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8 <title>core - Apache HTTP Server</title>
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15 <p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p>
16 <p class="apache">Apache HTTP Server Version 2.3</p>
17 <img alt="" src="../images/feather.gif" /></div>
18 <div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div>
20 <a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.3</a> > <a href="./">Modules</a></div>
21 <div id="page-content">
22 <div id="preamble"><h1>Apache Core Features</h1>
24 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
25 <a href="../en/mod/core.html" title="English"> en </a> |
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27 <a href="../ja/mod/core.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
28 <a href="../tr/mod/core.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p>
30 <table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Core Apache HTTP Server features that are always
32 <tr><th><a href="module-dict.html#Status">Status:</a></th><td>Core</td></tr></table>
34 <div id="quickview"><h3 class="directives">Directives</h3>
36 <li><img alt="" src="../images/down.gif" /> <a href="#acceptfilter">AcceptFilter</a></li>
37 <li><img alt="" src="../images/down.gif" /> <a href="#acceptpathinfo">AcceptPathInfo</a></li>
38 <li><img alt="" src="../images/down.gif" /> <a href="#accessfilename">AccessFileName</a></li>
39 <li><img alt="" src="../images/down.gif" /> <a href="#adddefaultcharset">AddDefaultCharset</a></li>
40 <li><img alt="" src="../images/down.gif" /> <a href="#allowencodedslashes">AllowEncodedSlashes</a></li>
41 <li><img alt="" src="../images/down.gif" /> <a href="#allowoverride">AllowOverride</a></li>
42 <li><img alt="" src="../images/down.gif" /> <a href="#cgimapextension">CGIMapExtension</a></li>
43 <li><img alt="" src="../images/down.gif" /> <a href="#contentdigest">ContentDigest</a></li>
44 <li><img alt="" src="../images/down.gif" /> <a href="#defaulttype">DefaultType</a></li>
45 <li><img alt="" src="../images/down.gif" /> <a href="#define">Define</a></li>
46 <li><img alt="" src="../images/down.gif" /> <a href="#directory"><Directory></a></li>
47 <li><img alt="" src="../images/down.gif" /> <a href="#directorymatch"><DirectoryMatch></a></li>
48 <li><img alt="" src="../images/down.gif" /> <a href="#documentroot">DocumentRoot</a></li>
49 <li><img alt="" src="../images/down.gif" /> <a href="#enablemmap">EnableMMAP</a></li>
50 <li><img alt="" src="../images/down.gif" /> <a href="#enablesendfile">EnableSendfile</a></li>
51 <li><img alt="" src="../images/down.gif" /> <a href="#errordocument">ErrorDocument</a></li>
52 <li><img alt="" src="../images/down.gif" /> <a href="#errorlog">ErrorLog</a></li>
53 <li><img alt="" src="../images/down.gif" /> <a href="#errorlogformat">ErrorLogFormat</a></li>
54 <li><img alt="" src="../images/down.gif" /> <a href="#extendedstatus">ExtendedStatus</a></li>
55 <li><img alt="" src="../images/down.gif" /> <a href="#fileetag">FileETag</a></li>
56 <li><img alt="" src="../images/down.gif" /> <a href="#files"><Files></a></li>
57 <li><img alt="" src="../images/down.gif" /> <a href="#filesmatch"><FilesMatch></a></li>
58 <li><img alt="" src="../images/down.gif" /> <a href="#forcetype">ForceType</a></li>
59 <li><img alt="" src="../images/down.gif" /> <a href="#hostnamelookups">HostnameLookups</a></li>
60 <li><img alt="" src="../images/down.gif" /> <a href="#if"><If></a></li>
61 <li><img alt="" src="../images/down.gif" /> <a href="#ifdefine"><IfDefine></a></li>
62 <li><img alt="" src="../images/down.gif" /> <a href="#ifmodule"><IfModule></a></li>
63 <li><img alt="" src="../images/down.gif" /> <a href="#include">Include</a></li>
64 <li><img alt="" src="../images/down.gif" /> <a href="#keepalive">KeepAlive</a></li>
65 <li><img alt="" src="../images/down.gif" /> <a href="#keepalivetimeout">KeepAliveTimeout</a></li>
66 <li><img alt="" src="../images/down.gif" /> <a href="#limit"><Limit></a></li>
67 <li><img alt="" src="../images/down.gif" /> <a href="#limitexcept"><LimitExcept></a></li>
68 <li><img alt="" src="../images/down.gif" /> <a href="#limitinternalrecursion">LimitInternalRecursion</a></li>
69 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestbody">LimitRequestBody</a></li>
70 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfields">LimitRequestFields</a></li>
71 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfieldsize">LimitRequestFieldSize</a></li>
72 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestline">LimitRequestLine</a></li>
73 <li><img alt="" src="../images/down.gif" /> <a href="#limitxmlrequestbody">LimitXMLRequestBody</a></li>
74 <li><img alt="" src="../images/down.gif" /> <a href="#location"><Location></a></li>
75 <li><img alt="" src="../images/down.gif" /> <a href="#locationmatch"><LocationMatch></a></li>
76 <li><img alt="" src="../images/down.gif" /> <a href="#loglevel">LogLevel</a></li>
77 <li><img alt="" src="../images/down.gif" /> <a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></li>
78 <li><img alt="" src="../images/down.gif" /> <a href="#mutex">Mutex</a></li>
79 <li><img alt="" src="../images/down.gif" /> <a href="#namevirtualhost">NameVirtualHost</a></li>
80 <li><img alt="" src="../images/down.gif" /> <a href="#options">Options</a></li>
81 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitcpu">RLimitCPU</a></li>
82 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitmem">RLimitMEM</a></li>
83 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitnproc">RLimitNPROC</a></li>
84 <li><img alt="" src="../images/down.gif" /> <a href="#scriptinterpretersource">ScriptInterpreterSource</a></li>
85 <li><img alt="" src="../images/down.gif" /> <a href="#seerequesttail">SeeRequestTail</a></li>
86 <li><img alt="" src="../images/down.gif" /> <a href="#serveradmin">ServerAdmin</a></li>
87 <li><img alt="" src="../images/down.gif" /> <a href="#serveralias">ServerAlias</a></li>
88 <li><img alt="" src="../images/down.gif" /> <a href="#servername">ServerName</a></li>
89 <li><img alt="" src="../images/down.gif" /> <a href="#serverpath">ServerPath</a></li>
90 <li><img alt="" src="../images/down.gif" /> <a href="#serverroot">ServerRoot</a></li>
91 <li><img alt="" src="../images/down.gif" /> <a href="#serversignature">ServerSignature</a></li>
92 <li><img alt="" src="../images/down.gif" /> <a href="#servertokens">ServerTokens</a></li>
93 <li><img alt="" src="../images/down.gif" /> <a href="#sethandler">SetHandler</a></li>
94 <li><img alt="" src="../images/down.gif" /> <a href="#setinputfilter">SetInputFilter</a></li>
95 <li><img alt="" src="../images/down.gif" /> <a href="#setoutputfilter">SetOutputFilter</a></li>
96 <li><img alt="" src="../images/down.gif" /> <a href="#timeout">TimeOut</a></li>
97 <li><img alt="" src="../images/down.gif" /> <a href="#traceenable">TraceEnable</a></li>
98 <li><img alt="" src="../images/down.gif" /> <a href="#undefine">UnDefine</a></li>
99 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalname">UseCanonicalName</a></li>
100 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></li>
101 <li><img alt="" src="../images/down.gif" /> <a href="#virtualhost"><VirtualHost></a></li>
105 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
106 <div class="directive-section"><h2><a name="AcceptFilter" id="AcceptFilter">AcceptFilter</a> <a name="acceptfilter" id="acceptfilter">Directive</a></h2>
107 <table class="directive">
108 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures optimizations for a Protocol's Listener Sockets</td></tr>
109 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptFilter <var>protocol</var> <var>accept_filter</var></code></td></tr>
110 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
111 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
112 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
113 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.1.5 and later.
114 On Windows from Apache httpd 2.3.3 and later.</td></tr>
116 <p>This directive enables operating system specific optimizations for a
117 listening socket by the Protocol type. The basic premise is for the
118 kernel to not send a socket to the server process until either data
119 is received or an entire HTTP Request is buffered. Only
120 <a href="http://www.freebsd.org/cgi/man.cgi?query=accept_filter&sektion=9">
121 FreeBSD's Accept Filters</a>, Linux's more primitive
122 <code>TCP_DEFER_ACCEPT</code>, and Windows' optimized AcceptEx()
123 are currently supported.</p>
125 <p>Using <code>none</code> for an argument will disable any accept filters
126 for that protocol. This is useful for protocols that require a server
127 send data first, such as <code>ftp:</code> or <code>nntp</code>:</p>
128 <div class="example"><p><code>AcceptFilter nntp none</code></p></div>
130 <p>The default values on FreeBSD are:</p>
131 <div class="example"><p><code>
132 AcceptFilter http httpready <br />
133 AcceptFilter https dataready
136 <p>The <code>httpready</code> accept filter buffers entire HTTP requests at
137 the kernel level. Once an entire request is received, the kernel then
138 sends it to the server. See the
139 <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_http&sektion=9">
140 accf_http(9)</a> man page for more details. Since HTTPS requests are
141 encrypted only the <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_data&sektion=9">
142 accf_data(9)</a> filter is used.</p>
144 <p>The default values on Linux are:</p>
145 <div class="example"><p><code>
146 AcceptFilter http data <br />
147 AcceptFilter https data
150 <p>Linux's <code>TCP_DEFER_ACCEPT</code> does not support buffering http
151 requests. Any value besides <code>none</code> will enable
152 <code>TCP_DEFER_ACCEPT</code> on that listener. For more details
154 <a href="http://homepages.cwi.nl/~aeb/linux/man2html/man7/tcp.7.html">
155 tcp(7)</a> man page.</p>
157 <p>The default values on Windows are:</p>
158 <div class="example"><p><code>
159 AcceptFilter http data <br />
160 AcceptFilter https data
163 <p>Window's mpm_winnt interprets the AcceptFilter to toggle the AcceptEx()
164 API, and does not support http protocol buffering. There are two values
165 which utilize the Windows AcceptEx() API and will recycle network
166 sockets between connections. <code>data</code> waits until data has
167 been transmitted as documented above, and the initial data buffer and
168 network endpoint addresses are all retrieved from the single AcceptEx()
169 invocation. <code>connect</code> will use the AcceptEx() API, also
170 retrieve the network endpoint addresses, but like <code>none</code>
171 the <code>connect</code> option does not wait for the initial data
174 <p>On Windows, <code>none</code> uses accept() rather than than AcceptEx()
175 and will not recycle sockets between connections. This is useful for
176 network adapters with broken driver support, as well as some virtual
177 network providers such as vpn drivers, or spam, virus or spyware
182 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
183 <div class="directive-section"><h2><a name="AcceptPathInfo" id="AcceptPathInfo">AcceptPathInfo</a> <a name="acceptpathinfo" id="acceptpathinfo">Directive</a></h2>
184 <table class="directive">
185 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Resources accept trailing pathname information</td></tr>
186 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptPathInfo On|Off|Default</code></td></tr>
187 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AcceptPathInfo Default</code></td></tr>
188 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
189 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
190 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
191 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
192 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.0.30 and later</td></tr>
195 <p>This directive controls whether requests that contain trailing
196 pathname information that follows an actual filename (or
197 non-existent file in an existing directory) will be accepted or
198 rejected. The trailing pathname information can be made
199 available to scripts in the <code>PATH_INFO</code> environment
202 <p>For example, assume the location <code>/test/</code> points to
203 a directory that contains only the single file
204 <code>here.html</code>. Then requests for
205 <code>/test/here.html/more</code> and
206 <code>/test/nothere.html/more</code> both collect
207 <code>/more</code> as <code>PATH_INFO</code>.</p>
209 <p>The three possible arguments for the
210 <code class="directive">AcceptPathInfo</code> directive are:</p>
212 <dt><code>Off</code></dt><dd>A request will only be accepted if it
213 maps to a literal path that exists. Therefore a request with
214 trailing pathname information after the true filename such as
215 <code>/test/here.html/more</code> in the above example will return
216 a 404 NOT FOUND error.</dd>
218 <dt><code>On</code></dt><dd>A request will be accepted if a
219 leading path component maps to a file that exists. The above
220 example <code>/test/here.html/more</code> will be accepted if
221 <code>/test/here.html</code> maps to a valid file.</dd>
223 <dt><code>Default</code></dt><dd>The treatment of requests with
224 trailing pathname information is determined by the <a href="../handler.html">handler</a> responsible for the request.
225 The core handler for normal files defaults to rejecting
226 <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
227 <code>PATH_INFO</code> by default.</dd>
230 <p>The primary purpose of the <code>AcceptPathInfo</code>
231 directive is to allow you to override the handler's choice of
232 accepting or rejecting <code>PATH_INFO</code>. This override is required,
233 for example, when you use a <a href="../filter.html">filter</a>, such
234 as <a href="mod_include.html">INCLUDES</a>, to generate content
235 based on <code>PATH_INFO</code>. The core handler would usually reject
236 the request, so you can use the following configuration to enable
239 <div class="example"><p><code>
240 <Files "mypaths.shtml"><br />
241 <span class="indent">
242 Options +Includes<br />
243 SetOutputFilter INCLUDES<br />
244 AcceptPathInfo On<br />
251 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
252 <div class="directive-section"><h2><a name="AccessFileName" id="AccessFileName">AccessFileName</a> <a name="accessfilename" id="accessfilename">Directive</a></h2>
253 <table class="directive">
254 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Name of the distributed configuration file</td></tr>
255 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AccessFileName <var>filename</var> [<var>filename</var>] ...</code></td></tr>
256 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AccessFileName .htaccess</code></td></tr>
257 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
258 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
259 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
261 <p>While processing a request the server looks for
262 the first existing configuration file from this list of names in
263 every directory of the path to the document, if distributed
264 configuration files are <a href="#allowoverride">enabled for that
265 directory</a>. For example:</p>
267 <div class="example"><p><code>
271 <p>before returning the document
272 <code>/usr/local/web/index.html</code>, the server will read
273 <code>/.acl</code>, <code>/usr/.acl</code>,
274 <code>/usr/local/.acl</code> and <code>/usr/local/web/.acl</code>
275 for directives, unless they have been disabled with</p>
277 <div class="example"><p><code>
278 <Directory /><br />
279 <span class="indent">
280 AllowOverride None<br />
287 <li><code class="directive"><a href="#allowoverride">AllowOverride</a></code></li>
288 <li><a href="../configuring.html">Configuration Files</a></li>
289 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
292 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
293 <div class="directive-section"><h2><a name="AddDefaultCharset" id="AddDefaultCharset">AddDefaultCharset</a> <a name="adddefaultcharset" id="adddefaultcharset">Directive</a></h2>
294 <table class="directive">
295 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Default charset parameter to be added when a response
296 content-type is <code>text/plain</code> or <code>text/html</code></td></tr>
297 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AddDefaultCharset On|Off|<var>charset</var></code></td></tr>
298 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AddDefaultCharset Off</code></td></tr>
299 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
300 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
301 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
302 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
304 <p>This directive specifies a default value for the media type
305 charset parameter (the name of a character encoding) to be added
306 to a response if and only if the response's content-type is either
307 <code>text/plain</code> or <code>text/html</code>. This should override
308 any charset specified in the body of the response via a <code>META</code>
309 element, though the exact behavior is often dependent on the user's client
310 configuration. A setting of <code>AddDefaultCharset Off</code>
311 disables this functionality. <code>AddDefaultCharset On</code> enables
312 a default charset of <code>iso-8859-1</code>. Any other value is assumed
313 to be the <var>charset</var> to be used, which should be one of the
314 <a href="http://www.iana.org/assignments/character-sets">IANA registered
315 charset values</a> for use in Internet media types (MIME types).
318 <div class="example"><p><code>
319 AddDefaultCharset utf-8
322 <p><code class="directive">AddDefaultCharset</code> should only be used when all
323 of the text resources to which it applies are known to be in that
324 character encoding and it is too inconvenient to label their charset
325 individually. One such example is to add the charset parameter
326 to resources containing generated content, such as legacy CGI
327 scripts, that might be vulnerable to cross-site scripting attacks
328 due to user-provided data being included in the output. Note, however,
329 that a better solution is to just fix (or delete) those scripts, since
330 setting a default charset does not protect users that have enabled
331 the "auto-detect character encoding" feature on their browser.</p>
335 <li><code class="directive"><a href="../mod/mod_mime.html#addcharset">AddCharset</a></code></li>
338 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
339 <div class="directive-section"><h2><a name="AllowEncodedSlashes" id="AllowEncodedSlashes">AllowEncodedSlashes</a> <a name="allowencodedslashes" id="allowencodedslashes">Directive</a></h2>
340 <table class="directive">
341 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines whether encoded path separators in URLs are allowed to
342 be passed through</td></tr>
343 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowEncodedSlashes On|Off</code></td></tr>
344 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowEncodedSlashes Off</code></td></tr>
345 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
346 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
347 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
348 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.0.46 and later</td></tr>
350 <p>The <code class="directive">AllowEncodedSlashes</code> directive allows URLs
351 which contain encoded path separators (<code>%2F</code> for <code>/</code>
352 and additionally <code>%5C</code> for <code>\</code> on according systems)
353 to be used. Normally such URLs are refused with a 404 (Not found) error.</p>
355 <p>Turning <code class="directive">AllowEncodedSlashes</code> <code>On</code> is
356 mostly useful when used in conjunction with <code>PATH_INFO</code>.</p>
358 <div class="note"><h3>Note</h3>
359 <p>Allowing encoded slashes does <em>not</em> imply <em>decoding</em>.
360 Occurrences of <code>%2F</code> or <code>%5C</code> (<em>only</em> on
361 according systems) will be left as such in the otherwise decoded URL
367 <li><code class="directive"><a href="#acceptpathinfo">AcceptPathInfo</a></code></li>
370 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
371 <div class="directive-section"><h2><a name="AllowOverride" id="AllowOverride">AllowOverride</a> <a name="allowoverride" id="allowoverride">Directive</a></h2>
372 <table class="directive">
373 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Types of directives that are allowed in
374 <code>.htaccess</code> files</td></tr>
375 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowOverride All|None|<var>directive-type</var>
376 [<var>directive-type</var>] ...</code></td></tr>
377 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowOverride All</code></td></tr>
378 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
379 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
380 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
382 <p>When the server finds an <code>.htaccess</code> file (as
383 specified by <code class="directive"><a href="#accessfilename">AccessFileName</a></code>)
384 it needs to know which directives declared in that file can override
385 earlier configuration directives.</p>
387 <div class="note"><h3>Only available in <Directory> sections</h3>
388 <code class="directive">AllowOverride</code> is valid only in
389 <code class="directive"><a href="#directory"><Directory></a></code>
390 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
391 <code class="directive"><a href="#files"><Files></a></code> sections.
394 <p>When this directive is set to <code>None</code>, then
395 <a href="#accessfilename">.htaccess</a> files are completely ignored.
396 In this case, the server will not even attempt to read
397 <code>.htaccess</code> files in the filesystem.</p>
399 <p>When this directive is set to <code>All</code>, then any
400 directive which has the .htaccess <a href="directive-dict.html#Context">Context</a> is allowed in
401 <code>.htaccess</code> files.</p>
403 <p>The <var>directive-type</var> can be one of the following
404 groupings of directives.</p>
411 Allow use of the authorization directives (<code class="directive"><a href="../mod/mod_authn_dbm.html#authdbmgroupfile">AuthDBMGroupFile</a></code>,
412 <code class="directive"><a href="../mod/mod_authn_dbm.html#authdbmuserfile">AuthDBMUserFile</a></code>,
413 <code class="directive"><a href="../mod/mod_authz_groupfile.html#authgroupfile">AuthGroupFile</a></code>,
414 <code class="directive"><a href="../mod/mod_authn_core.html#authname">AuthName</a></code>,
415 <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>
420 Allow use of the directives controlling document types
421 (<code class="directive"><a href="#errordocument">ErrorDocument</a></code>,
422 <code class="directive"><a href="#forcetype">ForceType</a></code>,
423 <code class="directive"><a href="../mod/mod_negotiation.html#languagepriority">LanguagePriority</a></code>,
424 <code class="directive"><a href="#sethandler">SetHandler</a></code>,
425 <code class="directive"><a href="#setinputfilter">SetInputFilter</a></code>,
426 <code class="directive"><a href="#setoutputfilter">SetOutputFilter</a></code>, and
427 <code class="module"><a href="../mod/mod_mime.html">mod_mime</a></code> Add* and Remove* directives),
428 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>),
429 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> directives <code class="directive"><a href="../mod/mod_rewrite.html#rewriteengine">RewriteEngine</a></code>, <code class="directive"><a href="../mod/mod_rewrite.html#rewriteoptions">RewriteOptions</a></code>, <code class="directive"><a href="../mod/mod_rewrite.html#rewritebase">RewriteBase</a></code>, <code class="directive"><a href="../mod/mod_rewrite.html#rewritecond">RewriteCond</a></code>, <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code>) and
430 <code class="directive"><a href="../mod/mod_actions.html#action">Action</a></code> from
431 <code class="module"><a href="../mod/mod_actions.html">mod_actions</a></code>.
437 Allow use of the directives controlling directory indexing
438 (<code class="directive"><a href="../mod/mod_autoindex.html#adddescription">AddDescription</a></code>,
439 <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>,
440 <code class="directive"><a href="../mod/mod_autoindex.html#addiconbytype">AddIconByType</a></code>,
441 <code class="directive"><a href="../mod/mod_autoindex.html#defaulticon">DefaultIcon</a></code>, <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>, <code class="directive"><a href="../mod/mod_autoindex.html#fancyindexing">FancyIndexing</a></code>, <code class="directive"><a href="../mod/mod_autoindex.html#headername">HeaderName</a></code>, <code class="directive"><a href="../mod/mod_autoindex.html#indexignore">IndexIgnore</a></code>, <code class="directive"><a href="../mod/mod_autoindex.html#indexoptions">IndexOptions</a></code>, <code class="directive"><a href="../mod/mod_autoindex.html#readmename">ReadmeName</a></code>,
447 Allow use of the directives controlling host access (<code class="directive"><a href="../mod/mod_authz_host.html#allow">Allow</a></code>, <code class="directive"><a href="../mod/mod_authz_host.html#deny">Deny</a></code> and <code class="directive"><a href="../mod/mod_authz_host.html#order">Order</a></code>).</dd>
449 <dt>Options[=<var>Option</var>,...]</dt>
452 Allow use of the directives controlling specific directory
453 features (<code class="directive"><a href="#options">Options</a></code> and
454 <code class="directive"><a href="../mod/mod_include.html#xbithack">XBitHack</a></code>).
455 An equal sign may be given followed by a comma (but no spaces)
456 separated lists of options that may be set using the <code class="directive"><a href="#options">Options</a></code> command.</dd>
461 <div class="example"><p><code>
462 AllowOverride AuthConfig Indexes
465 <p>In the example above all directives that are neither in the group
466 <code>AuthConfig</code> nor <code>Indexes</code> cause an internal
469 <div class="note"><p>For security and performance reasons, do not set
470 <code>AllowOverride</code> to anything other than <code>None</code>
471 in your <code><Directory /></code> block. Instead, find (or
472 create) the <code><Directory></code> block that refers to the
473 directory where you're actually planning to place a
474 <code>.htaccess</code> file.</p>
479 <li><code class="directive"><a href="#accessfilename">AccessFileName</a></code></li>
480 <li><a href="../configuring.html">Configuration Files</a></li>
481 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
484 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
485 <div class="directive-section"><h2><a name="CGIMapExtension" id="CGIMapExtension">CGIMapExtension</a> <a name="cgimapextension" id="cgimapextension">Directive</a></h2>
486 <table class="directive">
487 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
489 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CGIMapExtension <var>cgi-path</var> <var>.extension</var></code></td></tr>
490 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
491 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
492 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
493 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
494 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>NetWare only</td></tr>
496 <p>This directive is used to control how Apache httpd finds the
497 interpreter used to run CGI scripts. For example, setting
498 <code>CGIMapExtension sys:\foo.nlm .foo</code> will
499 cause all CGI script files with a <code>.foo</code> extension to
500 be passed to the FOO interpreter.</p>
503 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
504 <div class="directive-section"><h2><a name="ContentDigest" id="ContentDigest">ContentDigest</a> <a name="contentdigest" id="contentdigest">Directive</a></h2>
505 <table class="directive">
506 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables the generation of <code>Content-MD5</code> HTTP Response
508 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ContentDigest On|Off</code></td></tr>
509 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ContentDigest Off</code></td></tr>
510 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
511 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
512 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
513 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
515 <p>This directive enables the generation of
516 <code>Content-MD5</code> headers as defined in RFC1864
517 respectively RFC2616.</p>
519 <p>MD5 is an algorithm for computing a "message digest"
520 (sometimes called "fingerprint") of arbitrary-length data, with
521 a high degree of confidence that any alterations in the data
522 will be reflected in alterations in the message digest.</p>
524 <p>The <code>Content-MD5</code> header provides an end-to-end
525 message integrity check (MIC) of the entity-body. A proxy or
526 client may check this header for detecting accidental
527 modification of the entity-body in transit. Example header:</p>
529 <div class="example"><p><code>
530 Content-MD5: AuLb7Dp1rqtRtxz2m9kRpA==
533 <p>Note that this can cause performance problems on your server
534 since the message digest is computed on every request (the
535 values are not cached).</p>
537 <p><code>Content-MD5</code> is only sent for documents served
538 by the <code class="module"><a href="../mod/core.html">core</a></code>, and not by any module. For example,
539 SSI documents, output from CGI scripts, and byte range responses
540 do not have this header.</p>
543 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
544 <div class="directive-section"><h2><a name="DefaultType" id="DefaultType">DefaultType</a> <a name="defaulttype" id="defaulttype">Directive</a></h2>
545 <table class="directive">
546 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>This directive has no effect other than to emit warnings
547 if the value is not <code>none</code>. In prior versions, DefaultType
548 would specify a default media type to assign to response content for
549 which no other media type configuration could be found.
551 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultType <var>media-type|none</var></code></td></tr>
552 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultType none</code></td></tr>
553 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
554 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
555 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
556 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
557 <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>
559 <p>This directive has been disabled. For backwards compatibility
560 of configuration files, it may be specified with the value
561 <code>none</code>, meaning no default media type. For example:</p>
563 <div class="example"><p><code>
567 <p><code>DefaultType None</code> is only available in
568 httpd-2.2.7 and later.</p>
570 <p>Use the mime.types configuration file and the
571 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code> to configure media
572 type assignments via file extensions, or the
573 <code class="directive"><a href="#forcetype">ForceType</a></code> directive to configure
574 the media type for specific resources. Otherwise, the server will
575 send the response without a Content-Type header field and the
576 recipient may attempt to guess the media type.</p>
579 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
580 <div class="directive-section"><h2><a name="Define" id="Define">Define</a> <a name="define" id="define">Directive</a></h2>
581 <table class="directive">
582 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Define the existence of a variable</td></tr>
583 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Define <var>parameter-name</var></code></td></tr>
584 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
585 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
586 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
588 <p>Equivalent to passing the <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</p>
589 <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
590 <code>-D</code> arguments in any startup scripts.</p>
593 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
594 <div class="directive-section"><h2><a name="Directory" id="Directory"><Directory></a> <a name="directory" id="directory">Directive</a></h2>
595 <table class="directive">
596 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose a group of directives that apply only to the
597 named file-system directory and sub-directories</td></tr>
598 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Directory <var>directory-path</var>>
599 ... </Directory></code></td></tr>
600 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
601 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
602 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
604 <p><code class="directive"><Directory></code> and
605 <code></Directory></code> are used to enclose a group of
606 directives that will apply only to the named directory and
607 sub-directories of that directory. Any directive that is allowed
608 in a directory context may be used. <var>Directory-path</var> is
609 either the full path to a directory, or a wild-card string using
610 Unix shell-style matching. In a wild-card string, <code>?</code> matches
611 any single character, and <code>*</code> matches any sequences of
612 characters. You may also use <code>[]</code> character ranges. None
613 of the wildcards match a `/' character, so <code><Directory
614 /*/public_html></code> will not match
615 <code>/home/user/public_html</code>, but <code><Directory
616 /home/*/public_html></code> will match. Example:</p>
618 <div class="example"><p><code>
619 <Directory /usr/local/httpd/htdocs><br />
620 <span class="indent">
621 Options Indexes FollowSymLinks<br />
627 <p>Be careful with the <var>directory-path</var> arguments:
628 They have to literally match the filesystem path which Apache httpd uses
629 to access the files. Directives applied to a particular
630 <code><Directory></code> will not apply to files accessed from
631 that same directory via a different path, such as via different symbolic
635 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular
636 expressions</a> can also be used, with the addition of the
637 <code>~</code> character. For example:</p>
639 <div class="example"><p><code>
640 <Directory ~ "^/www/.*/[0-9]{3}">
643 <p>would match directories in <code>/www/</code> that consisted of
646 <p>If multiple (non-regular expression) <code class="directive"><Directory></code> sections
647 match the directory (or one of its parents) containing a document,
648 then the directives are applied in the order of shortest match
649 first, interspersed with the directives from the <a href="#accessfilename">.htaccess</a> files. For example,
652 <div class="example"><p><code>
653 <Directory /><br />
654 <span class="indent">
655 AllowOverride None<br />
657 </Directory><br />
659 <Directory /home/><br />
660 <span class="indent">
661 AllowOverride FileInfo<br />
666 <p>for access to the document <code>/home/web/dir/doc.html</code>
670 <li>Apply directive <code>AllowOverride None</code>
671 (disabling <code>.htaccess</code> files).</li>
673 <li>Apply directive <code>AllowOverride FileInfo</code> (for
674 directory <code>/home</code>).</li>
676 <li>Apply any <code>FileInfo</code> directives in
677 <code>/home/.htaccess</code>, <code>/home/web/.htaccess</code> and
678 <code>/home/web/dir/.htaccess</code> in that order.</li>
681 <p>Regular expressions are not considered until after all of the
682 normal sections have been applied. Then all of the regular
683 expressions are tested in the order they appeared in the
684 configuration file. For example, with</p>
686 <div class="example"><p><code>
687 <Directory ~ abc$><br />
688 <span class="indent">
689 # ... directives here ...<br />
694 <p>the regular expression section won't be considered until after
695 all normal <code class="directive"><Directory></code>s and
696 <code>.htaccess</code> files have been applied. Then the regular
697 expression will match on <code>/home/abc/public_html/abc</code> and
698 the corresponding <code class="directive"><Directory></code> will
701 <p><strong>Note that the default access for
702 <code><Directory /></code> is <code>Allow from All</code>.
703 This means that Apache httpd will serve any file mapped from an URL. It is
704 recommended that you change this with a block such
707 <div class="example"><p><code>
708 <Directory /><br />
709 <span class="indent">
710 Order Deny,Allow<br />
716 <p><strong>and then override this for directories you
717 <em>want</em> accessible. See the <a href="../misc/security_tips.html">Security Tips</a> page for more
718 details.</strong></p>
720 <p>The directory sections occur in the <code>httpd.conf</code> file.
721 <code class="directive"><Directory></code> directives
722 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>
726 <li><a href="../sections.html">How <Directory>,
727 <Location> and <Files> sections work</a> for an
728 explanation of how these different sections are combined when a
729 request is received</li>
732 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
733 <div class="directive-section"><h2><a name="DirectoryMatch" id="DirectoryMatch"><DirectoryMatch></a> <a name="directorymatch" id="directorymatch">Directive</a></h2>
734 <table class="directive">
735 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose directives that apply to
736 file-system directories matching a regular expression.</td></tr>
737 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><DirectoryMatch <var>regex</var>>
738 ... </DirectoryMatch></code></td></tr>
739 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
740 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
741 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
743 <p><code class="directive"><DirectoryMatch></code> and
744 <code></DirectoryMatch></code> are used to enclose a group
745 of directives which will apply only to the named directory,
746 the same as <code class="directive"><a href="#directory"><Directory></a></code>.
747 However, it takes as an argument a
748 <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>. For example:</p>
750 <div class="example"><p><code>
751 <DirectoryMatch "^/www/(.+/)?[0-9]{3}">
754 <p>would match directories in <code>/www/</code> that consisted of three
757 <div class="note"><h3>Compatability</h3>
758 Prior to 2.3.9, this directive implicitly applied to sub-directories
759 (like <code class="directive"><a href="#directory"><Directory></a></code>) and
760 could not match the end of line symbol ($). In 2.3.9 and later,
761 only directories that match the expression are affected by the enclosed
765 <div class="note"><h3>Trailing Slash</h3>
766 This directive applies to requests for directories that may or may
767 not end in a trailing slash, so expressions that are anchored to the
768 end of line ($) must be written with care.
773 <li><code class="directive"><a href="#directory"><Directory></a></code> for
774 a description of how regular expressions are mixed in with normal
775 <code class="directive"><Directory></code>s</li>
776 <li><a href="../sections.html">How <Directory>, <Location> and
777 <Files> sections work</a> for an explanation of how these different
778 sections are combined when a request is received</li>
781 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
782 <div class="directive-section"><h2><a name="DocumentRoot" id="DocumentRoot">DocumentRoot</a> <a name="documentroot" id="documentroot">Directive</a></h2>
783 <table class="directive">
784 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory that forms the main document tree visible
785 from the web</td></tr>
786 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DocumentRoot <var>directory-path</var></code></td></tr>
787 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DocumentRoot /usr/local/apache/htdocs</code></td></tr>
788 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
789 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
790 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
792 <p>This directive sets the directory from which <code class="program"><a href="../programs/httpd.html">httpd</a></code>
793 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
794 path from the requested URL to the document root to make the
795 path to the document. Example:</p>
797 <div class="example"><p><code>
798 DocumentRoot /usr/web
802 <code>http://www.my.host.com/index.html</code> refers to
803 <code>/usr/web/index.html</code>. If the <var>directory-path</var> is
804 not absolute then it is assumed to be relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
806 <p>The <code class="directive">DocumentRoot</code> should be specified without
807 a trailing slash.</p>
811 <li><a href="../urlmapping.html#documentroot">Mapping URLs to Filesystem
815 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
816 <div class="directive-section"><h2><a name="EnableMMAP" id="EnableMMAP">EnableMMAP</a> <a name="enablemmap" id="enablemmap">Directive</a></h2>
817 <table class="directive">
818 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use memory-mapping to read files during delivery</td></tr>
819 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableMMAP On|Off</code></td></tr>
820 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableMMAP On</code></td></tr>
821 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
822 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
823 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
824 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
826 <p>This directive controls whether the <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use
827 memory-mapping if it needs to read the contents of a file during
828 delivery. By default, when the handling of a request requires
829 access to the data within a file -- for example, when delivering a
830 server-parsed file using <code class="module"><a href="../mod/mod_include.html">mod_include</a></code> -- Apache httpd
831 memory-maps the file if the OS supports it.</p>
833 <p>This memory-mapping sometimes yields a performance improvement.
834 But in some environments, it is better to disable the memory-mapping
835 to prevent operational problems:</p>
838 <li>On some multiprocessor systems, memory-mapping can reduce the
839 performance of the <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</li>
840 <li>Deleting or truncating a file while <code class="program"><a href="../programs/httpd.html">httpd</a></code>
841 has it memory-mapped can cause <code class="program"><a href="../programs/httpd.html">httpd</a></code> to
842 crash with a segmentation fault.
846 <p>For server configurations that are vulnerable to these problems,
847 you should disable memory-mapping of delivered files by specifying:</p>
849 <div class="example"><p><code>
853 <p>For NFS mounted files, this feature may be disabled explicitly for
854 the offending files by specifying:</p>
856 <div class="example"><p><code>
857 <Directory "/path-to-nfs-files">
858 <span class="indent">
865 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
866 <div class="directive-section"><h2><a name="EnableSendfile" id="EnableSendfile">EnableSendfile</a> <a name="enablesendfile" id="enablesendfile">Directive</a></h2>
867 <table class="directive">
868 <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>
869 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableSendfile On|Off</code></td></tr>
870 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableSendfile Off</code></td></tr>
871 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
872 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
873 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
874 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
875 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in version 2.0.44 and later. Default changed to Off in
876 version 2.3.9.</td></tr>
878 <p>This directive controls whether <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use the
879 sendfile support from the kernel to transmit file contents to the client.
880 By default, when the handling of a request requires no access
881 to the data within a file -- for example, when delivering a
882 static file -- Apache httpd uses sendfile to deliver the file contents
883 without ever reading the file if the OS supports it.</p>
885 <p>This sendfile mechanism avoids separate read and send operations,
886 and buffer allocations. But on some platforms or within some
887 filesystems, it is better to disable this feature to avoid
888 operational problems:</p>
891 <li>Some platforms may have broken sendfile support that the build
892 system did not detect, especially if the binaries were built on
893 another box and moved to such a machine with broken sendfile
895 <li>On Linux the use of sendfile triggers TCP-checksum
896 offloading bugs on certain networking cards when using IPv6.</li>
897 <li>On Linux on Itanium, sendfile may be unable to handle files
898 over 2GB in size.</li>
899 <li>With a network-mounted <code class="directive"><a href="#documentroot">DocumentRoot</a></code> (e.g., NFS, SMB, CIFS, FUSE),
900 the kernel may be unable to serve the network file through
904 <p>For server configurations that are not vulnerable to these problems,
905 you may enable this feature by specifying:</p>
907 <div class="example"><p><code>
911 <p>For network mounted files, this feature may be disabled explicitly
912 for the offending files by specifying:</p>
914 <div class="example"><p><code>
915 <Directory "/path-to-nfs-files">
916 <span class="indent">
921 <p>Please note that the per-directory and .htaccess configuration
922 of <code class="directive">EnableSendfile</code> is not supported by
923 <code class="module"><a href="../mod/mod_disk_cache.html">mod_disk_cache</a></code>.
924 Only global definition of <code class="directive">EnableSendfile</code>
925 is taken into account by the module.
929 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
930 <div class="directive-section"><h2><a name="ErrorDocument" id="ErrorDocument">ErrorDocument</a> <a name="errordocument" id="errordocument">Directive</a></h2>
931 <table class="directive">
932 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>What the server will return to the client
933 in case of an error</td></tr>
934 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ErrorDocument <var>error-code</var> <var>document</var></code></td></tr>
935 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
936 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
937 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
938 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
939 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Quoting syntax for text messages is different in Apache HTTP Server
942 <p>In the event of a problem or error, Apache httpd can be configured
943 to do one of four things,</p>
946 <li>output a simple hardcoded error message</li>
948 <li>output a customized message</li>
950 <li>redirect to a local <var>URL-path</var> to handle the
953 <li>redirect to an external <var>URL</var> to handle the
957 <p>The first option is the default, while options 2-4 are
958 configured using the <code class="directive">ErrorDocument</code>
959 directive, which is followed by the HTTP response code and a URL
960 or a message. Apache httpd will sometimes offer additional information
961 regarding the problem/error.</p>
963 <p>URLs can begin with a slash (/) for local web-paths (relative
964 to the <code class="directive"><a href="#documentroot">DocumentRoot</a></code>), or be a
965 full URL which the client can resolve. Alternatively, a message
966 can be provided to be displayed by the browser. Examples:</p>
968 <div class="example"><p><code>
969 ErrorDocument 500 http://foo.example.com/cgi-bin/tester<br />
970 ErrorDocument 404 /cgi-bin/bad_urls.pl<br />
971 ErrorDocument 401 /subscription_info.html<br />
972 ErrorDocument 403 "Sorry can't allow you access today"
975 <p>Additionally, the special value <code>default</code> can be used
976 to specify Apache httpd's simple hardcoded message. While not required
977 under normal circumstances, <code>default</code> will restore
978 Apache httpd's simple hardcoded message for configurations that would
979 otherwise inherit an existing <code class="directive">ErrorDocument</code>.</p>
981 <div class="example"><p><code>
982 ErrorDocument 404 /cgi-bin/bad_urls.pl<br /><br />
983 <Directory /web/docs><br />
984 <span class="indent">
985 ErrorDocument 404 default<br />
990 <p>Note that when you specify an <code class="directive">ErrorDocument</code>
991 that points to a remote URL (ie. anything with a method such as
992 <code>http</code> in front of it), Apache HTTP Server will send a redirect to the
993 client to tell it where to find the document, even if the
994 document ends up being on the same server. This has several
995 implications, the most important being that the client will not
996 receive the original error status code, but instead will
997 receive a redirect status code. This in turn can confuse web
998 robots and other clients which try to determine if a URL is
999 valid using the status code. In addition, if you use a remote
1000 URL in an <code>ErrorDocument 401</code>, the client will not
1001 know to prompt the user for a password since it will not
1002 receive the 401 status code. Therefore, <strong>if you use an
1003 <code>ErrorDocument 401</code> directive then it must refer to a local
1004 document.</strong></p>
1006 <p>Microsoft Internet Explorer (MSIE) will by default ignore
1007 server-generated error messages when they are "too small" and substitute
1008 its own "friendly" error messages. The size threshold varies depending on
1009 the type of error, but in general, if you make your error document
1010 greater than 512 bytes, then MSIE will show the server-generated
1011 error rather than masking it. More information is available in
1012 Microsoft Knowledge Base article <a href="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q294807">Q294807</a>.</p>
1014 <p>Although most error messages can be overriden, there are certain
1015 circumstances where the internal messages are used regardless of the
1016 setting of <code class="directive"><a href="#errordocument">ErrorDocument</a></code>. In
1017 particular, if a malformed request is detected, normal request processing
1018 will be immediately halted and the internal error message returned.
1019 This is necessary to guard against security problems caused by
1022 <p>If you are using mod_proxy, you may wish to enable
1023 <code class="directive"><a href="../mod/mod_proxy.html#proxyerroroverride">ProxyErrorOverride</a></code> so that you can provide
1024 custom error messages on behalf of your Origin servers. If you don't enable ProxyErrorOverride,
1025 Apache httpd will not generate custom error documents for proxied content.</p>
1029 <li><a href="../custom-error.html">documentation of
1030 customizable responses</a></li>
1033 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1034 <div class="directive-section"><h2><a name="ErrorLog" id="ErrorLog">ErrorLog</a> <a name="errorlog" id="errorlog">Directive</a></h2>
1035 <table class="directive">
1036 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Location where the server will log errors</td></tr>
1037 <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>
1038 <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>
1039 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1040 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1041 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1043 <p>The <code class="directive">ErrorLog</code> directive sets the name of
1044 the file to which the server will log any errors it encounters. If
1045 the <var>file-path</var> is not absolute then it is assumed to be
1046 relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>
1048 <div class="example"><h3>Example</h3><p><code>
1049 ErrorLog /var/log/httpd/error_log
1052 <p>If the <var>file-path</var>
1053 begins with a pipe character "<code>|</code>" then it is assumed to be a
1054 command to spawn to handle the error log.</p>
1056 <div class="example"><h3>Example</h3><p><code>
1057 ErrorLog "|/usr/local/bin/httpd_errors"
1060 <p>See the notes on <a href="../logs.html#piped">piped logs</a> for
1061 more information.</p>
1063 <p>Using <code>syslog</code> instead of a filename enables logging
1064 via syslogd(8) if the system supports it. The default is to use
1065 syslog facility <code>local7</code>, but you can override this by
1066 using the <code>syslog:<var>facility</var></code> syntax where
1067 <var>facility</var> can be one of the names usually documented in
1070 <div class="example"><h3>Example</h3><p><code>
1071 ErrorLog syslog:user
1074 <p>SECURITY: See the <a href="../misc/security_tips.html#serverroot">security tips</a>
1075 document for details on why your security could be compromised
1076 if the directory where log files are stored is writable by
1077 anyone other than the user that starts the server.</p>
1078 <div class="warning"><h3>Note</h3>
1079 <p>When entering a file path on non-Unix platforms, care should be taken
1080 to make sure that only forward slashed are used even though the platform
1081 may allow the use of back slashes. In general it is a good idea to always
1082 use forward slashes throughout the configuration files.</p>
1087 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1088 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1091 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1092 <div class="directive-section"><h2><a name="ErrorLogFormat" id="ErrorLogFormat">ErrorLogFormat</a> <a name="errorlogformat" id="errorlogformat">Directive</a></h2>
1093 <table class="directive">
1094 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Format specification for error log entries</td></tr>
1095 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code> ErrorLog [connection|request] <var>format</var></code></td></tr>
1096 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1097 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1098 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1099 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.3.9 and later</td></tr>
1101 <p><code class="directive">ErrorLogFormat</code> allows to specify what
1102 supplementary information is logged in the error log in addition to the
1103 actual log message.</p>
1105 <div class="example"><h3>Simple example</h3><p><code>
1106 ErrorLogFormat "[%t] [%l] [pid %P] %F: %E: [client %a] %M"
1109 <p>Specifying <code>connection</code> or <code>request</code> as first
1110 paramter allows to specify additional formats, causing additional
1111 information to be logged when the first message is logged for a specific
1112 connection or request, respectivly. This additional information is only
1113 logged once per connection/request. If a connection or request is processed
1114 without causing any log message, the additional information is not logged
1117 <p>It can happen that some format string items do not produce output. For
1118 example, the Referer header is only present if the log message is
1119 associated to a request and the log message happens at a time when the
1120 Referer header has already been read from the client. If no output is
1121 produced, the default behaviour is to delete everything from the preceeding
1122 space character to the next space character. This means the log line is
1123 implicitly divided into fields on non-whitespace to whitespace transitions.
1124 If a format string item does not produce output, the whole field is
1125 ommitted. For example, if the remote address <code>%a</code> in the log
1126 format <code>[%t] [%l] [%a] %M </code> is not available, the surrounding
1127 brackets are not logged either. Space characters can be escaped with a
1128 backslash to prevent them from delimiting a field. The combination '% '
1129 (percent space) is a zero-witdh field delimiter that does not produce any
1132 <p>The above behaviour can be changed by adding flags to the format string
1133 item. A <code>-</code> (minus) flag causes a minus to be logged if the
1134 respective item does not produce any output. In once-per-connection/request
1135 formats, it is also possible to use the <code>+</code> (plus) flag. If an
1136 item with the plus flag does not produce any output, the whole line is
1139 <p>Some format string items accept additional parameters in braces.</p>
1141 <table class="bordered"><tr class="header"><th>Format String</th> <th>Description</th></tr>
1142 <tr><td><code>%%</code></td>
1143 <td>The percent sign</td></tr>
1144 <tr class="odd"><td><code>%...a</code></td>
1145 <td>Remote IP-address and port</td></tr>
1146 <tr><td><code>%...A</code></td>
1147 <td>Local IP-address and port</td></tr>
1148 <tr class="odd"><td><code>%...{name}e</code></td>
1149 <td>Request environment variable <code>name</code></td></tr>
1150 <tr><td><code>%...E</code></td>
1151 <td>APR/OS error status code and string</td></tr>
1152 <tr class="odd"><td><code>%...F</code></td>
1153 <td>Source file name and line number of the log call</td></tr>
1154 <tr><td><code>%...{name}i</code></td>
1155 <td>Request header <code>name</code></td></tr>
1156 <tr class="odd"><td><code>%...k</code></td>
1157 <td>Number of keep-alive requests on this connection</td></tr>
1158 <tr><td><code>%...l</code></td>
1159 <td>Loglevel of the message</td></tr>
1160 <tr class="odd"><td><code>%...L</code></td>
1161 <td>Log ID of the request</td></tr>
1162 <tr><td><code>%...{c}L</code></td>
1163 <td>Log ID of the connection</td></tr>
1164 <tr class="odd"><td><code>%...{C}L</code></td>
1165 <td>Log ID of the connection if used in connection scope, empty otherwise</td></tr>
1166 <tr><td><code>%...m</code></td>
1167 <td>Name of the module logging the message</td></tr>
1168 <tr class="odd"><td><code>%M</code></td>
1169 <td>The actual log message</td></tr>
1170 <tr><td><code>%...{name}n</code></td>
1171 <td>Request note <code>name</code></td></tr>
1172 <tr class="odd"><td><code>%...P</code></td>
1173 <td>Process ID of current process</td></tr>
1174 <tr><td><code>%...T</code></td>
1175 <td>Thread ID of current thread</td></tr>
1176 <tr class="odd"><td><code>%...t</code></td>
1177 <td>The current time</td></tr>
1178 <tr><td><code>%...{u}t</code></td>
1179 <td>The current time including micro-seconds</td></tr>
1180 <tr class="odd"><td><code>%...{cu}t</code></td>
1181 <td>The current time in compact ISO 8601 format, including
1182 micro-seconds</td></tr>
1183 <tr><td><code>\ </code> (backslash space)</td>
1184 <td>Non-field delimiting space</td></tr>
1185 <tr class="odd"><td><code>% </code> (percent space)</td>
1186 <td>Field delimiter (no output)</td></tr>
1189 <p>The log ID format <code>%L</code> produces a unique id for a connection
1190 or request. This can be used to correlate which log lines belong to the
1191 same connection or request, which request happens on which connection.
1192 A <code>%L</code> format string is also available in
1193 <code class="module"><a href="../mod/mod_log_config.html">mod_log_config</a></code>, to allow to correlate access log entries
1194 with error log lines.</p>
1196 <div class="example"><h3>Example (somewhat similar to default format)</h3><p><code>
1197 ErrorLogFormat "[%{u}t] [%-m:%l] [pid %P] %F: %E: [client\ %a]
1198 %M% ,\ referer\ %{Referer}i"
1201 <div class="example"><h3>Example (similar to the 2.2.x format)</h3><p><code>
1202 ErrorLogFormat "[%t] [%l] %F: %E: [client\ %a]
1203 %M% ,\ referer\ %{Referer}i"
1206 <div class="example"><h3>Advanced example with request/connection log IDs</h3><p><code>
1207 ErrorLogFormat "[%{uc}t] [%-m:%-l] [R:%L] [C:%{C}L] %M"<br />
1208 ErrorLogFormat request "[%{uc}t] [R:%L] Request %k on C:%{c}L pid:%P tid:%T"<br />
1209 ErrorLogFormat request "[%{uc}t] [R:%L] UA:'%+{User-Agent}i'"<br />
1210 ErrorLogFormat request "[%{uc}t] [R:%L] Referer:'%+{Referer}i'"<br />
1211 ErrorLogFormat connection "[%{uc}t] [C:%{c}L] local\ %a remote\ %A"<br />
1217 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
1218 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1219 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1222 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1223 <div class="directive-section"><h2><a name="ExtendedStatus" id="ExtendedStatus">ExtendedStatus</a> <a name="extendedstatus" id="extendedstatus">Directive</a></h2>
1224 <table class="directive">
1225 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Keep track of extended status information for each
1227 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ExtendedStatus On|Off</code></td></tr>
1228 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ExtendedStatus Off[*]</code></td></tr>
1229 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
1230 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1231 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1233 <p>This option tracks additional data per worker about the
1234 currently executing request, and a utilization summary; you
1235 can see these variables during runtime by configuring
1236 <code class="module"><a href="../mod/mod_status.html">mod_status</a></code>. Note that other modules may
1237 rely on this scoreboard.</p>
1239 <p>This setting applies to the entire server, and cannot be
1240 enabled or disabled on a virtualhost-by-virtualhost basis.
1241 The collection of extended status information can slow down
1242 the server. Also note that this setting cannot be changed
1243 during a graceful restart.</p>
1246 <p>Note that loading <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> will change
1247 the default behavior to ExtendedStatus On, while other
1248 third party modules may do the same. Such modules rely on
1249 collecting detailed information about the state of all workers.
1250 The default is changed by <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> beginning
1251 with version 2.3.6; the previous default was always Off.</p>
1256 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1257 <div class="directive-section"><h2><a name="FileETag" id="FileETag">FileETag</a> <a name="fileetag" id="fileetag">Directive</a></h2>
1258 <table class="directive">
1259 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>File attributes used to create the ETag
1260 HTTP response header for static files</td></tr>
1261 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>FileETag <var>component</var> ...</code></td></tr>
1262 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>FileETag INode MTime Size</code></td></tr>
1263 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1264 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1265 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1266 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1269 The <code class="directive">FileETag</code> directive configures the file
1270 attributes that are used to create the <code>ETag</code> (entity
1271 tag) response header field when the document is based on a static file.
1272 (The <code>ETag</code> value is used in cache management to save
1273 network bandwidth.) The
1274 <code class="directive">FileETag</code> directive allows you to choose
1275 which of these -- if any -- should be used. The recognized keywords are:
1279 <dt><strong>INode</strong></dt>
1280 <dd>The file's i-node number will be included in the calculation</dd>
1281 <dt><strong>MTime</strong></dt>
1282 <dd>The date and time the file was last modified will be included</dd>
1283 <dt><strong>Size</strong></dt>
1284 <dd>The number of bytes in the file will be included</dd>
1285 <dt><strong>All</strong></dt>
1286 <dd>All available fields will be used. This is equivalent to:
1287 <div class="example"><p><code>FileETag INode MTime Size</code></p></div></dd>
1288 <dt><strong>None</strong></dt>
1289 <dd>If a document is file-based, no <code>ETag</code> field will be
1290 included in the response</dd>
1293 <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
1294 keywords may be prefixed with either <code>+</code> or <code>-</code>,
1295 which allow changes to be made to the default setting inherited
1296 from a broader scope. Any keyword appearing without such a prefix
1297 immediately and completely cancels the inherited setting.</p>
1299 <p>If a directory's configuration includes
1300 <code>FileETag INode MTime Size</code>, and a
1301 subdirectory's includes <code>FileETag -INode</code>,
1302 the setting for that subdirectory (which will be inherited by
1303 any sub-subdirectories that don't override it) will be equivalent to
1304 <code>FileETag MTime Size</code>.</p>
1305 <div class="warning"><h3>Warning</h3>
1306 Do not change the default for directories or locations that have WebDAV
1307 enabled and use <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> as a storage provider.
1308 <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> uses <code>INode MTime Size</code>
1309 as a fixed format for <code>ETag</code> comparisons on conditional requests.
1310 These conditional requests will break if the <code>ETag</code> format is
1311 changed via <code class="directive">FileETag</code>.
1313 <div class="note"><h3>Server Side Includes</h3>
1314 An ETag is not generated for responses parsed by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>,
1315 since the response entity can change without a change of the INode, MTime, or Size
1316 of the static file with embedded SSI directives.
1321 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1322 <div class="directive-section"><h2><a name="Files" id="Files"><Files></a> <a name="files" id="files">Directive</a></h2>
1323 <table class="directive">
1324 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to matched
1326 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Files <var>filename</var>> ... </Files></code></td></tr>
1327 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1328 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1329 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1330 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1332 <p>The <code class="directive"><Files></code> directive
1333 limits the scope of the enclosed directives by filename. It is comparable
1334 to the <code class="directive"><a href="#directory"><Directory></a></code>
1335 and <code class="directive"><a href="#location"><Location></a></code>
1336 directives. It should be matched with a <code></Files></code>
1337 directive. The directives given within this section will be applied to
1338 any object with a basename (last component of filename) matching the
1339 specified filename. <code class="directive"><Files></code>
1340 sections are processed in the order they appear in the
1341 configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
1342 <code>.htaccess</code> files are read, but before <code class="directive"><a href="#location"><Location></a></code> sections. Note
1343 that <code class="directive"><Files></code> can be nested
1344 inside <code class="directive"><a href="#directory"><Directory></a></code> sections to restrict the
1345 portion of the filesystem they apply to.</p>
1347 <p>The <var>filename</var> argument should include a filename, or
1348 a wild-card string, where <code>?</code> matches any single character,
1349 and <code>*</code> matches any sequences of characters.
1350 <a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
1351 can also be used, with the addition of the
1352 <code>~</code> character. For example:</p>
1354 <div class="example"><p><code>
1355 <Files ~ "\.(gif|jpe?g|png)$">
1358 <p>would match most common Internet graphics formats. <code class="directive"><a href="#filesmatch"><FilesMatch></a></code> is preferred,
1361 <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
1362 <code>.htaccess</code> files. This allows users to control access to
1363 their own files, at a file-by-file level.</p>
1368 <li><a href="../sections.html">How <Directory>, <Location>
1369 and <Files> sections work</a> for an explanation of how these
1370 different sections are combined when a request is received</li>
1373 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1374 <div class="directive-section"><h2><a name="FilesMatch" id="FilesMatch"><FilesMatch></a> <a name="filesmatch" id="filesmatch">Directive</a></h2>
1375 <table class="directive">
1376 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to regular-expression matched
1378 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><FilesMatch <var>regex</var>> ... </FilesMatch></code></td></tr>
1379 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1380 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1381 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1382 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1384 <p>The <code class="directive"><FilesMatch></code> directive
1385 limits the scope of the enclosed directives by filename, just as the
1386 <code class="directive"><a href="#files"><Files></a></code> directive
1387 does. However, it accepts a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular
1388 expression</a>. For example:</p>
1390 <div class="example"><p><code>
1391 <FilesMatch "\.(gif|jpe?g|png)$">
1394 <p>would match most common Internet graphics formats.</p>
1398 <li><a href="../sections.html">How <Directory>, <Location>
1399 and <Files> sections work</a> for an explanation of how these
1400 different sections are combined when a request is received</li>
1403 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1404 <div class="directive-section"><h2><a name="ForceType" id="ForceType">ForceType</a> <a name="forcetype" id="forcetype">Directive</a></h2>
1405 <table class="directive">
1406 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be served with the specified
1407 media type in the HTTP Content-Type header field</td></tr>
1408 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ForceType <var>media-type</var>|None</code></td></tr>
1409 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
1410 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1411 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1412 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1413 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Moved to the core in Apache httpd 2.0</td></tr>
1415 <p>When placed into an <code>.htaccess</code> file or a
1416 <code class="directive"><a href="#directory"><Directory></a></code>, or
1417 <code class="directive"><a href="#location"><Location></a></code> or
1418 <code class="directive"><a href="#files"><Files></a></code>
1419 section, this directive forces all matching files to be served
1420 with the content type identification given by
1421 <var>media-type</var>. For example, if you had a directory full of
1422 GIF files, but did not want to label them all with <code>.gif</code>,
1423 you might want to use:</p>
1425 <div class="example"><p><code>
1429 <p>Note that this directive overrides other indirect media type
1430 associations defined in mime.types or via the
1431 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code>.</p>
1433 <p>You can also override more general
1434 <code class="directive">ForceType</code> settings
1435 by using the value of <code>None</code>:</p>
1437 <div class="example"><p><code>
1438 # force all files to be image/gif:<br />
1439 <Location /images><br />
1440 <span class="indent">
1441 ForceType image/gif<br />
1443 </Location><br />
1445 # but normal mime-type associations here:<br />
1446 <Location /images/mixed><br />
1447 <span class="indent">
1448 ForceType None<br />
1453 <p>This directive primarily overrides the content types generated for
1454 static files served out of the filesystem. For resources other than
1455 static files, where the generator of the response typically specifies
1456 a Content-Type, this directive has no effect.</p>
1460 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1461 <div class="directive-section"><h2><a name="HostnameLookups" id="HostnameLookups">HostnameLookups</a> <a name="hostnamelookups" id="hostnamelookups">Directive</a></h2>
1462 <table class="directive">
1463 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables DNS lookups on client IP addresses</td></tr>
1464 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>HostnameLookups On|Off|Double</code></td></tr>
1465 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>HostnameLookups Off</code></td></tr>
1466 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1467 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1468 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1470 <p>This directive enables DNS lookups so that host names can be
1471 logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
1472 The value <code>Double</code> refers to doing double-reverse
1473 DNS lookup. That is, after a reverse lookup is performed, a forward
1474 lookup is then performed on that result. At least one of the IP
1475 addresses in the forward lookup must match the original
1476 address. (In "tcpwrappers" terminology this is called
1477 <code>PARANOID</code>.)</p>
1479 <p>Regardless of the setting, when <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code> is
1480 used for controlling access by hostname, a double reverse lookup
1481 will be performed. This is necessary for security. Note that the
1482 result of this double-reverse isn't generally available unless you
1483 set <code>HostnameLookups Double</code>. For example, if only
1484 <code>HostnameLookups On</code> and a request is made to an object
1485 that is protected by hostname restrictions, regardless of whether
1486 the double-reverse fails or not, CGIs will still be passed the
1487 single-reverse result in <code>REMOTE_HOST</code>.</p>
1489 <p>The default is <code>Off</code> in order to save the network
1490 traffic for those sites that don't truly need the reverse
1491 lookups done. It is also better for the end users because they
1492 don't have to suffer the extra latency that a lookup entails.
1493 Heavily loaded sites should leave this directive
1494 <code>Off</code>, since DNS lookups can take considerable
1495 amounts of time. The utility <code class="program"><a href="../programs/logresolve.html">logresolve</a></code>, compiled by
1496 default to the <code>bin</code> subdirectory of your installation
1497 directory, can be used to look up host names from logged IP addresses
1501 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1502 <div class="directive-section"><h2><a name="If" id="If"><If></a> <a name="if" id="if">Directive</a></h2>
1503 <table class="directive">
1504 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is
1505 satisfied by a request at runtime</td></tr>
1506 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><If <var>expression</var>> ... </If></code></td></tr>
1507 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1508 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1509 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1510 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1512 <p>The <code class="directive"><If></code> directive
1513 evaluates an expression at runtime, and applies the enclosed
1514 directives if and only if the expression evaluates to true.
1517 <div class="example"><p><code>
1518 <If "$req{Host} = ''">
1521 <p>would match HTTP/1.0 requests without a <var>Host:</var> header.</p>
1523 <p>You may compare the value of any variable in the request headers
1524 ($req), response headers ($resp) or environment ($env) in your
1529 <li><a href="../sections.html">How <Directory>, <Location>,
1530 <Files> sections work</a> for an explanation of how these
1531 different sections are combined when a request is received.
1532 <code class="directive"><If></code> has the same precedence
1533 and usage as <code class="directive"><Files></code></li>
1536 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1537 <div class="directive-section"><h2><a name="IfDefine" id="IfDefine"><IfDefine></a> <a name="ifdefine" id="ifdefine">Directive</a></h2>
1538 <table class="directive">
1539 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that will be processed only
1540 if a test is true at startup</td></tr>
1541 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfDefine [!]<var>parameter-name</var>> ...
1542 </IfDefine></code></td></tr>
1543 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1544 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1545 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1546 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1548 <p>The <code><IfDefine <var>test</var>>...</IfDefine>
1549 </code> section is used to mark directives that are conditional. The
1550 directives within an <code class="directive"><IfDefine></code>
1551 section are only processed if the <var>test</var> is true. If <var>
1552 test</var> is false, everything between the start and end markers is
1555 <p>The <var>test</var> in the <code class="directive"><IfDefine></code> section directive can be one of two forms:</p>
1558 <li><var>parameter-name</var></li>
1560 <li><code>!</code><var>parameter-name</var></li>
1563 <p>In the former case, the directives between the start and end
1564 markers are only processed if the parameter named
1565 <var>parameter-name</var> is defined. The second format reverses
1566 the test, and only processes the directives if
1567 <var>parameter-name</var> is <strong>not</strong> defined.</p>
1569 <p>The <var>parameter-name</var> argument is a define as given on the
1570 <code class="program"><a href="../programs/httpd.html">httpd</a></code> command line via <code>-D<var>parameter</var>
1571 </code> at the time the server was started or by the <code class="directive"><a href="#define">Define</a></code> directive.</p>
1573 <p><code class="directive"><IfDefine></code> sections are
1574 nest-able, which can be used to implement simple
1575 multiple-parameter tests. Example:</p>
1577 <div class="example"><p><code>
1578 httpd -DReverseProxy -DUseCache -DMemCache ...<br />
1581 <IfDefine ReverseProxy><br />
1582 <span class="indent">
1583 LoadModule proxy_module modules/mod_proxy.so<br />
1584 LoadModule proxy_http_module modules/mod_proxy_http.so<br />
1585 <IfDefine UseCache><br />
1586 <span class="indent">
1587 LoadModule cache_module modules/mod_cache.so<br />
1588 <IfDefine MemCache><br />
1589 <span class="indent">
1590 LoadModule mem_cache_module modules/mod_mem_cache.so<br />
1592 </IfDefine><br />
1593 <IfDefine !MemCache><br />
1594 <span class="indent">
1595 LoadModule disk_cache_module modules/mod_disk_cache.so<br />
1605 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1606 <div class="directive-section"><h2><a name="IfModule" id="IfModule"><IfModule></a> <a name="ifmodule" id="ifmodule">Directive</a></h2>
1607 <table class="directive">
1608 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that are processed conditional on the
1609 presence or absence of a specific module</td></tr>
1610 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfModule [!]<var>module-file</var>|<var>module-identifier</var>> ...
1611 </IfModule></code></td></tr>
1612 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1613 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1614 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1615 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1616 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Module identifiers are available in version 2.1 and
1619 <p>The <code><IfModule <var>test</var>>...</IfModule></code>
1620 section is used to mark directives that are conditional on the presence of
1621 a specific module. The directives within an <code class="directive"><IfModule></code> section are only processed if the <var>test</var>
1622 is true. If <var>test</var> is false, everything between the start and
1623 end markers is ignored.</p>
1625 <p>The <var>test</var> in the <code class="directive"><IfModule></code> section directive can be one of two forms:</p>
1628 <li><var>module</var></li>
1630 <li>!<var>module</var></li>
1633 <p>In the former case, the directives between the start and end
1634 markers are only processed if the module named <var>module</var>
1635 is included in Apache httpd -- either compiled in or
1636 dynamically loaded using <code class="directive"><a href="../mod/mod_so.html#loadmodule">LoadModule</a></code>. The second format reverses the test,
1637 and only processes the directives if <var>module</var> is
1638 <strong>not</strong> included.</p>
1640 <p>The <var>module</var> argument can be either the module identifier or
1641 the file name of the module, at the time it was compiled. For example,
1642 <code>rewrite_module</code> is the identifier and
1643 <code>mod_rewrite.c</code> is the file name. If a module consists of
1644 several source files, use the name of the file containing the string
1645 <code>STANDARD20_MODULE_STUFF</code>.</p>
1647 <p><code class="directive"><IfModule></code> sections are
1648 nest-able, which can be used to implement simple multiple-module
1651 <div class="note">This section should only be used if you need to have one
1652 configuration file that works whether or not a specific module
1653 is available. In normal operation, directives need not be
1654 placed in <code class="directive"><IfModule></code>
1658 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1659 <div class="directive-section"><h2><a name="Include" id="Include">Include</a> <a name="include" id="include">Directive</a></h2>
1660 <table class="directive">
1661 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
1662 the server configuration files</td></tr>
1663 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Include [<var>optional</var>|<var>strict</var>] <var>file-path</var>|<var>directory-path</var>|<var>wildcard</var></code></td></tr>
1664 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1665 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1666 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1667 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Wildcard matching available in 2.0.41 and later, directory
1668 wildcard matching available in 2.3.6 and later</td></tr>
1670 <p>This directive allows inclusion of other configuration files
1671 from within the server configuration files.</p>
1673 <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used
1674 in the filename or directory parts of the path to include several files
1675 at once, in alphabetical order. In addition, if
1676 <code class="directive">Include</code> points to a directory, rather than a file,
1677 Apache httpd will read all files in that directory and any subdirectory.
1678 However, including entire directories is not recommended, because it is
1679 easy to accidentally leave temporary files in a directory that can cause
1680 <code class="program"><a href="../programs/httpd.html">httpd</a></code> to fail. Instead, we encourage you to use the
1681 wildcard syntax shown below, to include files that match a particular
1682 pattern, such as *.conf, for example.</p>
1684 <p>When a wildcard is specified for a <strong>file</strong> component of
1685 the path, and no file matches the wildcard, the
1686 <code class="directive"><a href="#include">Include</a></code>
1687 directive will be <strong>silently ignored</strong>. When a wildcard is
1688 specified for a <strong>directory</strong> component of the path, and
1689 no directory matches the wildcard, the
1690 <code class="directive"><a href="#include">Include</a></code> directive will
1691 <strong>fail with an error</strong> saying the directory cannot be found.
1694 <p>For further control over the behaviour of the server when no files or
1695 directories match, prefix the path with the modifiers <var>optional</var>
1696 or <var>strict</var>. If <var>optional</var> is specified, any wildcard
1697 file or directory that does not match will be silently ignored. If
1698 <var>strict</var> is specified, any wildcard file or directory that does
1699 not match at least one file will cause server startup to fail.</p>
1701 <p>When a directory or file component of the path is
1702 specified exactly, and that directory or file does not exist,
1703 <code class="directive"><a href="#include">Include</a></code> directive will fail with an
1704 error saying the file or directory cannot be found.</p>
1706 <p>The file path specified may be an absolute path, or may be relative
1707 to the <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory.</p>
1711 <div class="example"><p><code>
1712 Include /usr/local/apache2/conf/ssl.conf<br />
1713 Include /usr/local/apache2/conf/vhosts/*.conf
1716 <p>Or, providing paths relative to your <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory:</p>
1718 <div class="example"><p><code>
1719 Include conf/ssl.conf<br />
1720 Include conf/vhosts/*.conf
1723 <p>Wildcards may be included in the directory or file portion of the
1724 path. In the following example, the server will fail to load if no
1725 directories match conf/vhosts/*, but will load successfully if no
1726 files match *.conf.</p>
1728 <div class="example"><p><code>
1729 Include conf/vhosts/*/vhost.conf<br />
1730 Include conf/vhosts/*/*.conf
1733 <p>In this example, the server will fail to load if either
1734 conf/vhosts/* matches no directories, or if *.conf matches no files:</p>
1736 <div class="example"><p><code>
1737 Include strict conf/vhosts/*/*.conf
1740 <p>In this example, the server load successfully if either conf/vhosts/*
1741 matches no directories, or if *.conf matches no files:</p>
1743 <div class="example"><p><code>
1744 Include optional conf/vhosts/*/*.conf
1750 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
1753 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1754 <div class="directive-section"><h2><a name="KeepAlive" id="KeepAlive">KeepAlive</a> <a name="keepalive" id="keepalive">Directive</a></h2>
1755 <table class="directive">
1756 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables HTTP persistent connections</td></tr>
1757 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAlive On|Off</code></td></tr>
1758 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAlive On</code></td></tr>
1759 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1760 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1761 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1763 <p>The Keep-Alive extension to HTTP/1.0 and the persistent
1764 connection feature of HTTP/1.1 provide long-lived HTTP sessions
1765 which allow multiple requests to be sent over the same TCP
1766 connection. In some cases this has been shown to result in an
1767 almost 50% speedup in latency times for HTML documents with
1768 many images. To enable Keep-Alive connections, set
1769 <code>KeepAlive On</code>.</p>
1771 <p>For HTTP/1.0 clients, Keep-Alive connections will only be
1772 used if they are specifically requested by a client. In
1773 addition, a Keep-Alive connection with an HTTP/1.0 client can
1774 only be used when the length of the content is known in
1775 advance. This implies that dynamic content such as CGI output,
1776 SSI pages, and server-generated directory listings will
1777 generally not use Keep-Alive connections to HTTP/1.0 clients.
1778 For HTTP/1.1 clients, persistent connections are the default
1779 unless otherwise specified. If the client requests it, chunked
1780 encoding will be used in order to send content of unknown
1781 length over persistent connections.</p>
1783 <p>When a client uses a Keep-Alive connection it will be counted
1784 as a single "request" for the <code class="directive"><a href="../mod/mpm_common.html#maxrequestsperchild">MaxRequestsPerChild</a></code> directive, regardless
1785 of how many requests are sent using the connection.</p>
1789 <li><code class="directive"><a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></code></li>
1792 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1793 <div class="directive-section"><h2><a name="KeepAliveTimeout" id="KeepAliveTimeout">KeepAliveTimeout</a> <a name="keepalivetimeout" id="keepalivetimeout">Directive</a></h2>
1794 <table class="directive">
1795 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for subsequent
1796 requests on a persistent connection</td></tr>
1797 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAliveTimeout <var>num</var>[ms]</code></td></tr>
1798 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAliveTimeout 5</code></td></tr>
1799 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1800 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1801 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1802 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Specifying a value in milliseconds is available in
1803 Apache httpd 2.3.2 and later</td></tr>
1805 <p>The number of seconds Apache httpd will wait for a subsequent
1806 request before closing the connection. By adding a postfix of ms the
1807 timeout can be also set in milliseconds. Once a request has been
1808 received, the timeout value specified by the
1809 <code class="directive"><a href="#timeout">Timeout</a></code> directive applies.</p>
1811 <p>Setting <code class="directive">KeepAliveTimeout</code> to a high value
1812 may cause performance problems in heavily loaded servers. The
1813 higher the timeout, the more server processes will be kept
1814 occupied waiting on connections with idle clients.</p>
1816 <p>In a name-based virtual host context, the value of the first
1817 defined virtual host (the default host) in a set of <code class="directive"><a href="#namevirtualhost">NameVirtualHost</a></code> will be used.
1818 The other values will be ignored.</p>
1821 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1822 <div class="directive-section"><h2><a name="Limit" id="Limit"><Limit></a> <a name="limit" id="limit">Directive</a></h2>
1823 <table class="directive">
1824 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict enclosed access controls to only certain HTTP
1826 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Limit <var>method</var> [<var>method</var>] ... > ...
1827 </Limit></code></td></tr>
1828 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
1829 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
1830 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1831 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1833 <p>Access controls are normally effective for
1834 <strong>all</strong> access methods, and this is the usual
1835 desired behavior. <strong>In the general case, access control
1836 directives should not be placed within a
1837 <code class="directive"><Limit></code> section.</strong></p>
1839 <p>The purpose of the <code class="directive"><Limit></code>
1840 directive is to restrict the effect of the access controls to the
1841 nominated HTTP methods. For all other methods, the access
1842 restrictions that are enclosed in the <code class="directive"><Limit></code> bracket <strong>will have no
1843 effect</strong>. The following example applies the access control
1844 only to the methods <code>POST</code>, <code>PUT</code>, and
1845 <code>DELETE</code>, leaving all other methods unprotected:</p>
1847 <div class="example"><p><code>
1848 <Limit POST PUT DELETE><br />
1849 <span class="indent">
1850 Require valid-user<br />
1855 <p>The method names listed can be one or more of: <code>GET</code>,
1856 <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
1857 <code>CONNECT</code>, <code>OPTIONS</code>,
1858 <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
1859 <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
1860 <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
1861 case-sensitive.</strong> If <code>GET</code> is used it will also
1862 restrict <code>HEAD</code> requests. The <code>TRACE</code> method
1863 cannot be limited (see <code class="directive"><a href="#traceenable">TraceEnable</a></code>).</p>
1865 <div class="warning">A <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section should always be
1866 used in preference to a <code class="directive"><Limit></code>
1867 section when restricting access, since a <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section provides protection
1868 against arbitrary methods.</div>
1870 <p>The <code class="directive"><Limit></code> and
1871 <code class="directive"><a href="#limitexcept"><LimitExcept></a></code>
1872 directives may be nested. In this case, each successive level of
1873 <code class="directive"><Limit></code> or <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> directives must
1874 further restrict the set of methods to which access controls apply.</p>
1876 <div class="warning">When using
1877 <code class="directive"><Limit></code> or
1878 <code class="directive"><LimitExcept></code> directives with
1879 the <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directive,
1880 note that the first <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code>
1881 to succeed authorizes the request, regardless of the presence of other
1882 <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directives.</div>
1884 <p>For example, given the following configuration, all users will
1885 be authorized for <code>POST</code> requests, and the
1886 <code>Require group editors</code> directive will be ignored
1889 <div class="example"><p><code>
1890 <LimitExcept GET>
1891 <span class="indent">
1894 </LimitExcept><br />
1896 <span class="indent">
1897 Require group editors
1903 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1904 <div class="directive-section"><h2><a name="LimitExcept" id="LimitExcept"><LimitExcept></a> <a name="limitexcept" id="limitexcept">Directive</a></h2>
1905 <table class="directive">
1906 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict access controls to all HTTP methods
1907 except the named ones</td></tr>
1908 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LimitExcept <var>method</var> [<var>method</var>] ... > ...
1909 </LimitExcept></code></td></tr>
1910 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
1911 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
1912 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1913 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1915 <p><code class="directive"><LimitExcept></code> and
1916 <code></LimitExcept></code> are used to enclose
1917 a group of access control directives which will then apply to any
1918 HTTP access method <strong>not</strong> listed in the arguments;
1919 i.e., it is the opposite of a <code class="directive"><a href="#limit"><Limit></a></code> section and can be used to control
1920 both standard and nonstandard/unrecognized methods. See the
1921 documentation for <code class="directive"><a href="#limit"><Limit></a></code> for more details.</p>
1925 <div class="example"><p><code>
1926 <LimitExcept POST GET><br />
1927 <span class="indent">
1928 Require valid-user<br />
1930 </LimitExcept>
1935 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1936 <div class="directive-section"><h2><a name="LimitInternalRecursion" id="LimitInternalRecursion">LimitInternalRecursion</a> <a name="limitinternalrecursion" id="limitinternalrecursion">Directive</a></h2>
1937 <table class="directive">
1938 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine maximum number of internal redirects and nested
1939 subrequests</td></tr>
1940 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitInternalRecursion <var>number</var> [<var>number</var>]</code></td></tr>
1941 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitInternalRecursion 10</code></td></tr>
1942 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1943 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1944 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1945 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.0.47 and later</td></tr>
1947 <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
1948 redirects the original request to a CGI script. A subrequest is Apache httpd's
1949 mechanism to find out what would happen for some URI if it were requested.
1950 For example, <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> uses subrequests to look for the
1951 files listed in the <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
1954 <p><code class="directive">LimitInternalRecursion</code> prevents the server
1955 from crashing when entering an infinite loop of internal redirects or
1956 subrequests. Such loops are usually caused by misconfigurations.</p>
1958 <p>The directive stores two different limits, which are evaluated on
1959 per-request basis. The first <var>number</var> is the maximum number of
1960 internal redirects, that may follow each other. The second <var>number</var>
1961 determines, how deep subrequests may be nested. If you specify only one
1962 <var>number</var>, it will be assigned to both limits.</p>
1964 <div class="example"><h3>Example</h3><p><code>
1965 LimitInternalRecursion 5
1969 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1970 <div class="directive-section"><h2><a name="LimitRequestBody" id="LimitRequestBody">LimitRequestBody</a> <a name="limitrequestbody" id="limitrequestbody">Directive</a></h2>
1971 <table class="directive">
1972 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restricts the total size of the HTTP request body sent
1973 from the client</td></tr>
1974 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestBody <var>bytes</var></code></td></tr>
1975 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestBody 0</code></td></tr>
1976 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1977 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1978 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1979 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1981 <p>This directive specifies the number of <var>bytes</var> from 0
1982 (meaning unlimited) to 2147483647 (2GB) that are allowed in a
1985 <p>The <code class="directive">LimitRequestBody</code> directive allows
1986 the user to set a limit on the allowed size of an HTTP request
1987 message body within the context in which the directive is given
1988 (server, per-directory, per-file or per-location). If the client
1989 request exceeds that limit, the server will return an error
1990 response instead of servicing the request. The size of a normal
1991 request message body will vary greatly depending on the nature of
1992 the resource and the methods allowed on that resource. CGI scripts
1993 typically use the message body for retrieving form information.
1994 Implementations of the <code>PUT</code> method will require
1995 a value at least as large as any representation that the server
1996 wishes to accept for that resource.</p>
1998 <p>This directive gives the server administrator greater
1999 control over abnormal client request behavior, which may be
2000 useful for avoiding some forms of denial-of-service
2003 <p>If, for example, you are permitting file upload to a particular
2004 location, and wish to limit the size of the uploaded file to 100K,
2005 you might use the following directive:</p>
2007 <div class="example"><p><code>
2008 LimitRequestBody 102400
2013 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2014 <div class="directive-section"><h2><a name="LimitRequestFields" id="LimitRequestFields">LimitRequestFields</a> <a name="limitrequestfields" id="limitrequestfields">Directive</a></h2>
2015 <table class="directive">
2016 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of HTTP request header fields that
2017 will be accepted from the client</td></tr>
2018 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFields <var>number</var></code></td></tr>
2019 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFields 100</code></td></tr>
2020 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
2021 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2022 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2024 <p><var>Number</var> is an integer from 0 (meaning unlimited) to
2025 32767. The default value is defined by the compile-time
2026 constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
2029 <p>The <code class="directive">LimitRequestFields</code> directive allows
2030 the server administrator to modify the limit on the number of
2031 request header fields allowed in an HTTP request. A server needs
2032 this value to be larger than the number of fields that a normal
2033 client request might include. The number of request header fields
2034 used by a client rarely exceeds 20, but this may vary among
2035 different client implementations, often depending upon the extent
2036 to which a user has configured their browser to support detailed
2037 content negotiation. Optional HTTP extensions are often expressed
2038 using request header fields.</p>
2040 <p>This directive gives the server administrator greater
2041 control over abnormal client request behavior, which may be
2042 useful for avoiding some forms of denial-of-service attacks.
2043 The value should be increased if normal clients see an error
2044 response from the server that indicates too many fields were
2045 sent in the request.</p>
2049 <div class="example"><p><code>
2050 LimitRequestFields 50
2055 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2056 <div class="directive-section"><h2><a name="LimitRequestFieldSize" id="LimitRequestFieldSize">LimitRequestFieldSize</a> <a name="limitrequestfieldsize" id="limitrequestfieldsize">Directive</a></h2>
2057 <table class="directive">
2058 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of the HTTP request header allowed from the
2060 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFieldSize <var>bytes</var></code></td></tr>
2061 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFieldSize 8190</code></td></tr>
2062 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
2063 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2064 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2066 <p>This directive specifies the number of <var>bytes</var>
2067 that will be allowed in an HTTP request header.</p>
2069 <p>The <code class="directive">LimitRequestFieldSize</code> directive
2070 allows the server administrator to reduce or increase the limit
2071 on the allowed size of an HTTP request header field. A server
2072 needs this value to be large enough to hold any one header field
2073 from a normal client request. The size of a normal request header
2074 field will vary greatly among different client implementations,
2075 often depending upon the extent to which a user has configured
2076 their browser to support detailed content negotiation. SPNEGO
2077 authentication headers can be up to 12392 bytes.</p>
2079 <p>This directive gives the server administrator greater
2080 control over abnormal client request behavior, which may be
2081 useful for avoiding some forms of denial-of-service attacks.</p>
2085 <div class="example"><p><code>
2086 LimitRequestFieldSize 4094
2089 <div class="note">Under normal conditions, the value should not be changed from
2094 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2095 <div class="directive-section"><h2><a name="LimitRequestLine" id="LimitRequestLine">LimitRequestLine</a> <a name="limitrequestline" id="limitrequestline">Directive</a></h2>
2096 <table class="directive">
2097 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limit the size of the HTTP request line that will be accepted
2098 from the client</td></tr>
2099 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestLine <var>bytes</var></code></td></tr>
2100 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestLine 8190</code></td></tr>
2101 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
2102 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2103 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2105 <p>This directive sets the number of <var>bytes</var> that will be
2106 allowed on the HTTP request-line.</p>
2108 <p>The <code class="directive">LimitRequestLine</code> directive allows
2109 the server administrator to reduce or increase the limit on the allowed size
2110 of a client's HTTP request-line. Since the request-line consists of the
2111 HTTP method, URI, and protocol version, the
2112 <code class="directive">LimitRequestLine</code> directive places a
2113 restriction on the length of a request-URI allowed for a request
2114 on the server. A server needs this value to be large enough to
2115 hold any of its resource names, including any information that
2116 might be passed in the query part of a <code>GET</code> request.</p>
2118 <p>This directive gives the server administrator greater
2119 control over abnormal client request behavior, which may be
2120 useful for avoiding some forms of denial-of-service attacks.</p>
2124 <div class="example"><p><code>
2125 LimitRequestLine 4094
2128 <div class="note">Under normal conditions, the value should not be changed from
2132 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2133 <div class="directive-section"><h2><a name="LimitXMLRequestBody" id="LimitXMLRequestBody">LimitXMLRequestBody</a> <a name="limitxmlrequestbody" id="limitxmlrequestbody">Directive</a></h2>
2134 <table class="directive">
2135 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of an XML-based request body</td></tr>
2136 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitXMLRequestBody <var>bytes</var></code></td></tr>
2137 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitXMLRequestBody 1000000</code></td></tr>
2138 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2139 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2140 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2141 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2143 <p>Limit (in bytes) on maximum size of an XML-based request
2144 body. A value of <code>0</code> will disable any checking.</p>
2148 <div class="example"><p><code>
2149 LimitXMLRequestBody 0
2154 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2155 <div class="directive-section"><h2><a name="Location" id="Location"><Location></a> <a name="location" id="location">Directive</a></h2>
2156 <table class="directive">
2157 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to matching
2159 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Location
2160 <var>URL-path</var>|<var>URL</var>> ... </Location></code></td></tr>
2161 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2162 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2163 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2165 <p>The <code class="directive"><Location></code> directive
2166 limits the scope of the enclosed directives by URL. It is similar to the
2167 <code class="directive"><a href="#directory"><Directory></a></code>
2168 directive, and starts a subsection which is terminated with a
2169 <code></Location></code> directive. <code class="directive"><Location></code> sections are processed in the
2170 order they appear in the configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
2171 <code>.htaccess</code> files are read, and after the <code class="directive"><a href="#files"><Files></a></code> sections.</p>
2173 <p><code class="directive"><Location></code> sections operate
2174 completely outside the filesystem. This has several consequences.
2175 Most importantly, <code class="directive"><Location></code>
2176 directives should not be used to control access to filesystem
2177 locations. Since several different URLs may map to the same
2178 filesystem location, such access controls may by circumvented.</p>
2180 <div class="note"><h3>When to use <code class="directive"><Location></code></h3>
2182 <p>Use <code class="directive"><Location></code> to apply
2183 directives to content that lives outside the filesystem. For
2184 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
2185 <code><Location /></code>, which is an easy way to
2186 apply a configuration to the entire server.</p>
2189 <p>For all origin (non-proxy) requests, the URL to be matched is a
2190 URL-path of the form <code>/path/</code>. <em>No scheme, hostname,
2191 port, or query string may be included.</em> For proxy requests, the
2192 URL to be matched is of the form
2193 <code>scheme://servername/path</code>, and you must include the
2196 <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
2197 any single character, and <code>*</code> matches any sequences of
2198 characters. Neither wildcard character matches a / in the URL-path.</p>
2200 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
2201 can also be used, with the addition of the <code>~</code>
2202 character. For example:</p>
2204 <div class="example"><p><code>
2205 <Location ~ "/(extra|special)/data">
2208 <p>would match URLs that contained the substring <code>/extra/data</code>
2209 or <code>/special/data</code>. The directive <code class="directive"><a href="#locationmatch"><LocationMatch></a></code> behaves
2210 identical to the regex version of <code class="directive"><Location></code>, and is preferred, for the
2211 simple reason that <code>~</code> is hard to distinguish from
2212 <code>-</code> in many fonts.</p>
2214 <p>The <code class="directive"><Location></code>
2215 functionality is especially useful when combined with the
2216 <code class="directive"><a href="#sethandler">SetHandler</a></code>
2217 directive. For example, to enable status requests, but allow them
2218 only from browsers at <code>example.com</code>, you might use:</p>
2220 <div class="example"><p><code>
2221 <Location /status><br />
2222 <span class="indent">
2223 SetHandler server-status<br />
2224 Order Deny,Allow<br />
2226 Allow from .example.com<br />
2231 <div class="note"><h3>Note about / (slash)</h3>
2232 <p>The slash character has special meaning depending on where in a
2233 URL it appears. People may be used to its behavior in the filesystem
2234 where multiple adjacent slashes are frequently collapsed to a single
2235 slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
2236 <code>/home/foo</code>). In URL-space this is not necessarily true.
2237 The <code class="directive"><a href="#locationmatch"><LocationMatch></a></code>
2238 directive and the regex version of <code class="directive"><Location></code> require you to explicitly specify multiple
2239 slashes if that is your intention.</p>
2241 <p>For example, <code><LocationMatch ^/abc></code> would match
2242 the request URL <code>/abc</code> but not the request URL <code>
2243 //abc</code>. The (non-regex) <code class="directive"><Location></code> directive behaves similarly when used for
2244 proxy requests. But when (non-regex) <code class="directive"><Location></code> is used for non-proxy requests it will
2245 implicitly match multiple slashes with a single slash. For example,
2246 if you specify <code><Location /abc/def></code> and the
2247 request is to <code>/abc//def</code> then it will match.</p>
2252 <li><a href="../sections.html">How <Directory>, <Location>
2253 and <Files> sections work</a> for an explanation of how these
2254 different sections are combined when a request is received.</li>
2255 <li><code class="directive"><a href="#locationmatch">LocationMatch</a></code></li>
2258 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2259 <div class="directive-section"><h2><a name="LocationMatch" id="LocationMatch"><LocationMatch></a> <a name="locationmatch" id="locationmatch">Directive</a></h2>
2260 <table class="directive">
2261 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to regular-expression
2262 matching URLs</td></tr>
2263 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LocationMatch
2264 <var>regex</var>> ... </LocationMatch></code></td></tr>
2265 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2266 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2267 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2269 <p>The <code class="directive"><LocationMatch></code> directive
2270 limits the scope of the enclosed directives by URL, in an identical manner
2271 to <code class="directive"><a href="#location"><Location></a></code>. However,
2272 it takes a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
2273 as an argument instead of a simple string. For example:</p>
2275 <div class="example"><p><code>
2276 <LocationMatch "/(extra|special)/data">
2279 <p>would match URLs that contained the substring <code>/extra/data</code>
2280 or <code>/special/data</code>.</p>
2284 <li><a href="../sections.html">How <Directory>, <Location>
2285 and <Files> sections work</a> for an explanation of how these
2286 different sections are combined when a request is received</li>
2289 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2290 <div class="directive-section"><h2><a name="LogLevel" id="LogLevel">LogLevel</a> <a name="loglevel" id="loglevel">Directive</a></h2>
2291 <table class="directive">
2292 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Controls the verbosity of the ErrorLog</td></tr>
2293 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel [<var>module</var>:]<var>level</var>
2294 [<var>module</var>:<var>level</var>] ...
2296 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LogLevel warn</code></td></tr>
2297 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2298 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2299 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2300 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Per-module and per-directory configuration is available in
2301 Apache HTTP Server 2.3.6 and later</td></tr>
2303 <p><code class="directive">LogLevel</code> adjusts the verbosity of the
2304 messages recorded in the error logs (see <code class="directive"><a href="#errorlog">ErrorLog</a></code> directive). The following
2305 <var>level</var>s are available, in order of decreasing
2308 <table class="bordered">
2311 <th><strong>Level</strong> </th>
2313 <th><strong>Description</strong> </th>
2315 <th><strong>Example</strong> </th>
2319 <td><code>emerg</code> </td>
2321 <td>Emergencies - system is unusable.</td>
2323 <td>"Child cannot open lock file. Exiting"</td>
2327 <td><code>alert</code> </td>
2329 <td>Action must be taken immediately.</td>
2331 <td>"getpwuid: couldn't determine user name from uid"</td>
2335 <td><code>crit</code> </td>
2337 <td>Critical Conditions.</td>
2339 <td>"socket: Failed to get a socket, exiting child"</td>
2343 <td><code>error</code> </td>
2345 <td>Error conditions.</td>
2347 <td>"Premature end of script headers"</td>
2351 <td><code>warn</code> </td>
2353 <td>Warning conditions.</td>
2355 <td>"child process 1234 did not exit, sending another
2360 <td><code>notice</code> </td>
2362 <td>Normal but significant condition.</td>
2364 <td>"httpd: caught SIGBUS, attempting to dump core in
2369 <td><code>info</code> </td>
2371 <td>Informational.</td>
2373 <td>"Server seems busy, (you may need to increase
2374 StartServers, or Min/MaxSpareServers)..."</td>
2378 <td><code>debug</code> </td>
2380 <td>Debug-level messages</td>
2382 <td>"Opening config file ..."</td>
2385 <td><code>trace1</code> </td>
2387 <td>Trace messages</td>
2389 <td>"proxy: FTP: control connection complete"</td>
2392 <td><code>trace2</code> </td>
2394 <td>Trace messages</td>
2396 <td>"proxy: CONNECT: sending the CONNECT request to the remote proxy"</td>
2399 <td><code>trace3</code> </td>
2401 <td>Trace messages</td>
2403 <td>"openssl: Handshake: start"</td>
2406 <td><code>trace4</code> </td>
2408 <td>Trace messages</td>
2410 <td>"read from buffered SSL brigade, mode 0, 17 bytes"</td>
2413 <td><code>trace5</code> </td>
2415 <td>Trace messages</td>
2417 <td>"map lookup FAILED: map=rewritemap key=keyname"</td>
2420 <td><code>trace6</code> </td>
2422 <td>Trace messages</td>
2424 <td>"cache lookup FAILED, forcing new map lookup"</td>
2427 <td><code>trace7</code> </td>
2429 <td>Trace messages, dumping large amounts of data</td>
2431 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2434 <td><code>trace8</code> </td>
2436 <td>Trace messages, dumping large amounts of data</td>
2438 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2442 <p>When a particular level is specified, messages from all
2443 other levels of higher significance will be reported as well.
2444 <em>E.g.</em>, when <code>LogLevel info</code> is specified,
2445 then messages with log levels of <code>notice</code> and
2446 <code>warn</code> will also be posted.</p>
2448 <p>Using a level of at least <code>crit</code> is
2453 <div class="example"><p><code>
2457 <div class="note"><h3>Note</h3>
2458 <p>When logging to a regular file messages of the level
2459 <code>notice</code> cannot be suppressed and thus are always
2460 logged. However, this doesn't apply when logging is done
2461 using <code>syslog</code>.</p>
2464 <p>Specifying a level without a module name will reset the level
2465 for all modules to that level. Specifying a level with a module
2466 name will set the level for that module only. It is possible to
2467 use the module source file name, the module identifier, or the
2468 module identifier with the trailing <code>_module</code> omitted
2469 as module specification. This means the following three specifications
2472 <div class="example"><p><code>
2473 LogLevel info ssl:warn<br />
2474 LogLevel info mod_ssl.c:warn<br />
2475 LogLevel info ssl_module:warn<br />
2478 <p>It is also possible to change the level per directory:</p>
2480 <div class="example"><p><code>
2482 <Directory /usr/local/apache/htdocs/app><br />
2483 LogLevel debug<br />
2488 Per directory loglevel configuration only affects messages that are
2489 logged after the request has been parsed and that are associated with
2490 the request. Log messages which are associated with the connection or
2491 the server are not affected.
2495 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2496 <div class="directive-section"><h2><a name="MaxKeepAliveRequests" id="MaxKeepAliveRequests">MaxKeepAliveRequests</a> <a name="maxkeepaliverequests" id="maxkeepaliverequests">Directive</a></h2>
2497 <table class="directive">
2498 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of requests allowed on a persistent
2499 connection</td></tr>
2500 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxKeepAliveRequests <var>number</var></code></td></tr>
2501 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxKeepAliveRequests 100</code></td></tr>
2502 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2503 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2504 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2506 <p>The <code class="directive">MaxKeepAliveRequests</code> directive
2507 limits the number of requests allowed per connection when
2508 <code class="directive"><a href="#keepalive">KeepAlive</a></code> is on. If it is
2509 set to <code>0</code>, unlimited requests will be allowed. We
2510 recommend that this setting be kept to a high value for maximum
2511 server performance.</p>
2515 <div class="example"><p><code>
2516 MaxKeepAliveRequests 500
2520 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2521 <div class="directive-section"><h2><a name="Mutex" id="Mutex">Mutex</a> <a name="mutex" id="mutex">Directive</a></h2>
2522 <table class="directive">
2523 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures mutex mechanism and lock file directory for all
2524 or specified mutexes</td></tr>
2525 <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>
2526 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Mutex default</code></td></tr>
2527 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
2528 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2529 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2530 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.4 and later</td></tr>
2532 <p>The <code class="directive">Mutex</code> directive sets the mechanism,
2533 and optionally the lock file location, that httpd and modules use
2534 to serialize access to resources. Specify <code>default</code> as
2535 the first argument to change the settings for all mutexes; specify
2536 a mutex name (see table below) as the first argument to override
2537 defaults only for that mutex.</p>
2539 <p>The <code class="directive">Mutex</code> directive is typically used in
2540 the following exceptional situations:</p>
2543 <li>change the mutex mechanism when the default mechanism selected
2544 by <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> has a functional or performance
2547 <li>change the directory used by file-based mutexes when the
2548 default directory does not support locking</li>
2551 <div class="note"><h3>Supported modules</h3>
2552 <p>This directive only configures mutexes which have been registered
2553 with the core server using the <code>ap_mutex_register()</code> API.
2554 All modules bundled with httpd support the <code class="directive">Mutex</code>
2555 directive, but third-party modules may not. Consult the documentation
2556 of the third-party module, which must indicate the mutex name(s) which
2557 can be configured if this directive is supported.</p>
2560 <p>The following mutex <em>mechanisms</em> are available:</p>
2562 <li><code>default | yes</code>
2563 <p>This selects the default locking implementation, as determined by
2564 <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a>. The default locking implementation can
2565 be displayed by running <code class="program"><a href="../programs/httpd.html">httpd</a></code> with the
2566 <code>-V</code> option.</p></li>
2568 <li><code>none | no</code>
2569 <p>This effectively disables the mutex, and is only allowed for a
2570 mutex if the module indicates that it is a valid choice. Consult the
2571 module documentation for more information.</p></li>
2573 <li><code>posixsem</code>
2574 <p>This is a mutex variant based on a Posix semaphore.</p>
2576 <div class="warning"><h3>Warning</h3>
2577 <p>The semaphore ownership is not recovered if a thread in the process
2578 holding the mutex segfaults, resulting in a hang of the web server.</p>
2582 <li><code>sysvsem</code>
2583 <p>This is a mutex variant based on a SystemV IPC semaphore.</p>
2585 <div class="warning"><h3>Warning</h3>
2586 <p>It is possible to "leak" SysV semaphores if processes crash
2587 before the semaphore is removed.</p>
2590 <div class="warning"><h3>Security</h3>
2591 <p>The semaphore API allows for a denial of service attack by any
2592 CGIs running under the same uid as the webserver (<em>i.e.</em>,
2593 all CGIs, unless you use something like <code class="program"><a href="../programs/suexec.html">suexec</a></code>
2594 or <code>cgiwrapper</code>).</p>
2598 <li><code>sem</code>
2599 <p>This selects the "best" available semaphore implementation, choosing
2600 between Posix and SystemV IPC semaphores, in that order.</p></li>
2602 <li><code>pthread</code>
2603 <p>This is a mutex variant based on cross-process Posix thread
2606 <div class="warning"><h3>Warning</h3>
2607 <p>On most systems, if a child process terminates abnormally while
2608 holding a mutex that uses this implementation, the server will deadlock
2609 and stop responding to requests. When this occurs, the server will
2610 require a manual restart to recover.</p>
2611 <p>Solaris is a notable exception as it provides a mechanism which
2612 usually allows the mutex to be recovered after a child process
2613 terminates abnormally while holding a mutex.</p>
2614 <p>If your system implements the
2615 <code>pthread_mutexattr_setrobust_np()</code> function, you may be able
2616 to use the <code>pthread</code> option safely.</p>
2620 <li><code>fcntl:/path/to/mutex</code>
2621 <p>This is a mutex variant where a physical (lock-)file and the
2622 <code>fcntl()</code> function are used as the mutex.</p>
2624 <div class="warning"><h3>Warning</h3>
2625 <p>When multiple mutexes based on this mechanism are used within
2626 multi-threaded, multi-process environments, deadlock errors (EDEADLK)
2627 can be reported for valid mutex operations if <code>fcntl()</code>
2628 is not thread-aware, such as on Solaris.</p>
2632 <li><code>flock:/path/to/mutex</code>
2633 <p>This is similar to the <code>fcntl:/path/to/mutex</code> method
2634 with the exception that the <code>flock()</code> function is used to
2635 provide file locking.</p></li>
2637 <li><code>file:/path/to/mutex</code>
2638 <p>This selects the "best" available file locking implementation,
2639 choosing between <code>fcntl</code> and <code>flock</code>, in that
2643 <p>Most mechanisms are only available on selected platforms, where the
2644 underlying platform and <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> support it. Mechanisms
2645 which aren't available on all platforms are <em>posixsem</em>,
2646 <em>sysvsem</em>, <em>sem</em>, <em>pthread</em>, <em>fcntl</em>,
2647 <em>flock</em>, and <em>file</em>.</p>
2649 <p>With the file-based mechanisms <em>fcntl</em> and <em>flock</em>,
2650 the path, if provided, is a directory where the lock file will be created.
2651 The default directory is httpd's run-time file directory relative to
2652 <code class="directive"><a href="#serverroot">ServerRoot</a></code>. Always use a local disk
2653 filesystem for <code>/path/to/mutex</code> and never a directory residing
2654 on a NFS- or AFS-filesystem. The basename of the file will be the mutex
2655 type, an optional instance string provided by the module, and unless the
2656 <code>OmitPID</code> keyword is specified, the process id of the httpd
2657 parent process will be appended to to make the file name unique, avoiding
2658 conflicts when multiple httpd instances share a lock file directory. For
2659 example, if the mutex name is <code>mpm-accept</code> and the lock file
2660 directory is <code>/var/httpd/locks</code>, the lock file name for the
2661 httpd instance with parent process id 12345 would be
2662 <code>/var/httpd/locks/mpm-accept.12345</code>.</p>
2664 <div class="warning"><h3>Security</h3>
2665 <p>It is best to <em>avoid</em> putting mutex files in a world-writable
2666 directory such as <code>/var/tmp</code> because someone could create
2667 a denial of service attack and prevent the server from starting by
2668 creating a lockfile with the same name as the one the server will try
2672 <p>The following table documents the names of mutexes used by httpd
2673 and bundled modules.</p>
2675 <table class="bordered"><tr class="header">
2678 <th>Protected resource</th>
2681 <td><code>mpm-accept</code></td>
2682 <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>
2683 <td>incoming connections, to avoid the thundering herd problem;
2684 for more information, refer to the
2685 <a href="../misc/perf-tuning.html">performance tuning</a>
2689 <td><code>authdigest-client</code></td>
2690 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
2691 <td>client list in shared memory</td>
2694 <td><code>authdigest-opaque</code></td>
2695 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
2696 <td>counter in shared memory</td>
2699 <td><code>ldap-cache</code></td>
2700 <td><code class="module"><a href="../mod/mod_ldap.html">mod_ldap</a></code></td>
2701 <td>LDAP result cache</td>
2704 <td><code>rewrite-map</code></td>
2705 <td><code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code></td>
2706 <td>communication with external mapping programs, to avoid
2707 intermixed I/O from multiple requests</td>
2710 <td><code>ssl-cache</code></td>
2711 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
2712 <td>SSL session cache</td>
2715 <td><code>ssl-stapling</code></td>
2716 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
2717 <td>OCSP stapling response cache</td>
2720 <td><code>watchdog-callback</code></td>
2721 <td><code class="module"><a href="../mod/mod_watchdog.html">mod_watchdog</a></code></td>
2722 <td>callback function of a particular client module</td>
2726 <p>The <code>OmitPID</code> keyword suppresses the addition of the httpd
2727 parent process id from the lock file name.</p>
2729 <p>In the following example, the mutex mechanism for the MPM accept
2730 mutex will be changed from the compiled-in default to <code>fcntl</code>,
2731 with the associated lock file created in directory
2732 <code>/var/httpd/locks</code>. The mutex mechanism for all other mutexes
2733 will be changed from the compiled-in default to <code>sysvsem</code>.</p>
2735 <div class="example"><p><code>
2736 Mutex default sysvsem<br />
2737 Mutex mpm-accept fcntl:/var/httpd/locks
2741 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2742 <div class="directive-section"><h2><a name="NameVirtualHost" id="NameVirtualHost">NameVirtualHost</a> <a name="namevirtualhost" id="namevirtualhost">Directive</a></h2>
2743 <table class="directive">
2744 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Designates an IP address for name-virtual
2746 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NameVirtualHost <var>addr</var>[:<var>port</var>]</code></td></tr>
2747 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
2748 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2749 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2752 <p>A single <code class="directive">NameVirtualHost</code> directive
2753 identifies a set of identical virtual hosts on which the server will
2754 further select from on the basis of the <em>hostname</em>
2755 requested by the client. The <code class="directive">NameVirtualHost</code>
2756 directive is a required directive if you want to configure
2757 <a href="../vhosts/">name-based virtual hosts</a>.</p>
2759 <p>This directive, and the corresponding <code class="directive">VirtualHost</code>,
2760 <em>must</em> be qualified with a port number if the server supports both HTTP
2761 and HTTPS connections.</p>
2763 <p>Although <var>addr</var> can be a hostname, it is recommended
2764 that you always use an IP address or a wildcard. A wildcard
2765 NameVirtualHost matches only virtualhosts that also have a literal wildcard
2766 as their argument.</p>
2768 <p>In cases where a firewall or other proxy receives the requests and
2769 forwards them on a different IP address to the server, you must specify the
2770 IP address of the physical interface on the machine which will be
2771 servicing the requests. </p>
2773 <p> In the example below, requests received on interface 192.0.2.1 and port 80
2774 will only select among the first two virtual hosts. Requests received on
2775 port 80 on any other interface will only select among the third and fourth
2776 virtual hosts. In the common case where the interface isn't important
2777 to the mapping, only the "*:80" NameVirtualHost and VirtualHost directives
2780 <div class="example"><p><code>
2781 NameVirtualHost 192.0.2.1:80<br />
2782 NameVirtualHost *:80<br /><br />
2784 <VirtualHost 192.0.2.1:80><br />
2785 ServerName namebased-a.example.com<br />
2786 </VirtualHost><br />
2788 <VirtualHost 192.0.2.1:80><br />
2789 Servername namebased-b.example.com<br />
2790 </VirtualHost><br />
2792 <VirtualHost *:80><br />
2793 ServerName namebased-c.example.com <br />
2794 </VirtualHost><br />
2796 <VirtualHost *:80><br />
2797 ServerName namebased-d.example.com <br />
2798 </VirtualHost><br />
2803 <p>If no matching virtual host is found, then the first listed
2804 virtual host that matches the IP address and port will be used.</p>
2807 <p>IPv6 addresses must be enclosed in square brackets, as shown
2808 in the following example:</p>
2810 <div class="example"><p><code>
2811 NameVirtualHost [2001:db8::a00:20ff:fea7:ccea]:8080
2814 <div class="note"><h3>Argument to <code class="directive"><VirtualHost></code>
2816 <p>Note that the argument to the <code class="directive"><VirtualHost></code> directive must
2817 exactly match the argument to the <code class="directive">NameVirtualHost</code> directive.</p>
2819 <div class="example"><p><code>
2820 NameVirtualHost 192.0.2.2:80<br />
2821 <VirtualHost 192.0.2.2:80><br />
2823 </VirtualHost><br />
2829 <li><a href="../vhosts/">Virtual Hosts
2830 documentation</a></li>
2833 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2834 <div class="directive-section"><h2><a name="Options" id="Options">Options</a> <a name="options" id="options">Directive</a></h2>
2835 <table class="directive">
2836 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures what features are available in a particular
2838 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Options
2839 [+|-]<var>option</var> [[+|-]<var>option</var>] ...</code></td></tr>
2840 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Options All</code></td></tr>
2841 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2842 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
2843 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2844 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2846 <p>The <code class="directive">Options</code> directive controls which
2847 server features are available in a particular directory.</p>
2849 <p><var>option</var> can be set to <code>None</code>, in which
2850 case none of the extra features are enabled, or one or more of
2854 <dt><code>All</code></dt>
2856 <dd>All options except for <code>MultiViews</code>. This is the default
2859 <dt><code>ExecCGI</code></dt>
2862 Execution of CGI scripts using <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>
2865 <dt><code>FollowSymLinks</code></dt>
2869 The server will follow symbolic links in this directory.
2871 <p>Even though the server follows the symlink it does <em>not</em>
2872 change the pathname used to match against <code class="directive"><a href="#directory"><Directory></a></code> sections.</p>
2873 <p>Note also, that this option <strong>gets ignored</strong> if set
2874 inside a <code class="directive"><a href="#location"><Location></a></code>
2876 <p>Omitting this option should not be considered a security restriction,
2877 since symlink testing is subject to race conditions that make it
2881 <dt><code>Includes</code></dt>
2884 Server-side includes provided by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
2887 <dt><code>IncludesNOEXEC</code></dt>
2891 Server-side includes are permitted, but the <code>#exec
2892 cmd</code> and <code>#exec cgi</code> are disabled. It is still
2893 possible to <code>#include virtual</code> CGI scripts from
2894 <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>ed
2897 <dt><code>Indexes</code></dt>
2900 If a URL which maps to a directory is requested, and there
2901 is no <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
2902 (<em>e.g.</em>, <code>index.html</code>) in that directory, then
2903 <code class="module"><a href="../mod/mod_autoindex.html">mod_autoindex</a></code> will return a formatted listing
2904 of the directory.</dd>
2906 <dt><code>MultiViews</code></dt>
2909 <a href="../content-negotiation.html">Content negotiated</a>
2910 "MultiViews" are allowed using
2911 <code class="module"><a href="../mod/mod_negotiation.html">mod_negotiation</a></code>.</dd>
2913 <dt><code>SymLinksIfOwnerMatch</code></dt>
2915 <dd>The server will only follow symbolic links for which the
2916 target file or directory is owned by the same user id as the
2919 <div class="note"><h3>Note</h3> <p>This option gets ignored if
2920 set inside a <code class="directive"><a href="#location"><Location></a></code> section.</p>
2921 <p>This option should not be considered a security restriction,
2922 since symlink testing is subject to race conditions that make it
2923 circumventable.</p></div>
2927 <p>Normally, if multiple <code class="directive">Options</code> could
2928 apply to a directory, then the most specific one is used and
2929 others are ignored; the options are not merged. (See <a href="../sections.html#mergin">how sections are merged</a>.)
2930 However if <em>all</em> the options on the
2931 <code class="directive">Options</code> directive are preceded by a
2932 <code>+</code> or <code>-</code> symbol, the options are
2933 merged. Any options preceded by a <code>+</code> are added to the
2934 options currently in force, and any options preceded by a
2935 <code>-</code> are removed from the options currently in
2938 <div class="warning"><h3>Warning</h3>
2939 <p>Mixing <code class="directive">Options</code> with a <code>+</code> or
2940 <code>-</code> with those without is not valid syntax, and is likely
2941 to cause unexpected results.</p>
2944 <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>
2946 <div class="example"><p><code>
2947 <Directory /web/docs><br />
2948 <span class="indent">
2949 Options Indexes FollowSymLinks<br />
2951 </Directory><br />
2953 <Directory /web/docs/spec><br />
2954 <span class="indent">
2955 Options Includes<br />
2960 <p>then only <code>Includes</code> will be set for the
2961 <code>/web/docs/spec</code> directory. However if the second
2962 <code class="directive">Options</code> directive uses the <code>+</code> and
2963 <code>-</code> symbols:</p>
2965 <div class="example"><p><code>
2966 <Directory /web/docs><br />
2967 <span class="indent">
2968 Options Indexes FollowSymLinks<br />
2970 </Directory><br />
2972 <Directory /web/docs/spec><br />
2973 <span class="indent">
2974 Options +Includes -Indexes<br />
2979 <p>then the options <code>FollowSymLinks</code> and
2980 <code>Includes</code> are set for the <code>/web/docs/spec</code>
2983 <div class="note"><h3>Note</h3>
2984 <p>Using <code>-IncludesNOEXEC</code> or
2985 <code>-Includes</code> disables server-side includes completely
2986 regardless of the previous setting.</p>
2989 <p>The default in the absence of any other settings is
2990 <code>All</code>.</p>
2993 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2994 <div class="directive-section"><h2><a name="RLimitCPU" id="RLimitCPU">RLimitCPU</a> <a name="rlimitcpu" id="rlimitcpu">Directive</a></h2>
2995 <table class="directive">
2996 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the CPU consumption of processes launched
2997 by Apache httpd children</td></tr>
2998 <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>
2999 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3000 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3001 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3002 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3003 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3005 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3006 resource limit for all processes and the second parameter sets
3007 the maximum resource limit. Either parameter can be a number,
3008 or <code>max</code> to indicate to the server that the limit should
3009 be set to the maximum allowed by the operating system
3010 configuration. Raising the maximum resource limit requires that
3011 the server is running as <code>root</code>, or in the initial startup
3014 <p>This applies to processes forked off from Apache httpd children
3015 servicing requests, not the Apache httpd children themselves. This
3016 includes CGI scripts and SSI exec commands, but not any
3017 processes forked off from the Apache httpd parent such as piped
3020 <p>CPU resource limits are expressed in seconds per
3025 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3026 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3029 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3030 <div class="directive-section"><h2><a name="RLimitMEM" id="RLimitMEM">RLimitMEM</a> <a name="rlimitmem" id="rlimitmem">Directive</a></h2>
3031 <table class="directive">
3032 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the memory consumption of processes launched
3033 by Apache httpd children</td></tr>
3034 <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>
3035 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3036 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3037 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3038 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3039 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3041 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3042 resource limit for all processes and the second parameter sets
3043 the maximum resource limit. Either parameter can be a number,
3044 or <code>max</code> to indicate to the server that the limit should
3045 be set to the maximum allowed by the operating system
3046 configuration. Raising the maximum resource limit requires that
3047 the server is running as <code>root</code>, or in the initial startup
3050 <p>This applies to processes forked off from Apache httpd children
3051 servicing requests, not the Apache httpd children themselves. This
3052 includes CGI scripts and SSI exec commands, but not any
3053 processes forked off from the Apache httpd parent such as piped
3056 <p>Memory resource limits are expressed in bytes per
3061 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3062 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3065 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3066 <div class="directive-section"><h2><a name="RLimitNPROC" id="RLimitNPROC">RLimitNPROC</a> <a name="rlimitnproc" id="rlimitnproc">Directive</a></h2>
3067 <table class="directive">
3068 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of processes that can be launched by
3069 processes launched by Apache httpd children</td></tr>
3070 <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>
3071 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3072 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3073 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3074 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3075 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3077 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3078 resource limit for all processes and the second parameter sets
3079 the maximum resource limit. Either parameter can be a number,
3080 or <code>max</code> to indicate to the server that the limit
3081 should be set to the maximum allowed by the operating system
3082 configuration. Raising the maximum resource limit requires that
3083 the server is running as <code>root</code>, or in the initial startup
3086 <p>This applies to processes forked off from Apache httpd children
3087 servicing requests, not the Apache httpd children themselves. This
3088 includes CGI scripts and SSI exec commands, but not any
3089 processes forked off from the Apache httpd parent such as piped
3092 <p>Process limits control the number of processes per user.</p>
3094 <div class="note"><h3>Note</h3>
3095 <p>If CGI processes are <strong>not</strong> running
3096 under user ids other than the web server user id, this directive
3097 will limit the number of processes that the server itself can
3098 create. Evidence of this situation will be indicated by
3099 <strong><code>cannot fork</code></strong> messages in the
3100 <code>error_log</code>.</p>
3105 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3106 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3109 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3110 <div class="directive-section"><h2><a name="ScriptInterpreterSource" id="ScriptInterpreterSource">ScriptInterpreterSource</a> <a name="scriptinterpretersource" id="scriptinterpretersource">Directive</a></h2>
3111 <table class="directive">
3112 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
3114 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ScriptInterpreterSource Registry|Registry-Strict|Script</code></td></tr>
3115 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ScriptInterpreterSource Script</code></td></tr>
3116 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3117 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3118 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3119 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3120 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Win32 only;
3121 option <code>Registry-Strict</code> is available in Apache HTTP Server 2.0 and
3124 <p>This directive is used to control how Apache httpd finds the
3125 interpreter used to run CGI scripts. The default setting is
3126 <code>Script</code>. This causes Apache httpd to use the interpreter pointed to
3127 by the shebang line (first line, starting with <code>#!</code>) in the
3128 script. On Win32 systems this line usually looks like:</p>
3130 <div class="example"><p><code>
3131 #!C:/Perl/bin/perl.exe
3134 <p>or, if <code>perl</code> is in the <code>PATH</code>, simply:</p>
3136 <div class="example"><p><code>
3140 <p>Setting <code>ScriptInterpreterSource Registry</code> will
3141 cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
3142 searched using the script file extension (e.g., <code>.pl</code>) as a
3143 search key. The command defined by the registry subkey
3144 <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
3145 <code>Shell\Open\Command</code> is used to open the script file. If the
3146 registry keys cannot be found, Apache httpd falls back to the behavior of the
3147 <code>Script</code> option.</p>
3149 <div class="warning"><h3>Security</h3>
3150 <p>Be careful when using <code>ScriptInterpreterSource
3151 Registry</code> with <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>'ed directories, because
3152 Apache httpd will try to execute <strong>every</strong> file within this
3153 directory. The <code>Registry</code> setting may cause undesired
3154 program calls on files which are typically not executed. For
3155 example, the default open command on <code>.htm</code> files on
3156 most Windows systems will execute Microsoft Internet Explorer, so
3157 any HTTP request for an <code>.htm</code> file existing within the
3158 script directory would start the browser in the background on the
3159 server. This is a good way to crash your system within a minute or
3163 <p>The option <code>Registry-Strict</code> which is new in Apache HTTP Server
3164 2.0 does the same thing as <code>Registry</code> but uses only the
3165 subkey <code>Shell\ExecCGI\Command</code>. The
3166 <code>ExecCGI</code> key is not a common one. It must be
3167 configured manually in the windows registry and hence prevents
3168 accidental program calls on your system.</p>
3171 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3172 <div class="directive-section"><h2><a name="SeeRequestTail" id="SeeRequestTail">SeeRequestTail</a> <a name="seerequesttail" id="seerequesttail">Directive</a></h2>
3173 <table class="directive">
3174 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine if mod_status displays the first 63 characters
3175 of a request or the last 63, assuming the request itself is greater than
3177 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SeeRequestTail On|Off</code></td></tr>
3178 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SeeRequestTail Off</code></td></tr>
3179 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3180 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3181 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3182 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.2.7 and later.</td></tr>
3184 <p>mod_status with <code>ExtendedStatus On</code>
3185 displays the actual request being handled.
3186 For historical purposes, only 63 characters of the request
3187 are actually stored for display purposes. This directive
3188 controls whether the 1st 63 characters are stored (the previous
3189 behavior and the default) or if the last 63 characters are. This
3190 is only applicable, of course, if the length of the request is
3191 64 characters or greater.</p>
3193 <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:
3196 <table class="bordered">
3198 <th>Off (default)</th>
3199 <td>GET /disk1/storage/apache/htdocs/images/imagestore1/food/apples</td>
3203 <td>orage/apache/htdocs/images/imagestore1/food/apples.jpg HTTP/1.1</td>
3209 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3210 <div class="directive-section"><h2><a name="ServerAdmin" id="ServerAdmin">ServerAdmin</a> <a name="serveradmin" id="serveradmin">Directive</a></h2>
3211 <table class="directive">
3212 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Email address that the server includes in error
3213 messages sent to the client</td></tr>
3214 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAdmin <var>email-address</var>|<var>URL</var></code></td></tr>
3215 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3216 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3217 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3219 <p>The <code class="directive">ServerAdmin</code> sets the contact address
3220 that the server includes in any error messages it returns to the
3221 client. If the <code>httpd</code> doesn't recognize the supplied argument
3223 assumes, that it's an <var>email-address</var> and prepends it with
3224 <code>mailto:</code> in hyperlink targets. However, it's recommended to
3225 actually use an email address, since there are a lot of CGI scripts that
3226 make that assumption. If you want to use an URL, it should point to another
3227 server under your control. Otherwise users may not be able to contact you in
3230 <p>It may be worth setting up a dedicated address for this, e.g.</p>
3232 <div class="example"><p><code>
3233 ServerAdmin www-admin@foo.example.com
3235 <p>as users do not always mention that they are talking about the
3239 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3240 <div class="directive-section"><h2><a name="ServerAlias" id="ServerAlias">ServerAlias</a> <a name="serveralias" id="serveralias">Directive</a></h2>
3241 <table class="directive">
3242 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Alternate names for a host used when matching requests
3243 to name-virtual hosts</td></tr>
3244 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</code></td></tr>
3245 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
3246 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3247 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3249 <p>The <code class="directive">ServerAlias</code> directive sets the
3250 alternate names for a host, for use with <a href="../vhosts/name-based.html">name-based virtual hosts</a>. The
3251 <code class="directive">ServerAlias</code> may include wildcards, if appropriate.</p>
3253 <div class="example"><p><code>
3254 <VirtualHost *:80><br />
3255 ServerName server.domain.com<br />
3256 ServerAlias server server2.domain.com server2<br />
3257 ServerAlias *.example.com<br />
3258 UseCanonicalName Off<br />
3260 </VirtualHost>
3265 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3266 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
3269 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3270 <div class="directive-section"><h2><a name="ServerName" id="ServerName">ServerName</a> <a name="servername" id="servername">Directive</a></h2>
3271 <table class="directive">
3272 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hostname and port that the server uses to identify
3274 <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>
3275 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3276 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3277 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3279 <p>The <code class="directive">ServerName</code> directive sets the
3280 request scheme, hostname and
3281 port that the server uses to identify itself. This is used when
3282 creating redirection URLs. For example, if the name of the
3283 machine hosting the web server is <code>simple.example.com</code>,
3284 but the machine also has the DNS alias <code>www.example.com</code>
3285 and you wish the web server to be so identified, the following
3286 directive should be used:</p>
3288 <div class="example"><p><code>
3289 ServerName www.example.com:80
3292 <p>The <code class="directive">ServerName</code> directive
3293 may appear anywhere within the definition of a server. However,
3294 each appearance overrides the previous appearance (within that
3297 <p>If no <code class="directive">ServerName</code> is specified, then the
3298 server attempts to deduce the hostname by performing a reverse
3299 lookup on the IP address. If no port is specified in the
3300 <code class="directive">ServerName</code>, then the server will use the
3301 port from the incoming request. For optimal reliability and
3302 predictability, you should specify an explicit hostname and port
3303 using the <code class="directive">ServerName</code> directive.</p>
3305 <p>If you are using <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
3306 the <code class="directive">ServerName</code> inside a
3307 <code class="directive"><a href="#virtualhost"><VirtualHost></a></code>
3308 section specifies what hostname must appear in the request's
3309 <code>Host:</code> header to match this virtual host.</p>
3312 <p>Sometimes, the server runs behind a device that processes SSL,
3313 such as a reverse proxy, load balancer or SSL offload
3314 appliance. When this is the case, specify the
3315 <code>https://</code> scheme and the port number to which the
3316 clients connect in the <code class="directive">ServerName</code> directive
3317 to make sure that the server generates the correct
3318 self-referential URLs.
3321 <p>See the description of the
3322 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> and
3323 <code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code> directives for
3324 settings which determine whether self-referential URLs (e.g., by the
3325 <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> module) will refer to the
3326 specified port, or to the port number given in the client's request.
3332 <li><a href="../dns-caveats.html">Issues Regarding DNS and
3333 Apache HTTP Server</a></li>
3334 <li><a href="../vhosts/">Apache HTTP Server virtual host
3335 documentation</a></li>
3336 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3337 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
3338 <li><code class="directive"><a href="#namevirtualhost">NameVirtualHost</a></code></li>
3339 <li><code class="directive"><a href="#serveralias">ServerAlias</a></code></li>
3342 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3343 <div class="directive-section"><h2><a name="ServerPath" id="ServerPath">ServerPath</a> <a name="serverpath" id="serverpath">Directive</a></h2>
3344 <table class="directive">
3345 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Legacy URL pathname for a name-based virtual host that
3346 is accessed by an incompatible browser</td></tr>
3347 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerPath <var>URL-path</var></code></td></tr>
3348 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
3349 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3350 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3352 <p>The <code class="directive">ServerPath</code> directive sets the legacy
3353 URL pathname for a host, for use with <a href="../vhosts/">name-based virtual hosts</a>.</p>
3357 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
3360 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3361 <div class="directive-section"><h2><a name="ServerRoot" id="ServerRoot">ServerRoot</a> <a name="serverroot" id="serverroot">Directive</a></h2>
3362 <table class="directive">
3363 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server installation</td></tr>
3364 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerRoot <var>directory-path</var></code></td></tr>
3365 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerRoot /usr/local/apache</code></td></tr>
3366 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3367 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3368 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3370 <p>The <code class="directive">ServerRoot</code> directive sets the
3371 directory in which the server lives. Typically it will contain the
3372 subdirectories <code>conf/</code> and <code>logs/</code>. Relative
3373 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
3374 relative to this directory.</p>
3376 <div class="example"><h3>Example</h3><p><code>
3377 ServerRoot /home/httpd
3383 <li><a href="../invoking.html">the <code>-d</code>
3384 option to <code>httpd</code></a></li>
3385 <li><a href="../misc/security_tips.html#serverroot">the
3386 security tips</a> for information on how to properly set
3387 permissions on the <code class="directive">ServerRoot</code></li>
3390 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3391 <div class="directive-section"><h2><a name="ServerSignature" id="ServerSignature">ServerSignature</a> <a name="serversignature" id="serversignature">Directive</a></h2>
3392 <table class="directive">
3393 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the footer on server-generated documents</td></tr>
3394 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerSignature On|Off|EMail</code></td></tr>
3395 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerSignature Off</code></td></tr>
3396 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3397 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3398 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3399 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3401 <p>The <code class="directive">ServerSignature</code> directive allows the
3402 configuration of a trailing footer line under server-generated
3403 documents (error messages, <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> ftp directory
3404 listings, <code class="module"><a href="../mod/mod_info.html">mod_info</a></code> output, ...). The reason why you
3405 would want to enable such a footer line is that in a chain of proxies,
3406 the user often has no possibility to tell which of the chained servers
3407 actually produced a returned error message.</p>
3409 <p>The <code>Off</code>
3410 setting, which is the default, suppresses the footer line (and is
3411 therefore compatible with the behavior of Apache-1.2 and
3412 below). The <code>On</code> setting simply adds a line with the
3413 server version number and <code class="directive"><a href="#servername">ServerName</a></code> of the serving virtual host,
3414 and the <code>EMail</code> setting additionally creates a
3415 "mailto:" reference to the <code class="directive"><a href="#serveradmin">ServerAdmin</a></code> of the referenced
3418 <p>After version 2.0.44, the details of the server version number
3419 presented are controlled by the <code class="directive"><a href="#servertokens">ServerTokens</a></code> directive.</p>
3423 <li><code class="directive"><a href="#servertokens">ServerTokens</a></code></li>
3426 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3427 <div class="directive-section"><h2><a name="ServerTokens" id="ServerTokens">ServerTokens</a> <a name="servertokens" id="servertokens">Directive</a></h2>
3428 <table class="directive">
3429 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the <code>Server</code> HTTP response
3431 <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>
3432 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerTokens Full</code></td></tr>
3433 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3434 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3435 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3437 <p>This directive controls whether <code>Server</code> response
3438 header field which is sent back to clients includes a
3439 description of the generic OS-type of the server as well as
3440 information about compiled-in modules.</p>
3443 <dt><code>ServerTokens Full</code> (or not specified)</dt>
3445 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.1
3446 (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
3448 <dt><code>ServerTokens Prod[uctOnly]</code></dt>
3450 <dd>Server sends (<em>e.g.</em>): <code>Server:
3453 <dt><code>ServerTokens Major</code></dt>
3455 <dd>Server sends (<em>e.g.</em>): <code>Server:
3456 Apache/2</code></dd>
3458 <dt><code>ServerTokens Minor</code></dt>
3460 <dd>Server sends (<em>e.g.</em>): <code>Server:
3461 Apache/2.4</code></dd>
3463 <dt><code>ServerTokens Min[imal]</code></dt>
3465 <dd>Server sends (<em>e.g.</em>): <code>Server:
3466 Apache/2.4.1</code></dd>
3468 <dt><code>ServerTokens OS</code></dt>
3470 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.1
3475 <p>This setting applies to the entire server, and cannot be
3476 enabled or disabled on a virtualhost-by-virtualhost basis.</p>
3478 <p>After version 2.0.44, this directive also controls the
3479 information presented by the <code class="directive"><a href="#serversignature">ServerSignature</a></code> directive.</p>
3481 <div class="note">Setting <code class="directive">ServerTokens</code> to less than
3482 <code>minimal</code> is not recommended because it makes it more
3483 difficult to debug interoperational problems. Also note that
3484 disabling the Server: header does nothing at all to make your
3485 server more secure; the idea of "security through obscurity"
3486 is a myth and leads to a false sense of safety.</div>
3491 <li><code class="directive"><a href="#serversignature">ServerSignature</a></code></li>
3494 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3495 <div class="directive-section"><h2><a name="SetHandler" id="SetHandler">SetHandler</a> <a name="sethandler" id="sethandler">Directive</a></h2>
3496 <table class="directive">
3497 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be processed by a
3499 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetHandler <var>handler-name</var>|None</code></td></tr>
3500 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3501 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3502 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3503 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3504 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Moved into the core in Apache httpd 2.0</td></tr>
3506 <p>When placed into an <code>.htaccess</code> file or a
3507 <code class="directive"><a href="#directory"><Directory></a></code> or
3508 <code class="directive"><a href="#location"><Location></a></code>
3509 section, this directive forces all matching files to be parsed
3510 through the <a href="../handler.html">handler</a> given by
3511 <var>handler-name</var>. For example, if you had a directory you
3512 wanted to be parsed entirely as imagemap rule files, regardless
3513 of extension, you might put the following into an
3514 <code>.htaccess</code> file in that directory:</p>
3516 <div class="example"><p><code>
3517 SetHandler imap-file
3520 <p>Another example: if you wanted to have the server display a
3521 status report whenever a URL of
3522 <code>http://servername/status</code> was called, you might put
3523 the following into <code>httpd.conf</code>:</p>
3525 <div class="example"><p><code>
3526 <Location /status><br />
3527 <span class="indent">
3528 SetHandler server-status<br />
3533 <p>You can override an earlier defined <code class="directive">SetHandler</code>
3534 directive by using the value <code>None</code>.</p>
3535 <p><strong>Note:</strong> because SetHandler overrides default handlers,
3536 normal behaviour such as handling of URLs ending in a slash (/) as
3537 directories or index files is suppressed.</p>
3541 <li><code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code></li>
3544 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3545 <div class="directive-section"><h2><a name="SetInputFilter" id="SetInputFilter">SetInputFilter</a> <a name="setinputfilter" id="setinputfilter">Directive</a></h2>
3546 <table class="directive">
3547 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process client requests and POST
3549 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetInputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
3550 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3551 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3552 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3553 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3555 <p>The <code class="directive">SetInputFilter</code> directive sets the
3556 filter or filters which will process client requests and POST
3557 input when they are received by the server. This is in addition to
3558 any filters defined elsewhere, including the
3559 <code class="directive"><a href="../mod/mod_mime.html#addinputfilter">AddInputFilter</a></code>
3562 <p>If more than one filter is specified, they must be separated
3563 by semicolons in the order in which they should process the
3568 <li><a href="../filter.html">Filters</a> documentation</li>
3571 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3572 <div class="directive-section"><h2><a name="SetOutputFilter" id="SetOutputFilter">SetOutputFilter</a> <a name="setoutputfilter" id="setoutputfilter">Directive</a></h2>
3573 <table class="directive">
3574 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process responses from the
3576 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
3577 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3578 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3579 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3580 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3582 <p>The <code class="directive">SetOutputFilter</code> directive sets the filters
3583 which will process responses from the server before they are
3584 sent to the client. This is in addition to any filters defined
3585 elsewhere, including the
3586 <code class="directive"><a href="../mod/mod_mime.html#addoutputfilter">AddOutputFilter</a></code>
3589 <p>For example, the following configuration will process all files
3590 in the <code>/www/data/</code> directory for server-side
3593 <div class="example"><p><code>
3594 <Directory /www/data/><br />
3595 <span class="indent">
3596 SetOutputFilter INCLUDES<br />
3601 <p>If more than one filter is specified, they must be separated
3602 by semicolons in the order in which they should process the
3607 <li><a href="../filter.html">Filters</a> documentation</li>
3610 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3611 <div class="directive-section"><h2><a name="TimeOut" id="TimeOut">TimeOut</a> <a name="timeout" id="timeout">Directive</a></h2>
3612 <table class="directive">
3613 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for
3614 certain events before failing a request</td></tr>
3615 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TimeOut <var>seconds</var></code></td></tr>
3616 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TimeOut 300</code></td></tr>
3617 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3618 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3619 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3621 <p>The <code class="directive">TimeOut</code> directive defines the length
3622 of time Apache httpd will wait for I/O in various circumstances:</p>
3625 <li>When reading data from the client, the length of time to
3626 wait for a TCP packet to arrive if the read buffer is
3629 <li>When writing data to the client, the length of time to wait
3630 for an acknowledgement of a packet if the send buffer is
3633 <li>In <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>, the length of time to wait for
3634 output from a CGI script.</li>
3636 <li>In <code class="module"><a href="../mod/mod_ext_filter.html">mod_ext_filter</a></code>, the length of time to
3637 wait for output from a filtering process.</li>
3639 <li>In <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>, the default timeout value if
3640 <code class="directive"><a href="../mod/mod_proxy.html#proxytimeout">ProxyTimeout</a></code> is not
3646 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3647 <div class="directive-section"><h2><a name="TraceEnable" id="TraceEnable">TraceEnable</a> <a name="traceenable" id="traceenable">Directive</a></h2>
3648 <table class="directive">
3649 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines the behaviour on <code>TRACE</code>
3651 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TraceEnable <var>[on|off|extended]</var></code></td></tr>
3652 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TraceEnable on</code></td></tr>
3653 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3654 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3655 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3656 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 1.3.34, 2.0.55 and later</td></tr>
3658 <p>This directive overrides the behavior of <code>TRACE</code> for both
3659 the core server and <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>. The default
3660 <code>TraceEnable on</code> permits <code>TRACE</code> requests per
3661 RFC 2616, which disallows any request body to accompany the request.
3662 <code>TraceEnable off</code> causes the core server and
3663 <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> to return a <code>405</code> (Method not
3664 allowed) error to the client.</p>
3666 <p>Finally, for testing and diagnostic purposes only, request
3667 bodies may be allowed using the non-compliant <code>TraceEnable
3668 extended</code> directive. The core (as an origin server) will
3669 restrict the request body to 64k (plus 8k for chunk headers if
3670 <code>Transfer-Encoding: chunked</code> is used). The core will
3671 reflect the full headers and all chunk headers with the response
3672 body. As a proxy server, the request body is not restricted to 64k.</p>
3675 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3676 <div class="directive-section"><h2><a name="UnDefine" id="UnDefine">UnDefine</a> <a name="undefine" id="undefine">Directive</a></h2>
3677 <table class="directive">
3678 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Undefine the existence of a variable</td></tr>
3679 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UnDefine <var>parameter-name</var></code></td></tr>
3680 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3681 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3682 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3684 <p>Undoes the effect of a <code class="directive"><a href="#define">Define</a></code> or
3685 of passing a <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</p>
3686 <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
3687 <code>-D</code> arguments in any startup scripts.</p>
3690 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3691 <div class="directive-section"><h2><a name="UseCanonicalName" id="UseCanonicalName">UseCanonicalName</a> <a name="usecanonicalname" id="usecanonicalname">Directive</a></h2>
3692 <table class="directive">
3693 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own name and
3695 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalName On|Off|DNS</code></td></tr>
3696 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalName Off</code></td></tr>
3697 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3698 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3699 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3701 <p>In many situations Apache httpd must construct a <em>self-referential</em>
3702 URL -- that is, a URL that refers back to the same server. With
3703 <code>UseCanonicalName On</code> Apache httpd will use the hostname and port
3704 specified in the <code class="directive"><a href="#servername">ServerName</a></code>
3705 directive to construct the canonical name for the server. This name
3706 is used in all self-referential URLs, and for the values of
3707 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>
3709 <p>With <code>UseCanonicalName Off</code> Apache httpd will form
3710 self-referential URLs using the hostname and port supplied by
3711 the client if any are supplied (otherwise it will use the
3712 canonical name, as defined above). These values are the same
3713 that are used to implement <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
3714 and are available with the same clients. The CGI variables
3715 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
3716 constructed from the client supplied values as well.</p>
3718 <p>An example where this may be useful is on an intranet server
3719 where you have users connecting to the machine using short
3720 names such as <code>www</code>. You'll notice that if the users
3721 type a shortname, and a URL which is a directory, such as
3722 <code>http://www/splat</code>, <em>without the trailing
3723 slash</em> then Apache httpd will redirect them to
3724 <code>http://www.domain.com/splat/</code>. If you have
3725 authentication enabled, this will cause the user to have to
3726 authenticate twice (once for <code>www</code> and once again
3727 for <code>www.domain.com</code> -- see <a href="http://httpd.apache.org/docs/misc/FAQ.html#prompted-twice">the
3728 FAQ on this subject for more information</a>). But if
3729 <code class="directive">UseCanonicalName</code> is set <code>Off</code>, then
3730 Apache httpd will redirect to <code>http://www/splat/</code>.</p>
3732 <p>There is a third option, <code>UseCanonicalName DNS</code>,
3733 which is intended for use with mass IP-based virtual hosting to
3734 support ancient clients that do not provide a
3735 <code>Host:</code> header. With this option Apache httpd does a
3736 reverse DNS lookup on the server IP address that the client
3737 connected to in order to work out self-referential URLs.</p>
3739 <div class="warning"><h3>Warning</h3>
3740 <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>
3741 they may be broken by this option. The client is essentially free
3742 to give whatever value they want as a hostname. But if the CGI is
3743 only using <code>SERVER_NAME</code> to construct self-referential URLs
3744 then it should be just fine.</p>
3749 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
3750 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
3751 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
3754 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3755 <div class="directive-section"><h2><a name="UseCanonicalPhysicalPort" id="UseCanonicalPhysicalPort">UseCanonicalPhysicalPort</a> <a name="usecanonicalphysicalport" id="usecanonicalphysicalport">Directive</a></h2>
3756 <table class="directive">
3757 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own name and
3759 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalPhysicalPort On|Off</code></td></tr>
3760 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalPhysicalPort Off</code></td></tr>
3761 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3762 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3763 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3765 <p>In many situations Apache httpd must construct a <em>self-referential</em>
3766 URL -- that is, a URL that refers back to the same server. With
3767 <code>UseCanonicalPhysicalPort On</code> Apache httpd will, when
3768 constructing the canonical port for the server to honor
3769 the <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> directive,
3770 provide the actual physical port number being used by this request
3771 as a potential port. With <code>UseCanonicalPhysicalPort Off</code>
3772 Apache httpd will not ever use the actual physical port number, instead
3773 relying on all configured information to construct a valid port number.</p>
3775 <div class="note"><h3>Note</h3>
3776 <p>The ordering of when the physical port is used is as follows:<br /><br />
3777 <code>UseCanonicalName On</code></p>
3779 <li>Port provided in <code>Servername</code></li>
3780 <li>Physical port</li>
3781 <li>Default port</li>
3783 <code>UseCanonicalName Off | DNS</code>
3785 <li>Parsed port from <code>Host:</code> header</li>
3786 <li>Physical port</li>
3787 <li>Port provided in <code>Servername</code></li>
3788 <li>Default port</li>
3791 <p>With <code>UseCanonicalPhysicalPort Off</code>, the
3792 physical ports are removed from the ordering.</p>
3798 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3799 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
3800 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
3803 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3804 <div class="directive-section"><h2><a name="VirtualHost" id="VirtualHost"><VirtualHost></a> <a name="virtualhost" id="virtualhost">Directive</a></h2>
3805 <table class="directive">
3806 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only to a specific
3807 hostname or IP address</td></tr>
3808 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><VirtualHost
3809 <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
3810 ...> ... </VirtualHost></code></td></tr>
3811 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3812 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3813 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3815 <p><code class="directive"><VirtualHost></code> and
3816 <code></VirtualHost></code> are used to enclose a group of
3817 directives that will apply only to a particular virtual host. Any
3818 directive that is allowed in a virtual host context may be
3819 used. When the server receives a request for a document on a
3820 particular virtual host, it uses the configuration directives
3821 enclosed in the <code class="directive"><VirtualHost></code>
3822 section. <var>Addr</var> can be:</p>
3825 <li>The IP address of the virtual host;</li>
3827 <li>A fully qualified domain name for the IP address of the
3828 virtual host (not recommended);</li>
3830 <li>The character <code>*</code>, which is used only in combination with
3831 <code>NameVirtualHost *</code> to match all IP addresses; or</li>
3833 <li>The string <code>_default_</code>, which is used only
3834 with IP virtual hosting to catch unmatched IP addresses.</li>
3837 <div class="example"><h3>Example</h3><p><code>
3838 <VirtualHost 10.1.2.3><br />
3839 <span class="indent">
3840 ServerAdmin webmaster@host.example.com<br />
3841 DocumentRoot /www/docs/host.example.com<br />
3842 ServerName host.example.com<br />
3843 ErrorLog logs/host.example.com-error_log<br />
3844 TransferLog logs/host.example.com-access_log<br />
3846 </VirtualHost>
3850 <p>IPv6 addresses must be specified in square brackets because
3851 the optional port number could not be determined otherwise. An
3852 IPv6 example is shown below:</p>
3854 <div class="example"><p><code>
3855 <VirtualHost [2001:db8::a00:20ff:fea7:ccea]><br />
3856 <span class="indent">
3857 ServerAdmin webmaster@host.example.com<br />
3858 DocumentRoot /www/docs/host.example.com<br />
3859 ServerName host.example.com<br />
3860 ErrorLog logs/host.example.com-error_log<br />
3861 TransferLog logs/host.example.com-access_log<br />
3863 </VirtualHost>
3866 <p>Each Virtual Host must correspond to a different IP address,
3867 different port number or a different host name for the server,
3868 in the former case the server machine must be configured to
3869 accept IP packets for multiple addresses. (If the machine does
3870 not have multiple network interfaces, then this can be
3871 accomplished with the <code>ifconfig alias</code> command -- if
3872 your OS supports it).</p>
3874 <div class="note"><h3>Note</h3>
3875 <p>The use of <code class="directive"><VirtualHost></code> does
3876 <strong>not</strong> affect what addresses Apache httpd listens on. You
3877 may need to ensure that Apache httpd is listening on the correct addresses
3878 using <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>.</p>
3881 <p>When using IP-based virtual hosting, the special name
3882 <code>_default_</code> can be specified in
3883 which case this virtual host will match any IP address that is
3884 not explicitly listed in another virtual host. In the absence
3885 of any <code>_default_</code> virtual host the "main" server config,
3886 consisting of all those definitions outside any VirtualHost
3887 section, is used when no IP-match occurs.</p>
3889 <p>You can specify a <code>:port</code> to change the port that is
3890 matched. If unspecified then it defaults to the same port as the
3891 most recent <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>
3892 statement of the main server. You may also specify <code>:*</code>
3893 to match all ports on that address. (This is recommended when used
3894 with <code>_default_</code>.)</p>
3896 <p>A <code class="directive"><a href="#servername">ServerName</a></code> should be
3897 specified inside each <code class="directive"><VirtualHost></code> block. If it is absent, the
3898 <code class="directive"><a href="#servername">ServerName</a></code> from the "main"
3899 server configuration will be inherited.</p>
3901 <p>If no matching virtual host is found, then the first listed
3902 virtual host that matches the IP address will be used. As a
3903 consequence, the first listed virtual host is the default virtual
3906 <div class="warning"><h3>Security</h3>
3907 <p>See the <a href="../misc/security_tips.html">security tips</a>
3908 document for details on why your security could be compromised if the
3909 directory where log files are stored is writable by anyone other
3910 than the user that starts the server.</p>
3915 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
3916 <li><a href="../dns-caveats.html">Issues Regarding DNS and
3917 Apache HTTP Server</a></li>
3918 <li><a href="../bind.html">Setting
3919 which addresses and ports Apache HTTP Server uses</a></li>
3920 <li><a href="../sections.html">How <Directory>, <Location>
3921 and <Files> sections work</a> for an explanation of how these
3922 different sections are combined when a request is received</li>
3926 <div class="bottomlang">
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3932 </div><div id="footer">
3933 <p class="apache">Copyright 2010 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p>
3934 <p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div>