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3538 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3539 <div class="directive-section"><h2><a name="RLimitMEM" id="RLimitMEM">RLimitMEM</a> <a name="rlimitmem" id="rlimitmem">Directive</a></h2>
3540 <table class="directive">
3541 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the memory consumption of processes launched
3542 by Apache httpd children</td></tr>
3543 <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>
3544 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3545 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3546 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3547 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3548 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3550 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3551 resource limit for all processes and the second parameter sets
3552 the maximum resource limit. Either parameter can be a number,
3553 or <code>max</code> to indicate to the server that the limit should
3554 be set to the maximum allowed by the operating system
3555 configuration. Raising the maximum resource limit requires that
3556 the server is running as <code>root</code>, or in the initial startup
3559 <p>This applies to processes forked off from Apache httpd children
3560 servicing requests, not the Apache httpd children themselves. This
3561 includes CGI scripts and SSI exec commands, but not any
3562 processes forked off from the Apache httpd parent such as piped
3565 <p>Memory resource limits are expressed in bytes per
3570 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3571 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3574 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3575 <div class="directive-section"><h2><a name="RLimitNPROC" id="RLimitNPROC">RLimitNPROC</a> <a name="rlimitnproc" id="rlimitnproc">Directive</a></h2>
3576 <table class="directive">
3577 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of processes that can be launched by
3578 processes launched by Apache httpd children</td></tr>
3579 <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>
3580 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3581 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3582 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3583 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3584 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3586 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3587 resource limit for all processes and the second parameter sets
3588 the maximum resource limit. Either parameter can be a number,
3589 or <code>max</code> to indicate to the server that the limit
3590 should be set to the maximum allowed by the operating system
3591 configuration. Raising the maximum resource limit requires that
3592 the server is running as <code>root</code>, or in the initial startup
3595 <p>This applies to processes forked off from Apache httpd children
3596 servicing requests, not the Apache httpd children themselves. This
3597 includes CGI scripts and SSI exec commands, but not any
3598 processes forked off from the Apache httpd parent such as piped
3601 <p>Process limits control the number of processes per user.</p>
3603 <div class="note"><h3>Note</h3>
3604 <p>If CGI processes are <strong>not</strong> running
3605 under user ids other than the web server user id, this directive
3606 will limit the number of processes that the server itself can
3607 create. Evidence of this situation will be indicated by
3608 <strong><code>cannot fork</code></strong> messages in the
3609 <code>error_log</code>.</p>
3614 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3615 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3618 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3619 <div class="directive-section"><h2><a name="ScriptInterpreterSource" id="ScriptInterpreterSource">ScriptInterpreterSource</a> <a name="scriptinterpretersource" id="scriptinterpretersource">Directive</a></h2>
3620 <table class="directive">
3621 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
3623 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ScriptInterpreterSource Registry|Registry-Strict|Script</code></td></tr>
3624 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ScriptInterpreterSource Script</code></td></tr>
3625 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3626 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3627 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3628 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3629 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Win32 only.</td></tr>
3631 <p>This directive is used to control how Apache httpd finds the
3632 interpreter used to run CGI scripts. The default setting is
3633 <code>Script</code>. This causes Apache httpd to use the interpreter pointed to
3634 by the shebang line (first line, starting with <code>#!</code>) in the
3635 script. On Win32 systems this line usually looks like:</p>
3637 <pre class="prettyprint lang-perl">#!C:/Perl/bin/perl.exe</pre>
3640 <p>or, if <code>perl</code> is in the <code>PATH</code>, simply:</p>
3642 <pre class="prettyprint lang-perl">#!perl</pre>
3645 <p>Setting <code>ScriptInterpreterSource Registry</code> will
3646 cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
3647 searched using the script file extension (e.g., <code>.pl</code>) as a
3648 search key. The command defined by the registry subkey
3649 <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
3650 <code>Shell\Open\Command</code> is used to open the script file. If the
3651 registry keys cannot be found, Apache httpd falls back to the behavior of the
3652 <code>Script</code> option.</p>
3654 <div class="warning"><h3>Security</h3>
3655 <p>Be careful when using <code>ScriptInterpreterSource
3656 Registry</code> with <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>'ed directories, because
3657 Apache httpd will try to execute <strong>every</strong> file within this
3658 directory. The <code>Registry</code> setting may cause undesired
3659 program calls on files which are typically not executed. For
3660 example, the default open command on <code>.htm</code> files on
3661 most Windows systems will execute Microsoft Internet Explorer, so
3662 any HTTP request for an <code>.htm</code> file existing within the
3663 script directory would start the browser in the background on the
3664 server. This is a good way to crash your system within a minute or
3668 <p>The option <code>Registry-Strict</code> which is new in Apache HTTP Server
3669 2.0 does the same thing as <code>Registry</code> but uses only the
3670 subkey <code>Shell\ExecCGI\Command</code>. The
3671 <code>ExecCGI</code> key is not a common one. It must be
3672 configured manually in the windows registry and hence prevents
3673 accidental program calls on your system.</p>
3676 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3677 <div class="directive-section"><h2><a name="SeeRequestTail" id="SeeRequestTail">SeeRequestTail</a> <a name="seerequesttail" id="seerequesttail">Directive</a></h2>
3678 <table class="directive">
3679 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine if mod_status displays the first 63 characters
3680 of a request or the last 63, assuming the request itself is greater than
3682 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SeeRequestTail On|Off</code></td></tr>
3683 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SeeRequestTail Off</code></td></tr>
3684 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3685 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3686 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3687 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.2.7 and later.</td></tr>
3689 <p>mod_status with <code>ExtendedStatus On</code>
3690 displays the actual request being handled.
3691 For historical purposes, only 63 characters of the request
3692 are actually stored for display purposes. This directive
3693 controls whether the 1st 63 characters are stored (the previous
3694 behavior and the default) or if the last 63 characters are. This
3695 is only applicable, of course, if the length of the request is
3696 64 characters or greater.</p>
3698 <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:
3701 <table class="bordered">
3703 <th>Off (default)</th>
3704 <td>GET /disk1/storage/apache/htdocs/images/imagestore1/food/apples</td>
3708 <td>orage/apache/htdocs/images/imagestore1/food/apples.jpg HTTP/1.1</td>
3714 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3715 <div class="directive-section"><h2><a name="ServerAdmin" id="ServerAdmin">ServerAdmin</a> <a name="serveradmin" id="serveradmin">Directive</a></h2>
3716 <table class="directive">
3717 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Email address that the server includes in error
3718 messages sent to the client</td></tr>
3719 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAdmin <var>email-address</var>|<var>URL</var></code></td></tr>
3720 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3721 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3722 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3724 <p>The <code class="directive">ServerAdmin</code> sets the contact address
3725 that the server includes in any error messages it returns to the
3726 client. If the <code>httpd</code> doesn't recognize the supplied argument
3728 assumes, that it's an <var>email-address</var> and prepends it with
3729 <code>mailto:</code> in hyperlink targets. However, it's recommended to
3730 actually use an email address, since there are a lot of CGI scripts that
3731 make that assumption. If you want to use an URL, it should point to another
3732 server under your control. Otherwise users may not be able to contact you in
3735 <p>It may be worth setting up a dedicated address for this, e.g.</p>
3737 <pre class="prettyprint lang-config">ServerAdmin www-admin@foo.example.com</pre>
3739 <p>as users do not always mention that they are talking about the
3743 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3744 <div class="directive-section"><h2><a name="ServerAlias" id="ServerAlias">ServerAlias</a> <a name="serveralias" id="serveralias">Directive</a></h2>
3745 <table class="directive">
3746 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Alternate names for a host used when matching requests
3747 to name-virtual hosts</td></tr>
3748 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</code></td></tr>
3749 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
3750 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3751 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3753 <p>The <code class="directive">ServerAlias</code> directive sets the
3754 alternate names for a host, for use with <a href="../vhosts/name-based.html">name-based virtual hosts</a>. The
3755 <code class="directive">ServerAlias</code> may include wildcards, if appropriate.</p>
3757 <pre class="prettyprint lang-config"><VirtualHost *:80>
3758 ServerName server.example.com
3759 ServerAlias server server2.example.com server2
3760 ServerAlias *.example.com
3761 UseCanonicalName Off
3763 </VirtualHost></pre>
3766 <p>Name-based virtual hosts for the best-matching set of <code class="directive"><a href="#virtualhost"><virtualhost></a></code>s are processed
3767 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
3768 (nor for ServerName vs. ServerAlias). </p>
3770 <p>The complete list of names in the <code class="directive">VirtualHost</code>
3771 directive are treated just like a (non wildcard)
3772 <code class="directive">ServerAlias</code>.</p>
3777 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3778 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
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="ServerName" id="ServerName">ServerName</a> <a name="servername" id="servername">Directive</a></h2>
3783 <table class="directive">
3784 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hostname and port that the server uses to identify
3786 <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>
3787 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3788 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3789 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3791 <p>The <code class="directive">ServerName</code> directive sets the
3792 request scheme, hostname and
3793 port that the server uses to identify itself. This is used when
3794 creating redirection URLs.</p>
3796 <p>Additionally, <code class="directive">ServerName</code> is used (possibly
3797 in conjunction with <code class="directive">ServerAlias</code>) to uniquely
3798 identify a virtual host, when using <a href="../vhosts/name-based.html">name-based virtual hosts</a>.</p>
3800 <p>For example, if the name of the
3801 machine hosting the web server is <code>simple.example.com</code>,
3802 but the machine also has the DNS alias <code>www.example.com</code>
3803 and you wish the web server to be so identified, the following
3804 directive should be used:</p>
3806 <pre class="prettyprint lang-config">ServerName www.example.com</pre>
3809 <p>The <code class="directive">ServerName</code> directive
3810 may appear anywhere within the definition of a server. However,
3811 each appearance overrides the previous appearance (within that
3814 <p>If no <code class="directive">ServerName</code> is specified, then the
3815 server attempts to deduce the client visible hostname by performing a
3816 reverse lookup on an IP address of the systems hostname.</p>
3818 <p>If no port is specified in the
3819 <code class="directive">ServerName</code>, then the server will use the
3820 port from the incoming request. For optimal reliability and
3821 predictability, you should specify an explicit hostname and port
3822 using the <code class="directive">ServerName</code> directive.</p>
3824 <p>If you are using <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
3825 the <code class="directive">ServerName</code> inside a
3826 <code class="directive"><a href="#virtualhost"><VirtualHost></a></code>
3827 section specifies what hostname must appear in the request's
3828 <code>Host:</code> header to match this virtual host.</p>
3830 <p>Sometimes, the server runs behind a device that processes SSL,
3831 such as a reverse proxy, load balancer or SSL offload
3832 appliance. When this is the case, specify the
3833 <code>https://</code> scheme and the port number to which the
3834 clients connect in the <code class="directive">ServerName</code> directive
3835 to make sure that the server generates the correct
3836 self-referential URLs.
3839 <p>See the description of the
3840 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> and
3841 <code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code> directives for
3842 settings which determine whether self-referential URLs (e.g., by the
3843 <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> module) will refer to the
3844 specified port, or to the port number given in the client's request.
3847 <div class="warning">
3848 <p>Failure to set <code class="directive">ServerName</code> to a name that
3849 your server can resolve to an IP address will result in a startup
3850 warning. <code>httpd</code> will then use whatever hostname it can
3851 determine, using the system's <code>hostname</code> command. This
3852 will almost never be the hostname you actually want.</p>
3853 <div class="example"><p><code>
3854 httpd: Could not reliably determine the server's fully qualified domain name, using rocinante.local for ServerName
3861 <li><a href="../dns-caveats.html">Issues Regarding DNS and
3862 Apache HTTP Server</a></li>
3863 <li><a href="../vhosts/">Apache HTTP Server virtual host
3864 documentation</a></li>
3865 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3866 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
3867 <li><code class="directive"><a href="#serveralias">ServerAlias</a></code></li>
3870 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3871 <div class="directive-section"><h2><a name="ServerPath" id="ServerPath">ServerPath</a> <a name="serverpath" id="serverpath">Directive</a></h2>
3872 <table class="directive">
3873 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Legacy URL pathname for a name-based virtual host that
3874 is accessed by an incompatible browser</td></tr>
3875 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerPath <var>URL-path</var></code></td></tr>
3876 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
3877 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3878 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3880 <p>The <code class="directive">ServerPath</code> directive sets the legacy
3881 URL pathname for a host, for use with <a href="../vhosts/">name-based virtual hosts</a>.</p>
3885 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
3888 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3889 <div class="directive-section"><h2><a name="ServerRoot" id="ServerRoot">ServerRoot</a> <a name="serverroot" id="serverroot">Directive</a></h2>
3890 <table class="directive">
3891 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server installation</td></tr>
3892 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerRoot <var>directory-path</var></code></td></tr>
3893 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerRoot /usr/local/apache</code></td></tr>
3894 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3895 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3896 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3898 <p>The <code class="directive">ServerRoot</code> directive sets the
3899 directory in which the server lives. Typically it will contain the
3900 subdirectories <code>conf/</code> and <code>logs/</code>. Relative
3901 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
3902 relative to this directory.</p>
3904 <pre class="prettyprint lang-config">ServerRoot "/home/httpd"</pre>
3907 <p>The default location of <code class="directive">ServerRoot</code> may be
3908 modified by using the <code>--prefix</code> argument to
3909 <a href="../programs/configure.html"><code>configure</code></a>, and
3910 most third-party distributions of the server have a different
3911 default location from the one listed above.</p>
3916 <li><a href="../invoking.html">the <code>-d</code>
3917 option to <code>httpd</code></a></li>
3918 <li><a href="../misc/security_tips.html#serverroot">the
3919 security tips</a> for information on how to properly set
3920 permissions on the <code class="directive">ServerRoot</code></li>
3923 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3924 <div class="directive-section"><h2><a name="ServerSignature" id="ServerSignature">ServerSignature</a> <a name="serversignature" id="serversignature">Directive</a></h2>
3925 <table class="directive">
3926 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the footer on server-generated documents</td></tr>
3927 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerSignature On|Off|EMail</code></td></tr>
3928 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerSignature Off</code></td></tr>
3929 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3930 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3931 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3932 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3934 <p>The <code class="directive">ServerSignature</code> directive allows the
3935 configuration of a trailing footer line under server-generated
3936 documents (error messages, <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> ftp directory
3937 listings, <code class="module"><a href="../mod/mod_info.html">mod_info</a></code> output, ...). The reason why you
3938 would want to enable such a footer line is that in a chain of proxies,
3939 the user often has no possibility to tell which of the chained servers
3940 actually produced a returned error message.</p>
3942 <p>The <code>Off</code>
3943 setting, which is the default, suppresses the footer line (and is
3944 therefore compatible with the behavior of Apache-1.2 and
3945 below). The <code>On</code> setting simply adds a line with the
3946 server version number and <code class="directive"><a href="#servername">ServerName</a></code> of the serving virtual host,
3947 and the <code>EMail</code> setting additionally creates a
3948 "mailto:" reference to the <code class="directive"><a href="#serveradmin">ServerAdmin</a></code> of the referenced
3951 <p>After version 2.0.44, the details of the server version number
3952 presented are controlled by the <code class="directive"><a href="#servertokens">ServerTokens</a></code> directive.</p>
3956 <li><code class="directive"><a href="#servertokens">ServerTokens</a></code></li>
3959 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3960 <div class="directive-section"><h2><a name="ServerTokens" id="ServerTokens">ServerTokens</a> <a name="servertokens" id="servertokens">Directive</a></h2>
3961 <table class="directive">
3962 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the <code>Server</code> HTTP response
3964 <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>
3965 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerTokens Full</code></td></tr>
3966 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3967 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3968 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3970 <p>This directive controls whether <code>Server</code> response
3971 header field which is sent back to clients includes a
3972 description of the generic OS-type of the server as well as
3973 information about compiled-in modules.</p>
3976 <dt><code>ServerTokens Full</code> (or not specified)</dt>
3978 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
3979 (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
3981 <dt><code>ServerTokens Prod[uctOnly]</code></dt>
3983 <dd>Server sends (<em>e.g.</em>): <code>Server:
3986 <dt><code>ServerTokens Major</code></dt>
3988 <dd>Server sends (<em>e.g.</em>): <code>Server:
3989 Apache/2</code></dd>
3991 <dt><code>ServerTokens Minor</code></dt>
3993 <dd>Server sends (<em>e.g.</em>): <code>Server:
3994 Apache/2.4</code></dd>
3996 <dt><code>ServerTokens Min[imal]</code></dt>
3998 <dd>Server sends (<em>e.g.</em>): <code>Server:
3999 Apache/2.4.2</code></dd>
4001 <dt><code>ServerTokens OS</code></dt>
4003 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.2
4008 <p>This setting applies to the entire server, and cannot be
4009 enabled or disabled on a virtualhost-by-virtualhost basis.</p>
4011 <p>After version 2.0.44, this directive also controls the
4012 information presented by the <code class="directive"><a href="#serversignature">ServerSignature</a></code> directive.</p>
4014 <div class="note">Setting <code class="directive">ServerTokens</code> to less than
4015 <code>minimal</code> is not recommended because it makes it more
4016 difficult to debug interoperational problems. Also note that
4017 disabling the Server: header does nothing at all to make your
4018 server more secure; the idea of "security through obscurity"
4019 is a myth and leads to a false sense of safety.</div>
4024 <li><code class="directive"><a href="#serversignature">ServerSignature</a></code></li>
4027 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4028 <div class="directive-section"><h2><a name="SetHandler" id="SetHandler">SetHandler</a> <a name="sethandler" id="sethandler">Directive</a></h2>
4029 <table class="directive">
4030 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be processed by a
4032 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetHandler <var>handler-name</var>|None</code></td></tr>
4033 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4034 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4035 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4036 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4038 <p>When placed into an <code>.htaccess</code> file or a
4039 <code class="directive"><a href="#directory"><Directory></a></code> or
4040 <code class="directive"><a href="#location"><Location></a></code>
4041 section, this directive forces all matching files to be parsed
4042 through the <a href="../handler.html">handler</a> given by
4043 <var>handler-name</var>. For example, if you had a directory you
4044 wanted to be parsed entirely as imagemap rule files, regardless
4045 of extension, you might put the following into an
4046 <code>.htaccess</code> file in that directory:</p>
4048 <pre class="prettyprint lang-config">SetHandler imap-file</pre>
4051 <p>Another example: if you wanted to have the server display a
4052 status report whenever a URL of
4053 <code>http://servername/status</code> was called, you might put
4054 the following into <code>httpd.conf</code>:</p>
4056 <pre class="prettyprint lang-config"><Location "/status">
4057 SetHandler server-status
4058 </Location></pre>
4061 <p>You could also use this directive to configure a particular
4062 handler for files with a particular file extension. For example:</p>
4064 <pre class="prettyprint lang-config"><FilesMatch \.php$>
4065 SetHandler application/x-httpd-php
4066 </FilesMatch></pre>
4069 <p>You can override an earlier defined <code class="directive">SetHandler</code>
4070 directive by using the value <code>None</code>.</p>
4072 <div class="note"><h3>Note</h3>
4073 <p>Because <code class="directive">SetHandler</code> overrides default handlers,
4074 normal behavior such as handling of URLs ending in a slash (/) as
4075 directories or index files is suppressed.</p></div>
4079 <li><code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code></li>
4082 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4083 <div class="directive-section"><h2><a name="SetInputFilter" id="SetInputFilter">SetInputFilter</a> <a name="setinputfilter" id="setinputfilter">Directive</a></h2>
4084 <table class="directive">
4085 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process client requests and POST
4087 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetInputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4088 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4089 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4090 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4091 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4093 <p>The <code class="directive">SetInputFilter</code> directive sets the
4094 filter or filters which will process client requests and POST
4095 input when they are received by the server. This is in addition to
4096 any filters defined elsewhere, including the
4097 <code class="directive"><a href="../mod/mod_mime.html#addinputfilter">AddInputFilter</a></code>
4100 <p>If more than one filter is specified, they must be separated
4101 by semicolons in the order in which they should process the
4106 <li><a href="../filter.html">Filters</a> documentation</li>
4109 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4110 <div class="directive-section"><h2><a name="SetOutputFilter" id="SetOutputFilter">SetOutputFilter</a> <a name="setoutputfilter" id="setoutputfilter">Directive</a></h2>
4111 <table class="directive">
4112 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process responses from the
4114 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
4115 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
4116 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
4117 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4118 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4120 <p>The <code class="directive">SetOutputFilter</code> directive sets the filters
4121 which will process responses from the server before they are
4122 sent to the client. This is in addition to any filters defined
4123 elsewhere, including the
4124 <code class="directive"><a href="../mod/mod_mime.html#addoutputfilter">AddOutputFilter</a></code>
4127 <p>For example, the following configuration will process all files
4128 in the <code>/www/data/</code> directory for server-side
4131 <pre class="prettyprint lang-config"><Directory "/www/data/">
4132 SetOutputFilter INCLUDES
4133 </Directory></pre>
4136 <p>If more than one filter is specified, they must be separated
4137 by semicolons in the order in which they should process the
4142 <li><a href="../filter.html">Filters</a> documentation</li>
4145 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4146 <div class="directive-section"><h2><a name="TimeOut" id="TimeOut">TimeOut</a> <a name="timeout" id="timeout">Directive</a></h2>
4147 <table class="directive">
4148 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for
4149 certain events before failing a request</td></tr>
4150 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TimeOut <var>seconds</var></code></td></tr>
4151 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TimeOut 60</code></td></tr>
4152 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4153 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4154 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4156 <p>The <code class="directive">TimeOut</code> directive defines the length
4157 of time Apache httpd will wait for I/O in various circumstances:</p>
4160 <li>When reading data from the client, the length of time to
4161 wait for a TCP packet to arrive if the read buffer is
4164 <li>When writing data to the client, the length of time to wait
4165 for an acknowledgement of a packet if the send buffer is
4168 <li>In <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>, the length of time to wait for
4169 output from a CGI script.</li>
4171 <li>In <code class="module"><a href="../mod/mod_ext_filter.html">mod_ext_filter</a></code>, the length of time to
4172 wait for output from a filtering process.</li>
4174 <li>In <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>, the default timeout value if
4175 <code class="directive"><a href="../mod/mod_proxy.html#proxytimeout">ProxyTimeout</a></code> is not
4181 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4182 <div class="directive-section"><h2><a name="TraceEnable" id="TraceEnable">TraceEnable</a> <a name="traceenable" id="traceenable">Directive</a></h2>
4183 <table class="directive">
4184 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines the behavior on <code>TRACE</code> requests</td></tr>
4185 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TraceEnable <var>[on|off|extended]</var></code></td></tr>
4186 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TraceEnable on</code></td></tr>
4187 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
4188 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4189 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4191 <p>This directive overrides the behavior of <code>TRACE</code> for both
4192 the core server and <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>. The default
4193 <code>TraceEnable on</code> permits <code>TRACE</code> requests per
4194 RFC 2616, which disallows any request body to accompany the request.
4195 <code>TraceEnable off</code> causes the core server and
4196 <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> to return a <code>405</code> (Method not
4197 allowed) error to the client.</p>
4199 <p>Finally, for testing and diagnostic purposes only, request
4200 bodies may be allowed using the non-compliant <code>TraceEnable
4201 extended</code> directive. The core (as an origin server) will
4202 restrict the request body to 64k (plus 8k for chunk headers if
4203 <code>Transfer-Encoding: chunked</code> is used). The core will
4204 reflect the full headers and all chunk headers with the response
4205 body. As a proxy server, the request body is not restricted to 64k.</p>
4207 <div class="note"><h3>Note</h3>
4208 <p>Despite claims to the contrary, <code>TRACE</code> is not
4209 a security vulnerability and there is no viable reason for
4210 it to be disabled. Doing so necessarily makes your server
4215 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4216 <div class="directive-section"><h2><a name="UnDefine" id="UnDefine">UnDefine</a> <a name="undefine" id="undefine">Directive</a></h2>
4217 <table class="directive">
4218 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Undefine the existence of a variable</td></tr>
4219 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UnDefine <var>parameter-name</var></code></td></tr>
4220 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4221 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4222 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4224 <p>Undoes the effect of a <code class="directive"><a href="#define">Define</a></code> or
4225 of passing a <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</p>
4226 <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
4227 <code>-D</code> arguments in any startup scripts.</p>
4230 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4231 <div class="directive-section"><h2><a name="UseCanonicalName" id="UseCanonicalName">UseCanonicalName</a> <a name="usecanonicalname" id="usecanonicalname">Directive</a></h2>
4232 <table class="directive">
4233 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own name and
4235 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalName On|Off|DNS</code></td></tr>
4236 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalName Off</code></td></tr>
4237 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4238 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4239 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4241 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4242 URL -- that is, a URL that refers back to the same server. With
4243 <code>UseCanonicalName On</code> Apache httpd will use the hostname and port
4244 specified in the <code class="directive"><a href="#servername">ServerName</a></code>
4245 directive to construct the canonical name for the server. This name
4246 is used in all self-referential URLs, and for the values of
4247 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>
4249 <p>With <code>UseCanonicalName Off</code> Apache httpd will form
4250 self-referential URLs using the hostname and port supplied by
4251 the client if any are supplied (otherwise it will use the
4252 canonical name, as defined above). These values are the same
4253 that are used to implement <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
4254 and are available with the same clients. The CGI variables
4255 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
4256 constructed from the client supplied values as well.</p>
4258 <p>An example where this may be useful is on an intranet server
4259 where you have users connecting to the machine using short
4260 names such as <code>www</code>. You'll notice that if the users
4261 type a shortname, and a URL which is a directory, such as
4262 <code>http://www/splat</code>, <em>without the trailing
4263 slash</em> then Apache httpd will redirect them to
4264 <code>http://www.example.com/splat/</code>. If you have
4265 authentication enabled, this will cause the user to have to
4266 authenticate twice (once for <code>www</code> and once again
4267 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">
4268 the FAQ on this subject for more information</a>). But if
4269 <code class="directive">UseCanonicalName</code> is set <code>Off</code>, then
4270 Apache httpd will redirect to <code>http://www/splat/</code>.</p>
4272 <p>There is a third option, <code>UseCanonicalName DNS</code>,
4273 which is intended for use with mass IP-based virtual hosting to
4274 support ancient clients that do not provide a
4275 <code>Host:</code> header. With this option Apache httpd does a
4276 reverse DNS lookup on the server IP address that the client
4277 connected to in order to work out self-referential URLs.</p>
4279 <div class="warning"><h3>Warning</h3>
4280 <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>
4281 they may be broken by this option. The client is essentially free
4282 to give whatever value they want as a hostname. But if the CGI is
4283 only using <code>SERVER_NAME</code> to construct self-referential URLs
4284 then it should be just fine.</p>
4289 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
4290 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4291 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4294 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4295 <div class="directive-section"><h2><a name="UseCanonicalPhysicalPort" id="UseCanonicalPhysicalPort">UseCanonicalPhysicalPort</a> <a name="usecanonicalphysicalport" id="usecanonicalphysicalport">Directive</a></h2>
4296 <table class="directive">
4297 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own port</td></tr>
4298 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalPhysicalPort On|Off</code></td></tr>
4299 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalPhysicalPort Off</code></td></tr>
4300 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
4301 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4302 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4304 <p>In many situations Apache httpd must construct a <em>self-referential</em>
4305 URL -- that is, a URL that refers back to the same server. With
4306 <code>UseCanonicalPhysicalPort On</code> Apache httpd will, when
4307 constructing the canonical port for the server to honor
4308 the <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> directive,
4309 provide the actual physical port number being used by this request
4310 as a potential port. With <code>UseCanonicalPhysicalPort Off</code>
4311 Apache httpd will not ever use the actual physical port number, instead
4312 relying on all configured information to construct a valid port number.</p>
4314 <div class="note"><h3>Note</h3>
4315 <p>The ordering of the lookup when the physical port is used is as
4318 <dt><code>UseCanonicalName On</code></dt>
4321 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4322 <li>Physical port</li>
4323 <li>Default port</li>
4326 <dt><code>UseCanonicalName Off | DNS</code></dt>
4329 <li>Parsed port from <code>Host:</code> header</li>
4330 <li>Physical port</li>
4331 <li>Port provided in <code class="directive"><a href="#servername">Servername</a></code></li>
4332 <li>Default port</li>
4337 <p>With <code>UseCanonicalPhysicalPort Off</code>, the
4338 physical ports are removed from the ordering.</p>
4344 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
4345 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
4346 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
4349 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
4350 <div class="directive-section"><h2><a name="VirtualHost" id="VirtualHost"><VirtualHost></a> <a name="virtualhost" id="virtualhost">Directive</a></h2>
4351 <table class="directive">
4352 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only to a specific
4353 hostname or IP address</td></tr>
4354 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><VirtualHost
4355 <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
4356 ...> ... </VirtualHost></code></td></tr>
4357 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
4358 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
4359 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
4361 <p><code class="directive"><VirtualHost></code> and
4362 <code></VirtualHost></code> are used to enclose a group of
4363 directives that will apply only to a particular virtual host. Any
4364 directive that is allowed in a virtual host context may be
4365 used. When the server receives a request for a document on a
4366 particular virtual host, it uses the configuration directives
4367 enclosed in the <code class="directive"><VirtualHost></code>
4368 section. <var>Addr</var> can be any of the following, optionally followed by
4369 a colon and a port number (or *):</p>
4372 <li>The IP address of the virtual host;</li>
4374 <li>A fully qualified domain name for the IP address of the
4375 virtual host (not recommended);</li>
4377 <li>The character <code>*</code>, which acts as a wildcard and matches
4378 any IP address.</li>
4380 <li>The string <code>_default_</code>, which is an alias for <code>*</code></li>
4384 <pre class="prettyprint lang-config"><VirtualHost 10.1.2.3:80>
4385 ServerAdmin webmaster@host.example.com
4386 DocumentRoot /www/docs/host.example.com
4387 ServerName host.example.com
4388 ErrorLog logs/host.example.com-error_log
4389 TransferLog logs/host.example.com-access_log
4390 </VirtualHost></pre>
4394 <p>IPv6 addresses must be specified in square brackets because
4395 the optional port number could not be determined otherwise. An
4396 IPv6 example is shown below:</p>
4398 <pre class="prettyprint lang-config"><VirtualHost [2001:db8::a00:20ff:fea7:ccea]:80>
4399 ServerAdmin webmaster@host.example.com
4400 DocumentRoot /www/docs/host.example.com
4401 ServerName host.example.com
4402 ErrorLog logs/host.example.com-error_log
4403 TransferLog logs/host.example.com-access_log
4404 </VirtualHost></pre>
4407 <p>Each Virtual Host must correspond to a different IP address,
4408 different port number or a different host name for the server,
4409 in the former case the server machine must be configured to
4410 accept IP packets for multiple addresses. (If the machine does
4411 not have multiple network interfaces, then this can be
4412 accomplished with the <code>ifconfig alias</code> command -- if
4413 your OS supports it).</p>
4415 <div class="note"><h3>Note</h3>
4416 <p>The use of <code class="directive"><VirtualHost></code> does
4417 <strong>not</strong> affect what addresses Apache httpd listens on. You
4418 may need to ensure that Apache httpd is listening on the correct addresses
4419 using <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>.</p>
4422 <p>A <code class="directive"><a href="#servername">ServerName</a></code> should be
4423 specified inside each <code class="directive"><VirtualHost></code> block. If it is absent, the
4424 <code class="directive"><a href="#servername">ServerName</a></code> from the "main"
4425 server configuration will be inherited.</p>
4427 <p>When a request is received, the server first maps it to the best matching
4428 <code class="directive"><VirtualHost></code> based on the local
4429 IP address and port combination only. Non-wildcards have a higher
4430 precedence. If no match based on IP and port occurs at all, the
4431 "main" server configuration is used.</p>
4433 <p>If multiple virtual hosts contain the best matching IP address and port,
4434 the server selects from these virtual hosts the best match based on the
4435 requested hostname. If no matching name-based virtual host is found,
4436 then the first listed virtual host that matched the IP address will be
4437 used. As a consequence, the first listed virtual host for a given IP address
4438 and port combination is default virtual host for that IP and port
4441 <div class="warning"><h3>Security</h3>
4442 <p>See the <a href="../misc/security_tips.html">security tips</a>
4443 document for details on why your security could be compromised if the
4444 directory where log files are stored is writable by anyone other
4445 than the user that starts the server.</p>
4450 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
4451 <li><a href="../dns-caveats.html">Issues Regarding DNS and
4452 Apache HTTP Server</a></li>
4453 <li><a href="../bind.html">Setting
4454 which addresses and ports Apache HTTP Server uses</a></li>
4455 <li><a href="../sections.html">How <Directory>, <Location>
4456 and <Files> sections work</a> for an explanation of how these
4457 different sections are combined when a request is received</li>
4461 <div class="bottomlang">
4462 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
4463 <a href="../en/mod/core.html" title="English"> en </a> |
4464 <a href="../es/mod/core.html" hreflang="es" rel="alternate" title="Español"> es </a> |
4465 <a href="../fr/mod/core.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
4466 <a href="../ja/mod/core.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
4467 <a href="../tr/mod/core.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p>
4468 </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>
4469 <script type="text/javascript"><!--//--><![CDATA[//><!--
4470 var comments_shortname = 'httpd';
4471 var comments_identifier = 'http://httpd.apache.org/docs/2.4/mod/core.html';
4473 if (w.location.hostname.toLowerCase() == "httpd.apache.org") {
4474 d.write('<div id="comments_thread"><\/div>');
4475 var s = d.createElement('script');
4476 s.type = 'text/javascript';
4478 s.src = 'https://comments.apache.org/show_comments.lua?site=' + comments_shortname + '&page=' + comments_identifier;
4479 (d.getElementsByTagName('head')[0] || d.getElementsByTagName('body')[0]).appendChild(s);
4482 d.write('<div id="comments_thread">Comments are disabled for this page at the moment.<\/div>');
4484 })(window, document);
4485 //--><!]]></script></div><div id="footer">
4486 <p class="apache">Copyright 2015 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p>
4487 <p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div><script type="text/javascript"><!--//--><
projects / apache / blob