2 <!DOCTYPE modulesynopsis SYSTEM "../style/modulesynopsis.dtd">
3 <?xml-stylesheet type="text/xsl" href="../style/manual.en.xsl"?>
4 <!-- $LastChangedRevision$ -->
7 Copyright 2002-2005 The Apache Software Foundation or its licensors, as
10 Licensed under the Apache License, Version 2.0 (the "License");
11 you may not use this file except in compliance with the License.
12 You may obtain a copy of the License at
14 http://www.apache.org/licenses/LICENSE-2.0
16 Unless required by applicable law or agreed to in writing, software
17 distributed under the License is distributed on an "AS IS" BASIS,
18 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19 See the License for the specific language governing permissions and
20 limitations under the License.
23 <modulesynopsis metafile="core.xml.meta">
26 <description>Core Apache HTTP Server features that are always
27 available</description>
31 <name>AcceptFilter</name>
32 <description>Configures optimizations for a Protocol's Listener Sockets</description>
33 <syntax>AcceptFilter <var>protocol</var> <var>accept_filter</var></syntax>
34 <contextlist><context>server config</context></contextlist>
35 <compatibility>Available in Apache 2.1.5 and later</compatibility>
38 <p>This directive enables operating system specific optimizations for a
39 listening socket by the Protocol type. The basic premise is for the
40 kernel to not send a socket to the server process until either data
41 is received or an entire HTTP Request is buffered. Only
42 <a href="http://www.freebsd.org/cgi/man.cgi?query=accept_filter&sektion=9">
43 FreeBSD's Accept Filters</a> and Linux's more primitive
44 <code>TCP_DEFER_ACCEPT</code> are currently supported.</p>
46 <p>The default values on FreeBSD are:</p>
48 AcceptFilter http httpready <br/>
49 AcceptFilter https dataready
52 <p>The <code>httpready</code> accept filter buffers entire HTTP requests at
53 the kernel level. Once an entire request is recieved, the kernel then
54 sends it to the server. See the
55 <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_http&sektion=9">
56 accf_http(9)</a> man page for more details. Since HTTPS requests are
57 encrypted only the <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_data&sektion=9">
58 accf_data(9)</a> filter is used.</p>
60 <p>The default values on Linux are:</p>
62 AcceptFilter http data <br/>
63 AcceptFilter https data
66 <p>Linux's <code>TCP_DEFER_ACCEPT</code> does not support buffering http
67 requests. Any value besides <code>none</code> will enable
68 <code>TCP_DEFER_ACCEPT</code> on that listener. For more details
70 <a href="http://homepages.cwi.nl/~aeb/linux/man2html/man7/tcp.7.html">
71 tcp(7)</a> man page.</p>
73 <p>Using <code>none</code> for an argument will disable any accept filters
74 for that protocol. This is useful for protocols that require a server
75 send data first, such as <code>nntp</code>:</p>
76 <example>AcceptFilter nttp none</example>
82 <name>AcceptPathInfo</name>
83 <description>Resources accept trailing pathname information</description>
84 <syntax>AcceptPathInfo On|Off|Default</syntax>
85 <default>AcceptPathInfo Default</default>
86 <contextlist><context>server config</context>
87 <context>virtual host</context><context>directory</context>
88 <context>.htaccess</context></contextlist>
89 <override>FileInfo</override>
90 <compatibility>Available in Apache 2.0.30 and later</compatibility>
94 <p>This directive controls whether requests that contain trailing
95 pathname information that follows an actual filename (or
96 non-existent file in an existing directory) will be accepted or
97 rejected. The trailing pathname information can be made
98 available to scripts in the <code>PATH_INFO</code> environment
101 <p>For example, assume the location <code>/test/</code> points to
102 a directory that contains only the single file
103 <code>here.html</code>. Then requests for
104 <code>/test/here.html/more</code> and
105 <code>/test/nothere.html/more</code> both collect
106 <code>/more</code> as <code>PATH_INFO</code>.</p>
108 <p>The three possible arguments for the
109 <directive>AcceptPathInfo</directive> directive are:</p>
111 <dt><code>Off</code></dt><dd>A request will only be accepted if it
112 maps to a literal path that exists. Therefore a request with
113 trailing pathname information after the true filename such as
114 <code>/test/here.html/more</code> in the above example will return
115 a 404 NOT FOUND error.</dd>
117 <dt><code>On</code></dt><dd>A request will be accepted if a
118 leading path component maps to a file that exists. The above
119 example <code>/test/here.html/more</code> will be accepted if
120 <code>/test/here.html</code> maps to a valid file.</dd>
122 <dt><code>Default</code></dt><dd>The treatment of requests with
123 trailing pathname information is determined by the <a
124 href="../handler.html">handler</a> responsible for the request.
125 The core handler for normal files defaults to rejecting
126 <code>PATH_INFO</code> requests. Handlers that serve scripts, such as <a
127 href="mod_cgi.html">cgi-script</a> and <a
128 href="mod_isapi.html">isapi-isa</a>, generally accept
129 <code>PATH_INFO</code> by default.</dd>
132 <p>The primary purpose of the <code>AcceptPathInfo</code>
133 directive is to allow you to override the handler's choice of
134 accepting or rejecting <code>PATH_INFO</code>. This override is required,
135 for example, when you use a <a href="../filter.html">filter</a>, such
136 as <a href="mod_include.html">INCLUDES</a>, to generate content
137 based on <code>PATH_INFO</code>. The core handler would usually reject
138 the request, so you can use the following configuration to enable
142 <Files "mypaths.shtml"><br />
144 Options +Includes<br />
145 SetOutputFilter INCLUDES<br />
146 AcceptPathInfo On<br />
155 <name>AccessFileName</name>
156 <description>Name of the distributed configuration file</description>
157 <syntax>AccessFileName <var>filename</var> [<var>filename</var>] ...</syntax>
158 <default>AccessFileName .htaccess</default>
159 <contextlist><context>server config</context><context>virtual host</context>
163 <p>While processing a request the server looks for
164 the first existing configuration file from this list of names in
165 every directory of the path to the document, if distributed
166 configuration files are <a href="#allowoverride">enabled for that
167 directory</a>. For example:</p>
173 <p>before returning the document
174 <code>/usr/local/web/index.html</code>, the server will read
175 <code>/.acl</code>, <code>/usr/.acl</code>,
176 <code>/usr/local/.acl</code> and <code>/usr/local/web/.acl</code>
177 for directives, unless they have been disabled with</p>
180 <Directory /><br />
182 AllowOverride None<br />
187 <seealso><directive module="core">AllowOverride</directive></seealso>
188 <seealso><a href="../configuring.html">Configuration Files</a></seealso>
189 <seealso><a href="../howto/htaccess.html">.htaccess Files</a></seealso>
193 <name>AddDefaultCharset</name>
194 <description>Default charset parameter to be added when a response
195 content-type is <code>text/plain</code> or <code>text/html</code></description>
196 <syntax>AddDefaultCharset On|Off|<var>charset</var></syntax>
197 <default>AddDefaultCharset Off</default>
198 <contextlist><context>server config</context>
199 <context>virtual host</context><context>directory</context>
200 <context>.htaccess</context></contextlist>
201 <override>FileInfo</override>
204 <p>This directive specifies a default value for the media type
205 charset parameter (the name of a character encoding) to be added
206 to a response if and only if the response's content-type is either
207 <code>text/plain</code> or <code>text/html</code>. This should override
208 any charset specified in the body of the response via a <code>META</code>
209 element, though the exact behavior is often dependent on the user's client
210 configuration. A setting of <code>AddDefaultCharset Off</code>
211 disables this functionality. <code>AddDefaultCharset On</code> enables
212 a default charset of <code>iso-8859-1</code>. Any other value is assumed
213 to be the <var>charset</var> to be used, which should be one of the
214 <a href="http://www.iana.org/assignments/character-sets">IANA registered
215 charset values</a> for use in MIME media types.
219 AddDefaultCharset utf-8
222 <p><directive>AddDefaultCharset</directive> should only be used when all
223 of the text resources to which it applies are known to be in that
224 character encoding and it is too inconvenient to label their charset
225 individually. One such example is to add the charset parameter
226 to resources containing generated content, such as legacy CGI
227 scripts, that might be vulnerable to cross-site scripting attacks
228 due to user-provided data being included in the output. Note, however,
229 that a better solution is to just fix (or delete) those scripts, since
230 setting a default charset does not protect users that have enabled
231 the "auto-detect character encoding" feature on their browser.</p>
233 <seealso><directive module="mod_mime">AddCharset</directive></seealso>
237 <name>AddOutputFilterByType</name>
238 <description>assigns an output filter to a particular MIME-type</description>
239 <syntax>AddOutputFilterByType <var>filter</var>[;<var>filter</var>...]
240 <var>MIME-type</var> [<var>MIME-type</var>] ...</syntax>
241 <contextlist><context>server config</context>
242 <context>virtual host</context><context>directory</context>
243 <context>.htaccess</context></contextlist>
244 <override>FileInfo</override>
245 <compatibility>Available in Apache 2.0.33 and later</compatibility>
248 <p>This directive activates a particular output <a
249 href="../filter.html">filter</a> for a request depending on the
250 response <glossary>MIME-type</glossary>.</p>
252 <p>The following example uses the <code>DEFLATE</code> filter, which
253 is provided by <module>mod_deflate</module>. It will compress all
254 output (either static or dynamic) which is labeled as
255 <code>text/html</code> or <code>text/plain</code> before it is sent
259 AddOutputFilterByType DEFLATE text/html text/plain
262 <p>If you want the content to be processed by more than one filter, their
263 names have to be separated by semicolons. It's also possible to use one
264 <directive>AddOutputFilterByType</directive> directive for each of
267 <p>The configuration below causes all script output labeled as
268 <code>text/html</code> to be processed at first by the
269 <code>INCLUDES</code> filter and then by the <code>DEFLATE</code>
273 <Location /cgi-bin/><br />
275 Options Includes<br />
276 AddOutputFilterByType INCLUDES;DEFLATE text/html<br />
281 <note type="warning"><title>Note</title>
282 <p>Enabling filters with <directive>AddOutputFilterByType</directive>
283 may fail partially or completely in some cases. For example, no
284 filters are applied if the <glossary>MIME-type</glossary> could not be determined and falls
285 back to the <directive module="core">DefaultType</directive> setting,
286 even if the <directive module="core">DefaultType</directive> is the
289 <p>However, if you want to make sure, that the filters will be
290 applied, assign the content type to a resource explicitly, for
291 example with <directive module="mod_mime">AddType</directive> or
292 <directive module="core">ForceType</directive>. Setting the
293 content type within a (non-nph) CGI script is also safe.</p>
295 <p>The by-type output filters are never applied on proxy requests.</p>
299 <seealso><directive module="mod_mime">AddOutputFilter</directive></seealso>
300 <seealso><directive module="core">SetOutputFilter</directive></seealso>
301 <seealso><a href="../filter.html">filters</a></seealso>
305 <name>AllowEncodedSlashes</name>
306 <description>Determines whether encoded path separators in URLs are allowed to
307 be passed through</description>
308 <syntax>AllowEncodedSlashes On|Off</syntax>
309 <default>AllowEncodedSlashes Off</default>
310 <contextlist><context>server config</context><context>virtual host</context>
312 <compatibility>Available in Apache 2.0.46 and later</compatibility>
315 <p>The <directive>AllowEncodedSlashes</directive> directive allows URLs
316 which contain encoded path separators (<code>%2F</code> for <code>/</code>
317 and additionally <code>%5C</code> for <code>\</code> on according systems)
318 to be used. Normally such URLs are refused with a 404 (Not found) error.</p>
320 <p>Turning <directive>AllowEncodedSlashes</directive> <code>On</code> is
321 mostly useful when used in conjunction with <code>PATH_INFO</code>.</p>
323 <note><title>Note</title>
324 <p>Allowing encoded slashes does <em>not</em> imply <em>decoding</em>.
325 Occurrences of <code>%2F</code> or <code>%5C</code> (<em>only</em> on
326 according systems) will be left as such in the otherwise decoded URL
330 <seealso><directive module="core">AcceptPathInfo</directive></seealso>
334 <name>AllowOverride</name>
335 <description>Types of directives that are allowed in
336 <code>.htaccess</code> files</description>
337 <syntax>AllowOverride All|None|<var>directive-type</var>
338 [<var>directive-type</var>] ...</syntax>
339 <default>AllowOverride All</default>
340 <contextlist><context>directory</context></contextlist>
343 <p>When the server finds an <code>.htaccess</code> file (as
344 specified by <directive module="core">AccessFileName</directive>)
345 it needs to know which directives declared in that file can override
346 earlier configuration directives.</p>
348 <note><title>Only available in <Directory> sections</title>
349 <directive>AllowOverride</directive> is valid only in
350 <directive type="section" module="core">Directory</directive>
351 sections specified without regular expressions, not in <directive
352 type="section" module="core">Location</directive>, <directive
353 module="core" type="section">DirectoryMatch</directive> or
354 <directive type="section" module="core">Files</directive> sections.
357 <p>When this directive is set to <code>None</code>, then
358 <a href="#accessfilename">.htaccess</a> files are completely ignored.
359 In this case, the server will not even attempt to read
360 <code>.htaccess</code> files in the filesystem.</p>
362 <p>When this directive is set to <code>All</code>, then any
363 directive which has the .htaccess <a
364 href="directive-dict.html#Context">Context</a> is allowed in
365 <code>.htaccess</code> files.</p>
367 <p>The <var>directive-type</var> can be one of the following
368 groupings of directives.</p>
375 Allow use of the authorization directives (<directive
376 module="mod_authn_dbm">AuthDBMGroupFile</directive>,
377 <directive module="mod_authn_dbm">AuthDBMUserFile</directive>,
378 <directive module="mod_authz_groupfile">AuthGroupFile</directive>,
379 <directive module="core">AuthName</directive>,
380 <directive module="core">AuthType</directive>, <directive
381 module="mod_authn_file">AuthUserFile</directive>, <directive
382 module="core">Require</directive>, <em>etc.</em>).</dd>
387 Allow use of the directives controlling document types (<directive
388 module="core">DefaultType</directive>, <directive
389 module="core">ErrorDocument</directive>, <directive
390 module="core">ForceType</directive>, <directive
391 module="mod_negotiation">LanguagePriority</directive>,
392 <directive module="core">SetHandler</directive>, <directive
393 module="core">SetInputFilter</directive>, <directive
394 module="core">SetOutputFilter</directive>, and
395 <module>mod_mime</module> Add* and Remove*
396 directives, <em>etc.</em>).</dd>
401 Allow use of the directives controlling directory indexing
403 module="mod_autoindex">AddDescription</directive>,
404 <directive module="mod_autoindex">AddIcon</directive>, <directive
405 module="mod_autoindex">AddIconByEncoding</directive>,
406 <directive module="mod_autoindex">AddIconByType</directive>,
407 <directive module="mod_autoindex">DefaultIcon</directive>, <directive
408 module="mod_dir">DirectoryIndex</directive>, <directive
409 module="mod_autoindex">FancyIndexing</directive>, <directive
410 module="mod_autoindex">HeaderName</directive>, <directive
411 module="mod_autoindex">IndexIgnore</directive>, <directive
412 module="mod_autoindex">IndexOptions</directive>, <directive
413 module="mod_autoindex">ReadmeName</directive>,
419 Allow use of the directives controlling host access (<directive
420 module="mod_authz_host">Allow</directive>, <directive
421 module="mod_authz_host">Deny</directive> and <directive
422 module="mod_authz_host">Order</directive>).</dd>
424 <dt>Options[=<var>Option</var>,...]</dt>
427 Allow use of the directives controlling specific directory
428 features (<directive module="core">Options</directive> and
429 <directive module="mod_include">XBitHack</directive>).
430 An equal sign may be given followed by a comma (but no spaces)
431 separated lists of options that may be set using the <directive
432 module="core">Options</directive> command.</dd>
438 AllowOverride AuthConfig Indexes
441 <p>In the example above all directives that are neither in the group
442 <code>AuthConfig</code> nor <code>Indexes</code> cause an internal
446 <seealso><directive module="core">AccessFileName</directive></seealso>
447 <seealso><a href="../configuring.html">Configuration Files</a></seealso>
448 <seealso><a href="../howto/htaccess.html">.htaccess Files</a></seealso>
452 <name>AuthName</name>
453 <description>Authorization realm for use in HTTP
454 authentication</description>
455 <syntax>AuthName <var>auth-domain</var></syntax>
456 <contextlist><context>directory</context><context>.htaccess</context>
458 <override>AuthConfig</override>
461 <p>This directive sets the name of the authorization realm for a
462 directory. This realm is given to the client so that the user
463 knows which username and password to send.
464 <directive>AuthName</directive> takes a single argument; if the
465 realm name contains spaces, it must be enclosed in quotation
466 marks. It must be accompanied by <directive
467 module="core">AuthType</directive> and <directive
468 module="core">Require</directive> directives, and directives such
469 as <directive module="mod_authn_file">AuthUserFile</directive> and
470 <directive module="mod_authz_groupfile">AuthGroupFile</directive> to
476 AuthName "Top Secret"
479 <p>The string provided for the <code>AuthName</code> is what will
480 appear in the password dialog provided by most browsers.</p>
483 href="../howto/auth.html">Authentication, Authorization, and
484 Access Control</a></seealso>
488 <name>AuthType</name>
489 <description>Type of user authentication</description>
490 <syntax>AuthType Basic|Digest</syntax>
491 <contextlist><context>directory</context><context>.htaccess</context>
493 <override>AuthConfig</override>
496 <p>This directive selects the type of user authentication for a
497 directory. Only <code>Basic</code> and <code>Digest</code> are
498 currently implemented.
500 It must be accompanied by <directive
501 module="core">AuthName</directive> and <directive
502 module="core">Require</directive> directives, and directives such
503 as <directive module="mod_authn_file">AuthUserFile</directive> and
504 <directive module="mod_authz_groupfile">AuthGroupFile</directive> to
507 <seealso><a href="../howto/auth.html">Authentication, Authorization,
508 and Access Control</a></seealso>
512 <name>CGIMapExtension</name>
513 <description>Technique for locating the interpreter for CGI
514 scripts</description>
515 <syntax>CGIMapExtension <var>cgi-path</var> <var>.extension</var></syntax>
516 <contextlist><context>directory</context><context>.htaccess</context>
518 <override>FileInfo</override>
519 <compatibility>NetWare only</compatibility>
522 <p>This directive is used to control how Apache finds the
523 interpreter used to run CGI scripts. For example, setting
524 <code>CGIMapExtension sys:\foo.nlm .foo</code> will
525 cause all CGI script files with a <code>.foo</code> extension to
526 be passed to the FOO interpreter.</p>
531 <name>ContentDigest</name>
532 <description>Enables the generation of <code>Content-MD5</code> HTTP Response
533 headers</description>
534 <syntax>ContentDigest On|Off</syntax>
535 <default>ContentDigest Off</default>
536 <contextlist><context>server config</context><context>virtual host</context>
537 <context>directory</context><context>.htaccess</context>
539 <override>Options</override>
540 <status>Experimental</status>
543 <p>This directive enables the generation of
544 <code>Content-MD5</code> headers as defined in RFC1864
545 respectively RFC2068.</p>
547 <p>MD5 is an algorithm for computing a "message digest"
548 (sometimes called "fingerprint") of arbitrary-length data, with
549 a high degree of confidence that any alterations in the data
550 will be reflected in alterations in the message digest.</p>
552 <p>The <code>Content-MD5</code> header provides an end-to-end
553 message integrity check (MIC) of the entity-body. A proxy or
554 client may check this header for detecting accidental
555 modification of the entity-body in transit. Example header:</p>
558 Content-MD5: AuLb7Dp1rqtRtxz2m9kRpA==
561 <p>Note that this can cause performance problems on your server
562 since the message digest is computed on every request (the
563 values are not cached).</p>
565 <p><code>Content-MD5</code> is only sent for documents served
566 by the <module>core</module>, and not by any module. For example,
567 SSI documents, output from CGI scripts, and byte range responses
568 do not have this header.</p>
573 <name>DefaultType</name>
574 <description>MIME content-type that will be sent if the
575 server cannot determine a type in any other way</description>
576 <syntax>DefaultType <var>MIME-type</var></syntax>
577 <default>DefaultType text/plain</default>
578 <contextlist><context>server config</context><context>virtual host</context>
579 <context>directory</context><context>.htaccess</context>
581 <override>FileInfo</override>
584 <p>There will be times when the server is asked to provide a
585 document whose type cannot be determined by its <glossary
586 ref="mime-type">MIME types</glossary> mappings.</p>
588 <p>The server must inform the client of the content-type of the
589 document, so in the event of an unknown type it uses the
590 <code>DefaultType</code>. For example:</p>
593 DefaultType image/gif
596 <p>would be appropriate for a directory which contained many GIF
597 images with filenames missing the <code>.gif</code> extension.</p>
599 <p>Note that unlike <directive
600 module="core">ForceType</directive>, this directive only
601 provides the default mime-type. All other mime-type definitions,
602 including filename extensions, that might identify the media type
603 will override this default.</p>
607 <directivesynopsis type="section">
608 <name>Directory</name>
609 <description>Enclose a group of directives that apply only to the
610 named file-system directory and sub-directories</description>
611 <syntax><Directory <var>directory-path</var>>
612 ... </Directory></syntax>
613 <contextlist><context>server config</context><context>virtual host</context>
617 <p><directive type="section">Directory</directive> and
618 <code></Directory></code> are used to enclose a group of
619 directives that will apply only to the named directory and
620 sub-directories of that directory. Any directive that is allowed
621 in a directory context may be used. <var>Directory-path</var> is
622 either the full path to a directory, or a wild-card string using
623 Unix shell-style matching. In a wild-card string, <code>?</code> matches
624 any single character, and <code>*</code> matches any sequences of
625 characters. You may also use <code>[]</code> character ranges. None
626 of the wildcards match a `/' character, so <code><Directory
627 /*/public_html></code> will not match
628 <code>/home/user/public_html</code>, but <code><Directory
629 /home/*/public_html></code> will match. Example:</p>
632 <Directory /usr/local/httpd/htdocs><br />
634 Options Indexes FollowSymLinks<br />
640 <p>Be careful with the <var>directory-path</var> arguments:
641 They have to literally match the filesystem path which Apache uses
642 to access the files. Directives applied to a particular
643 <code><Directory></code> will not apply to files accessed from
644 that same directory via a different path, such as via different symbolic
648 <p><glossary ref="regex">Regular
649 expressions</glossary> can also be used, with the addition of the
650 <code>~</code> character. For example:</p>
653 <Directory ~ "^/www/.*/[0-9]{3}">
656 <p>would match directories in <code>/www/</code> that consisted of
659 <p>If multiple (non-regular expression) <directive
660 type="section">Directory</directive> sections
661 match the directory (or one of its parents) containing a document,
662 then the directives are applied in the order of shortest match
663 first, interspersed with the directives from the <a
664 href="#accessfilename">.htaccess</a> files. For example,
668 <Directory /><br />
670 AllowOverride None<br />
672 </Directory><br />
674 <Directory /home/><br />
676 AllowOverride FileInfo<br />
681 <p>for access to the document <code>/home/web/dir/doc.html</code>
685 <li>Apply directive <code>AllowOverride None</code>
686 (disabling <code>.htaccess</code> files).</li>
688 <li>Apply directive <code>AllowOverride FileInfo</code> (for
689 directory <code>/home</code>).</li>
691 <li>Apply any <code>FileInfo</code> directives in
692 <code>/home/.htaccess</code>, <code>/home/web/.htaccess</code> and
693 <code>/home/web/dir/.htaccess</code> in that order.</li>
696 <p>Regular expressions are not considered until after all of the
697 normal sections have been applied. Then all of the regular
698 expressions are tested in the order they appeared in the
699 configuration file. For example, with</p>
702 <Directory ~ abc$><br />
704 # ... directives here ...<br />
709 <p>the regular expression section won't be considered until after
710 all normal <directive type="section">Directory</directive>s and
711 <code>.htaccess</code> files have been applied. Then the regular
712 expression will match on <code>/home/abc/public_html/abc</code> and
713 the corresponding <directive type="section">Directory</directive> will
716 <p><strong>Note that the default Apache access for
717 <code><Directory /></code> is <code>Allow from All</code>.
718 This means that Apache will serve any file mapped from an URL. It is
719 recommended that you change this with a block such
723 <Directory /><br />
725 Order Deny,Allow<br />
731 <p><strong>and then override this for directories you
732 <em>want</em> accessible. See the <a
733 href="../misc/security_tips.html">Security Tips</a> page for more
734 details.</strong></p>
736 <p>The directory sections occur in the <code>httpd.conf</code> file.
737 <directive type="section">Directory</directive> directives
738 cannot nest, and cannot appear in a <directive module="core"
739 type="section">Limit</directive> or <directive module="core"
740 type="section">LimitExcept</directive> section.</p>
742 <seealso><a href="../sections.html">How <Directory>,
743 <Location> and <Files> sections work</a> for an
744 explanation of how these different sections are combined when a
745 request is received</seealso>
748 <directivesynopsis type="section">
749 <name>DirectoryMatch</name>
750 <description>Enclose directives that apply to
751 file-system directories matching a regular expression and their
752 subdirectories</description>
753 <syntax><DirectoryMatch <var>regex</var>>
754 ... </DirectoryMatch></syntax>
755 <contextlist><context>server config</context><context>virtual host</context>
759 <p><directive type="section">DirectoryMatch</directive> and
760 <code></DirectoryMatch></code> are used to enclose a group
761 of directives which will apply only to the named directory and
762 sub-directories of that directory, the same as <directive
763 module="core" type="section">Directory</directive>. However, it
764 takes as an argument a <glossary ref="regex">regular
765 expression</glossary>. For example:</p>
768 <DirectoryMatch "^/www/(.+/)?[0-9]{3}">
771 <p>would match directories in <code>/www/</code> that consisted of three
774 <seealso><directive type="section" module="core">Directory</directive> for
775 a description of how regular expressions are mixed in with normal
776 <directive type="section">Directory</directive>s</seealso>
778 href="../sections.html">How <Directory>, <Location> and
779 <Files> sections work</a> for an explanation of how these different
780 sections are combined when a request is received</seealso>
784 <name>DocumentRoot</name>
785 <description>Directory that forms the main document tree visible
786 from the web</description>
787 <syntax>DocumentRoot <var>directory-path</var></syntax>
788 <default>DocumentRoot /usr/local/apache/htdocs</default>
789 <contextlist><context>server config</context><context>virtual host</context>
793 <p>This directive sets the directory from which <program>httpd</program>
794 will serve files. Unless matched by a directive like <directive
795 module="mod_alias">Alias</directive>, the server appends the
796 path from the requested URL to the document root to make the
797 path to the document. Example:</p>
800 DocumentRoot /usr/web
804 <code>http://www.my.host.com/index.html</code> refers to
805 <code>/usr/web/index.html</code>. If the <var>directory-path</var> is
806 not absolute then it is assumed to be relative to the <directive
807 module="core">ServerRoot</directive>.</p>
809 <p>The <directive>DocumentRoot</directive> should be specified without
810 a trailing slash.</p>
812 <seealso><a href="../urlmapping.html">Mapping URLs to Filesystem
813 Location</a></seealso>
817 <name>EnableMMAP</name>
818 <description>Use memory-mapping to read files during delivery</description>
819 <syntax>EnableMMAP On|Off</syntax>
820 <default>EnableMMAP On</default>
821 <contextlist><context>server config</context><context>virtual host</context>
822 <context>directory</context><context>.htaccess</context>
824 <override>FileInfo</override>
827 <p>This directive controls whether the <program>httpd</program> may use
828 memory-mapping if it needs to read the contents of a file during
829 delivery. By default, when the handling of a request requires
830 access to the data within a file -- for example, when delivering a
831 server-parsed file using <module>mod_include</module> -- Apache
832 memory-maps the file if the OS supports it.</p>
834 <p>This memory-mapping sometimes yields a performance improvement.
835 But in some environments, it is better to disable the memory-mapping
836 to prevent operational problems:</p>
839 <li>On some multiprocessor systems, memory-mapping can reduce the
840 performance of the <program>httpd</program>.</li>
841 <li>With an NFS-mounted <directive module="core">DocumentRoot</directive>,
842 the <program>httpd</program> may crash due to a segmentation fault if a file
843 is deleted or truncated while the <program>httpd</program> has it
847 <p>For server configurations that are vulnerable to these problems,
848 you should disable memory-mapping of delivered files by specifying:</p>
854 <p>For NFS mounted files, this feature may be disabled explicitly for
855 the offending files by specifying:</p>
858 <Directory "/path-to-nfs-files">
868 <name>EnableSendfile</name>
869 <description>Use the kernel sendfile support to deliver files to the client</description>
870 <syntax>EnableSendfile On|Off</syntax>
871 <default>EnableSendfile On</default>
872 <contextlist><context>server config</context><context>virtual host</context>
873 <context>directory</context><context>.htaccess</context>
875 <override>FileInfo</override>
876 <compatibility>Available in version 2.0.44 and later</compatibility>
879 <p>This directive controls whether <program>httpd</program> may use the
880 sendfile support from the kernel to transmit file contents to the client.
881 By default, when the handling of a request requires no access
882 to the data within a file -- for example, when delivering a
883 static file -- Apache uses sendfile to deliver the file contents
884 without ever reading the file if the OS supports it.</p>
886 <p>This sendfile mechanism avoids separate read and send operations,
887 and buffer allocations. But on some platforms or within some
888 filesystems, it is better to disable this feature to avoid
889 operational problems:</p>
892 <li>Some platforms may have broken sendfile support that the build
893 system did not detect, especially if the binaries were built on
894 another box and moved to such a machine with broken sendfile
896 <li>On Linux the use of sendfile triggers TCP-checksum
897 offloading bugs on certain networking cards when using IPv6.</li>
898 <li>With a network-mounted <directive
899 module="core">DocumentRoot</directive> (e.g., NFS or SMB),
900 the kernel may be unable to serve the network file through
904 <p>For server configurations that are vulnerable to these problems,
905 you should disable this feature by specifying:</p>
911 <p>For NFS or SMB mounted files, this feature may be disabled explicitly
912 for the offending files by specifying:</p>
915 <Directory "/path-to-nfs-files">
925 <name>ErrorDocument</name>
926 <description>What the server will return to the client
927 in case of an error</description>
928 <syntax>ErrorDocument <var>error-code</var> <var>document</var></syntax>
929 <contextlist><context>server config</context><context>virtual host</context>
930 <context>directory</context><context>.htaccess</context>
932 <override>FileInfo</override>
933 <compatibility>Quoting syntax for text messages is different in Apache
937 <p>In the event of a problem or error, Apache can be configured
938 to do one of four things,</p>
941 <li>output a simple hardcoded error message</li>
943 <li>output a customized message</li>
945 <li>redirect to a local <var>URL-path</var> to handle the
948 <li>redirect to an external <var>URL</var> to handle the
952 <p>The first option is the default, while options 2-4 are
953 configured using the <directive>ErrorDocument</directive>
954 directive, which is followed by the HTTP response code and a URL
955 or a message. Apache will sometimes offer additional information
956 regarding the problem/error.</p>
958 <p>URLs can begin with a slash (/) for local web-paths (relative
959 to the <directive module="core">DocumentRoot</directive>), or be a
960 full URL which the client can resolve. Alternatively, a message
961 can be provided to be displayed by the browser. Examples:</p>
964 ErrorDocument 500 http://foo.example.com/cgi-bin/tester<br />
965 ErrorDocument 404 /cgi-bin/bad_urls.pl<br />
966 ErrorDocument 401 /subscription_info.html<br />
967 ErrorDocument 403 "Sorry can't allow you access today"
970 <p>Additionally, the special value <code>default</code> can be used
971 to specify Apache's simple hardcoded message. While not required
972 under normal circumstances, <code>default</code> will restore
973 Apache's simple hardcoded message for configurations that would
974 otherwise inherit an existing <directive>ErrorDocument</directive>.</p>
977 ErrorDocument 404 /cgi-bin/bad_urls.pl<br /><br />
978 <Directory /web/docs><br />
980 ErrorDocument 404 default<br />
985 <p>Note that when you specify an <directive>ErrorDocument</directive>
986 that points to a remote URL (ie. anything with a method such as
987 <code>http</code> in front of it), Apache will send a redirect to the
988 client to tell it where to find the document, even if the
989 document ends up being on the same server. This has several
990 implications, the most important being that the client will not
991 receive the original error status code, but instead will
992 receive a redirect status code. This in turn can confuse web
993 robots and other clients which try to determine if a URL is
994 valid using the status code. In addition, if you use a remote
995 URL in an <code>ErrorDocument 401</code>, the client will not
996 know to prompt the user for a password since it will not
997 receive the 401 status code. Therefore, <strong>if you use an
998 <code>ErrorDocument 401</code> directive then it must refer to a local
999 document.</strong></p>
1001 <p>Microsoft Internet Explorer (MSIE) will by default ignore
1002 server-generated error messages when they are "too small" and substitute
1003 its own "friendly" error messages. The size threshold varies depending on
1004 the type of error, but in general, if you make your error document
1005 greater than 512 bytes, then MSIE will show the server-generated
1006 error rather than masking it. More information is available in
1007 Microsoft Knowledge Base article <a
1008 href="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q294807"
1011 <p>Although most error messages can be overriden, there are certain
1012 circumstances where the internal messages are used regardless of the
1013 setting of <directive module="core">ErrorDocument</directive>. In
1014 particular, if a malformed request is detected, normal request processing
1015 will be immediately halted and the internal error message returned.
1016 This is necessary to guard against security problems caused by
1019 <p>Prior to version 2.0, messages were indicated by prefixing
1020 them with a single unmatched double quote character.</p>
1023 <seealso><a href="../custom-error.html">documentation of
1024 customizable responses</a></seealso>
1025 </directivesynopsis>
1028 <name>ErrorLog</name>
1029 <description>Location where the server will log errors</description>
1030 <syntax> ErrorLog <var>file-path</var>|syslog[:<var>facility</var>]</syntax>
1031 <default>ErrorLog logs/error_log (Unix) ErrorLog logs/error.log (Windows and OS/2)</default>
1032 <contextlist><context>server config</context><context>virtual host</context>
1036 <p>The <directive>ErrorLog</directive> directive sets the name of
1037 the file to which the server will log any errors it encounters. If
1038 the <var>file-path</var> is not absolute then it is assumed to be
1039 relative to the <directive module="core">ServerRoot</directive>.</p>
1041 <example><title>Example</title>
1042 ErrorLog /var/log/httpd/error_log
1045 <p>If the <var>file-path</var>
1046 begins with a pipe (|) then it is assumed to be a command to spawn
1047 to handle the error log.</p>
1049 <example><title>Example</title>
1050 ErrorLog "|/usr/local/bin/httpd_errors"
1053 <p>Using <code>syslog</code> instead of a filename enables logging
1054 via syslogd(8) if the system supports it. The default is to use
1055 syslog facility <code>local7</code>, but you can override this by
1056 using the <code>syslog:<var>facility</var></code> syntax where
1057 <var>facility</var> can be one of the names usually documented in
1060 <example><title>Example</title>
1061 ErrorLog syslog:user
1064 <p>SECURITY: See the <a
1065 href="../misc/security_tips.html#serverroot">security tips</a>
1066 document for details on why your security could be compromised
1067 if the directory where log files are stored is writable by
1068 anyone other than the user that starts the server.</p>
1069 <note type="warning"><title>Note</title>
1070 <p>When entering a file path on non-Unix platforms, care should be taken
1071 to make sure that only forward slashed are used even though the platform
1072 may allow the use of back slashes. In general it is a good idea to always
1073 use forward slashes throughout the configuration files.</p>
1076 <seealso><directive module="core">LogLevel</directive></seealso>
1077 <seealso><a href="../logs.html">Apache Log Files</a></seealso>
1078 </directivesynopsis>
1081 <name>FileETag</name>
1082 <description>File attributes used to create the ETag
1083 HTTP response header</description>
1084 <syntax>FileETag <var>component</var> ...</syntax>
1085 <default>FileETag INode MTime Size</default>
1086 <contextlist><context>server config</context><context>virtual host</context>
1087 <context>directory</context><context>.htaccess</context>
1089 <override>FileInfo</override>
1093 The <directive>FileETag</directive> directive configures the file
1094 attributes that are used to create the <code>ETag</code> (entity
1095 tag) response header field when the document is based on a file.
1096 (The <code>ETag</code> value is used in cache management to save
1097 network bandwidth.) In Apache 1.3.22 and earlier, the
1098 <code>ETag</code> value was <em>always</em> formed
1099 from the file's inode, size, and last-modified time (mtime). The
1100 <directive>FileETag</directive> directive allows you to choose
1101 which of these -- if any -- should be used. The recognized keywords are:
1105 <dt><strong>INode</strong></dt>
1106 <dd>The file's i-node number will be included in the calculation</dd>
1107 <dt><strong>MTime</strong></dt>
1108 <dd>The date and time the file was last modified will be included</dd>
1109 <dt><strong>Size</strong></dt>
1110 <dd>The number of bytes in the file will be included</dd>
1111 <dt><strong>All</strong></dt>
1112 <dd>All available fields will be used. This is equivalent to:
1113 <example>FileETag INode MTime Size</example></dd>
1114 <dt><strong>None</strong></dt>
1115 <dd>If a document is file-based, no <code>ETag</code> field will be
1116 included in the response</dd>
1119 <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
1120 keywords may be prefixed with either <code>+</code> or <code>-</code>,
1121 which allow changes to be made to the default setting inherited
1122 from a broader scope. Any keyword appearing without such a prefix
1123 immediately and completely cancels the inherited setting.</p>
1125 <p>If a directory's configuration includes
1126 <code>FileETag INode MTime Size</code>, and a
1127 subdirectory's includes <code>FileETag -INode</code>,
1128 the setting for that subdirectory (which will be inherited by
1129 any sub-subdirectories that don't override it) will be equivalent to
1130 <code>FileETag MTime Size</code>.</p>
1132 </directivesynopsis>
1134 <directivesynopsis type="section">
1136 <description>Contains directives that apply to matched
1137 filenames</description>
1138 <syntax><Files <var>filename</var>> ... </Files></syntax>
1139 <contextlist><context>server config</context><context>virtual host</context>
1140 <context>directory</context><context>.htaccess</context>
1142 <override>All</override>
1145 <p>The <directive type="section">Files</directive> directive
1146 limits the scope of the enclosed directives by filename. It is comparable
1147 to the <directive module="core" type="section">Directory</directive>
1148 and <directive module="core" type="section">Location</directive>
1149 directives. It should be matched with a <code></Files></code>
1150 directive. The directives given within this section will be applied to
1151 any object with a basename (last component of filename) matching the
1152 specified filename. <directive type="section">Files</directive>
1153 sections are processed in the order they appear in the
1154 configuration file, after the <directive module="core"
1155 type="section">Directory</directive> sections and
1156 <code>.htaccess</code> files are read, but before <directive
1157 type="section" module="core">Location</directive> sections. Note
1158 that <directive type="section">Files</directive> can be nested
1159 inside <directive type="section"
1160 module="core">Directory</directive> sections to restrict the
1161 portion of the filesystem they apply to.</p>
1163 <p>The <var>filename</var> argument should include a filename, or
1164 a wild-card string, where <code>?</code> matches any single character,
1165 and <code>*</code> matches any sequences of characters.
1166 <glossary ref="regex">Regular expressions</glossary>
1167 can also be used, with the addition of the
1168 <code>~</code> character. For example:</p>
1171 <Files ~ "\.(gif|jpe?g|png)$">
1174 <p>would match most common Internet graphics formats. <directive
1175 module="core" type="section">FilesMatch</directive> is preferred,
1178 <p>Note that unlike <directive type="section"
1179 module="core">Directory</directive> and <directive type="section"
1180 module="core">Location</directive> sections, <directive
1181 type="section">Files</directive> sections can be used inside
1182 <code>.htaccess</code> files. This allows users to control access to
1183 their own files, at a file-by-file level.</p>
1186 <seealso><a href="../sections.html">How <Directory>, <Location>
1187 and <Files> sections work</a> for an explanation of how these
1188 different sections are combined when a request is received</seealso>
1189 </directivesynopsis>
1191 <directivesynopsis type="section">
1192 <name>FilesMatch</name>
1193 <description>Contains directives that apply to regular-expression matched
1194 filenames</description>
1195 <syntax><FilesMatch <var>regex</var>> ... </FilesMatch></syntax>
1196 <contextlist><context>server config</context><context>virtual host</context>
1197 <context>directory</context><context>.htaccess</context>
1199 <override>All</override>
1202 <p>The <directive type="section">FilesMatch</directive> directive
1203 limits the scope of the enclosed directives by filename, just as the
1204 <directive module="core" type="section">Files</directive> directive
1205 does. However, it accepts a <glossary ref="regex">regular
1206 expression</glossary>. For example:</p>
1209 <FilesMatch "\.(gif|jpe?g|png)$">
1212 <p>would match most common Internet graphics formats.</p>
1215 <seealso><a href="../sections.html">How <Directory>, <Location>
1216 and <Files> sections work</a> for an explanation of how these
1217 different sections are combined when a request is received</seealso>
1218 </directivesynopsis>
1221 <name>ForceType</name>
1222 <description>Forces all matching files to be served with the specified
1223 MIME content-type</description>
1224 <syntax>ForceType <var>MIME-type</var>|None</syntax>
1225 <contextlist><context>directory</context><context>.htaccess</context>
1227 <override>FileInfo</override>
1228 <compatibility>Moved to the core in Apache 2.0</compatibility>
1231 <p>When placed into an <code>.htaccess</code> file or a
1232 <directive type="section" module="core">Directory</directive>, or
1233 <directive type="section" module="core">Location</directive> or
1234 <directive type="section" module="core">Files</directive>
1235 section, this directive forces all matching files to be served
1236 with the content type identification given by
1237 <var>MIME-type</var>. For example, if you had a directory full of
1238 GIF files, but did not want to label them all with <code>.gif</code>,
1239 you might want to use:</p>
1245 <p>Note that unlike <directive module="core">DefaultType</directive>,
1246 this directive overrides all mime-type associations, including
1247 filename extensions, that might identify the media type.</p>
1249 <p>You can override any <directive>ForceType</directive> setting
1250 by using the value of <code>None</code>:</p>
1253 # force all files to be image/gif:<br />
1254 <Location /images><br />
1256 ForceType image/gif<br />
1258 </Location><br />
1260 # but normal mime-type associations here:<br />
1261 <Location /images/mixed><br />
1263 ForceType None<br />
1268 </directivesynopsis>
1271 <name>HostnameLookups</name>
1272 <description>Enables DNS lookups on client IP addresses</description>
1273 <syntax>HostnameLookups On|Off|Double</syntax>
1274 <default>HostnameLookups Off</default>
1275 <contextlist><context>server config</context><context>virtual host</context>
1276 <context>directory</context></contextlist>
1279 <p>This directive enables DNS lookups so that host names can be
1280 logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
1281 The value <code>Double</code> refers to doing double-reverse
1282 DNS lookup. That is, after a reverse lookup is performed, a forward
1283 lookup is then performed on that result. At least one of the IP
1284 addresses in the forward lookup must match the original
1285 address. (In "tcpwrappers" terminology this is called
1286 <code>PARANOID</code>.)</p>
1288 <p>Regardless of the setting, when <module>mod_authz_host</module> is
1289 used for controlling access by hostname, a double reverse lookup
1290 will be performed. This is necessary for security. Note that the
1291 result of this double-reverse isn't generally available unless you
1292 set <code>HostnameLookups Double</code>. For example, if only
1293 <code>HostnameLookups On</code> and a request is made to an object
1294 that is protected by hostname restrictions, regardless of whether
1295 the double-reverse fails or not, CGIs will still be passed the
1296 single-reverse result in <code>REMOTE_HOST</code>.</p>
1298 <p>The default is <code>Off</code> in order to save the network
1299 traffic for those sites that don't truly need the reverse
1300 lookups done. It is also better for the end users because they
1301 don't have to suffer the extra latency that a lookup entails.
1302 Heavily loaded sites should leave this directive
1303 <code>Off</code>, since DNS lookups can take considerable
1304 amounts of time. The utility <program>logresolve</program>, compiled by
1305 default to the <code>bin</code> subdirectory of your installation
1306 directory, can be used to look up host names from logged IP addresses
1309 </directivesynopsis>
1311 <directivesynopsis type="section">
1312 <name>IfDefine</name>
1313 <description>Encloses directives that will be processed only
1314 if a test is true at startup</description>
1315 <syntax><IfDefine [!]<var>parameter-name</var>> ...
1316 </IfDefine></syntax>
1317 <contextlist><context>server config</context><context>virtual host</context>
1318 <context>directory</context><context>.htaccess</context>
1320 <override>All</override>
1323 <p>The <code><IfDefine <var>test</var>>...</IfDefine>
1324 </code> section is used to mark directives that are conditional. The
1325 directives within an <directive type="section">IfDefine</directive>
1326 section are only processed if the <var>test</var> is true. If <var>
1327 test</var> is false, everything between the start and end markers is
1330 <p>The <var>test</var> in the <directive type="section"
1331 >IfDefine</directive> section directive can be one of two forms:</p>
1334 <li><var>parameter-name</var></li>
1336 <li><code>!</code><var>parameter-name</var></li>
1339 <p>In the former case, the directives between the start and end
1340 markers are only processed if the parameter named
1341 <var>parameter-name</var> is defined. The second format reverses
1342 the test, and only processes the directives if
1343 <var>parameter-name</var> is <strong>not</strong> defined.</p>
1345 <p>The <var>parameter-name</var> argument is a define as given on
1346 the <program>httpd</program> command line via <code>-D<var>parameter-</var>
1347 </code>, at the time the server was started.</p>
1349 <p><directive type="section">IfDefine</directive> sections are
1350 nest-able, which can be used to implement simple
1351 multiple-parameter tests. Example:</p>
1354 httpd -DReverseProxy ...<br />
1357 <IfDefine ReverseProxy><br />
1359 LoadModule rewrite_module modules/mod_rewrite.so<br />
1360 LoadModule proxy_module modules/libproxy.so<br />
1365 </directivesynopsis>
1367 <directivesynopsis type="section">
1368 <name>IfModule</name>
1369 <description>Encloses directives that are processed conditional on the
1370 presence or absence of a specific module</description>
1371 <syntax><IfModule [!]<var>module-file</var>|<var>module-identifier</var>> ...
1372 </IfModule></syntax>
1373 <contextlist><context>server config</context><context>virtual host</context>
1374 <context>directory</context><context>.htaccess</context>
1376 <override>All</override>
1377 <compatibility>Module identifiers are available in version 2.1 and
1378 later.</compatibility>
1381 <p>The <code><IfModule <var>test</var>>...</IfModule></code>
1382 section is used to mark directives that are conditional on the presence of
1383 a specific module. The directives within an <directive type="section"
1384 >IfModule</directive> section are only processed if the <var>test</var>
1385 is true. If <var>test</var> is false, everything between the start and
1386 end markers is ignored.</p>
1388 <p>The <var>test</var> in the <directive type="section"
1389 >IfModule</directive> section directive can be one of two forms:</p>
1392 <li><var>module</var></li>
1394 <li>!<var>module</var></li>
1397 <p>In the former case, the directives between the start and end
1398 markers are only processed if the module named <var>module</var>
1399 is included in Apache -- either compiled in or
1400 dynamically loaded using <directive module="mod_so"
1401 >LoadModule</directive>. The second format reverses the test,
1402 and only processes the directives if <var>module</var> is
1403 <strong>not</strong> included.</p>
1405 <p>The <var>module</var> argument can be either the module identifier or
1406 the file name of the module, at the time it was compiled. For example,
1407 <code>rewrite_module</code> is the identifier and
1408 <code>mod_rewrite.c</code> is the file name. If a module consists of
1409 several source files, use the name of the file containing the string
1410 <code>STANDARD20_MODULE_STUFF</code>.</p>
1412 <p><directive type="section">IfModule</directive> sections are
1413 nest-able, which can be used to implement simple multiple-module
1416 <note>This section should only be used if you need to have one
1417 configuration file that works whether or not a specific module
1418 is available. In normal operation, directives need not be
1419 placed in <directive type="section">IfModule</directive>
1422 </directivesynopsis>
1425 <name>Include</name>
1426 <description>Includes other configuration files from within
1427 the server configuration files</description>
1428 <syntax>Include <var>file-path</var>|<var>directory-path</var></syntax>
1429 <contextlist><context>server config</context><context>virtual host</context>
1430 <context>directory</context>
1432 <compatibility>Wildcard matching available in 2.0.41 and later</compatibility>
1435 <p>This directive allows inclusion of other configuration files
1436 from within the server configuration files.</p>
1438 <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used to
1439 include several files at once, in alphabetical order. In
1440 addition, if <directive>Include</directive> points to a directory,
1441 rather than a file, Apache will read all files in that directory
1442 and any subdirectory. But including entire directories is not
1443 recommended, because it is easy to accidentally leave temporary
1444 files in a directory that can cause <program>httpd</program> to
1447 <p>The file path specified may be an absolute path, or may be relative
1448 to the <directive module="core">ServerRoot</directive> directory.</p>
1453 Include /usr/local/apache2/conf/ssl.conf<br />
1454 Include /usr/local/apache2/conf/vhosts/*.conf
1457 <p>Or, providing paths relative to your <directive
1458 module="core">ServerRoot</directive> directory:</p>
1461 Include conf/ssl.conf<br />
1462 Include conf/vhosts/*.conf
1465 <p>Running <code>apachectl configtest</code> will give you a list
1466 of the files that are being processed during the configuration
1470 root@host# apachectl configtest<br />
1471 Processing config file: /usr/local/apache2/conf/ssl.conf<br />
1472 Processing config file: /usr/local/apache2/conf/vhosts/vhost1.conf<br />
1473 Processing config file: /usr/local/apache2/conf/vhosts/vhost2.conf<br />
1478 <seealso><program>apachectl</program></seealso>
1479 </directivesynopsis>
1482 <name>KeepAlive</name>
1483 <description>Enables HTTP persistent connections</description>
1484 <syntax>KeepAlive On|Off</syntax>
1485 <default>KeepAlive On</default>
1486 <contextlist><context>server config</context><context>virtual host</context>
1490 <p>The Keep-Alive extension to HTTP/1.0 and the persistent
1491 connection feature of HTTP/1.1 provide long-lived HTTP sessions
1492 which allow multiple requests to be sent over the same TCP
1493 connection. In some cases this has been shown to result in an
1494 almost 50% speedup in latency times for HTML documents with
1495 many images. To enable Keep-Alive connections, set
1496 <code>KeepAlive On</code>.</p>
1498 <p>For HTTP/1.0 clients, Keep-Alive connections will only be
1499 used if they are specifically requested by a client. In
1500 addition, a Keep-Alive connection with an HTTP/1.0 client can
1501 only be used when the length of the content is known in
1502 advance. This implies that dynamic content such as CGI output,
1503 SSI pages, and server-generated directory listings will
1504 generally not use Keep-Alive connections to HTTP/1.0 clients.
1505 For HTTP/1.1 clients, persistent connections are the default
1506 unless otherwise specified. If the client requests it, chunked
1507 encoding will be used in order to send content of unknown
1508 length over persistent connections.</p>
1511 <seealso><directive module="core">MaxKeepAliveRequests</directive></seealso>
1512 </directivesynopsis>
1515 <name>KeepAliveTimeout</name>
1516 <description>Amount of time the server will wait for subsequent
1517 requests on a persistent connection</description>
1518 <syntax>KeepAliveTimeout <var>seconds</var></syntax>
1519 <default>KeepAliveTimeout 5</default>
1520 <contextlist><context>server config</context><context>virtual host</context>
1524 <p>The number of seconds Apache will wait for a subsequent
1525 request before closing the connection. Once a request has been
1526 received, the timeout value specified by the
1527 <directive module="core">Timeout</directive> directive applies.</p>
1529 <p>Setting <directive>KeepAliveTimeout</directive> to a high value
1530 may cause performance problems in heavily loaded servers. The
1531 higher the timeout, the more server processes will be kept
1532 occupied waiting on connections with idle clients.</p>
1534 </directivesynopsis>
1536 <directivesynopsis type="section">
1538 <description>Restrict enclosed access controls to only certain HTTP
1539 methods</description>
1540 <syntax><Limit <var>method</var> [<var>method</var>] ... > ...
1541 </Limit></syntax>
1542 <contextlist><context>server config</context><context>virtual host</context>
1543 <context>directory</context><context>.htaccess</context>
1545 <override>All</override>
1548 <p>Access controls are normally effective for
1549 <strong>all</strong> access methods, and this is the usual
1550 desired behavior. <strong>In the general case, access control
1551 directives should not be placed within a
1552 <directive type="section">Limit</directive> section.</strong></p>
1554 <p>The purpose of the <directive type="section">Limit</directive>
1555 directive is to restrict the effect of the access controls to the
1556 nominated HTTP methods. For all other methods, the access
1557 restrictions that are enclosed in the <directive
1558 type="section">Limit</directive> bracket <strong>will have no
1559 effect</strong>. The following example applies the access control
1560 only to the methods <code>POST</code>, <code>PUT</code>, and
1561 <code>DELETE</code>, leaving all other methods unprotected:</p>
1564 <Limit POST PUT DELETE><br />
1566 Require valid-user<br />
1571 <p>The method names listed can be one or more of: <code>GET</code>,
1572 <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
1573 <code>CONNECT</code>, <code>OPTIONS</code>,
1574 <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
1575 <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
1576 <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
1577 case-sensitive.</strong> If <code>GET</code> is used it will also
1578 restrict <code>HEAD</code> requests. The <code>TRACE</code> method
1579 cannot be limited.</p>
1581 <note type="warning">A <directive type="section"
1582 module="core">LimitExcept</directive> section should always be
1583 used in preference to a <directive type="section"
1584 module="core">Limit</directive> section when restricting access,
1585 since a <directive type="section"
1586 module="core">LimitExcept</directive> section provides protection
1587 against arbitrary methods.</note>
1590 </directivesynopsis>
1592 <directivesynopsis type="section">
1593 <name>LimitExcept</name>
1594 <description>Restrict access controls to all HTTP methods
1595 except the named ones</description>
1596 <syntax><LimitExcept <var>method</var> [<var>method</var>] ... > ...
1597 </LimitExcept></syntax>
1598 <contextlist><context>server config</context><context>virtual host</context>
1599 <context>directory</context><context>.htaccess</context>
1601 <override>All</override>
1604 <p><directive type="section">LimitExcept</directive> and
1605 <code></LimitExcept></code> are used to enclose
1606 a group of access control directives which will then apply to any
1607 HTTP access method <strong>not</strong> listed in the arguments;
1608 i.e., it is the opposite of a <directive type="section"
1609 module="core">Limit</directive> section and can be used to control
1610 both standard and nonstandard/unrecognized methods. See the
1611 documentation for <directive module="core"
1612 type="section">Limit</directive> for more details.</p>
1617 <LimitExcept POST GET><br />
1619 Require valid-user<br />
1621 </LimitExcept>
1625 </directivesynopsis>
1628 <name>LimitInternalRecursion</name>
1629 <description>Determine maximum number of internal redirects and nested
1630 subrequests</description>
1631 <syntax>LimitInternalRecursion <var>number</var> [<var>number</var>]</syntax>
1632 <default>LimitInternalRecursion 10</default>
1633 <contextlist><context>server config</context><context>virtual host</context>
1635 <compatibility>Available in Apache 2.0.47 and later</compatibility>
1638 <p>An internal redirect happens, for example, when using the <directive
1639 module="mod_actions">Action</directive> directive, which internally
1640 redirects the original request to a CGI script. A subrequest is Apache's
1641 mechanism to find out what would happen for some URI if it were requested.
1642 For example, <module>mod_dir</module> uses subrequests to look for the
1643 files listed in the <directive module="mod_dir">DirectoryIndex</directive>
1646 <p><directive>LimitInternalRecursion</directive> prevents the server
1647 from crashing when entering an infinite loop of internal redirects or
1648 subrequests. Such loops are usually caused by misconfigurations.</p>
1650 <p>The directive stores two different limits, which are evaluated on
1651 per-request basis. The first <var>number</var> is the maximum number of
1652 internal redirects, that may follow each other. The second <var>number</var>
1653 determines, how deep subrequests may be nested. If you specify only one
1654 <var>number</var>, it will be assigned to both limits.</p>
1656 <example><title>Example</title>
1657 LimitInternalRecursion 5
1660 </directivesynopsis>
1663 <name>LimitRequestBody</name>
1664 <description>Restricts the total size of the HTTP request body sent
1665 from the client</description>
1666 <syntax>LimitRequestBody <var>bytes</var></syntax>
1667 <default>LimitRequestBody 0</default>
1668 <contextlist><context>server config</context><context>virtual host</context>
1669 <context>directory</context><context>.htaccess</context>
1671 <override>All</override>
1674 <p>This directive specifies the number of <var>bytes</var> from 0
1675 (meaning unlimited) to 2147483647 (2GB) that are allowed in a
1678 <p>The <directive>LimitRequestBody</directive> directive allows
1679 the user to set a limit on the allowed size of an HTTP request
1680 message body within the context in which the directive is given
1681 (server, per-directory, per-file or per-location). If the client
1682 request exceeds that limit, the server will return an error
1683 response instead of servicing the request. The size of a normal
1684 request message body will vary greatly depending on the nature of
1685 the resource and the methods allowed on that resource. CGI scripts
1686 typically use the message body for retrieving form information.
1687 Implementations of the <code>PUT</code> method will require
1688 a value at least as large as any representation that the server
1689 wishes to accept for that resource.</p>
1691 <p>This directive gives the server administrator greater
1692 control over abnormal client request behavior, which may be
1693 useful for avoiding some forms of denial-of-service
1696 <p>If, for example, you are permitting file upload to a particular
1697 location, and wish to limit the size of the uploaded file to 100K,
1698 you might use the following directive:</p>
1701 LimitRequestBody 102400
1705 </directivesynopsis>
1708 <name>LimitRequestFields</name>
1709 <description>Limits the number of HTTP request header fields that
1710 will be accepted from the client</description>
1711 <syntax>LimitRequestFields <var>number</var></syntax>
1712 <default>LimitRequestFields 100</default>
1713 <contextlist><context>server config</context></contextlist>
1716 <p><var>Number</var> is an integer from 0 (meaning unlimited) to
1717 32767. The default value is defined by the compile-time
1718 constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
1721 <p>The <directive>LimitRequestFields</directive> directive allows
1722 the server administrator to modify the limit on the number of
1723 request header fields allowed in an HTTP request. A server needs
1724 this value to be larger than the number of fields that a normal
1725 client request might include. The number of request header fields
1726 used by a client rarely exceeds 20, but this may vary among
1727 different client implementations, often depending upon the extent
1728 to which a user has configured their browser to support detailed
1729 content negotiation. Optional HTTP extensions are often expressed
1730 using request header fields.</p>
1732 <p>This directive gives the server administrator greater
1733 control over abnormal client request behavior, which may be
1734 useful for avoiding some forms of denial-of-service attacks.
1735 The value should be increased if normal clients see an error
1736 response from the server that indicates too many fields were
1737 sent in the request.</p>
1742 LimitRequestFields 50
1746 </directivesynopsis>
1749 <name>LimitRequestFieldSize</name>
1750 <description>Limits the size of the HTTP request header allowed from the
1751 client</description>
1752 <syntax>LimitRequestFieldsize <var>bytes</var></syntax>
1753 <default>LimitRequestFieldsize 8190</default>
1754 <contextlist><context>server config</context></contextlist>
1757 <p>This directive specifies the number of <var>bytes</var>
1758 that will be allowed in an HTTP request header.</p>
1760 <p>The <directive>LimitRequestFieldSize</directive> directive
1761 allows the server administrator to reduce or increase the limit
1762 on the allowed size of an HTTP request header field. A server
1763 needs this value to be large enough to hold any one header field
1764 from a normal client request. The size of a normal request header
1765 field will vary greatly among different client implementations,
1766 often depending upon the extent to which a user has configured
1767 their browser to support detailed content negotiation. SPNEGO
1768 authentication headers can be up to 12392 bytes.</p>
1770 <p>This directive gives the server administrator greater
1771 control over abnormal client request behavior, which may be
1772 useful for avoiding some forms of denial-of-service attacks.</p>
1777 LimitRequestFieldSize 4094
1780 <note>Under normal conditions, the value should not be changed from
1784 </directivesynopsis>
1787 <name>LimitRequestLine</name>
1788 <description>Limit the size of the HTTP request line that will be accepted
1789 from the client</description>
1790 <syntax>LimitRequestLine <var>bytes</var></syntax>
1791 <default>LimitRequestLine 8190</default>
1792 <contextlist><context>server config</context></contextlist>
1795 <p>This directive sets the number of <var>bytes</var> that will be
1796 allowed on the HTTP request-line.</p>
1798 <p>The <directive>LimitRequestLine</directive> directive allows
1799 the server administrator to reduce or increase the limit on the allowed size
1800 of a client's HTTP request-line. Since the request-line consists of the
1801 HTTP method, URI, and protocol version, the
1802 <directive>LimitRequestLine</directive> directive places a
1803 restriction on the length of a request-URI allowed for a request
1804 on the server. A server needs this value to be large enough to
1805 hold any of its resource names, including any information that
1806 might be passed in the query part of a <code>GET</code> request.</p>
1808 <p>This directive gives the server administrator greater
1809 control over abnormal client request behavior, which may be
1810 useful for avoiding some forms of denial-of-service attacks.</p>
1815 LimitRequestLine 4094
1818 <note>Under normal conditions, the value should not be changed from
1821 </directivesynopsis>
1824 <name>LimitXMLRequestBody</name>
1825 <description>Limits the size of an XML-based request body</description>
1826 <syntax>LimitXMLRequestBody <var>bytes</var></syntax>
1827 <default>LimitXMLRequestBody 1000000</default>
1828 <contextlist><context>server config</context><context>virtual host</context>
1829 <context>directory</context><context>.htaccess</context></contextlist>
1830 <override>All</override>
1833 <p>Limit (in bytes) on maximum size of an XML-based request
1834 body. A value of <code>0</code> will disable any checking.</p>
1839 LimitXMLRequestBody 0
1843 </directivesynopsis>
1845 <directivesynopsis type="section">
1846 <name>Location</name>
1847 <description>Applies the enclosed directives only to matching
1849 <syntax><Location
1850 <var>URL-path</var>|<var>URL</var>> ... </Location></syntax>
1851 <contextlist><context>server config</context><context>virtual host</context>
1855 <p>The <directive type="section">Location</directive> directive
1856 limits the scope of the enclosed directives by URL. It is similar to the
1857 <directive type="section" module="core">Directory</directive>
1858 directive, and starts a subsection which is terminated with a
1859 <code></Location></code> directive. <directive
1860 type="section">Location</directive> sections are processed in the
1861 order they appear in the configuration file, after the <directive
1862 type="section" module="core">Directory</directive> sections and
1863 <code>.htaccess</code> files are read, and after the <directive
1864 type="section" module="core">Files</directive> sections.</p>
1866 <p><directive type="section">Location</directive> sections operate
1867 completely outside the filesystem. This has several consequences.
1868 Most importantly, <directive type="section">Location</directive>
1869 directives should not be used to control access to filesystem
1870 locations. Since several different URLs may map to the same
1871 filesystem location, such access controls may by circumvented.</p>
1873 <note><title>When to use <directive
1874 type="section">Location</directive></title>
1876 <p>Use <directive type="section">Location</directive> to apply
1877 directives to content that lives outside the filesystem. For
1878 content that lives in the filesystem, use <directive
1879 type="section" module="core">Directory</directive> and <directive
1880 type="section" module="core">Files</directive>. An exception is
1881 <code><Location /></code>, which is an easy way to
1882 apply a configuration to the entire server.</p>
1885 <p>For all origin (non-proxy) requests, the URL to be matched is a
1886 URL-path of the form <code>/path/</code>. No scheme, hostname,
1887 port, or query string may be included. For proxy requests, the
1888 URL to be matched is of the form
1889 <code>scheme://servername/path</code>, and you must include the
1892 <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
1893 any single character, and <code>*</code> matches any sequences of
1896 <p><glossary ref="regex">Regular expressions</glossary>
1897 can also be used, with the addition of the
1898 <code>~</code> character. For example:</p>
1901 <Location ~ "/(extra|special)/data">
1904 <p>would match URLs that contained the substring <code>/extra/data</code>
1905 or <code>/special/data</code>. The directive <directive
1906 type="section" module="core">LocationMatch</directive> behaves
1907 identical to the regex version of <directive
1908 type="section">Location</directive>.</p>
1910 <p>The <directive type="section">Location</directive>
1911 functionality is especially useful when combined with the
1912 <directive module="core">SetHandler</directive>
1913 directive. For example, to enable status requests, but allow them
1914 only from browsers at <code>foo.com</code>, you might use:</p>
1917 <Location /status><br />
1919 SetHandler server-status<br />
1920 Order Deny,Allow<br />
1922 Allow from .foo.com<br />
1927 <note><title>Note about / (slash)</title>
1928 <p>The slash character has special meaning depending on where in a
1929 URL it appears. People may be used to its behavior in the filesystem
1930 where multiple adjacent slashes are frequently collapsed to a single
1931 slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
1932 <code>/home/foo</code>). In URL-space this is not necessarily true.
1933 The <directive type="section" module="core">LocationMatch</directive>
1934 directive and the regex version of <directive type="section"
1935 >Location</directive> require you to explicitly specify multiple
1936 slashes if that is your intention.</p>
1938 <p>For example, <code><LocationMatch ^/abc></code> would match
1939 the request URL <code>/abc</code> but not the request URL <code>
1940 //abc</code>. The (non-regex) <directive type="section"
1941 >Location</directive> directive behaves similarly when used for
1942 proxy requests. But when (non-regex) <directive type="section"
1943 >Location</directive> is used for non-proxy requests it will
1944 implicitly match multiple slashes with a single slash. For example,
1945 if you specify <code><Location /abc/def></code> and the
1946 request is to <code>/abc//def</code> then it will match.</p>
1949 <seealso><a href="../sections.html">How <Directory>, <Location>
1950 and <Files> sections work</a> for an explanation of how these
1951 different sections are combined when a request is received</seealso>
1952 </directivesynopsis>
1954 <directivesynopsis type="section">
1955 <name>LocationMatch</name>
1956 <description>Applies the enclosed directives only to regular-expression
1957 matching URLs</description>
1958 <syntax><LocationMatch
1959 <var>regex</var>> ... </LocationMatch></syntax>
1960 <contextlist><context>server config</context><context>virtual host</context>
1964 <p>The <directive type="section">LocationMatch</directive> directive
1965 limits the scope of the enclosed directives by URL, in an identical manner
1966 to <directive module="core" type="section">Location</directive>. However,
1967 it takes a <glossary ref="regex">regular expression</glossary>
1968 as an argument instead of a simple string. For example:</p>
1971 <LocationMatch "/(extra|special)/data">
1974 <p>would match URLs that contained the substring <code>/extra/data</code>
1975 or <code>/special/data</code>.</p>
1978 <seealso><a href="../sections.html">How <Directory>, <Location>
1979 and <Files> sections work</a> for an explanation of how these
1980 different sections are combined when a request is received</seealso>
1981 </directivesynopsis>
1984 <name>LogLevel</name>
1985 <description>Controls the verbosity of the ErrorLog</description>
1986 <syntax>LogLevel <var>level</var></syntax>
1987 <default>LogLevel warn</default>
1988 <contextlist><context>server config</context><context>virtual host</context>
1992 <p><directive>LogLevel</directive> adjusts the verbosity of the
1993 messages recorded in the error logs (see <directive
1994 module="core">ErrorLog</directive> directive). The following
1995 <var>level</var>s are available, in order of decreasing
1999 <columnspec><column width=".2"/><column width=".3"/><column width=".5"/>
2002 <th><strong>Level</strong> </th>
2004 <th><strong>Description</strong> </th>
2006 <th><strong>Example</strong> </th>
2010 <td><code>emerg</code> </td>
2012 <td>Emergencies - system is unusable.</td>
2014 <td>"Child cannot open lock file. Exiting"</td>
2018 <td><code>alert</code> </td>
2020 <td>Action must be taken immediately.</td>
2022 <td>"getpwuid: couldn't determine user name from uid"</td>
2026 <td><code>crit</code> </td>
2028 <td>Critical Conditions.</td>
2030 <td>"socket: Failed to get a socket, exiting child"</td>
2034 <td><code>error</code> </td>
2036 <td>Error conditions.</td>
2038 <td>"Premature end of script headers"</td>
2042 <td><code>warn</code> </td>
2044 <td>Warning conditions.</td>
2046 <td>"child process 1234 did not exit, sending another
2051 <td><code>notice</code> </td>
2053 <td>Normal but significant condition.</td>
2055 <td>"httpd: caught SIGBUS, attempting to dump core in
2060 <td><code>info</code> </td>
2062 <td>Informational.</td>
2064 <td>"Server seems busy, (you may need to increase
2065 StartServers, or Min/MaxSpareServers)..."</td>
2069 <td><code>debug</code> </td>
2071 <td>Debug-level messages</td>
2073 <td>"Opening config file ..."</td>
2077 <p>When a particular level is specified, messages from all
2078 other levels of higher significance will be reported as well.
2079 <em>E.g.</em>, when <code>LogLevel info</code> is specified,
2080 then messages with log levels of <code>notice</code> and
2081 <code>warn</code> will also be posted.</p>
2083 <p>Using a level of at least <code>crit</code> is
2092 <note><title>Note</title>
2093 <p>When logging to a regular file messages of the level
2094 <code>notice</code> cannot be suppressed and thus are always
2095 logged. However, this doesn't apply when logging is done
2096 using <code>syslog</code>.</p>
2099 </directivesynopsis>
2102 <name>MaxKeepAliveRequests</name>
2103 <description>Number of requests allowed on a persistent
2104 connection</description>
2105 <syntax>MaxKeepAliveRequests <var>number</var></syntax>
2106 <default>MaxKeepAliveRequests 100</default>
2107 <contextlist><context>server config</context><context>virtual host</context>
2111 <p>The <directive>MaxKeepAliveRequests</directive> directive
2112 limits the number of requests allowed per connection when
2113 <directive module="core" >KeepAlive</directive> is on. If it is
2114 set to <code>0</code>, unlimited requests will be allowed. We
2115 recommend that this setting be kept to a high value for maximum
2116 server performance.</p>
2121 MaxKeepAliveRequests 500
2124 </directivesynopsis>
2127 <name>NameVirtualHost</name>
2128 <description>Designates an IP address for name-virtual
2129 hosting</description>
2130 <syntax>NameVirtualHost <var>addr</var>[:<var>port</var>]</syntax>
2131 <contextlist><context>server config</context></contextlist>
2134 <p>The <directive>NameVirtualHost</directive> directive is a
2135 required directive if you want to configure <a
2136 href="../vhosts/">name-based virtual hosts</a>.</p>
2138 <p>Although <var>addr</var> can be hostname it is recommended
2139 that you always use an IP address, e.g.</p>
2142 NameVirtualHost 111.22.33.44
2145 <p>With the <directive>NameVirtualHost</directive> directive you
2146 specify the IP address on which the server will receive requests
2147 for the name-based virtual hosts. This will usually be the address
2148 to which your name-based virtual host names resolve. In cases
2149 where a firewall or other proxy receives the requests and forwards
2150 them on a different IP address to the server, you must specify the
2151 IP address of the physical interface on the machine which will be
2152 servicing the requests. If you have multiple name-based hosts on
2153 multiple addresses, repeat the directive for each address.</p>
2155 <note><title>Note</title>
2156 <p>Note, that the "main server" and any <code>_default_</code> servers
2157 will <strong>never</strong> be served for a request to a
2158 <directive>NameVirtualHost</directive> IP address (unless for some
2159 reason you specify <directive>NameVirtualHost</directive> but then
2160 don't define any <directive>VirtualHost</directive>s for that
2164 <p>Optionally you can specify a port number on which the
2165 name-based virtual hosts should be used, e.g.</p>
2168 NameVirtualHost 111.22.33.44:8080
2171 <p>IPv6 addresses must be enclosed in square brackets, as shown
2172 in the following example:</p>
2175 NameVirtualHost [fe80::a00:20ff:fea7:ccea]:8080
2178 <p>To receive requests on all interfaces, you can use an argument of
2185 <note><title>Argument to <directive type="section">VirtualHost</directive>
2187 <p>Note that the argument to the <directive
2188 type="section">VirtualHost</directive> directive must
2189 exactly match the argument to the <directive
2190 >NameVirtualHost</directive> directive.</p>
2193 NameVirtualHost 1.2.3.4<br />
2194 <VirtualHost 1.2.3.4><br />
2196 </VirtualHost><br />
2201 <seealso><a href="../vhosts/">Virtual Hosts
2202 documentation</a></seealso>
2204 </directivesynopsis>
2207 <name>Options</name>
2208 <description>Configures what features are available in a particular
2209 directory</description>
2211 [+|-]<var>option</var> [[+|-]<var>option</var>] ...</syntax>
2212 <default>Options All</default>
2213 <contextlist><context>server config</context><context>virtual host</context>
2214 <context>directory</context><context>.htaccess</context>
2216 <override>Options</override>
2219 <p>The <directive>Options</directive> directive controls which
2220 server features are available in a particular directory.</p>
2222 <p><var>option</var> can be set to <code>None</code>, in which
2223 case none of the extra features are enabled, or one or more of
2227 <dt><code>All</code></dt>
2229 <dd>All options except for <code>MultiViews</code>. This is the default
2232 <dt><code>ExecCGI</code></dt>
2235 Execution of CGI scripts using <module>mod_cgi</module>
2238 <dt><code>FollowSymLinks</code></dt>
2242 The server will follow symbolic links in this directory.
2244 <p>Even though the server follows the symlink it does <em>not</em>
2245 change the pathname used to match against <directive type="section"
2246 module="core">Directory</directive> sections.</p>
2247 <p>Note also, that this option <strong>gets ignored</strong> if set
2248 inside a <directive type="section" module="core">Location</directive>
2252 <dt><code>Includes</code></dt>
2255 Server-side includes provided by <module>mod_include</module>
2258 <dt><code>IncludesNOEXEC</code></dt>
2262 Server-side includes are permitted, but the <code>#exec
2263 cmd</code> and <code>#exec cgi</code> are disabled. It is still
2264 possible to <code>#include virtual</code> CGI scripts from
2265 <directive module="mod_alias">ScriptAlias</directive>ed
2268 <dt><code>Indexes</code></dt>
2271 If a URL which maps to a directory is requested, and there
2272 is no <directive module="mod_dir">DirectoryIndex</directive>
2273 (<em>e.g.</em>, <code>index.html</code>) in that directory, then
2274 <module>mod_autoindex</module> will return a formatted listing
2275 of the directory.</dd>
2277 <dt><code>MultiViews</code></dt>
2280 <a href="../content-negotiation.html">Content negotiated</a>
2281 "MultiViews" are allowed using
2282 <module>mod_negotiation</module>.</dd>
2284 <dt><code>SymLinksIfOwnerMatch</code></dt>
2286 <dd>The server will only follow symbolic links for which the
2287 target file or directory is owned by the same user id as the
2290 <note><title>Note</title> This option gets ignored if
2291 set inside a <directive module="core"
2292 type="section">Location</directive> section.</note>
2296 <p>Normally, if multiple <directive>Options</directive> could
2297 apply to a directory, then the most specific one is used and
2298 others are ignored; the options are not merged. (See <a
2299 href="../sections.html#mergin">how sections are merged</a>.)
2300 However if <em>all</em> the options on the
2301 <directive>Options</directive> directive are preceded by a
2302 <code>+</code> or <code>-</code> symbol, the options are
2303 merged. Any options preceded by a <code>+</code> are added to the
2304 options currently in force, and any options preceded by a
2305 <code>-</code> are removed from the options currently in
2308 <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>
2311 <Directory /web/docs><br />
2313 Options Indexes FollowSymLinks<br />
2315 </Directory><br />
2317 <Directory /web/docs/spec><br />
2319 Options Includes<br />
2324 <p>then only <code>Includes</code> will be set for the
2325 <code>/web/docs/spec</code> directory. However if the second
2326 <directive>Options</directive> directive uses the <code>+</code> and
2327 <code>-</code> symbols:</p>
2330 <Directory /web/docs><br />
2332 Options Indexes FollowSymLinks<br />
2334 </Directory><br />
2336 <Directory /web/docs/spec><br />
2338 Options +Includes -Indexes<br />
2343 <p>then the options <code>FollowSymLinks</code> and
2344 <code>Includes</code> are set for the <code>/web/docs/spec</code>
2347 <note><title>Note</title>
2348 <p>Using <code>-IncludesNOEXEC</code> or
2349 <code>-Includes</code> disables server-side includes completely
2350 regardless of the previous setting.</p>
2353 <p>The default in the absence of any other settings is
2354 <code>All</code>.</p>
2356 </directivesynopsis>
2359 <name>Require</name>
2360 <description>Selects which authenticated users can access
2361 a resource</description>
2362 <syntax>Require <var>entity-name</var> [<var>entity-name</var>] ...</syntax>
2363 <contextlist><context>directory</context><context>.htaccess</context>
2365 <override>AuthConfig</override>
2368 <p>This directive selects which authenticated users can access
2369 a resource. The allowed syntaxes are:</p>
2372 <dt><code>Require user <var>userid</var> [<var>userid</var>]
2374 <dd>Only the named users can access the resource.</dd>
2376 <dt><code>Require group <var>group-name</var> [<var>group-name</var>]
2378 <dd>Only users in the named groups can access the resource.</dd>
2380 <dt><code>Require valid-user</code></dt>
2381 <dd>All valid users can access the resource.</dd>
2384 <p><directive>Require</directive> must be accompanied by
2385 <directive module="core">AuthName</directive> and <directive
2386 module="core">AuthType</directive> directives, and directives such
2387 as <directive module="mod_authn_file">AuthUserFile</directive>
2388 and <directive module="mod_authz_groupfile">AuthGroupFile</directive> (to
2389 define users and groups) in order to work correctly. Example:</p>
2392 AuthType Basic<br />
2393 AuthName "Restricted Resource"<br />
2394 AuthUserFile /web/users<br />
2395 AuthGroupFile /web/groups<br />
2399 <p>Access controls which are applied in this way are effective for
2400 <strong>all</strong> methods. <strong>This is what is normally
2401 desired.</strong> If you wish to apply access controls only to
2402 specific methods, while leaving other methods unprotected, then
2403 place the <directive>Require</directive> statement into a
2404 <directive module="core" type="section">Limit</directive>
2407 <seealso><directive module="core">Satisfy</directive></seealso>
2408 <seealso><module>mod_authz_host</module></seealso>
2409 </directivesynopsis>
2412 <name>RLimitCPU</name>
2413 <description>Limits the CPU consumption of processes launched
2414 by Apache children</description>
2415 <syntax>RLimitCPU <var>seconds</var>|max [<var>seconds</var>|max]</syntax>
2416 <default>Unset; uses operating system defaults</default>
2417 <contextlist><context>server config</context><context>virtual host</context>
2418 <context>directory</context><context>.htaccess</context></contextlist>
2419 <override>All</override>
2422 <p>Takes 1 or 2 parameters. The first parameter sets the soft
2423 resource limit for all processes and the second parameter sets
2424 the maximum resource limit. Either parameter can be a number,
2425 or <code>max</code> to indicate to the server that the limit should
2426 be set to the maximum allowed by the operating system
2427 configuration. Raising the maximum resource limit requires that
2428 the server is running as <code>root</code>, or in the initial startup
2431 <p>This applies to processes forked off from Apache children
2432 servicing requests, not the Apache children themselves. This
2433 includes CGI scripts and SSI exec commands, but not any
2434 processes forked off from the Apache parent such as piped
2437 <p>CPU resource limits are expressed in seconds per
2440 <seealso><directive module="core">RLimitMEM</directive></seealso>
2441 <seealso><directive module="core">RLimitNPROC</directive></seealso>
2442 </directivesynopsis>
2445 <name>RLimitMEM</name>
2446 <description>Limits the memory consumption of processes launched
2447 by Apache children</description>
2448 <syntax>RLimitMEM <var>bytes</var>|max [<var>bytes</var>|max]</syntax>
2449 <default>Unset; uses operating system defaults</default>
2450 <contextlist><context>server config</context><context>virtual host</context>
2451 <context>directory</context><context>.htaccess</context></contextlist>
2452 <override>All</override>
2455 <p>Takes 1 or 2 parameters. The first parameter sets the soft
2456 resource limit for all processes and the second parameter sets
2457 the maximum resource limit. Either parameter can be a number,
2458 or <code>max</code> to indicate to the server that the limit should
2459 be set to the maximum allowed by the operating system
2460 configuration. Raising the maximum resource limit requires that
2461 the server is running as <code>root</code>, or in the initial startup
2464 <p>This applies to processes forked off from Apache children
2465 servicing requests, not the Apache children themselves. This
2466 includes CGI scripts and SSI exec commands, but not any
2467 processes forked off from the Apache parent such as piped
2470 <p>Memory resource limits are expressed in bytes per
2473 <seealso><directive module="core">RLimitCPU</directive></seealso>
2474 <seealso><directive module="core">RLimitNPROC</directive></seealso>
2475 </directivesynopsis>
2478 <name>RLimitNPROC</name>
2479 <description>Limits the number of processes that can be launched by
2480 processes launched by Apache children</description>
2481 <syntax>RLimitNPROC <var>number</var>|max [<var>number</var>|max]</syntax>
2482 <default>Unset; uses operating system defaults</default>
2483 <contextlist><context>server config</context><context>virtual host</context>
2484 <context>directory</context><context>.htaccess</context></contextlist>
2485 <override>All</override>
2488 <p>Takes 1 or 2 parameters. The first parameter sets the soft
2489 resource limit for all processes and the second parameter sets
2490 the maximum resource limit. Either parameter can be a number,
2491 or <code>max</code> to indicate to the server that the limit
2492 should be set to the maximum allowed by the operating system
2493 configuration. Raising the maximum resource limit requires that
2494 the server is running as <code>root</code>, or in the initial startup
2497 <p>This applies to processes forked off from Apache children
2498 servicing requests, not the Apache children themselves. This
2499 includes CGI scripts and SSI exec commands, but not any
2500 processes forked off from the Apache parent such as piped
2503 <p>Process limits control the number of processes per user.</p>
2505 <note><title>Note</title>
2506 <p>If CGI processes are <strong>not</strong> running
2507 under user ids other than the web server user id, this directive
2508 will limit the number of processes that the server itself can
2509 create. Evidence of this situation will be indicated by
2510 <strong><code>cannot fork</code></strong> messages in the
2511 <code>error_log</code>.</p>
2514 <seealso><directive module="core">RLimitMEM</directive></seealso>
2515 <seealso><directive module="core">RLimitCPU</directive></seealso>
2516 </directivesynopsis>
2519 <name>Satisfy</name>
2520 <description>Interaction between host-level access control and
2521 user authentication</description>
2522 <syntax>Satisfy Any|All</syntax>
2523 <default>Satisfy All</default>
2524 <contextlist><context>directory</context><context>.htaccess</context>
2526 <override>AuthConfig</override>
2527 <compatibility>Influenced by <directive module="core" type="section"
2528 >Limit</directive> and <directive module="core"
2529 type="section">LimitExcept</directive> in version 2.0.51 and
2530 later</compatibility>
2533 <p>Access policy if both <directive
2534 module="mod_authz_host">Allow</directive> and <directive
2535 module="core">Require</directive> used. The parameter can be
2536 either <code>All</code> or <code>Any</code>. This directive is only
2537 useful if access to a particular area is being restricted by both
2538 username/password <em>and</em> client host address. In this case
2539 the default behavior (<code>All</code>) is to require that the client
2540 passes the address access restriction <em>and</em> enters a valid
2541 username and password. With the <code>Any</code> option the client will be
2542 granted access if they either pass the host restriction or enter a
2543 valid username and password. This can be used to password restrict
2544 an area, but to let clients from particular addresses in without
2545 prompting for a password.</p>
2547 <p>For example, if you wanted to let people on your network have
2548 unrestricted access to a portion of your website, but require that
2549 people outside of your network provide a password, you could use a
2550 configuration similar to the following:</p>
2553 Require valid-user<br />
2554 Allow from 192.168.1<br />
2558 <p>Since version 2.0.51 <directive>Satisfy</directive> directives can
2559 be restricted to particular methods by <directive module="core"
2560 type="section">Limit</directive> and <directive module="core" type="section"
2561 >LimitExcept</directive> sections.</p>
2563 <seealso><directive module="mod_authz_host">Allow</directive></seealso>
2564 <seealso><directive module="core">Require</directive></seealso>
2565 </directivesynopsis>
2568 <name>ScriptInterpreterSource</name>
2569 <description>Technique for locating the interpreter for CGI
2570 scripts</description>
2571 <syntax>ScriptInterpreterSource Registry|Registry-Strict|Script</syntax>
2572 <default>ScriptInterpreterSource Script</default>
2573 <contextlist><context>server config</context><context>virtual host</context>
2574 <context>directory</context><context>.htaccess</context></contextlist>
2575 <override>FileInfo</override>
2576 <compatibility>Win32 only;
2577 option <code>Registry-Strict</code> is available in Apache 2.0 and
2578 later</compatibility>
2581 <p>This directive is used to control how Apache finds the
2582 interpreter used to run CGI scripts. The default setting is
2583 <code>Script</code>. This causes Apache to use the interpreter pointed to
2584 by the shebang line (first line, starting with <code>#!</code>) in the
2585 script. On Win32 systems this line usually looks like:</p>
2588 #!C:/Perl/bin/perl.exe
2591 <p>or, if <code>perl</code> is in the <code>PATH</code>, simply:</p>
2597 <p>Setting <code>ScriptInterpreterSource Registry</code> will
2598 cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
2599 searched using the script file extension (e.g., <code>.pl</code>) as a
2600 search key. The command defined by the registry subkey
2601 <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
2602 <code>Shell\Open\Command</code> is used to open the script file. If the
2603 registry keys cannot be found, Apache falls back to the behavior of the
2604 <code>Script</code> option.</p>
2606 <note type="warning"><title>Security</title>
2607 <p>Be careful when using <code>ScriptInterpreterSource
2608 Registry</code> with <directive
2609 module="mod_alias">ScriptAlias</directive>'ed directories, because
2610 Apache will try to execute <strong>every</strong> file within this
2611 directory. The <code>Registry</code> setting may cause undesired
2612 program calls on files which are typically not executed. For
2613 example, the default open command on <code>.htm</code> files on
2614 most Windows systems will execute Microsoft Internet Explorer, so
2615 any HTTP request for an <code>.htm</code> file existing within the
2616 script directory would start the browser in the background on the
2617 server. This is a good way to crash your system within a minute or
2621 <p>The option <code>Registry-Strict</code> which is new in Apache
2622 2.0 does the same thing as <code>Registry</code> but uses only the
2623 subkey <code>Shell\ExecCGI\Command</code>. The
2624 <code>ExecCGI</code> key is not a common one. It must be
2625 configured manually in the windows registry and hence prevents
2626 accidental program calls on your system.</p>
2628 </directivesynopsis>
2631 <name>ServerAdmin</name>
2632 <description>Email address that the server includes in error
2633 messages sent to the client</description>
2634 <syntax>ServerAdmin <var>email-address</var>|<var>URL</var></syntax>
2635 <contextlist><context>server config</context><context>virtual host</context>
2639 <p>The <directive>ServerAdmin</directive> sets the contact address
2640 that the server includes in any error messages it returns to the
2641 client. If the <code>httpd</code> doesn't recognize the supplied argument
2643 assumes, that it's an <var>email-address</var> and prepends it with
2644 <code>mailto:</code> in hyperlink targets. However, it's recommended to
2645 actually use an email address, since there are a lot of CGI scripts that
2646 make that assumption. If you want to use an URL, it should point to another
2647 server under your control. Otherwise users may not be able to contact you in
2650 <p>It may be worth setting up a dedicated address for this, e.g.</p>
2653 ServerAdmin www-admin@foo.example.com
2655 <p>as users do not always mention that they are talking about the
2658 </directivesynopsis>
2661 <name>ServerAlias</name>
2662 <description>Alternate names for a host used when matching requests
2663 to name-virtual hosts</description>
2664 <syntax>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</syntax>
2665 <contextlist><context>virtual host</context></contextlist>
2668 <p>The <directive>ServerAlias</directive> directive sets the
2669 alternate names for a host, for use with <a
2670 href="../vhosts/name-based.html">name-based virtual hosts</a>.</p>
2673 <VirtualHost *><br />
2674 ServerName server.domain.com<br />
2675 ServerAlias server server2.domain.com server2<br />
2677 </VirtualHost>
2680 <seealso><a href="../vhosts/">Apache Virtual Host documentation</a></seealso>
2681 </directivesynopsis>
2684 <name>ServerName</name>
2685 <description>Hostname and port that the server uses to identify
2686 itself</description>
2687 <syntax>ServerName <var>fully-qualified-domain-name</var>[:<var>port</var>]</syntax>
2688 <contextlist><context>server config</context><context>virtual host</context>
2690 <compatibility>In version 2.0, this
2691 directive supersedes the functionality of the <directive>Port</directive>
2692 directive from version 1.3.</compatibility>
2695 <p>The <directive>ServerName</directive> directive sets the hostname and
2696 port that the server uses to identify itself. This is used when
2697 creating redirection URLs. For example, if the name of the
2698 machine hosting the web server is <code>simple.example.com</code>,
2699 but the machine also has the DNS alias <code>www.example.com</code>
2700 and you wish the web server to be so identified, the following
2701 directive should be used:</p>
2704 ServerName www.example.com:80
2707 <p>If no <directive>ServerName</directive> is specified, then the
2708 server attempts to deduce the hostname by performing a reverse
2709 lookup on the IP address. If no port is specified in the
2710 <directive>ServerName</directive>, then the server will use the port
2712 request. For optimal reliability and predictability, you should
2713 specify an explicit hostname and port using the
2714 <directive>ServerName</directive> directive.</p>
2716 <p>If you are using <a
2717 href="../vhosts/name-based.html">name-based virtual hosts</a>,
2718 the <directive>ServerName</directive> inside a
2719 <directive type="section" module="core">VirtualHost</directive>
2720 section specifies what hostname must appear in the request's
2721 <code>Host:</code> header to match this virtual host.</p>
2723 <p>See the description of the
2724 <directive module="core">UseCanonicalName</directive> directive for
2725 settings which determine whether self-referential URL's (e.g., by the
2726 <module>mod_dir</module> module) will refer to the
2727 specified port, or to the port number given in the client's request.
2731 <seealso><a href="../dns-caveats.html">Issues Regarding DNS and
2732 Apache</a></seealso>
2733 <seealso><a href="../vhosts/">Apache virtual host
2734 documentation</a></seealso>
2735 <seealso><directive module="core">UseCanonicalName</directive></seealso>
2736 <seealso><directive module="core">NameVirtualHost</directive></seealso>
2737 <seealso><directive module="core">ServerAlias</directive></seealso>
2738 </directivesynopsis>
2741 <name>ServerPath</name>
2742 <description>Legacy URL pathname for a name-based virtual host that
2743 is accessed by an incompatible browser</description>
2744 <syntax>ServerPath <var>URL-path</var></syntax>
2745 <contextlist><context>virtual host</context></contextlist>
2748 <p>The <directive>ServerPath</directive> directive sets the legacy
2749 URL pathname for a host, for use with <a
2750 href="../vhosts/">name-based virtual hosts</a>.</p>
2752 <seealso><a href="../vhosts/">Apache Virtual Host documentation</a></seealso>
2753 </directivesynopsis>
2756 <name>ServerRoot</name>
2757 <description>Base directory for the server installation</description>
2758 <syntax>ServerRoot <var>directory-path</var></syntax>
2759 <default>ServerRoot /usr/local/apache</default>
2760 <contextlist><context>server config</context></contextlist>
2763 <p>The <directive>ServerRoot</directive> directive sets the
2764 directory in which the server lives. Typically it will contain the
2765 subdirectories <code>conf/</code> and <code>logs/</code>. Relative
2766 paths in other configuration directives (such as <directive
2767 module="core">Include</directive> or <directive
2768 module="mod_so">LoadModule</directive>, for example) are taken as
2769 relative to this directory.</p>
2771 <example><title>Example</title>
2772 ServerRoot /home/httpd
2776 <seealso><a href="../invoking.html">the <code>-d</code>
2777 option to <code>httpd</code></a></seealso>
2778 <seealso><a href="../misc/security_tips.html#serverroot">the
2779 security tips</a> for information on how to properly set
2780 permissions on the <directive>ServerRoot</directive></seealso>
2781 </directivesynopsis>
2784 <name>ServerSignature</name>
2785 <description>Configures the footer on server-generated documents</description>
2786 <syntax>ServerSignature On|Off|EMail</syntax>
2787 <default>ServerSignature Off</default>
2788 <contextlist><context>server config</context><context>virtual host</context>
2789 <context>directory</context><context>.htaccess</context>
2791 <override>All</override>
2794 <p>The <directive>ServerSignature</directive> directive allows the
2795 configuration of a trailing footer line under server-generated
2796 documents (error messages, <module>mod_proxy</module> ftp directory
2797 listings, <module>mod_info</module> output, ...). The reason why you
2798 would want to enable such a footer line is that in a chain of proxies,
2799 the user often has no possibility to tell which of the chained servers
2800 actually produced a returned error message.</p>
2802 <p>The <code>Off</code>
2803 setting, which is the default, suppresses the footer line (and is
2804 therefore compatible with the behavior of Apache-1.2 and
2805 below). The <code>On</code> setting simply adds a line with the
2806 server version number and <directive
2807 module="core">ServerName</directive> of the serving virtual host,
2808 and the <code>EMail</code> setting additionally creates a
2809 "mailto:" reference to the <directive
2810 module="core">ServerAdmin</directive> of the referenced
2813 <p>After version 2.0.44, the details of the server version number
2814 presented are controlled by the <directive
2815 module="core">ServerTokens</directive> directive.</p>
2817 <seealso><directive module="core">ServerTokens</directive></seealso>
2818 </directivesynopsis>
2821 <name>ServerTokens</name>
2822 <description>Configures the <code>Server</code> HTTP response
2823 header</description>
2824 <syntax>ServerTokens Major|Minor|Min[imal]|Prod[uctOnly]|OS|Full</syntax>
2825 <default>ServerTokens Full</default>
2826 <contextlist><context>server config</context></contextlist>
2829 <p>This directive controls whether <code>Server</code> response
2830 header field which is sent back to clients includes a
2831 description of the generic OS-type of the server as well as
2832 information about compiled-in modules.</p>
2835 <dt><code>ServerTokens Prod[uctOnly]</code></dt>
2837 <dd>Server sends (<em>e.g.</em>): <code>Server:
2840 <dt><code>ServerTokens Major</code></dt>
2842 <dd>Server sends (<em>e.g.</em>): <code>Server:
2843 Apache/2</code></dd>
2845 <dt><code>ServerTokens Minor</code></dt>
2847 <dd>Server sends (<em>e.g.</em>): <code>Server:
2848 Apache/2.0</code></dd>
2850 <dt><code>ServerTokens Min[imal]</code></dt>
2852 <dd>Server sends (<em>e.g.</em>): <code>Server:
2853 Apache/2.0.41</code></dd>
2855 <dt><code>ServerTokens OS</code></dt>
2857 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.0.41
2860 <dt><code>ServerTokens Full</code> (or not specified)</dt>
2862 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.0.41
2863 (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
2866 <p>This setting applies to the entire server, and cannot be
2867 enabled or disabled on a virtualhost-by-virtualhost basis.</p>
2869 <p>After version 2.0.44, this directive also controls the
2870 information presented by the <directive
2871 module="core">ServerSignature</directive> directive.</p>
2873 <seealso><directive module="core">ServerSignature</directive></seealso>
2874 </directivesynopsis>
2877 <name>SetHandler</name>
2878 <description>Forces all matching files to be processed by a
2879 handler</description>
2880 <syntax>SetHandler <var>handler-name</var>|None</syntax>
2881 <contextlist><context>server config</context><context>virtual host</context>
2882 <context>directory</context><context>.htaccess</context>
2884 <override>FileInfo</override>
2885 <compatibility>Moved into the core in Apache 2.0</compatibility>
2888 <p>When placed into an <code>.htaccess</code> file or a
2889 <directive type="section" module="core">Directory</directive> or
2890 <directive type="section" module="core">Location</directive>
2891 section, this directive forces all matching files to be parsed
2892 through the <a href="../handler.html">handler</a> given by
2893 <var>handler-name</var>. For example, if you had a directory you
2894 wanted to be parsed entirely as imagemap rule files, regardless
2895 of extension, you might put the following into an
2896 <code>.htaccess</code> file in that directory:</p>
2899 SetHandler imap-file
2902 <p>Another example: if you wanted to have the server display a
2903 status report whenever a URL of
2904 <code>http://servername/status</code> was called, you might put
2905 the following into <code>httpd.conf</code>:</p>
2908 <Location /status><br />
2910 SetHandler server-status<br />
2915 <p>You can override an earlier defined <directive>SetHandler</directive>
2916 directive by using the value <code>None</code>.</p>
2919 <seealso><directive module="mod_mime">AddHandler</directive></seealso>
2921 </directivesynopsis>
2924 <name>SetInputFilter</name>
2925 <description>Sets the filters that will process client requests and POST
2927 <syntax>SetInputFilter <var>filter</var>[;<var>filter</var>...]</syntax>
2928 <contextlist><context>server config</context><context>virtual host</context>
2929 <context>directory</context><context>.htaccess</context>
2931 <override>FileInfo</override>
2934 <p>The <directive>SetInputFilter</directive> directive sets the
2935 filter or filters which will process client requests and POST
2936 input when they are received by the server. This is in addition to
2937 any filters defined elsewhere, including the
2938 <directive module="mod_mime">AddInputFilter</directive>
2941 <p>If more than one filter is specified, they must be separated
2942 by semicolons in the order in which they should process the
2945 <seealso><a href="../filter.html">Filters</a> documentation</seealso>
2946 </directivesynopsis>
2949 <name>SetOutputFilter</name>
2950 <description>Sets the filters that will process responses from the
2951 server</description>
2952 <syntax>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</syntax>
2953 <contextlist><context>server config</context><context>virtual host</context>
2954 <context>directory</context><context>.htaccess</context>
2956 <override>FileInfo</override>
2959 <p>The <directive>SetOutputFilter</directive> directive sets the filters
2960 which will process responses from the server before they are
2961 sent to the client. This is in addition to any filters defined
2962 elsewhere, including the
2963 <directive module="mod_mime">AddOutputFilter</directive>
2966 <p>For example, the following configuration will process all files
2967 in the <code>/www/data/</code> directory for server-side
2971 <Directory /www/data/><br />
2973 SetOutputFilter INCLUDES<br />
2978 <p>If more than one filter is specified, they must be separated
2979 by semicolons in the order in which they should process the
2982 <seealso><a href="../filter.html">Filters</a> documentation</seealso>
2983 </directivesynopsis>
2986 <name>TimeOut</name>
2987 <description>Amount of time the server will wait for
2988 certain events before failing a request</description>
2989 <syntax>TimeOut <var>seconds</var></syntax>
2990 <default>TimeOut 300</default>
2991 <contextlist><context>server config</context></contextlist>
2994 <p>The <directive>TimeOut</directive> directive currently defines
2995 the amount of time Apache will wait for three things:</p>
2998 <li>The total amount of time it takes to receive a GET
3001 <li>The amount of time between receipt of TCP packets on a
3002 POST or PUT request.</li>
3004 <li>The amount of time between ACKs on transmissions of TCP
3005 packets in responses.</li>
3008 <p>We plan on making these separately configurable at some point
3009 down the road. The timer used to default to 1200 before 1.2,
3010 but has been lowered to 300 which is still far more than
3011 necessary in most situations. It is not set any lower by
3012 default because there may still be odd places in the code where
3013 the timer is not reset when a packet is sent. </p>
3015 </directivesynopsis>
3018 <name>TraceEnable</name>
3019 <description>Determines the behaviour on <code>TRACE</code>
3020 requests</description>
3021 <syntax>TraceEnable <var>[on|off|extended]</var></syntax>
3022 <default>TraceEnable on</default>
3023 <contextlist><context>server config</context></contextlist>
3024 <compatibility>Available in Apache 1.3.34, 2.0.55 and later</compatibility>
3027 <p>This directive overrides the behavior of <code>TRACE</code> for both
3028 the core server and <module>mod_proxy</module>. The default
3029 <code>TraceEnable on</code> permits <code>TRACE</code> requests per
3030 RFC 2616, which disallows any request body to accompany the request.
3031 <code>TraceEnable off</code> causes the core server and
3032 <module>mod_proxy</module> to return a <code>405</code> (Method not
3033 allowed) error to the client.</p>
3035 <p>Finally, for testing and diagnostic purposes only, request
3036 bodies may be allowed using the non-compliant <code>TraceEnable
3037 extended</code> directive. The core (as an origin server) will
3038 restrict the request body to 64k (plus 8k for chunk headers if
3039 <code>Transfer-Encoding: chunked</code> is used). The core will
3040 reflect the full headers and all chunk headers with the response
3041 body. As a proxy server, the request body is not restricted to 64k.</p>
3043 </directivesynopsis>
3046 <name>UseCanonicalName</name>
3047 <description>Configures how the server determines its own name and
3049 <syntax>UseCanonicalName On|Off|DNS</syntax>
3050 <default>UseCanonicalName Off</default>
3051 <contextlist><context>server config</context><context>virtual host</context>
3052 <context>directory</context></contextlist>
3055 <p>In many situations Apache must construct a <em>self-referential</em>
3056 URL -- that is, a URL that refers back to the same server. With
3057 <code>UseCanonicalName On</code> Apache will use the hostname and port
3058 specified in the <directive module="core">ServerName</directive>
3059 directive to construct the canonical name for the server. This name
3060 is used in all self-referential URLs, and for the values of
3061 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>
3063 <p>With <code>UseCanonicalName Off</code> Apache will form
3064 self-referential URLs using the hostname and port supplied by
3065 the client if any are supplied (otherwise it will use the
3066 canonical name, as defined above). These values are the same
3067 that are used to implement <a
3068 href="../vhosts/name-based.html">name based virtual hosts</a>,
3069 and are available with the same clients. The CGI variables
3070 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
3071 constructed from the client supplied values as well.</p>
3073 <p>An example where this may be useful is on an intranet server
3074 where you have users connecting to the machine using short
3075 names such as <code>www</code>. You'll notice that if the users
3076 type a shortname, and a URL which is a directory, such as
3077 <code>http://www/splat</code>, <em>without the trailing
3078 slash</em> then Apache will redirect them to
3079 <code>http://www.domain.com/splat/</code>. If you have
3080 authentication enabled, this will cause the user to have to
3081 authenticate twice (once for <code>www</code> and once again
3082 for <code>www.domain.com</code> -- see <a
3083 href="http://httpd.apache.org/docs/misc/FAQ.html#prompted-twice">the
3084 FAQ on this subject for more information</a>). But if
3085 <directive>UseCanonicalName</directive> is set <code>Off</code>, then
3086 Apache will redirect to <code>http://www/splat/</code>.</p>
3088 <p>There is a third option, <code>UseCanonicalName DNS</code>,
3089 which is intended for use with mass IP-based virtual hosting to
3090 support ancient clients that do not provide a
3091 <code>Host:</code> header. With this option Apache does a
3092 reverse DNS lookup on the server IP address that the client
3093 connected to in order to work out self-referential URLs.</p>
3095 <note type="warning"><title>Warning</title>
3096 <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>
3097 they may be broken by this option. The client is essentially free
3098 to give whatever value they want as a hostname. But if the CGI is
3099 only using <code>SERVER_NAME</code> to construct self-referential URLs
3100 then it should be just fine.</p>
3103 <seealso><directive module="core">ServerName</directive></seealso>
3104 <seealso><directive module="mpm_common">Listen</directive></seealso>
3105 </directivesynopsis>
3107 <directivesynopsis type="section">
3108 <name>VirtualHost</name>
3109 <description>Contains directives that apply only to a specific
3110 hostname or IP address</description>
3111 <syntax><VirtualHost
3112 <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
3113 ...> ... </VirtualHost></syntax>
3114 <contextlist><context>server config</context></contextlist>
3117 <p><directive type="section">VirtualHost</directive> and
3118 <code></VirtualHost></code> are used to enclose a group of
3119 directives that will apply only to a particular virtual host. Any
3120 directive that is allowed in a virtual host context may be
3121 used. When the server receives a request for a document on a
3122 particular virtual host, it uses the configuration directives
3123 enclosed in the <directive type="section">VirtualHost</directive>
3124 section. <var>Addr</var> can be:</p>
3127 <li>The IP address of the virtual host;</li>
3129 <li>A fully qualified domain name for the IP address of the
3132 <li>The character <code>*</code>, which is used only in combination with
3133 <code>NameVirtualHost *</code> to match all IP addresses; or</li>
3135 <li>The string <code>_default_</code>, which is used only
3136 with IP virtual hosting to catch unmatched IP addresses.</li>
3139 <example><title>Example</title>
3140 <VirtualHost 10.1.2.3><br />
3142 ServerAdmin webmaster@host.foo.com<br />
3143 DocumentRoot /www/docs/host.foo.com<br />
3144 ServerName host.foo.com<br />
3145 ErrorLog logs/host.foo.com-error_log<br />
3146 TransferLog logs/host.foo.com-access_log<br />
3148 </VirtualHost>
3152 <p>IPv6 addresses must be specified in square brackets because
3153 the optional port number could not be determined otherwise. An
3154 IPv6 example is shown below:</p>
3157 <VirtualHost [fe80::a00:20ff:fea7:ccea]><br />
3159 ServerAdmin webmaster@host.example.com<br />
3160 DocumentRoot /www/docs/host.example.com<br />
3161 ServerName host.example.com<br />
3162 ErrorLog logs/host.example.com-error_log<br />
3163 TransferLog logs/host.example.com-access_log<br />
3165 </VirtualHost>
3168 <p>Each Virtual Host must correspond to a different IP address,
3169 different port number or a different host name for the server,
3170 in the former case the server machine must be configured to
3171 accept IP packets for multiple addresses. (If the machine does
3172 not have multiple network interfaces, then this can be
3173 accomplished with the <code>ifconfig alias</code> command -- if
3174 your OS supports it).</p>
3176 <note><title>Note</title>
3177 <p>The use of <directive type="section">VirtualHost</directive> does
3178 <strong>not</strong> affect what addresses Apache listens on. You
3179 may need to ensure that Apache is listening on the correct addresses
3180 using <directive module="mpm_common">Listen</directive>.</p>
3183 <p>When using IP-based virtual hosting, the special name
3184 <code>_default_</code> can be specified in
3185 which case this virtual host will match any IP address that is
3186 not explicitly listed in another virtual host. In the absence
3187 of any <code>_default_</code> virtual host the "main" server config,
3188 consisting of all those definitions outside any VirtualHost
3189 section, is used when no IP-match occurs. (But note that any IP
3190 address that matches a <directive
3191 module="core">NameVirtualHost</directive> directive will use neither
3192 the "main" server config nor the <code>_default_</code> virtual host.
3193 See the <a href="../vhosts/name-based.html">name-based virtual hosting</a>
3194 documentation for further details.)</p>
3196 <p>You can specify a <code>:port</code> to change the port that is
3197 matched. If unspecified then it defaults to the same port as the
3198 most recent <directive module="mpm_common">Listen</directive>
3199 statement of the main server. You may also specify <code>:*</code>
3200 to match all ports on that address. (This is recommended when used
3201 with <code>_default_</code>.)</p>
3203 <note type="warning"><title>Security</title>
3204 <p>See the <a href="../misc/security_tips.html">security tips</a>
3205 document for details on why your security could be compromised if the
3206 directory where log files are stored is writable by anyone other
3207 than the user that starts the server.</p>
3210 <seealso><a href="../vhosts/">Apache Virtual Host documentation</a></seealso>
3211 <seealso><a href="../dns-caveats.html">Issues Regarding DNS and
3212 Apache</a></seealso>
3213 <seealso><a href="../bind.html">Setting
3214 which addresses and ports Apache uses</a></seealso>
3215 <seealso><a href="../sections.html">How <Directory>, <Location>
3216 and <Files> sections work</a> for an explanation of how these
3217 different sections are combined when a request is received</seealso>
3218 </directivesynopsis>