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7 Licensed to the Apache Software Foundation (ASF) under one or more
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9 this work for additional information regarding copyright ownership.
10 The ASF licenses this file to You under the Apache License, Version 2.0
11 (the "License"); you may not use this file except in compliance with
12 the License. You may obtain a copy of the License at
14 http://www.apache.org/licenses/LICENSE-2.0
16 Unless required by applicable law or agreed to in writing, software
17 distributed under the License is distributed on an "AS IS" BASIS,
18 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19 See the License for the specific language governing permissions and
20 limitations under the License.
23 <modulesynopsis metafile="core.xml.meta">
26 <description>Core Apache HTTP Server features that are always
27 available</description>
31 <name>AcceptFilter</name>
32 <description>Configures optimizations for a Protocol's Listener Sockets</description>
33 <syntax>AcceptFilter <var>protocol</var> <var>accept_filter</var></syntax>
34 <contextlist><context>server config</context></contextlist>
35 <compatibility>Available in Apache 2.1.5 and later.
36 On Windows from Apache 2.3.3 and later.</compatibility>
39 <p>This directive enables operating system specific optimizations for a
40 listening socket by the Protocol type. The basic premise is for the
41 kernel to not send a socket to the server process until either data
42 is received or an entire HTTP Request is buffered. Only
43 <a href="http://www.freebsd.org/cgi/man.cgi?query=accept_filter&sektion=9">
44 FreeBSD's Accept Filters</a>, Linux's more primitive
45 <code>TCP_DEFER_ACCEPT</code>, and Windows' optimized AcceptEx()
46 are currently supported.</p>
48 <p>Using <code>none</code> for an argument will disable any accept filters
49 for that protocol. This is useful for protocols that require a server
50 send data first, such as <code>ftp:</code> or <code>nntp</code>:</p>
51 <example>AcceptFilter nntp none</example>
53 <p>The default values on FreeBSD are:</p>
55 AcceptFilter http httpready <br/>
56 AcceptFilter https dataready
59 <p>The <code>httpready</code> accept filter buffers entire HTTP requests at
60 the kernel level. Once an entire request is received, the kernel then
61 sends it to the server. See the
62 <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_http&sektion=9">
63 accf_http(9)</a> man page for more details. Since HTTPS requests are
64 encrypted only the <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_data&sektion=9">
65 accf_data(9)</a> filter is used.</p>
67 <p>The default values on Linux are:</p>
69 AcceptFilter http data <br/>
70 AcceptFilter https data
73 <p>Linux's <code>TCP_DEFER_ACCEPT</code> does not support buffering http
74 requests. Any value besides <code>none</code> will enable
75 <code>TCP_DEFER_ACCEPT</code> on that listener. For more details
77 <a href="http://homepages.cwi.nl/~aeb/linux/man2html/man7/tcp.7.html">
78 tcp(7)</a> man page.</p>
80 <p>The default values on Windows are:</p>
82 AcceptFilter http data <br/>
83 AcceptFilter https data
86 <p>Window's mpm_winnt interprets the AcceptFilter to toggle the AcceptEx()
87 API, and does not support http protocol buffering. There are two values
88 which utilize the Windows AcceptEx() API and will recycle network
89 sockets between connections. <code>data</code> waits until data has
90 been transmitted as documented above, and the initial data buffer and
91 network endpoint addresses are all retrieved from the single AcceptEx()
92 invocation. <code>connect</code> will use the AcceptEx() API, also
93 retrieve the network endpoint addresses, but like <code>none</code>
94 the <code>connect</code> option does not wait for the initial data
97 <p>On Windows, <code>none</code> uses accept() rather than than AcceptEx()
98 and will not recycle sockets between connections. This is useful for
99 network adapters with broken driver support, as well as some virtual
100 network providers such as vpn drivers, or spam, virus or spyware
107 <name>AcceptPathInfo</name>
108 <description>Resources accept trailing pathname information</description>
109 <syntax>AcceptPathInfo On|Off|Default</syntax>
110 <default>AcceptPathInfo Default</default>
111 <contextlist><context>server config</context>
112 <context>virtual host</context><context>directory</context>
113 <context>.htaccess</context></contextlist>
114 <override>FileInfo</override>
115 <compatibility>Available in Apache 2.0.30 and later</compatibility>
119 <p>This directive controls whether requests that contain trailing
120 pathname information that follows an actual filename (or
121 non-existent file in an existing directory) will be accepted or
122 rejected. The trailing pathname information can be made
123 available to scripts in the <code>PATH_INFO</code> environment
126 <p>For example, assume the location <code>/test/</code> points to
127 a directory that contains only the single file
128 <code>here.html</code>. Then requests for
129 <code>/test/here.html/more</code> and
130 <code>/test/nothere.html/more</code> both collect
131 <code>/more</code> as <code>PATH_INFO</code>.</p>
133 <p>The three possible arguments for the
134 <directive>AcceptPathInfo</directive> directive are:</p>
136 <dt><code>Off</code></dt><dd>A request will only be accepted if it
137 maps to a literal path that exists. Therefore a request with
138 trailing pathname information after the true filename such as
139 <code>/test/here.html/more</code> in the above example will return
140 a 404 NOT FOUND error.</dd>
142 <dt><code>On</code></dt><dd>A request will be accepted if a
143 leading path component maps to a file that exists. The above
144 example <code>/test/here.html/more</code> will be accepted if
145 <code>/test/here.html</code> maps to a valid file.</dd>
147 <dt><code>Default</code></dt><dd>The treatment of requests with
148 trailing pathname information is determined by the <a
149 href="../handler.html">handler</a> responsible for the request.
150 The core handler for normal files defaults to rejecting
151 <code>PATH_INFO</code> requests. Handlers that serve scripts, such as <a
152 href="mod_cgi.html">cgi-script</a> and <a
153 href="mod_isapi.html">isapi-handler</a>, generally accept
154 <code>PATH_INFO</code> by default.</dd>
157 <p>The primary purpose of the <code>AcceptPathInfo</code>
158 directive is to allow you to override the handler's choice of
159 accepting or rejecting <code>PATH_INFO</code>. This override is required,
160 for example, when you use a <a href="../filter.html">filter</a>, such
161 as <a href="mod_include.html">INCLUDES</a>, to generate content
162 based on <code>PATH_INFO</code>. The core handler would usually reject
163 the request, so you can use the following configuration to enable
167 <Files "mypaths.shtml"><br />
169 Options +Includes<br />
170 SetOutputFilter INCLUDES<br />
171 AcceptPathInfo On<br />
180 <name>AccessFileName</name>
181 <description>Name of the distributed configuration file</description>
182 <syntax>AccessFileName <var>filename</var> [<var>filename</var>] ...</syntax>
183 <default>AccessFileName .htaccess</default>
184 <contextlist><context>server config</context><context>virtual host</context>
188 <p>While processing a request the server looks for
189 the first existing configuration file from this list of names in
190 every directory of the path to the document, if distributed
191 configuration files are <a href="#allowoverride">enabled for that
192 directory</a>. For example:</p>
198 <p>before returning the document
199 <code>/usr/local/web/index.html</code>, the server will read
200 <code>/.acl</code>, <code>/usr/.acl</code>,
201 <code>/usr/local/.acl</code> and <code>/usr/local/web/.acl</code>
202 for directives, unless they have been disabled with</p>
205 <Directory /><br />
207 AllowOverride None<br />
212 <seealso><directive module="core">AllowOverride</directive></seealso>
213 <seealso><a href="../configuring.html">Configuration Files</a></seealso>
214 <seealso><a href="../howto/htaccess.html">.htaccess Files</a></seealso>
218 <name>AddDefaultCharset</name>
219 <description>Default charset parameter to be added when a response
220 content-type is <code>text/plain</code> or <code>text/html</code></description>
221 <syntax>AddDefaultCharset On|Off|<var>charset</var></syntax>
222 <default>AddDefaultCharset Off</default>
223 <contextlist><context>server config</context>
224 <context>virtual host</context><context>directory</context>
225 <context>.htaccess</context></contextlist>
226 <override>FileInfo</override>
229 <p>This directive specifies a default value for the media type
230 charset parameter (the name of a character encoding) to be added
231 to a response if and only if the response's content-type is either
232 <code>text/plain</code> or <code>text/html</code>. This should override
233 any charset specified in the body of the response via a <code>META</code>
234 element, though the exact behavior is often dependent on the user's client
235 configuration. A setting of <code>AddDefaultCharset Off</code>
236 disables this functionality. <code>AddDefaultCharset On</code> enables
237 a default charset of <code>iso-8859-1</code>. Any other value is assumed
238 to be the <var>charset</var> to be used, which should be one of the
239 <a href="http://www.iana.org/assignments/character-sets">IANA registered
240 charset values</a> for use in Internet media types (MIME types).
244 AddDefaultCharset utf-8
247 <p><directive>AddDefaultCharset</directive> should only be used when all
248 of the text resources to which it applies are known to be in that
249 character encoding and it is too inconvenient to label their charset
250 individually. One such example is to add the charset parameter
251 to resources containing generated content, such as legacy CGI
252 scripts, that might be vulnerable to cross-site scripting attacks
253 due to user-provided data being included in the output. Note, however,
254 that a better solution is to just fix (or delete) those scripts, since
255 setting a default charset does not protect users that have enabled
256 the "auto-detect character encoding" feature on their browser.</p>
258 <seealso><directive module="mod_mime">AddCharset</directive></seealso>
262 <name>AddOutputFilterByType</name>
263 <description>assigns an output filter to a particular media-type</description>
264 <syntax>AddOutputFilterByType <var>filter</var>[;<var>filter</var>...]
265 <var>media-type</var> [<var>media-type</var>] ...</syntax>
266 <contextlist><context>server config</context>
267 <context>virtual host</context><context>directory</context>
268 <context>.htaccess</context></contextlist>
269 <override>FileInfo</override>
270 <compatibility>Available in Apache 2.0.33 and later; deprecated in Apache 2.1 and later</compatibility>
273 <p>This directive activates a particular output <a
274 href="../filter.html">filter</a> for a request depending on the
275 response <glossary>media-type</glossary>. Because of certain
276 problems discussed below, this directive is deprecated. The same
277 functionality is available using <module>mod_filter</module>.</p>
279 <p>The following example uses the <code>DEFLATE</code> filter, which
280 is provided by <module>mod_deflate</module>. It will compress all
281 output (either static or dynamic) which is labeled as
282 <code>text/html</code> or <code>text/plain</code> before it is sent
286 AddOutputFilterByType DEFLATE text/html text/plain
289 <p>If you want the content to be processed by more than one filter, their
290 names have to be separated by semicolons. It's also possible to use one
291 <directive>AddOutputFilterByType</directive> directive for each of
294 <p>The configuration below causes all script output labeled as
295 <code>text/html</code> to be processed at first by the
296 <code>INCLUDES</code> filter and then by the <code>DEFLATE</code>
300 <Location /cgi-bin/><br />
302 Options Includes<br />
303 AddOutputFilterByType INCLUDES;DEFLATE text/html<br />
308 <note type="warning"><title>Note</title>
309 <p>Enabling filters with <directive>AddOutputFilterByType</directive>
310 may fail partially or completely in some cases. For example, no
311 filters are applied if the <glossary>media-type</glossary> could not
312 be determined. If you want to make sure that the filters will be
313 applied, assign the content type to a resource explicitly; for
314 example, with <directive module="mod_mime">AddType</directive> or
315 <directive module="core">ForceType</directive>. Setting the
316 content type within a (non-nph) CGI script is also safe.</p>
321 <seealso><directive module="mod_mime">AddOutputFilter</directive></seealso>
322 <seealso><directive module="core">SetOutputFilter</directive></seealso>
323 <seealso><a href="../filter.html">filters</a></seealso>
327 <name>AllowEncodedSlashes</name>
328 <description>Determines whether encoded path separators in URLs are allowed to
329 be passed through</description>
330 <syntax>AllowEncodedSlashes On|Off</syntax>
331 <default>AllowEncodedSlashes Off</default>
332 <contextlist><context>server config</context><context>virtual host</context>
334 <compatibility>Available in Apache 2.0.46 and later</compatibility>
337 <p>The <directive>AllowEncodedSlashes</directive> directive allows URLs
338 which contain encoded path separators (<code>%2F</code> for <code>/</code>
339 and additionally <code>%5C</code> for <code>\</code> on according systems)
340 to be used. Normally such URLs are refused with a 404 (Not found) error.</p>
342 <p>Turning <directive>AllowEncodedSlashes</directive> <code>On</code> is
343 mostly useful when used in conjunction with <code>PATH_INFO</code>.</p>
345 <note><title>Note</title>
346 <p>Allowing encoded slashes does <em>not</em> imply <em>decoding</em>.
347 Occurrences of <code>%2F</code> or <code>%5C</code> (<em>only</em> on
348 according systems) will be left as such in the otherwise decoded URL
352 <seealso><directive module="core">AcceptPathInfo</directive></seealso>
356 <name>AllowOverride</name>
357 <description>Types of directives that are allowed in
358 <code>.htaccess</code> files</description>
359 <syntax>AllowOverride All|None|<var>directive-type</var>
360 [<var>directive-type</var>] ...</syntax>
361 <default>AllowOverride All</default>
362 <contextlist><context>directory</context></contextlist>
365 <p>When the server finds an <code>.htaccess</code> file (as
366 specified by <directive module="core">AccessFileName</directive>)
367 it needs to know which directives declared in that file can override
368 earlier configuration directives.</p>
370 <note><title>Only available in <Directory> sections</title>
371 <directive>AllowOverride</directive> is valid only in
372 <directive type="section" module="core">Directory</directive>
373 sections specified without regular expressions, not in <directive
374 type="section" module="core">Location</directive>, <directive
375 module="core" type="section">DirectoryMatch</directive> or
376 <directive type="section" module="core">Files</directive> sections.
379 <p>When this directive is set to <code>None</code>, then
380 <a href="#accessfilename">.htaccess</a> files are completely ignored.
381 In this case, the server will not even attempt to read
382 <code>.htaccess</code> files in the filesystem.</p>
384 <p>When this directive is set to <code>All</code>, then any
385 directive which has the .htaccess <a
386 href="directive-dict.html#Context">Context</a> is allowed in
387 <code>.htaccess</code> files.</p>
389 <p>The <var>directive-type</var> can be one of the following
390 groupings of directives.</p>
397 Allow use of the authorization directives (<directive
398 module="mod_authn_dbm">AuthDBMGroupFile</directive>,
399 <directive module="mod_authn_dbm">AuthDBMUserFile</directive>,
400 <directive module="mod_authz_groupfile">AuthGroupFile</directive>,
401 <directive module="mod_authn_core">AuthName</directive>,
402 <directive module="mod_authn_core">AuthType</directive>, <directive
403 module="mod_authn_file">AuthUserFile</directive>, <directive
404 module="mod_authz_core">Require</directive>, <em>etc.</em>).</dd>
409 Allow use of the directives controlling document types
410 (<directive module="core">ErrorDocument</directive>,
411 <directive module="core">ForceType</directive>,
412 <directive module="mod_negotiation">LanguagePriority</directive>,
413 <directive module="core">SetHandler</directive>,
414 <directive module="core">SetInputFilter</directive>,
415 <directive module="core">SetOutputFilter</directive>, and
416 <module>mod_mime</module> Add* and Remove* directives),
417 document meta data (<directive
418 module="mod_headers">Header</directive>, <directive
419 module="mod_headers">RequestHeader</directive>, <directive
420 module="mod_setenvif">SetEnvIf</directive>, <directive
421 module="mod_setenvif">SetEnvIfNoCase</directive>, <directive
422 module="mod_setenvif">BrowserMatch</directive>, <directive
423 module="mod_usertrack">CookieExpires</directive>, <directive
424 module="mod_usertrack">CookieDomain</directive>, <directive
425 module="mod_usertrack">CookieStyle</directive>, <directive
426 module="mod_usertrack">CookieTracking</directive>, <directive
427 module="mod_usertrack">CookieName</directive>),
428 <module>mod_rewrite</module> directives <directive
429 module="mod_rewrite">RewriteEngine</directive>, <directive
430 module="mod_rewrite">RewriteOptions</directive>, <directive
431 module="mod_rewrite">RewriteBase</directive>, <directive
432 module="mod_rewrite">RewriteCond</directive>, <directive
433 module="mod_rewrite">RewriteRule</directive>) and
434 <directive module="mod_actions">Action</directive> from
435 <module>mod_actions</module>.
441 Allow use of the directives controlling directory indexing
443 module="mod_autoindex">AddDescription</directive>,
444 <directive module="mod_autoindex">AddIcon</directive>, <directive
445 module="mod_autoindex">AddIconByEncoding</directive>,
446 <directive module="mod_autoindex">AddIconByType</directive>,
447 <directive module="mod_autoindex">DefaultIcon</directive>, <directive
448 module="mod_dir">DirectoryIndex</directive>, <directive
449 module="mod_autoindex">FancyIndexing</directive>, <directive
450 module="mod_autoindex">HeaderName</directive>, <directive
451 module="mod_autoindex">IndexIgnore</directive>, <directive
452 module="mod_autoindex">IndexOptions</directive>, <directive
453 module="mod_autoindex">ReadmeName</directive>,
459 Allow use of the directives controlling host access (<directive
460 module="mod_authz_host">Allow</directive>, <directive
461 module="mod_authz_host">Deny</directive> and <directive
462 module="mod_authz_host">Order</directive>).</dd>
464 <dt>Options[=<var>Option</var>,...]</dt>
467 Allow use of the directives controlling specific directory
468 features (<directive module="core">Options</directive> and
469 <directive module="mod_include">XBitHack</directive>).
470 An equal sign may be given followed by a comma (but no spaces)
471 separated lists of options that may be set using the <directive
472 module="core">Options</directive> command.</dd>
478 AllowOverride AuthConfig Indexes
481 <p>In the example above all directives that are neither in the group
482 <code>AuthConfig</code> nor <code>Indexes</code> cause an internal
485 <note><p>For security and performance reasons, do not set
486 <code>AllowOverride</code> to anything other than <code>None</code>
487 in your <code><Directory /></code> block. Instead, find (or
488 create) the <code><Directory></code> block that refers to the
489 directory where you're actually planning to place a
490 <code>.htaccess</code> file.</p>
494 <seealso><directive module="core">AccessFileName</directive></seealso>
495 <seealso><a href="../configuring.html">Configuration Files</a></seealso>
496 <seealso><a href="../howto/htaccess.html">.htaccess Files</a></seealso>
500 <name>CGIMapExtension</name>
501 <description>Technique for locating the interpreter for CGI
502 scripts</description>
503 <syntax>CGIMapExtension <var>cgi-path</var> <var>.extension</var></syntax>
504 <contextlist><context>directory</context><context>.htaccess</context>
506 <override>FileInfo</override>
507 <compatibility>NetWare only</compatibility>
510 <p>This directive is used to control how Apache finds the
511 interpreter used to run CGI scripts. For example, setting
512 <code>CGIMapExtension sys:\foo.nlm .foo</code> will
513 cause all CGI script files with a <code>.foo</code> extension to
514 be passed to the FOO interpreter.</p>
519 <name>ContentDigest</name>
520 <description>Enables the generation of <code>Content-MD5</code> HTTP Response
521 headers</description>
522 <syntax>ContentDigest On|Off</syntax>
523 <default>ContentDigest Off</default>
524 <contextlist><context>server config</context><context>virtual host</context>
525 <context>directory</context><context>.htaccess</context>
527 <override>Options</override>
528 <status>Experimental</status>
531 <p>This directive enables the generation of
532 <code>Content-MD5</code> headers as defined in RFC1864
533 respectively RFC2616.</p>
535 <p>MD5 is an algorithm for computing a "message digest"
536 (sometimes called "fingerprint") of arbitrary-length data, with
537 a high degree of confidence that any alterations in the data
538 will be reflected in alterations in the message digest.</p>
540 <p>The <code>Content-MD5</code> header provides an end-to-end
541 message integrity check (MIC) of the entity-body. A proxy or
542 client may check this header for detecting accidental
543 modification of the entity-body in transit. Example header:</p>
546 Content-MD5: AuLb7Dp1rqtRtxz2m9kRpA==
549 <p>Note that this can cause performance problems on your server
550 since the message digest is computed on every request (the
551 values are not cached).</p>
553 <p><code>Content-MD5</code> is only sent for documents served
554 by the <module>core</module>, and not by any module. For example,
555 SSI documents, output from CGI scripts, and byte range responses
556 do not have this header.</p>
561 <name>DefaultType</name>
562 <description>This directive has no effect other than to emit warnings
563 if the value is not <code>none</code>. In prior versions, DefaultType
564 would specify a default media type to assign to response content for
565 which no other media type configuration could be found.
567 <syntax>DefaultType <var>media-type|none</var></syntax>
568 <default>DefaultType none</default>
569 <contextlist><context>server config</context><context>virtual host</context>
570 <context>directory</context><context>.htaccess</context>
572 <override>FileInfo</override>
573 <compatibility>The argument <code>none</code> is available in Apache 2.2.7 and later. All other choices are DISABLED for 2.3.x and later.</compatibility>
576 <p>This directive has been disabled. For backwards compatibility
577 of configuration files, it may be specified with the value
578 <code>none</code>, meaning no default media type. For example:</p>
584 <p><code>DefaultType None</code> is only available in
585 httpd-2.2.7 and later.</p>
587 <p>Use the mime.types configuration file and the
588 <directive module="mod_mime">AddType</directive> to configure media
589 type assignments via file extensions, or the
590 <directive module="core">ForceType</directive> directive to configure
591 the media type for specific resources. Otherwise, the server will
592 send the response without a Content-Type header field and the
593 recipient may attempt to guess the media type.</p>
599 <description>Define the existence of a variable</description>
600 <syntax>Define <var>parameter-name</var></syntax>
601 <contextlist><context>server config</context></contextlist>
604 <p>Equivalent to passing the <code>-D</code> argument to <program
605 >httpd</program>.</p>
606 <p>This directive can be used to toggle the use of <directive module="core"
607 type="section">IfDefine</directive> sections without needing to alter
608 <code>-D</code> arguments in any startup scripts.</p>
612 <directivesynopsis type="section">
613 <name>Directory</name>
614 <description>Enclose a group of directives that apply only to the
615 named file-system directory and sub-directories</description>
616 <syntax><Directory <var>directory-path</var>>
617 ... </Directory></syntax>
618 <contextlist><context>server config</context><context>virtual host</context>
622 <p><directive type="section">Directory</directive> and
623 <code></Directory></code> are used to enclose a group of
624 directives that will apply only to the named directory and
625 sub-directories of that directory. Any directive that is allowed
626 in a directory context may be used. <var>Directory-path</var> is
627 either the full path to a directory, or a wild-card string using
628 Unix shell-style matching. In a wild-card string, <code>?</code> matches
629 any single character, and <code>*</code> matches any sequences of
630 characters. You may also use <code>[]</code> character ranges. None
631 of the wildcards match a `/' character, so <code><Directory
632 /*/public_html></code> will not match
633 <code>/home/user/public_html</code>, but <code><Directory
634 /home/*/public_html></code> will match. Example:</p>
637 <Directory /usr/local/httpd/htdocs><br />
639 Options Indexes FollowSymLinks<br />
645 <p>Be careful with the <var>directory-path</var> arguments:
646 They have to literally match the filesystem path which Apache uses
647 to access the files. Directives applied to a particular
648 <code><Directory></code> will not apply to files accessed from
649 that same directory via a different path, such as via different symbolic
653 <p><glossary ref="regex">Regular
654 expressions</glossary> can also be used, with the addition of the
655 <code>~</code> character. For example:</p>
658 <Directory ~ "^/www/.*/[0-9]{3}">
661 <p>would match directories in <code>/www/</code> that consisted of
664 <p>If multiple (non-regular expression) <directive
665 type="section">Directory</directive> sections
666 match the directory (or one of its parents) containing a document,
667 then the directives are applied in the order of shortest match
668 first, interspersed with the directives from the <a
669 href="#accessfilename">.htaccess</a> files. For example,
673 <Directory /><br />
675 AllowOverride None<br />
677 </Directory><br />
679 <Directory /home/><br />
681 AllowOverride FileInfo<br />
686 <p>for access to the document <code>/home/web/dir/doc.html</code>
690 <li>Apply directive <code>AllowOverride None</code>
691 (disabling <code>.htaccess</code> files).</li>
693 <li>Apply directive <code>AllowOverride FileInfo</code> (for
694 directory <code>/home</code>).</li>
696 <li>Apply any <code>FileInfo</code> directives in
697 <code>/home/.htaccess</code>, <code>/home/web/.htaccess</code> and
698 <code>/home/web/dir/.htaccess</code> in that order.</li>
701 <p>Regular expressions are not considered until after all of the
702 normal sections have been applied. Then all of the regular
703 expressions are tested in the order they appeared in the
704 configuration file. For example, with</p>
707 <Directory ~ abc$><br />
709 # ... directives here ...<br />
714 <p>the regular expression section won't be considered until after
715 all normal <directive type="section">Directory</directive>s and
716 <code>.htaccess</code> files have been applied. Then the regular
717 expression will match on <code>/home/abc/public_html/abc</code> and
718 the corresponding <directive type="section">Directory</directive> will
721 <p><strong>Note that the default Apache access for
722 <code><Directory /></code> is <code>Allow from All</code>.
723 This means that Apache will serve any file mapped from an URL. It is
724 recommended that you change this with a block such
728 <Directory /><br />
730 Order Deny,Allow<br />
736 <p><strong>and then override this for directories you
737 <em>want</em> accessible. See the <a
738 href="../misc/security_tips.html">Security Tips</a> page for more
739 details.</strong></p>
741 <p>The directory sections occur in the <code>httpd.conf</code> file.
742 <directive type="section">Directory</directive> directives
743 cannot nest, and cannot appear in a <directive module="core"
744 type="section">Limit</directive> or <directive module="core"
745 type="section">LimitExcept</directive> section.</p>
747 <seealso><a href="../sections.html">How <Directory>,
748 <Location> and <Files> sections work</a> for an
749 explanation of how these different sections are combined when a
750 request is received</seealso>
753 <directivesynopsis type="section">
754 <name>DirectoryMatch</name>
755 <description>Enclose directives that apply to
756 file-system directories matching a regular expression and their
757 subdirectories</description>
758 <syntax><DirectoryMatch <var>regex</var>>
759 ... </DirectoryMatch></syntax>
760 <contextlist><context>server config</context><context>virtual host</context>
764 <p><directive type="section">DirectoryMatch</directive> and
765 <code></DirectoryMatch></code> are used to enclose a group
766 of directives which will apply only to the named directory and
767 sub-directories of that directory, the same as <directive
768 module="core" type="section">Directory</directive>. However, it
769 takes as an argument a <glossary ref="regex">regular
770 expression</glossary>. For example:</p>
773 <DirectoryMatch "^/www/(.+/)?[0-9]{3}">
776 <p>would match directories in <code>/www/</code> that consisted of three
779 <seealso><directive type="section" module="core">Directory</directive> for
780 a description of how regular expressions are mixed in with normal
781 <directive type="section">Directory</directive>s</seealso>
783 href="../sections.html">How <Directory>, <Location> and
784 <Files> sections work</a> for an explanation of how these different
785 sections are combined when a request is received</seealso>
789 <name>DocumentRoot</name>
790 <description>Directory that forms the main document tree visible
791 from the web</description>
792 <syntax>DocumentRoot <var>directory-path</var></syntax>
793 <default>DocumentRoot /usr/local/apache/htdocs</default>
794 <contextlist><context>server config</context><context>virtual host</context>
798 <p>This directive sets the directory from which <program>httpd</program>
799 will serve files. Unless matched by a directive like <directive
800 module="mod_alias">Alias</directive>, the server appends the
801 path from the requested URL to the document root to make the
802 path to the document. Example:</p>
805 DocumentRoot /usr/web
809 <code>http://www.my.host.com/index.html</code> refers to
810 <code>/usr/web/index.html</code>. If the <var>directory-path</var> is
811 not absolute then it is assumed to be relative to the <directive
812 module="core">ServerRoot</directive>.</p>
814 <p>The <directive>DocumentRoot</directive> should be specified without
815 a trailing slash.</p>
817 <seealso><a href="../urlmapping.html#documentroot">Mapping URLs to Filesystem
818 Locations</a></seealso>
822 <name>EnableMMAP</name>
823 <description>Use memory-mapping to read files during delivery</description>
824 <syntax>EnableMMAP On|Off</syntax>
825 <default>EnableMMAP On</default>
826 <contextlist><context>server config</context><context>virtual host</context>
827 <context>directory</context><context>.htaccess</context>
829 <override>FileInfo</override>
832 <p>This directive controls whether the <program>httpd</program> may use
833 memory-mapping if it needs to read the contents of a file during
834 delivery. By default, when the handling of a request requires
835 access to the data within a file -- for example, when delivering a
836 server-parsed file using <module>mod_include</module> -- Apache
837 memory-maps the file if the OS supports it.</p>
839 <p>This memory-mapping sometimes yields a performance improvement.
840 But in some environments, it is better to disable the memory-mapping
841 to prevent operational problems:</p>
844 <li>On some multiprocessor systems, memory-mapping can reduce the
845 performance of the <program>httpd</program>.</li>
846 <li>Deleting or truncating a file while <program>httpd</program>
847 has it memory-mapped can cause <program>httpd</program> to
848 crash with a segmentation fault.
852 <p>For server configurations that are vulnerable to these problems,
853 you should disable memory-mapping of delivered files by specifying:</p>
859 <p>For NFS mounted files, this feature may be disabled explicitly for
860 the offending files by specifying:</p>
863 <Directory "/path-to-nfs-files">
873 <name>EnableSendfile</name>
874 <description>Use the kernel sendfile support to deliver files to the client</description>
875 <syntax>EnableSendfile On|Off</syntax>
876 <default>EnableSendfile On</default>
877 <contextlist><context>server config</context><context>virtual host</context>
878 <context>directory</context><context>.htaccess</context>
880 <override>FileInfo</override>
881 <compatibility>Available in version 2.0.44 and later</compatibility>
884 <p>This directive controls whether <program>httpd</program> may use the
885 sendfile support from the kernel to transmit file contents to the client.
886 By default, when the handling of a request requires no access
887 to the data within a file -- for example, when delivering a
888 static file -- Apache uses sendfile to deliver the file contents
889 without ever reading the file if the OS supports it.</p>
891 <p>This sendfile mechanism avoids separate read and send operations,
892 and buffer allocations. But on some platforms or within some
893 filesystems, it is better to disable this feature to avoid
894 operational problems:</p>
897 <li>Some platforms may have broken sendfile support that the build
898 system did not detect, especially if the binaries were built on
899 another box and moved to such a machine with broken sendfile
901 <li>On Linux the use of sendfile triggers TCP-checksum
902 offloading bugs on certain networking cards when using IPv6.</li>
903 <li>On Linux on Itanium, sendfile may be unable to handle files
904 over 2GB in size.</li>
905 <li>With a network-mounted <directive
906 module="core">DocumentRoot</directive> (e.g., NFS or SMB),
907 the kernel may be unable to serve the network file through
911 <p>For server configurations that are vulnerable to these problems,
912 you should disable this feature by specifying:</p>
918 <p>For NFS or SMB mounted files, this feature may be disabled explicitly
919 for the offending files by specifying:</p>
922 <Directory "/path-to-nfs-files">
928 <p>Please note that the per-directory and .htaccess configuration
929 of <directive>EnableSendfile</directive> is not supported by
930 <module>mod_disk_cache</module>.
931 Only global definition of <directive>EnableSendfile</directive>
932 is taken into account by the module.
938 <name>ErrorDocument</name>
939 <description>What the server will return to the client
940 in case of an error</description>
941 <syntax>ErrorDocument <var>error-code</var> <var>document</var></syntax>
942 <contextlist><context>server config</context><context>virtual host</context>
943 <context>directory</context><context>.htaccess</context>
945 <override>FileInfo</override>
946 <compatibility>Quoting syntax for text messages is different in Apache
950 <p>In the event of a problem or error, Apache can be configured
951 to do one of four things,</p>
954 <li>output a simple hardcoded error message</li>
956 <li>output a customized message</li>
958 <li>redirect to a local <var>URL-path</var> to handle the
961 <li>redirect to an external <var>URL</var> to handle the
965 <p>The first option is the default, while options 2-4 are
966 configured using the <directive>ErrorDocument</directive>
967 directive, which is followed by the HTTP response code and a URL
968 or a message. Apache will sometimes offer additional information
969 regarding the problem/error.</p>
971 <p>URLs can begin with a slash (/) for local web-paths (relative
972 to the <directive module="core">DocumentRoot</directive>), or be a
973 full URL which the client can resolve. Alternatively, a message
974 can be provided to be displayed by the browser. Examples:</p>
977 ErrorDocument 500 http://foo.example.com/cgi-bin/tester<br />
978 ErrorDocument 404 /cgi-bin/bad_urls.pl<br />
979 ErrorDocument 401 /subscription_info.html<br />
980 ErrorDocument 403 "Sorry can't allow you access today"
983 <p>Additionally, the special value <code>default</code> can be used
984 to specify Apache's simple hardcoded message. While not required
985 under normal circumstances, <code>default</code> will restore
986 Apache's simple hardcoded message for configurations that would
987 otherwise inherit an existing <directive>ErrorDocument</directive>.</p>
990 ErrorDocument 404 /cgi-bin/bad_urls.pl<br /><br />
991 <Directory /web/docs><br />
993 ErrorDocument 404 default<br />
998 <p>Note that when you specify an <directive>ErrorDocument</directive>
999 that points to a remote URL (ie. anything with a method such as
1000 <code>http</code> in front of it), Apache will send a redirect to the
1001 client to tell it where to find the document, even if the
1002 document ends up being on the same server. This has several
1003 implications, the most important being that the client will not
1004 receive the original error status code, but instead will
1005 receive a redirect status code. This in turn can confuse web
1006 robots and other clients which try to determine if a URL is
1007 valid using the status code. In addition, if you use a remote
1008 URL in an <code>ErrorDocument 401</code>, the client will not
1009 know to prompt the user for a password since it will not
1010 receive the 401 status code. Therefore, <strong>if you use an
1011 <code>ErrorDocument 401</code> directive then it must refer to a local
1012 document.</strong></p>
1014 <p>Microsoft Internet Explorer (MSIE) will by default ignore
1015 server-generated error messages when they are "too small" and substitute
1016 its own "friendly" error messages. The size threshold varies depending on
1017 the type of error, but in general, if you make your error document
1018 greater than 512 bytes, then MSIE will show the server-generated
1019 error rather than masking it. More information is available in
1020 Microsoft Knowledge Base article <a
1021 href="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q294807"
1024 <p>Although most error messages can be overriden, there are certain
1025 circumstances where the internal messages are used regardless of the
1026 setting of <directive module="core">ErrorDocument</directive>. In
1027 particular, if a malformed request is detected, normal request processing
1028 will be immediately halted and the internal error message returned.
1029 This is necessary to guard against security problems caused by
1032 <p>Prior to version 2.0, messages were indicated by prefixing
1033 them with a single unmatched double quote character.</p>
1036 <seealso><a href="../custom-error.html">documentation of
1037 customizable responses</a></seealso>
1038 </directivesynopsis>
1041 <name>ErrorLog</name>
1042 <description>Location where the server will log errors</description>
1043 <syntax> ErrorLog <var>file-path</var>|syslog[:<var>facility</var>]</syntax>
1044 <default>ErrorLog logs/error_log (Unix) ErrorLog logs/error.log (Windows)</default>
1045 <contextlist><context>server config</context><context>virtual host</context>
1049 <p>The <directive>ErrorLog</directive> directive sets the name of
1050 the file to which the server will log any errors it encounters. If
1051 the <var>file-path</var> is not absolute then it is assumed to be
1052 relative to the <directive module="core">ServerRoot</directive>.</p>
1054 <example><title>Example</title>
1055 ErrorLog /var/log/httpd/error_log
1058 <p>If the <var>file-path</var>
1059 begins with a pipe (|) then it is assumed to be a command to spawn
1060 to handle the error log.</p>
1062 <example><title>Example</title>
1063 ErrorLog "|/usr/local/bin/httpd_errors"
1066 <p>Using <code>syslog</code> instead of a filename enables logging
1067 via syslogd(8) if the system supports it. The default is to use
1068 syslog facility <code>local7</code>, but you can override this by
1069 using the <code>syslog:<var>facility</var></code> syntax where
1070 <var>facility</var> can be one of the names usually documented in
1073 <example><title>Example</title>
1074 ErrorLog syslog:user
1077 <p>SECURITY: See the <a
1078 href="../misc/security_tips.html#serverroot">security tips</a>
1079 document for details on why your security could be compromised
1080 if the directory where log files are stored is writable by
1081 anyone other than the user that starts the server.</p>
1082 <note type="warning"><title>Note</title>
1083 <p>When entering a file path on non-Unix platforms, care should be taken
1084 to make sure that only forward slashed are used even though the platform
1085 may allow the use of back slashes. In general it is a good idea to always
1086 use forward slashes throughout the configuration files.</p>
1089 <seealso><directive module="core">LogLevel</directive></seealso>
1090 <seealso><a href="../logs.html">Apache Log Files</a></seealso>
1091 </directivesynopsis>
1094 <name>FileETag</name>
1095 <description>File attributes used to create the ETag
1096 HTTP response header</description>
1097 <syntax>FileETag <var>component</var> ...</syntax>
1098 <default>FileETag INode MTime Size</default>
1099 <contextlist><context>server config</context><context>virtual host</context>
1100 <context>directory</context><context>.htaccess</context>
1102 <override>FileInfo</override>
1106 The <directive>FileETag</directive> directive configures the file
1107 attributes that are used to create the <code>ETag</code> (entity
1108 tag) response header field when the document is based on a file.
1109 (The <code>ETag</code> value is used in cache management to save
1110 network bandwidth.) In Apache 1.3.22 and earlier, the
1111 <code>ETag</code> value was <em>always</em> formed
1112 from the file's inode, size, and last-modified time (mtime). The
1113 <directive>FileETag</directive> directive allows you to choose
1114 which of these -- if any -- should be used. The recognized keywords are:
1118 <dt><strong>INode</strong></dt>
1119 <dd>The file's i-node number will be included in the calculation</dd>
1120 <dt><strong>MTime</strong></dt>
1121 <dd>The date and time the file was last modified will be included</dd>
1122 <dt><strong>Size</strong></dt>
1123 <dd>The number of bytes in the file will be included</dd>
1124 <dt><strong>All</strong></dt>
1125 <dd>All available fields will be used. This is equivalent to:
1126 <example>FileETag INode MTime Size</example></dd>
1127 <dt><strong>None</strong></dt>
1128 <dd>If a document is file-based, no <code>ETag</code> field will be
1129 included in the response</dd>
1132 <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
1133 keywords may be prefixed with either <code>+</code> or <code>-</code>,
1134 which allow changes to be made to the default setting inherited
1135 from a broader scope. Any keyword appearing without such a prefix
1136 immediately and completely cancels the inherited setting.</p>
1138 <p>If a directory's configuration includes
1139 <code>FileETag INode MTime Size</code>, and a
1140 subdirectory's includes <code>FileETag -INode</code>,
1141 the setting for that subdirectory (which will be inherited by
1142 any sub-subdirectories that don't override it) will be equivalent to
1143 <code>FileETag MTime Size</code>.</p>
1144 <note type="warning"><title>Warning</title>
1145 Do not change the default for directories or locations that have WebDAV
1146 enabled and use <module>mod_dav_fs</module> as a storage provider.
1147 <module>mod_dav_fs</module> uses <code>INode MTime Size</code>
1148 as a fixed format for <code>ETag</code> comparisons on conditional requests.
1149 These conditional requests will break if the <code>ETag</code> format is
1150 changed via <directive>FileETag</directive>.
1153 </directivesynopsis>
1155 <directivesynopsis type="section">
1157 <description>Contains directives that apply to matched
1158 filenames</description>
1159 <syntax><Files <var>filename</var>> ... </Files></syntax>
1160 <contextlist><context>server config</context><context>virtual host</context>
1161 <context>directory</context><context>.htaccess</context>
1163 <override>All</override>
1166 <p>The <directive type="section">Files</directive> directive
1167 limits the scope of the enclosed directives by filename. It is comparable
1168 to the <directive module="core" type="section">Directory</directive>
1169 and <directive module="core" type="section">Location</directive>
1170 directives. It should be matched with a <code></Files></code>
1171 directive. The directives given within this section will be applied to
1172 any object with a basename (last component of filename) matching the
1173 specified filename. <directive type="section">Files</directive>
1174 sections are processed in the order they appear in the
1175 configuration file, after the <directive module="core"
1176 type="section">Directory</directive> sections and
1177 <code>.htaccess</code> files are read, but before <directive
1178 type="section" module="core">Location</directive> sections. Note
1179 that <directive type="section">Files</directive> can be nested
1180 inside <directive type="section"
1181 module="core">Directory</directive> sections to restrict the
1182 portion of the filesystem they apply to.</p>
1184 <p>The <var>filename</var> argument should include a filename, or
1185 a wild-card string, where <code>?</code> matches any single character,
1186 and <code>*</code> matches any sequences of characters.
1187 <glossary ref="regex">Regular expressions</glossary>
1188 can also be used, with the addition of the
1189 <code>~</code> character. For example:</p>
1192 <Files ~ "\.(gif|jpe?g|png)$">
1195 <p>would match most common Internet graphics formats. <directive
1196 module="core" type="section">FilesMatch</directive> is preferred,
1199 <p>Note that unlike <directive type="section"
1200 module="core">Directory</directive> and <directive type="section"
1201 module="core">Location</directive> sections, <directive
1202 type="section">Files</directive> sections can be used inside
1203 <code>.htaccess</code> files. This allows users to control access to
1204 their own files, at a file-by-file level.</p>
1207 <seealso><a href="../sections.html">How <Directory>, <Location>
1208 and <Files> sections work</a> for an explanation of how these
1209 different sections are combined when a request is received</seealso>
1210 </directivesynopsis>
1212 <directivesynopsis type="section">
1213 <name>FilesMatch</name>
1214 <description>Contains directives that apply to regular-expression matched
1215 filenames</description>
1216 <syntax><FilesMatch <var>regex</var>> ... </FilesMatch></syntax>
1217 <contextlist><context>server config</context><context>virtual host</context>
1218 <context>directory</context><context>.htaccess</context>
1220 <override>All</override>
1223 <p>The <directive type="section">FilesMatch</directive> directive
1224 limits the scope of the enclosed directives by filename, just as the
1225 <directive module="core" type="section">Files</directive> directive
1226 does. However, it accepts a <glossary ref="regex">regular
1227 expression</glossary>. For example:</p>
1230 <FilesMatch "\.(gif|jpe?g|png)$">
1233 <p>would match most common Internet graphics formats.</p>
1236 <seealso><a href="../sections.html">How <Directory>, <Location>
1237 and <Files> sections work</a> for an explanation of how these
1238 different sections are combined when a request is received</seealso>
1239 </directivesynopsis>
1242 <name>ForceType</name>
1243 <description>Forces all matching files to be served with the specified
1244 media type in the HTTP Content-Type header field</description>
1245 <syntax>ForceType <var>media-type</var>|None</syntax>
1246 <contextlist><context>directory</context><context>.htaccess</context>
1248 <override>FileInfo</override>
1249 <compatibility>Moved to the core in Apache 2.0</compatibility>
1252 <p>When placed into an <code>.htaccess</code> file or a
1253 <directive type="section" module="core">Directory</directive>, or
1254 <directive type="section" module="core">Location</directive> or
1255 <directive type="section" module="core">Files</directive>
1256 section, this directive forces all matching files to be served
1257 with the content type identification given by
1258 <var>media-type</var>. For example, if you had a directory full of
1259 GIF files, but did not want to label them all with <code>.gif</code>,
1260 you might want to use:</p>
1266 <p>Note that this directive overrides other indirect media type
1267 associations defined in mime.types or via the
1268 <directive module="mod_mime">AddType</directive>.</p>
1270 <p>You can also override more general
1271 <directive>ForceType</directive> settings
1272 by using the value of <code>None</code>:</p>
1275 # force all files to be image/gif:<br />
1276 <Location /images><br />
1278 ForceType image/gif<br />
1280 </Location><br />
1282 # but normal mime-type associations here:<br />
1283 <Location /images/mixed><br />
1285 ForceType None<br />
1290 </directivesynopsis>
1293 <name>HostnameLookups</name>
1294 <description>Enables DNS lookups on client IP addresses</description>
1295 <syntax>HostnameLookups On|Off|Double</syntax>
1296 <default>HostnameLookups Off</default>
1297 <contextlist><context>server config</context><context>virtual host</context>
1298 <context>directory</context></contextlist>
1301 <p>This directive enables DNS lookups so that host names can be
1302 logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
1303 The value <code>Double</code> refers to doing double-reverse
1304 DNS lookup. That is, after a reverse lookup is performed, a forward
1305 lookup is then performed on that result. At least one of the IP
1306 addresses in the forward lookup must match the original
1307 address. (In "tcpwrappers" terminology this is called
1308 <code>PARANOID</code>.)</p>
1310 <p>Regardless of the setting, when <module>mod_authz_host</module> is
1311 used for controlling access by hostname, a double reverse lookup
1312 will be performed. This is necessary for security. Note that the
1313 result of this double-reverse isn't generally available unless you
1314 set <code>HostnameLookups Double</code>. For example, if only
1315 <code>HostnameLookups On</code> and a request is made to an object
1316 that is protected by hostname restrictions, regardless of whether
1317 the double-reverse fails or not, CGIs will still be passed the
1318 single-reverse result in <code>REMOTE_HOST</code>.</p>
1320 <p>The default is <code>Off</code> in order to save the network
1321 traffic for those sites that don't truly need the reverse
1322 lookups done. It is also better for the end users because they
1323 don't have to suffer the extra latency that a lookup entails.
1324 Heavily loaded sites should leave this directive
1325 <code>Off</code>, since DNS lookups can take considerable
1326 amounts of time. The utility <program>logresolve</program>, compiled by
1327 default to the <code>bin</code> subdirectory of your installation
1328 directory, can be used to look up host names from logged IP addresses
1331 </directivesynopsis>
1333 <directivesynopsis type="section">
1335 <description>Contains directives that apply only if a condition is
1336 satisfied by a request at runtime</description>
1337 <syntax><If <var>expression</var>> ... </If></syntax>
1338 <contextlist><context>server config</context><context>virtual host</context>
1339 <context>directory</context><context>.htaccess</context>
1341 <override>All</override>
1344 <p>The <directive type="section">If</directive> directive
1345 evaluates an expression at runtime, and applies the enclosed
1346 directives if and only if the expression evaluates to true.
1350 <If "$req{Host} = ''">
1353 <p>would match HTTP/1.0 requests without a <var>Host:</var> header.</p>
1355 <p>You may compare the value of any variable in the request headers
1356 ($req), response headers ($resp) or environment ($env) in your
1360 <seealso><a href="../sections.html">How <Directory>, <Location>,
1361 <Files> sections work</a> for an explanation of how these
1362 different sections are combined when a request is received.
1363 <directive type="section">If</directive> has the same precedence
1364 and usage as <directive type="section">Files</directive></seealso>
1365 </directivesynopsis>
1367 <directivesynopsis type="section">
1368 <name>IfDefine</name>
1369 <description>Encloses directives that will be processed only
1370 if a test is true at startup</description>
1371 <syntax><IfDefine [!]<var>parameter-name</var>> ...
1372 </IfDefine></syntax>
1373 <contextlist><context>server config</context><context>virtual host</context>
1374 <context>directory</context><context>.htaccess</context>
1376 <override>All</override>
1379 <p>The <code><IfDefine <var>test</var>>...</IfDefine>
1380 </code> section is used to mark directives that are conditional. The
1381 directives within an <directive type="section">IfDefine</directive>
1382 section are only processed if the <var>test</var> is true. If <var>
1383 test</var> is false, everything between the start and end markers is
1386 <p>The <var>test</var> in the <directive type="section"
1387 >IfDefine</directive> section directive can be one of two forms:</p>
1390 <li><var>parameter-name</var></li>
1392 <li><code>!</code><var>parameter-name</var></li>
1395 <p>In the former case, the directives between the start and end
1396 markers are only processed if the parameter named
1397 <var>parameter-name</var> is defined. The second format reverses
1398 the test, and only processes the directives if
1399 <var>parameter-name</var> is <strong>not</strong> defined.</p>
1401 <p>The <var>parameter-name</var> argument is a define as given on the
1402 <program>httpd</program> command line via <code>-D<var>parameter</var>
1403 </code> at the time the server was started or by the <directive
1404 module="core">Define</directive> directive.</p>
1406 <p><directive type="section">IfDefine</directive> sections are
1407 nest-able, which can be used to implement simple
1408 multiple-parameter tests. Example:</p>
1411 httpd -DReverseProxy -DUseCache -DMemCache ...<br />
1414 <IfDefine ReverseProxy><br />
1416 LoadModule proxy_module modules/mod_proxy.so<br />
1417 LoadModule proxy_http_module modules/mod_proxy_http.so<br />
1418 <IfDefine UseCache><br />
1420 LoadModule cache_module modules/mod_cache.so<br />
1421 <IfDefine MemCache><br />
1423 LoadModule mem_cache_module modules/mod_mem_cache.so<br />
1425 </IfDefine><br />
1426 <IfDefine !MemCache><br />
1428 LoadModule disk_cache_module modules/mod_disk_cache.so<br />
1437 </directivesynopsis>
1439 <directivesynopsis type="section">
1440 <name>IfModule</name>
1441 <description>Encloses directives that are processed conditional on the
1442 presence or absence of a specific module</description>
1443 <syntax><IfModule [!]<var>module-file</var>|<var>module-identifier</var>> ...
1444 </IfModule></syntax>
1445 <contextlist><context>server config</context><context>virtual host</context>
1446 <context>directory</context><context>.htaccess</context>
1448 <override>All</override>
1449 <compatibility>Module identifiers are available in version 2.1 and
1450 later.</compatibility>
1453 <p>The <code><IfModule <var>test</var>>...</IfModule></code>
1454 section is used to mark directives that are conditional on the presence of
1455 a specific module. The directives within an <directive type="section"
1456 >IfModule</directive> section are only processed if the <var>test</var>
1457 is true. If <var>test</var> is false, everything between the start and
1458 end markers is ignored.</p>
1460 <p>The <var>test</var> in the <directive type="section"
1461 >IfModule</directive> section directive can be one of two forms:</p>
1464 <li><var>module</var></li>
1466 <li>!<var>module</var></li>
1469 <p>In the former case, the directives between the start and end
1470 markers are only processed if the module named <var>module</var>
1471 is included in Apache -- either compiled in or
1472 dynamically loaded using <directive module="mod_so"
1473 >LoadModule</directive>. The second format reverses the test,
1474 and only processes the directives if <var>module</var> is
1475 <strong>not</strong> included.</p>
1477 <p>The <var>module</var> argument can be either the module identifier or
1478 the file name of the module, at the time it was compiled. For example,
1479 <code>rewrite_module</code> is the identifier and
1480 <code>mod_rewrite.c</code> is the file name. If a module consists of
1481 several source files, use the name of the file containing the string
1482 <code>STANDARD20_MODULE_STUFF</code>.</p>
1484 <p><directive type="section">IfModule</directive> sections are
1485 nest-able, which can be used to implement simple multiple-module
1488 <note>This section should only be used if you need to have one
1489 configuration file that works whether or not a specific module
1490 is available. In normal operation, directives need not be
1491 placed in <directive type="section">IfModule</directive>
1494 </directivesynopsis>
1497 <name>Include</name>
1498 <description>Includes other configuration files from within
1499 the server configuration files</description>
1500 <syntax>Include <var>file-path</var>|<var>directory-path</var></syntax>
1501 <contextlist><context>server config</context><context>virtual host</context>
1502 <context>directory</context>
1504 <compatibility>Wildcard matching available in 2.0.41 and later</compatibility>
1507 <p>This directive allows inclusion of other configuration files
1508 from within the server configuration files.</p>
1510 <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used to
1511 include several files at once, in alphabetical order. In
1512 addition, if <directive>Include</directive> points to a directory,
1513 rather than a file, Apache will read all files in that directory
1514 and any subdirectory. However, including entire directories is not
1515 recommended, because it is easy to accidentally leave temporary
1516 files in a directory that can cause <program>httpd</program> to
1517 fail. Instead, we encourage you to use the wildcard syntax shown
1518 below, to include files that match a particular pattern, such as
1519 *.conf, for example.</p>
1521 <p>The file path specified may be an absolute path, or may be relative
1522 to the <directive module="core">ServerRoot</directive> directory.</p>
1527 Include /usr/local/apache2/conf/ssl.conf<br />
1528 Include /usr/local/apache2/conf/vhosts/*.conf
1531 <p>Or, providing paths relative to your <directive
1532 module="core">ServerRoot</directive> directory:</p>
1535 Include conf/ssl.conf<br />
1536 Include conf/vhosts/*.conf
1540 <seealso><program>apachectl</program></seealso>
1541 </directivesynopsis>
1544 <name>KeepAlive</name>
1545 <description>Enables HTTP persistent connections</description>
1546 <syntax>KeepAlive On|Off</syntax>
1547 <default>KeepAlive On</default>
1548 <contextlist><context>server config</context><context>virtual host</context>
1552 <p>The Keep-Alive extension to HTTP/1.0 and the persistent
1553 connection feature of HTTP/1.1 provide long-lived HTTP sessions
1554 which allow multiple requests to be sent over the same TCP
1555 connection. In some cases this has been shown to result in an
1556 almost 50% speedup in latency times for HTML documents with
1557 many images. To enable Keep-Alive connections, set
1558 <code>KeepAlive On</code>.</p>
1560 <p>For HTTP/1.0 clients, Keep-Alive connections will only be
1561 used if they are specifically requested by a client. In
1562 addition, a Keep-Alive connection with an HTTP/1.0 client can
1563 only be used when the length of the content is known in
1564 advance. This implies that dynamic content such as CGI output,
1565 SSI pages, and server-generated directory listings will
1566 generally not use Keep-Alive connections to HTTP/1.0 clients.
1567 For HTTP/1.1 clients, persistent connections are the default
1568 unless otherwise specified. If the client requests it, chunked
1569 encoding will be used in order to send content of unknown
1570 length over persistent connections.</p>
1572 <p>When a client uses a Keep-Alive connection it will be counted
1573 as a single "request" for the <directive module="mpm_common"
1574 >MaxRequestsPerChild</directive> directive, regardless
1575 of how many requests are sent using the connection.</p>
1578 <seealso><directive module="core">MaxKeepAliveRequests</directive></seealso>
1579 </directivesynopsis>
1582 <name>KeepAliveTimeout</name>
1583 <description>Amount of time the server will wait for subsequent
1584 requests on a persistent connection</description>
1585 <syntax>KeepAliveTimeout <var>num</var>[ms]</syntax>
1586 <default>KeepAliveTimeout 5</default>
1587 <contextlist><context>server config</context><context>virtual host</context>
1589 <compatibility>Specifying a value in milliseconds is available in
1590 Apache 2.3.2 and later</compatibility>
1593 <p>The number of seconds Apache will wait for a subsequent
1594 request before closing the connection. By adding a postfix of ms the
1595 timeout can be also set in milliseconds. Once a request has been
1596 received, the timeout value specified by the
1597 <directive module="core">Timeout</directive> directive applies.</p>
1599 <p>Setting <directive>KeepAliveTimeout</directive> to a high value
1600 may cause performance problems in heavily loaded servers. The
1601 higher the timeout, the more server processes will be kept
1602 occupied waiting on connections with idle clients.</p>
1604 <p>In a name-based virtual host context, the value of the first
1605 defined virtual host (the default host) in a set of <directive
1606 module="core">NameVirtualHost</directive> will be used.
1607 The other values will be ignored.</p>
1609 </directivesynopsis>
1611 <directivesynopsis type="section">
1613 <description>Restrict enclosed access controls to only certain HTTP
1614 methods</description>
1615 <syntax><Limit <var>method</var> [<var>method</var>] ... > ...
1616 </Limit></syntax>
1617 <contextlist><context>directory</context><context>.htaccess</context>
1619 <override>AuthConfig, Limit</override>
1622 <p>Access controls are normally effective for
1623 <strong>all</strong> access methods, and this is the usual
1624 desired behavior. <strong>In the general case, access control
1625 directives should not be placed within a
1626 <directive type="section">Limit</directive> section.</strong></p>
1628 <p>The purpose of the <directive type="section">Limit</directive>
1629 directive is to restrict the effect of the access controls to the
1630 nominated HTTP methods. For all other methods, the access
1631 restrictions that are enclosed in the <directive
1632 type="section">Limit</directive> bracket <strong>will have no
1633 effect</strong>. The following example applies the access control
1634 only to the methods <code>POST</code>, <code>PUT</code>, and
1635 <code>DELETE</code>, leaving all other methods unprotected:</p>
1638 <Limit POST PUT DELETE><br />
1640 Require valid-user<br />
1645 <p>The method names listed can be one or more of: <code>GET</code>,
1646 <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
1647 <code>CONNECT</code>, <code>OPTIONS</code>,
1648 <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
1649 <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
1650 <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
1651 case-sensitive.</strong> If <code>GET</code> is used it will also
1652 restrict <code>HEAD</code> requests. The <code>TRACE</code> method
1653 cannot be limited (see <directive module="core"
1654 >TraceEnable</directive>).</p>
1656 <note type="warning">A <directive type="section"
1657 module="core">LimitExcept</directive> section should always be
1658 used in preference to a <directive type="section">Limit</directive>
1659 section when restricting access, since a <directive type="section"
1660 module="core">LimitExcept</directive> section provides protection
1661 against arbitrary methods.</note>
1663 <p>The <directive type="section">Limit</directive> and
1664 <directive type="section" module="core">LimitExcept</directive>
1665 directives may be nested. In this case, each successive level of
1666 <directive type="section">Limit</directive> or <directive
1667 type="section" module="core">LimitExcept</directive> directives must
1668 further restrict the set of methods to which access controls apply.</p>
1670 <note type="warning">When using
1671 <directive type="section">Limit</directive> or
1672 <directive type="section">LimitExcept</directive> directives with
1673 the <directive module="mod_authz_core">Require</directive> directive,
1674 note that the first <directive module="mod_authz_core">Require</directive>
1675 to succeed authorizes the request, regardless of the presence of other
1676 <directive module="mod_authz_core">Require</directive> directives.</note>
1678 <p>For example, given the following configuration, all users will
1679 be authorized for <code>POST</code> requests, and the
1680 <code>Require group editors</code> directive will be ignored
1684 <LimitExcept GET>
1688 </LimitExcept><br />
1691 Require group editors
1696 </directivesynopsis>
1698 <directivesynopsis type="section">
1699 <name>LimitExcept</name>
1700 <description>Restrict access controls to all HTTP methods
1701 except the named ones</description>
1702 <syntax><LimitExcept <var>method</var> [<var>method</var>] ... > ...
1703 </LimitExcept></syntax>
1704 <contextlist><context>directory</context><context>.htaccess</context>
1706 <override>AuthConfig, Limit</override>
1709 <p><directive type="section">LimitExcept</directive> and
1710 <code></LimitExcept></code> are used to enclose
1711 a group of access control directives which will then apply to any
1712 HTTP access method <strong>not</strong> listed in the arguments;
1713 i.e., it is the opposite of a <directive type="section"
1714 module="core">Limit</directive> section and can be used to control
1715 both standard and nonstandard/unrecognized methods. See the
1716 documentation for <directive module="core"
1717 type="section">Limit</directive> for more details.</p>
1722 <LimitExcept POST GET><br />
1724 Require valid-user<br />
1726 </LimitExcept>
1730 </directivesynopsis>
1733 <name>LimitInternalRecursion</name>
1734 <description>Determine maximum number of internal redirects and nested
1735 subrequests</description>
1736 <syntax>LimitInternalRecursion <var>number</var> [<var>number</var>]</syntax>
1737 <default>LimitInternalRecursion 10</default>
1738 <contextlist><context>server config</context><context>virtual host</context>
1740 <compatibility>Available in Apache 2.0.47 and later</compatibility>
1743 <p>An internal redirect happens, for example, when using the <directive
1744 module="mod_actions">Action</directive> directive, which internally
1745 redirects the original request to a CGI script. A subrequest is Apache's
1746 mechanism to find out what would happen for some URI if it were requested.
1747 For example, <module>mod_dir</module> uses subrequests to look for the
1748 files listed in the <directive module="mod_dir">DirectoryIndex</directive>
1751 <p><directive>LimitInternalRecursion</directive> prevents the server
1752 from crashing when entering an infinite loop of internal redirects or
1753 subrequests. Such loops are usually caused by misconfigurations.</p>
1755 <p>The directive stores two different limits, which are evaluated on
1756 per-request basis. The first <var>number</var> is the maximum number of
1757 internal redirects, that may follow each other. The second <var>number</var>
1758 determines, how deep subrequests may be nested. If you specify only one
1759 <var>number</var>, it will be assigned to both limits.</p>
1761 <example><title>Example</title>
1762 LimitInternalRecursion 5
1765 </directivesynopsis>
1768 <name>LimitRequestBody</name>
1769 <description>Restricts the total size of the HTTP request body sent
1770 from the client</description>
1771 <syntax>LimitRequestBody <var>bytes</var></syntax>
1772 <default>LimitRequestBody 0</default>
1773 <contextlist><context>server config</context><context>virtual host</context>
1774 <context>directory</context><context>.htaccess</context>
1776 <override>All</override>
1779 <p>This directive specifies the number of <var>bytes</var> from 0
1780 (meaning unlimited) to 2147483647 (2GB) that are allowed in a
1783 <p>The <directive>LimitRequestBody</directive> directive allows
1784 the user to set a limit on the allowed size of an HTTP request
1785 message body within the context in which the directive is given
1786 (server, per-directory, per-file or per-location). If the client
1787 request exceeds that limit, the server will return an error
1788 response instead of servicing the request. The size of a normal
1789 request message body will vary greatly depending on the nature of
1790 the resource and the methods allowed on that resource. CGI scripts
1791 typically use the message body for retrieving form information.
1792 Implementations of the <code>PUT</code> method will require
1793 a value at least as large as any representation that the server
1794 wishes to accept for that resource.</p>
1796 <p>This directive gives the server administrator greater
1797 control over abnormal client request behavior, which may be
1798 useful for avoiding some forms of denial-of-service
1801 <p>If, for example, you are permitting file upload to a particular
1802 location, and wish to limit the size of the uploaded file to 100K,
1803 you might use the following directive:</p>
1806 LimitRequestBody 102400
1810 </directivesynopsis>
1813 <name>LimitRequestFields</name>
1814 <description>Limits the number of HTTP request header fields that
1815 will be accepted from the client</description>
1816 <syntax>LimitRequestFields <var>number</var></syntax>
1817 <default>LimitRequestFields 100</default>
1818 <contextlist><context>server config</context></contextlist>
1821 <p><var>Number</var> is an integer from 0 (meaning unlimited) to
1822 32767. The default value is defined by the compile-time
1823 constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
1826 <p>The <directive>LimitRequestFields</directive> directive allows
1827 the server administrator to modify the limit on the number of
1828 request header fields allowed in an HTTP request. A server needs
1829 this value to be larger than the number of fields that a normal
1830 client request might include. The number of request header fields
1831 used by a client rarely exceeds 20, but this may vary among
1832 different client implementations, often depending upon the extent
1833 to which a user has configured their browser to support detailed
1834 content negotiation. Optional HTTP extensions are often expressed
1835 using request header fields.</p>
1837 <p>This directive gives the server administrator greater
1838 control over abnormal client request behavior, which may be
1839 useful for avoiding some forms of denial-of-service attacks.
1840 The value should be increased if normal clients see an error
1841 response from the server that indicates too many fields were
1842 sent in the request.</p>
1847 LimitRequestFields 50
1851 </directivesynopsis>
1854 <name>LimitRequestFieldSize</name>
1855 <description>Limits the size of the HTTP request header allowed from the
1856 client</description>
1857 <syntax>LimitRequestFieldSize <var>bytes</var></syntax>
1858 <default>LimitRequestFieldSize 8190</default>
1859 <contextlist><context>server config</context></contextlist>
1862 <p>This directive specifies the number of <var>bytes</var>
1863 that will be allowed in an HTTP request header.</p>
1865 <p>The <directive>LimitRequestFieldSize</directive> directive
1866 allows the server administrator to reduce or increase the limit
1867 on the allowed size of an HTTP request header field. A server
1868 needs this value to be large enough to hold any one header field
1869 from a normal client request. The size of a normal request header
1870 field will vary greatly among different client implementations,
1871 often depending upon the extent to which a user has configured
1872 their browser to support detailed content negotiation. SPNEGO
1873 authentication headers can be up to 12392 bytes.</p>
1875 <p>This directive gives the server administrator greater
1876 control over abnormal client request behavior, which may be
1877 useful for avoiding some forms of denial-of-service attacks.</p>
1882 LimitRequestFieldSize 4094
1885 <note>Under normal conditions, the value should not be changed from
1889 </directivesynopsis>
1892 <name>LimitRequestLine</name>
1893 <description>Limit the size of the HTTP request line that will be accepted
1894 from the client</description>
1895 <syntax>LimitRequestLine <var>bytes</var></syntax>
1896 <default>LimitRequestLine 8190</default>
1897 <contextlist><context>server config</context></contextlist>
1900 <p>This directive sets the number of <var>bytes</var> that will be
1901 allowed on the HTTP request-line.</p>
1903 <p>The <directive>LimitRequestLine</directive> directive allows
1904 the server administrator to reduce or increase the limit on the allowed size
1905 of a client's HTTP request-line. Since the request-line consists of the
1906 HTTP method, URI, and protocol version, the
1907 <directive>LimitRequestLine</directive> directive places a
1908 restriction on the length of a request-URI allowed for a request
1909 on the server. A server needs this value to be large enough to
1910 hold any of its resource names, including any information that
1911 might be passed in the query part of a <code>GET</code> request.</p>
1913 <p>This directive gives the server administrator greater
1914 control over abnormal client request behavior, which may be
1915 useful for avoiding some forms of denial-of-service attacks.</p>
1920 LimitRequestLine 4094
1923 <note>Under normal conditions, the value should not be changed from
1926 </directivesynopsis>
1929 <name>LimitXMLRequestBody</name>
1930 <description>Limits the size of an XML-based request body</description>
1931 <syntax>LimitXMLRequestBody <var>bytes</var></syntax>
1932 <default>LimitXMLRequestBody 1000000</default>
1933 <contextlist><context>server config</context><context>virtual host</context>
1934 <context>directory</context><context>.htaccess</context></contextlist>
1935 <override>All</override>
1938 <p>Limit (in bytes) on maximum size of an XML-based request
1939 body. A value of <code>0</code> will disable any checking.</p>
1944 LimitXMLRequestBody 0
1948 </directivesynopsis>
1950 <directivesynopsis type="section">
1951 <name>Location</name>
1952 <description>Applies the enclosed directives only to matching
1954 <syntax><Location
1955 <var>URL-path</var>|<var>URL</var>> ... </Location></syntax>
1956 <contextlist><context>server config</context><context>virtual host</context>
1960 <p>The <directive type="section">Location</directive> directive
1961 limits the scope of the enclosed directives by URL. It is similar to the
1962 <directive type="section" module="core">Directory</directive>
1963 directive, and starts a subsection which is terminated with a
1964 <code></Location></code> directive. <directive
1965 type="section">Location</directive> sections are processed in the
1966 order they appear in the configuration file, after the <directive
1967 type="section" module="core">Directory</directive> sections and
1968 <code>.htaccess</code> files are read, and after the <directive
1969 type="section" module="core">Files</directive> sections.</p>
1971 <p><directive type="section">Location</directive> sections operate
1972 completely outside the filesystem. This has several consequences.
1973 Most importantly, <directive type="section">Location</directive>
1974 directives should not be used to control access to filesystem
1975 locations. Since several different URLs may map to the same
1976 filesystem location, such access controls may by circumvented.</p>
1978 <note><title>When to use <directive
1979 type="section">Location</directive></title>
1981 <p>Use <directive type="section">Location</directive> to apply
1982 directives to content that lives outside the filesystem. For
1983 content that lives in the filesystem, use <directive
1984 type="section" module="core">Directory</directive> and <directive
1985 type="section" module="core">Files</directive>. An exception is
1986 <code><Location /></code>, which is an easy way to
1987 apply a configuration to the entire server.</p>
1990 <p>For all origin (non-proxy) requests, the URL to be matched is a
1991 URL-path of the form <code>/path/</code>. <em>No scheme, hostname,
1992 port, or query string may be included.</em> For proxy requests, the
1993 URL to be matched is of the form
1994 <code>scheme://servername/path</code>, and you must include the
1997 <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
1998 any single character, and <code>*</code> matches any sequences of
1999 characters. Neither wildcard character matches a / in the URL-path.</p>
2001 <p><glossary ref="regex">Regular expressions</glossary>
2002 can also be used, with the addition of the <code>~</code>
2003 character. For example:</p>
2006 <Location ~ "/(extra|special)/data">
2009 <p>would match URLs that contained the substring <code>/extra/data</code>
2010 or <code>/special/data</code>. The directive <directive
2011 type="section" module="core">LocationMatch</directive> behaves
2012 identical to the regex version of <directive
2013 type="section">Location</directive>, and is preferred, for the
2014 simple reason that <code>~</code> is hard to distinguish from
2015 <code>-</code> in many fonts.</p>
2017 <p>The <directive type="section">Location</directive>
2018 functionality is especially useful when combined with the
2019 <directive module="core">SetHandler</directive>
2020 directive. For example, to enable status requests, but allow them
2021 only from browsers at <code>example.com</code>, you might use:</p>
2024 <Location /status><br />
2026 SetHandler server-status<br />
2027 Order Deny,Allow<br />
2029 Allow from .example.com<br />
2034 <note><title>Note about / (slash)</title>
2035 <p>The slash character has special meaning depending on where in a
2036 URL it appears. People may be used to its behavior in the filesystem
2037 where multiple adjacent slashes are frequently collapsed to a single
2038 slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
2039 <code>/home/foo</code>). In URL-space this is not necessarily true.
2040 The <directive type="section" module="core">LocationMatch</directive>
2041 directive and the regex version of <directive type="section"
2042 >Location</directive> require you to explicitly specify multiple
2043 slashes if that is your intention.</p>
2045 <p>For example, <code><LocationMatch ^/abc></code> would match
2046 the request URL <code>/abc</code> but not the request URL <code>
2047 //abc</code>. The (non-regex) <directive type="section"
2048 >Location</directive> directive behaves similarly when used for
2049 proxy requests. But when (non-regex) <directive type="section"
2050 >Location</directive> is used for non-proxy requests it will
2051 implicitly match multiple slashes with a single slash. For example,
2052 if you specify <code><Location /abc/def></code> and the
2053 request is to <code>/abc//def</code> then it will match.</p>
2056 <seealso><a href="../sections.html">How <Directory>, <Location>
2057 and <Files> sections work</a> for an explanation of how these
2058 different sections are combined when a request is received.</seealso>
2059 <seealso><directive module="core">LocationMatch</directive></seealso>
2060 </directivesynopsis>
2062 <directivesynopsis type="section">
2063 <name>LocationMatch</name>
2064 <description>Applies the enclosed directives only to regular-expression
2065 matching URLs</description>
2066 <syntax><LocationMatch
2067 <var>regex</var>> ... </LocationMatch></syntax>
2068 <contextlist><context>server config</context><context>virtual host</context>
2072 <p>The <directive type="section">LocationMatch</directive> directive
2073 limits the scope of the enclosed directives by URL, in an identical manner
2074 to <directive module="core" type="section">Location</directive>. However,
2075 it takes a <glossary ref="regex">regular expression</glossary>
2076 as an argument instead of a simple string. For example:</p>
2079 <LocationMatch "/(extra|special)/data">
2082 <p>would match URLs that contained the substring <code>/extra/data</code>
2083 or <code>/special/data</code>.</p>
2086 <seealso><a href="../sections.html">How <Directory>, <Location>
2087 and <Files> sections work</a> for an explanation of how these
2088 different sections are combined when a request is received</seealso>
2089 </directivesynopsis>
2092 <name>LogLevel</name>
2093 <description>Controls the verbosity of the ErrorLog</description>
2094 <syntax>LogLevel <var>level</var></syntax>
2095 <default>LogLevel warn</default>
2096 <contextlist><context>server config</context><context>virtual host</context>
2100 <p><directive>LogLevel</directive> adjusts the verbosity of the
2101 messages recorded in the error logs (see <directive
2102 module="core">ErrorLog</directive> directive). The following
2103 <var>level</var>s are available, in order of decreasing
2107 <columnspec><column width=".2"/><column width=".3"/><column width=".5"/>
2110 <th><strong>Level</strong> </th>
2112 <th><strong>Description</strong> </th>
2114 <th><strong>Example</strong> </th>
2118 <td><code>emerg</code> </td>
2120 <td>Emergencies - system is unusable.</td>
2122 <td>"Child cannot open lock file. Exiting"</td>
2126 <td><code>alert</code> </td>
2128 <td>Action must be taken immediately.</td>
2130 <td>"getpwuid: couldn't determine user name from uid"</td>
2134 <td><code>crit</code> </td>
2136 <td>Critical Conditions.</td>
2138 <td>"socket: Failed to get a socket, exiting child"</td>
2142 <td><code>error</code> </td>
2144 <td>Error conditions.</td>
2146 <td>"Premature end of script headers"</td>
2150 <td><code>warn</code> </td>
2152 <td>Warning conditions.</td>
2154 <td>"child process 1234 did not exit, sending another
2159 <td><code>notice</code> </td>
2161 <td>Normal but significant condition.</td>
2163 <td>"httpd: caught SIGBUS, attempting to dump core in
2168 <td><code>info</code> </td>
2170 <td>Informational.</td>
2172 <td>"Server seems busy, (you may need to increase
2173 StartServers, or Min/MaxSpareServers)..."</td>
2177 <td><code>debug</code> </td>
2179 <td>Debug-level messages</td>
2181 <td>"Opening config file ..."</td>
2185 <p>When a particular level is specified, messages from all
2186 other levels of higher significance will be reported as well.
2187 <em>E.g.</em>, when <code>LogLevel info</code> is specified,
2188 then messages with log levels of <code>notice</code> and
2189 <code>warn</code> will also be posted.</p>
2191 <p>Using a level of at least <code>crit</code> is
2200 <note><title>Note</title>
2201 <p>When logging to a regular file messages of the level
2202 <code>notice</code> cannot be suppressed and thus are always
2203 logged. However, this doesn't apply when logging is done
2204 using <code>syslog</code>.</p>
2207 </directivesynopsis>
2210 <name>MaxKeepAliveRequests</name>
2211 <description>Number of requests allowed on a persistent
2212 connection</description>
2213 <syntax>MaxKeepAliveRequests <var>number</var></syntax>
2214 <default>MaxKeepAliveRequests 100</default>
2215 <contextlist><context>server config</context><context>virtual host</context>
2219 <p>The <directive>MaxKeepAliveRequests</directive> directive
2220 limits the number of requests allowed per connection when
2221 <directive module="core" >KeepAlive</directive> is on. If it is
2222 set to <code>0</code>, unlimited requests will be allowed. We
2223 recommend that this setting be kept to a high value for maximum
2224 server performance.</p>
2229 MaxKeepAliveRequests 500
2232 </directivesynopsis>
2235 <name>NameVirtualHost</name>
2236 <description>Designates an IP address for name-virtual
2237 hosting</description>
2238 <syntax>NameVirtualHost <var>addr</var>[:<var>port</var>]</syntax>
2239 <contextlist><context>server config</context></contextlist>
2243 <p>A single <directive>NameVirtualHost</directive> directive
2244 identifies a set of identical virtual hosts on which the server will
2245 further select from on the basis of the <em>hostname</em>
2246 requested by the client. The <directive>NameVirtualHost</directive>
2247 directive is a required directive if you want to configure
2248 <a href="../vhosts/">name-based virtual hosts</a>.</p>
2250 <p>This directive, and the corresponding <directive >VirtualHost</directive>,
2251 <em>must</em> be qualified with a port number if the server supports both HTTP
2252 and HTTPS connections.</p>
2254 <p>Although <var>addr</var> can be a hostname, it is recommended
2255 that you always use an IP address or a wildcard. A wildcard
2256 NameVirtualHost matches only virtualhosts that also have a literal wildcard
2257 as their argument.</p>
2259 <p>In cases where a firewall or other proxy receives the requests and
2260 forwards them on a different IP address to the server, you must specify the
2261 IP address of the physical interface on the machine which will be
2262 servicing the requests. </p>
2264 <p> In the example below, requests received on interface 192.0.2.1 and port 80
2265 will only select among the first two virtual hosts. Requests received on
2266 port 80 on any other interface will only select among the third and fourth
2267 virtual hosts. In the common case where the interface isn't important
2268 to the mapping, only the "*:80" NameVirtualHost and VirtualHost directives
2272 NameVirtualHost 192.0.2.1:80<br />
2273 NameVirtualHost *:80<br /><br />
2275 <VirtualHost 192.0.2.1:80><br />
2276 ServerName namebased-a.example.com<br />
2277 </VirtualHost><br />
2279 <VirtualHost 192.0.2.1:80><br />
2280 Servername namebased-b.example.com<br />
2281 </VirtualHost><br />
2283 <VirtualHost *:80><br />
2284 ServerName namebased-c.example.com <br />
2285 </VirtualHost><br />
2287 <VirtualHost *:80><br />
2288 ServerName namebased-d.example.com <br />
2289 </VirtualHost><br />
2294 <p>IPv6 addresses must be enclosed in square brackets, as shown
2295 in the following example:</p>
2298 NameVirtualHost [2001:db8::a00:20ff:fea7:ccea]:8080
2301 <note><title>Argument to <directive type="section">VirtualHost</directive>
2303 <p>Note that the argument to the <directive
2304 type="section">VirtualHost</directive> directive must
2305 exactly match the argument to the <directive
2306 >NameVirtualHost</directive> directive.</p>
2309 NameVirtualHost 192.0.2.2:80<br />
2310 <VirtualHost 192.0.2.2:80><br />
2312 </VirtualHost><br />
2317 <seealso><a href="../vhosts/">Virtual Hosts
2318 documentation</a></seealso>
2320 </directivesynopsis>
2323 <name>Options</name>
2324 <description>Configures what features are available in a particular
2325 directory</description>
2327 [+|-]<var>option</var> [[+|-]<var>option</var>] ...</syntax>
2328 <default>Options All</default>
2329 <contextlist><context>server config</context><context>virtual host</context>
2330 <context>directory</context><context>.htaccess</context>
2332 <override>Options</override>
2335 <p>The <directive>Options</directive> directive controls which
2336 server features are available in a particular directory.</p>
2338 <p><var>option</var> can be set to <code>None</code>, in which
2339 case none of the extra features are enabled, or one or more of
2343 <dt><code>All</code></dt>
2345 <dd>All options except for <code>MultiViews</code>. This is the default
2348 <dt><code>ExecCGI</code></dt>
2351 Execution of CGI scripts using <module>mod_cgi</module>
2354 <dt><code>FollowSymLinks</code></dt>
2358 The server will follow symbolic links in this directory.
2360 <p>Even though the server follows the symlink it does <em>not</em>
2361 change the pathname used to match against <directive type="section"
2362 module="core">Directory</directive> sections.</p>
2363 <p>Note also, that this option <strong>gets ignored</strong> if set
2364 inside a <directive type="section" module="core">Location</directive>
2366 <p>Omitting this option should not be considered a security restriction,
2367 since symlink testing is subject to race conditions that make it
2371 <dt><code>Includes</code></dt>
2374 Server-side includes provided by <module>mod_include</module>
2377 <dt><code>IncludesNOEXEC</code></dt>
2381 Server-side includes are permitted, but the <code>#exec
2382 cmd</code> and <code>#exec cgi</code> are disabled. It is still
2383 possible to <code>#include virtual</code> CGI scripts from
2384 <directive module="mod_alias">ScriptAlias</directive>ed
2387 <dt><code>Indexes</code></dt>
2390 If a URL which maps to a directory is requested, and there
2391 is no <directive module="mod_dir">DirectoryIndex</directive>
2392 (<em>e.g.</em>, <code>index.html</code>) in that directory, then
2393 <module>mod_autoindex</module> will return a formatted listing
2394 of the directory.</dd>
2396 <dt><code>MultiViews</code></dt>
2399 <a href="../content-negotiation.html">Content negotiated</a>
2400 "MultiViews" are allowed using
2401 <module>mod_negotiation</module>.</dd>
2403 <dt><code>SymLinksIfOwnerMatch</code></dt>
2405 <dd>The server will only follow symbolic links for which the
2406 target file or directory is owned by the same user id as the
2409 <note><title>Note</title> <p>This option gets ignored if
2410 set inside a <directive module="core"
2411 type="section">Location</directive> section.</p>
2412 <p>This option should not be considered a security restriction,
2413 since symlink testing is subject to race conditions that make it
2414 circumventable.</p></note>
2418 <p>Normally, if multiple <directive>Options</directive> could
2419 apply to a directory, then the most specific one is used and
2420 others are ignored; the options are not merged. (See <a
2421 href="../sections.html#mergin">how sections are merged</a>.)
2422 However if <em>all</em> the options on the
2423 <directive>Options</directive> directive are preceded by a
2424 <code>+</code> or <code>-</code> symbol, the options are
2425 merged. Any options preceded by a <code>+</code> are added to the
2426 options currently in force, and any options preceded by a
2427 <code>-</code> are removed from the options currently in
2430 <note type="warning"><title>Warning</title>
2431 <p>Mixing <directive>Options</directive> with a <code>+</code> or
2432 <code>-</code> with those without is not valid syntax, and is likely
2433 to cause unexpected results.</p>
2436 <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>
2439 <Directory /web/docs><br />
2441 Options Indexes FollowSymLinks<br />
2443 </Directory><br />
2445 <Directory /web/docs/spec><br />
2447 Options Includes<br />
2452 <p>then only <code>Includes</code> will be set for the
2453 <code>/web/docs/spec</code> directory. However if the second
2454 <directive>Options</directive> directive uses the <code>+</code> and
2455 <code>-</code> symbols:</p>
2458 <Directory /web/docs><br />
2460 Options Indexes FollowSymLinks<br />
2462 </Directory><br />
2464 <Directory /web/docs/spec><br />
2466 Options +Includes -Indexes<br />
2471 <p>then the options <code>FollowSymLinks</code> and
2472 <code>Includes</code> are set for the <code>/web/docs/spec</code>
2475 <note><title>Note</title>
2476 <p>Using <code>-IncludesNOEXEC</code> or
2477 <code>-Includes</code> disables server-side includes completely
2478 regardless of the previous setting.</p>
2481 <p>The default in the absence of any other settings is
2482 <code>All</code>.</p>
2484 </directivesynopsis>
2487 <name>RLimitCPU</name>
2488 <description>Limits the CPU consumption of processes launched
2489 by Apache children</description>
2490 <syntax>RLimitCPU <var>seconds</var>|max [<var>seconds</var>|max]</syntax>
2491 <default>Unset; uses operating system defaults</default>
2492 <contextlist><context>server config</context><context>virtual host</context>
2493 <context>directory</context><context>.htaccess</context></contextlist>
2494 <override>All</override>
2497 <p>Takes 1 or 2 parameters. The first parameter sets the soft
2498 resource limit for all processes and the second parameter sets
2499 the maximum resource limit. Either parameter can be a number,
2500 or <code>max</code> to indicate to the server that the limit should
2501 be set to the maximum allowed by the operating system
2502 configuration. Raising the maximum resource limit requires that
2503 the server is running as <code>root</code>, or in the initial startup
2506 <p>This applies to processes forked off from Apache children
2507 servicing requests, not the Apache children themselves. This
2508 includes CGI scripts and SSI exec commands, but not any
2509 processes forked off from the Apache parent such as piped
2512 <p>CPU resource limits are expressed in seconds per
2515 <seealso><directive module="core">RLimitMEM</directive></seealso>
2516 <seealso><directive module="core">RLimitNPROC</directive></seealso>
2517 </directivesynopsis>
2520 <name>RLimitMEM</name>
2521 <description>Limits the memory consumption of processes launched
2522 by Apache children</description>
2523 <syntax>RLimitMEM <var>bytes</var>|max [<var>bytes</var>|max]</syntax>
2524 <default>Unset; uses operating system defaults</default>
2525 <contextlist><context>server config</context><context>virtual host</context>
2526 <context>directory</context><context>.htaccess</context></contextlist>
2527 <override>All</override>
2530 <p>Takes 1 or 2 parameters. The first parameter sets the soft
2531 resource limit for all processes and the second parameter sets
2532 the maximum resource limit. Either parameter can be a number,
2533 or <code>max</code> to indicate to the server that the limit should
2534 be set to the maximum allowed by the operating system
2535 configuration. Raising the maximum resource limit requires that
2536 the server is running as <code>root</code>, or in the initial startup
2539 <p>This applies to processes forked off from Apache children
2540 servicing requests, not the Apache children themselves. This
2541 includes CGI scripts and SSI exec commands, but not any
2542 processes forked off from the Apache parent such as piped
2545 <p>Memory resource limits are expressed in bytes per
2548 <seealso><directive module="core">RLimitCPU</directive></seealso>
2549 <seealso><directive module="core">RLimitNPROC</directive></seealso>
2550 </directivesynopsis>
2553 <name>RLimitNPROC</name>
2554 <description>Limits the number of processes that can be launched by
2555 processes launched by Apache children</description>
2556 <syntax>RLimitNPROC <var>number</var>|max [<var>number</var>|max]</syntax>
2557 <default>Unset; uses operating system defaults</default>
2558 <contextlist><context>server config</context><context>virtual host</context>
2559 <context>directory</context><context>.htaccess</context></contextlist>
2560 <override>All</override>
2563 <p>Takes 1 or 2 parameters. The first parameter sets the soft
2564 resource limit for all processes and the second parameter sets
2565 the maximum resource limit. Either parameter can be a number,
2566 or <code>max</code> to indicate to the server that the limit
2567 should be set to the maximum allowed by the operating system
2568 configuration. Raising the maximum resource limit requires that
2569 the server is running as <code>root</code>, or in the initial startup
2572 <p>This applies to processes forked off from Apache children
2573 servicing requests, not the Apache children themselves. This
2574 includes CGI scripts and SSI exec commands, but not any
2575 processes forked off from the Apache parent such as piped
2578 <p>Process limits control the number of processes per user.</p>
2580 <note><title>Note</title>
2581 <p>If CGI processes are <strong>not</strong> running
2582 under user ids other than the web server user id, this directive
2583 will limit the number of processes that the server itself can
2584 create. Evidence of this situation will be indicated by
2585 <strong><code>cannot fork</code></strong> messages in the
2586 <code>error_log</code>.</p>
2589 <seealso><directive module="core">RLimitMEM</directive></seealso>
2590 <seealso><directive module="core">RLimitCPU</directive></seealso>
2591 </directivesynopsis>
2594 <name>ScriptInterpreterSource</name>
2595 <description>Technique for locating the interpreter for CGI
2596 scripts</description>
2597 <syntax>ScriptInterpreterSource Registry|Registry-Strict|Script</syntax>
2598 <default>ScriptInterpreterSource Script</default>
2599 <contextlist><context>server config</context><context>virtual host</context>
2600 <context>directory</context><context>.htaccess</context></contextlist>
2601 <override>FileInfo</override>
2602 <compatibility>Win32 only;
2603 option <code>Registry-Strict</code> is available in Apache 2.0 and
2604 later</compatibility>
2607 <p>This directive is used to control how Apache finds the
2608 interpreter used to run CGI scripts. The default setting is
2609 <code>Script</code>. This causes Apache to use the interpreter pointed to
2610 by the shebang line (first line, starting with <code>#!</code>) in the
2611 script. On Win32 systems this line usually looks like:</p>
2614 #!C:/Perl/bin/perl.exe
2617 <p>or, if <code>perl</code> is in the <code>PATH</code>, simply:</p>
2623 <p>Setting <code>ScriptInterpreterSource Registry</code> will
2624 cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
2625 searched using the script file extension (e.g., <code>.pl</code>) as a
2626 search key. The command defined by the registry subkey
2627 <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
2628 <code>Shell\Open\Command</code> is used to open the script file. If the
2629 registry keys cannot be found, Apache falls back to the behavior of the
2630 <code>Script</code> option.</p>
2632 <note type="warning"><title>Security</title>
2633 <p>Be careful when using <code>ScriptInterpreterSource
2634 Registry</code> with <directive
2635 module="mod_alias">ScriptAlias</directive>'ed directories, because
2636 Apache will try to execute <strong>every</strong> file within this
2637 directory. The <code>Registry</code> setting may cause undesired
2638 program calls on files which are typically not executed. For
2639 example, the default open command on <code>.htm</code> files on
2640 most Windows systems will execute Microsoft Internet Explorer, so
2641 any HTTP request for an <code>.htm</code> file existing within the
2642 script directory would start the browser in the background on the
2643 server. This is a good way to crash your system within a minute or
2647 <p>The option <code>Registry-Strict</code> which is new in Apache
2648 2.0 does the same thing as <code>Registry</code> but uses only the
2649 subkey <code>Shell\ExecCGI\Command</code>. The
2650 <code>ExecCGI</code> key is not a common one. It must be
2651 configured manually in the windows registry and hence prevents
2652 accidental program calls on your system.</p>
2654 </directivesynopsis>
2657 <name>ServerAdmin</name>
2658 <description>Email address that the server includes in error
2659 messages sent to the client</description>
2660 <syntax>ServerAdmin <var>email-address</var>|<var>URL</var></syntax>
2661 <contextlist><context>server config</context><context>virtual host</context>
2665 <p>The <directive>ServerAdmin</directive> sets the contact address
2666 that the server includes in any error messages it returns to the
2667 client. If the <code>httpd</code> doesn't recognize the supplied argument
2669 assumes, that it's an <var>email-address</var> and prepends it with
2670 <code>mailto:</code> in hyperlink targets. However, it's recommended to
2671 actually use an email address, since there are a lot of CGI scripts that
2672 make that assumption. If you want to use an URL, it should point to another
2673 server under your control. Otherwise users may not be able to contact you in
2676 <p>It may be worth setting up a dedicated address for this, e.g.</p>
2679 ServerAdmin www-admin@foo.example.com
2681 <p>as users do not always mention that they are talking about the
2684 </directivesynopsis>
2687 <name>ServerAlias</name>
2688 <description>Alternate names for a host used when matching requests
2689 to name-virtual hosts</description>
2690 <syntax>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</syntax>
2691 <contextlist><context>virtual host</context></contextlist>
2694 <p>The <directive>ServerAlias</directive> directive sets the
2695 alternate names for a host, for use with <a
2696 href="../vhosts/name-based.html">name-based virtual hosts</a>. The
2697 <directive>ServerAlias</directive> may include wildcards, if appropriate.</p>
2700 <VirtualHost *:80><br />
2701 ServerName server.domain.com<br />
2702 ServerAlias server server2.domain.com server2<br />
2703 ServerAlias *.example.com<br />
2705 </VirtualHost>
2708 <seealso><a href="../vhosts/">Apache Virtual Host documentation</a></seealso>
2709 </directivesynopsis>
2712 <name>ServerName</name>
2713 <description>Hostname and port that the server uses to identify
2714 itself</description>
2715 <syntax>ServerName [<var>scheme</var>://]<var>fully-qualified-domain-name</var>[:<var>port</var>]</syntax>
2716 <contextlist><context>server config</context><context>virtual host</context>
2718 <compatibility>In version 2.0, this
2719 directive supersedes the functionality of the <directive>Port</directive>
2720 directive from version 1.3.</compatibility>
2723 <p>The <directive>ServerName</directive> directive sets the
2724 request scheme, hostname and
2725 port that the server uses to identify itself. This is used when
2726 creating redirection URLs. For example, if the name of the
2727 machine hosting the web server is <code>simple.example.com</code>,
2728 but the machine also has the DNS alias <code>www.example.com</code>
2729 and you wish the web server to be so identified, the following
2730 directive should be used:</p>
2733 ServerName www.example.com:80
2736 <p>If no <directive>ServerName</directive> is specified, then the
2737 server attempts to deduce the hostname by performing a reverse
2738 lookup on the IP address. If no port is specified in the
2739 <directive>ServerName</directive>, then the server will use the
2740 port from the incoming request. For optimal reliability and
2741 predictability, you should specify an explicit hostname and port
2742 using the <directive>ServerName</directive> directive.</p>
2744 <p>If you are using <a
2745 href="../vhosts/name-based.html">name-based virtual hosts</a>,
2746 the <directive>ServerName</directive> inside a
2747 <directive type="section" module="core">VirtualHost</directive>
2748 section specifies what hostname must appear in the request's
2749 <code>Host:</code> header to match this virtual host.</p>
2752 <p>Sometimes, the server runs behind a device that processes SSL,
2753 such as a reverse proxy, load balancer or SSL offload
2754 appliance. When this is the case, specify the
2755 <code>https://</code> scheme and the port number to which the
2756 clients connect in the <directive>ServerName</directive> directive
2757 to make sure that the server generates the correct
2758 self-referential URLs.
2761 <p>See the description of the
2762 <directive module="core">UseCanonicalName</directive> and
2763 <directive module="core">UseCanonicalPhysicalPort</directive> directives for
2764 settings which determine whether self-referential URLs (e.g., by the
2765 <module>mod_dir</module> module) will refer to the
2766 specified port, or to the port number given in the client's request.
2771 <seealso><a href="../dns-caveats.html">Issues Regarding DNS and
2772 Apache</a></seealso>
2773 <seealso><a href="../vhosts/">Apache virtual host
2774 documentation</a></seealso>
2775 <seealso><directive module="core">UseCanonicalName</directive></seealso>
2776 <seealso><directive module="core">UseCanonicalPhysicalPort</directive></seealso>
2777 <seealso><directive module="core">NameVirtualHost</directive></seealso>
2778 <seealso><directive module="core">ServerAlias</directive></seealso>
2779 </directivesynopsis>
2782 <name>ServerPath</name>
2783 <description>Legacy URL pathname for a name-based virtual host that
2784 is accessed by an incompatible browser</description>
2785 <syntax>ServerPath <var>URL-path</var></syntax>
2786 <contextlist><context>virtual host</context></contextlist>
2789 <p>The <directive>ServerPath</directive> directive sets the legacy
2790 URL pathname for a host, for use with <a
2791 href="../vhosts/">name-based virtual hosts</a>.</p>
2793 <seealso><a href="../vhosts/">Apache Virtual Host documentation</a></seealso>
2794 </directivesynopsis>
2797 <name>ServerRoot</name>
2798 <description>Base directory for the server installation</description>
2799 <syntax>ServerRoot <var>directory-path</var></syntax>
2800 <default>ServerRoot /usr/local/apache</default>
2801 <contextlist><context>server config</context></contextlist>
2804 <p>The <directive>ServerRoot</directive> directive sets the
2805 directory in which the server lives. Typically it will contain the
2806 subdirectories <code>conf/</code> and <code>logs/</code>. Relative
2807 paths in other configuration directives (such as <directive
2808 module="core">Include</directive> or <directive
2809 module="mod_so">LoadModule</directive>, for example) are taken as
2810 relative to this directory.</p>
2812 <example><title>Example</title>
2813 ServerRoot /home/httpd
2817 <seealso><a href="../invoking.html">the <code>-d</code>
2818 option to <code>httpd</code></a></seealso>
2819 <seealso><a href="../misc/security_tips.html#serverroot">the
2820 security tips</a> for information on how to properly set
2821 permissions on the <directive>ServerRoot</directive></seealso>
2822 </directivesynopsis>
2825 <name>ServerSignature</name>
2826 <description>Configures the footer on server-generated documents</description>
2827 <syntax>ServerSignature On|Off|EMail</syntax>
2828 <default>ServerSignature Off</default>
2829 <contextlist><context>server config</context><context>virtual host</context>
2830 <context>directory</context><context>.htaccess</context>
2832 <override>All</override>
2835 <p>The <directive>ServerSignature</directive> directive allows the
2836 configuration of a trailing footer line under server-generated
2837 documents (error messages, <module>mod_proxy</module> ftp directory
2838 listings, <module>mod_info</module> output, ...). The reason why you
2839 would want to enable such a footer line is that in a chain of proxies,
2840 the user often has no possibility to tell which of the chained servers
2841 actually produced a returned error message.</p>
2843 <p>The <code>Off</code>
2844 setting, which is the default, suppresses the footer line (and is
2845 therefore compatible with the behavior of Apache-1.2 and
2846 below). The <code>On</code> setting simply adds a line with the
2847 server version number and <directive
2848 module="core">ServerName</directive> of the serving virtual host,
2849 and the <code>EMail</code> setting additionally creates a
2850 "mailto:" reference to the <directive
2851 module="core">ServerAdmin</directive> of the referenced
2854 <p>After version 2.0.44, the details of the server version number
2855 presented are controlled by the <directive
2856 module="core">ServerTokens</directive> directive.</p>
2858 <seealso><directive module="core">ServerTokens</directive></seealso>
2859 </directivesynopsis>
2862 <name>ServerTokens</name>
2863 <description>Configures the <code>Server</code> HTTP response
2864 header</description>
2865 <syntax>ServerTokens Major|Minor|Min[imal]|Prod[uctOnly]|OS|Full</syntax>
2866 <default>ServerTokens Full</default>
2867 <contextlist><context>server config</context></contextlist>
2870 <p>This directive controls whether <code>Server</code> response
2871 header field which is sent back to clients includes a
2872 description of the generic OS-type of the server as well as
2873 information about compiled-in modules.</p>
2876 <dt><code>ServerTokens Prod[uctOnly]</code></dt>
2878 <dd>Server sends (<em>e.g.</em>): <code>Server:
2881 <dt><code>ServerTokens Major</code></dt>
2883 <dd>Server sends (<em>e.g.</em>): <code>Server:
2884 Apache/2</code></dd>
2886 <dt><code>ServerTokens Minor</code></dt>
2888 <dd>Server sends (<em>e.g.</em>): <code>Server:
2889 Apache/2.0</code></dd>
2891 <dt><code>ServerTokens Min[imal]</code></dt>
2893 <dd>Server sends (<em>e.g.</em>): <code>Server:
2894 Apache/2.0.41</code></dd>
2896 <dt><code>ServerTokens OS</code></dt>
2898 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.0.41
2901 <dt><code>ServerTokens Full</code> (or not specified)</dt>
2903 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.0.41
2904 (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
2907 <p>This setting applies to the entire server, and cannot be
2908 enabled or disabled on a virtualhost-by-virtualhost basis.</p>
2910 <p>After version 2.0.44, this directive also controls the
2911 information presented by the <directive
2912 module="core">ServerSignature</directive> directive.</p>
2914 <seealso><directive module="core">ServerSignature</directive></seealso>
2915 </directivesynopsis>
2918 <name>SetHandler</name>
2919 <description>Forces all matching files to be processed by a
2920 handler</description>
2921 <syntax>SetHandler <var>handler-name</var>|None</syntax>
2922 <contextlist><context>server config</context><context>virtual host</context>
2923 <context>directory</context><context>.htaccess</context>
2925 <override>FileInfo</override>
2926 <compatibility>Moved into the core in Apache 2.0</compatibility>
2929 <p>When placed into an <code>.htaccess</code> file or a
2930 <directive type="section" module="core">Directory</directive> or
2931 <directive type="section" module="core">Location</directive>
2932 section, this directive forces all matching files to be parsed
2933 through the <a href="../handler.html">handler</a> given by
2934 <var>handler-name</var>. For example, if you had a directory you
2935 wanted to be parsed entirely as imagemap rule files, regardless
2936 of extension, you might put the following into an
2937 <code>.htaccess</code> file in that directory:</p>
2940 SetHandler imap-file
2943 <p>Another example: if you wanted to have the server display a
2944 status report whenever a URL of
2945 <code>http://servername/status</code> was called, you might put
2946 the following into <code>httpd.conf</code>:</p>
2949 <Location /status><br />
2951 SetHandler server-status<br />
2956 <p>You can override an earlier defined <directive>SetHandler</directive>
2957 directive by using the value <code>None</code>.</p>
2958 <p><strong>Note:</strong> because SetHandler overrides default handlers,
2959 normal behaviour such as handling of URLs ending in a slash (/) as
2960 directories or index files is suppressed.</p>
2963 <seealso><directive module="mod_mime">AddHandler</directive></seealso>
2965 </directivesynopsis>
2968 <name>SetInputFilter</name>
2969 <description>Sets the filters that will process client requests and POST
2971 <syntax>SetInputFilter <var>filter</var>[;<var>filter</var>...]</syntax>
2972 <contextlist><context>server config</context><context>virtual host</context>
2973 <context>directory</context><context>.htaccess</context>
2975 <override>FileInfo</override>
2978 <p>The <directive>SetInputFilter</directive> directive sets the
2979 filter or filters which will process client requests and POST
2980 input when they are received by the server. This is in addition to
2981 any filters defined elsewhere, including the
2982 <directive module="mod_mime">AddInputFilter</directive>
2985 <p>If more than one filter is specified, they must be separated
2986 by semicolons in the order in which they should process the
2989 <seealso><a href="../filter.html">Filters</a> documentation</seealso>
2990 </directivesynopsis>
2993 <name>SetOutputFilter</name>
2994 <description>Sets the filters that will process responses from the
2995 server</description>
2996 <syntax>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</syntax>
2997 <contextlist><context>server config</context><context>virtual host</context>
2998 <context>directory</context><context>.htaccess</context>
3000 <override>FileInfo</override>
3003 <p>The <directive>SetOutputFilter</directive> directive sets the filters
3004 which will process responses from the server before they are
3005 sent to the client. This is in addition to any filters defined
3006 elsewhere, including the
3007 <directive module="mod_mime">AddOutputFilter</directive>
3010 <p>For example, the following configuration will process all files
3011 in the <code>/www/data/</code> directory for server-side
3015 <Directory /www/data/><br />
3017 SetOutputFilter INCLUDES<br />
3022 <p>If more than one filter is specified, they must be separated
3023 by semicolons in the order in which they should process the
3026 <seealso><a href="../filter.html">Filters</a> documentation</seealso>
3027 </directivesynopsis>
3030 <name>TimeOut</name>
3031 <description>Amount of time the server will wait for
3032 certain events before failing a request</description>
3033 <syntax>TimeOut <var>seconds</var></syntax>
3034 <default>TimeOut 300</default>
3035 <contextlist><context>server config</context><context>virtual host</context></contextlist>
3038 <p>The <directive>TimeOut</directive> directive defines the length
3039 of time Apache will wait for I/O in various circumstances:</p>
3042 <li>When reading data from the client, the length of time to
3043 wait for a TCP packet to arrive if the read buffer is
3046 <li>When writing data to the client, the length of time to wait
3047 for an acknowledgement of a packet if the send buffer is
3050 <li>In <module>mod_cgi</module>, the length of time to wait for
3051 output from a CGI script.</li>
3053 <li>In <module>mod_ext_filter</module>, the length of time to
3054 wait for output from a filtering process.</li>
3056 <li>In <module>mod_proxy</module>, the default timeout value if
3057 <directive module="mod_proxy">ProxyTimeout</directive> is not
3062 </directivesynopsis>
3065 <name>TraceEnable</name>
3066 <description>Determines the behaviour on <code>TRACE</code>
3067 requests</description>
3068 <syntax>TraceEnable <var>[on|off|extended]</var></syntax>
3069 <default>TraceEnable on</default>
3070 <contextlist><context>server config</context></contextlist>
3071 <compatibility>Available in Apache 1.3.34, 2.0.55 and later</compatibility>
3074 <p>This directive overrides the behavior of <code>TRACE</code> for both
3075 the core server and <module>mod_proxy</module>. The default
3076 <code>TraceEnable on</code> permits <code>TRACE</code> requests per
3077 RFC 2616, which disallows any request body to accompany the request.
3078 <code>TraceEnable off</code> causes the core server and
3079 <module>mod_proxy</module> to return a <code>405</code> (Method not
3080 allowed) error to the client.</p>
3082 <p>Finally, for testing and diagnostic purposes only, request
3083 bodies may be allowed using the non-compliant <code>TraceEnable
3084 extended</code> directive. The core (as an origin server) will
3085 restrict the request body to 64k (plus 8k for chunk headers if
3086 <code>Transfer-Encoding: chunked</code> is used). The core will
3087 reflect the full headers and all chunk headers with the response
3088 body. As a proxy server, the request body is not restricted to 64k.</p>
3090 </directivesynopsis>
3093 <name>UseCanonicalName</name>
3094 <description>Configures how the server determines its own name and
3096 <syntax>UseCanonicalName On|Off|DNS</syntax>
3097 <default>UseCanonicalName Off</default>
3098 <contextlist><context>server config</context><context>virtual host</context>
3099 <context>directory</context></contextlist>
3102 <p>In many situations Apache must construct a <em>self-referential</em>
3103 URL -- that is, a URL that refers back to the same server. With
3104 <code>UseCanonicalName On</code> Apache will use the hostname and port
3105 specified in the <directive module="core">ServerName</directive>
3106 directive to construct the canonical name for the server. This name
3107 is used in all self-referential URLs, and for the values of
3108 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>
3110 <p>With <code>UseCanonicalName Off</code> Apache will form
3111 self-referential URLs using the hostname and port supplied by
3112 the client if any are supplied (otherwise it will use the
3113 canonical name, as defined above). These values are the same
3114 that are used to implement <a
3115 href="../vhosts/name-based.html">name based virtual hosts</a>,
3116 and are available with the same clients. The CGI variables
3117 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
3118 constructed from the client supplied values as well.</p>
3120 <p>An example where this may be useful is on an intranet server
3121 where you have users connecting to the machine using short
3122 names such as <code>www</code>. You'll notice that if the users
3123 type a shortname, and a URL which is a directory, such as
3124 <code>http://www/splat</code>, <em>without the trailing
3125 slash</em> then Apache will redirect them to
3126 <code>http://www.domain.com/splat/</code>. If you have
3127 authentication enabled, this will cause the user to have to
3128 authenticate twice (once for <code>www</code> and once again
3129 for <code>www.domain.com</code> -- see <a
3130 href="http://httpd.apache.org/docs/misc/FAQ.html#prompted-twice">the
3131 FAQ on this subject for more information</a>). But if
3132 <directive>UseCanonicalName</directive> is set <code>Off</code>, then
3133 Apache will redirect to <code>http://www/splat/</code>.</p>
3135 <p>There is a third option, <code>UseCanonicalName DNS</code>,
3136 which is intended for use with mass IP-based virtual hosting to
3137 support ancient clients that do not provide a
3138 <code>Host:</code> header. With this option Apache does a
3139 reverse DNS lookup on the server IP address that the client
3140 connected to in order to work out self-referential URLs.</p>
3142 <note type="warning"><title>Warning</title>
3143 <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>
3144 they may be broken by this option. The client is essentially free
3145 to give whatever value they want as a hostname. But if the CGI is
3146 only using <code>SERVER_NAME</code> to construct self-referential URLs
3147 then it should be just fine.</p>
3150 <seealso><directive module="core">UseCanonicalPhysicalPort</directive></seealso>
3151 <seealso><directive module="core">ServerName</directive></seealso>
3152 <seealso><directive module="mpm_common">Listen</directive></seealso>
3153 </directivesynopsis>
3156 <name>UseCanonicalPhysicalPort</name>
3157 <description>Configures how the server determines its own name and
3159 <syntax>UseCanonicalPhysicalPort On|Off</syntax>
3160 <default>UseCanonicalPhysicalPort Off</default>
3161 <contextlist><context>server config</context><context>virtual host</context>
3162 <context>directory</context></contextlist>
3165 <p>In many situations Apache must construct a <em>self-referential</em>
3166 URL -- that is, a URL that refers back to the same server. With
3167 <code>UseCanonicalPhysicalPort On</code> Apache will, when
3168 constructing the canonical port for the server to honor
3169 the <directive module="core">UseCanonicalName</directive> directive,
3170 provide the actual physical port number being used by this request
3171 as a potential port. With <code>UseCanonicalPhysicalPort Off</code>
3172 Apache will not ever use the actual physical port number, instead
3173 relying on all configured information to construct a valid port number.</p>
3175 <note><title>Note</title>
3176 <p>The ordering of when the physical port is used is as follows:<br /><br />
3177 <code>UseCanonicalName On</code></p>
3179 <li>Port provided in <code>Servername</code></li>
3180 <li>Physical port</li>
3181 <li>Default port</li>
3183 <code>UseCanonicalName Off | DNS</code>
3185 <li>Parsed port from <code>Host:</code> header</li>
3186 <li>Physical port</li>
3187 <li>Port provided in <code>Servername</code></li>
3188 <li>Default port</li>
3191 <p>With <code>UseCanonicalPhysicalPort Off</code>, the
3192 physical ports are removed from the ordering.</p>
3196 <seealso><directive module="core">UseCanonicalName</directive></seealso>
3197 <seealso><directive module="core">ServerName</directive></seealso>
3198 <seealso><directive module="mpm_common">Listen</directive></seealso>
3199 </directivesynopsis>
3201 <directivesynopsis type="section">
3202 <name>VirtualHost</name>
3203 <description>Contains directives that apply only to a specific
3204 hostname or IP address</description>
3205 <syntax><VirtualHost
3206 <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
3207 ...> ... </VirtualHost></syntax>
3208 <contextlist><context>server config</context></contextlist>
3211 <p><directive type="section">VirtualHost</directive> and
3212 <code></VirtualHost></code> are used to enclose a group of
3213 directives that will apply only to a particular virtual host. Any
3214 directive that is allowed in a virtual host context may be
3215 used. When the server receives a request for a document on a
3216 particular virtual host, it uses the configuration directives
3217 enclosed in the <directive type="section">VirtualHost</directive>
3218 section. <var>Addr</var> can be:</p>
3221 <li>The IP address of the virtual host;</li>
3223 <li>A fully qualified domain name for the IP address of the
3224 virtual host (not recommended);</li>
3226 <li>The character <code>*</code>, which is used only in combination with
3227 <code>NameVirtualHost *</code> to match all IP addresses; or</li>
3229 <li>The string <code>_default_</code>, which is used only
3230 with IP virtual hosting to catch unmatched IP addresses.</li>
3233 <example><title>Example</title>
3234 <VirtualHost 10.1.2.3><br />
3236 ServerAdmin webmaster@host.example.com<br />
3237 DocumentRoot /www/docs/host.example.com<br />
3238 ServerName host.example.com<br />
3239 ErrorLog logs/host.example.com-error_log<br />
3240 TransferLog logs/host.example.com-access_log<br />
3242 </VirtualHost>
3246 <p>IPv6 addresses must be specified in square brackets because
3247 the optional port number could not be determined otherwise. An
3248 IPv6 example is shown below:</p>
3251 <VirtualHost [2001:db8::a00:20ff:fea7:ccea]><br />
3253 ServerAdmin webmaster@host.example.com<br />
3254 DocumentRoot /www/docs/host.example.com<br />
3255 ServerName host.example.com<br />
3256 ErrorLog logs/host.example.com-error_log<br />
3257 TransferLog logs/host.example.com-access_log<br />
3259 </VirtualHost>
3262 <p>Each Virtual Host must correspond to a different IP address,
3263 different port number or a different host name for the server,
3264 in the former case the server machine must be configured to
3265 accept IP packets for multiple addresses. (If the machine does
3266 not have multiple network interfaces, then this can be
3267 accomplished with the <code>ifconfig alias</code> command -- if
3268 your OS supports it).</p>
3270 <note><title>Note</title>
3271 <p>The use of <directive type="section">VirtualHost</directive> does
3272 <strong>not</strong> affect what addresses Apache listens on. You
3273 may need to ensure that Apache is listening on the correct addresses
3274 using <directive module="mpm_common">Listen</directive>.</p>
3277 <p>When using IP-based virtual hosting, the special name
3278 <code>_default_</code> can be specified in
3279 which case this virtual host will match any IP address that is
3280 not explicitly listed in another virtual host. In the absence
3281 of any <code>_default_</code> virtual host the "main" server config,
3282 consisting of all those definitions outside any VirtualHost
3283 section, is used when no IP-match occurs.</p>
3285 <p>You can specify a <code>:port</code> to change the port that is
3286 matched. If unspecified then it defaults to the same port as the
3287 most recent <directive module="mpm_common">Listen</directive>
3288 statement of the main server. You may also specify <code>:*</code>
3289 to match all ports on that address. (This is recommended when used
3290 with <code>_default_</code>.)</p>
3292 <p>A <directive module="core">ServerName</directive> should be
3293 specified inside each <directive
3294 type="section">VirtualHost</directive> block. If it is absent, the
3295 <directive module="core">ServerName</directive> from the "main"
3296 server configuration will be inherited.</p>
3298 <note type="warning"><title>Security</title>
3299 <p>See the <a href="../misc/security_tips.html">security tips</a>
3300 document for details on why your security could be compromised if the
3301 directory where log files are stored is writable by anyone other
3302 than the user that starts the server.</p>
3305 <seealso><a href="../vhosts/">Apache Virtual Host documentation</a></seealso>
3306 <seealso><a href="../dns-caveats.html">Issues Regarding DNS and
3307 Apache</a></seealso>
3308 <seealso><a href="../bind.html">Setting
3309 which addresses and ports Apache uses</a></seealso>
3310 <seealso><a href="../sections.html">How <Directory>, <Location>
3311 and <Files> sections work</a> for an explanation of how these
3312 different sections are combined when a request is received</seealso>
3313 </directivesynopsis>