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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 modifiers to the format
1133 string item. A <code>-</code> (minus) modifier 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) modifier. If an
1136 item with the plus modifier does not produce any output, the whole line is
1139 <p>A number as modifier can be used to assign a log severity level to a
1140 format item. The item will only be logged if the severity of the log
1141 message is not higher than the specified log severity level. The number can
1142 range from 1 (alert) over 4 (warn) and 7 (debug) to 15 (trace8).</p>
1144 <p>Some format string items accept additional parameters in braces.</p>
1146 <table class="bordered"><tr class="header"><th>Format String</th> <th>Description</th></tr>
1147 <tr><td><code>%%</code></td>
1148 <td>The percent sign</td></tr>
1149 <tr class="odd"><td><code>%...a</code></td>
1150 <td>Remote IP-address and port</td></tr>
1151 <tr><td><code>%...A</code></td>
1152 <td>Local IP-address and port</td></tr>
1153 <tr class="odd"><td><code>%...{name}e</code></td>
1154 <td>Request environment variable <code>name</code></td></tr>
1155 <tr><td><code>%...E</code></td>
1156 <td>APR/OS error status code and string</td></tr>
1157 <tr class="odd"><td><code>%...F</code></td>
1158 <td>Source file name and line number of the log call</td></tr>
1159 <tr><td><code>%...{name}i</code></td>
1160 <td>Request header <code>name</code></td></tr>
1161 <tr class="odd"><td><code>%...k</code></td>
1162 <td>Number of keep-alive requests on this connection</td></tr>
1163 <tr><td><code>%...l</code></td>
1164 <td>Loglevel of the message</td></tr>
1165 <tr class="odd"><td><code>%...L</code></td>
1166 <td>Log ID of the request</td></tr>
1167 <tr><td><code>%...{c}L</code></td>
1168 <td>Log ID of the connection</td></tr>
1169 <tr class="odd"><td><code>%...{C}L</code></td>
1170 <td>Log ID of the connection if used in connection scope, empty otherwise</td></tr>
1171 <tr><td><code>%...m</code></td>
1172 <td>Name of the module logging the message</td></tr>
1173 <tr class="odd"><td><code>%M</code></td>
1174 <td>The actual log message</td></tr>
1175 <tr><td><code>%...{name}n</code></td>
1176 <td>Request note <code>name</code></td></tr>
1177 <tr class="odd"><td><code>%...P</code></td>
1178 <td>Process ID of current process</td></tr>
1179 <tr><td><code>%...T</code></td>
1180 <td>Thread ID of current thread</td></tr>
1181 <tr class="odd"><td><code>%...t</code></td>
1182 <td>The current time</td></tr>
1183 <tr><td><code>%...{u}t</code></td>
1184 <td>The current time including micro-seconds</td></tr>
1185 <tr class="odd"><td><code>%...{cu}t</code></td>
1186 <td>The current time in compact ISO 8601 format, including
1187 micro-seconds</td></tr>
1188 <tr><td><code>\ </code> (backslash space)</td>
1189 <td>Non-field delimiting space</td></tr>
1190 <tr class="odd"><td><code>% </code> (percent space)</td>
1191 <td>Field delimiter (no output)</td></tr>
1194 <p>The log ID format <code>%L</code> produces a unique id for a connection
1195 or request. This can be used to correlate which log lines belong to the
1196 same connection or request, which request happens on which connection.
1197 A <code>%L</code> format string is also available in
1198 <code class="module"><a href="../mod/mod_log_config.html">mod_log_config</a></code>, to allow to correlate access log entries
1199 with error log lines. If <code class="module"><a href="../mod/mod_unique_id.html">mod_unique_id</a></code> is loaded, its
1200 unique id will be used as log ID for requests.</p>
1202 <div class="example"><h3>Example (somewhat similar to default format)</h3><p><code>
1203 ErrorLogFormat "[%{u}t] [%-m:%l] [pid %P] %7F: %E: [client\ %a]
1204 %M% ,\ referer\ %{Referer}i"
1207 <div class="example"><h3>Example (similar to the 2.2.x format)</h3><p><code>
1208 ErrorLogFormat "[%t] [%l] %7F: %E: [client\ %a]
1209 %M% ,\ referer\ %{Referer}i"
1212 <div class="example"><h3>Advanced example with request/connection log IDs</h3><p><code>
1213 ErrorLogFormat "[%{uc}t] [%-m:%-l] [R:%L] [C:%{C}L] %7F: %E: %M"<br />
1214 ErrorLogFormat request "[%{uc}t] [R:%L] Request %k on C:%{c}L pid:%P tid:%T"<br />
1215 ErrorLogFormat request "[%{uc}t] [R:%L] UA:'%+{User-Agent}i'"<br />
1216 ErrorLogFormat request "[%{uc}t] [R:%L] Referer:'%+{Referer}i'"<br />
1217 ErrorLogFormat connection "[%{uc}t] [C:%{c}L] local\ %a remote\ %A"<br />
1223 <li><code class="directive"><a href="#errorlog">ErrorLog</a></code></li>
1224 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
1225 <li><a href="../logs.html">Apache HTTP Server Log Files</a></li>
1228 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1229 <div class="directive-section"><h2><a name="ExtendedStatus" id="ExtendedStatus">ExtendedStatus</a> <a name="extendedstatus" id="extendedstatus">Directive</a></h2>
1230 <table class="directive">
1231 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Keep track of extended status information for each
1233 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ExtendedStatus On|Off</code></td></tr>
1234 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ExtendedStatus Off[*]</code></td></tr>
1235 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
1236 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1237 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1239 <p>This option tracks additional data per worker about the
1240 currently executing request, and a utilization summary; you
1241 can see these variables during runtime by configuring
1242 <code class="module"><a href="../mod/mod_status.html">mod_status</a></code>. Note that other modules may
1243 rely on this scoreboard.</p>
1245 <p>This setting applies to the entire server, and cannot be
1246 enabled or disabled on a virtualhost-by-virtualhost basis.
1247 The collection of extended status information can slow down
1248 the server. Also note that this setting cannot be changed
1249 during a graceful restart.</p>
1252 <p>Note that loading <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> will change
1253 the default behavior to ExtendedStatus On, while other
1254 third party modules may do the same. Such modules rely on
1255 collecting detailed information about the state of all workers.
1256 The default is changed by <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> beginning
1257 with version 2.3.6; the previous default was always Off.</p>
1262 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1263 <div class="directive-section"><h2><a name="FileETag" id="FileETag">FileETag</a> <a name="fileetag" id="fileetag">Directive</a></h2>
1264 <table class="directive">
1265 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>File attributes used to create the ETag
1266 HTTP response header for static files</td></tr>
1267 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>FileETag <var>component</var> ...</code></td></tr>
1268 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>FileETag INode MTime Size</code></td></tr>
1269 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1270 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1271 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1272 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1275 The <code class="directive">FileETag</code> directive configures the file
1276 attributes that are used to create the <code>ETag</code> (entity
1277 tag) response header field when the document is based on a static file.
1278 (The <code>ETag</code> value is used in cache management to save
1279 network bandwidth.) The
1280 <code class="directive">FileETag</code> directive allows you to choose
1281 which of these -- if any -- should be used. The recognized keywords are:
1285 <dt><strong>INode</strong></dt>
1286 <dd>The file's i-node number will be included in the calculation</dd>
1287 <dt><strong>MTime</strong></dt>
1288 <dd>The date and time the file was last modified will be included</dd>
1289 <dt><strong>Size</strong></dt>
1290 <dd>The number of bytes in the file will be included</dd>
1291 <dt><strong>All</strong></dt>
1292 <dd>All available fields will be used. This is equivalent to:
1293 <div class="example"><p><code>FileETag INode MTime Size</code></p></div></dd>
1294 <dt><strong>None</strong></dt>
1295 <dd>If a document is file-based, no <code>ETag</code> field will be
1296 included in the response</dd>
1299 <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
1300 keywords may be prefixed with either <code>+</code> or <code>-</code>,
1301 which allow changes to be made to the default setting inherited
1302 from a broader scope. Any keyword appearing without such a prefix
1303 immediately and completely cancels the inherited setting.</p>
1305 <p>If a directory's configuration includes
1306 <code>FileETag INode MTime Size</code>, and a
1307 subdirectory's includes <code>FileETag -INode</code>,
1308 the setting for that subdirectory (which will be inherited by
1309 any sub-subdirectories that don't override it) will be equivalent to
1310 <code>FileETag MTime Size</code>.</p>
1311 <div class="warning"><h3>Warning</h3>
1312 Do not change the default for directories or locations that have WebDAV
1313 enabled and use <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> as a storage provider.
1314 <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> uses <code>INode MTime Size</code>
1315 as a fixed format for <code>ETag</code> comparisons on conditional requests.
1316 These conditional requests will break if the <code>ETag</code> format is
1317 changed via <code class="directive">FileETag</code>.
1319 <div class="note"><h3>Server Side Includes</h3>
1320 An ETag is not generated for responses parsed by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>,
1321 since the response entity can change without a change of the INode, MTime, or Size
1322 of the static file with embedded SSI directives.
1327 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1328 <div class="directive-section"><h2><a name="Files" id="Files"><Files></a> <a name="files" id="files">Directive</a></h2>
1329 <table class="directive">
1330 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to matched
1332 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Files <var>filename</var>> ... </Files></code></td></tr>
1333 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1334 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1335 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1336 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1338 <p>The <code class="directive"><Files></code> directive
1339 limits the scope of the enclosed directives by filename. It is comparable
1340 to the <code class="directive"><a href="#directory"><Directory></a></code>
1341 and <code class="directive"><a href="#location"><Location></a></code>
1342 directives. It should be matched with a <code></Files></code>
1343 directive. The directives given within this section will be applied to
1344 any object with a basename (last component of filename) matching the
1345 specified filename. <code class="directive"><Files></code>
1346 sections are processed in the order they appear in the
1347 configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
1348 <code>.htaccess</code> files are read, but before <code class="directive"><a href="#location"><Location></a></code> sections. Note
1349 that <code class="directive"><Files></code> can be nested
1350 inside <code class="directive"><a href="#directory"><Directory></a></code> sections to restrict the
1351 portion of the filesystem they apply to.</p>
1353 <p>The <var>filename</var> argument should include a filename, or
1354 a wild-card string, where <code>?</code> matches any single character,
1355 and <code>*</code> matches any sequences of characters.
1356 <a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
1357 can also be used, with the addition of the
1358 <code>~</code> character. For example:</p>
1360 <div class="example"><p><code>
1361 <Files ~ "\.(gif|jpe?g|png)$">
1364 <p>would match most common Internet graphics formats. <code class="directive"><a href="#filesmatch"><FilesMatch></a></code> is preferred,
1367 <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
1368 <code>.htaccess</code> files. This allows users to control access to
1369 their own files, at a file-by-file level.</p>
1374 <li><a href="../sections.html">How <Directory>, <Location>
1375 and <Files> sections work</a> for an explanation of how these
1376 different sections are combined when a request is received</li>
1379 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1380 <div class="directive-section"><h2><a name="FilesMatch" id="FilesMatch"><FilesMatch></a> <a name="filesmatch" id="filesmatch">Directive</a></h2>
1381 <table class="directive">
1382 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to regular-expression matched
1384 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><FilesMatch <var>regex</var>> ... </FilesMatch></code></td></tr>
1385 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1386 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1387 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1388 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1390 <p>The <code class="directive"><FilesMatch></code> directive
1391 limits the scope of the enclosed directives by filename, just as the
1392 <code class="directive"><a href="#files"><Files></a></code> directive
1393 does. However, it accepts a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular
1394 expression</a>. For example:</p>
1396 <div class="example"><p><code>
1397 <FilesMatch "\.(gif|jpe?g|png)$">
1400 <p>would match most common Internet graphics formats.</p>
1404 <li><a href="../sections.html">How <Directory>, <Location>
1405 and <Files> sections work</a> for an explanation of how these
1406 different sections are combined when a request is received</li>
1409 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1410 <div class="directive-section"><h2><a name="ForceType" id="ForceType">ForceType</a> <a name="forcetype" id="forcetype">Directive</a></h2>
1411 <table class="directive">
1412 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be served with the specified
1413 media type in the HTTP Content-Type header field</td></tr>
1414 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ForceType <var>media-type</var>|None</code></td></tr>
1415 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
1416 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
1417 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1418 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1419 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Moved to the core in Apache httpd 2.0</td></tr>
1421 <p>When placed into an <code>.htaccess</code> file or a
1422 <code class="directive"><a href="#directory"><Directory></a></code>, or
1423 <code class="directive"><a href="#location"><Location></a></code> or
1424 <code class="directive"><a href="#files"><Files></a></code>
1425 section, this directive forces all matching files to be served
1426 with the content type identification given by
1427 <var>media-type</var>. For example, if you had a directory full of
1428 GIF files, but did not want to label them all with <code>.gif</code>,
1429 you might want to use:</p>
1431 <div class="example"><p><code>
1435 <p>Note that this directive overrides other indirect media type
1436 associations defined in mime.types or via the
1437 <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code>.</p>
1439 <p>You can also override more general
1440 <code class="directive">ForceType</code> settings
1441 by using the value of <code>None</code>:</p>
1443 <div class="example"><p><code>
1444 # force all files to be image/gif:<br />
1445 <Location /images><br />
1446 <span class="indent">
1447 ForceType image/gif<br />
1449 </Location><br />
1451 # but normal mime-type associations here:<br />
1452 <Location /images/mixed><br />
1453 <span class="indent">
1454 ForceType None<br />
1459 <p>This directive primarily overrides the content types generated for
1460 static files served out of the filesystem. For resources other than
1461 static files, where the generator of the response typically specifies
1462 a Content-Type, this directive has no effect.</p>
1466 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1467 <div class="directive-section"><h2><a name="HostnameLookups" id="HostnameLookups">HostnameLookups</a> <a name="hostnamelookups" id="hostnamelookups">Directive</a></h2>
1468 <table class="directive">
1469 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables DNS lookups on client IP addresses</td></tr>
1470 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>HostnameLookups On|Off|Double</code></td></tr>
1471 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>HostnameLookups Off</code></td></tr>
1472 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1473 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1474 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1476 <p>This directive enables DNS lookups so that host names can be
1477 logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
1478 The value <code>Double</code> refers to doing double-reverse
1479 DNS lookup. That is, after a reverse lookup is performed, a forward
1480 lookup is then performed on that result. At least one of the IP
1481 addresses in the forward lookup must match the original
1482 address. (In "tcpwrappers" terminology this is called
1483 <code>PARANOID</code>.)</p>
1485 <p>Regardless of the setting, when <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code> is
1486 used for controlling access by hostname, a double reverse lookup
1487 will be performed. This is necessary for security. Note that the
1488 result of this double-reverse isn't generally available unless you
1489 set <code>HostnameLookups Double</code>. For example, if only
1490 <code>HostnameLookups On</code> and a request is made to an object
1491 that is protected by hostname restrictions, regardless of whether
1492 the double-reverse fails or not, CGIs will still be passed the
1493 single-reverse result in <code>REMOTE_HOST</code>.</p>
1495 <p>The default is <code>Off</code> in order to save the network
1496 traffic for those sites that don't truly need the reverse
1497 lookups done. It is also better for the end users because they
1498 don't have to suffer the extra latency that a lookup entails.
1499 Heavily loaded sites should leave this directive
1500 <code>Off</code>, since DNS lookups can take considerable
1501 amounts of time. The utility <code class="program"><a href="../programs/logresolve.html">logresolve</a></code>, compiled by
1502 default to the <code>bin</code> subdirectory of your installation
1503 directory, can be used to look up host names from logged IP addresses
1507 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1508 <div class="directive-section"><h2><a name="If" id="If"><If></a> <a name="if" id="if">Directive</a></h2>
1509 <table class="directive">
1510 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only if a condition is
1511 satisfied by a request at runtime</td></tr>
1512 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><If <var>expression</var>> ... </If></code></td></tr>
1513 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1514 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1515 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1516 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1518 <p>The <code class="directive"><If></code> directive
1519 evaluates an expression at runtime, and applies the enclosed
1520 directives if and only if the expression evaluates to true.
1523 <div class="example"><p><code>
1524 <If "$req{Host} = ''">
1527 <p>would match HTTP/1.0 requests without a <var>Host:</var> header.</p>
1529 <p>You may compare the value of any variable in the request headers
1530 ($req), response headers ($resp) or environment ($env) in your
1533 <p>Apart from <code>=</code>, <code>If</code> can use the <code>IN</code>
1534 operator to compare if the expression is in a given range:</p>
1536 <div class="example"><p><code>
1537 <If %{REQUEST_METHOD} IN GET,HEAD,OPTIONS>
1543 <li><a href="../sections.html">How <Directory>, <Location>,
1544 <Files> sections work</a> for an explanation of how these
1545 different sections are combined when a request is received.
1546 <code class="directive"><If></code> has the same precedence
1547 and usage as <code class="directive"><Files></code></li>
1550 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1551 <div class="directive-section"><h2><a name="IfDefine" id="IfDefine"><IfDefine></a> <a name="ifdefine" id="ifdefine">Directive</a></h2>
1552 <table class="directive">
1553 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that will be processed only
1554 if a test is true at startup</td></tr>
1555 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfDefine [!]<var>parameter-name</var>> ...
1556 </IfDefine></code></td></tr>
1557 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1558 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1559 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1560 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1562 <p>The <code><IfDefine <var>test</var>>...</IfDefine>
1563 </code> section is used to mark directives that are conditional. The
1564 directives within an <code class="directive"><IfDefine></code>
1565 section are only processed if the <var>test</var> is true. If <var>
1566 test</var> is false, everything between the start and end markers is
1569 <p>The <var>test</var> in the <code class="directive"><IfDefine></code> section directive can be one of two forms:</p>
1572 <li><var>parameter-name</var></li>
1574 <li><code>!</code><var>parameter-name</var></li>
1577 <p>In the former case, the directives between the start and end
1578 markers are only processed if the parameter named
1579 <var>parameter-name</var> is defined. The second format reverses
1580 the test, and only processes the directives if
1581 <var>parameter-name</var> is <strong>not</strong> defined.</p>
1583 <p>The <var>parameter-name</var> argument is a define as given on the
1584 <code class="program"><a href="../programs/httpd.html">httpd</a></code> command line via <code>-D<var>parameter</var>
1585 </code> at the time the server was started or by the <code class="directive"><a href="#define">Define</a></code> directive.</p>
1587 <p><code class="directive"><IfDefine></code> sections are
1588 nest-able, which can be used to implement simple
1589 multiple-parameter tests. Example:</p>
1591 <div class="example"><p><code>
1592 httpd -DReverseProxy -DUseCache -DMemCache ...<br />
1595 <IfDefine ReverseProxy><br />
1596 <span class="indent">
1597 LoadModule proxy_module modules/mod_proxy.so<br />
1598 LoadModule proxy_http_module modules/mod_proxy_http.so<br />
1599 <IfDefine UseCache><br />
1600 <span class="indent">
1601 LoadModule cache_module modules/mod_cache.so<br />
1602 <IfDefine MemCache><br />
1603 <span class="indent">
1604 LoadModule mem_cache_module modules/mod_mem_cache.so<br />
1606 </IfDefine><br />
1607 <IfDefine !MemCache><br />
1608 <span class="indent">
1609 LoadModule disk_cache_module modules/mod_disk_cache.so<br />
1619 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1620 <div class="directive-section"><h2><a name="IfModule" id="IfModule"><IfModule></a> <a name="ifmodule" id="ifmodule">Directive</a></h2>
1621 <table class="directive">
1622 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that are processed conditional on the
1623 presence or absence of a specific module</td></tr>
1624 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><IfModule [!]<var>module-file</var>|<var>module-identifier</var>> ...
1625 </IfModule></code></td></tr>
1626 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1627 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1628 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1629 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1630 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Module identifiers are available in version 2.1 and
1633 <p>The <code><IfModule <var>test</var>>...</IfModule></code>
1634 section is used to mark directives that are conditional on the presence of
1635 a specific module. The directives within an <code class="directive"><IfModule></code> section are only processed if the <var>test</var>
1636 is true. If <var>test</var> is false, everything between the start and
1637 end markers is ignored.</p>
1639 <p>The <var>test</var> in the <code class="directive"><IfModule></code> section directive can be one of two forms:</p>
1642 <li><var>module</var></li>
1644 <li>!<var>module</var></li>
1647 <p>In the former case, the directives between the start and end
1648 markers are only processed if the module named <var>module</var>
1649 is included in Apache httpd -- either compiled in or
1650 dynamically loaded using <code class="directive"><a href="../mod/mod_so.html#loadmodule">LoadModule</a></code>. The second format reverses the test,
1651 and only processes the directives if <var>module</var> is
1652 <strong>not</strong> included.</p>
1654 <p>The <var>module</var> argument can be either the module identifier or
1655 the file name of the module, at the time it was compiled. For example,
1656 <code>rewrite_module</code> is the identifier and
1657 <code>mod_rewrite.c</code> is the file name. If a module consists of
1658 several source files, use the name of the file containing the string
1659 <code>STANDARD20_MODULE_STUFF</code>.</p>
1661 <p><code class="directive"><IfModule></code> sections are
1662 nest-able, which can be used to implement simple multiple-module
1665 <div class="note">This section should only be used if you need to have one
1666 configuration file that works whether or not a specific module
1667 is available. In normal operation, directives need not be
1668 placed in <code class="directive"><IfModule></code>
1672 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1673 <div class="directive-section"><h2><a name="Include" id="Include">Include</a> <a name="include" id="include">Directive</a></h2>
1674 <table class="directive">
1675 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
1676 the server configuration files</td></tr>
1677 <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>
1678 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1679 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1680 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1681 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Wildcard matching available in 2.0.41 and later, directory
1682 wildcard matching available in 2.3.6 and later</td></tr>
1684 <p>This directive allows inclusion of other configuration files
1685 from within the server configuration files.</p>
1687 <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used
1688 in the filename or directory parts of the path to include several files
1689 at once, in alphabetical order. In addition, if
1690 <code class="directive">Include</code> points to a directory, rather than a file,
1691 Apache httpd will read all files in that directory and any subdirectory.
1692 However, including entire directories is not recommended, because it is
1693 easy to accidentally leave temporary files in a directory that can cause
1694 <code class="program"><a href="../programs/httpd.html">httpd</a></code> to fail. Instead, we encourage you to use the
1695 wildcard syntax shown below, to include files that match a particular
1696 pattern, such as *.conf, for example.</p>
1698 <p>When a wildcard is specified for a <strong>file</strong> component of
1699 the path, and no file matches the wildcard, the
1700 <code class="directive"><a href="#include">Include</a></code>
1701 directive will be <strong>silently ignored</strong>. When a wildcard is
1702 specified for a <strong>directory</strong> component of the path, and
1703 no directory matches the wildcard, the
1704 <code class="directive"><a href="#include">Include</a></code> directive will
1705 <strong>fail with an error</strong> saying the directory cannot be found.
1708 <p>For further control over the behaviour of the server when no files or
1709 directories match, prefix the path with the modifiers <var>optional</var>
1710 or <var>strict</var>. If <var>optional</var> is specified, any wildcard
1711 file or directory that does not match will be silently ignored. If
1712 <var>strict</var> is specified, any wildcard file or directory that does
1713 not match at least one file will cause server startup to fail.</p>
1715 <p>When a directory or file component of the path is
1716 specified exactly, and that directory or file does not exist,
1717 <code class="directive"><a href="#include">Include</a></code> directive will fail with an
1718 error saying the file or directory cannot be found.</p>
1720 <p>The file path specified may be an absolute path, or may be relative
1721 to the <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory.</p>
1725 <div class="example"><p><code>
1726 Include /usr/local/apache2/conf/ssl.conf<br />
1727 Include /usr/local/apache2/conf/vhosts/*.conf
1730 <p>Or, providing paths relative to your <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory:</p>
1732 <div class="example"><p><code>
1733 Include conf/ssl.conf<br />
1734 Include conf/vhosts/*.conf
1737 <p>Wildcards may be included in the directory or file portion of the
1738 path. In the following example, the server will fail to load if no
1739 directories match conf/vhosts/*, but will load successfully if no
1740 files match *.conf.</p>
1742 <div class="example"><p><code>
1743 Include conf/vhosts/*/vhost.conf<br />
1744 Include conf/vhosts/*/*.conf
1747 <p>In this example, the server will fail to load if either
1748 conf/vhosts/* matches no directories, or if *.conf matches no files:</p>
1750 <div class="example"><p><code>
1751 Include strict conf/vhosts/*/*.conf
1754 <p>In this example, the server load successfully if either conf/vhosts/*
1755 matches no directories, or if *.conf matches no files:</p>
1757 <div class="example"><p><code>
1758 Include optional conf/vhosts/*/*.conf
1764 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
1767 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1768 <div class="directive-section"><h2><a name="KeepAlive" id="KeepAlive">KeepAlive</a> <a name="keepalive" id="keepalive">Directive</a></h2>
1769 <table class="directive">
1770 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables HTTP persistent connections</td></tr>
1771 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAlive On|Off</code></td></tr>
1772 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAlive On</code></td></tr>
1773 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1774 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1775 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1777 <p>The Keep-Alive extension to HTTP/1.0 and the persistent
1778 connection feature of HTTP/1.1 provide long-lived HTTP sessions
1779 which allow multiple requests to be sent over the same TCP
1780 connection. In some cases this has been shown to result in an
1781 almost 50% speedup in latency times for HTML documents with
1782 many images. To enable Keep-Alive connections, set
1783 <code>KeepAlive On</code>.</p>
1785 <p>For HTTP/1.0 clients, Keep-Alive connections will only be
1786 used if they are specifically requested by a client. In
1787 addition, a Keep-Alive connection with an HTTP/1.0 client can
1788 only be used when the length of the content is known in
1789 advance. This implies that dynamic content such as CGI output,
1790 SSI pages, and server-generated directory listings will
1791 generally not use Keep-Alive connections to HTTP/1.0 clients.
1792 For HTTP/1.1 clients, persistent connections are the default
1793 unless otherwise specified. If the client requests it, chunked
1794 encoding will be used in order to send content of unknown
1795 length over persistent connections.</p>
1797 <p>When a client uses a Keep-Alive connection it will be counted
1798 as a single "request" for the <code class="directive"><a href="../mod/mpm_common.html#maxrequestsperchild">MaxRequestsPerChild</a></code> directive, regardless
1799 of how many requests are sent using the connection.</p>
1803 <li><code class="directive"><a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></code></li>
1806 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1807 <div class="directive-section"><h2><a name="KeepAliveTimeout" id="KeepAliveTimeout">KeepAliveTimeout</a> <a name="keepalivetimeout" id="keepalivetimeout">Directive</a></h2>
1808 <table class="directive">
1809 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for subsequent
1810 requests on a persistent connection</td></tr>
1811 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAliveTimeout <var>num</var>[ms]</code></td></tr>
1812 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAliveTimeout 5</code></td></tr>
1813 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1814 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1815 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1816 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Specifying a value in milliseconds is available in
1817 Apache httpd 2.3.2 and later</td></tr>
1819 <p>The number of seconds Apache httpd will wait for a subsequent
1820 request before closing the connection. By adding a postfix of ms the
1821 timeout can be also set in milliseconds. Once a request has been
1822 received, the timeout value specified by the
1823 <code class="directive"><a href="#timeout">Timeout</a></code> directive applies.</p>
1825 <p>Setting <code class="directive">KeepAliveTimeout</code> to a high value
1826 may cause performance problems in heavily loaded servers. The
1827 higher the timeout, the more server processes will be kept
1828 occupied waiting on connections with idle clients.</p>
1830 <p>In a name-based virtual host context, the value of the first
1831 defined virtual host (the default host) in a set of <code class="directive"><a href="#namevirtualhost">NameVirtualHost</a></code> will be used.
1832 The other values will be ignored.</p>
1835 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1836 <div class="directive-section"><h2><a name="Limit" id="Limit"><Limit></a> <a name="limit" id="limit">Directive</a></h2>
1837 <table class="directive">
1838 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict enclosed access controls to only certain HTTP
1840 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Limit <var>method</var> [<var>method</var>] ... > ...
1841 </Limit></code></td></tr>
1842 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
1843 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
1844 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1845 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1847 <p>Access controls are normally effective for
1848 <strong>all</strong> access methods, and this is the usual
1849 desired behavior. <strong>In the general case, access control
1850 directives should not be placed within a
1851 <code class="directive"><Limit></code> section.</strong></p>
1853 <p>The purpose of the <code class="directive"><Limit></code>
1854 directive is to restrict the effect of the access controls to the
1855 nominated HTTP methods. For all other methods, the access
1856 restrictions that are enclosed in the <code class="directive"><Limit></code> bracket <strong>will have no
1857 effect</strong>. The following example applies the access control
1858 only to the methods <code>POST</code>, <code>PUT</code>, and
1859 <code>DELETE</code>, leaving all other methods unprotected:</p>
1861 <div class="example"><p><code>
1862 <Limit POST PUT DELETE><br />
1863 <span class="indent">
1864 Require valid-user<br />
1869 <p>The method names listed can be one or more of: <code>GET</code>,
1870 <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
1871 <code>CONNECT</code>, <code>OPTIONS</code>,
1872 <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
1873 <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
1874 <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
1875 case-sensitive.</strong> If <code>GET</code> is used it will also
1876 restrict <code>HEAD</code> requests. The <code>TRACE</code> method
1877 cannot be limited (see <code class="directive"><a href="#traceenable">TraceEnable</a></code>).</p>
1879 <div class="warning">A <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section should always be
1880 used in preference to a <code class="directive"><Limit></code>
1881 section when restricting access, since a <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> section provides protection
1882 against arbitrary methods.</div>
1884 <p>The <code class="directive"><Limit></code> and
1885 <code class="directive"><a href="#limitexcept"><LimitExcept></a></code>
1886 directives may be nested. In this case, each successive level of
1887 <code class="directive"><Limit></code> or <code class="directive"><a href="#limitexcept"><LimitExcept></a></code> directives must
1888 further restrict the set of methods to which access controls apply.</p>
1890 <div class="warning">When using
1891 <code class="directive"><Limit></code> or
1892 <code class="directive"><LimitExcept></code> directives with
1893 the <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directive,
1894 note that the first <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code>
1895 to succeed authorizes the request, regardless of the presence of other
1896 <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code> directives.</div>
1898 <p>For example, given the following configuration, all users will
1899 be authorized for <code>POST</code> requests, and the
1900 <code>Require group editors</code> directive will be ignored
1903 <div class="example"><p><code>
1904 <LimitExcept GET>
1905 <span class="indent">
1908 </LimitExcept><br />
1910 <span class="indent">
1911 Require group editors
1917 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1918 <div class="directive-section"><h2><a name="LimitExcept" id="LimitExcept"><LimitExcept></a> <a name="limitexcept" id="limitexcept">Directive</a></h2>
1919 <table class="directive">
1920 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict access controls to all HTTP methods
1921 except the named ones</td></tr>
1922 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LimitExcept <var>method</var> [<var>method</var>] ... > ...
1923 </LimitExcept></code></td></tr>
1924 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
1925 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig, Limit</td></tr>
1926 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1927 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1929 <p><code class="directive"><LimitExcept></code> and
1930 <code></LimitExcept></code> are used to enclose
1931 a group of access control directives which will then apply to any
1932 HTTP access method <strong>not</strong> listed in the arguments;
1933 i.e., it is the opposite of a <code class="directive"><a href="#limit"><Limit></a></code> section and can be used to control
1934 both standard and nonstandard/unrecognized methods. See the
1935 documentation for <code class="directive"><a href="#limit"><Limit></a></code> for more details.</p>
1939 <div class="example"><p><code>
1940 <LimitExcept POST GET><br />
1941 <span class="indent">
1942 Require valid-user<br />
1944 </LimitExcept>
1949 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1950 <div class="directive-section"><h2><a name="LimitInternalRecursion" id="LimitInternalRecursion">LimitInternalRecursion</a> <a name="limitinternalrecursion" id="limitinternalrecursion">Directive</a></h2>
1951 <table class="directive">
1952 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine maximum number of internal redirects and nested
1953 subrequests</td></tr>
1954 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitInternalRecursion <var>number</var> [<var>number</var>]</code></td></tr>
1955 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitInternalRecursion 10</code></td></tr>
1956 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1957 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1958 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1959 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.0.47 and later</td></tr>
1961 <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
1962 redirects the original request to a CGI script. A subrequest is Apache httpd's
1963 mechanism to find out what would happen for some URI if it were requested.
1964 For example, <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> uses subrequests to look for the
1965 files listed in the <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
1968 <p><code class="directive">LimitInternalRecursion</code> prevents the server
1969 from crashing when entering an infinite loop of internal redirects or
1970 subrequests. Such loops are usually caused by misconfigurations.</p>
1972 <p>The directive stores two different limits, which are evaluated on
1973 per-request basis. The first <var>number</var> is the maximum number of
1974 internal redirects, that may follow each other. The second <var>number</var>
1975 determines, how deep subrequests may be nested. If you specify only one
1976 <var>number</var>, it will be assigned to both limits.</p>
1978 <div class="example"><h3>Example</h3><p><code>
1979 LimitInternalRecursion 5
1983 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1984 <div class="directive-section"><h2><a name="LimitRequestBody" id="LimitRequestBody">LimitRequestBody</a> <a name="limitrequestbody" id="limitrequestbody">Directive</a></h2>
1985 <table class="directive">
1986 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restricts the total size of the HTTP request body sent
1987 from the client</td></tr>
1988 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestBody <var>bytes</var></code></td></tr>
1989 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestBody 0</code></td></tr>
1990 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
1991 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
1992 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
1993 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
1995 <p>This directive specifies the number of <var>bytes</var> from 0
1996 (meaning unlimited) to 2147483647 (2GB) that are allowed in a
1999 <p>The <code class="directive">LimitRequestBody</code> directive allows
2000 the user to set a limit on the allowed size of an HTTP request
2001 message body within the context in which the directive is given
2002 (server, per-directory, per-file or per-location). If the client
2003 request exceeds that limit, the server will return an error
2004 response instead of servicing the request. The size of a normal
2005 request message body will vary greatly depending on the nature of
2006 the resource and the methods allowed on that resource. CGI scripts
2007 typically use the message body for retrieving form information.
2008 Implementations of the <code>PUT</code> method will require
2009 a value at least as large as any representation that the server
2010 wishes to accept for that resource.</p>
2012 <p>This directive gives the server administrator greater
2013 control over abnormal client request behavior, which may be
2014 useful for avoiding some forms of denial-of-service
2017 <p>If, for example, you are permitting file upload to a particular
2018 location, and wish to limit the size of the uploaded file to 100K,
2019 you might use the following directive:</p>
2021 <div class="example"><p><code>
2022 LimitRequestBody 102400
2027 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2028 <div class="directive-section"><h2><a name="LimitRequestFields" id="LimitRequestFields">LimitRequestFields</a> <a name="limitrequestfields" id="limitrequestfields">Directive</a></h2>
2029 <table class="directive">
2030 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of HTTP request header fields that
2031 will be accepted from the client</td></tr>
2032 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFields <var>number</var></code></td></tr>
2033 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFields 100</code></td></tr>
2034 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
2035 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2036 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2038 <p><var>Number</var> is an integer from 0 (meaning unlimited) to
2039 32767. The default value is defined by the compile-time
2040 constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
2043 <p>The <code class="directive">LimitRequestFields</code> directive allows
2044 the server administrator to modify the limit on the number of
2045 request header fields allowed in an HTTP request. A server needs
2046 this value to be larger than the number of fields that a normal
2047 client request might include. The number of request header fields
2048 used by a client rarely exceeds 20, but this may vary among
2049 different client implementations, often depending upon the extent
2050 to which a user has configured their browser to support detailed
2051 content negotiation. Optional HTTP extensions are often expressed
2052 using request header fields.</p>
2054 <p>This directive gives the server administrator greater
2055 control over abnormal client request behavior, which may be
2056 useful for avoiding some forms of denial-of-service attacks.
2057 The value should be increased if normal clients see an error
2058 response from the server that indicates too many fields were
2059 sent in the request.</p>
2063 <div class="example"><p><code>
2064 LimitRequestFields 50
2069 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2070 <div class="directive-section"><h2><a name="LimitRequestFieldSize" id="LimitRequestFieldSize">LimitRequestFieldSize</a> <a name="limitrequestfieldsize" id="limitrequestfieldsize">Directive</a></h2>
2071 <table class="directive">
2072 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of the HTTP request header allowed from the
2074 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFieldSize <var>bytes</var></code></td></tr>
2075 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFieldSize 8190</code></td></tr>
2076 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
2077 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2078 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2080 <p>This directive specifies the number of <var>bytes</var>
2081 that will be allowed in an HTTP request header.</p>
2083 <p>The <code class="directive">LimitRequestFieldSize</code> directive
2084 allows the server administrator to reduce or increase the limit
2085 on the allowed size of an HTTP request header field. A server
2086 needs this value to be large enough to hold any one header field
2087 from a normal client request. The size of a normal request header
2088 field will vary greatly among different client implementations,
2089 often depending upon the extent to which a user has configured
2090 their browser to support detailed content negotiation. SPNEGO
2091 authentication headers can be up to 12392 bytes.</p>
2093 <p>This directive gives the server administrator greater
2094 control over abnormal client request behavior, which may be
2095 useful for avoiding some forms of denial-of-service attacks.</p>
2099 <div class="example"><p><code>
2100 LimitRequestFieldSize 4094
2103 <div class="note">Under normal conditions, the value should not be changed from
2108 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2109 <div class="directive-section"><h2><a name="LimitRequestLine" id="LimitRequestLine">LimitRequestLine</a> <a name="limitrequestline" id="limitrequestline">Directive</a></h2>
2110 <table class="directive">
2111 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limit the size of the HTTP request line that will be accepted
2112 from the client</td></tr>
2113 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestLine <var>bytes</var></code></td></tr>
2114 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestLine 8190</code></td></tr>
2115 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
2116 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2117 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2119 <p>This directive sets the number of <var>bytes</var> that will be
2120 allowed on the HTTP request-line.</p>
2122 <p>The <code class="directive">LimitRequestLine</code> directive allows
2123 the server administrator to reduce or increase the limit on the allowed size
2124 of a client's HTTP request-line. Since the request-line consists of the
2125 HTTP method, URI, and protocol version, the
2126 <code class="directive">LimitRequestLine</code> directive places a
2127 restriction on the length of a request-URI allowed for a request
2128 on the server. A server needs this value to be large enough to
2129 hold any of its resource names, including any information that
2130 might be passed in the query part of a <code>GET</code> request.</p>
2132 <p>This directive gives the server administrator greater
2133 control over abnormal client request behavior, which may be
2134 useful for avoiding some forms of denial-of-service attacks.</p>
2138 <div class="example"><p><code>
2139 LimitRequestLine 4094
2142 <div class="note">Under normal conditions, the value should not be changed from
2146 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2147 <div class="directive-section"><h2><a name="LimitXMLRequestBody" id="LimitXMLRequestBody">LimitXMLRequestBody</a> <a name="limitxmlrequestbody" id="limitxmlrequestbody">Directive</a></h2>
2148 <table class="directive">
2149 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of an XML-based request body</td></tr>
2150 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitXMLRequestBody <var>bytes</var></code></td></tr>
2151 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitXMLRequestBody 1000000</code></td></tr>
2152 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2153 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
2154 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2155 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2157 <p>Limit (in bytes) on maximum size of an XML-based request
2158 body. A value of <code>0</code> will disable any checking.</p>
2162 <div class="example"><p><code>
2163 LimitXMLRequestBody 0
2168 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2169 <div class="directive-section"><h2><a name="Location" id="Location"><Location></a> <a name="location" id="location">Directive</a></h2>
2170 <table class="directive">
2171 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to matching
2173 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Location
2174 <var>URL-path</var>|<var>URL</var>> ... </Location></code></td></tr>
2175 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2176 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2177 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2179 <p>The <code class="directive"><Location></code> directive
2180 limits the scope of the enclosed directives by URL. It is similar to the
2181 <code class="directive"><a href="#directory"><Directory></a></code>
2182 directive, and starts a subsection which is terminated with a
2183 <code></Location></code> directive. <code class="directive"><Location></code> sections are processed in the
2184 order they appear in the configuration file, after the <code class="directive"><a href="#directory"><Directory></a></code> sections and
2185 <code>.htaccess</code> files are read, and after the <code class="directive"><a href="#files"><Files></a></code> sections.</p>
2187 <p><code class="directive"><Location></code> sections operate
2188 completely outside the filesystem. This has several consequences.
2189 Most importantly, <code class="directive"><Location></code>
2190 directives should not be used to control access to filesystem
2191 locations. Since several different URLs may map to the same
2192 filesystem location, such access controls may by circumvented.</p>
2194 <div class="note"><h3>When to use <code class="directive"><Location></code></h3>
2196 <p>Use <code class="directive"><Location></code> to apply
2197 directives to content that lives outside the filesystem. For
2198 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
2199 <code><Location /></code>, which is an easy way to
2200 apply a configuration to the entire server.</p>
2203 <p>For all origin (non-proxy) requests, the URL to be matched is a
2204 URL-path of the form <code>/path/</code>. <em>No scheme, hostname,
2205 port, or query string may be included.</em> For proxy requests, the
2206 URL to be matched is of the form
2207 <code>scheme://servername/path</code>, and you must include the
2210 <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
2211 any single character, and <code>*</code> matches any sequences of
2212 characters. Neither wildcard character matches a / in the URL-path.</p>
2214 <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
2215 can also be used, with the addition of the <code>~</code>
2216 character. For example:</p>
2218 <div class="example"><p><code>
2219 <Location ~ "/(extra|special)/data">
2222 <p>would match URLs that contained the substring <code>/extra/data</code>
2223 or <code>/special/data</code>. The directive <code class="directive"><a href="#locationmatch"><LocationMatch></a></code> behaves
2224 identical to the regex version of <code class="directive"><Location></code>, and is preferred, for the
2225 simple reason that <code>~</code> is hard to distinguish from
2226 <code>-</code> in many fonts.</p>
2228 <p>The <code class="directive"><Location></code>
2229 functionality is especially useful when combined with the
2230 <code class="directive"><a href="#sethandler">SetHandler</a></code>
2231 directive. For example, to enable status requests, but allow them
2232 only from browsers at <code>example.com</code>, you might use:</p>
2234 <div class="example"><p><code>
2235 <Location /status><br />
2236 <span class="indent">
2237 SetHandler server-status<br />
2238 Order Deny,Allow<br />
2240 Allow from .example.com<br />
2245 <div class="note"><h3>Note about / (slash)</h3>
2246 <p>The slash character has special meaning depending on where in a
2247 URL it appears. People may be used to its behavior in the filesystem
2248 where multiple adjacent slashes are frequently collapsed to a single
2249 slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
2250 <code>/home/foo</code>). In URL-space this is not necessarily true.
2251 The <code class="directive"><a href="#locationmatch"><LocationMatch></a></code>
2252 directive and the regex version of <code class="directive"><Location></code> require you to explicitly specify multiple
2253 slashes if that is your intention.</p>
2255 <p>For example, <code><LocationMatch ^/abc></code> would match
2256 the request URL <code>/abc</code> but not the request URL <code>
2257 //abc</code>. The (non-regex) <code class="directive"><Location></code> directive behaves similarly when used for
2258 proxy requests. But when (non-regex) <code class="directive"><Location></code> is used for non-proxy requests it will
2259 implicitly match multiple slashes with a single slash. For example,
2260 if you specify <code><Location /abc/def></code> and the
2261 request is to <code>/abc//def</code> then it will match.</p>
2266 <li><a href="../sections.html">How <Directory>, <Location>
2267 and <Files> sections work</a> for an explanation of how these
2268 different sections are combined when a request is received.</li>
2269 <li><code class="directive"><a href="#locationmatch">LocationMatch</a></code></li>
2272 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2273 <div class="directive-section"><h2><a name="LocationMatch" id="LocationMatch"><LocationMatch></a> <a name="locationmatch" id="locationmatch">Directive</a></h2>
2274 <table class="directive">
2275 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to regular-expression
2276 matching URLs</td></tr>
2277 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><LocationMatch
2278 <var>regex</var>> ... </LocationMatch></code></td></tr>
2279 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2280 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2281 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2283 <p>The <code class="directive"><LocationMatch></code> directive
2284 limits the scope of the enclosed directives by URL, in an identical manner
2285 to <code class="directive"><a href="#location"><Location></a></code>. However,
2286 it takes a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
2287 as an argument instead of a simple string. For example:</p>
2289 <div class="example"><p><code>
2290 <LocationMatch "/(extra|special)/data">
2293 <p>would match URLs that contained the substring <code>/extra/data</code>
2294 or <code>/special/data</code>.</p>
2298 <li><a href="../sections.html">How <Directory>, <Location>
2299 and <Files> sections work</a> for an explanation of how these
2300 different sections are combined when a request is received</li>
2303 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2304 <div class="directive-section"><h2><a name="LogLevel" id="LogLevel">LogLevel</a> <a name="loglevel" id="loglevel">Directive</a></h2>
2305 <table class="directive">
2306 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Controls the verbosity of the ErrorLog</td></tr>
2307 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel [<var>module</var>:]<var>level</var>
2308 [<var>module</var>:<var>level</var>] ...
2310 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LogLevel warn</code></td></tr>
2311 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
2312 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2313 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2314 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Per-module and per-directory configuration is available in
2315 Apache HTTP Server 2.3.6 and later</td></tr>
2317 <p><code class="directive">LogLevel</code> adjusts the verbosity of the
2318 messages recorded in the error logs (see <code class="directive"><a href="#errorlog">ErrorLog</a></code> directive). The following
2319 <var>level</var>s are available, in order of decreasing
2322 <table class="bordered">
2325 <th><strong>Level</strong> </th>
2327 <th><strong>Description</strong> </th>
2329 <th><strong>Example</strong> </th>
2333 <td><code>emerg</code> </td>
2335 <td>Emergencies - system is unusable.</td>
2337 <td>"Child cannot open lock file. Exiting"</td>
2341 <td><code>alert</code> </td>
2343 <td>Action must be taken immediately.</td>
2345 <td>"getpwuid: couldn't determine user name from uid"</td>
2349 <td><code>crit</code> </td>
2351 <td>Critical Conditions.</td>
2353 <td>"socket: Failed to get a socket, exiting child"</td>
2357 <td><code>error</code> </td>
2359 <td>Error conditions.</td>
2361 <td>"Premature end of script headers"</td>
2365 <td><code>warn</code> </td>
2367 <td>Warning conditions.</td>
2369 <td>"child process 1234 did not exit, sending another
2374 <td><code>notice</code> </td>
2376 <td>Normal but significant condition.</td>
2378 <td>"httpd: caught SIGBUS, attempting to dump core in
2383 <td><code>info</code> </td>
2385 <td>Informational.</td>
2387 <td>"Server seems busy, (you may need to increase
2388 StartServers, or Min/MaxSpareServers)..."</td>
2392 <td><code>debug</code> </td>
2394 <td>Debug-level messages</td>
2396 <td>"Opening config file ..."</td>
2399 <td><code>trace1</code> </td>
2401 <td>Trace messages</td>
2403 <td>"proxy: FTP: control connection complete"</td>
2406 <td><code>trace2</code> </td>
2408 <td>Trace messages</td>
2410 <td>"proxy: CONNECT: sending the CONNECT request to the remote proxy"</td>
2413 <td><code>trace3</code> </td>
2415 <td>Trace messages</td>
2417 <td>"openssl: Handshake: start"</td>
2420 <td><code>trace4</code> </td>
2422 <td>Trace messages</td>
2424 <td>"read from buffered SSL brigade, mode 0, 17 bytes"</td>
2427 <td><code>trace5</code> </td>
2429 <td>Trace messages</td>
2431 <td>"map lookup FAILED: map=rewritemap key=keyname"</td>
2434 <td><code>trace6</code> </td>
2436 <td>Trace messages</td>
2438 <td>"cache lookup FAILED, forcing new map lookup"</td>
2441 <td><code>trace7</code> </td>
2443 <td>Trace messages, dumping large amounts of data</td>
2445 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2448 <td><code>trace8</code> </td>
2450 <td>Trace messages, dumping large amounts of data</td>
2452 <td>"| 0000: 02 23 44 30 13 40 ac 34 df 3d bf 9a 19 49 39 15 |"</td>
2456 <p>When a particular level is specified, messages from all
2457 other levels of higher significance will be reported as well.
2458 <em>E.g.</em>, when <code>LogLevel info</code> is specified,
2459 then messages with log levels of <code>notice</code> and
2460 <code>warn</code> will also be posted.</p>
2462 <p>Using a level of at least <code>crit</code> is
2467 <div class="example"><p><code>
2471 <div class="note"><h3>Note</h3>
2472 <p>When logging to a regular file messages of the level
2473 <code>notice</code> cannot be suppressed and thus are always
2474 logged. However, this doesn't apply when logging is done
2475 using <code>syslog</code>.</p>
2478 <p>Specifying a level without a module name will reset the level
2479 for all modules to that level. Specifying a level with a module
2480 name will set the level for that module only. It is possible to
2481 use the module source file name, the module identifier, or the
2482 module identifier with the trailing <code>_module</code> omitted
2483 as module specification. This means the following three specifications
2486 <div class="example"><p><code>
2487 LogLevel info ssl:warn<br />
2488 LogLevel info mod_ssl.c:warn<br />
2489 LogLevel info ssl_module:warn<br />
2492 <p>It is also possible to change the level per directory:</p>
2494 <div class="example"><p><code>
2496 <Directory /usr/local/apache/htdocs/app><br />
2497 LogLevel debug<br />
2502 Per directory loglevel configuration only affects messages that are
2503 logged after the request has been parsed and that are associated with
2504 the request. Log messages which are associated with the connection or
2505 the server are not affected.
2509 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2510 <div class="directive-section"><h2><a name="MaxKeepAliveRequests" id="MaxKeepAliveRequests">MaxKeepAliveRequests</a> <a name="maxkeepaliverequests" id="maxkeepaliverequests">Directive</a></h2>
2511 <table class="directive">
2512 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of requests allowed on a persistent
2513 connection</td></tr>
2514 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxKeepAliveRequests <var>number</var></code></td></tr>
2515 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxKeepAliveRequests 100</code></td></tr>
2516 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
2517 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2518 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2520 <p>The <code class="directive">MaxKeepAliveRequests</code> directive
2521 limits the number of requests allowed per connection when
2522 <code class="directive"><a href="#keepalive">KeepAlive</a></code> is on. If it is
2523 set to <code>0</code>, unlimited requests will be allowed. We
2524 recommend that this setting be kept to a high value for maximum
2525 server performance.</p>
2529 <div class="example"><p><code>
2530 MaxKeepAliveRequests 500
2534 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2535 <div class="directive-section"><h2><a name="Mutex" id="Mutex">Mutex</a> <a name="mutex" id="mutex">Directive</a></h2>
2536 <table class="directive">
2537 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures mutex mechanism and lock file directory for all
2538 or specified mutexes</td></tr>
2539 <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>
2540 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Mutex default</code></td></tr>
2541 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
2542 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2543 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2544 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.3.4 and later</td></tr>
2546 <p>The <code class="directive">Mutex</code> directive sets the mechanism,
2547 and optionally the lock file location, that httpd and modules use
2548 to serialize access to resources. Specify <code>default</code> as
2549 the first argument to change the settings for all mutexes; specify
2550 a mutex name (see table below) as the first argument to override
2551 defaults only for that mutex.</p>
2553 <p>The <code class="directive">Mutex</code> directive is typically used in
2554 the following exceptional situations:</p>
2557 <li>change the mutex mechanism when the default mechanism selected
2558 by <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> has a functional or performance
2561 <li>change the directory used by file-based mutexes when the
2562 default directory does not support locking</li>
2565 <div class="note"><h3>Supported modules</h3>
2566 <p>This directive only configures mutexes which have been registered
2567 with the core server using the <code>ap_mutex_register()</code> API.
2568 All modules bundled with httpd support the <code class="directive">Mutex</code>
2569 directive, but third-party modules may not. Consult the documentation
2570 of the third-party module, which must indicate the mutex name(s) which
2571 can be configured if this directive is supported.</p>
2574 <p>The following mutex <em>mechanisms</em> are available:</p>
2576 <li><code>default | yes</code>
2577 <p>This selects the default locking implementation, as determined by
2578 <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a>. The default locking implementation can
2579 be displayed by running <code class="program"><a href="../programs/httpd.html">httpd</a></code> with the
2580 <code>-V</code> option.</p></li>
2582 <li><code>none | no</code>
2583 <p>This effectively disables the mutex, and is only allowed for a
2584 mutex if the module indicates that it is a valid choice. Consult the
2585 module documentation for more information.</p></li>
2587 <li><code>posixsem</code>
2588 <p>This is a mutex variant based on a Posix semaphore.</p>
2590 <div class="warning"><h3>Warning</h3>
2591 <p>The semaphore ownership is not recovered if a thread in the process
2592 holding the mutex segfaults, resulting in a hang of the web server.</p>
2596 <li><code>sysvsem</code>
2597 <p>This is a mutex variant based on a SystemV IPC semaphore.</p>
2599 <div class="warning"><h3>Warning</h3>
2600 <p>It is possible to "leak" SysV semaphores if processes crash
2601 before the semaphore is removed.</p>
2604 <div class="warning"><h3>Security</h3>
2605 <p>The semaphore API allows for a denial of service attack by any
2606 CGIs running under the same uid as the webserver (<em>i.e.</em>,
2607 all CGIs, unless you use something like <code class="program"><a href="../programs/suexec.html">suexec</a></code>
2608 or <code>cgiwrapper</code>).</p>
2612 <li><code>sem</code>
2613 <p>This selects the "best" available semaphore implementation, choosing
2614 between Posix and SystemV IPC semaphores, in that order.</p></li>
2616 <li><code>pthread</code>
2617 <p>This is a mutex variant based on cross-process Posix thread
2620 <div class="warning"><h3>Warning</h3>
2621 <p>On most systems, if a child process terminates abnormally while
2622 holding a mutex that uses this implementation, the server will deadlock
2623 and stop responding to requests. When this occurs, the server will
2624 require a manual restart to recover.</p>
2625 <p>Solaris is a notable exception as it provides a mechanism which
2626 usually allows the mutex to be recovered after a child process
2627 terminates abnormally while holding a mutex.</p>
2628 <p>If your system implements the
2629 <code>pthread_mutexattr_setrobust_np()</code> function, you may be able
2630 to use the <code>pthread</code> option safely.</p>
2634 <li><code>fcntl:/path/to/mutex</code>
2635 <p>This is a mutex variant where a physical (lock-)file and the
2636 <code>fcntl()</code> function are used as the mutex.</p>
2638 <div class="warning"><h3>Warning</h3>
2639 <p>When multiple mutexes based on this mechanism are used within
2640 multi-threaded, multi-process environments, deadlock errors (EDEADLK)
2641 can be reported for valid mutex operations if <code>fcntl()</code>
2642 is not thread-aware, such as on Solaris.</p>
2646 <li><code>flock:/path/to/mutex</code>
2647 <p>This is similar to the <code>fcntl:/path/to/mutex</code> method
2648 with the exception that the <code>flock()</code> function is used to
2649 provide file locking.</p></li>
2651 <li><code>file:/path/to/mutex</code>
2652 <p>This selects the "best" available file locking implementation,
2653 choosing between <code>fcntl</code> and <code>flock</code>, in that
2657 <p>Most mechanisms are only available on selected platforms, where the
2658 underlying platform and <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a> support it. Mechanisms
2659 which aren't available on all platforms are <em>posixsem</em>,
2660 <em>sysvsem</em>, <em>sem</em>, <em>pthread</em>, <em>fcntl</em>,
2661 <em>flock</em>, and <em>file</em>.</p>
2663 <p>With the file-based mechanisms <em>fcntl</em> and <em>flock</em>,
2664 the path, if provided, is a directory where the lock file will be created.
2665 The default directory is httpd's run-time file directory relative to
2666 <code class="directive"><a href="#serverroot">ServerRoot</a></code>. Always use a local disk
2667 filesystem for <code>/path/to/mutex</code> and never a directory residing
2668 on a NFS- or AFS-filesystem. The basename of the file will be the mutex
2669 type, an optional instance string provided by the module, and unless the
2670 <code>OmitPID</code> keyword is specified, the process id of the httpd
2671 parent process will be appended to to make the file name unique, avoiding
2672 conflicts when multiple httpd instances share a lock file directory. For
2673 example, if the mutex name is <code>mpm-accept</code> and the lock file
2674 directory is <code>/var/httpd/locks</code>, the lock file name for the
2675 httpd instance with parent process id 12345 would be
2676 <code>/var/httpd/locks/mpm-accept.12345</code>.</p>
2678 <div class="warning"><h3>Security</h3>
2679 <p>It is best to <em>avoid</em> putting mutex files in a world-writable
2680 directory such as <code>/var/tmp</code> because someone could create
2681 a denial of service attack and prevent the server from starting by
2682 creating a lockfile with the same name as the one the server will try
2686 <p>The following table documents the names of mutexes used by httpd
2687 and bundled modules.</p>
2689 <table class="bordered"><tr class="header">
2692 <th>Protected resource</th>
2695 <td><code>mpm-accept</code></td>
2696 <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>
2697 <td>incoming connections, to avoid the thundering herd problem;
2698 for more information, refer to the
2699 <a href="../misc/perf-tuning.html">performance tuning</a>
2703 <td><code>authdigest-client</code></td>
2704 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
2705 <td>client list in shared memory</td>
2708 <td><code>authdigest-opaque</code></td>
2709 <td><code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code></td>
2710 <td>counter in shared memory</td>
2713 <td><code>ldap-cache</code></td>
2714 <td><code class="module"><a href="../mod/mod_ldap.html">mod_ldap</a></code></td>
2715 <td>LDAP result cache</td>
2718 <td><code>rewrite-map</code></td>
2719 <td><code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code></td>
2720 <td>communication with external mapping programs, to avoid
2721 intermixed I/O from multiple requests</td>
2724 <td><code>ssl-cache</code></td>
2725 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
2726 <td>SSL session cache</td>
2729 <td><code>ssl-stapling</code></td>
2730 <td><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></td>
2731 <td>OCSP stapling response cache</td>
2734 <td><code>watchdog-callback</code></td>
2735 <td><code class="module"><a href="../mod/mod_watchdog.html">mod_watchdog</a></code></td>
2736 <td>callback function of a particular client module</td>
2740 <p>The <code>OmitPID</code> keyword suppresses the addition of the httpd
2741 parent process id from the lock file name.</p>
2743 <p>In the following example, the mutex mechanism for the MPM accept
2744 mutex will be changed from the compiled-in default to <code>fcntl</code>,
2745 with the associated lock file created in directory
2746 <code>/var/httpd/locks</code>. The mutex mechanism for all other mutexes
2747 will be changed from the compiled-in default to <code>sysvsem</code>.</p>
2749 <div class="example"><p><code>
2750 Mutex default sysvsem<br />
2751 Mutex mpm-accept fcntl:/var/httpd/locks
2755 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2756 <div class="directive-section"><h2><a name="NameVirtualHost" id="NameVirtualHost">NameVirtualHost</a> <a name="namevirtualhost" id="namevirtualhost">Directive</a></h2>
2757 <table class="directive">
2758 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Designates an IP address for name-virtual
2760 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NameVirtualHost <var>addr</var>[:<var>port</var>]</code></td></tr>
2761 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
2762 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2763 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2766 <p>A single <code class="directive">NameVirtualHost</code> directive
2767 identifies a set of identical virtual hosts on which the server will
2768 further select from on the basis of the <em>hostname</em>
2769 requested by the client. The <code class="directive">NameVirtualHost</code>
2770 directive is a required directive if you want to configure
2771 <a href="../vhosts/">name-based virtual hosts</a>.</p>
2773 <p>This directive, and the corresponding <code class="directive">VirtualHost</code>,
2774 <em>must</em> be qualified with a port number if the server supports both HTTP
2775 and HTTPS connections.</p>
2777 <p>Although <var>addr</var> can be a hostname, it is recommended
2778 that you always use an IP address or a wildcard. A wildcard
2779 NameVirtualHost matches only virtualhosts that also have a literal wildcard
2780 as their argument.</p>
2782 <p>In cases where a firewall or other proxy receives the requests and
2783 forwards them on a different IP address to the server, you must specify the
2784 IP address of the physical interface on the machine which will be
2785 servicing the requests. </p>
2787 <p> In the example below, requests received on interface 192.0.2.1 and port 80
2788 will only select among the first two virtual hosts. Requests received on
2789 port 80 on any other interface will only select among the third and fourth
2790 virtual hosts. In the common case where the interface isn't important
2791 to the mapping, only the "*:80" NameVirtualHost and VirtualHost directives
2794 <div class="example"><p><code>
2795 NameVirtualHost 192.0.2.1:80<br />
2796 NameVirtualHost *:80<br /><br />
2798 <VirtualHost 192.0.2.1:80><br />
2799 ServerName namebased-a.example.com<br />
2800 </VirtualHost><br />
2802 <VirtualHost 192.0.2.1:80><br />
2803 Servername namebased-b.example.com<br />
2804 </VirtualHost><br />
2806 <VirtualHost *:80><br />
2807 ServerName namebased-c.example.com <br />
2808 </VirtualHost><br />
2810 <VirtualHost *:80><br />
2811 ServerName namebased-d.example.com <br />
2812 </VirtualHost><br />
2817 <p>If no matching virtual host is found, then the first listed
2818 virtual host that matches the IP address and port will be used.</p>
2821 <p>IPv6 addresses must be enclosed in square brackets, as shown
2822 in the following example:</p>
2824 <div class="example"><p><code>
2825 NameVirtualHost [2001:db8::a00:20ff:fea7:ccea]:8080
2828 <div class="note"><h3>Argument to <code class="directive"><VirtualHost></code>
2830 <p>Note that the argument to the <code class="directive"><VirtualHost></code> directive must
2831 exactly match the argument to the <code class="directive">NameVirtualHost</code> directive.</p>
2833 <div class="example"><p><code>
2834 NameVirtualHost 192.0.2.2:80<br />
2835 <VirtualHost 192.0.2.2:80><br />
2837 </VirtualHost><br />
2843 <li><a href="../vhosts/">Virtual Hosts
2844 documentation</a></li>
2847 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
2848 <div class="directive-section"><h2><a name="Options" id="Options">Options</a> <a name="options" id="options">Directive</a></h2>
2849 <table class="directive">
2850 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures what features are available in a particular
2852 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Options
2853 [+|-]<var>option</var> [[+|-]<var>option</var>] ...</code></td></tr>
2854 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Options All</code></td></tr>
2855 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
2856 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
2857 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
2858 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
2860 <p>The <code class="directive">Options</code> directive controls which
2861 server features are available in a particular directory.</p>
2863 <p><var>option</var> can be set to <code>None</code>, in which
2864 case none of the extra features are enabled, or one or more of
2868 <dt><code>All</code></dt>
2870 <dd>All options except for <code>MultiViews</code>. This is the default
2873 <dt><code>ExecCGI</code></dt>
2876 Execution of CGI scripts using <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>
2879 <dt><code>FollowSymLinks</code></dt>
2883 The server will follow symbolic links in this directory.
2885 <p>Even though the server follows the symlink it does <em>not</em>
2886 change the pathname used to match against <code class="directive"><a href="#directory"><Directory></a></code> sections.</p>
2887 <p>Note also, that this option <strong>gets ignored</strong> if set
2888 inside a <code class="directive"><a href="#location"><Location></a></code>
2890 <p>Omitting this option should not be considered a security restriction,
2891 since symlink testing is subject to race conditions that make it
2895 <dt><code>Includes</code></dt>
2898 Server-side includes provided by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
2901 <dt><code>IncludesNOEXEC</code></dt>
2905 Server-side includes are permitted, but the <code>#exec
2906 cmd</code> and <code>#exec cgi</code> are disabled. It is still
2907 possible to <code>#include virtual</code> CGI scripts from
2908 <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>ed
2911 <dt><code>Indexes</code></dt>
2914 If a URL which maps to a directory is requested, and there
2915 is no <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
2916 (<em>e.g.</em>, <code>index.html</code>) in that directory, then
2917 <code class="module"><a href="../mod/mod_autoindex.html">mod_autoindex</a></code> will return a formatted listing
2918 of the directory.</dd>
2920 <dt><code>MultiViews</code></dt>
2923 <a href="../content-negotiation.html">Content negotiated</a>
2924 "MultiViews" are allowed using
2925 <code class="module"><a href="../mod/mod_negotiation.html">mod_negotiation</a></code>.</dd>
2927 <dt><code>SymLinksIfOwnerMatch</code></dt>
2929 <dd>The server will only follow symbolic links for which the
2930 target file or directory is owned by the same user id as the
2933 <div class="note"><h3>Note</h3> <p>This option gets ignored if
2934 set inside a <code class="directive"><a href="#location"><Location></a></code> section.</p>
2935 <p>This option should not be considered a security restriction,
2936 since symlink testing is subject to race conditions that make it
2937 circumventable.</p></div>
2941 <p>Normally, if multiple <code class="directive">Options</code> could
2942 apply to a directory, then the most specific one is used and
2943 others are ignored; the options are not merged. (See <a href="../sections.html#mergin">how sections are merged</a>.)
2944 However if <em>all</em> the options on the
2945 <code class="directive">Options</code> directive are preceded by a
2946 <code>+</code> or <code>-</code> symbol, the options are
2947 merged. Any options preceded by a <code>+</code> are added to the
2948 options currently in force, and any options preceded by a
2949 <code>-</code> are removed from the options currently in
2952 <div class="warning"><h3>Warning</h3>
2953 <p>Mixing <code class="directive">Options</code> with a <code>+</code> or
2954 <code>-</code> with those without is not valid syntax, and is likely
2955 to cause unexpected results.</p>
2958 <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>
2960 <div class="example"><p><code>
2961 <Directory /web/docs><br />
2962 <span class="indent">
2963 Options Indexes FollowSymLinks<br />
2965 </Directory><br />
2967 <Directory /web/docs/spec><br />
2968 <span class="indent">
2969 Options Includes<br />
2974 <p>then only <code>Includes</code> will be set for the
2975 <code>/web/docs/spec</code> directory. However if the second
2976 <code class="directive">Options</code> directive uses the <code>+</code> and
2977 <code>-</code> symbols:</p>
2979 <div class="example"><p><code>
2980 <Directory /web/docs><br />
2981 <span class="indent">
2982 Options Indexes FollowSymLinks<br />
2984 </Directory><br />
2986 <Directory /web/docs/spec><br />
2987 <span class="indent">
2988 Options +Includes -Indexes<br />
2993 <p>then the options <code>FollowSymLinks</code> and
2994 <code>Includes</code> are set for the <code>/web/docs/spec</code>
2997 <div class="note"><h3>Note</h3>
2998 <p>Using <code>-IncludesNOEXEC</code> or
2999 <code>-Includes</code> disables server-side includes completely
3000 regardless of the previous setting.</p>
3003 <p>The default in the absence of any other settings is
3004 <code>All</code>.</p>
3007 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3008 <div class="directive-section"><h2><a name="RLimitCPU" id="RLimitCPU">RLimitCPU</a> <a name="rlimitcpu" id="rlimitcpu">Directive</a></h2>
3009 <table class="directive">
3010 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the CPU consumption of processes launched
3011 by Apache httpd children</td></tr>
3012 <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>
3013 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3014 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3015 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3016 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3017 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3019 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3020 resource limit for all processes and the second parameter sets
3021 the maximum resource limit. Either parameter can be a number,
3022 or <code>max</code> to indicate to the server that the limit should
3023 be set to the maximum allowed by the operating system
3024 configuration. Raising the maximum resource limit requires that
3025 the server is running as <code>root</code>, or in the initial startup
3028 <p>This applies to processes forked off from Apache httpd children
3029 servicing requests, not the Apache httpd children themselves. This
3030 includes CGI scripts and SSI exec commands, but not any
3031 processes forked off from the Apache httpd parent such as piped
3034 <p>CPU resource limits are expressed in seconds per
3039 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3040 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3043 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3044 <div class="directive-section"><h2><a name="RLimitMEM" id="RLimitMEM">RLimitMEM</a> <a name="rlimitmem" id="rlimitmem">Directive</a></h2>
3045 <table class="directive">
3046 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the memory consumption of processes launched
3047 by Apache httpd children</td></tr>
3048 <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>
3049 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3050 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3051 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3052 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3053 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3055 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3056 resource limit for all processes and the second parameter sets
3057 the maximum resource limit. Either parameter can be a number,
3058 or <code>max</code> to indicate to the server that the limit should
3059 be set to the maximum allowed by the operating system
3060 configuration. Raising the maximum resource limit requires that
3061 the server is running as <code>root</code>, or in the initial startup
3064 <p>This applies to processes forked off from Apache httpd children
3065 servicing requests, not the Apache httpd children themselves. This
3066 includes CGI scripts and SSI exec commands, but not any
3067 processes forked off from the Apache httpd parent such as piped
3070 <p>Memory resource limits are expressed in bytes per
3075 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3076 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
3079 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3080 <div class="directive-section"><h2><a name="RLimitNPROC" id="RLimitNPROC">RLimitNPROC</a> <a name="rlimitnproc" id="rlimitnproc">Directive</a></h2>
3081 <table class="directive">
3082 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of processes that can be launched by
3083 processes launched by Apache httpd children</td></tr>
3084 <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>
3085 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
3086 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3087 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3088 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3089 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3091 <p>Takes 1 or 2 parameters. The first parameter sets the soft
3092 resource limit for all processes and the second parameter sets
3093 the maximum resource limit. Either parameter can be a number,
3094 or <code>max</code> to indicate to the server that the limit
3095 should be set to the maximum allowed by the operating system
3096 configuration. Raising the maximum resource limit requires that
3097 the server is running as <code>root</code>, or in the initial startup
3100 <p>This applies to processes forked off from Apache httpd children
3101 servicing requests, not the Apache httpd children themselves. This
3102 includes CGI scripts and SSI exec commands, but not any
3103 processes forked off from the Apache httpd parent such as piped
3106 <p>Process limits control the number of processes per user.</p>
3108 <div class="note"><h3>Note</h3>
3109 <p>If CGI processes are <strong>not</strong> running
3110 under user ids other than the web server user id, this directive
3111 will limit the number of processes that the server itself can
3112 create. Evidence of this situation will be indicated by
3113 <strong><code>cannot fork</code></strong> messages in the
3114 <code>error_log</code>.</p>
3119 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
3120 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
3123 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3124 <div class="directive-section"><h2><a name="ScriptInterpreterSource" id="ScriptInterpreterSource">ScriptInterpreterSource</a> <a name="scriptinterpretersource" id="scriptinterpretersource">Directive</a></h2>
3125 <table class="directive">
3126 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
3128 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ScriptInterpreterSource Registry|Registry-Strict|Script</code></td></tr>
3129 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ScriptInterpreterSource Script</code></td></tr>
3130 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3131 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3132 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3133 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3134 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Win32 only;
3135 option <code>Registry-Strict</code> is available in Apache HTTP Server 2.0 and
3138 <p>This directive is used to control how Apache httpd finds the
3139 interpreter used to run CGI scripts. The default setting is
3140 <code>Script</code>. This causes Apache httpd to use the interpreter pointed to
3141 by the shebang line (first line, starting with <code>#!</code>) in the
3142 script. On Win32 systems this line usually looks like:</p>
3144 <div class="example"><p><code>
3145 #!C:/Perl/bin/perl.exe
3148 <p>or, if <code>perl</code> is in the <code>PATH</code>, simply:</p>
3150 <div class="example"><p><code>
3154 <p>Setting <code>ScriptInterpreterSource Registry</code> will
3155 cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
3156 searched using the script file extension (e.g., <code>.pl</code>) as a
3157 search key. The command defined by the registry subkey
3158 <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
3159 <code>Shell\Open\Command</code> is used to open the script file. If the
3160 registry keys cannot be found, Apache httpd falls back to the behavior of the
3161 <code>Script</code> option.</p>
3163 <div class="warning"><h3>Security</h3>
3164 <p>Be careful when using <code>ScriptInterpreterSource
3165 Registry</code> with <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>'ed directories, because
3166 Apache httpd will try to execute <strong>every</strong> file within this
3167 directory. The <code>Registry</code> setting may cause undesired
3168 program calls on files which are typically not executed. For
3169 example, the default open command on <code>.htm</code> files on
3170 most Windows systems will execute Microsoft Internet Explorer, so
3171 any HTTP request for an <code>.htm</code> file existing within the
3172 script directory would start the browser in the background on the
3173 server. This is a good way to crash your system within a minute or
3177 <p>The option <code>Registry-Strict</code> which is new in Apache HTTP Server
3178 2.0 does the same thing as <code>Registry</code> but uses only the
3179 subkey <code>Shell\ExecCGI\Command</code>. The
3180 <code>ExecCGI</code> key is not a common one. It must be
3181 configured manually in the windows registry and hence prevents
3182 accidental program calls on your system.</p>
3185 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3186 <div class="directive-section"><h2><a name="SeeRequestTail" id="SeeRequestTail">SeeRequestTail</a> <a name="seerequesttail" id="seerequesttail">Directive</a></h2>
3187 <table class="directive">
3188 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine if mod_status displays the first 63 characters
3189 of a request or the last 63, assuming the request itself is greater than
3191 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SeeRequestTail On|Off</code></td></tr>
3192 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SeeRequestTail Off</code></td></tr>
3193 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3194 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3195 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3196 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache httpd 2.2.7 and later.</td></tr>
3198 <p>mod_status with <code>ExtendedStatus On</code>
3199 displays the actual request being handled.
3200 For historical purposes, only 63 characters of the request
3201 are actually stored for display purposes. This directive
3202 controls whether the 1st 63 characters are stored (the previous
3203 behavior and the default) or if the last 63 characters are. This
3204 is only applicable, of course, if the length of the request is
3205 64 characters or greater.</p>
3207 <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:
3210 <table class="bordered">
3212 <th>Off (default)</th>
3213 <td>GET /disk1/storage/apache/htdocs/images/imagestore1/food/apples</td>
3217 <td>orage/apache/htdocs/images/imagestore1/food/apples.jpg HTTP/1.1</td>
3223 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3224 <div class="directive-section"><h2><a name="ServerAdmin" id="ServerAdmin">ServerAdmin</a> <a name="serveradmin" id="serveradmin">Directive</a></h2>
3225 <table class="directive">
3226 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Email address that the server includes in error
3227 messages sent to the client</td></tr>
3228 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAdmin <var>email-address</var>|<var>URL</var></code></td></tr>
3229 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3230 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3231 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3233 <p>The <code class="directive">ServerAdmin</code> sets the contact address
3234 that the server includes in any error messages it returns to the
3235 client. If the <code>httpd</code> doesn't recognize the supplied argument
3237 assumes, that it's an <var>email-address</var> and prepends it with
3238 <code>mailto:</code> in hyperlink targets. However, it's recommended to
3239 actually use an email address, since there are a lot of CGI scripts that
3240 make that assumption. If you want to use an URL, it should point to another
3241 server under your control. Otherwise users may not be able to contact you in
3244 <p>It may be worth setting up a dedicated address for this, e.g.</p>
3246 <div class="example"><p><code>
3247 ServerAdmin www-admin@foo.example.com
3249 <p>as users do not always mention that they are talking about the
3253 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3254 <div class="directive-section"><h2><a name="ServerAlias" id="ServerAlias">ServerAlias</a> <a name="serveralias" id="serveralias">Directive</a></h2>
3255 <table class="directive">
3256 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Alternate names for a host used when matching requests
3257 to name-virtual hosts</td></tr>
3258 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</code></td></tr>
3259 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
3260 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3261 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3263 <p>The <code class="directive">ServerAlias</code> directive sets the
3264 alternate names for a host, for use with <a href="../vhosts/name-based.html">name-based virtual hosts</a>. The
3265 <code class="directive">ServerAlias</code> may include wildcards, if appropriate.</p>
3267 <div class="example"><p><code>
3268 <VirtualHost *:80><br />
3269 ServerName server.domain.com<br />
3270 ServerAlias server server2.domain.com server2<br />
3271 ServerAlias *.example.com<br />
3272 UseCanonicalName Off<br />
3274 </VirtualHost>
3279 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3280 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
3283 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3284 <div class="directive-section"><h2><a name="ServerName" id="ServerName">ServerName</a> <a name="servername" id="servername">Directive</a></h2>
3285 <table class="directive">
3286 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hostname and port that the server uses to identify
3288 <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>
3289 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3290 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3291 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3293 <p>The <code class="directive">ServerName</code> directive sets the
3294 request scheme, hostname and
3295 port that the server uses to identify itself. This is used when
3296 creating redirection URLs. For example, if the name of the
3297 machine hosting the web server is <code>simple.example.com</code>,
3298 but the machine also has the DNS alias <code>www.example.com</code>
3299 and you wish the web server to be so identified, the following
3300 directive should be used:</p>
3302 <div class="example"><p><code>
3303 ServerName www.example.com:80
3306 <p>The <code class="directive">ServerName</code> directive
3307 may appear anywhere within the definition of a server. However,
3308 each appearance overrides the previous appearance (within that
3311 <p>If no <code class="directive">ServerName</code> is specified, then the
3312 server attempts to deduce the hostname by performing a reverse
3313 lookup on the IP address. If no port is specified in the
3314 <code class="directive">ServerName</code>, then the server will use the
3315 port from the incoming request. For optimal reliability and
3316 predictability, you should specify an explicit hostname and port
3317 using the <code class="directive">ServerName</code> directive.</p>
3319 <p>If you are using <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
3320 the <code class="directive">ServerName</code> inside a
3321 <code class="directive"><a href="#virtualhost"><VirtualHost></a></code>
3322 section specifies what hostname must appear in the request's
3323 <code>Host:</code> header to match this virtual host.</p>
3325 <p>Sometimes, the server runs behind a device that processes SSL,
3326 such as a reverse proxy, load balancer or SSL offload
3327 appliance. When this is the case, specify the
3328 <code>https://</code> scheme and the port number to which the
3329 clients connect in the <code class="directive">ServerName</code> directive
3330 to make sure that the server generates the correct
3331 self-referential URLs.
3334 <p>See the description of the
3335 <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> and
3336 <code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code> directives for
3337 settings which determine whether self-referential URLs (e.g., by the
3338 <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> module) will refer to the
3339 specified port, or to the port number given in the client's request.
3342 <div class="warning">
3343 <p>Failure to set <code class="directive">ServerName</code> to a name that
3344 your server can resolve to an IP address will result in a startup
3345 warning. <code>httpd</code> will then use whatever hostname it can
3346 determine, using the system's <code>hostname</code> command. This
3347 will almost never be the hostname you actually want.</p>
3348 <div class="example"><p><code>
3349 httpd: Could not reliably determine the server's fully qualified domain name, using rocinante.local for ServerName
3356 <li><a href="../dns-caveats.html">Issues Regarding DNS and
3357 Apache HTTP Server</a></li>
3358 <li><a href="../vhosts/">Apache HTTP Server virtual host
3359 documentation</a></li>
3360 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3361 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
3362 <li><code class="directive"><a href="#namevirtualhost">NameVirtualHost</a></code></li>
3363 <li><code class="directive"><a href="#serveralias">ServerAlias</a></code></li>
3366 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3367 <div class="directive-section"><h2><a name="ServerPath" id="ServerPath">ServerPath</a> <a name="serverpath" id="serverpath">Directive</a></h2>
3368 <table class="directive">
3369 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Legacy URL pathname for a name-based virtual host that
3370 is accessed by an incompatible browser</td></tr>
3371 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerPath <var>URL-path</var></code></td></tr>
3372 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
3373 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3374 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3376 <p>The <code class="directive">ServerPath</code> directive sets the legacy
3377 URL pathname for a host, for use with <a href="../vhosts/">name-based virtual hosts</a>.</p>
3381 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
3384 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3385 <div class="directive-section"><h2><a name="ServerRoot" id="ServerRoot">ServerRoot</a> <a name="serverroot" id="serverroot">Directive</a></h2>
3386 <table class="directive">
3387 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server installation</td></tr>
3388 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerRoot <var>directory-path</var></code></td></tr>
3389 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerRoot /usr/local/apache</code></td></tr>
3390 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3391 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3392 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3394 <p>The <code class="directive">ServerRoot</code> directive sets the
3395 directory in which the server lives. Typically it will contain the
3396 subdirectories <code>conf/</code> and <code>logs/</code>. Relative
3397 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
3398 relative to this directory.</p>
3400 <div class="example"><h3>Example</h3><p><code>
3401 ServerRoot /home/httpd
3407 <li><a href="../invoking.html">the <code>-d</code>
3408 option to <code>httpd</code></a></li>
3409 <li><a href="../misc/security_tips.html#serverroot">the
3410 security tips</a> for information on how to properly set
3411 permissions on the <code class="directive">ServerRoot</code></li>
3414 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3415 <div class="directive-section"><h2><a name="ServerSignature" id="ServerSignature">ServerSignature</a> <a name="serversignature" id="serversignature">Directive</a></h2>
3416 <table class="directive">
3417 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the footer on server-generated documents</td></tr>
3418 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerSignature On|Off|EMail</code></td></tr>
3419 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerSignature Off</code></td></tr>
3420 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3421 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
3422 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3423 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3425 <p>The <code class="directive">ServerSignature</code> directive allows the
3426 configuration of a trailing footer line under server-generated
3427 documents (error messages, <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> ftp directory
3428 listings, <code class="module"><a href="../mod/mod_info.html">mod_info</a></code> output, ...). The reason why you
3429 would want to enable such a footer line is that in a chain of proxies,
3430 the user often has no possibility to tell which of the chained servers
3431 actually produced a returned error message.</p>
3433 <p>The <code>Off</code>
3434 setting, which is the default, suppresses the footer line (and is
3435 therefore compatible with the behavior of Apache-1.2 and
3436 below). The <code>On</code> setting simply adds a line with the
3437 server version number and <code class="directive"><a href="#servername">ServerName</a></code> of the serving virtual host,
3438 and the <code>EMail</code> setting additionally creates a
3439 "mailto:" reference to the <code class="directive"><a href="#serveradmin">ServerAdmin</a></code> of the referenced
3442 <p>After version 2.0.44, the details of the server version number
3443 presented are controlled by the <code class="directive"><a href="#servertokens">ServerTokens</a></code> directive.</p>
3447 <li><code class="directive"><a href="#servertokens">ServerTokens</a></code></li>
3450 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3451 <div class="directive-section"><h2><a name="ServerTokens" id="ServerTokens">ServerTokens</a> <a name="servertokens" id="servertokens">Directive</a></h2>
3452 <table class="directive">
3453 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the <code>Server</code> HTTP response
3455 <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>
3456 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerTokens Full</code></td></tr>
3457 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3458 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3459 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3461 <p>This directive controls whether <code>Server</code> response
3462 header field which is sent back to clients includes a
3463 description of the generic OS-type of the server as well as
3464 information about compiled-in modules.</p>
3467 <dt><code>ServerTokens Full</code> (or not specified)</dt>
3469 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.1
3470 (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
3472 <dt><code>ServerTokens Prod[uctOnly]</code></dt>
3474 <dd>Server sends (<em>e.g.</em>): <code>Server:
3477 <dt><code>ServerTokens Major</code></dt>
3479 <dd>Server sends (<em>e.g.</em>): <code>Server:
3480 Apache/2</code></dd>
3482 <dt><code>ServerTokens Minor</code></dt>
3484 <dd>Server sends (<em>e.g.</em>): <code>Server:
3485 Apache/2.4</code></dd>
3487 <dt><code>ServerTokens Min[imal]</code></dt>
3489 <dd>Server sends (<em>e.g.</em>): <code>Server:
3490 Apache/2.4.1</code></dd>
3492 <dt><code>ServerTokens OS</code></dt>
3494 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.4.1
3499 <p>This setting applies to the entire server, and cannot be
3500 enabled or disabled on a virtualhost-by-virtualhost basis.</p>
3502 <p>After version 2.0.44, this directive also controls the
3503 information presented by the <code class="directive"><a href="#serversignature">ServerSignature</a></code> directive.</p>
3505 <div class="note">Setting <code class="directive">ServerTokens</code> to less than
3506 <code>minimal</code> is not recommended because it makes it more
3507 difficult to debug interoperational problems. Also note that
3508 disabling the Server: header does nothing at all to make your
3509 server more secure; the idea of "security through obscurity"
3510 is a myth and leads to a false sense of safety.</div>
3515 <li><code class="directive"><a href="#serversignature">ServerSignature</a></code></li>
3518 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3519 <div class="directive-section"><h2><a name="SetHandler" id="SetHandler">SetHandler</a> <a name="sethandler" id="sethandler">Directive</a></h2>
3520 <table class="directive">
3521 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be processed by a
3523 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetHandler <var>handler-name</var>|None</code></td></tr>
3524 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3525 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3526 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3527 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3528 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Moved into the core in Apache httpd 2.0</td></tr>
3530 <p>When placed into an <code>.htaccess</code> file or a
3531 <code class="directive"><a href="#directory"><Directory></a></code> or
3532 <code class="directive"><a href="#location"><Location></a></code>
3533 section, this directive forces all matching files to be parsed
3534 through the <a href="../handler.html">handler</a> given by
3535 <var>handler-name</var>. For example, if you had a directory you
3536 wanted to be parsed entirely as imagemap rule files, regardless
3537 of extension, you might put the following into an
3538 <code>.htaccess</code> file in that directory:</p>
3540 <div class="example"><p><code>
3541 SetHandler imap-file
3544 <p>Another example: if you wanted to have the server display a
3545 status report whenever a URL of
3546 <code>http://servername/status</code> was called, you might put
3547 the following into <code>httpd.conf</code>:</p>
3549 <div class="example"><p><code>
3550 <Location /status><br />
3551 <span class="indent">
3552 SetHandler server-status<br />
3557 <p>You can override an earlier defined <code class="directive">SetHandler</code>
3558 directive by using the value <code>None</code>.</p>
3559 <p><strong>Note:</strong> because SetHandler overrides default handlers,
3560 normal behaviour such as handling of URLs ending in a slash (/) as
3561 directories or index files is suppressed.</p>
3565 <li><code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code></li>
3568 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3569 <div class="directive-section"><h2><a name="SetInputFilter" id="SetInputFilter">SetInputFilter</a> <a name="setinputfilter" id="setinputfilter">Directive</a></h2>
3570 <table class="directive">
3571 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process client requests and POST
3573 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetInputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
3574 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3575 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3576 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3577 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3579 <p>The <code class="directive">SetInputFilter</code> directive sets the
3580 filter or filters which will process client requests and POST
3581 input when they are received by the server. This is in addition to
3582 any filters defined elsewhere, including the
3583 <code class="directive"><a href="../mod/mod_mime.html#addinputfilter">AddInputFilter</a></code>
3586 <p>If more than one filter is specified, they must be separated
3587 by semicolons in the order in which they should process the
3592 <li><a href="../filter.html">Filters</a> documentation</li>
3595 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3596 <div class="directive-section"><h2><a name="SetOutputFilter" id="SetOutputFilter">SetOutputFilter</a> <a name="setoutputfilter" id="setoutputfilter">Directive</a></h2>
3597 <table class="directive">
3598 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process responses from the
3600 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
3601 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
3602 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
3603 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3604 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3606 <p>The <code class="directive">SetOutputFilter</code> directive sets the filters
3607 which will process responses from the server before they are
3608 sent to the client. This is in addition to any filters defined
3609 elsewhere, including the
3610 <code class="directive"><a href="../mod/mod_mime.html#addoutputfilter">AddOutputFilter</a></code>
3613 <p>For example, the following configuration will process all files
3614 in the <code>/www/data/</code> directory for server-side
3617 <div class="example"><p><code>
3618 <Directory /www/data/><br />
3619 <span class="indent">
3620 SetOutputFilter INCLUDES<br />
3625 <p>If more than one filter is specified, they must be separated
3626 by semicolons in the order in which they should process the
3631 <li><a href="../filter.html">Filters</a> documentation</li>
3634 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3635 <div class="directive-section"><h2><a name="TimeOut" id="TimeOut">TimeOut</a> <a name="timeout" id="timeout">Directive</a></h2>
3636 <table class="directive">
3637 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for
3638 certain events before failing a request</td></tr>
3639 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TimeOut <var>seconds</var></code></td></tr>
3640 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TimeOut 300</code></td></tr>
3641 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
3642 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3643 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3645 <p>The <code class="directive">TimeOut</code> directive defines the length
3646 of time Apache httpd will wait for I/O in various circumstances:</p>
3649 <li>When reading data from the client, the length of time to
3650 wait for a TCP packet to arrive if the read buffer is
3653 <li>When writing data to the client, the length of time to wait
3654 for an acknowledgement of a packet if the send buffer is
3657 <li>In <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>, the length of time to wait for
3658 output from a CGI script.</li>
3660 <li>In <code class="module"><a href="../mod/mod_ext_filter.html">mod_ext_filter</a></code>, the length of time to
3661 wait for output from a filtering process.</li>
3663 <li>In <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>, the default timeout value if
3664 <code class="directive"><a href="../mod/mod_proxy.html#proxytimeout">ProxyTimeout</a></code> is not
3670 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3671 <div class="directive-section"><h2><a name="TraceEnable" id="TraceEnable">TraceEnable</a> <a name="traceenable" id="traceenable">Directive</a></h2>
3672 <table class="directive">
3673 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines the behaviour on <code>TRACE</code>
3675 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TraceEnable <var>[on|off|extended]</var></code></td></tr>
3676 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TraceEnable on</code></td></tr>
3677 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3678 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3679 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3680 <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>
3682 <p>This directive overrides the behavior of <code>TRACE</code> for both
3683 the core server and <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>. The default
3684 <code>TraceEnable on</code> permits <code>TRACE</code> requests per
3685 RFC 2616, which disallows any request body to accompany the request.
3686 <code>TraceEnable off</code> causes the core server and
3687 <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> to return a <code>405</code> (Method not
3688 allowed) error to the client.</p>
3690 <p>Finally, for testing and diagnostic purposes only, request
3691 bodies may be allowed using the non-compliant <code>TraceEnable
3692 extended</code> directive. The core (as an origin server) will
3693 restrict the request body to 64k (plus 8k for chunk headers if
3694 <code>Transfer-Encoding: chunked</code> is used). The core will
3695 reflect the full headers and all chunk headers with the response
3696 body. As a proxy server, the request body is not restricted to 64k.</p>
3699 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3700 <div class="directive-section"><h2><a name="UnDefine" id="UnDefine">UnDefine</a> <a name="undefine" id="undefine">Directive</a></h2>
3701 <table class="directive">
3702 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Undefine the existence of a variable</td></tr>
3703 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UnDefine <var>parameter-name</var></code></td></tr>
3704 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3705 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3706 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3708 <p>Undoes the effect of a <code class="directive"><a href="#define">Define</a></code> or
3709 of passing a <code>-D</code> argument to <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</p>
3710 <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
3711 <code>-D</code> arguments in any startup scripts.</p>
3714 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3715 <div class="directive-section"><h2><a name="UseCanonicalName" id="UseCanonicalName">UseCanonicalName</a> <a name="usecanonicalname" id="usecanonicalname">Directive</a></h2>
3716 <table class="directive">
3717 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own name and
3719 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalName On|Off|DNS</code></td></tr>
3720 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalName Off</code></td></tr>
3721 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3722 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3723 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3725 <p>In many situations Apache httpd must construct a <em>self-referential</em>
3726 URL -- that is, a URL that refers back to the same server. With
3727 <code>UseCanonicalName On</code> Apache httpd will use the hostname and port
3728 specified in the <code class="directive"><a href="#servername">ServerName</a></code>
3729 directive to construct the canonical name for the server. This name
3730 is used in all self-referential URLs, and for the values of
3731 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>
3733 <p>With <code>UseCanonicalName Off</code> Apache httpd will form
3734 self-referential URLs using the hostname and port supplied by
3735 the client if any are supplied (otherwise it will use the
3736 canonical name, as defined above). These values are the same
3737 that are used to implement <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
3738 and are available with the same clients. The CGI variables
3739 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
3740 constructed from the client supplied values as well.</p>
3742 <p>An example where this may be useful is on an intranet server
3743 where you have users connecting to the machine using short
3744 names such as <code>www</code>. You'll notice that if the users
3745 type a shortname, and a URL which is a directory, such as
3746 <code>http://www/splat</code>, <em>without the trailing
3747 slash</em> then Apache httpd will redirect them to
3748 <code>http://www.domain.com/splat/</code>. If you have
3749 authentication enabled, this will cause the user to have to
3750 authenticate twice (once for <code>www</code> and once again
3751 for <code>www.domain.com</code> -- see <a href="http://httpd.apache.org/docs/misc/FAQ.html#prompted-twice">the
3752 FAQ on this subject for more information</a>). But if
3753 <code class="directive">UseCanonicalName</code> is set <code>Off</code>, then
3754 Apache httpd will redirect to <code>http://www/splat/</code>.</p>
3756 <p>There is a third option, <code>UseCanonicalName DNS</code>,
3757 which is intended for use with mass IP-based virtual hosting to
3758 support ancient clients that do not provide a
3759 <code>Host:</code> header. With this option Apache httpd does a
3760 reverse DNS lookup on the server IP address that the client
3761 connected to in order to work out self-referential URLs.</p>
3763 <div class="warning"><h3>Warning</h3>
3764 <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>
3765 they may be broken by this option. The client is essentially free
3766 to give whatever value they want as a hostname. But if the CGI is
3767 only using <code>SERVER_NAME</code> to construct self-referential URLs
3768 then it should be just fine.</p>
3773 <li><code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
3774 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
3775 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
3778 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3779 <div class="directive-section"><h2><a name="UseCanonicalPhysicalPort" id="UseCanonicalPhysicalPort">UseCanonicalPhysicalPort</a> <a name="usecanonicalphysicalport" id="usecanonicalphysicalport">Directive</a></h2>
3780 <table class="directive">
3781 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own name and
3783 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalPhysicalPort On|Off</code></td></tr>
3784 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalPhysicalPort Off</code></td></tr>
3785 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
3786 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3787 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3789 <p>In many situations Apache httpd must construct a <em>self-referential</em>
3790 URL -- that is, a URL that refers back to the same server. With
3791 <code>UseCanonicalPhysicalPort On</code> Apache httpd will, when
3792 constructing the canonical port for the server to honor
3793 the <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> directive,
3794 provide the actual physical port number being used by this request
3795 as a potential port. With <code>UseCanonicalPhysicalPort Off</code>
3796 Apache httpd will not ever use the actual physical port number, instead
3797 relying on all configured information to construct a valid port number.</p>
3799 <div class="note"><h3>Note</h3>
3800 <p>The ordering of when the physical port is used is as follows:<br /><br />
3801 <code>UseCanonicalName On</code></p>
3803 <li>Port provided in <code>Servername</code></li>
3804 <li>Physical port</li>
3805 <li>Default port</li>
3807 <code>UseCanonicalName Off | DNS</code>
3809 <li>Parsed port from <code>Host:</code> header</li>
3810 <li>Physical port</li>
3811 <li>Port provided in <code>Servername</code></li>
3812 <li>Default port</li>
3815 <p>With <code>UseCanonicalPhysicalPort Off</code>, the
3816 physical ports are removed from the ordering.</p>
3822 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
3823 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
3824 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
3827 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
3828 <div class="directive-section"><h2><a name="VirtualHost" id="VirtualHost"><VirtualHost></a> <a name="virtualhost" id="virtualhost">Directive</a></h2>
3829 <table class="directive">
3830 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only to a specific
3831 hostname or IP address</td></tr>
3832 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><VirtualHost
3833 <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
3834 ...> ... </VirtualHost></code></td></tr>
3835 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
3836 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
3837 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
3839 <p><code class="directive"><VirtualHost></code> and
3840 <code></VirtualHost></code> are used to enclose a group of
3841 directives that will apply only to a particular virtual host. Any
3842 directive that is allowed in a virtual host context may be
3843 used. When the server receives a request for a document on a
3844 particular virtual host, it uses the configuration directives
3845 enclosed in the <code class="directive"><VirtualHost></code>
3846 section. <var>Addr</var> can be:</p>
3849 <li>The IP address of the virtual host;</li>
3851 <li>A fully qualified domain name for the IP address of the
3852 virtual host (not recommended);</li>
3854 <li>The character <code>*</code>, which is used only in combination with
3855 <code>NameVirtualHost *</code> to match all IP addresses; or</li>
3857 <li>The string <code>_default_</code>, which is used only
3858 with IP virtual hosting to catch unmatched IP addresses.</li>
3861 <div class="example"><h3>Example</h3><p><code>
3862 <VirtualHost 10.1.2.3><br />
3863 <span class="indent">
3864 ServerAdmin webmaster@host.example.com<br />
3865 DocumentRoot /www/docs/host.example.com<br />
3866 ServerName host.example.com<br />
3867 ErrorLog logs/host.example.com-error_log<br />
3868 TransferLog logs/host.example.com-access_log<br />
3870 </VirtualHost>
3874 <p>IPv6 addresses must be specified in square brackets because
3875 the optional port number could not be determined otherwise. An
3876 IPv6 example is shown below:</p>
3878 <div class="example"><p><code>
3879 <VirtualHost [2001:db8::a00:20ff:fea7:ccea]><br />
3880 <span class="indent">
3881 ServerAdmin webmaster@host.example.com<br />
3882 DocumentRoot /www/docs/host.example.com<br />
3883 ServerName host.example.com<br />
3884 ErrorLog logs/host.example.com-error_log<br />
3885 TransferLog logs/host.example.com-access_log<br />
3887 </VirtualHost>
3890 <p>Each Virtual Host must correspond to a different IP address,
3891 different port number or a different host name for the server,
3892 in the former case the server machine must be configured to
3893 accept IP packets for multiple addresses. (If the machine does
3894 not have multiple network interfaces, then this can be
3895 accomplished with the <code>ifconfig alias</code> command -- if
3896 your OS supports it).</p>
3898 <div class="note"><h3>Note</h3>
3899 <p>The use of <code class="directive"><VirtualHost></code> does
3900 <strong>not</strong> affect what addresses Apache httpd listens on. You
3901 may need to ensure that Apache httpd is listening on the correct addresses
3902 using <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>.</p>
3905 <p>When using IP-based virtual hosting, the special name
3906 <code>_default_</code> can be specified in
3907 which case this virtual host will match any IP address that is
3908 not explicitly listed in another virtual host. In the absence
3909 of any <code>_default_</code> virtual host the "main" server config,
3910 consisting of all those definitions outside any VirtualHost
3911 section, is used when no IP-match occurs.</p>
3913 <p>You can specify a <code>:port</code> to change the port that is
3914 matched. If unspecified then it defaults to the same port as the
3915 most recent <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>
3916 statement of the main server. You may also specify <code>:*</code>
3917 to match all ports on that address. (This is recommended when used
3918 with <code>_default_</code>.)</p>
3920 <p>A <code class="directive"><a href="#servername">ServerName</a></code> should be
3921 specified inside each <code class="directive"><VirtualHost></code> block. If it is absent, the
3922 <code class="directive"><a href="#servername">ServerName</a></code> from the "main"
3923 server configuration will be inherited.</p>
3925 <p>If no matching virtual host is found, then the first listed
3926 virtual host that matches the IP address will be used. As a
3927 consequence, the first listed virtual host is the default virtual
3930 <div class="warning"><h3>Security</h3>
3931 <p>See the <a href="../misc/security_tips.html">security tips</a>
3932 document for details on why your security could be compromised if the
3933 directory where log files are stored is writable by anyone other
3934 than the user that starts the server.</p>
3939 <li><a href="../vhosts/">Apache HTTP Server Virtual Host documentation</a></li>
3940 <li><a href="../dns-caveats.html">Issues Regarding DNS and
3941 Apache HTTP Server</a></li>
3942 <li><a href="../bind.html">Setting
3943 which addresses and ports Apache HTTP Server uses</a></li>
3944 <li><a href="../sections.html">How <Directory>, <Location>
3945 and <Files> sections work</a> for an explanation of how these
3946 different sections are combined when a request is received</li>
3950 <div class="bottomlang">
3951 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
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3956 </div><div id="footer">
3957 <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>
3958 <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>