2 <!DOCTYPE modulesynopsis SYSTEM "../style/modulesynopsis.dtd">
3 <?xml-stylesheet type="text/xsl" href="../style/manual.en.xsl"?>
4 <!-- $LastChangedRevision$ -->
7 Copyright 2002-2005 The Apache Software Foundation or its licensors, as
10 Licensed under the Apache License, Version 2.0 (the "License");
11 you may not use this file except in compliance with the License.
12 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</compatibility>
38 <p>This directive enables operating system specific optimizations for a
39 listening socket by the Protocol type. The basic premise is for the
40 kernel to not send a socket to the server process until either data
41 is received or an entire HTTP Request is buffered. Only
42 <a href="http://www.freebsd.org/cgi/man.cgi?query=accept_filter&sektion=9">
43 FreeBSD's Accept Filters</a> and Linux's more primitive
44 <code>TCP_DEFER_ACCEPT</code> are currently supported.</p>
46 <p>The default values on FreeBSD are:</p>
48 AcceptFilter http httpready <br/>
49 AcceptFilter https dataready
52 <p>The <code>httpready</code> accept filter buffers entire HTTP requests at
53 the kernel level. Once an entire request is recieved, the kernel then
54 sends it to the server. See the
55 <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_http&sektion=9">
56 accf_http(9)</a> man page for more details. Since HTTPS requests are
57 encrypted only the <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_data&sektion=9">
58 accf_data(9)</a> filter is used.</p>
60 <p>The default values on Linux are:</p>
62 AcceptFilter http data <br/>
63 AcceptFilter https data
66 <p>Linux's <code>TCP_DEFER_ACCEPT</code> does not support buffering http
67 requests. Any value besides <code>none</code> will enable
68 <code>TCP_DEFER_ACCEPT</code> on that listener. For more details
70 <a href="http://homepages.cwi.nl/~aeb/linux/man2html/man7/tcp.7.html">
71 tcp(7)</a> man page.</p>
73 <p>Using <code>none</code> for an argument will disable any accept filters
74 for that protocol. This is useful for protocols that require a server
75 send data first, such as <code>nntp</code>:</p>
76 <example>AcceptFilter nttp none</example>
82 <name>AcceptPathInfo</name>
83 <description>Resources accept trailing pathname information</description>
84 <syntax>AcceptPathInfo On|Off|Default</syntax>
85 <default>AcceptPathInfo Default</default>
86 <contextlist><context>server config</context>
87 <context>virtual host</context><context>directory</context>
88 <context>.htaccess</context></contextlist>
89 <override>FileInfo</override>
90 <compatibility>Available in Apache 2.0.30 and later</compatibility>
94 <p>This directive controls whether requests that contain trailing
95 pathname information that follows an actual filename (or
96 non-existent file in an existing directory) will be accepted or
97 rejected. The trailing pathname information can be made
98 available to scripts in the <code>PATH_INFO</code> environment
101 <p>For example, assume the location <code>/test/</code> points to
102 a directory that contains only the single file
103 <code>here.html</code>. Then requests for
104 <code>/test/here.html/more</code> and
105 <code>/test/nothere.html/more</code> both collect
106 <code>/more</code> as <code>PATH_INFO</code>.</p>
108 <p>The three possible arguments for the
109 <directive>AcceptPathInfo</directive> directive are:</p>
111 <dt><code>Off</code></dt><dd>A request will only be accepted if it
112 maps to a literal path that exists. Therefore a request with
113 trailing pathname information after the true filename such as
114 <code>/test/here.html/more</code> in the above example will return
115 a 404 NOT FOUND error.</dd>
117 <dt><code>On</code></dt><dd>A request will be accepted if a
118 leading path component maps to a file that exists. The above
119 example <code>/test/here.html/more</code> will be accepted if
120 <code>/test/here.html</code> maps to a valid file.</dd>
122 <dt><code>Default</code></dt><dd>The treatment of requests with
123 trailing pathname information is determined by the <a
124 href="../handler.html">handler</a> responsible for the request.
125 The core handler for normal files defaults to rejecting
126 <code>PATH_INFO</code> requests. Handlers that serve scripts, such as <a
127 href="mod_cgi.html">cgi-script</a> and <a
128 href="mod_isapi.html">isapi-isa</a>, generally accept
129 <code>PATH_INFO</code> by default.</dd>
132 <p>The primary purpose of the <code>AcceptPathInfo</code>
133 directive is to allow you to override the handler's choice of
134 accepting or rejecting <code>PATH_INFO</code>. This override is required,
135 for example, when you use a <a href="../filter.html">filter</a>, such
136 as <a href="mod_include.html">INCLUDES</a>, to generate content
137 based on <code>PATH_INFO</code>. The core handler would usually reject
138 the request, so you can use the following configuration to enable
142 <Files "mypaths.shtml"><br />
144 Options +Includes<br />
145 SetOutputFilter INCLUDES<br />
146 AcceptPathInfo On<br />
155 <name>AccessFileName</name>
156 <description>Name of the distributed configuration file</description>
157 <syntax>AccessFileName <var>filename</var> [<var>filename</var>] ...</syntax>
158 <default>AccessFileName .htaccess</default>
159 <contextlist><context>server config</context><context>virtual host</context>
163 <p>While processing a request the server looks for
164 the first existing configuration file from this list of names in
165 every directory of the path to the document, if distributed
166 configuration files are <a href="#allowoverride">enabled for that
167 directory</a>. For example:</p>
173 <p>before returning the document
174 <code>/usr/local/web/index.html</code>, the server will read
175 <code>/.acl</code>, <code>/usr/.acl</code>,
176 <code>/usr/local/.acl</code> and <code>/usr/local/web/.acl</code>
177 for directives, unless they have been disabled with</p>
180 <Directory /><br />
182 AllowOverride None<br />
187 <seealso><directive module="core">AllowOverride</directive></seealso>
188 <seealso><a href="../configuring.html">Configuration Files</a></seealso>
189 <seealso><a href="../howto/htaccess.html">.htaccess Files</a></seealso>
193 <name>AddDefaultCharset</name>
194 <description>Default charset parameter to be added when a response
195 content-type is <code>text/plain</code> or <code>text/html</code></description>
196 <syntax>AddDefaultCharset On|Off|<var>charset</var></syntax>
197 <default>AddDefaultCharset Off</default>
198 <contextlist><context>server config</context>
199 <context>virtual host</context><context>directory</context>
200 <context>.htaccess</context></contextlist>
201 <override>FileInfo</override>
204 <p>This directive specifies a default value for the media type
205 charset parameter (the name of a character encoding) to be added
206 to a response if and only if the response's content-type is either
207 <code>text/plain</code> or <code>text/html</code>. This should override
208 any charset specified in the body of the response via a <code>META</code>
209 element, though the exact behavior is often dependent on the user's client
210 configuration. A setting of <code>AddDefaultCharset Off</code>
211 disables this functionality. <code>AddDefaultCharset On</code> enables
212 a default charset of <code>iso-8859-1</code>. Any other value is assumed
213 to be the <var>charset</var> to be used, which should be one of the
214 <a href="http://www.iana.org/assignments/character-sets">IANA registered
215 charset values</a> for use in MIME media types.
219 AddDefaultCharset utf-8
222 <p><directive>AddDefaultCharset</directive> should only be used when all
223 of the text resources to which it applies are known to be in that
224 character encoding and it is too inconvenient to label their charset
225 individually. One such example is to add the charset parameter
226 to resources containing generated content, such as legacy CGI
227 scripts, that might be vulnerable to cross-site scripting attacks
228 due to user-provided data being included in the output. Note, however,
229 that a better solution is to just fix (or delete) those scripts, since
230 setting a default charset does not protect users that have enabled
231 the "auto-detect character encoding" feature on their browser.</p>
233 <seealso><directive module="mod_mime">AddCharset</directive></seealso>
237 <name>AddOutputFilterByType</name>
238 <description>assigns an output filter to a particular MIME-type</description>
239 <syntax>AddOutputFilterByType <var>filter</var>[;<var>filter</var>...]
240 <var>MIME-type</var> [<var>MIME-type</var>] ...</syntax>
241 <contextlist><context>server config</context>
242 <context>virtual host</context><context>directory</context>
243 <context>.htaccess</context></contextlist>
244 <override>FileInfo</override>
245 <compatibility>Available in Apache 2.0.33 and later; deprecated in Apache 2.1 and later</compatibility>
248 <p>This directive activates a particular output <a
249 href="../filter.html">filter</a> for a request depending on the
250 response <glossary>MIME-type</glossary>. Because of certain
251 problems discussed below, this directive is deprecated. The same
252 functionality is available using <module>mod_filter</module>.</p>
254 <p>The following example uses the <code>DEFLATE</code> filter, which
255 is provided by <module>mod_deflate</module>. It will compress all
256 output (either static or dynamic) which is labeled as
257 <code>text/html</code> or <code>text/plain</code> before it is sent
261 AddOutputFilterByType DEFLATE text/html text/plain
264 <p>If you want the content to be processed by more than one filter, their
265 names have to be separated by semicolons. It's also possible to use one
266 <directive>AddOutputFilterByType</directive> directive for each of
269 <p>The configuration below causes all script output labeled as
270 <code>text/html</code> to be processed at first by the
271 <code>INCLUDES</code> filter and then by the <code>DEFLATE</code>
275 <Location /cgi-bin/><br />
277 Options Includes<br />
278 AddOutputFilterByType INCLUDES;DEFLATE text/html<br />
283 <note type="warning"><title>Note</title>
284 <p>Enabling filters with <directive>AddOutputFilterByType</directive>
285 may fail partially or completely in some cases. For example, no
286 filters are applied if the <glossary>MIME-type</glossary> could not be determined and falls
287 back to the <directive module="core">DefaultType</directive> setting,
288 even if the <directive module="core">DefaultType</directive> is the
291 <p>However, if you want to make sure, that the filters will be
292 applied, assign the content type to a resource explicitly, for
293 example with <directive module="mod_mime">AddType</directive> or
294 <directive module="core">ForceType</directive>. Setting the
295 content type within a (non-nph) CGI script is also safe.</p>
297 <p>The by-type output filters are never applied on proxy requests.</p>
301 <seealso><directive module="mod_mime">AddOutputFilter</directive></seealso>
302 <seealso><directive module="core">SetOutputFilter</directive></seealso>
303 <seealso><a href="../filter.html">filters</a></seealso>
307 <name>AllowEncodedSlashes</name>
308 <description>Determines whether encoded path separators in URLs are allowed to
309 be passed through</description>
310 <syntax>AllowEncodedSlashes On|Off</syntax>
311 <default>AllowEncodedSlashes Off</default>
312 <contextlist><context>server config</context><context>virtual host</context>
314 <compatibility>Available in Apache 2.0.46 and later</compatibility>
317 <p>The <directive>AllowEncodedSlashes</directive> directive allows URLs
318 which contain encoded path separators (<code>%2F</code> for <code>/</code>
319 and additionally <code>%5C</code> for <code>\</code> on according systems)
320 to be used. Normally such URLs are refused with a 404 (Not found) error.</p>
322 <p>Turning <directive>AllowEncodedSlashes</directive> <code>On</code> is
323 mostly useful when used in conjunction with <code>PATH_INFO</code>.</p>
325 <note><title>Note</title>
326 <p>Allowing encoded slashes does <em>not</em> imply <em>decoding</em>.
327 Occurrences of <code>%2F</code> or <code>%5C</code> (<em>only</em> on
328 according systems) will be left as such in the otherwise decoded URL
332 <seealso><directive module="core">AcceptPathInfo</directive></seealso>
336 <name>AllowOverride</name>
337 <description>Types of directives that are allowed in
338 <code>.htaccess</code> files</description>
339 <syntax>AllowOverride All|None|<var>directive-type</var>
340 [<var>directive-type</var>] ...</syntax>
341 <default>AllowOverride All</default>
342 <contextlist><context>directory</context></contextlist>
345 <p>When the server finds an <code>.htaccess</code> file (as
346 specified by <directive module="core">AccessFileName</directive>)
347 it needs to know which directives declared in that file can override
348 earlier configuration directives.</p>
350 <note><title>Only available in <Directory> sections</title>
351 <directive>AllowOverride</directive> is valid only in
352 <directive type="section" module="core">Directory</directive>
353 sections specified without regular expressions, not in <directive
354 type="section" module="core">Location</directive>, <directive
355 module="core" type="section">DirectoryMatch</directive> or
356 <directive type="section" module="core">Files</directive> sections.
359 <p>When this directive is set to <code>None</code>, then
360 <a href="#accessfilename">.htaccess</a> files are completely ignored.
361 In this case, the server will not even attempt to read
362 <code>.htaccess</code> files in the filesystem.</p>
364 <p>When this directive is set to <code>All</code>, then any
365 directive which has the .htaccess <a
366 href="directive-dict.html#Context">Context</a> is allowed in
367 <code>.htaccess</code> files.</p>
369 <p>The <var>directive-type</var> can be one of the following
370 groupings of directives.</p>
377 Allow use of the authorization directives (<directive
378 module="mod_authn_dbm">AuthDBMGroupFile</directive>,
379 <directive module="mod_authn_dbm">AuthDBMUserFile</directive>,
380 <directive module="mod_authz_groupfile">AuthGroupFile</directive>,
381 <directive module="core">AuthName</directive>,
382 <directive module="core">AuthType</directive>, <directive
383 module="mod_authn_file">AuthUserFile</directive>, <directive
384 module="core">Require</directive>, <em>etc.</em>).</dd>
389 Allow use of the directives controlling document types (<directive
390 module="core">DefaultType</directive>, <directive
391 module="core">ErrorDocument</directive>, <directive
392 module="core">ForceType</directive>, <directive
393 module="mod_negotiation">LanguagePriority</directive>,
394 <directive module="core">SetHandler</directive>, <directive
395 module="core">SetInputFilter</directive>, <directive
396 module="core">SetOutputFilter</directive>, and
397 <module>mod_mime</module> Add* and Remove*
398 directives, <em>etc.</em>), document meta data (<directive
399 module="mod_headers">Header</directive>, <directive
400 module="mod_headers">RequestHeader</directive>, <directive
401 module="mod_setenvif">SetEnvIf</directive>, <directive
402 module="mod_setenvif">SetEnvIfNoCase</directive>, <directive
403 module="mod_setenvif">BrowserMatch</directive>, <directive
404 module="mod_usertrack">CookieExpires</directive>, <directive
405 module="mod_usertrack">CookieDomain</directive>, <directive
406 module="mod_usertrack">CookieStyle</directive>, <directive
407 module="mod_usertrack">CookieTracking</directive>, <directive
408 module="mod_usertrack">CookieName</directive>),
409 <module>mod_rewrite</module> directives <directive
410 module="mod_rewrite">RewriteEngine</directive>, <directive
411 module="mod_rewrite">RewriteOptions</directive>, <directive
412 module="mod_rewrite">RewriteBase</directive>, <directive
413 module="mod_rewrite">RewriteCond</directive>, <directive
414 module="mod_rewrite">RewriteRule</directive>) and
415 <directive module="mod_actions">Action</directive> from
416 <module>mod_actions</module>.
422 Allow use of the directives controlling directory indexing
424 module="mod_autoindex">AddDescription</directive>,
425 <directive module="mod_autoindex">AddIcon</directive>, <directive
426 module="mod_autoindex">AddIconByEncoding</directive>,
427 <directive module="mod_autoindex">AddIconByType</directive>,
428 <directive module="mod_autoindex">DefaultIcon</directive>, <directive
429 module="mod_dir">DirectoryIndex</directive>, <directive
430 module="mod_autoindex">FancyIndexing</directive>, <directive
431 module="mod_autoindex">HeaderName</directive>, <directive
432 module="mod_autoindex">IndexIgnore</directive>, <directive
433 module="mod_autoindex">IndexOptions</directive>, <directive
434 module="mod_autoindex">ReadmeName</directive>,
440 Allow use of the directives controlling host access (<directive
441 module="mod_authz_host">Allow</directive>, <directive
442 module="mod_authz_host">Deny</directive> and <directive
443 module="mod_authz_host">Order</directive>).</dd>
445 <dt>Options[=<var>Option</var>,...]</dt>
448 Allow use of the directives controlling specific directory
449 features (<directive module="core">Options</directive> and
450 <directive module="mod_include">XBitHack</directive>).
451 An equal sign may be given followed by a comma (but no spaces)
452 separated lists of options that may be set using the <directive
453 module="core">Options</directive> command.</dd>
459 AllowOverride AuthConfig Indexes
462 <p>In the example above all directives that are neither in the group
463 <code>AuthConfig</code> nor <code>Indexes</code> cause an internal
467 <seealso><directive module="core">AccessFileName</directive></seealso>
468 <seealso><a href="../configuring.html">Configuration Files</a></seealso>
469 <seealso><a href="../howto/htaccess.html">.htaccess Files</a></seealso>
473 <name>AuthName</name>
474 <description>Authorization realm for use in HTTP
475 authentication</description>
476 <syntax>AuthName <var>auth-domain</var></syntax>
477 <contextlist><context>directory</context><context>.htaccess</context>
479 <override>AuthConfig</override>
482 <p>This directive sets the name of the authorization realm for a
483 directory. This realm is given to the client so that the user
484 knows which username and password to send.
485 <directive>AuthName</directive> takes a single argument; if the
486 realm name contains spaces, it must be enclosed in quotation
487 marks. It must be accompanied by <directive
488 module="core">AuthType</directive> and <directive
489 module="core">Require</directive> directives, and directives such
490 as <directive module="mod_authn_file">AuthUserFile</directive> and
491 <directive module="mod_authz_groupfile">AuthGroupFile</directive> to
497 AuthName "Top Secret"
500 <p>The string provided for the <code>AuthName</code> is what will
501 appear in the password dialog provided by most browsers.</p>
504 href="../howto/auth.html">Authentication, Authorization, and
505 Access Control</a></seealso>
509 <name>AuthType</name>
510 <description>Type of user authentication</description>
511 <syntax>AuthType Basic|Digest</syntax>
512 <contextlist><context>directory</context><context>.htaccess</context>
514 <override>AuthConfig</override>
517 <p>This directive selects the type of user authentication for a
518 directory. The authentication types available are
519 <code>Basic</code> (implemented by
520 <module>mod_auth_basic</module>) and <code>Digest</code>
521 (implemented by <module>mod_auth_digest</module>).</p>
523 <p>To implement authentication, you must also use the <directive
524 module="core">AuthName</directive> and <directive
525 module="core">Require</directive> directives. In addition, the
526 server must have an authentication-provider module such as
527 <module>mod_authn_file</module> and an authorization module such
528 as <module>mod_authz_user</module>.</p>
531 <seealso><a href="../howto/auth.html">Authentication, Authorization,
532 and Access Control</a></seealso>
536 <name>CGIMapExtension</name>
537 <description>Technique for locating the interpreter for CGI
538 scripts</description>
539 <syntax>CGIMapExtension <var>cgi-path</var> <var>.extension</var></syntax>
540 <contextlist><context>directory</context><context>.htaccess</context>
542 <override>FileInfo</override>
543 <compatibility>NetWare only</compatibility>
546 <p>This directive is used to control how Apache finds the
547 interpreter used to run CGI scripts. For example, setting
548 <code>CGIMapExtension sys:\foo.nlm .foo</code> will
549 cause all CGI script files with a <code>.foo</code> extension to
550 be passed to the FOO interpreter.</p>
555 <name>ContentDigest</name>
556 <description>Enables the generation of <code>Content-MD5</code> HTTP Response
557 headers</description>
558 <syntax>ContentDigest On|Off</syntax>
559 <default>ContentDigest Off</default>
560 <contextlist><context>server config</context><context>virtual host</context>
561 <context>directory</context><context>.htaccess</context>
563 <override>Options</override>
564 <status>Experimental</status>
567 <p>This directive enables the generation of
568 <code>Content-MD5</code> headers as defined in RFC1864
569 respectively RFC2068.</p>
571 <p>MD5 is an algorithm for computing a "message digest"
572 (sometimes called "fingerprint") of arbitrary-length data, with
573 a high degree of confidence that any alterations in the data
574 will be reflected in alterations in the message digest.</p>
576 <p>The <code>Content-MD5</code> header provides an end-to-end
577 message integrity check (MIC) of the entity-body. A proxy or
578 client may check this header for detecting accidental
579 modification of the entity-body in transit. Example header:</p>
582 Content-MD5: AuLb7Dp1rqtRtxz2m9kRpA==
585 <p>Note that this can cause performance problems on your server
586 since the message digest is computed on every request (the
587 values are not cached).</p>
589 <p><code>Content-MD5</code> is only sent for documents served
590 by the <module>core</module>, and not by any module. For example,
591 SSI documents, output from CGI scripts, and byte range responses
592 do not have this header.</p>
597 <name>DefaultType</name>
598 <description>MIME content-type that will be sent if the
599 server cannot determine a type in any other way</description>
600 <syntax>DefaultType <var>MIME-type</var></syntax>
601 <default>DefaultType text/plain</default>
602 <contextlist><context>server config</context><context>virtual host</context>
603 <context>directory</context><context>.htaccess</context>
605 <override>FileInfo</override>
608 <p>There will be times when the server is asked to provide a
609 document whose type cannot be determined by its <glossary
610 ref="mime-type">MIME types</glossary> mappings.</p>
612 <p>The server must inform the client of the content-type of the
613 document, so in the event of an unknown type it uses the
614 <code>DefaultType</code>. For example:</p>
617 DefaultType image/gif
620 <p>would be appropriate for a directory which contained many GIF
621 images with filenames missing the <code>.gif</code> extension.</p>
623 <p>Note that unlike <directive
624 module="core">ForceType</directive>, this directive only
625 provides the default mime-type. All other mime-type definitions,
626 including filename extensions, that might identify the media type
627 will override this default.</p>
631 <directivesynopsis type="section">
632 <name>Directory</name>
633 <description>Enclose a group of directives that apply only to the
634 named file-system directory and sub-directories</description>
635 <syntax><Directory <var>directory-path</var>>
636 ... </Directory></syntax>
637 <contextlist><context>server config</context><context>virtual host</context>
641 <p><directive type="section">Directory</directive> and
642 <code></Directory></code> are used to enclose a group of
643 directives that will apply only to the named directory and
644 sub-directories of that directory. Any directive that is allowed
645 in a directory context may be used. <var>Directory-path</var> is
646 either the full path to a directory, or a wild-card string using
647 Unix shell-style matching. In a wild-card string, <code>?</code> matches
648 any single character, and <code>*</code> matches any sequences of
649 characters. You may also use <code>[]</code> character ranges. None
650 of the wildcards match a `/' character, so <code><Directory
651 /*/public_html></code> will not match
652 <code>/home/user/public_html</code>, but <code><Directory
653 /home/*/public_html></code> will match. Example:</p>
656 <Directory /usr/local/httpd/htdocs><br />
658 Options Indexes FollowSymLinks<br />
664 <p>Be careful with the <var>directory-path</var> arguments:
665 They have to literally match the filesystem path which Apache uses
666 to access the files. Directives applied to a particular
667 <code><Directory></code> will not apply to files accessed from
668 that same directory via a different path, such as via different symbolic
672 <p><glossary ref="regex">Regular
673 expressions</glossary> can also be used, with the addition of the
674 <code>~</code> character. For example:</p>
677 <Directory ~ "^/www/.*/[0-9]{3}">
680 <p>would match directories in <code>/www/</code> that consisted of
683 <p>If multiple (non-regular expression) <directive
684 type="section">Directory</directive> sections
685 match the directory (or one of its parents) containing a document,
686 then the directives are applied in the order of shortest match
687 first, interspersed with the directives from the <a
688 href="#accessfilename">.htaccess</a> files. For example,
692 <Directory /><br />
694 AllowOverride None<br />
696 </Directory><br />
698 <Directory /home/><br />
700 AllowOverride FileInfo<br />
705 <p>for access to the document <code>/home/web/dir/doc.html</code>
709 <li>Apply directive <code>AllowOverride None</code>
710 (disabling <code>.htaccess</code> files).</li>
712 <li>Apply directive <code>AllowOverride FileInfo</code> (for
713 directory <code>/home</code>).</li>
715 <li>Apply any <code>FileInfo</code> directives in
716 <code>/home/.htaccess</code>, <code>/home/web/.htaccess</code> and
717 <code>/home/web/dir/.htaccess</code> in that order.</li>
720 <p>Regular expressions are not considered until after all of the
721 normal sections have been applied. Then all of the regular
722 expressions are tested in the order they appeared in the
723 configuration file. For example, with</p>
726 <Directory ~ abc$><br />
728 # ... directives here ...<br />
733 <p>the regular expression section won't be considered until after
734 all normal <directive type="section">Directory</directive>s and
735 <code>.htaccess</code> files have been applied. Then the regular
736 expression will match on <code>/home/abc/public_html/abc</code> and
737 the corresponding <directive type="section">Directory</directive> will
740 <p><strong>Note that the default Apache access for
741 <code><Directory /></code> is <code>Allow from All</code>.
742 This means that Apache will serve any file mapped from an URL. It is
743 recommended that you change this with a block such
747 <Directory /><br />
749 Order Deny,Allow<br />
755 <p><strong>and then override this for directories you
756 <em>want</em> accessible. See the <a
757 href="../misc/security_tips.html">Security Tips</a> page for more
758 details.</strong></p>
760 <p>The directory sections occur in the <code>httpd.conf</code> file.
761 <directive type="section">Directory</directive> directives
762 cannot nest, and cannot appear in a <directive module="core"
763 type="section">Limit</directive> or <directive module="core"
764 type="section">LimitExcept</directive> section.</p>
766 <seealso><a href="../sections.html">How <Directory>,
767 <Location> and <Files> sections work</a> for an
768 explanation of how these different sections are combined when a
769 request is received</seealso>
772 <directivesynopsis type="section">
773 <name>DirectoryMatch</name>
774 <description>Enclose directives that apply to
775 file-system directories matching a regular expression and their
776 subdirectories</description>
777 <syntax><DirectoryMatch <var>regex</var>>
778 ... </DirectoryMatch></syntax>
779 <contextlist><context>server config</context><context>virtual host</context>
783 <p><directive type="section">DirectoryMatch</directive> and
784 <code></DirectoryMatch></code> are used to enclose a group
785 of directives which will apply only to the named directory and
786 sub-directories of that directory, the same as <directive
787 module="core" type="section">Directory</directive>. However, it
788 takes as an argument a <glossary ref="regex">regular
789 expression</glossary>. For example:</p>
792 <DirectoryMatch "^/www/(.+/)?[0-9]{3}">
795 <p>would match directories in <code>/www/</code> that consisted of three
798 <seealso><directive type="section" module="core">Directory</directive> for
799 a description of how regular expressions are mixed in with normal
800 <directive type="section">Directory</directive>s</seealso>
802 href="../sections.html">How <Directory>, <Location> and
803 <Files> sections work</a> for an explanation of how these different
804 sections are combined when a request is received</seealso>
808 <name>DocumentRoot</name>
809 <description>Directory that forms the main document tree visible
810 from the web</description>
811 <syntax>DocumentRoot <var>directory-path</var></syntax>
812 <default>DocumentRoot /usr/local/apache/htdocs</default>
813 <contextlist><context>server config</context><context>virtual host</context>
817 <p>This directive sets the directory from which <program>httpd</program>
818 will serve files. Unless matched by a directive like <directive
819 module="mod_alias">Alias</directive>, the server appends the
820 path from the requested URL to the document root to make the
821 path to the document. Example:</p>
824 DocumentRoot /usr/web
828 <code>http://www.my.host.com/index.html</code> refers to
829 <code>/usr/web/index.html</code>. If the <var>directory-path</var> is
830 not absolute then it is assumed to be relative to the <directive
831 module="core">ServerRoot</directive>.</p>
833 <p>The <directive>DocumentRoot</directive> should be specified without
834 a trailing slash.</p>
836 <seealso><a href="../urlmapping.html">Mapping URLs to Filesystem
837 Location</a></seealso>
841 <name>EnableMMAP</name>
842 <description>Use memory-mapping to read files during delivery</description>
843 <syntax>EnableMMAP On|Off</syntax>
844 <default>EnableMMAP On</default>
845 <contextlist><context>server config</context><context>virtual host</context>
846 <context>directory</context><context>.htaccess</context>
848 <override>FileInfo</override>
851 <p>This directive controls whether the <program>httpd</program> may use
852 memory-mapping if it needs to read the contents of a file during
853 delivery. By default, when the handling of a request requires
854 access to the data within a file -- for example, when delivering a
855 server-parsed file using <module>mod_include</module> -- Apache
856 memory-maps the file if the OS supports it.</p>
858 <p>This memory-mapping sometimes yields a performance improvement.
859 But in some environments, it is better to disable the memory-mapping
860 to prevent operational problems:</p>
863 <li>On some multiprocessor systems, memory-mapping can reduce the
864 performance of the <program>httpd</program>.</li>
865 <li>With an NFS-mounted <directive module="core">DocumentRoot</directive>,
866 the <program>httpd</program> may crash due to a segmentation fault if a file
867 is deleted or truncated while the <program>httpd</program> has it
871 <p>For server configurations that are vulnerable to these problems,
872 you should disable memory-mapping of delivered files by specifying:</p>
878 <p>For NFS mounted files, this feature may be disabled explicitly for
879 the offending files by specifying:</p>
882 <Directory "/path-to-nfs-files">
892 <name>EnableSendfile</name>
893 <description>Use the kernel sendfile support to deliver files to the client</description>
894 <syntax>EnableSendfile On|Off</syntax>
895 <default>EnableSendfile On</default>
896 <contextlist><context>server config</context><context>virtual host</context>
897 <context>directory</context><context>.htaccess</context>
899 <override>FileInfo</override>
900 <compatibility>Available in version 2.0.44 and later</compatibility>
903 <p>This directive controls whether <program>httpd</program> may use the
904 sendfile support from the kernel to transmit file contents to the client.
905 By default, when the handling of a request requires no access
906 to the data within a file -- for example, when delivering a
907 static file -- Apache uses sendfile to deliver the file contents
908 without ever reading the file if the OS supports it.</p>
910 <p>This sendfile mechanism avoids separate read and send operations,
911 and buffer allocations. But on some platforms or within some
912 filesystems, it is better to disable this feature to avoid
913 operational problems:</p>
916 <li>Some platforms may have broken sendfile support that the build
917 system did not detect, especially if the binaries were built on
918 another box and moved to such a machine with broken sendfile
920 <li>On Linux the use of sendfile triggers TCP-checksum
921 offloading bugs on certain networking cards when using IPv6.</li>
922 <li>On Linux on Itanium, sendfile may be unable to handle files
923 over 2GB in size.</li>
924 <li>With a network-mounted <directive
925 module="core">DocumentRoot</directive> (e.g., NFS or SMB),
926 the kernel may be unable to serve the network file through
930 <p>For server configurations that are vulnerable to these problems,
931 you should disable this feature by specifying:</p>
937 <p>For NFS or SMB mounted files, this feature may be disabled explicitly
938 for the offending files by specifying:</p>
941 <Directory "/path-to-nfs-files">
951 <name>ErrorDocument</name>
952 <description>What the server will return to the client
953 in case of an error</description>
954 <syntax>ErrorDocument <var>error-code</var> <var>document</var></syntax>
955 <contextlist><context>server config</context><context>virtual host</context>
956 <context>directory</context><context>.htaccess</context>
958 <override>FileInfo</override>
959 <compatibility>Quoting syntax for text messages is different in Apache
963 <p>In the event of a problem or error, Apache can be configured
964 to do one of four things,</p>
967 <li>output a simple hardcoded error message</li>
969 <li>output a customized message</li>
971 <li>redirect to a local <var>URL-path</var> to handle the
974 <li>redirect to an external <var>URL</var> to handle the
978 <p>The first option is the default, while options 2-4 are
979 configured using the <directive>ErrorDocument</directive>
980 directive, which is followed by the HTTP response code and a URL
981 or a message. Apache will sometimes offer additional information
982 regarding the problem/error.</p>
984 <p>URLs can begin with a slash (/) for local web-paths (relative
985 to the <directive module="core">DocumentRoot</directive>), or be a
986 full URL which the client can resolve. Alternatively, a message
987 can be provided to be displayed by the browser. Examples:</p>
990 ErrorDocument 500 http://foo.example.com/cgi-bin/tester<br />
991 ErrorDocument 404 /cgi-bin/bad_urls.pl<br />
992 ErrorDocument 401 /subscription_info.html<br />
993 ErrorDocument 403 "Sorry can't allow you access today"
996 <p>Additionally, the special value <code>default</code> can be used
997 to specify Apache's simple hardcoded message. While not required
998 under normal circumstances, <code>default</code> will restore
999 Apache's simple hardcoded message for configurations that would
1000 otherwise inherit an existing <directive>ErrorDocument</directive>.</p>
1003 ErrorDocument 404 /cgi-bin/bad_urls.pl<br /><br />
1004 <Directory /web/docs><br />
1006 ErrorDocument 404 default<br />
1011 <p>Note that when you specify an <directive>ErrorDocument</directive>
1012 that points to a remote URL (ie. anything with a method such as
1013 <code>http</code> in front of it), Apache will send a redirect to the
1014 client to tell it where to find the document, even if the
1015 document ends up being on the same server. This has several
1016 implications, the most important being that the client will not
1017 receive the original error status code, but instead will
1018 receive a redirect status code. This in turn can confuse web
1019 robots and other clients which try to determine if a URL is
1020 valid using the status code. In addition, if you use a remote
1021 URL in an <code>ErrorDocument 401</code>, the client will not
1022 know to prompt the user for a password since it will not
1023 receive the 401 status code. Therefore, <strong>if you use an
1024 <code>ErrorDocument 401</code> directive then it must refer to a local
1025 document.</strong></p>
1027 <p>Microsoft Internet Explorer (MSIE) will by default ignore
1028 server-generated error messages when they are "too small" and substitute
1029 its own "friendly" error messages. The size threshold varies depending on
1030 the type of error, but in general, if you make your error document
1031 greater than 512 bytes, then MSIE will show the server-generated
1032 error rather than masking it. More information is available in
1033 Microsoft Knowledge Base article <a
1034 href="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q294807"
1037 <p>Although most error messages can be overriden, there are certain
1038 circumstances where the internal messages are used regardless of the
1039 setting of <directive module="core">ErrorDocument</directive>. In
1040 particular, if a malformed request is detected, normal request processing
1041 will be immediately halted and the internal error message returned.
1042 This is necessary to guard against security problems caused by
1045 <p>Prior to version 2.0, messages were indicated by prefixing
1046 them with a single unmatched double quote character.</p>
1049 <seealso><a href="../custom-error.html">documentation of
1050 customizable responses</a></seealso>
1051 </directivesynopsis>
1054 <name>ErrorLog</name>
1055 <description>Location where the server will log errors</description>
1056 <syntax> ErrorLog <var>file-path</var>|syslog[:<var>facility</var>]</syntax>
1057 <default>ErrorLog logs/error_log (Unix) ErrorLog logs/error.log (Windows and OS/2)</default>
1058 <contextlist><context>server config</context><context>virtual host</context>
1062 <p>The <directive>ErrorLog</directive> directive sets the name of
1063 the file to which the server will log any errors it encounters. If
1064 the <var>file-path</var> is not absolute then it is assumed to be
1065 relative to the <directive module="core">ServerRoot</directive>.</p>
1067 <example><title>Example</title>
1068 ErrorLog /var/log/httpd/error_log
1071 <p>If the <var>file-path</var>
1072 begins with a pipe (|) then it is assumed to be a command to spawn
1073 to handle the error log.</p>
1075 <example><title>Example</title>
1076 ErrorLog "|/usr/local/bin/httpd_errors"
1079 <p>Using <code>syslog</code> instead of a filename enables logging
1080 via syslogd(8) if the system supports it. The default is to use
1081 syslog facility <code>local7</code>, but you can override this by
1082 using the <code>syslog:<var>facility</var></code> syntax where
1083 <var>facility</var> can be one of the names usually documented in
1086 <example><title>Example</title>
1087 ErrorLog syslog:user
1090 <p>SECURITY: See the <a
1091 href="../misc/security_tips.html#serverroot">security tips</a>
1092 document for details on why your security could be compromised
1093 if the directory where log files are stored is writable by
1094 anyone other than the user that starts the server.</p>
1095 <note type="warning"><title>Note</title>
1096 <p>When entering a file path on non-Unix platforms, care should be taken
1097 to make sure that only forward slashed are used even though the platform
1098 may allow the use of back slashes. In general it is a good idea to always
1099 use forward slashes throughout the configuration files.</p>
1102 <seealso><directive module="core">LogLevel</directive></seealso>
1103 <seealso><a href="../logs.html">Apache Log Files</a></seealso>
1104 </directivesynopsis>
1107 <name>FileETag</name>
1108 <description>File attributes used to create the ETag
1109 HTTP response header</description>
1110 <syntax>FileETag <var>component</var> ...</syntax>
1111 <default>FileETag INode MTime Size</default>
1112 <contextlist><context>server config</context><context>virtual host</context>
1113 <context>directory</context><context>.htaccess</context>
1115 <override>FileInfo</override>
1119 The <directive>FileETag</directive> directive configures the file
1120 attributes that are used to create the <code>ETag</code> (entity
1121 tag) response header field when the document is based on a file.
1122 (The <code>ETag</code> value is used in cache management to save
1123 network bandwidth.) In Apache 1.3.22 and earlier, the
1124 <code>ETag</code> value was <em>always</em> formed
1125 from the file's inode, size, and last-modified time (mtime). The
1126 <directive>FileETag</directive> directive allows you to choose
1127 which of these -- if any -- should be used. The recognized keywords are:
1131 <dt><strong>INode</strong></dt>
1132 <dd>The file's i-node number will be included in the calculation</dd>
1133 <dt><strong>MTime</strong></dt>
1134 <dd>The date and time the file was last modified will be included</dd>
1135 <dt><strong>Size</strong></dt>
1136 <dd>The number of bytes in the file will be included</dd>
1137 <dt><strong>All</strong></dt>
1138 <dd>All available fields will be used. This is equivalent to:
1139 <example>FileETag INode MTime Size</example></dd>
1140 <dt><strong>None</strong></dt>
1141 <dd>If a document is file-based, no <code>ETag</code> field will be
1142 included in the response</dd>
1145 <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
1146 keywords may be prefixed with either <code>+</code> or <code>-</code>,
1147 which allow changes to be made to the default setting inherited
1148 from a broader scope. Any keyword appearing without such a prefix
1149 immediately and completely cancels the inherited setting.</p>
1151 <p>If a directory's configuration includes
1152 <code>FileETag INode MTime Size</code>, and a
1153 subdirectory's includes <code>FileETag -INode</code>,
1154 the setting for that subdirectory (which will be inherited by
1155 any sub-subdirectories that don't override it) will be equivalent to
1156 <code>FileETag MTime Size</code>.</p>
1158 </directivesynopsis>
1160 <directivesynopsis type="section">
1162 <description>Contains directives that apply to matched
1163 filenames</description>
1164 <syntax><Files <var>filename</var>> ... </Files></syntax>
1165 <contextlist><context>server config</context><context>virtual host</context>
1166 <context>directory</context><context>.htaccess</context>
1168 <override>All</override>
1171 <p>The <directive type="section">Files</directive> directive
1172 limits the scope of the enclosed directives by filename. It is comparable
1173 to the <directive module="core" type="section">Directory</directive>
1174 and <directive module="core" type="section">Location</directive>
1175 directives. It should be matched with a <code></Files></code>
1176 directive. The directives given within this section will be applied to
1177 any object with a basename (last component of filename) matching the
1178 specified filename. <directive type="section">Files</directive>
1179 sections are processed in the order they appear in the
1180 configuration file, after the <directive module="core"
1181 type="section">Directory</directive> sections and
1182 <code>.htaccess</code> files are read, but before <directive
1183 type="section" module="core">Location</directive> sections. Note
1184 that <directive type="section">Files</directive> can be nested
1185 inside <directive type="section"
1186 module="core">Directory</directive> sections to restrict the
1187 portion of the filesystem they apply to.</p>
1189 <p>The <var>filename</var> argument should include a filename, or
1190 a wild-card string, where <code>?</code> matches any single character,
1191 and <code>*</code> matches any sequences of characters.
1192 <glossary ref="regex">Regular expressions</glossary>
1193 can also be used, with the addition of the
1194 <code>~</code> character. For example:</p>
1197 <Files ~ "\.(gif|jpe?g|png)$">
1200 <p>would match most common Internet graphics formats. <directive
1201 module="core" type="section">FilesMatch</directive> is preferred,
1204 <p>Note that unlike <directive type="section"
1205 module="core">Directory</directive> and <directive type="section"
1206 module="core">Location</directive> sections, <directive
1207 type="section">Files</directive> sections can be used inside
1208 <code>.htaccess</code> files. This allows users to control access to
1209 their own files, at a file-by-file level.</p>
1212 <seealso><a href="../sections.html">How <Directory>, <Location>
1213 and <Files> sections work</a> for an explanation of how these
1214 different sections are combined when a request is received</seealso>
1215 </directivesynopsis>
1217 <directivesynopsis type="section">
1218 <name>FilesMatch</name>
1219 <description>Contains directives that apply to regular-expression matched
1220 filenames</description>
1221 <syntax><FilesMatch <var>regex</var>> ... </FilesMatch></syntax>
1222 <contextlist><context>server config</context><context>virtual host</context>
1223 <context>directory</context><context>.htaccess</context>
1225 <override>All</override>
1228 <p>The <directive type="section">FilesMatch</directive> directive
1229 limits the scope of the enclosed directives by filename, just as the
1230 <directive module="core" type="section">Files</directive> directive
1231 does. However, it accepts a <glossary ref="regex">regular
1232 expression</glossary>. For example:</p>
1235 <FilesMatch "\.(gif|jpe?g|png)$">
1238 <p>would match most common Internet graphics formats.</p>
1241 <seealso><a href="../sections.html">How <Directory>, <Location>
1242 and <Files> sections work</a> for an explanation of how these
1243 different sections are combined when a request is received</seealso>
1244 </directivesynopsis>
1247 <name>ForceType</name>
1248 <description>Forces all matching files to be served with the specified
1249 MIME content-type</description>
1250 <syntax>ForceType <var>MIME-type</var>|None</syntax>
1251 <contextlist><context>directory</context><context>.htaccess</context>
1253 <override>FileInfo</override>
1254 <compatibility>Moved to the core in Apache 2.0</compatibility>
1257 <p>When placed into an <code>.htaccess</code> file or a
1258 <directive type="section" module="core">Directory</directive>, or
1259 <directive type="section" module="core">Location</directive> or
1260 <directive type="section" module="core">Files</directive>
1261 section, this directive forces all matching files to be served
1262 with the content type identification given by
1263 <var>MIME-type</var>. For example, if you had a directory full of
1264 GIF files, but did not want to label them all with <code>.gif</code>,
1265 you might want to use:</p>
1271 <p>Note that unlike <directive module="core">DefaultType</directive>,
1272 this directive overrides all mime-type associations, including
1273 filename extensions, that might identify the media type.</p>
1275 <p>You can override any <directive>ForceType</directive> setting
1276 by using the value of <code>None</code>:</p>
1279 # force all files to be image/gif:<br />
1280 <Location /images><br />
1282 ForceType image/gif<br />
1284 </Location><br />
1286 # but normal mime-type associations here:<br />
1287 <Location /images/mixed><br />
1289 ForceType None<br />
1294 </directivesynopsis>
1297 <name>HostnameLookups</name>
1298 <description>Enables DNS lookups on client IP addresses</description>
1299 <syntax>HostnameLookups On|Off|Double</syntax>
1300 <default>HostnameLookups Off</default>
1301 <contextlist><context>server config</context><context>virtual host</context>
1302 <context>directory</context></contextlist>
1305 <p>This directive enables DNS lookups so that host names can be
1306 logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
1307 The value <code>Double</code> refers to doing double-reverse
1308 DNS lookup. That is, after a reverse lookup is performed, a forward
1309 lookup is then performed on that result. At least one of the IP
1310 addresses in the forward lookup must match the original
1311 address. (In "tcpwrappers" terminology this is called
1312 <code>PARANOID</code>.)</p>
1314 <p>Regardless of the setting, when <module>mod_authz_host</module> is
1315 used for controlling access by hostname, a double reverse lookup
1316 will be performed. This is necessary for security. Note that the
1317 result of this double-reverse isn't generally available unless you
1318 set <code>HostnameLookups Double</code>. For example, if only
1319 <code>HostnameLookups On</code> and a request is made to an object
1320 that is protected by hostname restrictions, regardless of whether
1321 the double-reverse fails or not, CGIs will still be passed the
1322 single-reverse result in <code>REMOTE_HOST</code>.</p>
1324 <p>The default is <code>Off</code> in order to save the network
1325 traffic for those sites that don't truly need the reverse
1326 lookups done. It is also better for the end users because they
1327 don't have to suffer the extra latency that a lookup entails.
1328 Heavily loaded sites should leave this directive
1329 <code>Off</code>, since DNS lookups can take considerable
1330 amounts of time. The utility <program>logresolve</program>, compiled by
1331 default to the <code>bin</code> subdirectory of your installation
1332 directory, can be used to look up host names from logged IP addresses
1335 </directivesynopsis>
1337 <directivesynopsis type="section">
1338 <name>IfDefine</name>
1339 <description>Encloses directives that will be processed only
1340 if a test is true at startup</description>
1341 <syntax><IfDefine [!]<var>parameter-name</var>> ...
1342 </IfDefine></syntax>
1343 <contextlist><context>server config</context><context>virtual host</context>
1344 <context>directory</context><context>.htaccess</context>
1346 <override>All</override>
1349 <p>The <code><IfDefine <var>test</var>>...</IfDefine>
1350 </code> section is used to mark directives that are conditional. The
1351 directives within an <directive type="section">IfDefine</directive>
1352 section are only processed if the <var>test</var> is true. If <var>
1353 test</var> is false, everything between the start and end markers is
1356 <p>The <var>test</var> in the <directive type="section"
1357 >IfDefine</directive> section directive can be one of two forms:</p>
1360 <li><var>parameter-name</var></li>
1362 <li><code>!</code><var>parameter-name</var></li>
1365 <p>In the former case, the directives between the start and end
1366 markers are only processed if the parameter named
1367 <var>parameter-name</var> is defined. The second format reverses
1368 the test, and only processes the directives if
1369 <var>parameter-name</var> is <strong>not</strong> defined.</p>
1371 <p>The <var>parameter-name</var> argument is a define as given on
1372 the <program>httpd</program> command line via <code>-D<var>parameter-</var>
1373 </code>, at the time the server was started.</p>
1375 <p><directive type="section">IfDefine</directive> sections are
1376 nest-able, which can be used to implement simple
1377 multiple-parameter tests. Example:</p>
1380 httpd -DReverseProxy ...<br />
1383 <IfDefine ReverseProxy><br />
1385 LoadModule rewrite_module modules/mod_rewrite.so<br />
1386 LoadModule proxy_module modules/libproxy.so<br />
1391 </directivesynopsis>
1393 <directivesynopsis type="section">
1394 <name>IfModule</name>
1395 <description>Encloses directives that are processed conditional on the
1396 presence or absence of a specific module</description>
1397 <syntax><IfModule [!]<var>module-file</var>|<var>module-identifier</var>> ...
1398 </IfModule></syntax>
1399 <contextlist><context>server config</context><context>virtual host</context>
1400 <context>directory</context><context>.htaccess</context>
1402 <override>All</override>
1403 <compatibility>Module identifiers are available in version 2.1 and
1404 later.</compatibility>
1407 <p>The <code><IfModule <var>test</var>>...</IfModule></code>
1408 section is used to mark directives that are conditional on the presence of
1409 a specific module. The directives within an <directive type="section"
1410 >IfModule</directive> section are only processed if the <var>test</var>
1411 is true. If <var>test</var> is false, everything between the start and
1412 end markers is ignored.</p>
1414 <p>The <var>test</var> in the <directive type="section"
1415 >IfModule</directive> section directive can be one of two forms:</p>
1418 <li><var>module</var></li>
1420 <li>!<var>module</var></li>
1423 <p>In the former case, the directives between the start and end
1424 markers are only processed if the module named <var>module</var>
1425 is included in Apache -- either compiled in or
1426 dynamically loaded using <directive module="mod_so"
1427 >LoadModule</directive>. The second format reverses the test,
1428 and only processes the directives if <var>module</var> is
1429 <strong>not</strong> included.</p>
1431 <p>The <var>module</var> argument can be either the module identifier or
1432 the file name of the module, at the time it was compiled. For example,
1433 <code>rewrite_module</code> is the identifier and
1434 <code>mod_rewrite.c</code> is the file name. If a module consists of
1435 several source files, use the name of the file containing the string
1436 <code>STANDARD20_MODULE_STUFF</code>.</p>
1438 <p><directive type="section">IfModule</directive> sections are
1439 nest-able, which can be used to implement simple multiple-module
1442 <note>This section should only be used if you need to have one
1443 configuration file that works whether or not a specific module
1444 is available. In normal operation, directives need not be
1445 placed in <directive type="section">IfModule</directive>
1448 </directivesynopsis>
1451 <name>Include</name>
1452 <description>Includes other configuration files from within
1453 the server configuration files</description>
1454 <syntax>Include <var>file-path</var>|<var>directory-path</var></syntax>
1455 <contextlist><context>server config</context><context>virtual host</context>
1456 <context>directory</context>
1458 <compatibility>Wildcard matching available in 2.0.41 and later</compatibility>
1461 <p>This directive allows inclusion of other configuration files
1462 from within the server configuration files.</p>
1464 <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used to
1465 include several files at once, in alphabetical order. In
1466 addition, if <directive>Include</directive> points to a directory,
1467 rather than a file, Apache will read all files in that directory
1468 and any subdirectory. But including entire directories is not
1469 recommended, because it is easy to accidentally leave temporary
1470 files in a directory that can cause <program>httpd</program> to
1473 <p>The file path specified may be an absolute path, or may be relative
1474 to the <directive module="core">ServerRoot</directive> directory.</p>
1479 Include /usr/local/apache2/conf/ssl.conf<br />
1480 Include /usr/local/apache2/conf/vhosts/*.conf
1483 <p>Or, providing paths relative to your <directive
1484 module="core">ServerRoot</directive> directory:</p>
1487 Include conf/ssl.conf<br />
1488 Include conf/vhosts/*.conf
1491 <p>Running <code>apachectl configtest</code> will give you a list
1492 of the files that are being processed during the configuration
1496 root@host# apachectl configtest<br />
1497 Processing config file: /usr/local/apache2/conf/ssl.conf<br />
1498 Processing config file: /usr/local/apache2/conf/vhosts/vhost1.conf<br />
1499 Processing config file: /usr/local/apache2/conf/vhosts/vhost2.conf<br />
1504 <seealso><program>apachectl</program></seealso>
1505 </directivesynopsis>
1508 <name>KeepAlive</name>
1509 <description>Enables HTTP persistent connections</description>
1510 <syntax>KeepAlive On|Off</syntax>
1511 <default>KeepAlive On</default>
1512 <contextlist><context>server config</context><context>virtual host</context>
1516 <p>The Keep-Alive extension to HTTP/1.0 and the persistent
1517 connection feature of HTTP/1.1 provide long-lived HTTP sessions
1518 which allow multiple requests to be sent over the same TCP
1519 connection. In some cases this has been shown to result in an
1520 almost 50% speedup in latency times for HTML documents with
1521 many images. To enable Keep-Alive connections, set
1522 <code>KeepAlive On</code>.</p>
1524 <p>For HTTP/1.0 clients, Keep-Alive connections will only be
1525 used if they are specifically requested by a client. In
1526 addition, a Keep-Alive connection with an HTTP/1.0 client can
1527 only be used when the length of the content is known in
1528 advance. This implies that dynamic content such as CGI output,
1529 SSI pages, and server-generated directory listings will
1530 generally not use Keep-Alive connections to HTTP/1.0 clients.
1531 For HTTP/1.1 clients, persistent connections are the default
1532 unless otherwise specified. If the client requests it, chunked
1533 encoding will be used in order to send content of unknown
1534 length over persistent connections.</p>
1536 <p>When a client uses a Keep-Alive connection it will be counted
1537 as a single "request" for the MaxRequestsPerChild directive, regardless
1538 of how many requests are sent using the connection.</p>
1541 <seealso><directive module="core">MaxKeepAliveRequests</directive></seealso>
1542 </directivesynopsis>
1545 <name>KeepAliveTimeout</name>
1546 <description>Amount of time the server will wait for subsequent
1547 requests on a persistent connection</description>
1548 <syntax>KeepAliveTimeout <var>seconds</var></syntax>
1549 <default>KeepAliveTimeout 5</default>
1550 <contextlist><context>server config</context><context>virtual host</context>
1554 <p>The number of seconds Apache will wait for a subsequent
1555 request before closing the connection. Once a request has been
1556 received, the timeout value specified by the
1557 <directive module="core">Timeout</directive> directive applies.</p>
1559 <p>Setting <directive>KeepAliveTimeout</directive> to a high value
1560 may cause performance problems in heavily loaded servers. The
1561 higher the timeout, the more server processes will be kept
1562 occupied waiting on connections with idle clients.</p>
1564 </directivesynopsis>
1566 <directivesynopsis type="section">
1568 <description>Restrict enclosed access controls to only certain HTTP
1569 methods</description>
1570 <syntax><Limit <var>method</var> [<var>method</var>] ... > ...
1571 </Limit></syntax>
1572 <contextlist><context>server config</context><context>virtual host</context>
1573 <context>directory</context><context>.htaccess</context>
1575 <override>All</override>
1578 <p>Access controls are normally effective for
1579 <strong>all</strong> access methods, and this is the usual
1580 desired behavior. <strong>In the general case, access control
1581 directives should not be placed within a
1582 <directive type="section">Limit</directive> section.</strong></p>
1584 <p>The purpose of the <directive type="section">Limit</directive>
1585 directive is to restrict the effect of the access controls to the
1586 nominated HTTP methods. For all other methods, the access
1587 restrictions that are enclosed in the <directive
1588 type="section">Limit</directive> bracket <strong>will have no
1589 effect</strong>. The following example applies the access control
1590 only to the methods <code>POST</code>, <code>PUT</code>, and
1591 <code>DELETE</code>, leaving all other methods unprotected:</p>
1594 <Limit POST PUT DELETE><br />
1596 Require valid-user<br />
1601 <p>The method names listed can be one or more of: <code>GET</code>,
1602 <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
1603 <code>CONNECT</code>, <code>OPTIONS</code>,
1604 <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
1605 <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
1606 <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
1607 case-sensitive.</strong> If <code>GET</code> is used it will also
1608 restrict <code>HEAD</code> requests. The <code>TRACE</code> method
1609 cannot be limited.</p>
1611 <note type="warning">A <directive type="section"
1612 module="core">LimitExcept</directive> section should always be
1613 used in preference to a <directive type="section"
1614 module="core">Limit</directive> section when restricting access,
1615 since a <directive type="section"
1616 module="core">LimitExcept</directive> section provides protection
1617 against arbitrary methods.</note>
1620 </directivesynopsis>
1622 <directivesynopsis type="section">
1623 <name>LimitExcept</name>
1624 <description>Restrict access controls to all HTTP methods
1625 except the named ones</description>
1626 <syntax><LimitExcept <var>method</var> [<var>method</var>] ... > ...
1627 </LimitExcept></syntax>
1628 <contextlist><context>server config</context><context>virtual host</context>
1629 <context>directory</context><context>.htaccess</context>
1631 <override>All</override>
1634 <p><directive type="section">LimitExcept</directive> and
1635 <code></LimitExcept></code> are used to enclose
1636 a group of access control directives which will then apply to any
1637 HTTP access method <strong>not</strong> listed in the arguments;
1638 i.e., it is the opposite of a <directive type="section"
1639 module="core">Limit</directive> section and can be used to control
1640 both standard and nonstandard/unrecognized methods. See the
1641 documentation for <directive module="core"
1642 type="section">Limit</directive> for more details.</p>
1647 <LimitExcept POST GET><br />
1649 Require valid-user<br />
1651 </LimitExcept>
1655 </directivesynopsis>
1658 <name>LimitInternalRecursion</name>
1659 <description>Determine maximum number of internal redirects and nested
1660 subrequests</description>
1661 <syntax>LimitInternalRecursion <var>number</var> [<var>number</var>]</syntax>
1662 <default>LimitInternalRecursion 10</default>
1663 <contextlist><context>server config</context><context>virtual host</context>
1665 <compatibility>Available in Apache 2.0.47 and later</compatibility>
1668 <p>An internal redirect happens, for example, when using the <directive
1669 module="mod_actions">Action</directive> directive, which internally
1670 redirects the original request to a CGI script. A subrequest is Apache's
1671 mechanism to find out what would happen for some URI if it were requested.
1672 For example, <module>mod_dir</module> uses subrequests to look for the
1673 files listed in the <directive module="mod_dir">DirectoryIndex</directive>
1676 <p><directive>LimitInternalRecursion</directive> prevents the server
1677 from crashing when entering an infinite loop of internal redirects or
1678 subrequests. Such loops are usually caused by misconfigurations.</p>
1680 <p>The directive stores two different limits, which are evaluated on
1681 per-request basis. The first <var>number</var> is the maximum number of
1682 internal redirects, that may follow each other. The second <var>number</var>
1683 determines, how deep subrequests may be nested. If you specify only one
1684 <var>number</var>, it will be assigned to both limits.</p>
1686 <example><title>Example</title>
1687 LimitInternalRecursion 5
1690 </directivesynopsis>
1693 <name>LimitRequestBody</name>
1694 <description>Restricts the total size of the HTTP request body sent
1695 from the client</description>
1696 <syntax>LimitRequestBody <var>bytes</var></syntax>
1697 <default>LimitRequestBody 0</default>
1698 <contextlist><context>server config</context><context>virtual host</context>
1699 <context>directory</context><context>.htaccess</context>
1701 <override>All</override>
1704 <p>This directive specifies the number of <var>bytes</var> from 0
1705 (meaning unlimited) to 2147483647 (2GB) that are allowed in a
1708 <p>The <directive>LimitRequestBody</directive> directive allows
1709 the user to set a limit on the allowed size of an HTTP request
1710 message body within the context in which the directive is given
1711 (server, per-directory, per-file or per-location). If the client
1712 request exceeds that limit, the server will return an error
1713 response instead of servicing the request. The size of a normal
1714 request message body will vary greatly depending on the nature of
1715 the resource and the methods allowed on that resource. CGI scripts
1716 typically use the message body for retrieving form information.
1717 Implementations of the <code>PUT</code> method will require
1718 a value at least as large as any representation that the server
1719 wishes to accept for that resource.</p>
1721 <p>This directive gives the server administrator greater
1722 control over abnormal client request behavior, which may be
1723 useful for avoiding some forms of denial-of-service
1726 <p>If, for example, you are permitting file upload to a particular
1727 location, and wish to limit the size of the uploaded file to 100K,
1728 you might use the following directive:</p>
1731 LimitRequestBody 102400
1735 </directivesynopsis>
1738 <name>LimitRequestFields</name>
1739 <description>Limits the number of HTTP request header fields that
1740 will be accepted from the client</description>
1741 <syntax>LimitRequestFields <var>number</var></syntax>
1742 <default>LimitRequestFields 100</default>
1743 <contextlist><context>server config</context></contextlist>
1746 <p><var>Number</var> is an integer from 0 (meaning unlimited) to
1747 32767. The default value is defined by the compile-time
1748 constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
1751 <p>The <directive>LimitRequestFields</directive> directive allows
1752 the server administrator to modify the limit on the number of
1753 request header fields allowed in an HTTP request. A server needs
1754 this value to be larger than the number of fields that a normal
1755 client request might include. The number of request header fields
1756 used by a client rarely exceeds 20, but this may vary among
1757 different client implementations, often depending upon the extent
1758 to which a user has configured their browser to support detailed
1759 content negotiation. Optional HTTP extensions are often expressed
1760 using request header fields.</p>
1762 <p>This directive gives the server administrator greater
1763 control over abnormal client request behavior, which may be
1764 useful for avoiding some forms of denial-of-service attacks.
1765 The value should be increased if normal clients see an error
1766 response from the server that indicates too many fields were
1767 sent in the request.</p>
1772 LimitRequestFields 50
1776 </directivesynopsis>
1779 <name>LimitRequestFieldSize</name>
1780 <description>Limits the size of the HTTP request header allowed from the
1781 client</description>
1782 <syntax>LimitRequestFieldsize <var>bytes</var></syntax>
1783 <default>LimitRequestFieldsize 8190</default>
1784 <contextlist><context>server config</context></contextlist>
1787 <p>This directive specifies the number of <var>bytes</var>
1788 that will be allowed in an HTTP request header.</p>
1790 <p>The <directive>LimitRequestFieldSize</directive> directive
1791 allows the server administrator to reduce or increase the limit
1792 on the allowed size of an HTTP request header field. A server
1793 needs this value to be large enough to hold any one header field
1794 from a normal client request. The size of a normal request header
1795 field will vary greatly among different client implementations,
1796 often depending upon the extent to which a user has configured
1797 their browser to support detailed content negotiation. SPNEGO
1798 authentication headers can be up to 12392 bytes.</p>
1800 <p>This directive gives the server administrator greater
1801 control over abnormal client request behavior, which may be
1802 useful for avoiding some forms of denial-of-service attacks.</p>
1807 LimitRequestFieldSize 4094
1810 <note>Under normal conditions, the value should not be changed from
1814 </directivesynopsis>
1817 <name>LimitRequestLine</name>
1818 <description>Limit the size of the HTTP request line that will be accepted
1819 from the client</description>
1820 <syntax>LimitRequestLine <var>bytes</var></syntax>
1821 <default>LimitRequestLine 8190</default>
1822 <contextlist><context>server config</context></contextlist>
1825 <p>This directive sets the number of <var>bytes</var> that will be
1826 allowed on the HTTP request-line.</p>
1828 <p>The <directive>LimitRequestLine</directive> directive allows
1829 the server administrator to reduce or increase the limit on the allowed size
1830 of a client's HTTP request-line. Since the request-line consists of the
1831 HTTP method, URI, and protocol version, the
1832 <directive>LimitRequestLine</directive> directive places a
1833 restriction on the length of a request-URI allowed for a request
1834 on the server. A server needs this value to be large enough to
1835 hold any of its resource names, including any information that
1836 might be passed in the query part of a <code>GET</code> request.</p>
1838 <p>This directive gives the server administrator greater
1839 control over abnormal client request behavior, which may be
1840 useful for avoiding some forms of denial-of-service attacks.</p>
1845 LimitRequestLine 4094
1848 <note>Under normal conditions, the value should not be changed from
1851 </directivesynopsis>
1854 <name>LimitXMLRequestBody</name>
1855 <description>Limits the size of an XML-based request body</description>
1856 <syntax>LimitXMLRequestBody <var>bytes</var></syntax>
1857 <default>LimitXMLRequestBody 1000000</default>
1858 <contextlist><context>server config</context><context>virtual host</context>
1859 <context>directory</context><context>.htaccess</context></contextlist>
1860 <override>All</override>
1863 <p>Limit (in bytes) on maximum size of an XML-based request
1864 body. A value of <code>0</code> will disable any checking.</p>
1869 LimitXMLRequestBody 0
1873 </directivesynopsis>
1875 <directivesynopsis type="section">
1876 <name>Location</name>
1877 <description>Applies the enclosed directives only to matching
1879 <syntax><Location
1880 <var>URL-path</var>|<var>URL</var>> ... </Location></syntax>
1881 <contextlist><context>server config</context><context>virtual host</context>
1885 <p>The <directive type="section">Location</directive> directive
1886 limits the scope of the enclosed directives by URL. It is similar to the
1887 <directive type="section" module="core">Directory</directive>
1888 directive, and starts a subsection which is terminated with a
1889 <code></Location></code> directive. <directive
1890 type="section">Location</directive> sections are processed in the
1891 order they appear in the configuration file, after the <directive
1892 type="section" module="core">Directory</directive> sections and
1893 <code>.htaccess</code> files are read, and after the <directive
1894 type="section" module="core">Files</directive> sections.</p>
1896 <p><directive type="section">Location</directive> sections operate
1897 completely outside the filesystem. This has several consequences.
1898 Most importantly, <directive type="section">Location</directive>
1899 directives should not be used to control access to filesystem
1900 locations. Since several different URLs may map to the same
1901 filesystem location, such access controls may by circumvented.</p>
1903 <note><title>When to use <directive
1904 type="section">Location</directive></title>
1906 <p>Use <directive type="section">Location</directive> to apply
1907 directives to content that lives outside the filesystem. For
1908 content that lives in the filesystem, use <directive
1909 type="section" module="core">Directory</directive> and <directive
1910 type="section" module="core">Files</directive>. An exception is
1911 <code><Location /></code>, which is an easy way to
1912 apply a configuration to the entire server.</p>
1915 <p>For all origin (non-proxy) requests, the URL to be matched is a
1916 URL-path of the form <code>/path/</code>. No scheme, hostname,
1917 port, or query string may be included. For proxy requests, the
1918 URL to be matched is of the form
1919 <code>scheme://servername/path</code>, and you must include the
1922 <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
1923 any single character, and <code>*</code> matches any sequences of
1926 <p><glossary ref="regex">Regular expressions</glossary>
1927 can also be used, with the addition of the
1928 <code>~</code> character. For example:</p>
1931 <Location ~ "/(extra|special)/data">
1934 <p>would match URLs that contained the substring <code>/extra/data</code>
1935 or <code>/special/data</code>. The directive <directive
1936 type="section" module="core">LocationMatch</directive> behaves
1937 identical to the regex version of <directive
1938 type="section">Location</directive>.</p>
1940 <p>The <directive type="section">Location</directive>
1941 functionality is especially useful when combined with the
1942 <directive module="core">SetHandler</directive>
1943 directive. For example, to enable status requests, but allow them
1944 only from browsers at <code>foo.com</code>, you might use:</p>
1947 <Location /status><br />
1949 SetHandler server-status<br />
1950 Order Deny,Allow<br />
1952 Allow from .foo.com<br />
1957 <note><title>Note about / (slash)</title>
1958 <p>The slash character has special meaning depending on where in a
1959 URL it appears. People may be used to its behavior in the filesystem
1960 where multiple adjacent slashes are frequently collapsed to a single
1961 slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
1962 <code>/home/foo</code>). In URL-space this is not necessarily true.
1963 The <directive type="section" module="core">LocationMatch</directive>
1964 directive and the regex version of <directive type="section"
1965 >Location</directive> require you to explicitly specify multiple
1966 slashes if that is your intention.</p>
1968 <p>For example, <code><LocationMatch ^/abc></code> would match
1969 the request URL <code>/abc</code> but not the request URL <code>
1970 //abc</code>. The (non-regex) <directive type="section"
1971 >Location</directive> directive behaves similarly when used for
1972 proxy requests. But when (non-regex) <directive type="section"
1973 >Location</directive> is used for non-proxy requests it will
1974 implicitly match multiple slashes with a single slash. For example,
1975 if you specify <code><Location /abc/def></code> and the
1976 request is to <code>/abc//def</code> then it will match.</p>
1979 <seealso><a href="../sections.html">How <Directory>, <Location>
1980 and <Files> sections work</a> for an explanation of how these
1981 different sections are combined when a request is received</seealso>
1982 </directivesynopsis>
1984 <directivesynopsis type="section">
1985 <name>LocationMatch</name>
1986 <description>Applies the enclosed directives only to regular-expression
1987 matching URLs</description>
1988 <syntax><LocationMatch
1989 <var>regex</var>> ... </LocationMatch></syntax>
1990 <contextlist><context>server config</context><context>virtual host</context>
1994 <p>The <directive type="section">LocationMatch</directive> directive
1995 limits the scope of the enclosed directives by URL, in an identical manner
1996 to <directive module="core" type="section">Location</directive>. However,
1997 it takes a <glossary ref="regex">regular expression</glossary>
1998 as an argument instead of a simple string. For example:</p>
2001 <LocationMatch "/(extra|special)/data">
2004 <p>would match URLs that contained the substring <code>/extra/data</code>
2005 or <code>/special/data</code>.</p>
2008 <seealso><a href="../sections.html">How <Directory>, <Location>
2009 and <Files> sections work</a> for an explanation of how these
2010 different sections are combined when a request is received</seealso>
2011 </directivesynopsis>
2014 <name>LogLevel</name>
2015 <description>Controls the verbosity of the ErrorLog</description>
2016 <syntax>LogLevel <var>level</var></syntax>
2017 <default>LogLevel warn</default>
2018 <contextlist><context>server config</context><context>virtual host</context>
2022 <p><directive>LogLevel</directive> adjusts the verbosity of the
2023 messages recorded in the error logs (see <directive
2024 module="core">ErrorLog</directive> directive). The following
2025 <var>level</var>s are available, in order of decreasing
2029 <columnspec><column width=".2"/><column width=".3"/><column width=".5"/>
2032 <th><strong>Level</strong> </th>
2034 <th><strong>Description</strong> </th>
2036 <th><strong>Example</strong> </th>
2040 <td><code>emerg</code> </td>
2042 <td>Emergencies - system is unusable.</td>
2044 <td>"Child cannot open lock file. Exiting"</td>
2048 <td><code>alert</code> </td>
2050 <td>Action must be taken immediately.</td>
2052 <td>"getpwuid: couldn't determine user name from uid"</td>
2056 <td><code>crit</code> </td>
2058 <td>Critical Conditions.</td>
2060 <td>"socket: Failed to get a socket, exiting child"</td>
2064 <td><code>error</code> </td>
2066 <td>Error conditions.</td>
2068 <td>"Premature end of script headers"</td>
2072 <td><code>warn</code> </td>
2074 <td>Warning conditions.</td>
2076 <td>"child process 1234 did not exit, sending another
2081 <td><code>notice</code> </td>
2083 <td>Normal but significant condition.</td>
2085 <td>"httpd: caught SIGBUS, attempting to dump core in
2090 <td><code>info</code> </td>
2092 <td>Informational.</td>
2094 <td>"Server seems busy, (you may need to increase
2095 StartServers, or Min/MaxSpareServers)..."</td>
2099 <td><code>debug</code> </td>
2101 <td>Debug-level messages</td>
2103 <td>"Opening config file ..."</td>
2107 <p>When a particular level is specified, messages from all
2108 other levels of higher significance will be reported as well.
2109 <em>E.g.</em>, when <code>LogLevel info</code> is specified,
2110 then messages with log levels of <code>notice</code> and
2111 <code>warn</code> will also be posted.</p>
2113 <p>Using a level of at least <code>crit</code> is
2122 <note><title>Note</title>
2123 <p>When logging to a regular file messages of the level
2124 <code>notice</code> cannot be suppressed and thus are always
2125 logged. However, this doesn't apply when logging is done
2126 using <code>syslog</code>.</p>
2129 </directivesynopsis>
2132 <name>MaxKeepAliveRequests</name>
2133 <description>Number of requests allowed on a persistent
2134 connection</description>
2135 <syntax>MaxKeepAliveRequests <var>number</var></syntax>
2136 <default>MaxKeepAliveRequests 100</default>
2137 <contextlist><context>server config</context><context>virtual host</context>
2141 <p>The <directive>MaxKeepAliveRequests</directive> directive
2142 limits the number of requests allowed per connection when
2143 <directive module="core" >KeepAlive</directive> is on. If it is
2144 set to <code>0</code>, unlimited requests will be allowed. We
2145 recommend that this setting be kept to a high value for maximum
2146 server performance.</p>
2151 MaxKeepAliveRequests 500
2154 </directivesynopsis>
2157 <name>NameVirtualHost</name>
2158 <description>Designates an IP address for name-virtual
2159 hosting</description>
2160 <syntax>NameVirtualHost <var>addr</var>[:<var>port</var>]</syntax>
2161 <contextlist><context>server config</context></contextlist>
2164 <p>The <directive>NameVirtualHost</directive> directive is a
2165 required directive if you want to configure <a
2166 href="../vhosts/">name-based virtual hosts</a>.</p>
2168 <p>Although <var>addr</var> can be hostname it is recommended
2169 that you always use an IP address, e.g.</p>
2172 NameVirtualHost 111.22.33.44
2175 <p>With the <directive>NameVirtualHost</directive> directive you
2176 specify the IP address on which the server will receive requests
2177 for the name-based virtual hosts. This will usually be the address
2178 to which your name-based virtual host names resolve. In cases
2179 where a firewall or other proxy receives the requests and forwards
2180 them on a different IP address to the server, you must specify the
2181 IP address of the physical interface on the machine which will be
2182 servicing the requests. If you have multiple name-based hosts on
2183 multiple addresses, repeat the directive for each address.</p>
2185 <note><title>Note</title>
2186 <p>Note, that the "main server" and any <code>_default_</code> servers
2187 will <strong>never</strong> be served for a request to a
2188 <directive>NameVirtualHost</directive> IP address (unless for some
2189 reason you specify <directive>NameVirtualHost</directive> but then
2190 don't define any <directive>VirtualHost</directive>s for that
2194 <p>Optionally you can specify a port number on which the
2195 name-based virtual hosts should be used, e.g.</p>
2198 NameVirtualHost 111.22.33.44:8080
2201 <p>IPv6 addresses must be enclosed in square brackets, as shown
2202 in the following example:</p>
2205 NameVirtualHost [2001:db8::a00:20ff:fea7:ccea]:8080
2208 <p>To receive requests on all interfaces, you can use an argument of
2215 <note><title>Argument to <directive type="section">VirtualHost</directive>
2217 <p>Note that the argument to the <directive
2218 type="section">VirtualHost</directive> directive must
2219 exactly match the argument to the <directive
2220 >NameVirtualHost</directive> directive.</p>
2223 NameVirtualHost 1.2.3.4<br />
2224 <VirtualHost 1.2.3.4><br />
2226 </VirtualHost><br />
2231 <seealso><a href="../vhosts/">Virtual Hosts
2232 documentation</a></seealso>
2234 </directivesynopsis>
2237 <name>Options</name>
2238 <description>Configures what features are available in a particular
2239 directory</description>
2241 [+|-]<var>option</var> [[+|-]<var>option</var>] ...</syntax>
2242 <default>Options All</default>
2243 <contextlist><context>server config</context><context>virtual host</context>
2244 <context>directory</context><context>.htaccess</context>
2246 <override>Options</override>
2249 <p>The <directive>Options</directive> directive controls which
2250 server features are available in a particular directory.</p>
2252 <p><var>option</var> can be set to <code>None</code>, in which
2253 case none of the extra features are enabled, or one or more of
2257 <dt><code>All</code></dt>
2259 <dd>All options except for <code>MultiViews</code>. This is the default
2262 <dt><code>ExecCGI</code></dt>
2265 Execution of CGI scripts using <module>mod_cgi</module>
2268 <dt><code>FollowSymLinks</code></dt>
2272 The server will follow symbolic links in this directory.
2274 <p>Even though the server follows the symlink it does <em>not</em>
2275 change the pathname used to match against <directive type="section"
2276 module="core">Directory</directive> sections.</p>
2277 <p>Note also, that this option <strong>gets ignored</strong> if set
2278 inside a <directive type="section" module="core">Location</directive>
2282 <dt><code>Includes</code></dt>
2285 Server-side includes provided by <module>mod_include</module>
2288 <dt><code>IncludesNOEXEC</code></dt>
2292 Server-side includes are permitted, but the <code>#exec
2293 cmd</code> and <code>#exec cgi</code> are disabled. It is still
2294 possible to <code>#include virtual</code> CGI scripts from
2295 <directive module="mod_alias">ScriptAlias</directive>ed
2298 <dt><code>Indexes</code></dt>
2301 If a URL which maps to a directory is requested, and there
2302 is no <directive module="mod_dir">DirectoryIndex</directive>
2303 (<em>e.g.</em>, <code>index.html</code>) in that directory, then
2304 <module>mod_autoindex</module> will return a formatted listing
2305 of the directory.</dd>
2307 <dt><code>MultiViews</code></dt>
2310 <a href="../content-negotiation.html">Content negotiated</a>
2311 "MultiViews" are allowed using
2312 <module>mod_negotiation</module>.</dd>
2314 <dt><code>SymLinksIfOwnerMatch</code></dt>
2316 <dd>The server will only follow symbolic links for which the
2317 target file or directory is owned by the same user id as the
2320 <note><title>Note</title> This option gets ignored if
2321 set inside a <directive module="core"
2322 type="section">Location</directive> section.</note>
2326 <p>Normally, if multiple <directive>Options</directive> could
2327 apply to a directory, then the most specific one is used and
2328 others are ignored; the options are not merged. (See <a
2329 href="../sections.html#mergin">how sections are merged</a>.)
2330 However if <em>all</em> the options on the
2331 <directive>Options</directive> directive are preceded by a
2332 <code>+</code> or <code>-</code> symbol, the options are
2333 merged. Any options preceded by a <code>+</code> are added to the
2334 options currently in force, and any options preceded by a
2335 <code>-</code> are removed from the options currently in
2338 <note type="warning"><title>Warning</title>
2339 <p>Mixing <directive>Options</directive> with a <code>+</code> or
2340 <code>-</code> with those without is not valid syntax, and is likely
2341 to cause unexpected results.</p>
2344 <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>
2347 <Directory /web/docs><br />
2349 Options Indexes FollowSymLinks<br />
2351 </Directory><br />
2353 <Directory /web/docs/spec><br />
2355 Options Includes<br />
2360 <p>then only <code>Includes</code> will be set for the
2361 <code>/web/docs/spec</code> directory. However if the second
2362 <directive>Options</directive> directive uses the <code>+</code> and
2363 <code>-</code> symbols:</p>
2366 <Directory /web/docs><br />
2368 Options Indexes FollowSymLinks<br />
2370 </Directory><br />
2372 <Directory /web/docs/spec><br />
2374 Options +Includes -Indexes<br />
2379 <p>then the options <code>FollowSymLinks</code> and
2380 <code>Includes</code> are set for the <code>/web/docs/spec</code>
2383 <note><title>Note</title>
2384 <p>Using <code>-IncludesNOEXEC</code> or
2385 <code>-Includes</code> disables server-side includes completely
2386 regardless of the previous setting.</p>
2389 <p>The default in the absence of any other settings is
2390 <code>All</code>.</p>
2392 </directivesynopsis>
2395 <name>Require</name>
2396 <description>Selects which authenticated users can access
2397 a resource</description>
2398 <syntax>Require <var>entity-name</var> [<var>entity-name</var>] ...</syntax>
2399 <contextlist><context>directory</context><context>.htaccess</context>
2401 <override>AuthConfig</override>
2404 <p>This directive selects which authenticated users can access a
2405 resource. The restrictions are processed by authorization
2406 modules. Some of the allowed syntaxes provided by
2407 <module>mod_authz_user</module> and
2408 <module>mod_authz_groupfile</module> are:</p>
2411 <dt><code>Require user <var>userid</var> [<var>userid</var>]
2413 <dd>Only the named users can access the resource.</dd>
2415 <dt><code>Require group <var>group-name</var> [<var>group-name</var>]
2417 <dd>Only users in the named groups can access the resource.</dd>
2419 <dt><code>Require valid-user</code></dt>
2420 <dd>All valid users can access the resource.</dd>
2423 <p>Other authorization modules that implement require options
2424 include <module>mod_authnz_ldap</module>,
2425 <module>mod_authz_dbm</module>, and
2426 <module>mod_authz_owner</module>.</p>
2428 <p><directive>Require</directive> must be accompanied by
2429 <directive module="core">AuthName</directive> and <directive
2430 module="core">AuthType</directive> directives, and directives such
2431 as <directive module="mod_authn_file">AuthUserFile</directive>
2432 and <directive module="mod_authz_groupfile">AuthGroupFile</directive> (to
2433 define users and groups) in order to work correctly. Example:</p>
2436 AuthType Basic<br />
2437 AuthName "Restricted Resource"<br />
2438 AuthUserFile /web/users<br />
2439 AuthGroupFile /web/groups<br />
2443 <p>Access controls which are applied in this way are effective for
2444 <strong>all</strong> methods. <strong>This is what is normally
2445 desired.</strong> If you wish to apply access controls only to
2446 specific methods, while leaving other methods unprotected, then
2447 place the <directive>Require</directive> statement into a
2448 <directive module="core" type="section">Limit</directive>
2451 <p>If <directive>Require</directive> is used together with
2452 the <directive module="mod_authz_host">Allow</directive> or
2453 <directive module="mod_authz_host">Deny</directive> directives,
2454 then the interaction of these restrictions is controlled by
2455 the <directive module="core">Satisfy</directive> directive.</p>
2457 <note><title>Removing controls in subdirectories</title>
2458 <p>The following example shows how to use the <directive
2459 module="core">Satisfy</directive> directive to disable access
2460 controls in a subdirectory of a protected directory. This
2461 technique should be used with caution, because it will also
2462 disable any access controls imposed by
2463 <module>mod_authz_host</module>.</p>
2465 <Directory /path/to/protected/><br />
2467 Require user david<br />
2469 </Directory><br />
2470 <Directory /path/to/protected/unprotected><br />
2472 # All access controls and authentication are disabled<br />
2473 # in this directory<br />
2475 Allow from all<br />
2477 </Directory><br />
2483 <seealso><a href="../howto/auth.html">Authentication, Authorization,
2484 and Access Control</a></seealso>
2485 <seealso><directive module="core">Satisfy</directive></seealso>
2486 <seealso><module>mod_authz_host</module></seealso>
2487 </directivesynopsis>
2490 <name>RLimitCPU</name>
2491 <description>Limits the CPU consumption of processes launched
2492 by Apache children</description>
2493 <syntax>RLimitCPU <var>seconds</var>|max [<var>seconds</var>|max]</syntax>
2494 <default>Unset; uses operating system defaults</default>
2495 <contextlist><context>server config</context><context>virtual host</context>
2496 <context>directory</context><context>.htaccess</context></contextlist>
2497 <override>All</override>
2500 <p>Takes 1 or 2 parameters. The first parameter sets the soft
2501 resource limit for all processes and the second parameter sets
2502 the maximum resource limit. Either parameter can be a number,
2503 or <code>max</code> to indicate to the server that the limit should
2504 be set to the maximum allowed by the operating system
2505 configuration. Raising the maximum resource limit requires that
2506 the server is running as <code>root</code>, or in the initial startup
2509 <p>This applies to processes forked off from Apache children
2510 servicing requests, not the Apache children themselves. This
2511 includes CGI scripts and SSI exec commands, but not any
2512 processes forked off from the Apache parent such as piped
2515 <p>CPU resource limits are expressed in seconds per
2518 <seealso><directive module="core">RLimitMEM</directive></seealso>
2519 <seealso><directive module="core">RLimitNPROC</directive></seealso>
2520 </directivesynopsis>
2523 <name>RLimitMEM</name>
2524 <description>Limits the memory consumption of processes launched
2525 by Apache children</description>
2526 <syntax>RLimitMEM <var>bytes</var>|max [<var>bytes</var>|max]</syntax>
2527 <default>Unset; uses operating system defaults</default>
2528 <contextlist><context>server config</context><context>virtual host</context>
2529 <context>directory</context><context>.htaccess</context></contextlist>
2530 <override>All</override>
2533 <p>Takes 1 or 2 parameters. The first parameter sets the soft
2534 resource limit for all processes and the second parameter sets
2535 the maximum resource limit. Either parameter can be a number,
2536 or <code>max</code> to indicate to the server that the limit should
2537 be set to the maximum allowed by the operating system
2538 configuration. Raising the maximum resource limit requires that
2539 the server is running as <code>root</code>, or in the initial startup
2542 <p>This applies to processes forked off from Apache children
2543 servicing requests, not the Apache children themselves. This
2544 includes CGI scripts and SSI exec commands, but not any
2545 processes forked off from the Apache parent such as piped
2548 <p>Memory resource limits are expressed in bytes per
2551 <seealso><directive module="core">RLimitCPU</directive></seealso>
2552 <seealso><directive module="core">RLimitNPROC</directive></seealso>
2553 </directivesynopsis>
2556 <name>RLimitNPROC</name>
2557 <description>Limits the number of processes that can be launched by
2558 processes launched by Apache children</description>
2559 <syntax>RLimitNPROC <var>number</var>|max [<var>number</var>|max]</syntax>
2560 <default>Unset; uses operating system defaults</default>
2561 <contextlist><context>server config</context><context>virtual host</context>
2562 <context>directory</context><context>.htaccess</context></contextlist>
2563 <override>All</override>
2566 <p>Takes 1 or 2 parameters. The first parameter sets the soft
2567 resource limit for all processes and the second parameter sets
2568 the maximum resource limit. Either parameter can be a number,
2569 or <code>max</code> to indicate to the server that the limit
2570 should be set to the maximum allowed by the operating system
2571 configuration. Raising the maximum resource limit requires that
2572 the server is running as <code>root</code>, or in the initial startup
2575 <p>This applies to processes forked off from Apache children
2576 servicing requests, not the Apache children themselves. This
2577 includes CGI scripts and SSI exec commands, but not any
2578 processes forked off from the Apache parent such as piped
2581 <p>Process limits control the number of processes per user.</p>
2583 <note><title>Note</title>
2584 <p>If CGI processes are <strong>not</strong> running
2585 under user ids other than the web server user id, this directive
2586 will limit the number of processes that the server itself can
2587 create. Evidence of this situation will be indicated by
2588 <strong><code>cannot fork</code></strong> messages in the
2589 <code>error_log</code>.</p>
2592 <seealso><directive module="core">RLimitMEM</directive></seealso>
2593 <seealso><directive module="core">RLimitCPU</directive></seealso>
2594 </directivesynopsis>
2597 <name>Satisfy</name>
2598 <description>Interaction between host-level access control and
2599 user authentication</description>
2600 <syntax>Satisfy Any|All</syntax>
2601 <default>Satisfy All</default>
2602 <contextlist><context>directory</context><context>.htaccess</context>
2604 <override>AuthConfig</override>
2605 <compatibility>Influenced by <directive module="core" type="section"
2606 >Limit</directive> and <directive module="core"
2607 type="section">LimitExcept</directive> in version 2.0.51 and
2608 later</compatibility>
2611 <p>Access policy if both <directive
2612 module="mod_authz_host">Allow</directive> and <directive
2613 module="core">Require</directive> used. The parameter can be
2614 either <code>All</code> or <code>Any</code>. This directive is only
2615 useful if access to a particular area is being restricted by both
2616 username/password <em>and</em> client host address. In this case
2617 the default behavior (<code>All</code>) is to require that the client
2618 passes the address access restriction <em>and</em> enters a valid
2619 username and password. With the <code>Any</code> option the client will be
2620 granted access if they either pass the host restriction or enter a
2621 valid username and password. This can be used to password restrict
2622 an area, but to let clients from particular addresses in without
2623 prompting for a password.</p>
2625 <p>For example, if you wanted to let people on your network have
2626 unrestricted access to a portion of your website, but require that
2627 people outside of your network provide a password, you could use a
2628 configuration similar to the following:</p>
2631 Require valid-user<br />
2632 Allow from 192.168.1<br />
2636 <p>Since version 2.0.51 <directive>Satisfy</directive> directives can
2637 be restricted to particular methods by <directive module="core"
2638 type="section">Limit</directive> and <directive module="core" type="section"
2639 >LimitExcept</directive> sections.</p>
2641 <seealso><directive module="mod_authz_host">Allow</directive></seealso>
2642 <seealso><directive module="core">Require</directive></seealso>
2643 </directivesynopsis>
2646 <name>ScriptInterpreterSource</name>
2647 <description>Technique for locating the interpreter for CGI
2648 scripts</description>
2649 <syntax>ScriptInterpreterSource Registry|Registry-Strict|Script</syntax>
2650 <default>ScriptInterpreterSource Script</default>
2651 <contextlist><context>server config</context><context>virtual host</context>
2652 <context>directory</context><context>.htaccess</context></contextlist>
2653 <override>FileInfo</override>
2654 <compatibility>Win32 only;
2655 option <code>Registry-Strict</code> is available in Apache 2.0 and
2656 later</compatibility>
2659 <p>This directive is used to control how Apache finds the
2660 interpreter used to run CGI scripts. The default setting is
2661 <code>Script</code>. This causes Apache to use the interpreter pointed to
2662 by the shebang line (first line, starting with <code>#!</code>) in the
2663 script. On Win32 systems this line usually looks like:</p>
2666 #!C:/Perl/bin/perl.exe
2669 <p>or, if <code>perl</code> is in the <code>PATH</code>, simply:</p>
2675 <p>Setting <code>ScriptInterpreterSource Registry</code> will
2676 cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
2677 searched using the script file extension (e.g., <code>.pl</code>) as a
2678 search key. The command defined by the registry subkey
2679 <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
2680 <code>Shell\Open\Command</code> is used to open the script file. If the
2681 registry keys cannot be found, Apache falls back to the behavior of the
2682 <code>Script</code> option.</p>
2684 <note type="warning"><title>Security</title>
2685 <p>Be careful when using <code>ScriptInterpreterSource
2686 Registry</code> with <directive
2687 module="mod_alias">ScriptAlias</directive>'ed directories, because
2688 Apache will try to execute <strong>every</strong> file within this
2689 directory. The <code>Registry</code> setting may cause undesired
2690 program calls on files which are typically not executed. For
2691 example, the default open command on <code>.htm</code> files on
2692 most Windows systems will execute Microsoft Internet Explorer, so
2693 any HTTP request for an <code>.htm</code> file existing within the
2694 script directory would start the browser in the background on the
2695 server. This is a good way to crash your system within a minute or
2699 <p>The option <code>Registry-Strict</code> which is new in Apache
2700 2.0 does the same thing as <code>Registry</code> but uses only the
2701 subkey <code>Shell\ExecCGI\Command</code>. The
2702 <code>ExecCGI</code> key is not a common one. It must be
2703 configured manually in the windows registry and hence prevents
2704 accidental program calls on your system.</p>
2706 </directivesynopsis>
2709 <name>ServerAdmin</name>
2710 <description>Email address that the server includes in error
2711 messages sent to the client</description>
2712 <syntax>ServerAdmin <var>email-address</var>|<var>URL</var></syntax>
2713 <contextlist><context>server config</context><context>virtual host</context>
2717 <p>The <directive>ServerAdmin</directive> sets the contact address
2718 that the server includes in any error messages it returns to the
2719 client. If the <code>httpd</code> doesn't recognize the supplied argument
2721 assumes, that it's an <var>email-address</var> and prepends it with
2722 <code>mailto:</code> in hyperlink targets. However, it's recommended to
2723 actually use an email address, since there are a lot of CGI scripts that
2724 make that assumption. If you want to use an URL, it should point to another
2725 server under your control. Otherwise users may not be able to contact you in
2728 <p>It may be worth setting up a dedicated address for this, e.g.</p>
2731 ServerAdmin www-admin@foo.example.com
2733 <p>as users do not always mention that they are talking about the
2736 </directivesynopsis>
2739 <name>ServerAlias</name>
2740 <description>Alternate names for a host used when matching requests
2741 to name-virtual hosts</description>
2742 <syntax>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</syntax>
2743 <contextlist><context>virtual host</context></contextlist>
2746 <p>The <directive>ServerAlias</directive> directive sets the
2747 alternate names for a host, for use with <a
2748 href="../vhosts/name-based.html">name-based virtual hosts</a>.</p>
2751 <VirtualHost *><br />
2752 ServerName server.domain.com<br />
2753 ServerAlias server server2.domain.com server2<br />
2755 </VirtualHost>
2758 <seealso><a href="../vhosts/">Apache Virtual Host documentation</a></seealso>
2759 </directivesynopsis>
2762 <name>ServerName</name>
2763 <description>Hostname and port that the server uses to identify
2764 itself</description>
2765 <syntax>ServerName <var>fully-qualified-domain-name</var>[:<var>port</var>]</syntax>
2766 <contextlist><context>server config</context><context>virtual host</context>
2768 <compatibility>In version 2.0, this
2769 directive supersedes the functionality of the <directive>Port</directive>
2770 directive from version 1.3.</compatibility>
2773 <p>The <directive>ServerName</directive> directive sets the hostname and
2774 port that the server uses to identify itself. This is used when
2775 creating redirection URLs. For example, if the name of the
2776 machine hosting the web server is <code>simple.example.com</code>,
2777 but the machine also has the DNS alias <code>www.example.com</code>
2778 and you wish the web server to be so identified, the following
2779 directive should be used:</p>
2782 ServerName www.example.com:80
2785 <p>If no <directive>ServerName</directive> is specified, then the
2786 server attempts to deduce the hostname by performing a reverse
2787 lookup on the IP address. If no port is specified in the
2788 <directive>ServerName</directive>, then the server will use the port
2790 request. For optimal reliability and predictability, you should
2791 specify an explicit hostname and port using the
2792 <directive>ServerName</directive> directive.</p>
2794 <p>If you are using <a
2795 href="../vhosts/name-based.html">name-based virtual hosts</a>,
2796 the <directive>ServerName</directive> inside a
2797 <directive type="section" module="core">VirtualHost</directive>
2798 section specifies what hostname must appear in the request's
2799 <code>Host:</code> header to match this virtual host.</p>
2801 <p>See the description of the
2802 <directive module="core">UseCanonicalName</directive> and
2803 <directive module="core">UseCanonicalPhysicalPort</directive>directives for
2804 settings which determine whether self-referential URL's (e.g., by the
2805 <module>mod_dir</module> module) will refer to the
2806 specified port, or to the port number given in the client's request.
2810 <seealso><a href="../dns-caveats.html">Issues Regarding DNS and
2811 Apache</a></seealso>
2812 <seealso><a href="../vhosts/">Apache virtual host
2813 documentation</a></seealso>
2814 <seealso><directive module="core">UseCanonicalName</directive></seealso>
2815 <seealso><directive module="core">UseCanonicalPhysicalPort</directive></seealso>
2816 <seealso><directive module="core">NameVirtualHost</directive></seealso>
2817 <seealso><directive module="core">ServerAlias</directive></seealso>
2818 </directivesynopsis>
2821 <name>ServerPath</name>
2822 <description>Legacy URL pathname for a name-based virtual host that
2823 is accessed by an incompatible browser</description>
2824 <syntax>ServerPath <var>URL-path</var></syntax>
2825 <contextlist><context>virtual host</context></contextlist>
2828 <p>The <directive>ServerPath</directive> directive sets the legacy
2829 URL pathname for a host, for use with <a
2830 href="../vhosts/">name-based virtual hosts</a>.</p>
2832 <seealso><a href="../vhosts/">Apache Virtual Host documentation</a></seealso>
2833 </directivesynopsis>
2836 <name>ServerRoot</name>
2837 <description>Base directory for the server installation</description>
2838 <syntax>ServerRoot <var>directory-path</var></syntax>
2839 <default>ServerRoot /usr/local/apache</default>
2840 <contextlist><context>server config</context></contextlist>
2843 <p>The <directive>ServerRoot</directive> directive sets the
2844 directory in which the server lives. Typically it will contain the
2845 subdirectories <code>conf/</code> and <code>logs/</code>. Relative
2846 paths in other configuration directives (such as <directive
2847 module="core">Include</directive> or <directive
2848 module="mod_so">LoadModule</directive>, for example) are taken as
2849 relative to this directory.</p>
2851 <example><title>Example</title>
2852 ServerRoot /home/httpd
2856 <seealso><a href="../invoking.html">the <code>-d</code>
2857 option to <code>httpd</code></a></seealso>
2858 <seealso><a href="../misc/security_tips.html#serverroot">the
2859 security tips</a> for information on how to properly set
2860 permissions on the <directive>ServerRoot</directive></seealso>
2861 </directivesynopsis>
2864 <name>ServerSignature</name>
2865 <description>Configures the footer on server-generated documents</description>
2866 <syntax>ServerSignature On|Off|EMail</syntax>
2867 <default>ServerSignature Off</default>
2868 <contextlist><context>server config</context><context>virtual host</context>
2869 <context>directory</context><context>.htaccess</context>
2871 <override>All</override>
2874 <p>The <directive>ServerSignature</directive> directive allows the
2875 configuration of a trailing footer line under server-generated
2876 documents (error messages, <module>mod_proxy</module> ftp directory
2877 listings, <module>mod_info</module> output, ...). The reason why you
2878 would want to enable such a footer line is that in a chain of proxies,
2879 the user often has no possibility to tell which of the chained servers
2880 actually produced a returned error message.</p>
2882 <p>The <code>Off</code>
2883 setting, which is the default, suppresses the footer line (and is
2884 therefore compatible with the behavior of Apache-1.2 and
2885 below). The <code>On</code> setting simply adds a line with the
2886 server version number and <directive
2887 module="core">ServerName</directive> of the serving virtual host,
2888 and the <code>EMail</code> setting additionally creates a
2889 "mailto:" reference to the <directive
2890 module="core">ServerAdmin</directive> of the referenced
2893 <p>After version 2.0.44, the details of the server version number
2894 presented are controlled by the <directive
2895 module="core">ServerTokens</directive> directive.</p>
2897 <seealso><directive module="core">ServerTokens</directive></seealso>
2898 </directivesynopsis>
2901 <name>ServerTokens</name>
2902 <description>Configures the <code>Server</code> HTTP response
2903 header</description>
2904 <syntax>ServerTokens Major|Minor|Min[imal]|Prod[uctOnly]|OS|Full</syntax>
2905 <default>ServerTokens Full</default>
2906 <contextlist><context>server config</context></contextlist>
2909 <p>This directive controls whether <code>Server</code> response
2910 header field which is sent back to clients includes a
2911 description of the generic OS-type of the server as well as
2912 information about compiled-in modules.</p>
2915 <dt><code>ServerTokens Prod[uctOnly]</code></dt>
2917 <dd>Server sends (<em>e.g.</em>): <code>Server:
2920 <dt><code>ServerTokens Major</code></dt>
2922 <dd>Server sends (<em>e.g.</em>): <code>Server:
2923 Apache/2</code></dd>
2925 <dt><code>ServerTokens Minor</code></dt>
2927 <dd>Server sends (<em>e.g.</em>): <code>Server:
2928 Apache/2.0</code></dd>
2930 <dt><code>ServerTokens Min[imal]</code></dt>
2932 <dd>Server sends (<em>e.g.</em>): <code>Server:
2933 Apache/2.0.41</code></dd>
2935 <dt><code>ServerTokens OS</code></dt>
2937 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.0.41
2940 <dt><code>ServerTokens Full</code> (or not specified)</dt>
2942 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.0.41
2943 (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
2946 <p>This setting applies to the entire server, and cannot be
2947 enabled or disabled on a virtualhost-by-virtualhost basis.</p>
2949 <p>After version 2.0.44, this directive also controls the
2950 information presented by the <directive
2951 module="core">ServerSignature</directive> directive.</p>
2953 <seealso><directive module="core">ServerSignature</directive></seealso>
2954 </directivesynopsis>
2957 <name>SetHandler</name>
2958 <description>Forces all matching files to be processed by a
2959 handler</description>
2960 <syntax>SetHandler <var>handler-name</var>|None</syntax>
2961 <contextlist><context>server config</context><context>virtual host</context>
2962 <context>directory</context><context>.htaccess</context>
2964 <override>FileInfo</override>
2965 <compatibility>Moved into the core in Apache 2.0</compatibility>
2968 <p>When placed into an <code>.htaccess</code> file or a
2969 <directive type="section" module="core">Directory</directive> or
2970 <directive type="section" module="core">Location</directive>
2971 section, this directive forces all matching files to be parsed
2972 through the <a href="../handler.html">handler</a> given by
2973 <var>handler-name</var>. For example, if you had a directory you
2974 wanted to be parsed entirely as imagemap rule files, regardless
2975 of extension, you might put the following into an
2976 <code>.htaccess</code> file in that directory:</p>
2979 SetHandler imap-file
2982 <p>Another example: if you wanted to have the server display a
2983 status report whenever a URL of
2984 <code>http://servername/status</code> was called, you might put
2985 the following into <code>httpd.conf</code>:</p>
2988 <Location /status><br />
2990 SetHandler server-status<br />
2995 <p>You can override an earlier defined <directive>SetHandler</directive>
2996 directive by using the value <code>None</code>.</p>
2997 <p><strong>Note:</strong> because SetHandler overrides default handlers,
2998 normal behaviour such as handling of URLs ending in a slash (/) as
2999 directories or index files is suppressed.</p>
3002 <seealso><directive module="mod_mime">AddHandler</directive></seealso>
3004 </directivesynopsis>
3007 <name>SetInputFilter</name>
3008 <description>Sets the filters that will process client requests and POST
3010 <syntax>SetInputFilter <var>filter</var>[;<var>filter</var>...]</syntax>
3011 <contextlist><context>server config</context><context>virtual host</context>
3012 <context>directory</context><context>.htaccess</context>
3014 <override>FileInfo</override>
3017 <p>The <directive>SetInputFilter</directive> directive sets the
3018 filter or filters which will process client requests and POST
3019 input when they are received by the server. This is in addition to
3020 any filters defined elsewhere, including the
3021 <directive module="mod_mime">AddInputFilter</directive>
3024 <p>If more than one filter is specified, they must be separated
3025 by semicolons in the order in which they should process the
3028 <seealso><a href="../filter.html">Filters</a> documentation</seealso>
3029 </directivesynopsis>
3032 <name>SetOutputFilter</name>
3033 <description>Sets the filters that will process responses from the
3034 server</description>
3035 <syntax>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</syntax>
3036 <contextlist><context>server config</context><context>virtual host</context>
3037 <context>directory</context><context>.htaccess</context>
3039 <override>FileInfo</override>
3042 <p>The <directive>SetOutputFilter</directive> directive sets the filters
3043 which will process responses from the server before they are
3044 sent to the client. This is in addition to any filters defined
3045 elsewhere, including the
3046 <directive module="mod_mime">AddOutputFilter</directive>
3049 <p>For example, the following configuration will process all files
3050 in the <code>/www/data/</code> directory for server-side
3054 <Directory /www/data/><br />
3056 SetOutputFilter INCLUDES<br />
3061 <p>If more than one filter is specified, they must be separated
3062 by semicolons in the order in which they should process the
3065 <seealso><a href="../filter.html">Filters</a> documentation</seealso>
3066 </directivesynopsis>
3069 <name>TimeOut</name>
3070 <description>Amount of time the server will wait for
3071 certain events before failing a request</description>
3072 <syntax>TimeOut <var>seconds</var></syntax>
3073 <default>TimeOut 300</default>
3074 <contextlist><context>server config</context></contextlist>
3077 <p>The <directive>TimeOut</directive> directive currently defines
3078 the amount of time Apache will wait for three things:</p>
3081 <li>The total amount of time it takes to receive a GET
3084 <li>The amount of time between receipt of TCP packets on a
3085 POST or PUT request.</li>
3087 <li>The amount of time between ACKs on transmissions of TCP
3088 packets in responses.</li>
3091 <p>We plan on making these separately configurable at some point
3092 down the road. The timer used to default to 1200 before 1.2,
3093 but has been lowered to 300 which is still far more than
3094 necessary in most situations. It is not set any lower by
3095 default because there may still be odd places in the code where
3096 the timer is not reset when a packet is sent. </p>
3098 </directivesynopsis>
3101 <name>TraceEnable</name>
3102 <description>Determines the behaviour on <code>TRACE</code>
3103 requests</description>
3104 <syntax>TraceEnable <var>[on|off|extended]</var></syntax>
3105 <default>TraceEnable on</default>
3106 <contextlist><context>server config</context></contextlist>
3107 <compatibility>Available in Apache 1.3.34, 2.0.55 and later</compatibility>
3110 <p>This directive overrides the behavior of <code>TRACE</code> for both
3111 the core server and <module>mod_proxy</module>. The default
3112 <code>TraceEnable on</code> permits <code>TRACE</code> requests per
3113 RFC 2616, which disallows any request body to accompany the request.
3114 <code>TraceEnable off</code> causes the core server and
3115 <module>mod_proxy</module> to return a <code>405</code> (Method not
3116 allowed) error to the client.</p>
3118 <p>Finally, for testing and diagnostic purposes only, request
3119 bodies may be allowed using the non-compliant <code>TraceEnable
3120 extended</code> directive. The core (as an origin server) will
3121 restrict the request body to 64k (plus 8k for chunk headers if
3122 <code>Transfer-Encoding: chunked</code> is used). The core will
3123 reflect the full headers and all chunk headers with the response
3124 body. As a proxy server, the request body is not restricted to 64k.</p>
3126 </directivesynopsis>
3129 <name>UseCanonicalName</name>
3130 <description>Configures how the server determines its own name and
3132 <syntax>UseCanonicalName On|Off|DNS</syntax>
3133 <default>UseCanonicalName Off</default>
3134 <contextlist><context>server config</context><context>virtual host</context>
3135 <context>directory</context></contextlist>
3138 <p>In many situations Apache must construct a <em>self-referential</em>
3139 URL -- that is, a URL that refers back to the same server. With
3140 <code>UseCanonicalName On</code> Apache will use the hostname and port
3141 specified in the <directive module="core">ServerName</directive>
3142 directive to construct the canonical name for the server. This name
3143 is used in all self-referential URLs, and for the values of
3144 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>
3146 <p>With <code>UseCanonicalName Off</code> Apache will form
3147 self-referential URLs using the hostname and port supplied by
3148 the client if any are supplied (otherwise it will use the
3149 canonical name, as defined above). These values are the same
3150 that are used to implement <a
3151 href="../vhosts/name-based.html">name based virtual hosts</a>,
3152 and are available with the same clients. The CGI variables
3153 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
3154 constructed from the client supplied values as well.</p>
3156 <p>An example where this may be useful is on an intranet server
3157 where you have users connecting to the machine using short
3158 names such as <code>www</code>. You'll notice that if the users
3159 type a shortname, and a URL which is a directory, such as
3160 <code>http://www/splat</code>, <em>without the trailing
3161 slash</em> then Apache will redirect them to
3162 <code>http://www.domain.com/splat/</code>. If you have
3163 authentication enabled, this will cause the user to have to
3164 authenticate twice (once for <code>www</code> and once again
3165 for <code>www.domain.com</code> -- see <a
3166 href="http://httpd.apache.org/docs/misc/FAQ.html#prompted-twice">the
3167 FAQ on this subject for more information</a>). But if
3168 <directive>UseCanonicalName</directive> is set <code>Off</code>, then
3169 Apache will redirect to <code>http://www/splat/</code>.</p>
3171 <p>There is a third option, <code>UseCanonicalName DNS</code>,
3172 which is intended for use with mass IP-based virtual hosting to
3173 support ancient clients that do not provide a
3174 <code>Host:</code> header. With this option Apache does a
3175 reverse DNS lookup on the server IP address that the client
3176 connected to in order to work out self-referential URLs.</p>
3178 <note type="warning"><title>Warning</title>
3179 <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>
3180 they may be broken by this option. The client is essentially free
3181 to give whatever value they want as a hostname. But if the CGI is
3182 only using <code>SERVER_NAME</code> to construct self-referential URLs
3183 then it should be just fine.</p>
3186 <seealso><directive module="core">UseCanonicalPhysicalPort</directive></seealso>
3187 <seealso><directive module="core">ServerName</directive></seealso>
3188 <seealso><directive module="mpm_common">Listen</directive></seealso>
3189 </directivesynopsis>
3192 <name>UseCanonicalPhysicalPort</name>
3193 <description>Configures how the server determines its own name and
3195 <syntax>UseCanonicalPhysicalPort On|Off</syntax>
3196 <default>UseCanonicalPhysicalPort Off</default>
3197 <contextlist><context>server config</context><context>virtual host</context>
3198 <context>directory</context></contextlist>
3201 <p>In many situations Apache must construct a <em>self-referential</em>
3202 URL -- that is, a URL that refers back to the same server. With
3203 <code>UseCanonicalPhysicalPort On</code> Apache will, when
3204 constructing the canonical port for the server to honor
3205 the <directive module="core">UseCanonicalName</directive> directive,
3206 provide the actual physical port number being used by this request
3207 as a potential port. With <code>UseCanonicalPhysicalPort Off</code>
3208 Apache will not ever use the actual physical port number, instead
3209 relying on all configured information to construct a valid port number.</p>
3211 <note><title>Note</title>
3212 <p>The ordering of when the physical port is used is as follows:<br /><br />
3213 <code>UseCanonicalName On</code></p>
3215 <li>Port provided in <code>Servername</code></li>
3216 <li>Physical port</li>
3217 <li>Default port</li>
3219 <code>UseCanonicalName Off | DNS</code>
3221 <li>Parsed port from <code>Host:</code> header</li>
3222 <li>Physical port</li>
3223 <li>Port provided in <code>Servername</code></li>
3224 <li>Default port</li>
3227 <p>With <code>UseCanonicalPhysicalPort Off</code>, the
3228 physical ports are removed from the ordering.</p>
3232 <seealso><directive module="core">UseCanonicalName</directive></seealso>
3233 <seealso><directive module="core">ServerName</directive></seealso>
3234 <seealso><directive module="mpm_common">Listen</directive></seealso>
3235 </directivesynopsis>
3237 <directivesynopsis type="section">
3238 <name>VirtualHost</name>
3239 <description>Contains directives that apply only to a specific
3240 hostname or IP address</description>
3241 <syntax><VirtualHost
3242 <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
3243 ...> ... </VirtualHost></syntax>
3244 <contextlist><context>server config</context></contextlist>
3247 <p><directive type="section">VirtualHost</directive> and
3248 <code></VirtualHost></code> are used to enclose a group of
3249 directives that will apply only to a particular virtual host. Any
3250 directive that is allowed in a virtual host context may be
3251 used. When the server receives a request for a document on a
3252 particular virtual host, it uses the configuration directives
3253 enclosed in the <directive type="section">VirtualHost</directive>
3254 section. <var>Addr</var> can be:</p>
3257 <li>The IP address of the virtual host;</li>
3259 <li>A fully qualified domain name for the IP address of the
3262 <li>The character <code>*</code>, which is used only in combination with
3263 <code>NameVirtualHost *</code> to match all IP addresses; or</li>
3265 <li>The string <code>_default_</code>, which is used only
3266 with IP virtual hosting to catch unmatched IP addresses.</li>
3269 <example><title>Example</title>
3270 <VirtualHost 10.1.2.3><br />
3272 ServerAdmin webmaster@host.foo.com<br />
3273 DocumentRoot /www/docs/host.foo.com<br />
3274 ServerName host.foo.com<br />
3275 ErrorLog logs/host.foo.com-error_log<br />
3276 TransferLog logs/host.foo.com-access_log<br />
3278 </VirtualHost>
3282 <p>IPv6 addresses must be specified in square brackets because
3283 the optional port number could not be determined otherwise. An
3284 IPv6 example is shown below:</p>
3287 <VirtualHost [2001:db8::a00:20ff:fea7:ccea]><br />
3289 ServerAdmin webmaster@host.example.com<br />
3290 DocumentRoot /www/docs/host.example.com<br />
3291 ServerName host.example.com<br />
3292 ErrorLog logs/host.example.com-error_log<br />
3293 TransferLog logs/host.example.com-access_log<br />
3295 </VirtualHost>
3298 <p>Each Virtual Host must correspond to a different IP address,
3299 different port number or a different host name for the server,
3300 in the former case the server machine must be configured to
3301 accept IP packets for multiple addresses. (If the machine does
3302 not have multiple network interfaces, then this can be
3303 accomplished with the <code>ifconfig alias</code> command -- if
3304 your OS supports it).</p>
3306 <note><title>Note</title>
3307 <p>The use of <directive type="section">VirtualHost</directive> does
3308 <strong>not</strong> affect what addresses Apache listens on. You
3309 may need to ensure that Apache is listening on the correct addresses
3310 using <directive module="mpm_common">Listen</directive>.</p>
3313 <p>When using IP-based virtual hosting, the special name
3314 <code>_default_</code> can be specified in
3315 which case this virtual host will match any IP address that is
3316 not explicitly listed in another virtual host. In the absence
3317 of any <code>_default_</code> virtual host the "main" server config,
3318 consisting of all those definitions outside any VirtualHost
3319 section, is used when no IP-match occurs. (But note that any IP
3320 address that matches a <directive
3321 module="core">NameVirtualHost</directive> directive will use neither
3322 the "main" server config nor the <code>_default_</code> virtual host.
3323 See the <a href="../vhosts/name-based.html">name-based virtual hosting</a>
3324 documentation for further details.)</p>
3326 <p>You can specify a <code>:port</code> to change the port that is
3327 matched. If unspecified then it defaults to the same port as the
3328 most recent <directive module="mpm_common">Listen</directive>
3329 statement of the main server. You may also specify <code>:*</code>
3330 to match all ports on that address. (This is recommended when used
3331 with <code>_default_</code>.)</p>
3333 <note type="warning"><title>Security</title>
3334 <p>See the <a href="../misc/security_tips.html">security tips</a>
3335 document for details on why your security could be compromised if the
3336 directory where log files are stored is writable by anyone other
3337 than the user that starts the server.</p>
3340 <seealso><a href="../vhosts/">Apache Virtual Host documentation</a></seealso>
3341 <seealso><a href="../dns-caveats.html">Issues Regarding DNS and
3342 Apache</a></seealso>
3343 <seealso><a href="../bind.html">Setting
3344 which addresses and ports Apache uses</a></seealso>
3345 <seealso><a href="../sections.html">How <Directory>, <Location>
3346 and <Files> sections work</a> for an explanation of how these
3347 different sections are combined when a request is received</seealso>
3348 </directivesynopsis>