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10 The ASF licenses this file to You under the Apache License, Version 2.0
11 (the "License"); you may not use this file except in compliance with
12 the License. You may obtain a copy of the License at
14 http://www.apache.org/licenses/LICENSE-2.0
16 Unless required by applicable law or agreed to in writing, software
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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 nntp 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-handler</a>, generally accept
129 <code>PATH_INFO</code> by default.</dd>
132 <p>The primary purpose of the <code>AcceptPathInfo</code>
133 directive is to allow you to override the handler's choice of
134 accepting or rejecting <code>PATH_INFO</code>. This override is required,
135 for example, when you use a <a href="../filter.html">filter</a>, such
136 as <a href="mod_include.html">INCLUDES</a>, to generate content
137 based on <code>PATH_INFO</code>. The core handler would usually reject
138 the request, so you can use the following configuration to enable
142 <Files "mypaths.shtml"><br />
144 Options +Includes<br />
145 SetOutputFilter INCLUDES<br />
146 AcceptPathInfo On<br />
155 <name>AccessFileName</name>
156 <description>Name of the distributed configuration file</description>
157 <syntax>AccessFileName <var>filename</var> [<var>filename</var>] ...</syntax>
158 <default>AccessFileName .htaccess</default>
159 <contextlist><context>server config</context><context>virtual host</context>
163 <p>While processing a request the server looks for
164 the first existing configuration file from this list of names in
165 every directory of the path to the document, if distributed
166 configuration files are <a href="#allowoverride">enabled for that
167 directory</a>. For example:</p>
173 <p>before returning the document
174 <code>/usr/local/web/index.html</code>, the server will read
175 <code>/.acl</code>, <code>/usr/.acl</code>,
176 <code>/usr/local/.acl</code> and <code>/usr/local/web/.acl</code>
177 for directives, unless they have been disabled with</p>
180 <Directory /><br />
182 AllowOverride None<br />
187 <seealso><directive module="core">AllowOverride</directive></seealso>
188 <seealso><a href="../configuring.html">Configuration Files</a></seealso>
189 <seealso><a href="../howto/htaccess.html">.htaccess Files</a></seealso>
193 <name>AddDefaultCharset</name>
194 <description>Default charset parameter to be added when a response
195 content-type is <code>text/plain</code> or <code>text/html</code></description>
196 <syntax>AddDefaultCharset On|Off|<var>charset</var></syntax>
197 <default>AddDefaultCharset Off</default>
198 <contextlist><context>server config</context>
199 <context>virtual host</context><context>directory</context>
200 <context>.htaccess</context></contextlist>
201 <override>FileInfo</override>
204 <p>This directive specifies a default value for the media type
205 charset parameter (the name of a character encoding) to be added
206 to a response if and only if the response's content-type is either
207 <code>text/plain</code> or <code>text/html</code>. This should override
208 any charset specified in the body of the response via a <code>META</code>
209 element, though the exact behavior is often dependent on the user's client
210 configuration. A setting of <code>AddDefaultCharset Off</code>
211 disables this functionality. <code>AddDefaultCharset On</code> enables
212 a default charset of <code>iso-8859-1</code>. Any other value is assumed
213 to be the <var>charset</var> to be used, which should be one of the
214 <a href="http://www.iana.org/assignments/character-sets">IANA registered
215 charset values</a> for use in MIME media types.
219 AddDefaultCharset utf-8
222 <p><directive>AddDefaultCharset</directive> should only be used when all
223 of the text resources to which it applies are known to be in that
224 character encoding and it is too inconvenient to label their charset
225 individually. One such example is to add the charset parameter
226 to resources containing generated content, such as legacy CGI
227 scripts, that might be vulnerable to cross-site scripting attacks
228 due to user-provided data being included in the output. Note, however,
229 that a better solution is to just fix (or delete) those scripts, since
230 setting a default charset does not protect users that have enabled
231 the "auto-detect character encoding" feature on their browser.</p>
233 <seealso><directive module="mod_mime">AddCharset</directive></seealso>
237 <name>AddOutputFilterByType</name>
238 <description>assigns an output filter to a particular MIME-type</description>
239 <syntax>AddOutputFilterByType <var>filter</var>[;<var>filter</var>...]
240 <var>MIME-type</var> [<var>MIME-type</var>] ...</syntax>
241 <contextlist><context>server config</context>
242 <context>virtual host</context><context>directory</context>
243 <context>.htaccess</context></contextlist>
244 <override>FileInfo</override>
245 <compatibility>Available in Apache 2.0.33 and later; deprecated in Apache 2.1 and later</compatibility>
248 <p>This directive activates a particular output <a
249 href="../filter.html">filter</a> for a request depending on the
250 response <glossary>MIME-type</glossary>. Because of certain
251 problems discussed below, this directive is deprecated. The same
252 functionality is available using <module>mod_filter</module>.</p>
254 <p>The following example uses the <code>DEFLATE</code> filter, which
255 is provided by <module>mod_deflate</module>. It will compress all
256 output (either static or dynamic) which is labeled as
257 <code>text/html</code> or <code>text/plain</code> before it is sent
261 AddOutputFilterByType DEFLATE text/html text/plain
264 <p>If you want the content to be processed by more than one filter, their
265 names have to be separated by semicolons. It's also possible to use one
266 <directive>AddOutputFilterByType</directive> directive for each of
269 <p>The configuration below causes all script output labeled as
270 <code>text/html</code> to be processed at first by the
271 <code>INCLUDES</code> filter and then by the <code>DEFLATE</code>
275 <Location /cgi-bin/><br />
277 Options Includes<br />
278 AddOutputFilterByType INCLUDES;DEFLATE text/html<br />
283 <note type="warning"><title>Note</title>
284 <p>Enabling filters with <directive>AddOutputFilterByType</directive>
285 may fail partially or completely in some cases. For example, no
286 filters are applied if the <glossary>MIME-type</glossary> could not be determined and falls
287 back to the <directive module="core">DefaultType</directive> setting,
288 even if the <directive module="core">DefaultType</directive> is the
291 <p>However, if you want to make sure, that the filters will be
292 applied, assign the content type to a resource explicitly, for
293 example with <directive module="mod_mime">AddType</directive> or
294 <directive module="core">ForceType</directive>. Setting the
295 content type within a (non-nph) CGI script is also safe.</p>
297 <p>The by-type output filters are never applied on proxy requests.</p>
301 <seealso><directive module="mod_mime">AddOutputFilter</directive></seealso>
302 <seealso><directive module="core">SetOutputFilter</directive></seealso>
303 <seealso><a href="../filter.html">filters</a></seealso>
307 <name>AllowEncodedSlashes</name>
308 <description>Determines whether encoded path separators in URLs are allowed to
309 be passed through</description>
310 <syntax>AllowEncodedSlashes On|Off</syntax>
311 <default>AllowEncodedSlashes Off</default>
312 <contextlist><context>server config</context><context>virtual host</context>
314 <compatibility>Available in Apache 2.0.46 and later</compatibility>
317 <p>The <directive>AllowEncodedSlashes</directive> directive allows URLs
318 which contain encoded path separators (<code>%2F</code> for <code>/</code>
319 and additionally <code>%5C</code> for <code>\</code> on according systems)
320 to be used. Normally such URLs are refused with a 404 (Not found) error.</p>
322 <p>Turning <directive>AllowEncodedSlashes</directive> <code>On</code> is
323 mostly useful when used in conjunction with <code>PATH_INFO</code>.</p>
325 <note><title>Note</title>
326 <p>Allowing encoded slashes does <em>not</em> imply <em>decoding</em>.
327 Occurrences of <code>%2F</code> or <code>%5C</code> (<em>only</em> on
328 according systems) will be left as such in the otherwise decoded URL
332 <seealso><directive module="core">AcceptPathInfo</directive></seealso>
336 <name>AllowOverride</name>
337 <description>Types of directives that are allowed in
338 <code>.htaccess</code> files</description>
339 <syntax>AllowOverride All|None|<var>directive-type</var>
340 [<var>directive-type</var>] ...</syntax>
341 <default>AllowOverride All</default>
342 <contextlist><context>directory</context></contextlist>
345 <p>When the server finds an <code>.htaccess</code> file (as
346 specified by <directive module="core">AccessFileName</directive>)
347 it needs to know which directives declared in that file can override
348 earlier configuration directives.</p>
350 <note><title>Only available in <Directory> sections</title>
351 <directive>AllowOverride</directive> is valid only in
352 <directive type="section" module="core">Directory</directive>
353 sections specified without regular expressions, not in <directive
354 type="section" module="core">Location</directive>, <directive
355 module="core" type="section">DirectoryMatch</directive> or
356 <directive type="section" module="core">Files</directive> sections.
359 <p>When this directive is set to <code>None</code>, then
360 <a href="#accessfilename">.htaccess</a> files are completely ignored.
361 In this case, the server will not even attempt to read
362 <code>.htaccess</code> files in the filesystem.</p>
364 <p>When this directive is set to <code>All</code>, then any
365 directive which has the .htaccess <a
366 href="directive-dict.html#Context">Context</a> is allowed in
367 <code>.htaccess</code> files.</p>
369 <p>The <var>directive-type</var> can be one of the following
370 groupings of directives.</p>
377 Allow use of the authorization directives (<directive
378 module="mod_authn_dbm">AuthDBMGroupFile</directive>,
379 <directive module="mod_authn_dbm">AuthDBMUserFile</directive>,
380 <directive module="mod_authz_groupfile">AuthGroupFile</directive>,
381 <directive module="mod_authn_core">AuthName</directive>,
382 <directive module="mod_authn_core">AuthType</directive>, <directive
383 module="mod_authn_file">AuthUserFile</directive>, <directive
384 module="mod_authz_core">Require</directive>, <em>etc.</em>).</dd>
389 Allow use of the directives controlling document types (<directive
390 module="core">DefaultType</directive>, <directive
391 module="core">ErrorDocument</directive>, <directive
392 module="core">ForceType</directive>, <directive
393 module="mod_negotiation">LanguagePriority</directive>,
394 <directive module="core">SetHandler</directive>, <directive
395 module="core">SetInputFilter</directive>, <directive
396 module="core">SetOutputFilter</directive>, and
397 <module>mod_mime</module> Add* and Remove*
398 directives, <em>etc.</em>), document meta data (<directive
399 module="mod_headers">Header</directive>, <directive
400 module="mod_headers">RequestHeader</directive>, <directive
401 module="mod_setenvif">SetEnvIf</directive>, <directive
402 module="mod_setenvif">SetEnvIfNoCase</directive>, <directive
403 module="mod_setenvif">BrowserMatch</directive>, <directive
404 module="mod_usertrack">CookieExpires</directive>, <directive
405 module="mod_usertrack">CookieDomain</directive>, <directive
406 module="mod_usertrack">CookieStyle</directive>, <directive
407 module="mod_usertrack">CookieTracking</directive>, <directive
408 module="mod_usertrack">CookieName</directive>),
409 <module>mod_rewrite</module> directives <directive
410 module="mod_rewrite">RewriteEngine</directive>, <directive
411 module="mod_rewrite">RewriteOptions</directive>, <directive
412 module="mod_rewrite">RewriteBase</directive>, <directive
413 module="mod_rewrite">RewriteCond</directive>, <directive
414 module="mod_rewrite">RewriteRule</directive>) and
415 <directive module="mod_actions">Action</directive> from
416 <module>mod_actions</module>.
422 Allow use of the directives controlling directory indexing
424 module="mod_autoindex">AddDescription</directive>,
425 <directive module="mod_autoindex">AddIcon</directive>, <directive
426 module="mod_autoindex">AddIconByEncoding</directive>,
427 <directive module="mod_autoindex">AddIconByType</directive>,
428 <directive module="mod_autoindex">DefaultIcon</directive>, <directive
429 module="mod_dir">DirectoryIndex</directive>, <directive
430 module="mod_autoindex">FancyIndexing</directive>, <directive
431 module="mod_autoindex">HeaderName</directive>, <directive
432 module="mod_autoindex">IndexIgnore</directive>, <directive
433 module="mod_autoindex">IndexOptions</directive>, <directive
434 module="mod_autoindex">ReadmeName</directive>,
440 Allow use of the directives controlling host access (<directive
441 module="mod_authz_host">Allow</directive>, <directive
442 module="mod_authz_host">Deny</directive> and <directive
443 module="mod_authz_host">Order</directive>).</dd>
445 <dt>Options[=<var>Option</var>,...]</dt>
448 Allow use of the directives controlling specific directory
449 features (<directive module="core">Options</directive> and
450 <directive module="mod_include">XBitHack</directive>).
451 An equal sign may be given followed by a comma (but no spaces)
452 separated lists of options that may be set using the <directive
453 module="core">Options</directive> command.</dd>
459 AllowOverride AuthConfig Indexes
462 <p>In the example above all directives that are neither in the group
463 <code>AuthConfig</code> nor <code>Indexes</code> cause an internal
467 <seealso><directive module="core">AccessFileName</directive></seealso>
468 <seealso><a href="../configuring.html">Configuration Files</a></seealso>
469 <seealso><a href="../howto/htaccess.html">.htaccess Files</a></seealso>
473 <name>CGIMapExtension</name>
474 <description>Technique for locating the interpreter for CGI
475 scripts</description>
476 <syntax>CGIMapExtension <var>cgi-path</var> <var>.extension</var></syntax>
477 <contextlist><context>directory</context><context>.htaccess</context>
479 <override>FileInfo</override>
480 <compatibility>NetWare only</compatibility>
483 <p>This directive is used to control how Apache finds the
484 interpreter used to run CGI scripts. For example, setting
485 <code>CGIMapExtension sys:\foo.nlm .foo</code> will
486 cause all CGI script files with a <code>.foo</code> extension to
487 be passed to the FOO interpreter.</p>
492 <name>ContentDigest</name>
493 <description>Enables the generation of <code>Content-MD5</code> HTTP Response
494 headers</description>
495 <syntax>ContentDigest On|Off</syntax>
496 <default>ContentDigest Off</default>
497 <contextlist><context>server config</context><context>virtual host</context>
498 <context>directory</context><context>.htaccess</context>
500 <override>Options</override>
501 <status>Experimental</status>
504 <p>This directive enables the generation of
505 <code>Content-MD5</code> headers as defined in RFC1864
506 respectively RFC2068.</p>
508 <p>MD5 is an algorithm for computing a "message digest"
509 (sometimes called "fingerprint") of arbitrary-length data, with
510 a high degree of confidence that any alterations in the data
511 will be reflected in alterations in the message digest.</p>
513 <p>The <code>Content-MD5</code> header provides an end-to-end
514 message integrity check (MIC) of the entity-body. A proxy or
515 client may check this header for detecting accidental
516 modification of the entity-body in transit. Example header:</p>
519 Content-MD5: AuLb7Dp1rqtRtxz2m9kRpA==
522 <p>Note that this can cause performance problems on your server
523 since the message digest is computed on every request (the
524 values are not cached).</p>
526 <p><code>Content-MD5</code> is only sent for documents served
527 by the <module>core</module>, and not by any module. For example,
528 SSI documents, output from CGI scripts, and byte range responses
529 do not have this header.</p>
534 <name>DefaultType</name>
535 <description>MIME content-type that will be sent if the
536 server cannot determine a type in any other way</description>
537 <syntax>DefaultType <var>MIME-type</var></syntax>
538 <default>DefaultType text/plain</default>
539 <contextlist><context>server config</context><context>virtual host</context>
540 <context>directory</context><context>.htaccess</context>
542 <override>FileInfo</override>
545 <p>There will be times when the server is asked to provide a
546 document whose type cannot be determined by its <glossary
547 ref="mime-type">MIME types</glossary> mappings.</p>
549 <p>The server must inform the client of the content-type of the
550 document, so in the event of an unknown type it uses the
551 <code>DefaultType</code>. For example:</p>
554 DefaultType image/gif
557 <p>would be appropriate for a directory which contained many GIF
558 images with filenames missing the <code>.gif</code> extension.</p>
560 <p>Note that unlike <directive
561 module="core">ForceType</directive>, this directive only
562 provides the default mime-type. All other mime-type definitions,
563 including filename extensions, that might identify the media type
564 will override this default.</p>
570 <description>Define the existence of a variable</description>
571 <syntax>Define <var>parameter-name</var></syntax>
572 <contextlist><context>server config</context></contextlist>
575 <p>Equivalent to passing the <code>-D</code> argument to <a
576 href="../programs/httpd.html">httpd</a>.</p>
577 <p>This directive can be used to toggle the use of <directive module="core"
578 type="section">IfDefine</directive> sections without needing to alter
579 <code>-D</code> arguments in any startup scripts.</p>
583 <directivesynopsis type="section">
584 <name>Directory</name>
585 <description>Enclose a group of directives that apply only to the
586 named file-system directory and sub-directories</description>
587 <syntax><Directory <var>directory-path</var>>
588 ... </Directory></syntax>
589 <contextlist><context>server config</context><context>virtual host</context>
593 <p><directive type="section">Directory</directive> and
594 <code></Directory></code> are used to enclose a group of
595 directives that will apply only to the named directory and
596 sub-directories of that directory. Any directive that is allowed
597 in a directory context may be used. <var>Directory-path</var> is
598 either the full path to a directory, or a wild-card string using
599 Unix shell-style matching. In a wild-card string, <code>?</code> matches
600 any single character, and <code>*</code> matches any sequences of
601 characters. You may also use <code>[]</code> character ranges. None
602 of the wildcards match a `/' character, so <code><Directory
603 /*/public_html></code> will not match
604 <code>/home/user/public_html</code>, but <code><Directory
605 /home/*/public_html></code> will match. Example:</p>
608 <Directory /usr/local/httpd/htdocs><br />
610 Options Indexes FollowSymLinks<br />
616 <p>Be careful with the <var>directory-path</var> arguments:
617 They have to literally match the filesystem path which Apache uses
618 to access the files. Directives applied to a particular
619 <code><Directory></code> will not apply to files accessed from
620 that same directory via a different path, such as via different symbolic
624 <p><glossary ref="regex">Regular
625 expressions</glossary> can also be used, with the addition of the
626 <code>~</code> character. For example:</p>
629 <Directory ~ "^/www/.*/[0-9]{3}">
632 <p>would match directories in <code>/www/</code> that consisted of
635 <p>If multiple (non-regular expression) <directive
636 type="section">Directory</directive> sections
637 match the directory (or one of its parents) containing a document,
638 then the directives are applied in the order of shortest match
639 first, interspersed with the directives from the <a
640 href="#accessfilename">.htaccess</a> files. For example,
644 <Directory /><br />
646 AllowOverride None<br />
648 </Directory><br />
650 <Directory /home/><br />
652 AllowOverride FileInfo<br />
657 <p>for access to the document <code>/home/web/dir/doc.html</code>
661 <li>Apply directive <code>AllowOverride None</code>
662 (disabling <code>.htaccess</code> files).</li>
664 <li>Apply directive <code>AllowOverride FileInfo</code> (for
665 directory <code>/home</code>).</li>
667 <li>Apply any <code>FileInfo</code> directives in
668 <code>/home/.htaccess</code>, <code>/home/web/.htaccess</code> and
669 <code>/home/web/dir/.htaccess</code> in that order.</li>
672 <p>Regular expressions are not considered until after all of the
673 normal sections have been applied. Then all of the regular
674 expressions are tested in the order they appeared in the
675 configuration file. For example, with</p>
678 <Directory ~ abc$><br />
680 # ... directives here ...<br />
685 <p>the regular expression section won't be considered until after
686 all normal <directive type="section">Directory</directive>s and
687 <code>.htaccess</code> files have been applied. Then the regular
688 expression will match on <code>/home/abc/public_html/abc</code> and
689 the corresponding <directive type="section">Directory</directive> will
692 <p><strong>Note that the default Apache access for
693 <code><Directory /></code> is <code>Allow from All</code>.
694 This means that Apache will serve any file mapped from an URL. It is
695 recommended that you change this with a block such
699 <Directory /><br />
701 Order Deny,Allow<br />
707 <p><strong>and then override this for directories you
708 <em>want</em> accessible. See the <a
709 href="../misc/security_tips.html">Security Tips</a> page for more
710 details.</strong></p>
712 <p>The directory sections occur in the <code>httpd.conf</code> file.
713 <directive type="section">Directory</directive> directives
714 cannot nest, and cannot appear in a <directive module="core"
715 type="section">Limit</directive> or <directive module="core"
716 type="section">LimitExcept</directive> section.</p>
718 <seealso><a href="../sections.html">How <Directory>,
719 <Location> and <Files> sections work</a> for an
720 explanation of how these different sections are combined when a
721 request is received</seealso>
724 <directivesynopsis type="section">
725 <name>DirectoryMatch</name>
726 <description>Enclose directives that apply to
727 file-system directories matching a regular expression and their
728 subdirectories</description>
729 <syntax><DirectoryMatch <var>regex</var>>
730 ... </DirectoryMatch></syntax>
731 <contextlist><context>server config</context><context>virtual host</context>
735 <p><directive type="section">DirectoryMatch</directive> and
736 <code></DirectoryMatch></code> are used to enclose a group
737 of directives which will apply only to the named directory and
738 sub-directories of that directory, the same as <directive
739 module="core" type="section">Directory</directive>. However, it
740 takes as an argument a <glossary ref="regex">regular
741 expression</glossary>. For example:</p>
744 <DirectoryMatch "^/www/(.+/)?[0-9]{3}">
747 <p>would match directories in <code>/www/</code> that consisted of three
750 <seealso><directive type="section" module="core">Directory</directive> for
751 a description of how regular expressions are mixed in with normal
752 <directive type="section">Directory</directive>s</seealso>
754 href="../sections.html">How <Directory>, <Location> and
755 <Files> sections work</a> for an explanation of how these different
756 sections are combined when a request is received</seealso>
760 <name>DocumentRoot</name>
761 <description>Directory that forms the main document tree visible
762 from the web</description>
763 <syntax>DocumentRoot <var>directory-path</var></syntax>
764 <default>DocumentRoot /usr/local/apache/htdocs</default>
765 <contextlist><context>server config</context><context>virtual host</context>
769 <p>This directive sets the directory from which <program>httpd</program>
770 will serve files. Unless matched by a directive like <directive
771 module="mod_alias">Alias</directive>, the server appends the
772 path from the requested URL to the document root to make the
773 path to the document. Example:</p>
776 DocumentRoot /usr/web
780 <code>http://www.my.host.com/index.html</code> refers to
781 <code>/usr/web/index.html</code>. If the <var>directory-path</var> is
782 not absolute then it is assumed to be relative to the <directive
783 module="core">ServerRoot</directive>.</p>
785 <p>The <directive>DocumentRoot</directive> should be specified without
786 a trailing slash.</p>
788 <seealso><a href="../urlmapping.html#documentroot">Mapping URLs to Filesystem
789 Locations</a></seealso>
793 <name>EnableMMAP</name>
794 <description>Use memory-mapping to read files during delivery</description>
795 <syntax>EnableMMAP On|Off</syntax>
796 <default>EnableMMAP On</default>
797 <contextlist><context>server config</context><context>virtual host</context>
798 <context>directory</context><context>.htaccess</context>
800 <override>FileInfo</override>
803 <p>This directive controls whether the <program>httpd</program> may use
804 memory-mapping if it needs to read the contents of a file during
805 delivery. By default, when the handling of a request requires
806 access to the data within a file -- for example, when delivering a
807 server-parsed file using <module>mod_include</module> -- Apache
808 memory-maps the file if the OS supports it.</p>
810 <p>This memory-mapping sometimes yields a performance improvement.
811 But in some environments, it is better to disable the memory-mapping
812 to prevent operational problems:</p>
815 <li>On some multiprocessor systems, memory-mapping can reduce the
816 performance of the <program>httpd</program>.</li>
817 <li>With an NFS-mounted <directive module="core">DocumentRoot</directive>,
818 the <program>httpd</program> may crash due to a segmentation fault if a file
819 is deleted or truncated while the <program>httpd</program> has it
823 <p>For server configurations that are vulnerable to these problems,
824 you should disable memory-mapping of delivered files by specifying:</p>
830 <p>For NFS mounted files, this feature may be disabled explicitly for
831 the offending files by specifying:</p>
834 <Directory "/path-to-nfs-files">
844 <name>EnableSendfile</name>
845 <description>Use the kernel sendfile support to deliver files to the client</description>
846 <syntax>EnableSendfile On|Off</syntax>
847 <default>EnableSendfile On</default>
848 <contextlist><context>server config</context><context>virtual host</context>
849 <context>directory</context><context>.htaccess</context>
851 <override>FileInfo</override>
852 <compatibility>Available in version 2.0.44 and later</compatibility>
855 <p>This directive controls whether <program>httpd</program> may use the
856 sendfile support from the kernel to transmit file contents to the client.
857 By default, when the handling of a request requires no access
858 to the data within a file -- for example, when delivering a
859 static file -- Apache uses sendfile to deliver the file contents
860 without ever reading the file if the OS supports it.</p>
862 <p>This sendfile mechanism avoids separate read and send operations,
863 and buffer allocations. But on some platforms or within some
864 filesystems, it is better to disable this feature to avoid
865 operational problems:</p>
868 <li>Some platforms may have broken sendfile support that the build
869 system did not detect, especially if the binaries were built on
870 another box and moved to such a machine with broken sendfile
872 <li>On Linux the use of sendfile triggers TCP-checksum
873 offloading bugs on certain networking cards when using IPv6.</li>
874 <li>On Linux on Itanium, sendfile may be unable to handle files
875 over 2GB in size.</li>
876 <li>With a network-mounted <directive
877 module="core">DocumentRoot</directive> (e.g., NFS or SMB),
878 the kernel may be unable to serve the network file through
882 <p>For server configurations that are vulnerable to these problems,
883 you should disable this feature by specifying:</p>
889 <p>For NFS or SMB mounted files, this feature may be disabled explicitly
890 for the offending files by specifying:</p>
893 <Directory "/path-to-nfs-files">
903 <name>ErrorDocument</name>
904 <description>What the server will return to the client
905 in case of an error</description>
906 <syntax>ErrorDocument <var>error-code</var> <var>document</var></syntax>
907 <contextlist><context>server config</context><context>virtual host</context>
908 <context>directory</context><context>.htaccess</context>
910 <override>FileInfo</override>
911 <compatibility>Quoting syntax for text messages is different in Apache
915 <p>In the event of a problem or error, Apache can be configured
916 to do one of four things,</p>
919 <li>output a simple hardcoded error message</li>
921 <li>output a customized message</li>
923 <li>redirect to a local <var>URL-path</var> to handle the
926 <li>redirect to an external <var>URL</var> to handle the
930 <p>The first option is the default, while options 2-4 are
931 configured using the <directive>ErrorDocument</directive>
932 directive, which is followed by the HTTP response code and a URL
933 or a message. Apache will sometimes offer additional information
934 regarding the problem/error.</p>
936 <p>URLs can begin with a slash (/) for local web-paths (relative
937 to the <directive module="core">DocumentRoot</directive>), or be a
938 full URL which the client can resolve. Alternatively, a message
939 can be provided to be displayed by the browser. Examples:</p>
942 ErrorDocument 500 http://foo.example.com/cgi-bin/tester<br />
943 ErrorDocument 404 /cgi-bin/bad_urls.pl<br />
944 ErrorDocument 401 /subscription_info.html<br />
945 ErrorDocument 403 "Sorry can't allow you access today"
948 <p>Additionally, the special value <code>default</code> can be used
949 to specify Apache's simple hardcoded message. While not required
950 under normal circumstances, <code>default</code> will restore
951 Apache's simple hardcoded message for configurations that would
952 otherwise inherit an existing <directive>ErrorDocument</directive>.</p>
955 ErrorDocument 404 /cgi-bin/bad_urls.pl<br /><br />
956 <Directory /web/docs><br />
958 ErrorDocument 404 default<br />
963 <p>Note that when you specify an <directive>ErrorDocument</directive>
964 that points to a remote URL (ie. anything with a method such as
965 <code>http</code> in front of it), Apache will send a redirect to the
966 client to tell it where to find the document, even if the
967 document ends up being on the same server. This has several
968 implications, the most important being that the client will not
969 receive the original error status code, but instead will
970 receive a redirect status code. This in turn can confuse web
971 robots and other clients which try to determine if a URL is
972 valid using the status code. In addition, if you use a remote
973 URL in an <code>ErrorDocument 401</code>, the client will not
974 know to prompt the user for a password since it will not
975 receive the 401 status code. Therefore, <strong>if you use an
976 <code>ErrorDocument 401</code> directive then it must refer to a local
977 document.</strong></p>
979 <p>Microsoft Internet Explorer (MSIE) will by default ignore
980 server-generated error messages when they are "too small" and substitute
981 its own "friendly" error messages. The size threshold varies depending on
982 the type of error, but in general, if you make your error document
983 greater than 512 bytes, then MSIE will show the server-generated
984 error rather than masking it. More information is available in
985 Microsoft Knowledge Base article <a
986 href="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q294807"
989 <p>Although most error messages can be overriden, there are certain
990 circumstances where the internal messages are used regardless of the
991 setting of <directive module="core">ErrorDocument</directive>. In
992 particular, if a malformed request is detected, normal request processing
993 will be immediately halted and the internal error message returned.
994 This is necessary to guard against security problems caused by
997 <p>Prior to version 2.0, messages were indicated by prefixing
998 them with a single unmatched double quote character.</p>
1001 <seealso><a href="../custom-error.html">documentation of
1002 customizable responses</a></seealso>
1003 </directivesynopsis>
1006 <name>ErrorLog</name>
1007 <description>Location where the server will log errors</description>
1008 <syntax> ErrorLog <var>file-path</var>|syslog[:<var>facility</var>]</syntax>
1009 <default>ErrorLog logs/error_log (Unix) ErrorLog logs/error.log (Windows and OS/2)</default>
1010 <contextlist><context>server config</context><context>virtual host</context>
1014 <p>The <directive>ErrorLog</directive> directive sets the name of
1015 the file to which the server will log any errors it encounters. If
1016 the <var>file-path</var> is not absolute then it is assumed to be
1017 relative to the <directive module="core">ServerRoot</directive>.</p>
1019 <example><title>Example</title>
1020 ErrorLog /var/log/httpd/error_log
1023 <p>If the <var>file-path</var>
1024 begins with a pipe (|) then it is assumed to be a command to spawn
1025 to handle the error log.</p>
1027 <example><title>Example</title>
1028 ErrorLog "|/usr/local/bin/httpd_errors"
1031 <p>Using <code>syslog</code> instead of a filename enables logging
1032 via syslogd(8) if the system supports it. The default is to use
1033 syslog facility <code>local7</code>, but you can override this by
1034 using the <code>syslog:<var>facility</var></code> syntax where
1035 <var>facility</var> can be one of the names usually documented in
1038 <example><title>Example</title>
1039 ErrorLog syslog:user
1042 <p>SECURITY: See the <a
1043 href="../misc/security_tips.html#serverroot">security tips</a>
1044 document for details on why your security could be compromised
1045 if the directory where log files are stored is writable by
1046 anyone other than the user that starts the server.</p>
1047 <note type="warning"><title>Note</title>
1048 <p>When entering a file path on non-Unix platforms, care should be taken
1049 to make sure that only forward slashed are used even though the platform
1050 may allow the use of back slashes. In general it is a good idea to always
1051 use forward slashes throughout the configuration files.</p>
1054 <seealso><directive module="core">LogLevel</directive></seealso>
1055 <seealso><a href="../logs.html">Apache Log Files</a></seealso>
1056 </directivesynopsis>
1059 <name>FileETag</name>
1060 <description>File attributes used to create the ETag
1061 HTTP response header</description>
1062 <syntax>FileETag <var>component</var> ...</syntax>
1063 <default>FileETag INode MTime Size</default>
1064 <contextlist><context>server config</context><context>virtual host</context>
1065 <context>directory</context><context>.htaccess</context>
1067 <override>FileInfo</override>
1071 The <directive>FileETag</directive> directive configures the file
1072 attributes that are used to create the <code>ETag</code> (entity
1073 tag) response header field when the document is based on a file.
1074 (The <code>ETag</code> value is used in cache management to save
1075 network bandwidth.) In Apache 1.3.22 and earlier, the
1076 <code>ETag</code> value was <em>always</em> formed
1077 from the file's inode, size, and last-modified time (mtime). The
1078 <directive>FileETag</directive> directive allows you to choose
1079 which of these -- if any -- should be used. The recognized keywords are:
1083 <dt><strong>INode</strong></dt>
1084 <dd>The file's i-node number will be included in the calculation</dd>
1085 <dt><strong>MTime</strong></dt>
1086 <dd>The date and time the file was last modified will be included</dd>
1087 <dt><strong>Size</strong></dt>
1088 <dd>The number of bytes in the file will be included</dd>
1089 <dt><strong>All</strong></dt>
1090 <dd>All available fields will be used. This is equivalent to:
1091 <example>FileETag INode MTime Size</example></dd>
1092 <dt><strong>None</strong></dt>
1093 <dd>If a document is file-based, no <code>ETag</code> field will be
1094 included in the response</dd>
1097 <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
1098 keywords may be prefixed with either <code>+</code> or <code>-</code>,
1099 which allow changes to be made to the default setting inherited
1100 from a broader scope. Any keyword appearing without such a prefix
1101 immediately and completely cancels the inherited setting.</p>
1103 <p>If a directory's configuration includes
1104 <code>FileETag INode MTime Size</code>, and a
1105 subdirectory's includes <code>FileETag -INode</code>,
1106 the setting for that subdirectory (which will be inherited by
1107 any sub-subdirectories that don't override it) will be equivalent to
1108 <code>FileETag MTime Size</code>.</p>
1110 </directivesynopsis>
1112 <directivesynopsis type="section">
1114 <description>Contains directives that apply to matched
1115 filenames</description>
1116 <syntax><Files <var>filename</var>> ... </Files></syntax>
1117 <contextlist><context>server config</context><context>virtual host</context>
1118 <context>directory</context><context>.htaccess</context>
1120 <override>All</override>
1123 <p>The <directive type="section">Files</directive> directive
1124 limits the scope of the enclosed directives by filename. It is comparable
1125 to the <directive module="core" type="section">Directory</directive>
1126 and <directive module="core" type="section">Location</directive>
1127 directives. It should be matched with a <code></Files></code>
1128 directive. The directives given within this section will be applied to
1129 any object with a basename (last component of filename) matching the
1130 specified filename. <directive type="section">Files</directive>
1131 sections are processed in the order they appear in the
1132 configuration file, after the <directive module="core"
1133 type="section">Directory</directive> sections and
1134 <code>.htaccess</code> files are read, but before <directive
1135 type="section" module="core">Location</directive> sections. Note
1136 that <directive type="section">Files</directive> can be nested
1137 inside <directive type="section"
1138 module="core">Directory</directive> sections to restrict the
1139 portion of the filesystem they apply to.</p>
1141 <p>The <var>filename</var> argument should include a filename, or
1142 a wild-card string, where <code>?</code> matches any single character,
1143 and <code>*</code> matches any sequences of characters.
1144 <glossary ref="regex">Regular expressions</glossary>
1145 can also be used, with the addition of the
1146 <code>~</code> character. For example:</p>
1149 <Files ~ "\.(gif|jpe?g|png)$">
1152 <p>would match most common Internet graphics formats. <directive
1153 module="core" type="section">FilesMatch</directive> is preferred,
1156 <p>Note that unlike <directive type="section"
1157 module="core">Directory</directive> and <directive type="section"
1158 module="core">Location</directive> sections, <directive
1159 type="section">Files</directive> sections can be used inside
1160 <code>.htaccess</code> files. This allows users to control access to
1161 their own files, at a file-by-file level.</p>
1164 <seealso><a href="../sections.html">How <Directory>, <Location>
1165 and <Files> sections work</a> for an explanation of how these
1166 different sections are combined when a request is received</seealso>
1167 </directivesynopsis>
1169 <directivesynopsis type="section">
1170 <name>FilesMatch</name>
1171 <description>Contains directives that apply to regular-expression matched
1172 filenames</description>
1173 <syntax><FilesMatch <var>regex</var>> ... </FilesMatch></syntax>
1174 <contextlist><context>server config</context><context>virtual host</context>
1175 <context>directory</context><context>.htaccess</context>
1177 <override>All</override>
1180 <p>The <directive type="section">FilesMatch</directive> directive
1181 limits the scope of the enclosed directives by filename, just as the
1182 <directive module="core" type="section">Files</directive> directive
1183 does. However, it accepts a <glossary ref="regex">regular
1184 expression</glossary>. For example:</p>
1187 <FilesMatch "\.(gif|jpe?g|png)$">
1190 <p>would match most common Internet graphics formats.</p>
1193 <seealso><a href="../sections.html">How <Directory>, <Location>
1194 and <Files> sections work</a> for an explanation of how these
1195 different sections are combined when a request is received</seealso>
1196 </directivesynopsis>
1199 <name>ForceType</name>
1200 <description>Forces all matching files to be served with the specified
1201 MIME content-type</description>
1202 <syntax>ForceType <var>MIME-type</var>|None</syntax>
1203 <contextlist><context>directory</context><context>.htaccess</context>
1205 <override>FileInfo</override>
1206 <compatibility>Moved to the core in Apache 2.0</compatibility>
1209 <p>When placed into an <code>.htaccess</code> file or a
1210 <directive type="section" module="core">Directory</directive>, or
1211 <directive type="section" module="core">Location</directive> or
1212 <directive type="section" module="core">Files</directive>
1213 section, this directive forces all matching files to be served
1214 with the content type identification given by
1215 <var>MIME-type</var>. For example, if you had a directory full of
1216 GIF files, but did not want to label them all with <code>.gif</code>,
1217 you might want to use:</p>
1223 <p>Note that unlike <directive module="core">DefaultType</directive>,
1224 this directive overrides all mime-type associations, including
1225 filename extensions, that might identify the media type.</p>
1227 <p>You can override any <directive>ForceType</directive> setting
1228 by using the value of <code>None</code>:</p>
1231 # force all files to be image/gif:<br />
1232 <Location /images><br />
1234 ForceType image/gif<br />
1236 </Location><br />
1238 # but normal mime-type associations here:<br />
1239 <Location /images/mixed><br />
1241 ForceType None<br />
1246 </directivesynopsis>
1249 <name>HostnameLookups</name>
1250 <description>Enables DNS lookups on client IP addresses</description>
1251 <syntax>HostnameLookups On|Off|Double</syntax>
1252 <default>HostnameLookups Off</default>
1253 <contextlist><context>server config</context><context>virtual host</context>
1254 <context>directory</context></contextlist>
1257 <p>This directive enables DNS lookups so that host names can be
1258 logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
1259 The value <code>Double</code> refers to doing double-reverse
1260 DNS lookup. That is, after a reverse lookup is performed, a forward
1261 lookup is then performed on that result. At least one of the IP
1262 addresses in the forward lookup must match the original
1263 address. (In "tcpwrappers" terminology this is called
1264 <code>PARANOID</code>.)</p>
1266 <p>Regardless of the setting, when <module>mod_authz_host</module> is
1267 used for controlling access by hostname, a double reverse lookup
1268 will be performed. This is necessary for security. Note that the
1269 result of this double-reverse isn't generally available unless you
1270 set <code>HostnameLookups Double</code>. For example, if only
1271 <code>HostnameLookups On</code> and a request is made to an object
1272 that is protected by hostname restrictions, regardless of whether
1273 the double-reverse fails or not, CGIs will still be passed the
1274 single-reverse result in <code>REMOTE_HOST</code>.</p>
1276 <p>The default is <code>Off</code> in order to save the network
1277 traffic for those sites that don't truly need the reverse
1278 lookups done. It is also better for the end users because they
1279 don't have to suffer the extra latency that a lookup entails.
1280 Heavily loaded sites should leave this directive
1281 <code>Off</code>, since DNS lookups can take considerable
1282 amounts of time. The utility <program>logresolve</program>, compiled by
1283 default to the <code>bin</code> subdirectory of your installation
1284 directory, can be used to look up host names from logged IP addresses
1287 </directivesynopsis>
1289 <directivesynopsis type="section">
1290 <name>IfDefine</name>
1291 <description>Encloses directives that will be processed only
1292 if a test is true at startup</description>
1293 <syntax><IfDefine [!]<var>parameter-name</var>> ...
1294 </IfDefine></syntax>
1295 <contextlist><context>server config</context><context>virtual host</context>
1296 <context>directory</context><context>.htaccess</context>
1298 <override>All</override>
1301 <p>The <code><IfDefine <var>test</var>>...</IfDefine>
1302 </code> section is used to mark directives that are conditional. The
1303 directives within an <directive type="section">IfDefine</directive>
1304 section are only processed if the <var>test</var> is true. If <var>
1305 test</var> is false, everything between the start and end markers is
1308 <p>The <var>test</var> in the <directive type="section"
1309 >IfDefine</directive> section directive can be one of two forms:</p>
1312 <li><var>parameter-name</var></li>
1314 <li><code>!</code><var>parameter-name</var></li>
1317 <p>In the former case, the directives between the start and end
1318 markers are only processed if the parameter named
1319 <var>parameter-name</var> is defined. The second format reverses
1320 the test, and only processes the directives if
1321 <var>parameter-name</var> is <strong>not</strong> defined.</p>
1323 <p>The <var>parameter-name</var> argument is a define as given on the
1324 <program>httpd</program> command line via <code>-D<var>parameter</var>
1325 </code> at the time the server was started or by the <directive
1326 module="core">Define</directive> directive.</p>
1328 <p><directive type="section">IfDefine</directive> sections are
1329 nest-able, which can be used to implement simple
1330 multiple-parameter tests. Example:</p>
1333 httpd -DReverseProxy ...<br />
1336 <IfDefine ReverseProxy><br />
1338 LoadModule rewrite_module modules/mod_rewrite.so<br />
1339 LoadModule proxy_module modules/libproxy.so<br />
1344 </directivesynopsis>
1346 <directivesynopsis type="section">
1347 <name>IfModule</name>
1348 <description>Encloses directives that are processed conditional on the
1349 presence or absence of a specific module</description>
1350 <syntax><IfModule [!]<var>module-file</var>|<var>module-identifier</var>> ...
1351 </IfModule></syntax>
1352 <contextlist><context>server config</context><context>virtual host</context>
1353 <context>directory</context><context>.htaccess</context>
1355 <override>All</override>
1356 <compatibility>Module identifiers are available in version 2.1 and
1357 later.</compatibility>
1360 <p>The <code><IfModule <var>test</var>>...</IfModule></code>
1361 section is used to mark directives that are conditional on the presence of
1362 a specific module. The directives within an <directive type="section"
1363 >IfModule</directive> section are only processed if the <var>test</var>
1364 is true. If <var>test</var> is false, everything between the start and
1365 end markers is ignored.</p>
1367 <p>The <var>test</var> in the <directive type="section"
1368 >IfModule</directive> section directive can be one of two forms:</p>
1371 <li><var>module</var></li>
1373 <li>!<var>module</var></li>
1376 <p>In the former case, the directives between the start and end
1377 markers are only processed if the module named <var>module</var>
1378 is included in Apache -- either compiled in or
1379 dynamically loaded using <directive module="mod_so"
1380 >LoadModule</directive>. The second format reverses the test,
1381 and only processes the directives if <var>module</var> is
1382 <strong>not</strong> included.</p>
1384 <p>The <var>module</var> argument can be either the module identifier or
1385 the file name of the module, at the time it was compiled. For example,
1386 <code>rewrite_module</code> is the identifier and
1387 <code>mod_rewrite.c</code> is the file name. If a module consists of
1388 several source files, use the name of the file containing the string
1389 <code>STANDARD20_MODULE_STUFF</code>.</p>
1391 <p><directive type="section">IfModule</directive> sections are
1392 nest-able, which can be used to implement simple multiple-module
1395 <note>This section should only be used if you need to have one
1396 configuration file that works whether or not a specific module
1397 is available. In normal operation, directives need not be
1398 placed in <directive type="section">IfModule</directive>
1401 </directivesynopsis>
1404 <name>Include</name>
1405 <description>Includes other configuration files from within
1406 the server configuration files</description>
1407 <syntax>Include <var>file-path</var>|<var>directory-path</var></syntax>
1408 <contextlist><context>server config</context><context>virtual host</context>
1409 <context>directory</context>
1411 <compatibility>Wildcard matching available in 2.0.41 and later</compatibility>
1414 <p>This directive allows inclusion of other configuration files
1415 from within the server configuration files.</p>
1417 <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used to
1418 include several files at once, in alphabetical order. In
1419 addition, if <directive>Include</directive> points to a directory,
1420 rather than a file, Apache will read all files in that directory
1421 and any subdirectory. But including entire directories is not
1422 recommended, because it is easy to accidentally leave temporary
1423 files in a directory that can cause <program>httpd</program> to
1426 <p>The file path specified may be an absolute path, or may be relative
1427 to the <directive module="core">ServerRoot</directive> directory.</p>
1432 Include /usr/local/apache2/conf/ssl.conf<br />
1433 Include /usr/local/apache2/conf/vhosts/*.conf
1436 <p>Or, providing paths relative to your <directive
1437 module="core">ServerRoot</directive> directory:</p>
1440 Include conf/ssl.conf<br />
1441 Include conf/vhosts/*.conf
1444 <p>Running <code>apachectl configtest</code> will give you a list
1445 of the files that are being processed during the configuration
1449 root@host# apachectl configtest<br />
1450 Processing config file: /usr/local/apache2/conf/ssl.conf<br />
1451 Processing config file: /usr/local/apache2/conf/vhosts/vhost1.conf<br />
1452 Processing config file: /usr/local/apache2/conf/vhosts/vhost2.conf<br />
1457 <seealso><program>apachectl</program></seealso>
1458 </directivesynopsis>
1461 <name>KeepAlive</name>
1462 <description>Enables HTTP persistent connections</description>
1463 <syntax>KeepAlive On|Off</syntax>
1464 <default>KeepAlive On</default>
1465 <contextlist><context>server config</context><context>virtual host</context>
1469 <p>The Keep-Alive extension to HTTP/1.0 and the persistent
1470 connection feature of HTTP/1.1 provide long-lived HTTP sessions
1471 which allow multiple requests to be sent over the same TCP
1472 connection. In some cases this has been shown to result in an
1473 almost 50% speedup in latency times for HTML documents with
1474 many images. To enable Keep-Alive connections, set
1475 <code>KeepAlive On</code>.</p>
1477 <p>For HTTP/1.0 clients, Keep-Alive connections will only be
1478 used if they are specifically requested by a client. In
1479 addition, a Keep-Alive connection with an HTTP/1.0 client can
1480 only be used when the length of the content is known in
1481 advance. This implies that dynamic content such as CGI output,
1482 SSI pages, and server-generated directory listings will
1483 generally not use Keep-Alive connections to HTTP/1.0 clients.
1484 For HTTP/1.1 clients, persistent connections are the default
1485 unless otherwise specified. If the client requests it, chunked
1486 encoding will be used in order to send content of unknown
1487 length over persistent connections.</p>
1489 <p>When a client uses a Keep-Alive connection it will be counted
1490 as a single "request" for the MaxRequestsPerChild directive, regardless
1491 of how many requests are sent using the connection.</p>
1494 <seealso><directive module="core">MaxKeepAliveRequests</directive></seealso>
1495 </directivesynopsis>
1498 <name>KeepAliveTimeout</name>
1499 <description>Amount of time the server will wait for subsequent
1500 requests on a persistent connection</description>
1501 <syntax>KeepAliveTimeout <var>seconds</var></syntax>
1502 <default>KeepAliveTimeout 5</default>
1503 <contextlist><context>server config</context><context>virtual host</context>
1507 <p>The number of seconds Apache will wait for a subsequent
1508 request before closing the connection. Once a request has been
1509 received, the timeout value specified by the
1510 <directive module="core">Timeout</directive> directive applies.</p>
1512 <p>Setting <directive>KeepAliveTimeout</directive> to a high value
1513 may cause performance problems in heavily loaded servers. The
1514 higher the timeout, the more server processes will be kept
1515 occupied waiting on connections with idle clients.</p>
1517 </directivesynopsis>
1519 <directivesynopsis type="section">
1521 <description>Restrict enclosed access controls to only certain HTTP
1522 methods</description>
1523 <syntax><Limit <var>method</var> [<var>method</var>] ... > ...
1524 </Limit></syntax>
1525 <contextlist><context>server config</context><context>virtual host</context>
1526 <context>directory</context><context>.htaccess</context>
1528 <override>All</override>
1531 <p>Access controls are normally effective for
1532 <strong>all</strong> access methods, and this is the usual
1533 desired behavior. <strong>In the general case, access control
1534 directives should not be placed within a
1535 <directive type="section">Limit</directive> section.</strong></p>
1537 <p>The purpose of the <directive type="section">Limit</directive>
1538 directive is to restrict the effect of the access controls to the
1539 nominated HTTP methods. For all other methods, the access
1540 restrictions that are enclosed in the <directive
1541 type="section">Limit</directive> bracket <strong>will have no
1542 effect</strong>. The following example applies the access control
1543 only to the methods <code>POST</code>, <code>PUT</code>, and
1544 <code>DELETE</code>, leaving all other methods unprotected:</p>
1547 <Limit POST PUT DELETE><br />
1549 Require valid-user<br />
1554 <p>The method names listed can be one or more of: <code>GET</code>,
1555 <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
1556 <code>CONNECT</code>, <code>OPTIONS</code>,
1557 <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
1558 <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
1559 <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
1560 case-sensitive.</strong> If <code>GET</code> is used it will also
1561 restrict <code>HEAD</code> requests. The <code>TRACE</code> method
1562 cannot be limited.</p>
1564 <note type="warning">A <directive type="section"
1565 module="core">LimitExcept</directive> section should always be
1566 used in preference to a <directive type="section"
1567 module="core">Limit</directive> section when restricting access,
1568 since a <directive type="section"
1569 module="core">LimitExcept</directive> section provides protection
1570 against arbitrary methods.</note>
1573 </directivesynopsis>
1575 <directivesynopsis type="section">
1576 <name>LimitExcept</name>
1577 <description>Restrict access controls to all HTTP methods
1578 except the named ones</description>
1579 <syntax><LimitExcept <var>method</var> [<var>method</var>] ... > ...
1580 </LimitExcept></syntax>
1581 <contextlist><context>server config</context><context>virtual host</context>
1582 <context>directory</context><context>.htaccess</context>
1584 <override>All</override>
1587 <p><directive type="section">LimitExcept</directive> and
1588 <code></LimitExcept></code> are used to enclose
1589 a group of access control directives which will then apply to any
1590 HTTP access method <strong>not</strong> listed in the arguments;
1591 i.e., it is the opposite of a <directive type="section"
1592 module="core">Limit</directive> section and can be used to control
1593 both standard and nonstandard/unrecognized methods. See the
1594 documentation for <directive module="core"
1595 type="section">Limit</directive> for more details.</p>
1600 <LimitExcept POST GET><br />
1602 Require valid-user<br />
1604 </LimitExcept>
1608 </directivesynopsis>
1611 <name>LimitInternalRecursion</name>
1612 <description>Determine maximum number of internal redirects and nested
1613 subrequests</description>
1614 <syntax>LimitInternalRecursion <var>number</var> [<var>number</var>]</syntax>
1615 <default>LimitInternalRecursion 10</default>
1616 <contextlist><context>server config</context><context>virtual host</context>
1618 <compatibility>Available in Apache 2.0.47 and later</compatibility>
1621 <p>An internal redirect happens, for example, when using the <directive
1622 module="mod_actions">Action</directive> directive, which internally
1623 redirects the original request to a CGI script. A subrequest is Apache's
1624 mechanism to find out what would happen for some URI if it were requested.
1625 For example, <module>mod_dir</module> uses subrequests to look for the
1626 files listed in the <directive module="mod_dir">DirectoryIndex</directive>
1629 <p><directive>LimitInternalRecursion</directive> prevents the server
1630 from crashing when entering an infinite loop of internal redirects or
1631 subrequests. Such loops are usually caused by misconfigurations.</p>
1633 <p>The directive stores two different limits, which are evaluated on
1634 per-request basis. The first <var>number</var> is the maximum number of
1635 internal redirects, that may follow each other. The second <var>number</var>
1636 determines, how deep subrequests may be nested. If you specify only one
1637 <var>number</var>, it will be assigned to both limits.</p>
1639 <example><title>Example</title>
1640 LimitInternalRecursion 5
1643 </directivesynopsis>
1646 <name>LimitRequestBody</name>
1647 <description>Restricts the total size of the HTTP request body sent
1648 from the client</description>
1649 <syntax>LimitRequestBody <var>bytes</var></syntax>
1650 <default>LimitRequestBody 0</default>
1651 <contextlist><context>server config</context><context>virtual host</context>
1652 <context>directory</context><context>.htaccess</context>
1654 <override>All</override>
1657 <p>This directive specifies the number of <var>bytes</var> from 0
1658 (meaning unlimited) to 2147483647 (2GB) that are allowed in a
1661 <p>The <directive>LimitRequestBody</directive> directive allows
1662 the user to set a limit on the allowed size of an HTTP request
1663 message body within the context in which the directive is given
1664 (server, per-directory, per-file or per-location). If the client
1665 request exceeds that limit, the server will return an error
1666 response instead of servicing the request. The size of a normal
1667 request message body will vary greatly depending on the nature of
1668 the resource and the methods allowed on that resource. CGI scripts
1669 typically use the message body for retrieving form information.
1670 Implementations of the <code>PUT</code> method will require
1671 a value at least as large as any representation that the server
1672 wishes to accept for that resource.</p>
1674 <p>This directive gives the server administrator greater
1675 control over abnormal client request behavior, which may be
1676 useful for avoiding some forms of denial-of-service
1679 <p>If, for example, you are permitting file upload to a particular
1680 location, and wish to limit the size of the uploaded file to 100K,
1681 you might use the following directive:</p>
1684 LimitRequestBody 102400
1688 </directivesynopsis>
1691 <name>LimitRequestFields</name>
1692 <description>Limits the number of HTTP request header fields that
1693 will be accepted from the client</description>
1694 <syntax>LimitRequestFields <var>number</var></syntax>
1695 <default>LimitRequestFields 100</default>
1696 <contextlist><context>server config</context></contextlist>
1699 <p><var>Number</var> is an integer from 0 (meaning unlimited) to
1700 32767. The default value is defined by the compile-time
1701 constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
1704 <p>The <directive>LimitRequestFields</directive> directive allows
1705 the server administrator to modify the limit on the number of
1706 request header fields allowed in an HTTP request. A server needs
1707 this value to be larger than the number of fields that a normal
1708 client request might include. The number of request header fields
1709 used by a client rarely exceeds 20, but this may vary among
1710 different client implementations, often depending upon the extent
1711 to which a user has configured their browser to support detailed
1712 content negotiation. Optional HTTP extensions are often expressed
1713 using request header fields.</p>
1715 <p>This directive gives the server administrator greater
1716 control over abnormal client request behavior, which may be
1717 useful for avoiding some forms of denial-of-service attacks.
1718 The value should be increased if normal clients see an error
1719 response from the server that indicates too many fields were
1720 sent in the request.</p>
1725 LimitRequestFields 50
1729 </directivesynopsis>
1732 <name>LimitRequestFieldSize</name>
1733 <description>Limits the size of the HTTP request header allowed from the
1734 client</description>
1735 <syntax>LimitRequestFieldSize <var>bytes</var></syntax>
1736 <default>LimitRequestFieldSize 8190</default>
1737 <contextlist><context>server config</context></contextlist>
1740 <p>This directive specifies the number of <var>bytes</var>
1741 that will be allowed in an HTTP request header.</p>
1743 <p>The <directive>LimitRequestFieldSize</directive> directive
1744 allows the server administrator to reduce or increase the limit
1745 on the allowed size of an HTTP request header field. A server
1746 needs this value to be large enough to hold any one header field
1747 from a normal client request. The size of a normal request header
1748 field will vary greatly among different client implementations,
1749 often depending upon the extent to which a user has configured
1750 their browser to support detailed content negotiation. SPNEGO
1751 authentication headers can be up to 12392 bytes.</p>
1753 <p>This directive gives the server administrator greater
1754 control over abnormal client request behavior, which may be
1755 useful for avoiding some forms of denial-of-service attacks.</p>
1760 LimitRequestFieldSize 4094
1763 <note>Under normal conditions, the value should not be changed from
1767 </directivesynopsis>
1770 <name>LimitRequestLine</name>
1771 <description>Limit the size of the HTTP request line that will be accepted
1772 from the client</description>
1773 <syntax>LimitRequestLine <var>bytes</var></syntax>
1774 <default>LimitRequestLine 8190</default>
1775 <contextlist><context>server config</context></contextlist>
1778 <p>This directive sets the number of <var>bytes</var> that will be
1779 allowed on the HTTP request-line.</p>
1781 <p>The <directive>LimitRequestLine</directive> directive allows
1782 the server administrator to reduce or increase the limit on the allowed size
1783 of a client's HTTP request-line. Since the request-line consists of the
1784 HTTP method, URI, and protocol version, the
1785 <directive>LimitRequestLine</directive> directive places a
1786 restriction on the length of a request-URI allowed for a request
1787 on the server. A server needs this value to be large enough to
1788 hold any of its resource names, including any information that
1789 might be passed in the query part of a <code>GET</code> request.</p>
1791 <p>This directive gives the server administrator greater
1792 control over abnormal client request behavior, which may be
1793 useful for avoiding some forms of denial-of-service attacks.</p>
1798 LimitRequestLine 4094
1801 <note>Under normal conditions, the value should not be changed from
1804 </directivesynopsis>
1807 <name>LimitXMLRequestBody</name>
1808 <description>Limits the size of an XML-based request body</description>
1809 <syntax>LimitXMLRequestBody <var>bytes</var></syntax>
1810 <default>LimitXMLRequestBody 1000000</default>
1811 <contextlist><context>server config</context><context>virtual host</context>
1812 <context>directory</context><context>.htaccess</context></contextlist>
1813 <override>All</override>
1816 <p>Limit (in bytes) on maximum size of an XML-based request
1817 body. A value of <code>0</code> will disable any checking.</p>
1822 LimitXMLRequestBody 0
1826 </directivesynopsis>
1828 <directivesynopsis type="section">
1829 <name>Location</name>
1830 <description>Applies the enclosed directives only to matching
1832 <syntax><Location
1833 <var>URL-path</var>|<var>URL</var>> ... </Location></syntax>
1834 <contextlist><context>server config</context><context>virtual host</context>
1838 <p>The <directive type="section">Location</directive> directive
1839 limits the scope of the enclosed directives by URL. It is similar to the
1840 <directive type="section" module="core">Directory</directive>
1841 directive, and starts a subsection which is terminated with a
1842 <code></Location></code> directive. <directive
1843 type="section">Location</directive> sections are processed in the
1844 order they appear in the configuration file, after the <directive
1845 type="section" module="core">Directory</directive> sections and
1846 <code>.htaccess</code> files are read, and after the <directive
1847 type="section" module="core">Files</directive> sections.</p>
1849 <p><directive type="section">Location</directive> sections operate
1850 completely outside the filesystem. This has several consequences.
1851 Most importantly, <directive type="section">Location</directive>
1852 directives should not be used to control access to filesystem
1853 locations. Since several different URLs may map to the same
1854 filesystem location, such access controls may by circumvented.</p>
1856 <note><title>When to use <directive
1857 type="section">Location</directive></title>
1859 <p>Use <directive type="section">Location</directive> to apply
1860 directives to content that lives outside the filesystem. For
1861 content that lives in the filesystem, use <directive
1862 type="section" module="core">Directory</directive> and <directive
1863 type="section" module="core">Files</directive>. An exception is
1864 <code><Location /></code>, which is an easy way to
1865 apply a configuration to the entire server.</p>
1868 <p>For all origin (non-proxy) requests, the URL to be matched is a
1869 URL-path of the form <code>/path/</code>. No scheme, hostname,
1870 port, or query string may be included. For proxy requests, the
1871 URL to be matched is of the form
1872 <code>scheme://servername/path</code>, and you must include the
1875 <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
1876 any single character, and <code>*</code> matches any sequences of
1877 characters. Neither wildcard character matches a / in the URL-path.</p>
1879 <p><glossary ref="regex">Regular expressions</glossary>
1880 can also be used, with the addition of the
1881 <code>~</code> character. For example:</p>
1884 <Location ~ "/(extra|special)/data">
1887 <p>would match URLs that contained the substring <code>/extra/data</code>
1888 or <code>/special/data</code>. The directive <directive
1889 type="section" module="core">LocationMatch</directive> behaves
1890 identical to the regex version of <directive
1891 type="section">Location</directive>.</p>
1893 <p>The <directive type="section">Location</directive>
1894 functionality is especially useful when combined with the
1895 <directive module="core">SetHandler</directive>
1896 directive. For example, to enable status requests, but allow them
1897 only from browsers at <code>foo.com</code>, you might use:</p>
1900 <Location /status><br />
1902 SetHandler server-status<br />
1903 Order Deny,Allow<br />
1905 Allow from .foo.com<br />
1910 <note><title>Note about / (slash)</title>
1911 <p>The slash character has special meaning depending on where in a
1912 URL it appears. People may be used to its behavior in the filesystem
1913 where multiple adjacent slashes are frequently collapsed to a single
1914 slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
1915 <code>/home/foo</code>). In URL-space this is not necessarily true.
1916 The <directive type="section" module="core">LocationMatch</directive>
1917 directive and the regex version of <directive type="section"
1918 >Location</directive> require you to explicitly specify multiple
1919 slashes if that is your intention.</p>
1921 <p>For example, <code><LocationMatch ^/abc></code> would match
1922 the request URL <code>/abc</code> but not the request URL <code>
1923 //abc</code>. The (non-regex) <directive type="section"
1924 >Location</directive> directive behaves similarly when used for
1925 proxy requests. But when (non-regex) <directive type="section"
1926 >Location</directive> is used for non-proxy requests it will
1927 implicitly match multiple slashes with a single slash. For example,
1928 if you specify <code><Location /abc/def></code> and the
1929 request is to <code>/abc//def</code> then it will match.</p>
1932 <seealso><a href="../sections.html">How <Directory>, <Location>
1933 and <Files> sections work</a> for an explanation of how these
1934 different sections are combined when a request is received</seealso>
1935 </directivesynopsis>
1937 <directivesynopsis type="section">
1938 <name>LocationMatch</name>
1939 <description>Applies the enclosed directives only to regular-expression
1940 matching URLs</description>
1941 <syntax><LocationMatch
1942 <var>regex</var>> ... </LocationMatch></syntax>
1943 <contextlist><context>server config</context><context>virtual host</context>
1947 <p>The <directive type="section">LocationMatch</directive> directive
1948 limits the scope of the enclosed directives by URL, in an identical manner
1949 to <directive module="core" type="section">Location</directive>. However,
1950 it takes a <glossary ref="regex">regular expression</glossary>
1951 as an argument instead of a simple string. For example:</p>
1954 <LocationMatch "/(extra|special)/data">
1957 <p>would match URLs that contained the substring <code>/extra/data</code>
1958 or <code>/special/data</code>.</p>
1961 <seealso><a href="../sections.html">How <Directory>, <Location>
1962 and <Files> sections work</a> for an explanation of how these
1963 different sections are combined when a request is received</seealso>
1964 </directivesynopsis>
1967 <name>LogLevel</name>
1968 <description>Controls the verbosity of the ErrorLog</description>
1969 <syntax>LogLevel <var>level</var></syntax>
1970 <default>LogLevel warn</default>
1971 <contextlist><context>server config</context><context>virtual host</context>
1975 <p><directive>LogLevel</directive> adjusts the verbosity of the
1976 messages recorded in the error logs (see <directive
1977 module="core">ErrorLog</directive> directive). The following
1978 <var>level</var>s are available, in order of decreasing
1982 <columnspec><column width=".2"/><column width=".3"/><column width=".5"/>
1985 <th><strong>Level</strong> </th>
1987 <th><strong>Description</strong> </th>
1989 <th><strong>Example</strong> </th>
1993 <td><code>emerg</code> </td>
1995 <td>Emergencies - system is unusable.</td>
1997 <td>"Child cannot open lock file. Exiting"</td>
2001 <td><code>alert</code> </td>
2003 <td>Action must be taken immediately.</td>
2005 <td>"getpwuid: couldn't determine user name from uid"</td>
2009 <td><code>crit</code> </td>
2011 <td>Critical Conditions.</td>
2013 <td>"socket: Failed to get a socket, exiting child"</td>
2017 <td><code>error</code> </td>
2019 <td>Error conditions.</td>
2021 <td>"Premature end of script headers"</td>
2025 <td><code>warn</code> </td>
2027 <td>Warning conditions.</td>
2029 <td>"child process 1234 did not exit, sending another
2034 <td><code>notice</code> </td>
2036 <td>Normal but significant condition.</td>
2038 <td>"httpd: caught SIGBUS, attempting to dump core in
2043 <td><code>info</code> </td>
2045 <td>Informational.</td>
2047 <td>"Server seems busy, (you may need to increase
2048 StartServers, or Min/MaxSpareServers)..."</td>
2052 <td><code>debug</code> </td>
2054 <td>Debug-level messages</td>
2056 <td>"Opening config file ..."</td>
2060 <p>When a particular level is specified, messages from all
2061 other levels of higher significance will be reported as well.
2062 <em>E.g.</em>, when <code>LogLevel info</code> is specified,
2063 then messages with log levels of <code>notice</code> and
2064 <code>warn</code> will also be posted.</p>
2066 <p>Using a level of at least <code>crit</code> is
2075 <note><title>Note</title>
2076 <p>When logging to a regular file messages of the level
2077 <code>notice</code> cannot be suppressed and thus are always
2078 logged. However, this doesn't apply when logging is done
2079 using <code>syslog</code>.</p>
2082 </directivesynopsis>
2085 <name>MaxKeepAliveRequests</name>
2086 <description>Number of requests allowed on a persistent
2087 connection</description>
2088 <syntax>MaxKeepAliveRequests <var>number</var></syntax>
2089 <default>MaxKeepAliveRequests 100</default>
2090 <contextlist><context>server config</context><context>virtual host</context>
2094 <p>The <directive>MaxKeepAliveRequests</directive> directive
2095 limits the number of requests allowed per connection when
2096 <directive module="core" >KeepAlive</directive> is on. If it is
2097 set to <code>0</code>, unlimited requests will be allowed. We
2098 recommend that this setting be kept to a high value for maximum
2099 server performance.</p>
2104 MaxKeepAliveRequests 500
2107 </directivesynopsis>
2110 <name>NameVirtualHost</name>
2111 <description>Designates an IP address for name-virtual
2112 hosting</description>
2113 <syntax>NameVirtualHost <var>addr</var>[:<var>port</var>]</syntax>
2114 <contextlist><context>server config</context></contextlist>
2117 <p>The <directive>NameVirtualHost</directive> directive is a
2118 required directive if you want to configure <a
2119 href="../vhosts/">name-based virtual hosts</a>.</p>
2121 <p>Although <var>addr</var> can be hostname it is recommended
2122 that you always use an IP address, e.g.</p>
2125 NameVirtualHost 111.22.33.44
2128 <p>With the <directive>NameVirtualHost</directive> directive you
2129 specify the IP address on which the server will receive requests
2130 for the name-based virtual hosts. This will usually be the address
2131 to which your name-based virtual host names resolve. In cases
2132 where a firewall or other proxy receives the requests and forwards
2133 them on a different IP address to the server, you must specify the
2134 IP address of the physical interface on the machine which will be
2135 servicing the requests. If you have multiple name-based hosts on
2136 multiple addresses, repeat the directive for each address.</p>
2138 <note><title>Note</title>
2139 <p>Note, that the "main server" and any <code>_default_</code> servers
2140 will <strong>never</strong> be served for a request to a
2141 <directive>NameVirtualHost</directive> IP address (unless for some
2142 reason you specify <directive>NameVirtualHost</directive> but then
2143 don't define any <directive>VirtualHost</directive>s for that
2147 <p>Optionally you can specify a port number on which the
2148 name-based virtual hosts should be used, e.g.</p>
2151 NameVirtualHost 111.22.33.44:8080
2154 <p>IPv6 addresses must be enclosed in square brackets, as shown
2155 in the following example:</p>
2158 NameVirtualHost [2001:db8::a00:20ff:fea7:ccea]:8080
2161 <p>To receive requests on all interfaces, you can use an argument of
2168 <note><title>Argument to <directive type="section">VirtualHost</directive>
2170 <p>Note that the argument to the <directive
2171 type="section">VirtualHost</directive> directive must
2172 exactly match the argument to the <directive
2173 >NameVirtualHost</directive> directive.</p>
2176 NameVirtualHost 1.2.3.4<br />
2177 <VirtualHost 1.2.3.4><br />
2179 </VirtualHost><br />
2184 <seealso><a href="../vhosts/">Virtual Hosts
2185 documentation</a></seealso>
2187 </directivesynopsis>
2190 <name>Options</name>
2191 <description>Configures what features are available in a particular
2192 directory</description>
2194 [+|-]<var>option</var> [[+|-]<var>option</var>] ...</syntax>
2195 <default>Options All</default>
2196 <contextlist><context>server config</context><context>virtual host</context>
2197 <context>directory</context><context>.htaccess</context>
2199 <override>Options</override>
2202 <p>The <directive>Options</directive> directive controls which
2203 server features are available in a particular directory.</p>
2205 <p><var>option</var> can be set to <code>None</code>, in which
2206 case none of the extra features are enabled, or one or more of
2210 <dt><code>All</code></dt>
2212 <dd>All options except for <code>MultiViews</code>. This is the default
2215 <dt><code>ExecCGI</code></dt>
2218 Execution of CGI scripts using <module>mod_cgi</module>
2221 <dt><code>FollowSymLinks</code></dt>
2225 The server will follow symbolic links in this directory.
2227 <p>Even though the server follows the symlink it does <em>not</em>
2228 change the pathname used to match against <directive type="section"
2229 module="core">Directory</directive> sections.</p>
2230 <p>Note also, that this option <strong>gets ignored</strong> if set
2231 inside a <directive type="section" module="core">Location</directive>
2233 <p>Omitting this option should not be considered a security restriction,
2234 since symlink testing is subject to race conditions that make it
2238 <dt><code>Includes</code></dt>
2241 Server-side includes provided by <module>mod_include</module>
2244 <dt><code>IncludesNOEXEC</code></dt>
2248 Server-side includes are permitted, but the <code>#exec
2249 cmd</code> and <code>#exec cgi</code> are disabled. It is still
2250 possible to <code>#include virtual</code> CGI scripts from
2251 <directive module="mod_alias">ScriptAlias</directive>ed
2254 <dt><code>Indexes</code></dt>
2257 If a URL which maps to a directory is requested, and there
2258 is no <directive module="mod_dir">DirectoryIndex</directive>
2259 (<em>e.g.</em>, <code>index.html</code>) in that directory, then
2260 <module>mod_autoindex</module> will return a formatted listing
2261 of the directory.</dd>
2263 <dt><code>MultiViews</code></dt>
2266 <a href="../content-negotiation.html">Content negotiated</a>
2267 "MultiViews" are allowed using
2268 <module>mod_negotiation</module>.</dd>
2270 <dt><code>SymLinksIfOwnerMatch</code></dt>
2272 <dd>The server will only follow symbolic links for which the
2273 target file or directory is owned by the same user id as the
2276 <note><title>Note</title> <p>This option gets ignored if
2277 set inside a <directive module="core"
2278 type="section">Location</directive> section.</p>
2279 <p>This option should not be considered a security restriction,
2280 since symlink testing is subject to race conditions that make it
2281 circumventable.</p></note>
2285 <p>Normally, if multiple <directive>Options</directive> could
2286 apply to a directory, then the most specific one is used and
2287 others are ignored; the options are not merged. (See <a
2288 href="../sections.html#mergin">how sections are merged</a>.)
2289 However if <em>all</em> the options on the
2290 <directive>Options</directive> directive are preceded by a
2291 <code>+</code> or <code>-</code> symbol, the options are
2292 merged. Any options preceded by a <code>+</code> are added to the
2293 options currently in force, and any options preceded by a
2294 <code>-</code> are removed from the options currently in
2297 <note type="warning"><title>Warning</title>
2298 <p>Mixing <directive>Options</directive> with a <code>+</code> or
2299 <code>-</code> with those without is not valid syntax, and is likely
2300 to cause unexpected results.</p>
2303 <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>
2306 <Directory /web/docs><br />
2308 Options Indexes FollowSymLinks<br />
2310 </Directory><br />
2312 <Directory /web/docs/spec><br />
2314 Options Includes<br />
2319 <p>then only <code>Includes</code> will be set for the
2320 <code>/web/docs/spec</code> directory. However if the second
2321 <directive>Options</directive> directive uses the <code>+</code> and
2322 <code>-</code> symbols:</p>
2325 <Directory /web/docs><br />
2327 Options Indexes FollowSymLinks<br />
2329 </Directory><br />
2331 <Directory /web/docs/spec><br />
2333 Options +Includes -Indexes<br />
2338 <p>then the options <code>FollowSymLinks</code> and
2339 <code>Includes</code> are set for the <code>/web/docs/spec</code>
2342 <note><title>Note</title>
2343 <p>Using <code>-IncludesNOEXEC</code> or
2344 <code>-Includes</code> disables server-side includes completely
2345 regardless of the previous setting.</p>
2348 <p>The default in the absence of any other settings is
2349 <code>All</code>.</p>
2351 </directivesynopsis>
2354 <name>RLimitCPU</name>
2355 <description>Limits the CPU consumption of processes launched
2356 by Apache children</description>
2357 <syntax>RLimitCPU <var>seconds</var>|max [<var>seconds</var>|max]</syntax>
2358 <default>Unset; uses operating system defaults</default>
2359 <contextlist><context>server config</context><context>virtual host</context>
2360 <context>directory</context><context>.htaccess</context></contextlist>
2361 <override>All</override>
2364 <p>Takes 1 or 2 parameters. The first parameter sets the soft
2365 resource limit for all processes and the second parameter sets
2366 the maximum resource limit. Either parameter can be a number,
2367 or <code>max</code> to indicate to the server that the limit should
2368 be set to the maximum allowed by the operating system
2369 configuration. Raising the maximum resource limit requires that
2370 the server is running as <code>root</code>, or in the initial startup
2373 <p>This applies to processes forked off from Apache children
2374 servicing requests, not the Apache children themselves. This
2375 includes CGI scripts and SSI exec commands, but not any
2376 processes forked off from the Apache parent such as piped
2379 <p>CPU resource limits are expressed in seconds per
2382 <seealso><directive module="core">RLimitMEM</directive></seealso>
2383 <seealso><directive module="core">RLimitNPROC</directive></seealso>
2384 </directivesynopsis>
2387 <name>RLimitMEM</name>
2388 <description>Limits the memory consumption of processes launched
2389 by Apache children</description>
2390 <syntax>RLimitMEM <var>bytes</var>|max [<var>bytes</var>|max]</syntax>
2391 <default>Unset; uses operating system defaults</default>
2392 <contextlist><context>server config</context><context>virtual host</context>
2393 <context>directory</context><context>.htaccess</context></contextlist>
2394 <override>All</override>
2397 <p>Takes 1 or 2 parameters. The first parameter sets the soft
2398 resource limit for all processes and the second parameter sets
2399 the maximum resource limit. Either parameter can be a number,
2400 or <code>max</code> to indicate to the server that the limit should
2401 be set to the maximum allowed by the operating system
2402 configuration. Raising the maximum resource limit requires that
2403 the server is running as <code>root</code>, or in the initial startup
2406 <p>This applies to processes forked off from Apache children
2407 servicing requests, not the Apache children themselves. This
2408 includes CGI scripts and SSI exec commands, but not any
2409 processes forked off from the Apache parent such as piped
2412 <p>Memory resource limits are expressed in bytes per
2415 <seealso><directive module="core">RLimitCPU</directive></seealso>
2416 <seealso><directive module="core">RLimitNPROC</directive></seealso>
2417 </directivesynopsis>
2420 <name>RLimitNPROC</name>
2421 <description>Limits the number of processes that can be launched by
2422 processes launched by Apache children</description>
2423 <syntax>RLimitNPROC <var>number</var>|max [<var>number</var>|max]</syntax>
2424 <default>Unset; uses operating system defaults</default>
2425 <contextlist><context>server config</context><context>virtual host</context>
2426 <context>directory</context><context>.htaccess</context></contextlist>
2427 <override>All</override>
2430 <p>Takes 1 or 2 parameters. The first parameter sets the soft
2431 resource limit for all processes and the second parameter sets
2432 the maximum resource limit. Either parameter can be a number,
2433 or <code>max</code> to indicate to the server that the limit
2434 should be set to the maximum allowed by the operating system
2435 configuration. Raising the maximum resource limit requires that
2436 the server is running as <code>root</code>, or in the initial startup
2439 <p>This applies to processes forked off from Apache children
2440 servicing requests, not the Apache children themselves. This
2441 includes CGI scripts and SSI exec commands, but not any
2442 processes forked off from the Apache parent such as piped
2445 <p>Process limits control the number of processes per user.</p>
2447 <note><title>Note</title>
2448 <p>If CGI processes are <strong>not</strong> running
2449 under user ids other than the web server user id, this directive
2450 will limit the number of processes that the server itself can
2451 create. Evidence of this situation will be indicated by
2452 <strong><code>cannot fork</code></strong> messages in the
2453 <code>error_log</code>.</p>
2456 <seealso><directive module="core">RLimitMEM</directive></seealso>
2457 <seealso><directive module="core">RLimitCPU</directive></seealso>
2458 </directivesynopsis>
2461 <name>ScriptInterpreterSource</name>
2462 <description>Technique for locating the interpreter for CGI
2463 scripts</description>
2464 <syntax>ScriptInterpreterSource Registry|Registry-Strict|Script</syntax>
2465 <default>ScriptInterpreterSource Script</default>
2466 <contextlist><context>server config</context><context>virtual host</context>
2467 <context>directory</context><context>.htaccess</context></contextlist>
2468 <override>FileInfo</override>
2469 <compatibility>Win32 only;
2470 option <code>Registry-Strict</code> is available in Apache 2.0 and
2471 later</compatibility>
2474 <p>This directive is used to control how Apache finds the
2475 interpreter used to run CGI scripts. The default setting is
2476 <code>Script</code>. This causes Apache to use the interpreter pointed to
2477 by the shebang line (first line, starting with <code>#!</code>) in the
2478 script. On Win32 systems this line usually looks like:</p>
2481 #!C:/Perl/bin/perl.exe
2484 <p>or, if <code>perl</code> is in the <code>PATH</code>, simply:</p>
2490 <p>Setting <code>ScriptInterpreterSource Registry</code> will
2491 cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
2492 searched using the script file extension (e.g., <code>.pl</code>) as a
2493 search key. The command defined by the registry subkey
2494 <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
2495 <code>Shell\Open\Command</code> is used to open the script file. If the
2496 registry keys cannot be found, Apache falls back to the behavior of the
2497 <code>Script</code> option.</p>
2499 <note type="warning"><title>Security</title>
2500 <p>Be careful when using <code>ScriptInterpreterSource
2501 Registry</code> with <directive
2502 module="mod_alias">ScriptAlias</directive>'ed directories, because
2503 Apache will try to execute <strong>every</strong> file within this
2504 directory. The <code>Registry</code> setting may cause undesired
2505 program calls on files which are typically not executed. For
2506 example, the default open command on <code>.htm</code> files on
2507 most Windows systems will execute Microsoft Internet Explorer, so
2508 any HTTP request for an <code>.htm</code> file existing within the
2509 script directory would start the browser in the background on the
2510 server. This is a good way to crash your system within a minute or
2514 <p>The option <code>Registry-Strict</code> which is new in Apache
2515 2.0 does the same thing as <code>Registry</code> but uses only the
2516 subkey <code>Shell\ExecCGI\Command</code>. The
2517 <code>ExecCGI</code> key is not a common one. It must be
2518 configured manually in the windows registry and hence prevents
2519 accidental program calls on your system.</p>
2521 </directivesynopsis>
2524 <name>ServerAdmin</name>
2525 <description>Email address that the server includes in error
2526 messages sent to the client</description>
2527 <syntax>ServerAdmin <var>email-address</var>|<var>URL</var></syntax>
2528 <contextlist><context>server config</context><context>virtual host</context>
2532 <p>The <directive>ServerAdmin</directive> sets the contact address
2533 that the server includes in any error messages it returns to the
2534 client. If the <code>httpd</code> doesn't recognize the supplied argument
2536 assumes, that it's an <var>email-address</var> and prepends it with
2537 <code>mailto:</code> in hyperlink targets. However, it's recommended to
2538 actually use an email address, since there are a lot of CGI scripts that
2539 make that assumption. If you want to use an URL, it should point to another
2540 server under your control. Otherwise users may not be able to contact you in
2543 <p>It may be worth setting up a dedicated address for this, e.g.</p>
2546 ServerAdmin www-admin@foo.example.com
2548 <p>as users do not always mention that they are talking about the
2551 </directivesynopsis>
2554 <name>ServerAlias</name>
2555 <description>Alternate names for a host used when matching requests
2556 to name-virtual hosts</description>
2557 <syntax>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</syntax>
2558 <contextlist><context>virtual host</context></contextlist>
2561 <p>The <directive>ServerAlias</directive> directive sets the
2562 alternate names for a host, for use with <a
2563 href="../vhosts/name-based.html">name-based virtual hosts</a>. The
2564 <directive>ServerAlias</directive> may include wildcards, if appropriate.</p>
2567 <VirtualHost *><br />
2568 ServerName server.domain.com<br />
2569 ServerAlias server server2.domain.com server2<br />
2571 </VirtualHost>
2574 <seealso><a href="../vhosts/">Apache Virtual Host documentation</a></seealso>
2575 </directivesynopsis>
2578 <name>ServerName</name>
2579 <description>Hostname and port that the server uses to identify
2580 itself</description>
2581 <syntax>ServerName [<var>scheme</var>://]<var>fully-qualified-domain-name</var>[:<var>port</var>]</syntax>
2582 <contextlist><context>server config</context><context>virtual host</context>
2584 <compatibility>In version 2.0, this
2585 directive supersedes the functionality of the <directive>Port</directive>
2586 directive from version 1.3.</compatibility>
2589 <p>The <directive>ServerName</directive> directive sets the
2590 request scheme, hostname and
2591 port that the server uses to identify itself. This is used when
2592 creating redirection URLs. For example, if the name of the
2593 machine hosting the web server is <code>simple.example.com</code>,
2594 but the machine also has the DNS alias <code>www.example.com</code>
2595 and you wish the web server to be so identified, the following
2596 directive should be used:</p>
2599 ServerName www.example.com:80
2602 <p>If no <directive>ServerName</directive> is specified, then the
2603 server attempts to deduce the hostname by performing a reverse
2604 lookup on the IP address. If no port is specified in the
2605 <directive>ServerName</directive>, then the server will use the
2606 port from the incoming request. For optimal reliability and
2607 predictability, you should specify an explicit hostname and port
2608 using the <directive>ServerName</directive> directive.</p>
2610 <p>If you are using <a
2611 href="../vhosts/name-based.html">name-based virtual hosts</a>,
2612 the <directive>ServerName</directive> inside a
2613 <directive type="section" module="core">VirtualHost</directive>
2614 section specifies what hostname must appear in the request's
2615 <code>Host:</code> header to match this virtual host.</p>
2618 <p>Sometimes, the server runs behind a device that processes SSL,
2619 such as a reverse proxy, load balancer or SSL offload
2620 appliance. When this is the case, specify the
2621 <code>https://</code> scheme and the port number to which the
2622 clients connect in the <directive>ServerName</directive> directive
2623 to make sure that the server generates the correct
2624 self-referential URLs.
2627 <p>See the description of the
2628 <directive module="core">UseCanonicalName</directive> and
2629 <directive module="core">UseCanonicalPhysicalPort</directive>directives for
2630 settings which determine whether self-referential URLs (e.g., by the
2631 <module>mod_dir</module> module) will refer to the
2632 specified port, or to the port number given in the client's request.
2637 <seealso><a href="../dns-caveats.html">Issues Regarding DNS and
2638 Apache</a></seealso>
2639 <seealso><a href="../vhosts/">Apache virtual host
2640 documentation</a></seealso>
2641 <seealso><directive module="core">UseCanonicalName</directive></seealso>
2642 <seealso><directive module="core">UseCanonicalPhysicalPort</directive></seealso>
2643 <seealso><directive module="core">NameVirtualHost</directive></seealso>
2644 <seealso><directive module="core">ServerAlias</directive></seealso>
2645 </directivesynopsis>
2648 <name>ServerPath</name>
2649 <description>Legacy URL pathname for a name-based virtual host that
2650 is accessed by an incompatible browser</description>
2651 <syntax>ServerPath <var>URL-path</var></syntax>
2652 <contextlist><context>virtual host</context></contextlist>
2655 <p>The <directive>ServerPath</directive> directive sets the legacy
2656 URL pathname for a host, for use with <a
2657 href="../vhosts/">name-based virtual hosts</a>.</p>
2659 <seealso><a href="../vhosts/">Apache Virtual Host documentation</a></seealso>
2660 </directivesynopsis>
2663 <name>ServerRoot</name>
2664 <description>Base directory for the server installation</description>
2665 <syntax>ServerRoot <var>directory-path</var></syntax>
2666 <default>ServerRoot /usr/local/apache</default>
2667 <contextlist><context>server config</context></contextlist>
2670 <p>The <directive>ServerRoot</directive> directive sets the
2671 directory in which the server lives. Typically it will contain the
2672 subdirectories <code>conf/</code> and <code>logs/</code>. Relative
2673 paths in other configuration directives (such as <directive
2674 module="core">Include</directive> or <directive
2675 module="mod_so">LoadModule</directive>, for example) are taken as
2676 relative to this directory.</p>
2678 <example><title>Example</title>
2679 ServerRoot /home/httpd
2683 <seealso><a href="../invoking.html">the <code>-d</code>
2684 option to <code>httpd</code></a></seealso>
2685 <seealso><a href="../misc/security_tips.html#serverroot">the
2686 security tips</a> for information on how to properly set
2687 permissions on the <directive>ServerRoot</directive></seealso>
2688 </directivesynopsis>
2691 <name>ServerSignature</name>
2692 <description>Configures the footer on server-generated documents</description>
2693 <syntax>ServerSignature On|Off|EMail</syntax>
2694 <default>ServerSignature Off</default>
2695 <contextlist><context>server config</context><context>virtual host</context>
2696 <context>directory</context><context>.htaccess</context>
2698 <override>All</override>
2701 <p>The <directive>ServerSignature</directive> directive allows the
2702 configuration of a trailing footer line under server-generated
2703 documents (error messages, <module>mod_proxy</module> ftp directory
2704 listings, <module>mod_info</module> output, ...). The reason why you
2705 would want to enable such a footer line is that in a chain of proxies,
2706 the user often has no possibility to tell which of the chained servers
2707 actually produced a returned error message.</p>
2709 <p>The <code>Off</code>
2710 setting, which is the default, suppresses the footer line (and is
2711 therefore compatible with the behavior of Apache-1.2 and
2712 below). The <code>On</code> setting simply adds a line with the
2713 server version number and <directive
2714 module="core">ServerName</directive> of the serving virtual host,
2715 and the <code>EMail</code> setting additionally creates a
2716 "mailto:" reference to the <directive
2717 module="core">ServerAdmin</directive> of the referenced
2720 <p>After version 2.0.44, the details of the server version number
2721 presented are controlled by the <directive
2722 module="core">ServerTokens</directive> directive.</p>
2724 <seealso><directive module="core">ServerTokens</directive></seealso>
2725 </directivesynopsis>
2728 <name>ServerTokens</name>
2729 <description>Configures the <code>Server</code> HTTP response
2730 header</description>
2731 <syntax>ServerTokens Major|Minor|Min[imal]|Prod[uctOnly]|OS|Full</syntax>
2732 <default>ServerTokens Full</default>
2733 <contextlist><context>server config</context></contextlist>
2736 <p>This directive controls whether <code>Server</code> response
2737 header field which is sent back to clients includes a
2738 description of the generic OS-type of the server as well as
2739 information about compiled-in modules.</p>
2742 <dt><code>ServerTokens Prod[uctOnly]</code></dt>
2744 <dd>Server sends (<em>e.g.</em>): <code>Server:
2747 <dt><code>ServerTokens Major</code></dt>
2749 <dd>Server sends (<em>e.g.</em>): <code>Server:
2750 Apache/2</code></dd>
2752 <dt><code>ServerTokens Minor</code></dt>
2754 <dd>Server sends (<em>e.g.</em>): <code>Server:
2755 Apache/2.0</code></dd>
2757 <dt><code>ServerTokens Min[imal]</code></dt>
2759 <dd>Server sends (<em>e.g.</em>): <code>Server:
2760 Apache/2.0.41</code></dd>
2762 <dt><code>ServerTokens OS</code></dt>
2764 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.0.41
2767 <dt><code>ServerTokens Full</code> (or not specified)</dt>
2769 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.0.41
2770 (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
2773 <p>This setting applies to the entire server, and cannot be
2774 enabled or disabled on a virtualhost-by-virtualhost basis.</p>
2776 <p>After version 2.0.44, this directive also controls the
2777 information presented by the <directive
2778 module="core">ServerSignature</directive> directive.</p>
2780 <seealso><directive module="core">ServerSignature</directive></seealso>
2781 </directivesynopsis>
2784 <name>SetHandler</name>
2785 <description>Forces all matching files to be processed by a
2786 handler</description>
2787 <syntax>SetHandler <var>handler-name</var>|None</syntax>
2788 <contextlist><context>server config</context><context>virtual host</context>
2789 <context>directory</context><context>.htaccess</context>
2791 <override>FileInfo</override>
2792 <compatibility>Moved into the core in Apache 2.0</compatibility>
2795 <p>When placed into an <code>.htaccess</code> file or a
2796 <directive type="section" module="core">Directory</directive> or
2797 <directive type="section" module="core">Location</directive>
2798 section, this directive forces all matching files to be parsed
2799 through the <a href="../handler.html">handler</a> given by
2800 <var>handler-name</var>. For example, if you had a directory you
2801 wanted to be parsed entirely as imagemap rule files, regardless
2802 of extension, you might put the following into an
2803 <code>.htaccess</code> file in that directory:</p>
2806 SetHandler imap-file
2809 <p>Another example: if you wanted to have the server display a
2810 status report whenever a URL of
2811 <code>http://servername/status</code> was called, you might put
2812 the following into <code>httpd.conf</code>:</p>
2815 <Location /status><br />
2817 SetHandler server-status<br />
2822 <p>You can override an earlier defined <directive>SetHandler</directive>
2823 directive by using the value <code>None</code>.</p>
2824 <p><strong>Note:</strong> because SetHandler overrides default handlers,
2825 normal behaviour such as handling of URLs ending in a slash (/) as
2826 directories or index files is suppressed.</p>
2829 <seealso><directive module="mod_mime">AddHandler</directive></seealso>
2831 </directivesynopsis>
2834 <name>SetInputFilter</name>
2835 <description>Sets the filters that will process client requests and POST
2837 <syntax>SetInputFilter <var>filter</var>[;<var>filter</var>...]</syntax>
2838 <contextlist><context>server config</context><context>virtual host</context>
2839 <context>directory</context><context>.htaccess</context>
2841 <override>FileInfo</override>
2844 <p>The <directive>SetInputFilter</directive> directive sets the
2845 filter or filters which will process client requests and POST
2846 input when they are received by the server. This is in addition to
2847 any filters defined elsewhere, including the
2848 <directive module="mod_mime">AddInputFilter</directive>
2851 <p>If more than one filter is specified, they must be separated
2852 by semicolons in the order in which they should process the
2855 <seealso><a href="../filter.html">Filters</a> documentation</seealso>
2856 </directivesynopsis>
2859 <name>SetOutputFilter</name>
2860 <description>Sets the filters that will process responses from the
2861 server</description>
2862 <syntax>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</syntax>
2863 <contextlist><context>server config</context><context>virtual host</context>
2864 <context>directory</context><context>.htaccess</context>
2866 <override>FileInfo</override>
2869 <p>The <directive>SetOutputFilter</directive> directive sets the filters
2870 which will process responses from the server before they are
2871 sent to the client. This is in addition to any filters defined
2872 elsewhere, including the
2873 <directive module="mod_mime">AddOutputFilter</directive>
2876 <p>For example, the following configuration will process all files
2877 in the <code>/www/data/</code> directory for server-side
2881 <Directory /www/data/><br />
2883 SetOutputFilter INCLUDES<br />
2888 <p>If more than one filter is specified, they must be separated
2889 by semicolons in the order in which they should process the
2892 <seealso><a href="../filter.html">Filters</a> documentation</seealso>
2893 </directivesynopsis>
2896 <name>TimeOut</name>
2897 <description>Amount of time the server will wait for
2898 certain events before failing a request</description>
2899 <syntax>TimeOut <var>seconds</var></syntax>
2900 <default>TimeOut 300</default>
2901 <contextlist><context>server config</context><context>virtual host</context></contextlist>
2904 <p>The <directive>TimeOut</directive> directive currently defines
2905 the amount of time Apache will wait for three things:</p>
2908 <li>The total amount of time it takes to receive a GET
2911 <li>The amount of time between receipt of TCP packets on a
2912 POST or PUT request.</li>
2914 <li>The amount of time between ACKs on transmissions of TCP
2915 packets in responses.</li>
2918 <p>We plan on making these separately configurable at some point
2919 down the road. The timer used to default to 1200 before 1.2,
2920 but has been lowered to 300 which is still far more than
2921 necessary in most situations. It is not set any lower by
2922 default because there may still be odd places in the code where
2923 the timer is not reset when a packet is sent. </p>
2925 </directivesynopsis>
2928 <name>TraceEnable</name>
2929 <description>Determines the behaviour on <code>TRACE</code>
2930 requests</description>
2931 <syntax>TraceEnable <var>[on|off|extended]</var></syntax>
2932 <default>TraceEnable on</default>
2933 <contextlist><context>server config</context></contextlist>
2934 <compatibility>Available in Apache 1.3.34, 2.0.55 and later</compatibility>
2937 <p>This directive overrides the behavior of <code>TRACE</code> for both
2938 the core server and <module>mod_proxy</module>. The default
2939 <code>TraceEnable on</code> permits <code>TRACE</code> requests per
2940 RFC 2616, which disallows any request body to accompany the request.
2941 <code>TraceEnable off</code> causes the core server and
2942 <module>mod_proxy</module> to return a <code>405</code> (Method not
2943 allowed) error to the client.</p>
2945 <p>Finally, for testing and diagnostic purposes only, request
2946 bodies may be allowed using the non-compliant <code>TraceEnable
2947 extended</code> directive. The core (as an origin server) will
2948 restrict the request body to 64k (plus 8k for chunk headers if
2949 <code>Transfer-Encoding: chunked</code> is used). The core will
2950 reflect the full headers and all chunk headers with the response
2951 body. As a proxy server, the request body is not restricted to 64k.</p>
2953 </directivesynopsis>
2956 <name>UseCanonicalName</name>
2957 <description>Configures how the server determines its own name and
2959 <syntax>UseCanonicalName On|Off|DNS</syntax>
2960 <default>UseCanonicalName Off</default>
2961 <contextlist><context>server config</context><context>virtual host</context>
2962 <context>directory</context></contextlist>
2965 <p>In many situations Apache must construct a <em>self-referential</em>
2966 URL -- that is, a URL that refers back to the same server. With
2967 <code>UseCanonicalName On</code> Apache will use the hostname and port
2968 specified in the <directive module="core">ServerName</directive>
2969 directive to construct the canonical name for the server. This name
2970 is used in all self-referential URLs, and for the values of
2971 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>
2973 <p>With <code>UseCanonicalName Off</code> Apache will form
2974 self-referential URLs using the hostname and port supplied by
2975 the client if any are supplied (otherwise it will use the
2976 canonical name, as defined above). These values are the same
2977 that are used to implement <a
2978 href="../vhosts/name-based.html">name based virtual hosts</a>,
2979 and are available with the same clients. The CGI variables
2980 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
2981 constructed from the client supplied values as well.</p>
2983 <p>An example where this may be useful is on an intranet server
2984 where you have users connecting to the machine using short
2985 names such as <code>www</code>. You'll notice that if the users
2986 type a shortname, and a URL which is a directory, such as
2987 <code>http://www/splat</code>, <em>without the trailing
2988 slash</em> then Apache will redirect them to
2989 <code>http://www.domain.com/splat/</code>. If you have
2990 authentication enabled, this will cause the user to have to
2991 authenticate twice (once for <code>www</code> and once again
2992 for <code>www.domain.com</code> -- see <a
2993 href="http://httpd.apache.org/docs/misc/FAQ.html#prompted-twice">the
2994 FAQ on this subject for more information</a>). But if
2995 <directive>UseCanonicalName</directive> is set <code>Off</code>, then
2996 Apache will redirect to <code>http://www/splat/</code>.</p>
2998 <p>There is a third option, <code>UseCanonicalName DNS</code>,
2999 which is intended for use with mass IP-based virtual hosting to
3000 support ancient clients that do not provide a
3001 <code>Host:</code> header. With this option Apache does a
3002 reverse DNS lookup on the server IP address that the client
3003 connected to in order to work out self-referential URLs.</p>
3005 <note type="warning"><title>Warning</title>
3006 <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>
3007 they may be broken by this option. The client is essentially free
3008 to give whatever value they want as a hostname. But if the CGI is
3009 only using <code>SERVER_NAME</code> to construct self-referential URLs
3010 then it should be just fine.</p>
3013 <seealso><directive module="core">UseCanonicalPhysicalPort</directive></seealso>
3014 <seealso><directive module="core">ServerName</directive></seealso>
3015 <seealso><directive module="mpm_common">Listen</directive></seealso>
3016 </directivesynopsis>
3019 <name>UseCanonicalPhysicalPort</name>
3020 <description>Configures how the server determines its own name and
3022 <syntax>UseCanonicalPhysicalPort On|Off</syntax>
3023 <default>UseCanonicalPhysicalPort Off</default>
3024 <contextlist><context>server config</context><context>virtual host</context>
3025 <context>directory</context></contextlist>
3028 <p>In many situations Apache must construct a <em>self-referential</em>
3029 URL -- that is, a URL that refers back to the same server. With
3030 <code>UseCanonicalPhysicalPort On</code> Apache will, when
3031 constructing the canonical port for the server to honor
3032 the <directive module="core">UseCanonicalName</directive> directive,
3033 provide the actual physical port number being used by this request
3034 as a potential port. With <code>UseCanonicalPhysicalPort Off</code>
3035 Apache will not ever use the actual physical port number, instead
3036 relying on all configured information to construct a valid port number.</p>
3038 <note><title>Note</title>
3039 <p>The ordering of when the physical port is used is as follows:<br /><br />
3040 <code>UseCanonicalName On</code></p>
3042 <li>Port provided in <code>Servername</code></li>
3043 <li>Physical port</li>
3044 <li>Default port</li>
3046 <code>UseCanonicalName Off | DNS</code>
3048 <li>Parsed port from <code>Host:</code> header</li>
3049 <li>Physical port</li>
3050 <li>Port provided in <code>Servername</code></li>
3051 <li>Default port</li>
3054 <p>With <code>UseCanonicalPhysicalPort Off</code>, the
3055 physical ports are removed from the ordering.</p>
3059 <seealso><directive module="core">UseCanonicalName</directive></seealso>
3060 <seealso><directive module="core">ServerName</directive></seealso>
3061 <seealso><directive module="mpm_common">Listen</directive></seealso>
3062 </directivesynopsis>
3064 <directivesynopsis type="section">
3065 <name>VirtualHost</name>
3066 <description>Contains directives that apply only to a specific
3067 hostname or IP address</description>
3068 <syntax><VirtualHost
3069 <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
3070 ...> ... </VirtualHost></syntax>
3071 <contextlist><context>server config</context></contextlist>
3074 <p><directive type="section">VirtualHost</directive> and
3075 <code></VirtualHost></code> are used to enclose a group of
3076 directives that will apply only to a particular virtual host. Any
3077 directive that is allowed in a virtual host context may be
3078 used. When the server receives a request for a document on a
3079 particular virtual host, it uses the configuration directives
3080 enclosed in the <directive type="section">VirtualHost</directive>
3081 section. <var>Addr</var> can be:</p>
3084 <li>The IP address of the virtual host;</li>
3086 <li>A fully qualified domain name for the IP address of the
3087 virtual host (not recommended);</li>
3089 <li>The character <code>*</code>, which is used only in combination with
3090 <code>NameVirtualHost *</code> to match all IP addresses; or</li>
3092 <li>The string <code>_default_</code>, which is used only
3093 with IP virtual hosting to catch unmatched IP addresses.</li>
3096 <example><title>Example</title>
3097 <VirtualHost 10.1.2.3><br />
3099 ServerAdmin webmaster@host.foo.com<br />
3100 DocumentRoot /www/docs/host.foo.com<br />
3101 ServerName host.foo.com<br />
3102 ErrorLog logs/host.foo.com-error_log<br />
3103 TransferLog logs/host.foo.com-access_log<br />
3105 </VirtualHost>
3109 <p>IPv6 addresses must be specified in square brackets because
3110 the optional port number could not be determined otherwise. An
3111 IPv6 example is shown below:</p>
3114 <VirtualHost [2001:db8::a00:20ff:fea7:ccea]><br />
3116 ServerAdmin webmaster@host.example.com<br />
3117 DocumentRoot /www/docs/host.example.com<br />
3118 ServerName host.example.com<br />
3119 ErrorLog logs/host.example.com-error_log<br />
3120 TransferLog logs/host.example.com-access_log<br />
3122 </VirtualHost>
3125 <p>Each Virtual Host must correspond to a different IP address,
3126 different port number or a different host name for the server,
3127 in the former case the server machine must be configured to
3128 accept IP packets for multiple addresses. (If the machine does
3129 not have multiple network interfaces, then this can be
3130 accomplished with the <code>ifconfig alias</code> command -- if
3131 your OS supports it).</p>
3133 <note><title>Note</title>
3134 <p>The use of <directive type="section">VirtualHost</directive> does
3135 <strong>not</strong> affect what addresses Apache listens on. You
3136 may need to ensure that Apache is listening on the correct addresses
3137 using <directive module="mpm_common">Listen</directive>.</p>
3140 <p>When using IP-based virtual hosting, the special name
3141 <code>_default_</code> can be specified in
3142 which case this virtual host will match any IP address that is
3143 not explicitly listed in another virtual host. In the absence
3144 of any <code>_default_</code> virtual host the "main" server config,
3145 consisting of all those definitions outside any VirtualHost
3146 section, is used when no IP-match occurs. (But note that any IP
3147 address that matches a <directive
3148 module="core">NameVirtualHost</directive> directive will use neither
3149 the "main" server config nor the <code>_default_</code> virtual host.
3150 See the <a href="../vhosts/name-based.html">name-based virtual hosting</a>
3151 documentation for further details.)</p>
3153 <p>You can specify a <code>:port</code> to change the port that is
3154 matched. If unspecified then it defaults to the same port as the
3155 most recent <directive module="mpm_common">Listen</directive>
3156 statement of the main server. You may also specify <code>:*</code>
3157 to match all ports on that address. (This is recommended when used
3158 with <code>_default_</code>.)</p>
3160 <note type="warning"><title>Security</title>
3161 <p>See the <a href="../misc/security_tips.html">security tips</a>
3162 document for details on why your security could be compromised if the
3163 directory where log files are stored is writable by anyone other
3164 than the user that starts the server.</p>
3167 <seealso><a href="../vhosts/">Apache Virtual Host documentation</a></seealso>
3168 <seealso><a href="../dns-caveats.html">Issues Regarding DNS and
3169 Apache</a></seealso>
3170 <seealso><a href="../bind.html">Setting
3171 which addresses and ports Apache uses</a></seealso>
3172 <seealso><a href="../sections.html">How <Directory>, <Location>
3173 and <Files> sections work</a> for an explanation of how these
3174 different sections are combined when a request is received</seealso>
3175 </directivesynopsis>