2 <!DOCTYPE modulesynopsis SYSTEM "../style/modulesynopsis.dtd">
3 <?xml-stylesheet type="text/xsl" href="../style/manual.en.xsl"?>
6 Copyright 2002-2004 The Apache Software Foundation
8 Licensed under the Apache License, Version 2.0 (the "License");
9 you may not use this file except in compliance with the License.
10 You may obtain a copy of the License at
12 http://www.apache.org/licenses/LICENSE-2.0
14 Unless required by applicable law or agreed to in writing, software
15 distributed under the License is distributed on an "AS IS" BASIS,
16 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17 See the License for the specific language governing permissions and
18 limitations under the License.
21 <modulesynopsis metafile="core.xml.meta">
24 <description>Core Apache HTTP Server features that are always
25 available</description>
29 <name>AcceptPathInfo</name>
30 <description>Resources accept trailing pathname information</description>
31 <syntax>AcceptPathInfo On|Off|Default</syntax>
32 <default>AcceptPathInfo Default</default>
33 <contextlist><context>server config</context>
34 <context>virtual host</context><context>directory</context>
35 <context>.htaccess</context></contextlist>
36 <override>FileInfo</override>
37 <compatibility>Available in Apache 2.0.30 and later</compatibility>
41 <p>This directive controls whether requests that contain trailing
42 pathname information that follows an actual filename (or
43 non-existent file in an existing directory) will be accepted or
44 rejected. The trailing pathname information can be made
45 available to scripts in the <code>PATH_INFO</code> environment
48 <p>For example, assume the location <code>/test/</code> points to
49 a directory that contains only the single file
50 <code>here.html</code>. Then requests for
51 <code>/test/here.html/more</code> and
52 <code>/test/nothere.html/more</code> both collect
53 <code>/more</code> as <code>PATH_INFO</code>.</p>
55 <p>The three possible arguments for the
56 <directive>AcceptPathInfo</directive> directive are:</p>
58 <dt><code>Off</code></dt><dd>A request will only be accepted if it
59 maps to a literal path that exists. Therefore a request with
60 trailing pathname information after the true filename such as
61 <code>/test/here.html/more</code> in the above example will return
62 a 404 NOT FOUND error.</dd>
64 <dt><code>On</code></dt><dd>A request will be accepted if a
65 leading path component maps to a file that exists. The above
66 example <code>/test/here.html/more</code> will be accepted if
67 <code>/test/here.html</code> maps to a valid file.</dd>
69 <dt><code>Default</code></dt><dd>The treatment of requests with
70 trailing pathname information is determined by the <a
71 href="../handler.html">handler</a> responsible for the request.
72 The core handler for normal files defaults to rejecting
73 <code>PATH_INFO</code> requests. Handlers that serve scripts, such as <a
74 href="mod_cgi.html">cgi-script</a> and <a
75 href="mod_isapi.html">isapi-isa</a>, generally accept
76 <code>PATH_INFO</code> by default.</dd>
79 <p>The primary purpose of the <code>AcceptPathInfo</code>
80 directive is to allow you to override the handler's choice of
81 accepting or rejecting <code>PATH_INFO</code>. This override is required,
82 for example, when you use a <a href="../filter.html">filter</a>, such
83 as <a href="mod_include.html">INCLUDES</a>, to generate content
84 based on <code>PATH_INFO</code>. The core handler would usually reject
85 the request, so you can use the following configuration to enable
89 <Files "mypaths.shtml"><br />
91 Options +Includes<br />
92 SetOutputFilter INCLUDES<br />
93 AcceptPathInfo On<br />
102 <name>AccessFileName</name>
103 <description>Name of the distributed configuration file</description>
104 <syntax>AccessFileName <var>filename</var> [<var>filename</var>] ...</syntax>
105 <default>AccessFileName .htaccess</default>
106 <contextlist><context>server config</context><context>virtual host</context>
110 <p>While processing a request the server looks for
111 the first existing configuration file from this list of names in
112 every directory of the path to the document, if distributed
113 configuration files are <a href="#allowoverride">enabled for that
114 directory</a>. For example:</p>
120 <p>before returning the document
121 <code>/usr/local/web/index.html</code>, the server will read
122 <code>/.acl</code>, <code>/usr/.acl</code>,
123 <code>/usr/local/.acl</code> and <code>/usr/local/web/.acl</code>
124 for directives, unless they have been disabled with</p>
127 <Directory /><br />
129 AllowOverride None<br />
134 <seealso><directive module="core">AllowOverride</directive></seealso>
135 <seealso><a href="../configuring.html">Configuration Files</a></seealso>
136 <seealso><a href="../howto/htaccess.html">.htaccess Files</a></seealso>
140 <name>AddDefaultCharset</name>
141 <description>Default character set to be added for a
142 response without an explicit character set</description>
143 <syntax>AddDefaultCharset On|Off|<var>charset</var></syntax>
144 <default>AddDefaultCharset Off</default>
145 <contextlist><context>server config</context>
146 <context>virtual host</context><context>directory</context>
147 <context>.htaccess</context></contextlist>
148 <override>FileInfo</override>
151 <p>This directive specifies the name of the character set that
152 will be added to any response that does not have any parameter on
153 the content type in the HTTP headers. This will override any
154 character set specified in the body of the document via a
155 <code>META</code> tag. A setting of <code>AddDefaultCharset
156 Off</code> disables this
157 functionality. <code>AddDefaultCharset On</code> enables
158 Apache's internal default charset of <code>iso-8859-1</code> as
159 required by the directive. You can also specify an alternate
160 <var>charset</var> to be used. For example:</p>
163 AddDefaultCharset utf-8
169 <name>AddOutputFilterByType</name>
170 <description>assigns an output filter to a particular MIME-type</description>
171 <syntax>AddOutputFilterByType <var>filter</var>[;<var>filter</var>...]
172 <var>MIME-type</var> [<var>MIME-type</var>] ...</syntax>
173 <contextlist><context>server config</context>
174 <context>virtual host</context><context>directory</context>
175 <context>.htaccess</context></contextlist>
176 <override>FileInfo</override>
177 <compatibility>Available in Apache 2.0.33 and later</compatibility>
180 <p>This directive activates a particular output <a
181 href="../filter.html">filter</a> for a request depending on the
182 response MIME-type.</p>
184 <p>The following example uses the <code>DEFLATE</code> filter, which
185 is provided by <module>mod_deflate</module>. It will compress all
186 output (either static or dynamic) which is labeled as
187 <code>text/html</code> or <code>text/plain</code> before it is sent
191 AddOutputFilterByType DEFLATE text/html text/plain
194 <p>If you want the content to be processed by more than one filter, their
195 names have to be separated by semicolons. It's also possible to use one
196 <directive>AddOutputFilterByType</directive> directive for each of
199 <p>The configuration below causes all script output labeled as
200 <code>text/html</code> to be processed at first by the
201 <code>INCLUDES</code> filter and then by the <code>DEFLATE</code>
205 <Location /cgi-bin/><br />
207 Options Includes<br />
208 AddOutputFilterByType INCLUDES;DEFLATE text/html<br />
213 <note type="warning"><title>Note</title>
214 <p>Enabling filters with <directive>AddOutputFilterByType</directive>
215 may fail partially or completely in some cases. For expample, no
216 filters are applied if the MIME-type could not be determined and falls
217 back to the <directive module="core">DefaultType</directive> setting,
218 even if the <directive module="core">DefaultType</directive> is the
221 <p>However, if you want to make sure, that the filters will be
222 applied, assign the content type to a resource explicitely, for
223 example with <directive module="mod_mime">AddType</directive> or
224 <directive module="core">ForceType</directive>. Setting the
225 content type within a (non-nph) CGI script is also safe.</p>
227 <p>The by-type output filters are never applied on proxy requests.</p>
231 <seealso><directive module="mod_mime">AddOutputFilter</directive></seealso>
232 <seealso><directive module="core">SetOutputFilter</directive></seealso>
233 <seealso><a href="../filter.html">filters</a></seealso>
237 <name>AllowEncodedSlashes</name>
238 <description>Determines whether encoded path separators in URLs are allowed to
239 be passed through</description>
240 <syntax>AllowEncodedSlashes On|Off</syntax>
241 <default>AllowEncodedSlashes Off</default>
242 <contextlist><context>server config</context><context>virtual host</context>
244 <compatibility>Available in Apache 2.0.46 and later</compatibility>
247 <p>The <directive>AllowEncodedSlashes</directive> directive allows URLs
248 which contain encoded path separators (<code>%2F</code> for <code>/</code>
249 and additionally <code>%5C</code> for <code>\</code> on according systems)
250 to be used. Normally such URLs are refused with a 404 (Not found) error.</p>
252 <p>Turning <directive>AllowEncodedSlashes</directive> <code>On</code> is
253 mostly useful when used in conjunction with <code>PATH_INFO</code>.</p>
255 <note><title>Note</title>
256 <p>Allowing encoded slashes does <em>not</em> imply <em>decoding</em>.
257 Occurences of <code>%2F</code> or <code>%5C</code> (<em>only</em> on
258 according systems) will be left as such in the otherwise decoded URL
262 <seealso><directive module="core">AcceptPathInfo</directive></seealso>
267 <name>AllowOverride</name>
268 <description>Types of directives that are allowed in
269 <code>.htaccess</code> files</description>
270 <syntax>AllowOverride All|None|<var>directive-type</var>
271 [<var>directive-type</var>] ...</syntax>
272 <default>AllowOverride All</default>
273 <contextlist><context>directory</context></contextlist>
276 <p>When the server finds an <code>.htaccess</code> file (as
277 specified by <directive module="core">AccessFileName</directive>)
278 it needs to know which directives declared in that file can override
279 earlier configuration directives.</p>
281 <note><title>Only available in <Directory> sections</title>
282 <directive>AllowOverride</directive> is valid only in
283 <directive type="section" module="core">Directory</directive>
284 sections, not in <directive type="section"
285 module="core">Location</directive> or <directive type="section"
286 module="core">Files</directive> sections.
289 <p>When this directive is set to <code>None</code>, then
290 <a href="#accessfilename">.htaccess</a> files are completely ignored.
291 In this case, the server will not even attempt to read
292 <code>.htaccess</code> files in the filesystem.</p>
294 <p>When this directive is set to <code>All</code>, then any
295 directive which has the .htaccess <a
296 href="directive-dict.html#Context">Context</a> is allowed in
297 <code>.htaccess</code> files.</p>
299 <p>The <var>directive-type</var> can be one of the following
300 groupings of directives.</p>
307 Allow use of the authorization directives (<directive
308 module="mod_authn_dbm">AuthDBMGroupFile</directive>,
309 <directive module="mod_authn_dbm">AuthDBMUserFile</directive>,
310 <directive module="mod_authz_groupfile">AuthGroupFile</directive>,
311 <directive module="core">AuthName</directive>,
312 <directive module="core">AuthType</directive>, <directive
313 module="mod_authn_file">AuthUserFile</directive>, <directive
314 module="core">Require</directive>, <em>etc.</em>).</dd>
319 Allow use of the directives controlling document types (<directive
320 module="core">DefaultType</directive>, <directive
321 module="core">ErrorDocument</directive>, <directive
322 module="core">ForceType</directive>, <directive
323 module="mod_negotiation">LanguagePriority</directive>,
324 <directive module="core">SetHandler</directive>, <directive
325 module="core">SetInputFilter</directive>, <directive
326 module="core">SetOutputFilter</directive>, and
327 <module>mod_mime</module> Add* and Remove*
328 directives, <em>etc.</em>).</dd>
333 Allow use of the directives controlling directory indexing
335 module="mod_autoindex">AddDescription</directive>,
336 <directive module="mod_autoindex">AddIcon</directive>, <directive
337 module="mod_autoindex">AddIconByEncoding</directive>,
338 <directive module="mod_autoindex">AddIconByType</directive>,
339 <directive module="mod_autoindex">DefaultIcon</directive>, <directive
340 module="mod_dir">DirectoryIndex</directive>, <directive
341 module="mod_autoindex">FancyIndexing</directive>, <directive
342 module="mod_autoindex">HeaderName</directive>, <directive
343 module="mod_autoindex">IndexIgnore</directive>, <directive
344 module="mod_autoindex">IndexOptions</directive>, <directive
345 module="mod_autoindex">ReadmeName</directive>,
351 Allow use of the directives controlling host access (<directive
352 module="mod_authz_host">Allow</directive>, <directive
353 module="mod_authz_host">Deny</directive> and <directive
354 module="mod_authz_host">Order</directive>).</dd>
359 Allow use of the directives controlling specific directory
360 features (<directive module="core">Options</directive> and
361 <directive module="mod_include">XBitHack</directive>).</dd>
367 AllowOverride AuthConfig Indexes
371 <seealso><directive module="core">AccessFileName</directive></seealso>
372 <seealso><a href="../configuring.html">Configuration Files</a></seealso>
373 <seealso><a href="../howto/htaccess.html">.htaccess Files</a></seealso>
377 <name>AuthName</name>
378 <description>Authorization realm for use in HTTP
379 authentication</description>
380 <syntax>AuthName <var>auth-domain</var></syntax>
381 <contextlist><context>directory</context><context>.htaccess</context>
383 <override>AuthConfig</override>
386 <p>This directive sets the name of the authorization realm for a
387 directory. This realm is given to the client so that the user
388 knows which username and password to send.
389 <directive>AuthName</directive> takes a single argument; if the
390 realm name contains spaces, it must be enclosed in quotation
391 marks. It must be accompanied by <directive
392 module="core">AuthType</directive> and <directive
393 module="core">Require</directive> directives, and directives such
394 as <directive module="mod_authn_file">AuthUserFile</directive> and
395 <directive module="mod_authz_groupfile">AuthGroupFile</directive> to
401 AuthName "Top Secret"
404 <p>The string provided for the <code>AuthName</code> is what will
405 appear in the password dialog provided by most browsers.</p>
408 href="../howto/auth.html">Authentication, Authorization, and
409 Access Control</a></seealso>
413 <name>AuthType</name>
414 <description>Type of user authentication</description>
415 <syntax>AuthType Basic|Digest</syntax>
416 <contextlist><context>directory</context><context>.htaccess</context>
418 <override>AuthConfig</override>
421 <p>This directive selects the type of user authentication for a
422 directory. Only <code>Basic</code> and <code>Digest</code> are
423 currently implemented.
425 It must be accompanied by <directive
426 module="core">AuthName</directive> and <directive
427 module="core">Require</directive> directives, and directives such
428 as <directive module="mod_authn_file">AuthUserFile</directive> and
429 <directive module="mod_authz_groupfile">AuthGroupFile</directive> to
432 <seealso><a href="../howto/auth.html">Authentication, Authorization,
433 and Access Control</a></seealso>
437 <name>CGIMapExtension</name>
438 <description>Technique for locating the interpreter for CGI
439 scripts</description>
440 <syntax>CGIMapExtension <var>cgi-path</var> <var>.extension</var></syntax>
441 <contextlist><context>directory</context><context>.htaccess</context>
443 <override>FileInfo</override>
444 <compatibility>NetWare only</compatibility>
447 <p>This directive is used to control how Apache finds the
448 interpreter used to run CGI scripts. For example, setting
449 <code>CGIMapExtension sys:\foo.nlm .foo</code> will
450 cause all CGI script files with a <code>.foo</code> extension to
451 be passed to the FOO interpreter.</p>
456 <name>ContentDigest</name>
457 <description>Enables the generation of <code>Content-MD5</code> HTTP Response
458 headers</description>
459 <syntax>ContentDigest On|Off</syntax>
460 <default>ContentDigest Off</default>
461 <contextlist><context>server config</context><context>virtual host</context>
462 <context>directory</context><context>.htaccess</context>
464 <override>Options</override>
465 <status>Experimental</status>
468 <p>This directive enables the generation of
469 <code>Content-MD5</code> headers as defined in RFC1864
470 respectively RFC2068.</p>
472 <p>MD5 is an algorithm for computing a "message digest"
473 (sometimes called "fingerprint") of arbitrary-length data, with
474 a high degree of confidence that any alterations in the data
475 will be reflected in alterations in the message digest.</p>
477 <p>The <code>Content-MD5</code> header provides an end-to-end
478 message integrity check (MIC) of the entity-body. A proxy or
479 client may check this header for detecting accidental
480 modification of the entity-body in transit. Example header:</p>
483 Content-MD5: AuLb7Dp1rqtRtxz2m9kRpA==
486 <p>Note that this can cause performance problems on your server
487 since the message digest is computed on every request (the
488 values are not cached).</p>
490 <p><code>Content-MD5</code> is only sent for documents served
491 by the <module>core</module>, and not by any module. For example,
492 SSI documents, output from CGI scripts, and byte range responses
493 do not have this header.</p>
498 <name>DefaultType</name>
499 <description>MIME content-type that will be sent if the
500 server cannot determine a type in any other way</description>
501 <syntax>DefaultType <var>MIME-type</var></syntax>
502 <default>DefaultType text/plain</default>
503 <contextlist><context>server config</context><context>virtual host</context>
504 <context>directory</context><context>.htaccess</context>
506 <override>FileInfo</override>
509 <p>There will be times when the server is asked to provide a
510 document whose type cannot be determined by its MIME types
513 <p>The server must inform the client of the content-type of the
514 document, so in the event of an unknown type it uses the
515 <code>DefaultType</code>. For example:</p>
518 DefaultType image/gif
521 <p>would be appropriate for a directory which contained many GIF
522 images with filenames missing the <code>.gif</code> extension.</p>
524 <p>Note that unlike <directive
525 module="core">ForceType</directive>, this directive only
526 provides the default mime-type. All other mime-type definitions,
527 including filename extensions, that might identify the media type
528 will override this default.</p>
532 <directivesynopsis type="section">
533 <name>Directory</name>
534 <description>Enclose a group of directives that apply only to the
535 named file-system directory and sub-directories</description>
536 <syntax><Directory <var>directory-path</var>>
537 ... </Directory></syntax>
538 <contextlist><context>server config</context><context>virtual host</context>
542 <p><directive type="section">Directory</directive> and
543 <code></Directory></code> are used to enclose a group of
544 directives that will apply only to the named directory and
545 sub-directories of that directory. Any directive that is allowed
546 in a directory context may be used. <var>Directory-path</var> is
547 either the full path to a directory, or a wild-card string using
548 Unix shell-style matching. In a wild-card string, <code>?</code> matches
549 any single character, and <code>*</code> matches any sequences of
550 characters. You may also use <code>[]</code> character ranges. None
551 of the wildcards match a `/' character, so <code><Directory
552 /*/public_html></code> will not match
553 <code>/home/user/public_html</code>, but <code><Directory
554 /home/*/public_html></code> will match. Example:</p>
557 <Directory /usr/local/httpd/htdocs><br />
559 Options Indexes FollowSymLinks<br />
565 <p>Be careful with the <var>directory-path</var> arguments:
566 They have to literally match the filesystem path which Apache uses
567 to access the files. Directives applied to a particular
568 <code><Directory></code> will not apply to files accessed from
569 that same directory via a different path, such as via different symbolic
574 expressions can also be used, with the addition of the
575 <code>~</code> character. For example:</p>
578 <Directory ~ "^/www/.*/[0-9]{3}">
581 <p>would match directories in <code>/www/</code> that consisted of
584 <p>If multiple (non-regular expression) <directive
585 type="section">Directory</directive> sections
586 match the directory (or one of its parents) containing a document,
587 then the directives are applied in the order of shortest match
588 first, interspersed with the directives from the <a
589 href="#accessfilename">.htaccess</a> files. For example,
593 <Directory /><br />
595 AllowOverride None<br />
597 </Directory><br />
599 <Directory /home/><br />
601 AllowOverride FileInfo<br />
606 <p>for access to the document <code>/home/web/dir/doc.html</code>
610 <li>Apply directive <code>AllowOverride None</code>
611 (disabling <code>.htaccess</code> files).</li>
613 <li>Apply directive <code>AllowOverride FileInfo</code> (for
614 directory <code>/home</code>).</li>
616 <li>Apply any <code>FileInfo</code> directives in
617 <code>/home/.htaccess</code>, <code>/home/web/.htaccess</code> and
618 <code>/home/web/dir/.htaccess</code> in that order.</li>
621 <p>Regular expressions are not considered until after all of the
622 normal sections have been applied. Then all of the regular
623 expressions are tested in the order they appeared in the
624 configuration file. For example, with</p>
627 <Directory ~ abc$><br />
629 # ... directives here ...<br />
634 <p>the regular expression section won't be considered until after
635 all normal <directive type="section">Directory</directive>s and
636 <code>.htaccess</code> files have been applied. Then the regular
637 expression will match on <code>/home/abc/public_html/abc</code> and
638 the corresponding <directive type="section">Directory</directive> will
641 <p><strong>Note that the default Apache access for
642 <code><Directory /></code> is <code>Allow from All</code>.
643 This means that Apache will serve any file mapped from an URL. It is
644 recommended that you change this with a block such
648 <Directory /><br />
650 Order Deny,Allow<br />
656 <p><strong>and then override this for directories you
657 <em>want</em> accessible. See the <a
658 href="../misc/security_tips.html">Security Tips</a> page for more
659 details.</strong></p>
661 <p>The directory sections occur in the <code>httpd.conf</code> file.
662 <directive type="section">Directory</directive> directives
663 cannot nest, and cannot appear in a <directive module="core"
664 type="section">Limit</directive> or <directive module="core"
665 type="section">LimitExcept</directive> section.</p>
667 <seealso><a href="../sections.html">How <Directory>,
668 <Location> and <Files> sections work</a> for an
669 explanation of how these different sections are combined when a
670 request is received</seealso>
673 <directivesynopsis type="section">
674 <name>DirectoryMatch</name>
675 <description>Enclose directives that apply to
676 file-system directories matching a regular expression and their
677 subdirectories</description>
678 <syntax><DirectoryMatch <var>regex</var>>
679 ... </DirectoryMatch></syntax>
680 <contextlist><context>server config</context><context>virtual host</context>
684 <p><directive type="section">DirectoryMatch</directive> and
685 <code></DirectoryMatch></code> are used to enclose a group
686 of directives which will apply only to the named directory and
687 sub-directories of that directory, the same as <directive
688 module="core" type="section">Directory</directive>. However, it
689 takes as an argument a regular expression. For example:</p>
692 <DirectoryMatch "^/www/.*/[0-9]{3}">
695 <p>would match directories in <code>/www/</code> that consisted of three
698 <seealso><directive type="section" module="core">Directory</directive> for
699 a description of how regular expressions are mixed in with normal
700 <directive type="section">Directory</directive>s</seealso>
702 href="../sections.html">How <Directory>, <Location> and
703 <Files> sections work</a> for an explanation of how these different
704 sections are combined when a request is received</seealso>
708 <name>DocumentRoot</name>
709 <description>Directory that forms the main document tree visible
710 from the web</description>
711 <syntax>DocumentRoot <var>directory-path</var></syntax>
712 <default>DocumentRoot /usr/local/apache/htdocs</default>
713 <contextlist><context>server config</context><context>virtual host</context>
717 <p>This directive sets the directory from which <code>httpd</code>
718 will serve files. Unless matched by a directive like <directive
719 module="mod_alias">Alias</directive>, the server appends the
720 path from the requested URL to the document root to make the
721 path to the document. Example:</p>
724 DocumentRoot /usr/web
728 <code>http://www.my.host.com/index.html</code> refers to
729 <code>/usr/web/index.html</code>. If the <var>directory-path</var> is
730 not absolute then it is assumed to be relative to the <directive
731 module="core">ServerRoot</directive>.</p>
733 <p>The <directive>DocumentRoot</directive> should be specified without
734 a trailing slash.</p>
736 <seealso><a href="../urlmapping.html">Mapping URLs to Filesystem
737 Location</a></seealso>
741 <name>EnableMMAP</name>
742 <description>Use memory-mapping to read files during delivery</description>
743 <syntax>EnableMMAP On|Off</syntax>
744 <default>EnableMMAP On</default>
745 <contextlist><context>server config</context><context>virtual host</context>
746 <context>directory</context><context>.htaccess</context>
748 <override>FileInfo</override>
751 <p>This directive controls whether the <code>httpd</code> may use
752 memory-mapping if it needs to read the contents of a file during
753 delivery. By default, when the handling of a request requires
754 access to the data within a file -- for example, when delivering a
755 server-parsed file using <module>mod_include</module> -- Apache
756 memory-maps the file if the OS supports it.</p>
758 <p>This memory-mapping sometimes yields a performance improvement.
759 But in some environments, it is better to disable the memory-mapping
760 to prevent operational problems:</p>
763 <li>On some multiprocessor systems, memory-mapping can reduce the
764 performance of the <code>httpd</code>.</li>
765 <li>With an NFS-mounted <directive module="core">DocumentRoot</directive>,
766 the <code>httpd</code> may crash due to a segmentation fault if a file
767 is deleted or truncated while the <code>httpd</code> has it
771 <p>For server configurations that are vulnerable to these problems,
772 you should disable memory-mapping of delivered files by specifying:</p>
778 <p>For NFS mounted files, this feature may be disabled explicitly for
779 the offending files by specifying:</p>
782 <Directory "/path-to-nfs-files">
792 <name>EnableSendfile</name>
793 <description>Use the kernel sendfile support to deliver files to the client</description>
794 <syntax>EnableSendfile On|Off</syntax>
795 <default>EnableSendfile On</default>
796 <contextlist><context>server config</context><context>virtual host</context>
797 <context>directory</context><context>.htaccess</context>
799 <override>FileInfo</override>
800 <compatibility>Available in version 2.0.44 and later</compatibility>
803 <p>This directive controls whether <code>httpd</code> may use the sendfile
804 support from the kernel to transmit file contents to the client.
805 By default, when the handling of a request requires no access
806 to the data within a file -- for example, when delivering a
807 static file -- Apache uses sendfile to deliver the file contents
808 without ever reading the file if the OS supports it.</p>
810 <p>This sendfile mechanism avoids seperate read and send operations,
811 and buffer allocations. But on some platforms or within some
812 filesystems, it is better to disable this feature to avoid
813 operational problems:</p>
816 <li>Some platforms may have broken sendfile support that the build
817 system did not detect, especially if the binaries were built on
818 another box and moved to such a machine with broken sendfile
820 <li>On Linux the use of sendfile triggers TCP-checksum
821 offloading bugs on certain networking cards when using IPv6.</li>
822 <li>With a network-mounted <directive
823 module="core">DocumentRoot</directive> (e.g., NFS or SMB),
824 the kernel may be unable to serve the network file through
828 <p>For server configurations that are vulnerable to these problems,
829 you should disable this feature by specifying:</p>
835 <p>For NFS or SMB mounted files, this feature may be disabled explicitly
836 for the offending files by specifying:</p>
839 <Directory "/path-to-nfs-files">
849 <name>ErrorDocument</name>
850 <description>What the server will return to the client
851 in case of an error</description>
852 <syntax>ErrorDocument <var>error-code</var> <var>document</var></syntax>
853 <contextlist><context>server config</context><context>virtual host</context>
854 <context>directory</context><context>.htaccess</context>
856 <override>FileInfo</override>
857 <compatibility>Quoting syntax for text messages is different in Apache
861 <p>In the event of a problem or error, Apache can be configured
862 to do one of four things,</p>
865 <li>output a simple hardcoded error message</li>
867 <li>output a customized message</li>
869 <li>redirect to a local <var>URL-path</var> to handle the
872 <li>redirect to an external <var>URL</var> to handle the
876 <p>The first option is the default, while options 2-4 are
877 configured using the <directive>ErrorDocument</directive>
878 directive, which is followed by the HTTP response code and a URL
879 or a message. Apache will sometimes offer additional information
880 regarding the problem/error.</p>
882 <p>URLs can begin with a slash (/) for local URLs, or be a full
883 URL which the client can resolve. Alternatively, a message can
884 be provided to be displayed by the browser. Examples:</p>
887 ErrorDocument 500 http://foo.example.com/cgi-bin/tester<br />
888 ErrorDocument 404 /cgi-bin/bad_urls.pl<br />
889 ErrorDocument 401 /subscription_info.html<br />
890 ErrorDocument 403 "Sorry can't allow you access today"
893 <p>Note that when you specify an <directive>ErrorDocument</directive>
894 that points to a remote URL (ie. anything with a method such as
895 <code>http</code> in front of it), Apache will send a redirect to the
896 client to tell it where to find the document, even if the
897 document ends up being on the same server. This has several
898 implications, the most important being that the client will not
899 receive the original error status code, but instead will
900 receive a redirect status code. This in turn can confuse web
901 robots and other clients which try to determine if a URL is
902 valid using the status code. In addition, if you use a remote
903 URL in an <code>ErrorDocument 401</code>, the client will not
904 know to prompt the user for a password since it will not
905 receive the 401 status code. Therefore, <strong>if you use an
906 <code>ErrorDocument 401</code> directive then it must refer to a local
907 document.</strong></p>
909 <p>Microsoft Internet Explorer (MSIE) will by default ignore
910 server-generated error messages when they are "too small" and substitute
911 its own "friendly" error messages. The size threshold varies depending on
912 the type of error, but in general, if you make your error document
913 greater than 512 bytes, then MSIE will show the server-generated
914 error rather than masking it. More information is available in
915 Microsoft Knowledgebase article <a
916 href="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q294807"
919 <p>Prior to version 2.0, messages were indicated by prefixing
920 them with a single unmatched double quote character.</p>
923 <seealso><a href="../custom-error.html">documentation of
924 customizable responses</a></seealso>
928 <name>ErrorLog</name>
929 <description>Location where the server will log errors</description>
930 <syntax> ErrorLog <var>file-path</var>|syslog[:<var>facility</var>]</syntax>
931 <default>ErrorLog logs/error_log (Unix) ErrorLog logs/error.log (Windows and OS/2)</default>
932 <contextlist><context>server config</context><context>virtual host</context>
936 <p>The <directive>ErrorLog</directive> directive sets the name of
937 the file to which the server will log any errors it encounters. If
938 the <var>file-path</var> is not absolute then it is assumed to be
939 relative to the <directive module="core">ServerRoot</directive>.</p>
941 <example><title>Example</title>
942 ErrorLog /var/log/httpd/error_log
945 <p>If the <var>file-path</var>
946 begins with a pipe (|) then it is assumed to be a command to spawn
947 to handle the error log.</p>
949 <example><title>Example</title>
950 ErrorLog "|/usr/local/bin/httpd_errors"
953 <p>Using <code>syslog</code> instead of a filename enables logging
954 via syslogd(8) if the system supports it. The default is to use
955 syslog facility <code>local7</code>, but you can override this by
956 using the <code>syslog:<var>facility</var></code> syntax where
957 <var>facility</var> can be one of the names usually documented in
960 <example><title>Example</title>
964 <p>SECURITY: See the <a
965 href="../misc/security_tips.html#serverroot">security tips</a>
966 document for details on why your security could be compromised
967 if the directory where logfiles are stored is writable by
968 anyone other than the user that starts the server.</p>
969 <note type="warning"><title>Note</title>
970 <p>When entering a file path on non-Unix platforms, care should be taken
971 to make sure that only forward slashed are used even though the platform
972 may allow the use of back slashes. In general it is a good idea to always
973 use forward slashes throughout the configuration files.</p>
976 <seealso><directive module="core">LogLevel</directive></seealso>
977 <seealso><a href="../logs.html">Apache Log Files</a></seealso>
981 <name>FileETag</name>
982 <description>File attributes used to create the ETag
983 HTTP response header</description>
984 <syntax>FileETag <var>component</var> ...</syntax>
985 <default>FileETag INode MTime Size</default>
986 <contextlist><context>server config</context><context>virtual host</context>
987 <context>directory</context><context>.htaccess</context>
989 <override>FileInfo</override>
993 The <directive>FileETag</directive> directive configures the file
994 attributes that are used to create the <code>ETag</code> (entity
995 tag) response header field when the document is based on a file.
996 (The <code>ETag</code> value is used in cache management to save
997 network bandwidth.) In Apache 1.3.22 and earlier, the
998 <code>ETag</code> value was <em>always</em> formed
999 from the file's inode, size, and last-modified time (mtime). The
1000 <directive>FileETag</directive> directive allows you to choose
1001 which of these -- if any -- should be used. The recognized keywords are:
1005 <dt><strong>INode</strong></dt>
1006 <dd>The file's i-node number will be included in the calculation</dd>
1007 <dt><strong>MTime</strong></dt>
1008 <dd>The date and time the file was last modified will be included</dd>
1009 <dt><strong>Size</strong></dt>
1010 <dd>The number of bytes in the file will be included</dd>
1011 <dt><strong>All</strong></dt>
1012 <dd>All available fields will be used. This is equivalent to:
1013 <example>FileETag INode MTime Size</example></dd>
1014 <dt><strong>None</strong></dt>
1015 <dd>If a document is file-based, no <code>ETag</code> field will be
1016 included in the response</dd>
1019 <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
1020 keywords may be prefixed with either <code>+</code> or <code>-</code>,
1021 which allow changes to be made to the default setting inherited
1022 from a broader scope. Any keyword appearing without such a prefix
1023 immediately and completely cancels the inherited setting.</p>
1025 <p>If a directory's configuration includes
1026 <code>FileETag INode MTime Size</code>, and a
1027 subdirectory's includes <code>FileETag -INode</code>,
1028 the setting for that subdirectory (which will be inherited by
1029 any sub-subdirectories that don't override it) will be equivalent to
1030 <code>FileETag MTime Size</code>.</p>
1032 </directivesynopsis>
1034 <directivesynopsis type="section">
1036 <description>Contains directives that apply to matched
1037 filenames</description>
1038 <syntax><Files <var>filename</var>> ... </Files></syntax>
1039 <contextlist><context>server config</context><context>virtual host</context>
1040 <context>directory</context><context>.htaccess</context>
1042 <override>All</override>
1045 <p>The <directive type="section">Files</directive> directive
1046 limits the scope of the enclosed directives by filename. It is comparable
1047 to the <directive module="core" type="section">Directory</directive>
1048 and <directive module="core" type="section">Location</directive>
1049 directives. It should be matched with a <code></Files></code>
1050 directive. The directives given within this section will be applied to
1051 any object with a basename (last component of filename) matching the
1052 specified filename. <directive type="section">Files</directive>
1053 sections are processed in the order they appear in the
1054 configuration file, after the <directive module="core"
1055 type="section">Directory</directive> sections and
1056 <code>.htaccess</code> files are read, but before <directive
1057 type="section" module="core">Location</directive> sections. Note
1058 that <directive type="section">Files</directive> can be nested
1059 inside <directive type="section"
1060 module="core">Directory</directive> sections to restrict the
1061 portion of the filesystem they apply to.</p>
1063 <p>The <var>filename</var> argument should include a filename, or
1064 a wild-card string, where <code>?</code> matches any single character,
1065 and <code>*</code> matches any sequences of characters. Extended regular
1066 expressions can also be used, with the addition of the
1067 <code>~</code> character. For example:</p>
1070 <Files ~ "\.(gif|jpe?g|png)$">
1073 <p>would match most common Internet graphics formats. <directive
1074 module="core" type="section">FilesMatch</directive> is preferred,
1077 <p>Note that unlike <directive type="section"
1078 module="core">Directory</directive> and <directive type="section"
1079 module="core">Location</directive> sections, <directive
1080 type="section">Files</directive> sections can be used inside
1081 <code>.htaccess</code> files. This allows users to control access to
1082 their own files, at a file-by-file level.</p>
1085 <seealso><a href="../sections.html">How <Directory>, <Location>
1086 and <Files> sections work</a> for an explanation of how these
1087 different sections are combined when a request is received</seealso>
1088 </directivesynopsis>
1090 <directivesynopsis type="section">
1091 <name>FilesMatch</name>
1092 <description>Contains directives that apply to regular-expression matched
1093 filenames</description>
1094 <syntax><FilesMatch <var>regex</var>> ... </FilesMatch></syntax>
1095 <contextlist><context>server config</context><context>virtual host</context>
1096 <context>directory</context><context>.htaccess</context>
1098 <override>All</override>
1101 <p>The <directive type="section">FilesMatch</directive> directive
1102 limits the scope of the enclosed directives by filename, just as the
1103 <directive module="core" type="section">Files</directive> directive
1104 does. However, it accepts a regular expression. For example:</p>
1107 <FilesMatch "\.(gif|jpe?g|png)$">
1110 <p>would match most common Internet graphics formats.</p>
1113 <seealso><a href="../sections.html">How <Directory>, <Location>
1114 and <Files> sections work</a> for an explanation of how these
1115 different sections are combined when a request is received</seealso>
1116 </directivesynopsis>
1119 <name>ForceType</name>
1120 <description>Forces all matching files to be served with the specified
1121 MIME content-type</description>
1122 <syntax>ForceType <var>MIME-type</var>|None</syntax>
1123 <contextlist><context>directory</context><context>.htaccess</context>
1125 <override>FileInfo</override>
1126 <compatibility>Moved to the core in Apache 2.0</compatibility>
1129 <p>When placed into an <code>.htaccess</code> file or a
1130 <directive type="section" module="core">Directory</directive>, or
1131 <directive type="section" module="core">Location</directive> or
1132 <directive type="section" module="core">Files</directive>
1133 section, this directive forces all matching files to be served
1134 with the content type identification given by
1135 <var>MIME-type</var>. For example, if you had a directory full of
1136 GIF files, but did not want to label them all with <code>.gif</code>,
1137 you might want to use:</p>
1143 <p>Note that unlike <directive module="core">DefaultType</directive>,
1144 this directive overrides all mime-type associations, including
1145 filename extensions, that might identify the media type.</p>
1147 <p>You can override any <directive>ForceType</directive> setting
1148 by using the value of <code>None</code>:</p>
1151 # force all files to be image/gif:<br />
1152 <Location /images><br />
1154 ForceType image/gif<br />
1156 </Location><br />
1158 # but normal mime-type associations here:<br />
1159 <Location /images/mixed><br />
1161 ForceType None<br />
1166 </directivesynopsis>
1169 <name>HostnameLookups</name>
1170 <description>Enables DNS lookups on client IP addresses</description>
1171 <syntax>HostnameLookups On|Off|Double</syntax>
1172 <default>HostnameLookups Off</default>
1173 <contextlist><context>server config</context><context>virtual host</context>
1174 <context>directory</context></contextlist>
1177 <p>This directive enables DNS lookups so that host names can be
1178 logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
1179 The value <code>Double</code> refers to doing double-reverse
1180 DNS lookup. That is, after a reverse lookup is performed, a forward
1181 lookup is then performed on that result. At least one of the ip
1182 addresses in the forward lookup must match the original
1183 address. (In "tcpwrappers" terminology this is called
1184 <code>PARANOID</code>.)</p>
1186 <p>Regardless of the setting, when <module>mod_authz_host</module> is
1187 used for controlling access by hostname, a double reverse lookup
1188 will be performed. This is necessary for security. Note that the
1189 result of this double-reverse isn't generally available unless you
1190 set <code>HostnameLookups Double</code>. For example, if only
1191 <code>HostnameLookups On</code> and a request is made to an object
1192 that is protected by hostname restrictions, regardless of whether
1193 the double-reverse fails or not, CGIs will still be passed the
1194 single-reverse result in <code>REMOTE_HOST</code>.</p>
1196 <p>The default is <code>Off</code> in order to save the network
1197 traffic for those sites that don't truly need the reverse
1198 lookups done. It is also better for the end users because they
1199 don't have to suffer the extra latency that a lookup entails.
1200 Heavily loaded sites should leave this directive
1201 <code>Off</code>, since DNS lookups can take considerable
1202 amounts of time. The utility <a
1203 href="../programs/logresolve.html">logresolve</a>, compiled by default
1204 to the <code>bin</code> subdirectory of your installation directory, can
1205 be used to look up host names from logged IP addresses offline.</p>
1207 </directivesynopsis>
1209 <directivesynopsis type="section">
1210 <name>IfDefine</name>
1211 <description>Encloses directives that will be processed only
1212 if a test is true at startup</description>
1213 <syntax><IfDefine [!]<var>parameter-name</var>> ...
1214 </IfDefine></syntax>
1215 <contextlist><context>server config</context><context>virtual host</context>
1216 <context>directory</context><context>.htaccess</context>
1218 <override>All</override>
1221 <p>The <code><IfDefine <var>test</var>>...</IfDefine>
1222 </code> section is used to mark directives that are conditional. The
1223 directives within an <directive type="section">IfDefine</directive>
1224 section are only processed if the <var>test</var> is true. If <var>
1225 test</var> is false, everything between the start and end markers is
1228 <p>The <var>test</var> in the <directive type="section"
1229 >IfDefine</directive> section directive can be one of two forms:</p>
1232 <li><var>parameter-name</var></li>
1234 <li><code>!</code><var>parameter-name</var></li>
1237 <p>In the former case, the directives between the start and end
1238 markers are only processed if the parameter named
1239 <var>parameter-name</var> is defined. The second format reverses
1240 the test, and only processes the directives if
1241 <var>parameter-name</var> is <strong>not</strong> defined.</p>
1243 <p>The <var>parameter-name</var> argument is a define as given on
1244 the <code>httpd</code> command line via <code>-D<var>parameter-</var>
1245 </code>, at the time the server was started.</p>
1247 <p><directive type="section">IfDefine</directive> sections are
1248 nest-able, which can be used to implement simple
1249 multiple-parameter tests. Example:</p>
1252 httpd -DReverseProxy ...<br />
1255 <IfDefine ReverseProxy><br />
1257 LoadModule rewrite_module modules/mod_rewrite.so<br />
1258 LoadModule proxy_module modules/libproxy.so<br />
1263 </directivesynopsis>
1265 <directivesynopsis type="section">
1266 <name>IfModule</name>
1267 <description>Encloses directives that are processed conditional on the
1268 presence or absence of a specific module</description>
1269 <syntax><IfModule [!]<var>module-name</var>> ...
1270 </IfModule></syntax>
1271 <contextlist><context>server config</context><context>virtual host</context>
1272 <context>directory</context><context>.htaccess</context>
1274 <override>All</override>
1277 <p>The <code><IfModule <var>test</var>>...</IfModule></code>
1278 section is used to mark directives that are conditional on the presence of
1279 a specific module. The directives within an <directive type="section"
1280 >IfModule</directive> section are only processed if the <var>test</var>
1281 is true. If <var>test</var> is false, everything between the start and
1282 end markers is ignored.</p>
1284 <p>The <var>test</var> in the <directive type="section"
1285 >IfModule</directive> section directive can be one of two forms:</p>
1288 <li><var>module name</var></li>
1290 <li>!<var>module name</var></li>
1293 <p>In the former case, the directives between the start and end
1294 markers are only processed if the module named <var>module
1295 name</var> is included in Apache -- either compiled in or
1296 dynamically loaded using <directive module="mod_so"
1297 >LoadModule</directive>. The second format reverses the test,
1298 and only processes the directives if <var>module name</var> is
1299 <strong>not</strong> included.</p>
1301 <p>The <var>module name</var> argument is the file name of the
1302 module, at the time it was compiled. For example,
1303 <code>mod_rewrite.c</code>. If a module consists of several
1304 source files, use the name of the file containing the string
1305 <code>STANDARD20_MODULE_STUFF</code>.</p>
1307 <p><directive type="section">IfModule</directive> sections are
1308 nest-able, which can be used to implement simple multiple-module
1311 <note>This section should only be used if you need to have one
1312 configuration file that works whether or not a specific module
1313 is available. In normal operation, directives need not be
1314 placed in <directive type="section">IfModule</directive>
1317 </directivesynopsis>
1320 <name>Include</name>
1321 <description>Includes other configuration files from within
1322 the server configuration files</description>
1323 <syntax>Include <var>file-path</var>|<var>directory-path</var></syntax>
1324 <contextlist><context>server config</context><context>virtual host</context>
1325 <context>directory</context>
1327 <compatibility>Wildcard matching available in 2.0.41 and later</compatibility>
1330 <p>This directive allows inclusion of other configuration files
1331 from within the server configuration files.</p>
1333 <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used to
1334 include several files at once, in alphabetical order. In
1335 addition, if <directive>Include</directive> points to a directory,
1336 rather than a file, Apache will read all files in that directory
1337 and any subdirectory. But including entire directories is not
1338 recommended, because it is easy to accidentally leave temporary
1339 files in a directory that can cause <code>httpd</code> to
1342 <p>The file path specified may be an absolute path, or may be relative
1343 to the <directive module="core">ServerRoot</directive> directory.</p>
1348 Include /usr/local/apache2/conf/ssl.conf<br />
1349 Include /usr/local/apache2/conf/vhosts/*.conf
1352 <p>Or, providing paths relative to your <directive
1353 module="core">ServerRoot</directive> directory:</p>
1356 Include conf/ssl.conf<br />
1357 Include conf/vhosts/*.conf
1360 <p>Running <code>apachectl configtest</code> will give you a list
1361 of the files that are being processed during the configuration
1365 root@host# apachectl configtest<br />
1366 Processing config file: /usr/local/apache2/conf/ssl.conf<br />
1367 Processing config file: /usr/local/apache2/conf/vhosts/vhost1.conf<br />
1368 Processing config file: /usr/local/apache2/conf/vhosts/vhost2.conf<br />
1373 <seealso><a href="../programs/apachectl.html">apachectl</a></seealso>
1374 </directivesynopsis>
1377 <name>KeepAlive</name>
1378 <description>Enables HTTP persistent connections</description>
1379 <syntax>KeepAlive On|Off</syntax>
1380 <default>KeepAlive On</default>
1381 <contextlist><context>server config</context><context>virtual host</context>
1385 <p>The Keep-Alive extension to HTTP/1.0 and the persistent
1386 connection feature of HTTP/1.1 provide long-lived HTTP sessions
1387 which allow multiple requests to be sent over the same TCP
1388 connection. In some cases this has been shown to result in an
1389 almost 50% speedup in latency times for HTML documents with
1390 many images. To enable Keep-Alive connections, set
1391 <code>KeepAlive On</code>.</p>
1393 <p>For HTTP/1.0 clients, Keep-Alive connections will only be
1394 used if they are specifically requested by a client. In
1395 addition, a Keep-Alive connection with an HTTP/1.0 client can
1396 only be used when the length of the content is known in
1397 advance. This implies that dynamic content such as CGI output,
1398 SSI pages, and server-generated directory listings will
1399 generally not use Keep-Alive connections to HTTP/1.0 clients.
1400 For HTTP/1.1 clients, persistent connections are the default
1401 unless otherwise specified. If the client requests it, chunked
1402 encoding will be used in order to send content of unknown
1403 length over persistent connections.</p>
1406 <seealso><directive module="core">MaxKeepAliveRequests</directive></seealso>
1407 </directivesynopsis>
1410 <name>KeepAliveTimeout</name>
1411 <description>Amount of time the server will wait for subsequent
1412 requests on a persistent connection</description>
1413 <syntax>KeepAliveTimeout <var>seconds</var></syntax>
1414 <default>KeepAliveTimeout 15</default>
1415 <contextlist><context>server config</context><context>virtual host</context>
1419 <p>The number of seconds Apache will wait for a subsequent
1420 request before closing the connection. Once a request has been
1421 received, the timeout value specified by the
1422 <directive module="core">Timeout</directive> directive applies.</p>
1424 <p>Setting <directive>KeepAliveTimeout</directive> to a high value
1425 may cause performance problems in heavily loaded servers. The
1426 higher the timeout, the more server processes will be kept
1427 occupied waiting on connections with idle clients.</p>
1429 </directivesynopsis>
1431 <directivesynopsis type="section">
1433 <description>Restrict enclosed access controls to only certain HTTP
1434 methods</description>
1435 <syntax><Limit <var>method</var> [<var>method</var>] ... > ...
1436 </Limit></syntax>
1437 <contextlist><context>server config</context><context>virtual host</context>
1438 <context>directory</context><context>.htaccess</context>
1440 <override>All</override>
1443 <p>Access controls are normally effective for
1444 <strong>all</strong> access methods, and this is the usual
1445 desired behavior. <strong>In the general case, access control
1446 directives should not be placed within a
1447 <directive type="section">Limit</directive> section.</strong></p>
1449 <p>The purpose of the <directive type="section">Limit</directive>
1450 directive is to restrict the effect of the access controls to the
1451 nominated HTTP methods. For all other methods, the access
1452 restrictions that are enclosed in the <directive
1453 type="section">Limit</directive> bracket <strong>will have no
1454 effect</strong>. The following example applies the access control
1455 only to the methods <code>POST</code>, <code>PUT</code>, and
1456 <code>DELETE</code>, leaving all other methods unprotected:</p>
1459 <Limit POST PUT DELETE><br />
1461 Require valid-user<br />
1466 <p>The method names listed can be one or more of: <code>GET</code>,
1467 <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
1468 <code>CONNECT</code>, <code>OPTIONS</code>,
1469 <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
1470 <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
1471 <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
1472 case-sensitive.</strong> If <code>GET</code> is used it will also
1473 restrict <code>HEAD</code> requests. The <code>TRACE</code> method
1474 cannot be limited.</p>
1476 <note type="warning">A <directive type="section"
1477 module="core">LimitExcept</directive> section should always be
1478 used in preference to a <directive type="section"
1479 module="core">Limit</directive> section when restricting access,
1480 since a <directive type="section"
1481 module="core">LimitExcept</directive> section provides protection
1482 against arbitrary methods.</note>
1485 </directivesynopsis>
1487 <directivesynopsis type="section">
1488 <name>LimitExcept</name>
1489 <description>Restrict access controls to all HTTP methods
1490 except the named ones</description>
1491 <syntax><LimitExcept <var>method</var> [<var>method</var>] ... > ...
1492 </LimitExcept></syntax>
1493 <contextlist><context>server config</context><context>virtual host</context>
1494 <context>directory</context><context>.htaccess</context>
1496 <override>All</override>
1499 <p><directive type="section">LimitExcept</directive> and
1500 <code></LimitExcept></code> are used to enclose
1501 a group of access control directives which will then apply to any
1502 HTTP access method <strong>not</strong> listed in the arguments;
1503 i.e., it is the opposite of a <directive type="section"
1504 module="core">Limit</directive> section and can be used to control
1505 both standard and nonstandard/unrecognized methods. See the
1506 documentation for <directive module="core"
1507 type="section">Limit</directive> for more details.</p>
1512 <LimitExcept POST GET><br />
1514 Require valid-user<br />
1516 </LimitExcept>
1520 </directivesynopsis>
1523 <name>LimitInternalRecursion</name>
1524 <description>Determine maximum number of internal redirects and nested
1525 subrequests</description>
1526 <syntax>LimitInternalRecursion <var>number</var> [<var>number</var>]</syntax>
1527 <default>LimitInternalRecursion 10</default>
1528 <contextlist><context>server config</context><context>virtual host</context>
1530 <compatibility>Available in Apache 2.0.47 and later</compatibility>
1533 <p>An internal redirect happens, for example, when using the <directive
1534 module="mod_actions">Action</directive> directive, which internally
1535 redirects the original request to a CGI script. A subrequest is Apache's
1536 mechanism to find out what would happen for some URI if it were requested.
1537 For example, <module>mod_dir</module> uses subrequests to look for the
1538 files listed in the <directive module="mod_dir">DirectoryIndex</directive>
1541 <p><directive>LimitInternalRecursion</directive> prevents the server
1542 from crashing when entering an infinite loop of internal redirects or
1543 subrequests. Such loops are usually caused by misconfigurations.</p>
1545 <p>The directive stores two different limits, which are evaluated on
1546 per-request basis. The first <var>number</var> is the maximum number of
1547 internal redirects, that may follow each other. The second <var>number</var>
1548 determines, how deep subrequests may be nested. If you specify only one
1549 <var>number</var>, it will be assigned to both limits.</p>
1551 <example><title>Example</title>
1552 LimitInternalRecursion 5
1555 </directivesynopsis>
1558 <name>LimitRequestBody</name>
1559 <description>Restricts the total size of the HTTP request body sent
1560 from the client</description>
1561 <syntax>LimitRequestBody <var>bytes</var></syntax>
1562 <default>LimitRequestBody 0</default>
1563 <contextlist><context>server config</context><context>virtual host</context>
1564 <context>directory</context><context>.htaccess</context>
1566 <override>All</override>
1569 <p>This directive specifies the number of <var>bytes</var> from 0
1570 (meaning unlimited) to 2147483647 (2GB) that are allowed in a
1573 <p>The <directive>LimitRequestBody</directive> directive allows
1574 the user to set a limit on the allowed size of an HTTP request
1575 message body within the context in which the directive is given
1576 (server, per-directory, per-file or per-location). If the client
1577 request exceeds that limit, the server will return an error
1578 response instead of servicing the request. The size of a normal
1579 request message body will vary greatly depending on the nature of
1580 the resource and the methods allowed on that resource. CGI scripts
1581 typically use the message body for retrieving form information.
1582 Implementations of the <code>PUT</code> method will require
1583 a value at least as large as any representation that the server
1584 wishes to accept for that resource.</p>
1586 <p>This directive gives the server administrator greater
1587 control over abnormal client request behavior, which may be
1588 useful for avoiding some forms of denial-of-service
1591 <p>If, for example, you are permitting file upload to a particular
1592 location, and wish to limit the size of the uploaded file to 100K,
1593 you might use the following directive:</p>
1596 LimitRequestBody 102400
1600 </directivesynopsis>
1603 <name>LimitRequestFields</name>
1604 <description>Limits the number of HTTP request header fields that
1605 will be accepted from the client</description>
1606 <syntax>LimitRequestFields <var>number</var></syntax>
1607 <default>LimitRequestFields 100</default>
1608 <contextlist><context>server config</context></contextlist>
1611 <p><var>Number</var> is an integer from 0 (meaning unlimited) to
1612 32767. The default value is defined by the compile-time
1613 constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
1616 <p>The <directive>LimitRequestFields</directive> directive allows
1617 the server administrator to modify the limit on the number of
1618 request header fields allowed in an HTTP request. A server needs
1619 this value to be larger than the number of fields that a normal
1620 client request might include. The number of request header fields
1621 used by a client rarely exceeds 20, but this may vary among
1622 different client implementations, often depending upon the extent
1623 to which a user has configured their browser to support detailed
1624 content negotiation. Optional HTTP extensions are often expressed
1625 using request header fields.</p>
1627 <p>This directive gives the server administrator greater
1628 control over abnormal client request behavior, which may be
1629 useful for avoiding some forms of denial-of-service attacks.
1630 The value should be increased if normal clients see an error
1631 response from the server that indicates too many fields were
1632 sent in the request.</p>
1637 LimitRequestFields 50
1641 </directivesynopsis>
1644 <name>LimitRequestFieldSize</name>
1645 <description>Limits the size of the HTTP request header allowed from the
1646 client</description>
1647 <syntax>LimitRequestFieldsize <var>bytes</var></syntax>
1648 <default>LimitRequestFieldsize 8190</default>
1649 <contextlist><context>server config</context></contextlist>
1652 <p>This directive specifies the number of <var>bytes</var> from 0
1653 to the value of the compile-time constant
1654 <code>DEFAULT_LIMIT_REQUEST_FIELDSIZE</code> (8190 as
1655 distributed) that will be allowed in an HTTP request
1658 <p>The <directive>LimitRequestFieldSize</directive> directive
1659 allows the server administrator to reduce the limit on the allowed
1660 size of an HTTP request header field below the normal input buffer
1661 size compiled with the server. A server needs this value to be
1662 large enough to hold any one header field from a normal client
1663 request. The size of a normal request header field will vary
1664 greatly among different client implementations, often depending
1665 upon the extent to which a user has configured their browser to
1666 support detailed content negotiation.</p>
1668 <p>This directive gives the server administrator greater
1669 control over abnormal client request behavior, which may be
1670 useful for avoiding some forms of denial-of-service attacks.</p>
1675 LimitRequestFieldSize 4094
1678 <note>Under normal conditions, the value should not be changed from
1682 </directivesynopsis>
1685 <name>LimitRequestLine</name>
1686 <description>Limit the size of the HTTP request line that will be accepted
1687 from the client</description>
1688 <syntax>LimitRequestLine <var>bytes</var></syntax>
1689 <default>LimitRequestLine 8190</default>
1690 <contextlist><context>server config</context></contextlist>
1693 <p>This directive sets the number of <var>bytes</var> from 0 to
1694 the value of the compile-time constant
1695 <code>DEFAULT_LIMIT_REQUEST_LINE</code> (8190 as distributed)
1696 that will be allowed on the HTTP request-line.</p>
1698 <p>The <directive>LimitRequestLine</directive> directive allows
1699 the server administrator to reduce the limit on the allowed size
1700 of a client's HTTP request-line below the normal input buffer size
1701 compiled with the server. Since the request-line consists of the
1702 HTTP method, URI, and protocol version, the
1703 <directive>LimitRequestLine</directive> directive places a
1704 restriction on the length of a request-URI allowed for a request
1705 on the server. A server needs this value to be large enough to
1706 hold any of its resource names, including any information that
1707 might be passed in the query part of a <code>GET</code> request.</p>
1709 <p>This directive gives the server administrator greater
1710 control over abnormal client request behavior, which may be
1711 useful for avoiding some forms of denial-of-service attacks.</p>
1716 LimitRequestLine 4094
1719 <note>Under normal conditions, the value should not be changed from
1722 </directivesynopsis>
1725 <name>LimitXMLRequestBody</name>
1726 <description>Limits the size of an XML-based request body</description>
1727 <syntax>LimitXMLRequestBody <var>bytes</var></syntax>
1728 <default>LimitXMLRequestBody 1000000</default>
1729 <contextlist><context>server config</context><context>virtual host</context>
1730 <context>directory</context><context>.htaccess</context></contextlist>
1731 <override>All</override>
1734 <p>Limit (in bytes) on maximum size of an XML-based request
1735 body. A value of <code>0</code> will disable any checking.</p>
1740 LimitXMLRequestBody 0
1744 </directivesynopsis>
1746 <directivesynopsis type="section">
1747 <name>Location</name>
1748 <description>Applies the enclosed directives only to matching
1750 <syntax><Location
1751 <var>URL-path</var>|<var>URL</var>> ... </Location></syntax>
1752 <contextlist><context>server config</context><context>virtual host</context>
1756 <p>The <directive type="section">Location</directive> directive
1757 limits the scope of the enclosed directives by URL. It is similar to the
1758 <directive type="section" module="core">Directory</directive>
1759 directive, and starts a subsection which is terminated with a
1760 <code></Location></code> directive. <directive
1761 type="section">Location</directive> sections are processed in the
1762 order they appear in the configuration file, after the <directive
1763 type="section" module="core">Directory</directive> sections and
1764 <code>.htaccess</code> files are read, and after the <directive
1765 type="section" module="core">Files</directive> sections.</p>
1767 <p><directive type="section">Location</directive> sections operate
1768 completely outside the filesystem. This has several consequences.
1769 Most importantly, <directive type="section">Location</directive>
1770 directives should not be used to control access to filesystem
1771 locations. Since several different URLs may map to the same
1772 filesystem location, such access controls may by circumvented.</p>
1774 <note><title>When to use <directive
1775 type="section">Location</directive></title>
1777 <p>Use <directive type="section">Location</directive> to apply
1778 directives to content that lives outside the filesystem. For
1779 content that lives in the filesystem, use <directive
1780 type="section" module="core">Directory</directive> and <directive
1781 type="section" module="core">Files</directive>. An exception is
1782 <code><Location /></code>, which is an easy way to
1783 apply a configuration to the entire server.</p>
1786 <p>For all origin (non-proxy) requests, the URL to be matched is a
1787 URL-path of the form <code>/path/</code>. No scheme, hostname,
1788 port, or query string may be included. For proxy requests, the
1789 URL to be matched is of the form
1790 <code>scheme://servername/path</code>, and you must include the
1793 <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
1794 any single character, and <code>*</code> matches any sequences of
1798 expressions can also be used, with the addition of the
1799 <code>~</code> character. For example:</p>
1802 <Location ~ "/(extra|special)/data">
1805 <p>would match URLs that contained the substring <code>/extra/data</code>
1806 or <code>/special/data</code>. The directive <directive
1807 type="section" module="core">LocationMatch</directive> behaves
1808 identical to the regex version of <directive
1809 type="section">Location</directive>.</p>
1811 <p>The <directive type="section">Location</directive>
1812 functionality is especially useful when combined with the
1813 <directive module="core">SetHandler</directive>
1814 directive. For example, to enable status requests, but allow them
1815 only from browsers at <code>foo.com</code>, you might use:</p>
1818 <Location /status><br />
1820 SetHandler server-status<br />
1821 Order Deny,Allow<br />
1823 Allow from .foo.com<br />
1828 <note><title>Note about / (slash)</title>
1829 <p>The slash character has special meaning depending on where in a
1830 URL it appears. People may be used to its behavior in the filesystem
1831 where multiple adjacent slashes are frequently collapsed to a single
1832 slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
1833 <code>/home/foo</code>). In URL-space this is not necessarily true.
1834 The <directive type="section" module="core">LocationMatch</directive>
1835 directive and the regex version of <directive type="section"
1836 >Location</directive> require you to explicitly specify multiple
1837 slashes if that is your intention.</p>
1839 <p>For example, <code><LocationMatch ^/abc></code> would match
1840 the request URL <code>/abc</code> but not the request URL <code>
1841 //abc</code>. The (non-regex) <directive type="section"
1842 >Location</directive> directive behaves similarly when used for
1843 proxy requests. But when (non-regex) <directive type="section"
1844 >Location</directive> is used for non-proxy requests it will
1845 implicitly match multiple slashes with a single slash. For example,
1846 if you specify <code><Location /abc/def></code> and the
1847 request is to <code>/abc//def</code> then it will match.</p>
1850 <seealso><a href="../sections.html">How <Directory>, <Location>
1851 and <Files> sections work</a> for an explanation of how these
1852 different sections are combined when a request is received</seealso>
1853 </directivesynopsis>
1855 <directivesynopsis type="section">
1856 <name>LocationMatch</name>
1857 <description>Applies the enclosed directives only to regular-expression
1858 matching URLs</description>
1859 <syntax><LocationMatch
1860 <var>regex</var>> ... </LocationMatch></syntax>
1861 <contextlist><context>server config</context><context>virtual host</context>
1865 <p>The <directive type="section">LocationMatch</directive> directive
1866 limits the scope of the enclosed directives by URL, in an identical manner
1867 to <directive module="core" type="section">Location</directive>. However,
1868 it takes a regular expression as an argument instead of a simple
1869 string. For example:</p>
1872 <LocationMatch "/(extra|special)/data">
1875 <p>would match URLs that contained the substring <code>/extra/data</code>
1876 or <code>/special/data</code>.</p>
1879 <seealso><a href="../sections.html">How <Directory>, <Location>
1880 and <Files> sections work</a> for an explanation of how these
1881 different sections are combined when a request is received</seealso>
1882 </directivesynopsis>
1885 <name>LogLevel</name>
1886 <description>Controls the verbosity of the ErrorLog</description>
1887 <syntax>LogLevel <var>level</var></syntax>
1888 <default>LogLevel warn</default>
1889 <contextlist><context>server config</context><context>virtual host</context>
1893 <p><directive>LogLevel</directive> adjusts the verbosity of the
1894 messages recorded in the error logs (see <directive
1895 module="core">ErrorLog</directive> directive). The following
1896 <var>level</var>s are available, in order of decreasing
1901 <th><strong>Level</strong> </th>
1903 <th><strong>Description</strong> </th>
1905 <th><strong>Example</strong> </th>
1909 <td><code>emerg</code> </td>
1911 <td>Emergencies - system is unusable.</td>
1913 <td>"Child cannot open lock file. Exiting"</td>
1917 <td><code>alert</code> </td>
1919 <td>Action must be taken immediately.</td>
1921 <td>"getpwuid: couldn't determine user name from uid"</td>
1925 <td><code>crit</code> </td>
1927 <td>Critical Conditions.</td>
1929 <td>"socket: Failed to get a socket, exiting child"</td>
1933 <td><code>error</code> </td>
1935 <td>Error conditions.</td>
1937 <td>"Premature end of script headers"</td>
1941 <td><code>warn</code> </td>
1943 <td>Warning conditions.</td>
1945 <td>"child process 1234 did not exit, sending another
1950 <td><code>notice</code> </td>
1952 <td>Normal but significant condition.</td>
1954 <td>"httpd: caught SIGBUS, attempting to dump core in
1959 <td><code>info</code> </td>
1961 <td>Informational.</td>
1963 <td>"Server seems busy, (you may need to increase
1964 StartServers, or Min/MaxSpareServers)..."</td>
1968 <td><code>debug</code> </td>
1970 <td>Debug-level messages</td>
1972 <td>"Opening config file ..."</td>
1976 <p>When a particular level is specified, messages from all
1977 other levels of higher significance will be reported as well.
1978 <em>E.g.</em>, when <code>LogLevel info</code> is specified,
1979 then messages with log levels of <code>notice</code> and
1980 <code>warn</code> will also be posted.</p>
1982 <p>Using a level of at least <code>crit</code> is
1991 <note><title>Note</title>
1992 <p>When logging to a regular file messages of the level
1993 <code>notice</code> cannot be suppressed and thus are always
1994 logged. However, this doesn't apply when logging is done
1995 using <code>syslog</code>.</p>
1998 </directivesynopsis>
2001 <name>MaxKeepAliveRequests</name>
2002 <description>Number of requests allowed on a persistent
2003 connection</description>
2004 <syntax>MaxKeepAliveRequests <var>number</var></syntax>
2005 <default>MaxKeepAliveRequests 100</default>
2006 <contextlist><context>server config</context><context>virtual host</context>
2010 <p>The <directive>MaxKeepAliveRequests</directive> directive
2011 limits the number of requests allowed per connection when
2012 <directive module="core" >KeepAlive</directive> is on. If it is
2013 set to <code>0</code>, unlimited requests will be allowed. We
2014 recommend that this setting be kept to a high value for maximum
2015 server performance.</p>
2020 MaxKeepAliveRequests 500
2023 </directivesynopsis>
2026 <name>NameVirtualHost</name>
2027 <description>Designates an IP address for name-virtual
2028 hosting</description>
2029 <syntax>NameVirtualHost <var>addr</var>[:<var>port</var>]</syntax>
2030 <contextlist><context>server config</context></contextlist>
2033 <p>The <directive>NameVirtualHost</directive> directive is a
2034 required directive if you want to configure <a
2035 href="../vhosts/">name-based virtual hosts</a>.</p>
2037 <p>Although <var>addr</var> can be hostname it is recommended
2038 that you always use an IP address, e.g.</p>
2041 NameVirtualHost 111.22.33.44
2044 <p>With the <directive>NameVirtualHost</directive> directive you
2045 specify the IP address on which the server will receive requests
2046 for the name-based virtual hosts. This will usually be the address
2047 to which your name-based virtual host names resolve. In cases
2048 where a firewall or other proxy receives the requests and forwards
2049 them on a different IP address to the server, you must specify the
2050 IP address of the physical interface on the machine which will be
2051 servicing the requests. If you have multiple name-based hosts on
2052 multiple addresses, repeat the directive for each address.</p>
2054 <note><title>Note</title>
2055 <p>Note, that the "main server" and any <code>_default_</code> servers
2056 will <strong>never</strong> be served for a request to a
2057 <directive>NameVirtualHost</directive> IP Address (unless for some
2058 reason you specify <directive>NameVirtualHost</directive> but then
2059 don't define any <directive>VirtualHost</directive>s for that
2063 <p>Optionally you can specify a port number on which the
2064 name-based virtual hosts should be used, e.g.</p>
2067 NameVirtualHost 111.22.33.44:8080
2070 <p>IPv6 addresses must be enclosed in square brackets, as shown
2071 in the following example:</p>
2074 NameVirtualHost [fe80::a00:20ff:fea7:ccea]:8080
2077 <p>To receive requests on all interfaces, you can use an argument of
2084 <note><title>Argument to <directive type="section">VirtualHost</directive>
2086 <p>Note that the argument to the <directive
2087 type="section">VirtualHost</directive> directive must
2088 exactly match the argument to the <directive
2089 >NameVirtualHost</directive> directive.</p>
2092 NameVirtualHost 1.2.3.4<br />
2093 <VirtualHost 1.2.3.4><br />
2095 </VirtualHost><br />
2100 <seealso><a href="../vhosts/">Virtual Hosts
2101 documentation</a></seealso>
2103 </directivesynopsis>
2106 <name>Options</name>
2107 <description>Configures what features are available in a particular
2108 directory</description>
2110 [+|-]<var>option</var> [[+|-]<var>option</var>] ...</syntax>
2111 <default>Options All</default>
2112 <contextlist><context>server config</context><context>virtual host</context>
2113 <context>directory</context><context>.htaccess</context>
2115 <override>Options</override>
2118 <p>The <directive>Options</directive> directive controls which
2119 server features are available in a particular directory.</p>
2121 <p><var>option</var> can be set to <code>None</code>, in which
2122 case none of the extra features are enabled, or one or more of
2126 <dt><code>All</code></dt>
2128 <dd>All options except for <code>MultiViews</code>. This is the default
2131 <dt><code>ExecCGI</code></dt>
2134 Execution of CGI scripts using <module>mod_cgi</module>
2137 <dt><code>FollowSymLinks</code></dt>
2141 The server will follow symbolic links in this directory.
2143 <p>Even though the server follows the symlink it does <em>not</em>
2144 change the pathname used to match against <directive type="section"
2145 module="core">Directory</directive> sections.</p>
2146 <p>Note also, that this option <strong>gets ignored</strong> if set
2147 inside a <directive type="section" module="core">Location</directive>
2151 <dt><code>Includes</code></dt>
2154 Server-side includes provided by <module>mod_include</module>
2157 <dt><code>IncludesNOEXEC</code></dt>
2161 Server-side includes are permitted, but the <code>#exec
2162 cmd</code> and <code>#exec cgi</code> are disabled. It is still
2163 possible to <code>#include virtual</code> CGI scripts from
2164 <directive module="mod_alias">ScriptAlias</directive>ed
2167 <dt><code>Indexes</code></dt>
2170 If a URL which maps to a directory is requested, and there
2171 is no <directive module="mod_dir">DirectoryIndex</directive>
2172 (<em>e.g.</em>, <code>index.html</code>) in that directory, then
2173 <module>mod_autoindex</module> will return a formatted listing
2174 of the directory.</dd>
2176 <dt><code>MultiViews</code></dt>
2179 <a href="../content-negotiation.html">Content negotiated</a>
2180 "MultiViews" are allowed using
2181 <module>mod_negotiation</module>.</dd>
2183 <dt><code>SymLinksIfOwnerMatch</code></dt>
2185 <dd>The server will only follow symbolic links for which the
2186 target file or directory is owned by the same user id as the
2189 <note><title>Note</title> This option gets ignored if
2190 set inside a <directive module="core"
2191 type="section">Location</directive> section.</note>
2195 <p>Normally, if multiple <directive>Options</directive> could
2196 apply to a directory, then the most specific one is used and
2197 others are ignored; the options are not merged. (See <a
2198 href="../sections.html#mergin">how sections are merged</a>.)
2199 However if <em>all</em> the options on the
2200 <directive>Options</directive> directive are preceded by a
2201 <code>+</code> or <code>-</code> symbol, the options are
2202 merged. Any options preceded by a <code>+</code> are added to the
2203 options currently in force, and any options preceded by a
2204 <code>-</code> are removed from the options currently in
2207 <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>
2210 <Directory /web/docs><br />
2212 Options Indexes FollowSymLinks<br />
2214 </Directory><br />
2216 <Directory /web/docs/spec><br />
2218 Options Includes<br />
2223 <p>then only <code>Includes</code> will be set for the
2224 <code>/web/docs/spec</code> directory. However if the second
2225 <directive>Options</directive> directive uses the <code>+</code> and
2226 <code>-</code> symbols:</p>
2229 <Directory /web/docs><br />
2231 Options Indexes FollowSymLinks<br />
2233 </Directory><br />
2235 <Directory /web/docs/spec><br />
2237 Options +Includes -Indexes<br />
2242 <p>then the options <code>FollowSymLinks</code> and
2243 <code>Includes</code> are set for the <code>/web/docs/spec</code>
2246 <note><title>Note</title>
2247 <p>Using <code>-IncludesNOEXEC</code> or
2248 <code>-Includes</code> disables server-side includes completely
2249 regardless of the previous setting.</p>
2252 <p>The default in the absence of any other settings is
2253 <code>All</code>.</p>
2255 </directivesynopsis>
2258 <name>Require</name>
2259 <description>Selects which authenticated users can access
2260 a resource</description>
2261 <syntax>Require <var>entity-name</var> [<var>entity-name</var>] ...</syntax>
2262 <contextlist><context>directory</context><context>.htaccess</context>
2264 <override>AuthConfig</override>
2267 <p>This directive selects which authenticated users can access
2268 a directory. The allowed syntaxes are:</p>
2271 <dt><code>Require user <var>userid</var> [<var>userid</var>]
2273 <dd>Only the named users can access the resource.</dd>
2275 <dt><code>Require group <var>group-name</var> [<var>group-name</var>]
2277 <dd>Only users in the named groups can access the resource.</dd>
2279 <dt><code>Require valid-user</code></dt>
2280 <dd>All valid users can access the resource.</dd>
2283 <p><directive>Require</directive> must be accompanied by
2284 <directive module="core">AuthName</directive> and <directive
2285 module="core">AuthType</directive> directives, and directives such
2286 as <directive module="mod_authn_file">AuthUserFile</directive>
2287 and <directive module="mod_authz_groupfile">AuthGroupFile</directive> (to
2288 define users and groups) in order to work correctly. Example:</p>
2291 AuthType Basic<br />
2292 AuthName "Restricted Directory"<br />
2293 AuthUserFile /web/users<br />
2294 AuthGroupFile /web/groups<br />
2298 <p>Access controls which are applied in this way are effective for
2299 <strong>all</strong> methods. <strong>This is what is normally
2300 desired.</strong> If you wish to apply access controls only to
2301 specific methods, while leaving other methods unprotected, then
2302 place the <directive>Require</directive> statement into a
2303 <directive module="core" type="section">Limit</directive>
2306 <seealso><directive module="core">Satisfy</directive></seealso>
2307 <seealso><module>mod_authz_host</module></seealso>
2308 </directivesynopsis>
2311 <name>RLimitCPU</name>
2312 <description>Limits the CPU consumption of processes launched
2313 by Apache children</description>
2314 <syntax>RLimitCPU <var>seconds</var>|max [<var>seconds</var>|max]</syntax>
2315 <default>Unset; uses operating system defaults</default>
2316 <contextlist><context>server config</context><context>virtual host</context>
2317 <context>directory</context><context>.htaccess</context></contextlist>
2318 <override>All</override>
2321 <p>Takes 1 or 2 parameters. The first parameter sets the soft
2322 resource limit for all processes and the second parameter sets
2323 the maximum resource limit. Either parameter can be a number,
2324 or <code>max</code> to indicate to the server that the limit should
2325 be set to the maximum allowed by the operating system
2326 configuration. Raising the maximum resource limit requires that
2327 the server is running as <code>root</code>, or in the initial startup
2330 <p>This applies to processes forked off from Apache children
2331 servicing requests, not the Apache children themselves. This
2332 includes CGI scripts and SSI exec commands, but not any
2333 processes forked off from the Apache parent such as piped
2336 <p>CPU resource limits are expressed in seconds per
2339 <seealso><directive module="core">RLimitMEM</directive></seealso>
2340 <seealso><directive module="core">RLimitNPROC</directive></seealso>
2341 </directivesynopsis>
2344 <name>RLimitMEM</name>
2345 <description>Limits the memory consumption of processes launched
2346 by Apache children</description>
2347 <syntax>RLimitMEM <var>bytes</var>|max [<var>bytes</var>|max]</syntax>
2348 <default>Unset; uses operating system defaults</default>
2349 <contextlist><context>server config</context><context>virtual host</context>
2350 <context>directory</context><context>.htaccess</context></contextlist>
2351 <override>All</override>
2354 <p>Takes 1 or 2 parameters. The first parameter sets the soft
2355 resource limit for all processes and the second parameter sets
2356 the maximum resource limit. Either parameter can be a number,
2357 or <code>max</code> to indicate to the server that the limit should
2358 be set to the maximum allowed by the operating system
2359 configuration. Raising the maximum resource limit requires that
2360 the server is running as <code>root</code>, or in the initial startup
2363 <p>This applies to processes forked off from Apache children
2364 servicing requests, not the Apache children themselves. This
2365 includes CGI scripts and SSI exec commands, but not any
2366 processes forked off from the Apache parent such as piped
2369 <p>Memory resource limits are expressed in bytes per
2372 <seealso><directive module="core">RLimitCPU</directive></seealso>
2373 <seealso><directive module="core">RLimitNPROC</directive></seealso>
2374 </directivesynopsis>
2377 <name>RLimitNPROC</name>
2378 <description>Limits the number of processes that can be launched by
2379 processes launched by Apache children</description>
2380 <syntax>RLimitNPROC <var>number</var>|max [<var>number</var>|max]</syntax>
2381 <default>Unset; uses operating system defaults</default>
2382 <contextlist><context>server config</context><context>virtual host</context>
2383 <context>directory</context><context>.htaccess</context></contextlist>
2384 <override>All</override>
2387 <p>Takes 1 or 2 parameters. The first parameter sets the soft
2388 resource limit for all processes and the second parameter sets
2389 the maximum resource limit. Either parameter can be a number,
2390 or <code>max</code> to indicate to the server that the limit
2391 should be set to the maximum allowed by the operating system
2392 configuration. Raising the maximum resource limit requires that
2393 the server is running as <code>root</code>, or in the initial startup
2396 <p>This applies to processes forked off from Apache children
2397 servicing requests, not the Apache children themselves. This
2398 includes CGI scripts and SSI exec commands, but not any
2399 processes forked off from the Apache parent such as piped
2402 <p>Process limits control the number of processes per user.</p>
2404 <note><title>Note</title>
2405 <p>If CGI processes are <strong>not</strong> running
2406 under userids other than the web server userid, this directive
2407 will limit the number of processes that the server itself can
2408 create. Evidence of this situation will be indicated by
2409 <strong><code>cannot fork</code></strong> messages in the
2410 <code>error_log</code>.</p>
2413 <seealso><directive module="core">RLimitMEM</directive></seealso>
2414 <seealso><directive module="core">RLimitCPU</directive></seealso>
2415 </directivesynopsis>
2418 <name>Satisfy</name>
2419 <description>Interaction between host-level access control and
2420 user authentication</description>
2421 <syntax>Satisfy Any|All</syntax>
2422 <default>Satisfy All</default>
2423 <contextlist><context>directory</context><context>.htaccess</context>
2425 <override>AuthConfig</override>
2428 <p>Access policy if both <directive
2429 module="mod_authz_host">Allow</directive> and <directive
2430 module="core">Require</directive> used. The parameter can be
2431 either <code>All</code> or <code>Any</code>. This directive is only
2432 useful if access to a particular area is being restricted by both
2433 username/password <em>and</em> client host address. In this case
2434 the default behavior (<code>All</code>) is to require that the client
2435 passes the address access restriction <em>and</em> enters a valid
2436 username and password. With the <code>Any</code> option the client will be
2437 granted access if they either pass the host restriction or enter a
2438 valid username and password. This can be used to password restrict
2439 an area, but to let clients from particular addresses in without
2440 prompting for a password.</p>
2442 <p>For example, if you wanted to let people on your network have
2443 unrestricted access to a portion of your website, but require that
2444 people outside of your network provide a password, you could use a
2445 configuration similar to the following:</p>
2448 Require valid-user<br />
2449 Allow from 192.168.1<br />
2454 <seealso><directive module="mod_authz_host">Allow</directive></seealso>
2455 <seealso><directive module="core">Require</directive></seealso>
2456 </directivesynopsis>
2459 <name>ScriptInterpreterSource</name>
2460 <description>Technique for locating the interpreter for CGI
2461 scripts</description>
2462 <syntax>ScriptInterpreterSource Registry|Registry-Strict|Script</syntax>
2463 <default>ScriptInterpreterSource Script</default>
2464 <contextlist><context>server config</context><context>virtual host</context>
2465 <context>directory</context><context>.htaccess</context></contextlist>
2466 <override>FileInfo</override>
2467 <compatibility>Win32 only;
2468 option <code>Registry-Strict</code> is available in Apache 2.0 and
2469 later</compatibility>
2472 <p>This directive is used to control how Apache finds the
2473 interpreter used to run CGI scripts. The default setting is
2474 <code>Script</code>. This causes Apache to use the interpreter pointed to
2475 by the shebang line (first line, starting with <code>#!</code>) in the
2476 script. On Win32 systems this line usually looks like:</p>
2479 #!C:/Perl/bin/perl.exe
2482 <p>or, if perl is in the <code>PATH</code>, simply:</p>
2488 <p>Setting <code>ScriptInterpreterSource Registry</code> will
2489 cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
2490 searched using the script file extension (e.g., <code>.pl</code>) as a
2491 search key. The command defined by the registry subkey
2492 <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
2493 <code>Shell\Open\Command</code> is used to open the script file. If the
2494 registry keys cannot be found, Apache falls back to the behavior of the
2495 <code>Script</code> option.</p>
2497 <note type="warning"><title>Security</title>
2498 <p>Be careful when using <code>ScriptInterpreterSource
2499 Registry</code> with <directive
2500 module="mod_alias">ScriptAlias</directive>'ed directories, because
2501 Apache will try to execute <strong>every</strong> file within this
2502 directory. The <code>Registry</code> setting may cause undesired
2503 program calls on files which are typically not executed. For
2504 example, the default open command on <code>.htm</code> files on
2505 most Windows systems will execute Microsoft Internet Explorer, so
2506 any HTTP request for an <code>.htm</code> file existing within the
2507 script directory would start the browser in the background on the
2508 server. This is a good way to crash your system within a minute or
2512 <p>The option <code>Registry-Strict</code> which is new in Apache
2513 2.0 does the same thing as <code>Registry</code> but uses only the
2514 subkey <code>Shell\ExecCGI\Command</code>. The
2515 <code>ExecCGI</code> key is not a common one. It must be
2516 configured manually in the windows registry and hence prevents
2517 accidental program calls on your system.</p>
2519 </directivesynopsis>
2522 <name>ServerAdmin</name>
2523 <description>Email address that the server includes in error
2524 messages sent to the client</description>
2525 <syntax>ServerAdmin <var>email-address</var></syntax>
2526 <contextlist><context>server config</context><context>virtual host</context>
2530 <p>The <directive>ServerAdmin</directive> sets the e-mail address
2531 that the server includes in any error messages it returns to the
2534 <p>It may be worth setting up a dedicated address for this, e.g.</p>
2537 ServerAdmin www-admin@foo.example.com
2539 <p>as users do not always mention that they are talking about the
2542 </directivesynopsis>
2545 <name>ServerAlias</name>
2546 <description>Alternate names for a host used when matching requests
2547 to name-virtual hosts</description>
2548 <syntax>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</syntax>
2549 <contextlist><context>virtual host</context></contextlist>
2552 <p>The <directive>ServerAlias</directive> directive sets the
2553 alternate names for a host, for use with <a
2554 href="../vhosts/name-based.html">name-based virtual hosts</a>.</p>
2557 <VirtualHost *><br />
2558 ServerName server.domain.com<br />
2559 ServerAlias server server2.domain.com server2<br />
2561 </VirtualHost>
2564 <seealso><a href="../vhosts/">Apache Virtual Host documentation</a></seealso>
2565 </directivesynopsis>
2568 <name>ServerName</name>
2569 <description>Hostname and port that the server uses to identify
2570 itself</description>
2571 <syntax>ServerName <var>fully-qualified-domain-name</var>[:<var>port</var>]</syntax>
2572 <contextlist><context>server config</context><context>virtual host</context>
2574 <compatibility>In version 2.0, this
2575 directive supersedes the functionality of the <directive>Port</directive>
2576 directive from version 1.3.</compatibility>
2579 <p>The <directive>ServerName</directive> directive sets the hostname and
2580 port that the server uses to identify itself. This is used when
2581 creating redirection URLs. For example, if the name of the
2582 machine hosting the webserver is <code>simple.example.com</code>,
2583 but the machine also has the DNS alias <code>www.example.com</code>
2584 and you wish the webserver to be so identified, the following
2585 directive should be used:</p>
2588 ServerName www.example.com:80
2591 <p>If no <directive>ServerName</directive> is specified, then the
2592 server attempts to deduce the hostname by performing a reverse
2593 lookup on the IP address. If no port is specified in the
2594 servername, then the server will use the port from the incoming
2595 request. For optimal reliability and predictability, you should
2596 specify an explicit hostname and port using the
2597 <directive>ServerName</directive> directive.</p>
2599 <p>If you are using <a
2600 href="../vhosts/name-based.html">name-based virtual hosts</a>,
2601 the <directive>ServerName</directive> inside a
2602 <directive type="section" module="core">VirtualHost</directive>
2603 section specifies what hostname must appear in the request's
2604 <code>Host:</code> header to match this virtual host.</p>
2606 <p>See the description of the
2607 <directive module="core">UseCanonicalName</directive> directive for
2608 settings which determine whether self-referential URL's (e.g., by the
2609 <module>mod_dir</module> module) will refer to the
2610 specified port, or to the port number given in the client's request.
2614 <seealso><a href="../dns-caveats.html">Issues Regarding DNS and
2615 Apache</a></seealso>
2616 <seealso><a href="../vhosts/">Apache virtual host
2617 documentation</a></seealso>
2618 <seealso><directive module="core">UseCanonicalName</directive></seealso>
2619 <seealso><directive module="core">NameVirtualHost</directive></seealso>
2620 <seealso><directive module="core">ServerAlias</directive></seealso>
2621 </directivesynopsis>
2624 <name>ServerPath</name>
2625 <description>Legacy URL pathname for a name-based virtual host that
2626 is accessed by an incompatible browser</description>
2627 <syntax>ServerPath <var>URL-path</var></syntax>
2628 <contextlist><context>virtual host</context></contextlist>
2631 <p>The <directive>ServerPath</directive> directive sets the legacy
2632 URL pathname for a host, for use with <a
2633 href="../vhosts/">name-based virtual hosts</a>.</p>
2635 <seealso><a href="../vhosts/">Apache Virtual Host documentation</a></seealso>
2636 </directivesynopsis>
2639 <name>ServerRoot</name>
2640 <description>Base directory for the server installation</description>
2641 <syntax>ServerRoot <var>directory-path</var></syntax>
2642 <default>ServerRoot /usr/local/apache</default>
2643 <contextlist><context>server config</context></contextlist>
2646 <p>The <directive>ServerRoot</directive> directive sets the
2647 directory in which the server lives. Typically it will contain the
2648 subdirectories <code>conf/</code> and <code>logs/</code>. Relative
2649 paths for other configuration files are taken as relative to this
2652 <example><title>Example</title>
2653 ServerRoot /home/httpd
2657 <seealso><a href="../invoking.html">the <code>-d</code>
2658 option to <code>httpd</code></a></seealso>
2659 <seealso><a href="../misc/security_tips.html#serverroot">the
2660 security tips</a> for information on how to properly set
2661 permissions on the <directive>ServerRoot</directive></seealso>
2662 </directivesynopsis>
2665 <name>ServerSignature</name>
2666 <description>Configures the footer on server-generated documents</description>
2667 <syntax>ServerSignature On|Off|EMail</syntax>
2668 <default>ServerSignature Off</default>
2669 <contextlist><context>server config</context><context>virtual host</context>
2670 <context>directory</context><context>.htaccess</context>
2672 <override>All</override>
2675 <p>The <directive>ServerSignature</directive> directive allows the
2676 configuration of a trailing footer line under server-generated
2677 documents (error messages, <module>mod_proxy</module> ftp directory
2678 listings, <module>mod_info</module> output, ...). The reason why you
2679 would want to enable such a footer line is that in a chain of proxies,
2680 the user often has no possibility to tell which of the chained servers
2681 actually produced a returned error message.</p>
2683 <p>The <code>Off</code>
2684 setting, which is the default, suppresses the footer line (and is
2685 therefore compatible with the behavior of Apache-1.2 and
2686 below). The <code>On</code> setting simply adds a line with the
2687 server version number and <directive
2688 module="core">ServerName</directive> of the serving virtual host,
2689 and the <code>EMail</code> setting additionally creates a
2690 "mailto:" reference to the <directive
2691 module="core">ServerAdmin</directive> of the referenced
2694 <p>After version 2.0.44, the details of the server version number
2695 presented are controlled by the <directive
2696 module="core">ServerTokens</directive> directive.</p>
2698 <seealso><directive module="core">ServerTokens</directive></seealso>
2699 </directivesynopsis>
2702 <name>ServerTokens</name>
2703 <description>Configures the <code>Server</code> HTTP response
2704 header</description>
2705 <syntax>ServerTokens Major|Minor|Min[imal]|Prod[uctOnly]|OS|Full</syntax>
2706 <default>ServerTokens Full</default>
2707 <contextlist><context>server config</context></contextlist>
2710 <p>This directive controls whether <code>Server</code> response
2711 header field which is sent back to clients includes a
2712 description of the generic OS-type of the server as well as
2713 information about compiled-in modules.</p>
2716 <dt><code>ServerTokens Prod[uctOnly]</code></dt>
2718 <dd>Server sends (<em>e.g.</em>): <code>Server:
2721 <dt><code>ServerTokens Major</code></dt>
2723 <dd>Server sends (<em>e.g.</em>): <code>Server:
2724 Apache/2</code></dd>
2726 <dt><code>ServerTokens Minor</code></dt>
2728 <dd>Server sends (<em>e.g.</em>): <code>Server:
2729 Apache/2.0</code></dd>
2731 <dt><code>ServerTokens Min[imal]</code></dt>
2733 <dd>Server sends (<em>e.g.</em>): <code>Server:
2734 Apache/2.0.41</code></dd>
2736 <dt><code>ServerTokens OS</code></dt>
2738 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.0.41
2741 <dt><code>ServerTokens Full</code> (or not specified)</dt>
2743 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.0.41
2744 (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
2747 <p>This setting applies to the entire server, and cannot be
2748 enabled or disabled on a virtualhost-by-virtualhost basis.</p>
2750 <p>After version 2.0.44, this directive also controls the
2751 information presented by the <directive
2752 module="core">ServerSignature</directive> directive.</p>
2754 <seealso><directive module="core">ServerSignature</directive></seealso>
2755 </directivesynopsis>
2758 <name>SetHandler</name>
2759 <description>Forces all matching files to be processed by a
2760 handler</description>
2761 <syntax>SetHandler <var>handler-name</var>|None</syntax>
2762 <contextlist><context>server config</context><context>virtual host</context>
2763 <context>directory</context><context>.htaccess</context>
2765 <override>FileInfo</override>
2766 <compatibility>Moved into the core in Apache 2.0</compatibility>
2769 <p>When placed into an <code>.htaccess</code> file or a
2770 <directive type="section" module="core">Directory</directive> or
2771 <directive type="section" module="core">Location</directive>
2772 section, this directive forces all matching files to be parsed
2773 through the <a href="../handler.html">handler</a> given by
2774 <var>handler-name</var>. For example, if you had a directory you
2775 wanted to be parsed entirely as imagemap rule files, regardless
2776 of extension, you might put the following into an
2777 <code>.htaccess</code> file in that directory:</p>
2780 SetHandler imap-file
2783 <p>Another example: if you wanted to have the server display a
2784 status report whenever a URL of
2785 <code>http://servername/status</code> was called, you might put
2786 the following into <code>httpd.conf</code>:</p>
2789 <Location /status><br />
2791 SetHandler server-status<br />
2796 <p>You can override an earlier defined <directive>SetHandler</directive>
2797 directive by using the value <code>None</code>.</p>
2800 <seealso><directive module="mod_mime">AddHandler</directive></seealso>
2802 </directivesynopsis>
2805 <name>SetInputFilter</name>
2806 <description>Sets the filters that will process client requests and POST
2808 <syntax>SetInputFilter <var>filter</var>[;<var>filter</var>...]</syntax>
2809 <contextlist><context>server config</context><context>virtual host</context>
2810 <context>directory</context><context>.htaccess</context>
2812 <override>FileInfo</override>
2815 <p>The <directive>SetInputFilter</directive> directive sets the
2816 filter or filters which will process client requests and POST
2817 input when they are received by the server. This is in addition to
2818 any filters defined elsewhere, including the
2819 <directive module="mod_mime">AddInputFilter</directive>
2822 <p>If more than one filter is specified, they must be separated
2823 by semicolons in the order in which they should process the
2826 <seealso><a href="../filter.html">Filters</a> documentation</seealso>
2827 </directivesynopsis>
2830 <name>SetOutputFilter</name>
2831 <description>Sets the filters that will process responses from the
2832 server</description>
2833 <syntax>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</syntax>
2834 <contextlist><context>server config</context><context>virtual host</context>
2835 <context>directory</context><context>.htaccess</context>
2837 <override>FileInfo</override>
2840 <p>The <directive>SetOutputFilter</directive> directive sets the filters
2841 which will process responses from the server before they are
2842 sent to the client. This is in addition to any filters defined
2843 elsewhere, including the
2844 <directive module="mod_mime">AddOutputFilter</directive>
2847 <p>For example, the following configuration will process all files
2848 in the <code>/www/data/</code> directory for server-side
2852 <Directory /www/data/><br />
2854 SetOutputFilter INCLUDES<br />
2859 <p>If more than one filter is specified, they must be separated
2860 by semicolons in the order in which they should process the
2863 <seealso><a href="../filter.html">Filters</a> documentation</seealso>
2864 </directivesynopsis>
2867 <name>TimeOut</name>
2868 <description>Amount of time the server will wait for
2869 certain events before failing a request</description>
2870 <syntax>TimeOut <var>seconds</var></syntax>
2871 <default>TimeOut 300</default>
2872 <contextlist><context>server config</context></contextlist>
2875 <p>The <directive>TimeOut</directive> directive currently defines
2876 the amount of time Apache will wait for three things:</p>
2879 <li>The total amount of time it takes to receive a GET
2882 <li>The amount of time between receipt of TCP packets on a
2883 POST or PUT request.</li>
2885 <li>The amount of time between ACKs on transmissions of TCP
2886 packets in responses.</li>
2889 <p>We plan on making these separately configurable at some point
2890 down the road. The timer used to default to 1200 before 1.2,
2891 but has been lowered to 300 which is still far more than
2892 necessary in most situations. It is not set any lower by
2893 default because there may still be odd places in the code where
2894 the timer is not reset when a packet is sent. </p>
2896 </directivesynopsis>
2899 <name>UseCanonicalName</name>
2900 <description>Configures how the server determines its own name and
2902 <syntax>UseCanonicalName On|Off|DNS</syntax>
2903 <default>UseCanonicalName On</default>
2904 <contextlist><context>server config</context><context>virtual host</context>
2905 <context>directory</context></contextlist>
2908 <p>In many situations Apache must construct a <em>self-referential</em>
2909 URL -- that is, a URL that refers back to the same server. With
2910 <code>UseCanonicalName On</code> Apache will use the hostname and port
2911 specified in the <directive module="core">ServerName</directive>
2912 directive to construct the canonical name for the server. This name
2913 is used in all self-referential URLs, and for the values of
2914 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>
2916 <p>With <code>UseCanonicalName Off</code> Apache will form
2917 self-referential URLs using the hostname and port supplied by
2918 the client if any are supplied (otherwise it will use the
2919 canonical name, as defined above). These values are the same
2920 that are used to implement <a
2921 href="../vhosts/name-based.html">name based virtual hosts</a>,
2922 and are available with the same clients. The CGI variables
2923 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
2924 constructed from the client supplied values as well.</p>
2926 <p>An example where this may be useful is on an intranet server
2927 where you have users connecting to the machine using short
2928 names such as <code>www</code>. You'll notice that if the users
2929 type a shortname, and a URL which is a directory, such as
2930 <code>http://www/splat</code>, <em>without the trailing
2931 slash</em> then Apache will redirect them to
2932 <code>http://www.domain.com/splat/</code>. If you have
2933 authentication enabled, this will cause the user to have to
2934 authenticate twice (once for <code>www</code> and once again
2935 for <code>www.domain.com</code> -- see <a
2936 href="http://httpd.apache.org/docs/misc/FAQ.html#prompted-twice">the
2937 FAQ on this subject for more information</a>). But if
2938 <directive>UseCanonicalName</directive> is set <code>Off</code>, then
2939 Apache will redirect to <code>http://www/splat/</code>.</p>
2941 <p>There is a third option, <code>UseCanonicalName DNS</code>,
2942 which is intended for use with mass IP-based virtual hosting to
2943 support ancient clients that do not provide a
2944 <code>Host:</code> header. With this option Apache does a
2945 reverse DNS lookup on the server IP address that the client
2946 connected to in order to work out self-referential URLs.</p>
2948 <note type="warning"><title>Warning</title>
2949 <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>
2950 they may be broken by this option. The client is essentially free
2951 to give whatever value they want as a hostname. But if the CGI is
2952 only using <code>SERVER_NAME</code> to construct self-referential URLs
2953 then it should be just fine.</p>
2956 <seealso><directive module="core">ServerName</directive></seealso>
2957 <seealso><directive module="mpm_common">Listen</directive></seealso>
2958 </directivesynopsis>
2960 <directivesynopsis type="section">
2961 <name>VirtualHost</name>
2962 <description>Contains directives that apply only to a specific
2963 hostname or IP address</description>
2964 <syntax><VirtualHost
2965 <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
2966 ...> ... </VirtualHost></syntax>
2967 <contextlist><context>server config</context></contextlist>
2970 <p><directive type="section">VirtualHost</directive> and
2971 <code></VirtualHost></code> are used to enclose a group of
2972 directives that will apply only to a particular virtual host. Any
2973 directive that is allowed in a virtual host context may be
2974 used. When the server receives a request for a document on a
2975 particular virtual host, it uses the configuration directives
2976 enclosed in the <directive type="section">VirtualHost</directive>
2977 section. <var>Addr</var> can be:</p>
2980 <li>The IP address of the virtual host;</li>
2982 <li>A fully qualified domain name for the IP address of the
2985 <li>The character <code>*</code>, which is used only in combination with
2986 <code>NameVirtualHost *</code> to match all IP addresses; or</li>
2988 <li>The string <code>_default_</code>, which is used only
2989 with IP virtual hosting to catch unmatched IP addresses.</li>
2992 <example><title>Example</title>
2993 <VirtualHost 10.1.2.3><br />
2995 ServerAdmin webmaster@host.foo.com<br />
2996 DocumentRoot /www/docs/host.foo.com<br />
2997 ServerName host.foo.com<br />
2998 ErrorLog logs/host.foo.com-error_log<br />
2999 TransferLog logs/host.foo.com-access_log<br />
3001 </VirtualHost>
3005 <p>IPv6 addresses must be specified in square brackets because
3006 the optional port number could not be determined otherwise. An
3007 IPv6 example is shown below:</p>
3010 <VirtualHost [fe80::a00:20ff:fea7:ccea]><br />
3012 ServerAdmin webmaster@host.example.com<br />
3013 DocumentRoot /www/docs/host.example.com<br />
3014 ServerName host.example.com<br />
3015 ErrorLog logs/host.example.com-error_log<br />
3016 TransferLog logs/host.example.com-access_log<br />
3018 </VirtualHost>
3021 <p>Each Virtual Host must correspond to a different IP address,
3022 different port number or a different host name for the server,
3023 in the former case the server machine must be configured to
3024 accept IP packets for multiple addresses. (If the machine does
3025 not have multiple network interfaces, then this can be
3026 accomplished with the <code>ifconfig alias</code> command -- if
3027 your OS supports it).</p>
3029 <note><title>Note</title>
3030 <p>The use of <directive type="section">VirtualHost</directive> does
3031 <strong>not</strong> affect what addresses Apache listens on. You
3032 may need to ensure that Apache is listening on the correct addresses
3033 using <directive module="mpm_common">Listen</directive>.</p>
3036 <p>When using IP-based virtual hosting, the special name
3037 <code>_default_</code> can be specified in
3038 which case this virtual host will match any IP address that is
3039 not explicitly listed in another virtual host. In the absence
3040 of any <code>_default_</code> virtual host the "main" server config,
3041 consisting of all those definitions outside any VirtualHost
3042 section, is used when no IP-match occurs. (But note that any IP
3043 address that matches a <directive
3044 module="core">NameVirtualHost</directive> directive will use neither
3045 the "main" server config nor the <code>_default_</code> virtual host.
3046 See the <a href="../vhosts/name-based.html">name-based virtual hosting</a>
3047 documentation for further details.)</p>
3049 <p>You can specify a <code>:port</code> to change the port that is
3050 matched. If unspecified then it defaults to the same port as the
3051 most recent <directive module="mpm_common">Listen</directive>
3052 statement of the main server. You may also specify <code>:*</code>
3053 to match all ports on that address. (This is recommended when used
3054 with <code>_default_</code>.)</p>
3056 <note type="warning"><title>Security</title>
3057 <p>See the <a href="../misc/security_tips.html">security tips</a>
3058 document for details on why your security could be compromised if the
3059 directory where logfiles are stored is writable by anyone other
3060 than the user that starts the server.</p>
3063 <seealso><a href="../vhosts/">Apache Virtual Host documentation</a></seealso>
3064 <seealso><a href="../dns-caveats.html">Issues Regarding DNS and
3065 Apache</a></seealso>
3066 <seealso><a href="../bind.html">Setting
3067 which addresses and ports Apache uses</a></seealso>
3068 <seealso><a href="../sections.html">How <Directory>, <Location>
3069 and <Files> sections work</a> for an explanation of how these
3070 different sections are combined when a request is received</seealso>
3071 </directivesynopsis>