docs/manual/mod/core.html.en - httpd - Git at Google

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 <p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p>
 <p class="apache">Apache HTTP Server Version 2.0</p>
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 <a href="http://www.apache.org/">Apache</a> &gt; <a href="http://httpd.apache.org/">HTTP Server</a> &gt; <a href="http://httpd.apache.org/docs/">Documentation</a> &gt; <a href="../">Version 2.0</a> &gt; <a href="./">Modules</a></div>
 <div id="page-content">
 <div class="retired"><h4>Please note</h4>
             <p>This document refers to the <strong>2.0</strong> version of Apache httpd, which <strong>is no longer maintained</strong>. Upgrade, and refer to the current version of httpd instead, documented at:</p>
         <ul><li><a href="http://httpd.apache.org/docs/current/">Current release version of Apache HTTP Server documentation</a></li></ul><p>You may follow <a href="http://httpd.apache.org/docs/current/mod/core.html">this link</a> to go to the current version of this document.</p></div><div id="preamble"><h1>Apache Core Features</h1>
 <div class="toplang">
 <p><span>Available Languages: </span><a href="../de/mod/core.html" hreflang="de" rel="alternate" title="Deutsch">&nbsp;de&nbsp;</a> |
 <a href="../en/mod/core.html" title="English">&nbsp;en&nbsp;</a> |
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 </div>
 <table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Core Apache HTTP Server features that are always
 available</td></tr>
 <tr><th><a href="module-dict.html#Status">Status:</a></th><td>Core</td></tr></table>
 </div>
 <div id="quickview"><h3 class="directives">Directives</h3>
 <ul id="toc">
 <li><img alt="" src="../images/down.gif" /> <a href="#acceptpathinfo">AcceptPathInfo</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#accessfilename">AccessFileName</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#adddefaultcharset">AddDefaultCharset</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#addoutputfilterbytype">AddOutputFilterByType</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#allowencodedslashes">AllowEncodedSlashes</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#allowoverride">AllowOverride</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#authname">AuthName</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#authtype">AuthType</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#cgimapextension">CGIMapExtension</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#contentdigest">ContentDigest</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#defaulttype">DefaultType</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#directory">&lt;Directory&gt;</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#directorymatch">&lt;DirectoryMatch&gt;</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#documentroot">DocumentRoot</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#enablemmap">EnableMMAP</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#enablesendfile">EnableSendfile</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#errordocument">ErrorDocument</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#errorlog">ErrorLog</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#fileetag">FileETag</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#files">&lt;Files&gt;</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#filesmatch">&lt;FilesMatch&gt;</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#forcetype">ForceType</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#hostnamelookups">HostnameLookups</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#identitycheck">IdentityCheck</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#ifdefine">&lt;IfDefine&gt;</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#ifmodule">&lt;IfModule&gt;</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#include">Include</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#keepalive">KeepAlive</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#keepalivetimeout">KeepAliveTimeout</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#limit">&lt;Limit&gt;</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#limitexcept">&lt;LimitExcept&gt;</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#limitinternalrecursion">LimitInternalRecursion</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestbody">LimitRequestBody</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfields">LimitRequestFields</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestfieldsize">LimitRequestFieldSize</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#limitrequestline">LimitRequestLine</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#limitxmlrequestbody">LimitXMLRequestBody</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#location">&lt;Location&gt;</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#locationmatch">&lt;LocationMatch&gt;</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#loglevel">LogLevel</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#maxranges">MaxRanges</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#namevirtualhost">NameVirtualHost</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#options">Options</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#require">Require</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitcpu">RLimitCPU</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitmem">RLimitMEM</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#rlimitnproc">RLimitNPROC</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#satisfy">Satisfy</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#scriptinterpretersource">ScriptInterpreterSource</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#serveradmin">ServerAdmin</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#serveralias">ServerAlias</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#servername">ServerName</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#serverpath">ServerPath</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#serverroot">ServerRoot</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#serversignature">ServerSignature</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#servertokens">ServerTokens</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#sethandler">SetHandler</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#setinputfilter">SetInputFilter</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#setoutputfilter">SetOutputFilter</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#timeout">TimeOut</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#traceenable">TraceEnable</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#usecanonicalname">UseCanonicalName</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#virtualhost">&lt;VirtualHost&gt;</a></li>
 </ul>
 </div>

 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="AcceptPathInfo" id="AcceptPathInfo">AcceptPathInfo</a> <a name="acceptpathinfo" id="acceptpathinfo">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Resources accept trailing pathname information</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptPathInfo On|Off|Default</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AcceptPathInfo Default</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.0.30 and later</td></tr>
 </table>

     <p>This directive controls whether requests that contain trailing
     pathname information that follows an actual filename (or
     non-existent file in an existing directory) will be accepted or
     rejected.  The trailing pathname information can be made
     available to scripts in the <code>PATH_INFO</code> environment
     variable.</p>

     <p>For example, assume the location <code>/test/</code> points to
     a directory that contains only the single file
     <code>here.html</code>.  Then requests for
     <code>/test/here.html/more</code> and
     <code>/test/nothere.html/more</code> both collect
     <code>/more</code> as <code>PATH_INFO</code>.</p>

     <p>The three possible arguments for the
     <code class="directive">AcceptPathInfo</code> directive are:</p>
     <dl>
     <dt><code>Off</code></dt><dd>A request will only be accepted if it
     maps to a literal path that exists.  Therefore a request with
     trailing pathname information after the true filename such as
     <code>/test/here.html/more</code> in the above example will return
     a 404 NOT FOUND error.</dd>

     <dt><code>On</code></dt><dd>A request will be accepted if a
     leading path component maps to a file that exists.  The above
     example <code>/test/here.html/more</code> will be accepted if
     <code>/test/here.html</code> maps to a valid file.</dd>

     <dt><code>Default</code></dt><dd>The treatment of requests with
     trailing pathname information is determined by the <a href="../handler.html">handler</a> responsible for the request.
     The core handler for normal files defaults to rejecting
     <code>PATH_INFO</code> requests. Handlers that serve scripts, such as <a href="mod_cgi.html">cgi-script</a> and <a href="mod_isapi.html">isapi-handler</a>, generally accept
     <code>PATH_INFO</code> by default.</dd>
     </dl>

     <p>The primary purpose of the <code>AcceptPathInfo</code>
     directive is to allow you to override the handler's choice of
     accepting or rejecting <code>PATH_INFO</code>. This override is required,
     for example, when you use a <a href="../filter.html">filter</a>, such
     as <a href="mod_include.html">INCLUDES</a>, to generate content
     based on <code>PATH_INFO</code>.  The core handler would usually reject
     the request, so you can use the following configuration to enable
     such a script:</p>

     <div class="example"><p><code>
       &lt;Files "mypaths.shtml"&gt;<br />
       <span class="indent">
         Options +Includes<br />
         SetOutputFilter INCLUDES<br />
         AcceptPathInfo On<br />
       </span>
       &lt;/Files&gt;
     </code></p></div>


 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="AccessFileName" id="AccessFileName">AccessFileName</a> <a name="accessfilename" id="accessfilename">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Name of the distributed configuration file</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AccessFileName <var>filename</var> [<var>filename</var>] ...</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AccessFileName .htaccess</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>While processing a request the server looks for
     the first existing configuration file from this list of names in
     every directory of the path to the document, if distributed
     configuration files are <a href="#allowoverride">enabled for that
     directory</a>. For example:</p>

     <div class="example"><p><code>
       AccessFileName .acl
     </code></p></div>

     <p>before returning the document
     <code>/usr/local/web/index.html</code>, the server will read
     <code>/.acl</code>, <code>/usr/.acl</code>,
     <code>/usr/local/.acl</code> and <code>/usr/local/web/.acl</code>
     for directives, unless they have been disabled with</p>

     <div class="example"><p><code>
       &lt;Directory /&gt;<br />
       <span class="indent">
         AllowOverride None<br />
       </span>
       &lt;/Directory&gt;
     </code></p></div>

 <h3>See also</h3>
 <ul>
 <li><code class="directive"><a href="#allowoverride">AllowOverride</a></code></li>
 <li><a href="../configuring.html">Configuration Files</a></li>
 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="AddDefaultCharset" id="AddDefaultCharset">AddDefaultCharset</a> <a name="adddefaultcharset" id="adddefaultcharset">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Default charset parameter to be added when a response
 content-type is <code>text/plain</code> or <code>text/html</code></td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AddDefaultCharset On|Off|<var>charset</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AddDefaultCharset Off</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>This directive specifies a default value for the media type
     charset parameter (the name of a character encoding) to be added
     to a response if and only if the response's content-type is either
     <code>text/plain</code> or <code>text/html</code>.  This should override
     any charset specified in the body of the response via a <code>META</code>
     element, though the exact behavior is often dependent on the user's client
     configuration. A setting of <code>AddDefaultCharset Off</code>
     disables this functionality. <code>AddDefaultCharset On</code> enables
     a default charset of <code>iso-8859-1</code>. Any other value is assumed
     to be the <var>charset</var> to be used, which should be one of the
     <a href="http://www.iana.org/assignments/character-sets">IANA registered
     charset values</a> for use in MIME media types.
     For example:</p>

     <div class="example"><p><code>
       AddDefaultCharset utf-8
     </code></p></div>

     <p><code class="directive">AddDefaultCharset</code> should only be used when all
     of the text resources to which it applies are known to be in that
     character encoding and it is too inconvenient to label their charset
     individually. One such example is to add the charset parameter
     to resources containing generated content, such as legacy CGI
     scripts, that might be vulnerable to cross-site scripting attacks
     due to user-provided data being included in the output.  Note, however,
     that a better solution is to just fix (or delete) those scripts, since
     setting a default charset does not protect users that have enabled
     the "auto-detect character encoding" feature on their browser.</p>

 <h3>See also</h3>
 <ul>
 <li><code class="directive"><a href="../mod/mod_mime.html#addcharset">AddCharset</a></code></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="AddOutputFilterByType" id="AddOutputFilterByType">AddOutputFilterByType</a> <a name="addoutputfilterbytype" id="addoutputfilterbytype">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>assigns an output filter to a particular MIME-type</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AddOutputFilterByType <var>filter</var>[;<var>filter</var>...]
 <var>MIME-type</var> [<var>MIME-type</var>] ...</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.0.33 and later</td></tr>
 </table>
     <p>This directive activates a particular output <a href="../filter.html">filter</a> for a request depending on the
     response MIME-type.</p>

     <p>The following example uses the <code>DEFLATE</code> filter, which
     is provided by <code class="module"><a href="../mod/mod_deflate.html">mod_deflate</a></code>. It will compress all
     output (either static or dynamic) which is labeled as
     <code>text/html</code> or <code>text/plain</code> before it is sent
     to the client.</p>

     <div class="example"><p><code>
       AddOutputFilterByType DEFLATE text/html text/plain
     </code></p></div>

     <p>If you want the content to be processed by more than one filter, their
     names have to be separated by semicolons. It's also possible to use one
     <code class="directive">AddOutputFilterByType</code> directive for each of
     these filters.</p>

     <p>The configuration below causes all script output labeled as
     <code>text/html</code> to be processed at first by the
     <code>INCLUDES</code> filter and then by the <code>DEFLATE</code>
     filter.</p>

     <div class="example"><p><code>
     &lt;Location /cgi-bin/&gt;<br />
     <span class="indent">
       Options Includes<br />
       AddOutputFilterByType INCLUDES;DEFLATE text/html<br />
     </span>
     &lt;/Location&gt;
     </code></p></div>

     <div class="warning"><h3>Note</h3>
       <p>Enabling filters with <code class="directive">AddOutputFilterByType</code>
       may fail partially or completely in some cases. For example, no
       filters are applied if the MIME-type could not be determined  and falls
       back to the <code class="directive"><a href="#defaulttype">DefaultType</a></code> setting,
       even if the <code class="directive"><a href="#defaulttype">DefaultType</a></code> is the
       same.</p>

       <p>However, if you want to make sure, that the filters will be
       applied, assign the content type to a resource explicitly, for
       example with <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code> or
       <code class="directive"><a href="#forcetype">ForceType</a></code>. Setting the
       content type within a (non-nph) CGI script is also safe.</p>

       <p>The by-type output filters are never applied on proxy requests.</p>
     </div>

 <h3>See also</h3>
 <ul>
 <li><code class="directive"><a href="../mod/mod_mime.html#addoutputfilter">AddOutputFilter</a></code></li>
 <li><code class="directive"><a href="#setoutputfilter">SetOutputFilter</a></code></li>
 <li><a href="../filter.html">filters</a></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="AllowEncodedSlashes" id="AllowEncodedSlashes">AllowEncodedSlashes</a> <a name="allowencodedslashes" id="allowencodedslashes">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines whether encoded path separators in URLs are allowed to
 be passed through</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowEncodedSlashes On|Off</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowEncodedSlashes Off</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.0.46 and later</td></tr>
 </table>
     <p>The <code class="directive">AllowEncodedSlashes</code> directive allows URLs
     which contain encoded path separators (<code>%2F</code> for <code>/</code>
     and additionally <code>%5C</code> for <code>\</code> on according systems)
     to be used. Normally such URLs are refused with a 404 (Not found) error.</p>

     <p>Turning <code class="directive">AllowEncodedSlashes</code> <code>On</code> is
     mostly useful when used in conjunction with <code>PATH_INFO</code>.</p>

     <div class="note"><h3>Note</h3>
       <p>Allowing encoded slashes does <em>not</em> imply <em>decoding</em>.
       Occurrences of <code>%2F</code> or <code>%5C</code> (<em>only</em> on
       according systems) will be left as such in the otherwise decoded URL
       string.</p>
     </div>

 <h3>See also</h3>
 <ul>
 <li><code class="directive"><a href="#acceptpathinfo">AcceptPathInfo</a></code></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="AllowOverride" id="AllowOverride">AllowOverride</a> <a name="allowoverride" id="allowoverride">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Types of directives that are allowed in
 <code>.htaccess</code> files</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowOverride All|None|<var>directive-type</var>
 [<var>directive-type</var>] ...</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowOverride All</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>When the server finds an <code>.htaccess</code> file (as
     specified by <code class="directive"><a href="#accessfilename">AccessFileName</a></code>)
     it needs to know which directives declared in that file can override
     earlier configuration directives.</p>

     <div class="note"><h3>Only available in &lt;Directory&gt; sections</h3>
     <code class="directive">AllowOverride</code> is valid only in
     <code class="directive"><a href="#directory">&lt;Directory&gt;</a></code>
     sections specified without regular expressions, not in <code class="directive"><a href="#location">&lt;Location&gt;</a></code>, <code class="directive"><a href="#directorymatch">&lt;DirectoryMatch&gt;</a></code> or
     <code class="directive"><a href="#files">&lt;Files&gt;</a></code> sections.
     </div>

     <p>When this directive is set to <code>None</code>, then
     <a href="#accessfilename">.htaccess</a> files are completely ignored.
     In this case, the server will not even attempt to read
     <code>.htaccess</code> files in the filesystem.</p>

     <p>When this directive is set to <code>All</code>, then any
     directive which has the .htaccess <a href="directive-dict.html#Context">Context</a> is allowed in
     <code>.htaccess</code> files.</p>

     <p>The <var>directive-type</var> can be one of the following
     groupings of directives.</p>

     <dl>
       <dt>AuthConfig</dt>

       <dd>

       Allow use of the authorization directives (<code class="directive"><a href="../mod/mod_auth_dbm.html#authdbmgroupfile">AuthDBMGroupFile</a></code>,
       <code class="directive"><a href="../mod/mod_auth_dbm.html#authdbmuserfile">AuthDBMUserFile</a></code>,
       <code class="directive"><a href="../mod/mod_auth.html#authgroupfile">AuthGroupFile</a></code>,
       <code class="directive"><a href="#authname">AuthName</a></code>,
       <code class="directive"><a href="#authtype">AuthType</a></code>, <code class="directive"><a href="../mod/mod_auth.html#authuserfile">AuthUserFile</a></code>, <code class="directive"><a href="#require">Require</a></code>, <em>etc.</em>).</dd>

       <dt>FileInfo</dt>

       <dd>
       Allow use of the directives controlling document types (<code class="directive"><a href="#defaulttype">DefaultType</a></code>, <code class="directive"><a href="#errordocument">ErrorDocument</a></code>, <code class="directive"><a href="#forcetype">ForceType</a></code>, <code class="directive"><a href="../mod/mod_negotiation.html#languagepriority">LanguagePriority</a></code>,
       <code class="directive"><a href="#sethandler">SetHandler</a></code>, <code class="directive"><a href="#setinputfilter">SetInputFilter</a></code>, <code class="directive"><a href="#setoutputfilter">SetOutputFilter</a></code>, and
       <code class="module"><a href="../mod/mod_mime.html">mod_mime</a></code> Add* and Remove*
       directives, <em>etc.</em>).</dd>

       <dt>Indexes</dt>

       <dd>
       Allow use of the directives controlling directory indexing
       (<code class="directive"><a href="../mod/mod_autoindex.html#adddescription">AddDescription</a></code>,
       <code class="directive"><a href="../mod/mod_autoindex.html#addicon">AddIcon</a></code>, <code class="directive"><a href="../mod/mod_autoindex.html#addiconbyencoding">AddIconByEncoding</a></code>,
       <code class="directive"><a href="../mod/mod_autoindex.html#addiconbytype">AddIconByType</a></code>,
       <code class="directive"><a href="../mod/mod_autoindex.html#defaulticon">DefaultIcon</a></code>, <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>, <code class="directive"><a href="../mod/mod_autoindex.html#fancyindexing">FancyIndexing</a></code>, <code class="directive"><a href="../mod/mod_autoindex.html#headername">HeaderName</a></code>, <code class="directive"><a href="../mod/mod_autoindex.html#indexignore">IndexIgnore</a></code>, <code class="directive"><a href="../mod/mod_autoindex.html#indexoptions">IndexOptions</a></code>, <code class="directive"><a href="../mod/mod_autoindex.html#readmename">ReadmeName</a></code>,
       <em>etc.</em>).</dd>

       <dt>Limit</dt>

       <dd>
       Allow use of the directives controlling host access (<code class="directive"><a href="../mod/mod_access.html#allow">Allow</a></code>, <code class="directive"><a href="../mod/mod_access.html#deny">Deny</a></code> and <code class="directive"><a href="../mod/mod_access.html#order">Order</a></code>).</dd>

       <dt>Options</dt>

       <dd>
       Allow use of the directives controlling specific directory
       features (<code class="directive"><a href="#options">Options</a></code> and
       <code class="directive"><a href="../mod/mod_include.html#xbithack">XBitHack</a></code>).</dd>
     </dl>

     <p>Example:</p>

     <div class="example"><p><code>
       AllowOverride AuthConfig Indexes
     </code></p></div>

     <p>In the example above all directives that are neither in the group
     <code>AuthConfig</code> nor <code>Indexes</code> cause an internal
     server error.</p>

 <h3>See also</h3>
 <ul>
 <li><code class="directive"><a href="#accessfilename">AccessFileName</a></code></li>
 <li><a href="../configuring.html">Configuration Files</a></li>
 <li><a href="../howto/htaccess.html">.htaccess Files</a></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="AuthName" id="AuthName">AuthName</a> <a name="authname" id="authname">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Authorization realm for use in HTTP
 authentication</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AuthName <var>auth-domain</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>This directive sets the name of the authorization realm for a
     directory. This realm is given to the client so that the user
     knows which username and password to send.
     <code class="directive">AuthName</code> takes a single argument; if the
     realm name contains spaces, it must be enclosed in quotation
     marks.  It must be accompanied by <code class="directive"><a href="#authtype">AuthType</a></code> and <code class="directive"><a href="#require">Require</a></code> directives, and directives such
     as <code class="directive"><a href="../mod/mod_auth.html#authuserfile">AuthUserFile</a></code> and
     <code class="directive"><a href="../mod/mod_auth.html#authgroupfile">AuthGroupFile</a></code> to
     work.</p>

    <p>For example:</p>

    <div class="example"><p><code>
      AuthName "Top Secret"
    </code></p></div>

     <p>The string provided for the <code>AuthName</code> is what will
     appear in the password dialog provided by most browsers.</p>

 <h3>See also</h3>
 <ul>
 <li><a href="../howto/auth.html">Authentication, Authorization, and
     Access Control</a></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="AuthType" id="AuthType">AuthType</a> <a name="authtype" id="authtype">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Type of user authentication</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AuthType Basic|Digest</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>This directive selects the type of user authentication for a
     directory. Only <code>Basic</code> and <code>Digest</code> are
     currently implemented.

      It must be accompanied by <code class="directive"><a href="#authname">AuthName</a></code> and <code class="directive"><a href="#require">Require</a></code> directives, and directives such
      as <code class="directive"><a href="../mod/mod_auth.html#authuserfile">AuthUserFile</a></code> and
      <code class="directive"><a href="../mod/mod_auth.html#authgroupfile">AuthGroupFile</a></code> to
      work.</p>

 <h3>See also</h3>
 <ul>
 <li><a href="../howto/auth.html">Authentication, Authorization,
 and Access Control</a></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="CGIMapExtension" id="CGIMapExtension">CGIMapExtension</a> <a name="cgimapextension" id="cgimapextension">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
 scripts</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CGIMapExtension <var>cgi-path</var> <var>.extension</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>NetWare only</td></tr>
 </table>
     <p>This directive is used to control how Apache finds the
     interpreter used to run CGI scripts. For example, setting
     <code>CGIMapExtension sys:\foo.nlm .foo</code> will
     cause all CGI script files with a <code>.foo</code> extension to
     be passed to the FOO interpreter.</p>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="ContentDigest" id="ContentDigest">ContentDigest</a> <a name="contentdigest" id="contentdigest">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables the generation of <code>Content-MD5</code> HTTP Response
 headers</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ContentDigest On|Off</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ContentDigest Off</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>This directive enables the generation of
     <code>Content-MD5</code> headers as defined in RFC1864
     respectively RFC2068.</p>

     <p>MD5 is an algorithm for computing a "message digest"
     (sometimes called "fingerprint") of arbitrary-length data, with
     a high degree of confidence that any alterations in the data
     will be reflected in alterations in the message digest.</p>

     <p>The <code>Content-MD5</code> header provides an end-to-end
     message integrity check (MIC) of the entity-body. A proxy or
     client may check this header for detecting accidental
     modification of the entity-body in transit. Example header:</p>

     <div class="example"><p><code>
       Content-MD5: AuLb7Dp1rqtRtxz2m9kRpA==
     </code></p></div>

     <p>Note that this can cause performance problems on your server
     since the message digest is computed on every request (the
     values are not cached).</p>

     <p><code>Content-MD5</code> is only sent for documents served
     by the <code class="module"><a href="../mod/core.html">core</a></code>, and not by any module. For example,
     SSI documents, output from CGI scripts, and byte range responses
     do not have this header.</p>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="DefaultType" id="DefaultType">DefaultType</a> <a name="defaulttype" id="defaulttype">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>MIME content-type that will be sent if the
 server cannot determine a type in any other way</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DefaultType <var>MIME-type</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DefaultType text/plain</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>There will be times when the server is asked to provide a
     document whose type cannot be determined by its MIME types
     mappings.</p>

     <p>The server must inform the client of the content-type of the
     document, so in the event of an unknown type it uses the
     <code>DefaultType</code>. For example:</p>

     <div class="example"><p><code>
       DefaultType image/gif
     </code></p></div>

     <p>would be appropriate for a directory which contained many GIF
     images with filenames missing the <code>.gif</code> extension.</p>

     <p>Note that unlike <code class="directive"><a href="#forcetype">ForceType</a></code>, this directive only
     provides the default mime-type. All other mime-type definitions,
     including filename extensions, that might identify the media type
     will override this default.</p>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="Directory" id="Directory">&lt;Directory&gt;</a> <a name="directory" id="directory">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose a group of directives that apply only to the
 named file-system directory and sub-directories</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>&lt;Directory <var>directory-path</var>&gt;
 ... &lt;/Directory&gt;</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p><code class="directive">&lt;Directory&gt;</code> and
     <code>&lt;/Directory&gt;</code> are used to enclose a group of
     directives that will apply only to the named directory and
     sub-directories of that directory. Any directive that is allowed
     in a directory context may be used. <var>Directory-path</var> is
     either the full path to a directory, or a wild-card string using
     Unix shell-style matching. In a wild-card string, <code>?</code> matches
     any single character, and <code>*</code> matches any sequences of
     characters. You may also use <code>[]</code> character ranges. None
     of the wildcards match a `/' character, so <code>&lt;Directory
     /*/public_html&gt;</code> will not match
     <code>/home/user/public_html</code>, but <code>&lt;Directory
     /home/*/public_html&gt;</code> will match. Example:</p>

     <div class="example"><p><code>
       &lt;Directory /usr/local/httpd/htdocs&gt;<br />
       <span class="indent">
         Options Indexes FollowSymLinks<br />
       </span>
       &lt;/Directory&gt;
     </code></p></div>

     <div class="note">
       <p>Be careful with the <var>directory-path</var> arguments:
       They have to literally match the filesystem path which Apache uses
       to access the files. Directives applied to a particular
       <code>&lt;Directory&gt;</code> will not apply to files accessed from
       that same directory via a different path, such as via different symbolic
       links.</p>
     </div>

     <p>Extended regular
     expressions can also be used, with the addition of the
     <code>~</code> character. For example:</p>

     <div class="example"><p><code>
       &lt;Directory ~ "^/www/.*/[0-9]{3}"&gt;
     </code></p></div>

     <p>would match directories in <code>/www/</code> that consisted of
     three numbers.</p>

     <p>If multiple (non-regular expression) <code class="directive">&lt;Directory&gt;</code> sections
     match the directory (or one of its parents) containing a document,
     then the directives are applied in the order of shortest match
     first, interspersed with the directives from the <a href="#accessfilename">.htaccess</a> files. For example,
     with</p>

     <div class="example"><p><code>
       &lt;Directory /&gt;<br />
       <span class="indent">
         AllowOverride None<br />
       </span>
       &lt;/Directory&gt;<br />
       <br />
       &lt;Directory /home/&gt;<br />
       <span class="indent">
         AllowOverride FileInfo<br />
       </span>
       &lt;/Directory&gt;
     </code></p></div>

     <p>for access to the document <code>/home/web/dir/doc.html</code>
     the steps are:</p>

     <ul>
       <li>Apply directive <code>AllowOverride None</code>
       (disabling <code>.htaccess</code> files).</li>

       <li>Apply directive <code>AllowOverride FileInfo</code> (for
       directory <code>/home</code>).</li>

       <li>Apply any <code>FileInfo</code> directives in
       <code>/home/.htaccess</code>, <code>/home/web/.htaccess</code> and
       <code>/home/web/dir/.htaccess</code> in that order.</li>
     </ul>

     <p>Regular expressions are not considered until after all of the
     normal sections have been applied. Then all of the regular
     expressions are tested in the order they appeared in the
     configuration file. For example, with</p>

     <div class="example"><p><code>
       &lt;Directory ~ abc$&gt;<br />
       <span class="indent">
         # ... directives here ...<br />
       </span>
       &lt;/Directory&gt;
     </code></p></div>

     <p>the regular expression section won't be considered until after
     all normal <code class="directive">&lt;Directory&gt;</code>s and
     <code>.htaccess</code> files have been applied. Then the regular
     expression will match on <code>/home/abc/public_html/abc</code> and
     the corresponding <code class="directive">&lt;Directory&gt;</code> will
     be applied.</p>

    <p><strong>Note that the default Apache access for
     <code>&lt;Directory /&gt;</code> is <code>Allow from All</code>.
     This means that Apache will serve any file mapped from an URL. It is
     recommended that you change this with a block such
     as</strong></p>

     <div class="example"><p><code>
       &lt;Directory /&gt;<br />
       <span class="indent">
         Order Deny,Allow<br />
         Deny from All<br />
       </span>
       &lt;/Directory&gt;
     </code></p></div>

     <p><strong>and then override this for directories you
     <em>want</em> accessible. See the <a href="../misc/security_tips.html">Security Tips</a> page for more
     details.</strong></p>

     <p>The directory sections occur in the <code>httpd.conf</code> file.
     <code class="directive">&lt;Directory&gt;</code> directives
     cannot nest, and cannot appear in a <code class="directive"><a href="#limit">&lt;Limit&gt;</a></code> or <code class="directive"><a href="#limitexcept">&lt;LimitExcept&gt;</a></code> section.</p>

 <h3>See also</h3>
 <ul>
 <li><a href="../sections.html">How &lt;Directory&gt;,
     &lt;Location&gt; and &lt;Files&gt; sections work</a> for an
     explanation of how these different sections are combined when a
     request is received</li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="DirectoryMatch" id="DirectoryMatch">&lt;DirectoryMatch&gt;</a> <a name="directorymatch" id="directorymatch">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enclose directives that apply to
 file-system directories matching a regular expression and their
 subdirectories</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>&lt;DirectoryMatch <var>regex</var>&gt;
 ... &lt;/DirectoryMatch&gt;</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p><code class="directive">&lt;DirectoryMatch&gt;</code> and
     <code>&lt;/DirectoryMatch&gt;</code> are used to enclose a group
     of directives which will apply only to the named directory and
     sub-directories of that directory, the same as <code class="directive"><a href="#directory">&lt;Directory&gt;</a></code>. However, it
     takes as an argument a regular expression. For example:</p>

     <div class="example"><p><code>
       &lt;DirectoryMatch "^/www/(.+/)?[0-9]{3}"&gt;
     </code></p></div>

     <p>would match directories in <code>/www/</code> that consisted of three
     numbers.</p>

 <h3>See also</h3>
 <ul>
 <li><code class="directive"><a href="#directory">&lt;Directory&gt;</a></code> for
 a description of how regular expressions are mixed in with normal
 <code class="directive">&lt;Directory&gt;</code>s</li>
 <li><a href="../sections.html">How &lt;Directory&gt;, &lt;Location&gt; and
 &lt;Files&gt; sections work</a> for an explanation of how these different
 sections are combined when a request is received</li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="DocumentRoot" id="DocumentRoot">DocumentRoot</a> <a name="documentroot" id="documentroot">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory that forms the main document tree visible
 from the web</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DocumentRoot <var>directory-path</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DocumentRoot /usr/local/apache/htdocs</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>This directive sets the directory from which <code class="program"><a href="../programs/httpd.html">httpd</a></code>
     will serve files. Unless matched by a directive like <code class="directive"><a href="../mod/mod_alias.html#alias">Alias</a></code>, the server appends the
     path from the requested URL to the document root to make the
     path to the document. Example:</p>

     <div class="example"><p><code>
       DocumentRoot /usr/web
     </code></p></div>

     <p>then an access to
     <code>http://www.my.host.com/index.html</code> refers to
     <code>/usr/web/index.html</code>.</p>

     <p>The <code class="directive">DocumentRoot</code> should be specified without
     a trailing slash.</p>

 <h3>See also</h3>
 <ul>
 <li><a href="../urlmapping.html">Mapping URLs to Filesystem
 Location</a></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="EnableMMAP" id="EnableMMAP">EnableMMAP</a> <a name="enablemmap" id="enablemmap">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use memory-mapping to read files during delivery</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableMMAP On|Off</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableMMAP On</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>This directive controls whether the <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use
     memory-mapping if it needs to read the contents of a file during
     delivery.  By default, when the handling of a request requires
     access to the data within a file -- for example, when delivering a
     server-parsed file using <code class="module"><a href="../mod/mod_include.html">mod_include</a></code> -- Apache
     memory-maps the file if the OS supports it.</p>

     <p>This memory-mapping sometimes yields a performance improvement.
     But in some environments, it is better to disable the memory-mapping
     to prevent operational problems:</p>

     <ul>
     <li>On some multiprocessor systems, memory-mapping can reduce the
     performance of the <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</li>
     <li>With an NFS-mounted <code class="directive"><a href="#documentroot">DocumentRoot</a></code>,
     the <code class="program"><a href="../programs/httpd.html">httpd</a></code> may crash due to a segmentation fault if a file
     is deleted or truncated while the <code class="program"><a href="../programs/httpd.html">httpd</a></code> has it
     memory-mapped.</li>
     </ul>

     <p>For server configurations that are vulnerable to these problems,
     you should disable memory-mapping of delivered files by specifying:</p>

     <div class="example"><p><code>
       EnableMMAP Off
     </code></p></div>

     <p>For NFS mounted files, this feature may be disabled explicitly for
     the offending files by specifying:</p>

     <div class="example"><p><code>
       &lt;Directory "/path-to-nfs-files"&gt;
       <span class="indent">
         EnableMMAP Off
       </span>
       &lt;/Directory&gt;
     </code></p></div>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="EnableSendfile" id="EnableSendfile">EnableSendfile</a> <a name="enablesendfile" id="enablesendfile">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use the kernel sendfile support to deliver files to the client</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableSendfile On|Off</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableSendfile On</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in version 2.0.44 and later</td></tr>
 </table>
     <p>This directive controls whether <code class="program"><a href="../programs/httpd.html">httpd</a></code> may use the
     sendfile support from the kernel to transmit file contents to the client.
     By default, when the handling of a request requires no access
     to the data within a file -- for example, when delivering a
     static file -- Apache uses sendfile to deliver the file contents
     without ever reading the file if the OS supports it.</p>

     <p>This sendfile mechanism avoids separate read and send operations,
     and buffer allocations. But on some platforms or within some
     filesystems, it is better to disable this feature to avoid
     operational problems:</p>

     <ul>
     <li>Some platforms may have broken sendfile support that the build
     system did not detect, especially if the binaries were built on
     another box and moved to such a machine with broken sendfile
     support.</li>
     <li>On Linux the use of sendfile triggers TCP-checksum
     offloading bugs on certain networking cards when using IPv6.</li>
     <li>With a network-mounted <code class="directive"><a href="#documentroot">DocumentRoot</a></code> (e.g., NFS or SMB),
     the kernel may be unable to serve the network file through
     its own cache.</li>
     </ul>

     <p>For server configurations that are vulnerable to these problems,
     you should disable this feature by specifying:</p>

     <div class="example"><p><code>
       EnableSendfile Off
     </code></p></div>

     <p>For NFS or SMB mounted files, this feature may be disabled explicitly
     for the offending files by specifying:</p>

     <div class="example"><p><code>
       &lt;Directory "/path-to-nfs-files"&gt;
       <span class="indent">
         EnableSendfile Off
       </span>
       &lt;/Directory&gt;
     </code></p></div>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="ErrorDocument" id="ErrorDocument">ErrorDocument</a> <a name="errordocument" id="errordocument">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>What the server will return to the client
 in case of an error</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ErrorDocument <var>error-code</var> <var>document</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Quoting syntax for text messages is different in Apache
 2.0</td></tr>
 </table>
     <p>In the event of a problem or error, Apache can be configured
     to do one of four things,</p>

     <ol>
       <li>output a simple hardcoded error message</li>

       <li>output a customized message</li>

       <li>redirect to a local <var>URL-path</var> to handle the
       problem/error</li>

       <li>redirect to an external <var>URL</var> to handle the
       problem/error</li>
     </ol>

     <p>The first option is the default, while options 2-4 are
     configured using the <code class="directive">ErrorDocument</code>
     directive, which is followed by the HTTP response code and a URL
     or a message. Apache will sometimes offer additional information
     regarding the problem/error.</p>

     <p>URLs can begin with a slash (/) for local web-paths (relative
     to the <code class="directive"><a href="#documentroot">DocumentRoot</a></code>), or be a
     full URL which the client can resolve. Alternatively, a message
     can be provided to be displayed by the browser. Examples:</p>

     <div class="example"><p><code>
       ErrorDocument 500 http://foo.example.com/cgi-bin/tester<br />
       ErrorDocument 404 /cgi-bin/bad_urls.pl<br />
       ErrorDocument 401 /subscription_info.html<br />
       ErrorDocument 403 "Sorry can't allow you access today"
     </code></p></div>

     <p>Additionally, the special value <code>default</code> can be used
     to specify Apache's simple hardcoded message.  While not required
     under normal circumstances, <code>default</code> will restore
     Apache's simple hardcoded message for configurations that would
     otherwise inherit an existing <code class="directive">ErrorDocument</code>.</p>

     <div class="example"><p><code>
       ErrorDocument 404 /cgi-bin/bad_urls.pl<br /><br />
       &lt;Directory /web/docs&gt;<br />
       <span class="indent">
         ErrorDocument 404 default<br />
       </span>
       &lt;/Directory&gt;
     </code></p></div>

     <p>Note that when you specify an <code class="directive">ErrorDocument</code>
     that points to a remote URL (ie. anything with a method such as
     <code>http</code> in front of it), Apache will send a redirect to the
     client to tell it where to find the document, even if the
     document ends up being on the same server. This has several
     implications, the most important being that the client will not
     receive the original error status code, but instead will
     receive a redirect status code. This in turn can confuse web
     robots and other clients which try to determine if a URL is
     valid using the status code. In addition, if you use a remote
     URL in an <code>ErrorDocument 401</code>, the client will not
     know to prompt the user for a password since it will not
     receive the 401 status code. Therefore, <strong>if you use an
     <code>ErrorDocument 401</code> directive then it must refer to a local
     document.</strong></p>

     <p>Microsoft Internet Explorer (MSIE) will by default ignore
     server-generated error messages when they are "too small" and substitute
     its own "friendly" error messages. The size threshold varies depending on
     the type of error, but in general, if you make your error document
     greater than 512 bytes, then MSIE will show the server-generated
     error rather than masking it.  More information is available in
     Microsoft Knowledge Base article <a href="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q294807">Q294807</a>.</p>

     <p>Although most error messages can be overriden, there are certain
     circumstances where the internal messages are used regardless of the
     setting of <code class="directive"><a href="#errordocument">ErrorDocument</a></code>.  In
     particular, if a malformed request is detected, normal request processing
     will be immediately halted and the internal error message returned.
     This is necessary to guard against security problems caused by
     bad requests.</p>

     <p>If you are using mod_proxy, you may wish to enable
     <code class="directive"><a href="../mod/mod_proxy.html#proxyerroroverride">ProxyErrorOverride</a></code> so that you can provide
     custom error messages on behalf of your Origin servers. If you don't enable ProxyErrorOverride,
     Apache will not generate custom error documents for proxied content.</p>

     <p>Prior to version 2.0, messages were indicated by prefixing
     them with a single unmatched double quote character.</p>

 <h3>See also</h3>
 <ul>
 <li><a href="../custom-error.html">documentation of
     customizable responses</a></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="ErrorLog" id="ErrorLog">ErrorLog</a> <a name="errorlog" id="errorlog">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Location where the server will log errors</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code> ErrorLog <var>file-path</var>|syslog[:<var>facility</var>]</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ErrorLog logs/error_log (Unix) ErrorLog logs/error.log (Windows and OS/2)</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>The <code class="directive">ErrorLog</code> directive sets the name of
     the file to which the server will log any errors it encounters. If
     the <var>file-path</var> is not absolute then it is assumed to be
     relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></code>.</p>

     <div class="example"><h3>Example</h3><p><code>
     ErrorLog /var/log/httpd/error_log
     </code></p></div>

     <p>If the <var>file-path</var>
     begins with a pipe (|) then it is assumed to be a command to spawn
     to handle the error log.</p>

     <div class="example"><h3>Example</h3><p><code>
     ErrorLog "|/usr/local/bin/httpd_errors"
     </code></p></div>

     <p>Using <code>syslog</code> instead of a filename enables logging
     via syslogd(8) if the system supports it. The default is to use
     syslog facility <code>local7</code>, but you can override this by
     using the <code>syslog:<var>facility</var></code> syntax where
     <var>facility</var> can be one of the names usually documented in
     syslog(1).</p>

     <div class="example"><h3>Example</h3><p><code>
     ErrorLog syslog:user
     </code></p></div>

     <p>SECURITY: See the <a href="../misc/security_tips.html#serverroot">security tips</a>
     document for details on why your security could be compromised
     if the directory where log files are stored is writable by
     anyone other than the user that starts the server.</p>
     <div class="warning"><h3>Note</h3>
       <p>When entering a file path on non-Unix platforms, care should be taken
       to make sure that only forward slashed are used even though the platform
       may allow the use of back slashes. In general it is a good idea to always
       use forward slashes throughout the configuration files.</p>
     </div>

 <h3>See also</h3>
 <ul>
 <li><code class="directive"><a href="#loglevel">LogLevel</a></code></li>
 <li><a href="../logs.html">Apache Log Files</a></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="FileETag" id="FileETag">FileETag</a> <a name="fileetag" id="fileetag">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>File attributes used to create the ETag
 HTTP response header</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>FileETag <var>component</var> ...</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>FileETag INode MTime Size</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>
     The <code class="directive">FileETag</code> directive configures the file
     attributes that are used to create the <code>ETag</code> (entity
     tag) response header field when the document is based on a file.
     (The <code>ETag</code> value is used in cache management to save
     network bandwidth.) In Apache 1.3.22 and earlier, the
     <code>ETag</code> value was <em>always</em> formed
     from the file's inode, size, and last-modified time (mtime). The
     <code class="directive">FileETag</code> directive allows you to choose
     which of these -- if any -- should be used. The recognized keywords are:
     </p>

     <dl>
      <dt><strong>INode</strong></dt>
      <dd>The file's i-node number will be included in the calculation</dd>
      <dt><strong>MTime</strong></dt>
      <dd>The date and time the file was last modified will be included</dd>
      <dt><strong>Size</strong></dt>
      <dd>The number of bytes in the file will be included</dd>
      <dt><strong>All</strong></dt>
      <dd>All available fields will be used. This is equivalent to:
          <div class="example"><p><code>FileETag INode MTime Size</code></p></div></dd>
      <dt><strong>None</strong></dt>
      <dd>If a document is file-based, no <code>ETag</code> field will be
        included in the response</dd>
     </dl>

     <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
     keywords may be prefixed with either <code>+</code> or <code>-</code>,
     which allow changes to be made to the default setting inherited
     from a broader scope. Any keyword appearing without such a prefix
     immediately and completely cancels the inherited setting.</p>

     <p>If a directory's configuration includes
     <code>FileETag&nbsp;INode&nbsp;MTime&nbsp;Size</code>, and a
     subdirectory's includes <code>FileETag&nbsp;-INode</code>,
     the setting for that subdirectory (which will be inherited by
     any sub-subdirectories that don't override it) will be equivalent to
     <code>FileETag&nbsp;MTime&nbsp;Size</code>.</p>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="Files" id="Files">&lt;Files&gt;</a> <a name="files" id="files">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to matched
 filenames</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>&lt;Files <var>filename</var>&gt; ... &lt;/Files&gt;</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>The <code class="directive">&lt;Files&gt;</code> directive
     limits the scope of the enclosed directives by filename. It is comparable
     to the <code class="directive"><a href="#directory">&lt;Directory&gt;</a></code>
     and <code class="directive"><a href="#location">&lt;Location&gt;</a></code>
     directives. It should be matched with a <code>&lt;/Files&gt;</code>
     directive. The directives given within this section will be applied to
     any object with a basename (last component of filename) matching the
     specified filename. <code class="directive">&lt;Files&gt;</code>
     sections are processed in the order they appear in the
     configuration file, after the <code class="directive"><a href="#directory">&lt;Directory&gt;</a></code> sections and
     <code>.htaccess</code> files are read, but before <code class="directive"><a href="#location">&lt;Location&gt;</a></code> sections. Note
     that <code class="directive">&lt;Files&gt;</code> can be nested
     inside <code class="directive"><a href="#directory">&lt;Directory&gt;</a></code> sections to restrict the
     portion of the filesystem they apply to.</p>

     <p>The <var>filename</var> argument should include a filename, or
     a wild-card string, where <code>?</code> matches any single character,
     and <code>*</code> matches any sequences of characters. Extended regular
     expressions can also be used, with the addition of the
     <code>~</code> character. For example:</p>

     <div class="example"><p><code>
       &lt;Files ~ "\.(gif|jpe?g|png)$"&gt;
     </code></p></div>

     <p>would match most common Internet graphics formats. <code class="directive"><a href="#filesmatch">&lt;FilesMatch&gt;</a></code> is preferred,
     however.</p>

     <p>Note that unlike <code class="directive"><a href="#directory">&lt;Directory&gt;</a></code> and <code class="directive"><a href="#location">&lt;Location&gt;</a></code> sections, <code class="directive">&lt;Files&gt;</code> sections can be used inside
     <code>.htaccess</code> files. This allows users to control access to
     their own files, at a file-by-file level.</p>


 <h3>See also</h3>
 <ul>
 <li><a href="../sections.html">How &lt;Directory&gt;, &lt;Location&gt;
     and &lt;Files&gt; sections work</a> for an explanation of how these
     different sections are combined when a request is received</li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="FilesMatch" id="FilesMatch">&lt;FilesMatch&gt;</a> <a name="filesmatch" id="filesmatch">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply to regular-expression matched
 filenames</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>&lt;FilesMatch <var>regex</var>&gt; ... &lt;/FilesMatch&gt;</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>The <code class="directive">&lt;FilesMatch&gt;</code> directive
     limits the scope of the enclosed directives by filename, just as the
     <code class="directive"><a href="#files">&lt;Files&gt;</a></code> directive
     does. However, it accepts a regular expression. For example:</p>

     <div class="example"><p><code>
       &lt;FilesMatch "\.(gif|jpe?g|png)$"&gt;
     </code></p></div>

     <p>would match most common Internet graphics formats.</p>

 <h3>See also</h3>
 <ul>
 <li><a href="../sections.html">How &lt;Directory&gt;, &lt;Location&gt;
     and &lt;Files&gt; sections work</a> for an explanation of how these
     different sections are combined when a request is received</li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="ForceType" id="ForceType">ForceType</a> <a name="forcetype" id="forcetype">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be served with the specified
 MIME content-type</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ForceType <var>MIME-type</var>|None</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Moved to the core in Apache 2.0</td></tr>
 </table>
     <p>When placed into an <code>.htaccess</code> file or a
     <code class="directive"><a href="#directory">&lt;Directory&gt;</a></code>, or
     <code class="directive"><a href="#location">&lt;Location&gt;</a></code> or
     <code class="directive"><a href="#files">&lt;Files&gt;</a></code>
     section, this directive forces all matching files to be served
     with the content type identification given by
     <var>MIME-type</var>. For example, if you had a directory full of
     GIF files, but did not want to label them all with <code>.gif</code>,
     you might want to use:</p>

     <div class="example"><p><code>
       ForceType image/gif
     </code></p></div>

     <p>Note that unlike <code class="directive"><a href="#defaulttype">DefaultType</a></code>,
     this directive overrides all mime-type associations, including
     filename extensions, that might identify the media type.</p>

     <p>You can override any <code class="directive">ForceType</code> setting
     by using the value of <code>None</code>:</p>

     <div class="example"><p><code>
       # force all files to be image/gif:<br />
       &lt;Location /images&gt;<br />
         <span class="indent">
           ForceType image/gif<br />
         </span>
       &lt;/Location&gt;<br />
       <br />
       # but normal mime-type associations here:<br />
       &lt;Location /images/mixed&gt;<br />
       <span class="indent">
         ForceType None<br />
       </span>
       &lt;/Location&gt;
     </code></p></div>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="HostnameLookups" id="HostnameLookups">HostnameLookups</a> <a name="hostnamelookups" id="hostnamelookups">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables DNS lookups on client IP addresses</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>HostnameLookups On|Off|Double</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>HostnameLookups Off</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>This directive enables DNS lookups so that host names can be
     logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
     The value <code>Double</code> refers to doing double-reverse
     DNS lookup. That is, after a reverse lookup is performed, a forward
     lookup is then performed on that result. At least one of the IP
     addresses in the forward lookup must match the original
     address. (In "tcpwrappers" terminology this is called
     <code>PARANOID</code>.)</p>

     <p>Regardless of the setting, when <code class="module"><a href="../mod/mod_access.html">mod_access</a></code> is
     used for controlling access by hostname, a double reverse lookup
     will be performed.  This is necessary for security. Note that the
     result of this double-reverse isn't generally available unless you
     set <code>HostnameLookups Double</code>. For example, if only
     <code>HostnameLookups On</code> and a request is made to an object
     that is protected by hostname restrictions, regardless of whether
     the double-reverse fails or not, CGIs will still be passed the
     single-reverse result in <code>REMOTE_HOST</code>.</p>

     <p>The default is <code>Off</code> in order to save the network
     traffic for those sites that don't truly need the reverse
     lookups done. It is also better for the end users because they
     don't have to suffer the extra latency that a lookup entails.
     Heavily loaded sites should leave this directive
     <code>Off</code>, since DNS lookups can take considerable
     amounts of time. The utility <code class="program"><a href="../programs/logresolve.html">logresolve</a></code>, compiled by
     default to the <code>bin</code> subdirectory of your installation
     directory, can be used to look up host names from logged IP addresses
     offline.</p>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="IdentityCheck" id="IdentityCheck">IdentityCheck</a> <a name="identitycheck" id="identitycheck">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables logging of the RFC1413 identity of the remote
 user</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>IdentityCheck On|Off</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>IdentityCheck Off</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>This directive enables RFC1413-compliant logging of the
     remote user name for each connection, where the client machine
     runs identd or something similar. This information is logged in
     the access log.</p>

     <p>The information should not be trusted in any way except for
     rudimentary usage tracking.</p>

     <p>Note that this can cause serious latency problems accessing
     your server since every request requires one of these lookups
     to be performed. When firewalls are involved each lookup might
     possibly fail and add 30 seconds of latency to each hit. So in
     general this is not very useful on public servers accessible
     from the Internet.</p>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="IfDefine" id="IfDefine">&lt;IfDefine&gt;</a> <a name="ifdefine" id="ifdefine">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that will be processed only
 if a test is true at startup</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>&lt;IfDefine [!]<var>parameter-name</var>&gt; ...
     &lt;/IfDefine&gt;</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>The <code>&lt;IfDefine <var>test</var>&gt;...&lt;/IfDefine&gt;
     </code> section is used to mark directives that are conditional. The
     directives within an <code class="directive">&lt;IfDefine&gt;</code>
     section are only processed if the <var>test</var> is true. If <var>
     test</var> is false, everything between the start and end markers is
     ignored.</p>

     <p>The <var>test</var> in the <code class="directive">&lt;IfDefine&gt;</code> section directive can be one of two forms:</p>

     <ul>
       <li><var>parameter-name</var></li>

       <li><code>!</code><var>parameter-name</var></li>
     </ul>

     <p>In the former case, the directives between the start and end
     markers are only processed if the parameter named
     <var>parameter-name</var> is defined. The second format reverses
     the test, and only processes the directives if
     <var>parameter-name</var> is <strong>not</strong> defined.</p>

     <p>The <var>parameter-name</var> argument is a define as given on
     the <code class="program"><a href="../programs/httpd.html">httpd</a></code> command line via <code>-D<var>parameter-</var>
     </code>, at the time the server was started.</p>

     <p><code class="directive">&lt;IfDefine&gt;</code> sections are
     nest-able, which can be used to implement simple
     multiple-parameter tests. Example:</p>

     <div class="example"><p><code>
       httpd -DReverseProxy ...<br />
       <br />
       # httpd.conf<br />
       &lt;IfDefine ReverseProxy&gt;<br />
       <span class="indent">
         LoadModule rewrite_module modules/mod_rewrite.so<br />
         LoadModule proxy_module   modules/libproxy.so<br />
       </span>
       &lt;/IfDefine&gt;
     </code></p></div>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="IfModule" id="IfModule">&lt;IfModule&gt;</a> <a name="ifmodule" id="ifmodule">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Encloses directives that are processed conditional on the
 presence or absence of a specific module</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>&lt;IfModule [!]<var>module-name</var>&gt; ...
     &lt;/IfModule&gt;</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>The <code>&lt;IfModule <var>test</var>&gt;...&lt;/IfModule&gt;</code>
     section is used to mark directives that are conditional on the presence of
     a specific module. The directives within an <code class="directive">&lt;IfModule&gt;</code> section are only processed if the <var>test</var>
     is true. If <var>test</var> is false, everything between the start and
     end markers is ignored.</p>

     <p>The <var>test</var> in the <code class="directive">&lt;IfModule&gt;</code> section directive can be one of two forms:</p>

     <ul>
       <li><var>module name</var></li>

       <li>!<var>module name</var></li>
     </ul>

     <p>In the former case, the directives between the start and end
     markers are only processed if the module named <var>module
     name</var> is included in Apache -- either compiled in or
     dynamically loaded using <code class="directive"><a href="../mod/mod_so.html#loadmodule">LoadModule</a></code>. The second format reverses the test,
     and only processes the directives if <var>module name</var> is
     <strong>not</strong> included.</p>

     <p>The <var>module name</var> argument is the file name of the
     module, at the time it was compiled.  For example,
     <code>mod_rewrite.c</code>.  If a module consists of several
     source files, use the name of the file containing the string
     <code>STANDARD20_MODULE_STUFF</code>.</p>

     <p><code class="directive">&lt;IfModule&gt;</code> sections are
     nest-able, which can be used to implement simple multiple-module
     tests.</p>

     <div class="note">This section should only be used if you need to have one
     configuration file that works whether or not a specific module
     is available. In normal operation, directives need not be
     placed in <code class="directive">&lt;IfModule&gt;</code>
     sections.</div>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="Include" id="Include">Include</a> <a name="include" id="include">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Includes other configuration files from within
 the server configuration files</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Include <var>file-path</var>|<var>directory-path</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Wildcard matching available in 2.0.41 and later</td></tr>
 </table>
     <p>This directive allows inclusion of other configuration files
     from within the server configuration files.</p>

     <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used to
     include several files at once, in alphabetical order. In
     addition, if <code class="directive">Include</code> points to a directory,
     rather than a file, Apache will read all files in that directory
     and any subdirectory.  But including entire directories is not
     recommended, because it is easy to accidentally leave temporary
     files in a directory that can cause <code class="program"><a href="../programs/httpd.html">httpd</a></code> to
     fail.</p>

     <p>The file path specified may be an absolute path, or may be relative
     to the <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory.</p>

     <p>Examples:</p>

     <div class="example"><p><code>
       Include /usr/local/apache2/conf/ssl.conf<br />
       Include /usr/local/apache2/conf/vhosts/*.conf
     </code></p></div>

     <p>Or, providing paths relative to your <code class="directive"><a href="#serverroot">ServerRoot</a></code> directory:</p>

     <div class="example"><p><code>
       Include conf/ssl.conf<br />
       Include conf/vhosts/*.conf
     </code></p></div>

 <h3>See also</h3>
 <ul>
 <li><code class="program"><a href="../programs/apachectl.html">apachectl</a></code></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="KeepAlive" id="KeepAlive">KeepAlive</a> <a name="keepalive" id="keepalive">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables HTTP persistent connections</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAlive On|Off</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAlive On</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>The Keep-Alive extension to HTTP/1.0 and the persistent
     connection feature of HTTP/1.1 provide long-lived HTTP sessions
     which allow multiple requests to be sent over the same TCP
     connection. In some cases this has been shown to result in an
     almost 50% speedup in latency times for HTML documents with
     many images. To enable Keep-Alive connections, set
     <code>KeepAlive On</code>.</p>

     <p>For HTTP/1.0 clients, Keep-Alive connections will only be
     used if they are specifically requested by a client. In
     addition, a Keep-Alive connection with an HTTP/1.0 client can
     only be used when the length of the content is known in
     advance. This implies that dynamic content such as CGI output,
     SSI pages, and server-generated directory listings will
     generally not use Keep-Alive connections to HTTP/1.0 clients.
     For HTTP/1.1 clients, persistent connections are the default
     unless otherwise specified. If the client requests it, chunked
     encoding will be used in order to send content of unknown
     length over persistent connections.</p>

 <h3>See also</h3>
 <ul>
 <li><code class="directive"><a href="#maxkeepaliverequests">MaxKeepAliveRequests</a></code></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="KeepAliveTimeout" id="KeepAliveTimeout">KeepAliveTimeout</a> <a name="keepalivetimeout" id="keepalivetimeout">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for subsequent
 requests on a persistent connection</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>KeepAliveTimeout <var>seconds</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>KeepAliveTimeout 15</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>The number of seconds Apache will wait for a subsequent
     request before closing the connection. Once a request has been
     received, the timeout value specified by the
     <code class="directive"><a href="#timeout">Timeout</a></code> directive applies.</p>

     <p>Setting <code class="directive">KeepAliveTimeout</code> to a high value
     may cause performance problems in heavily loaded servers. The
     higher the timeout, the more server processes will be kept
     occupied waiting on connections with idle clients.</p>

     <p>In a name-based virtual host context, the value of the first
     defined virtual host (the default host) in a set of <code class="directive"><a href="#namevirtualhost">NameVirtualHost</a></code> will be used.
     The other values will be ignored.</p>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="Limit" id="Limit">&lt;Limit&gt;</a> <a name="limit" id="limit">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict enclosed access controls to only certain HTTP
 methods</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>&lt;Limit <var>method</var> [<var>method</var>] ... &gt; ...
     &lt;/Limit&gt;</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>Access controls are normally effective for
     <strong>all</strong> access methods, and this is the usual
     desired behavior. <strong>In the general case, access control
     directives should not be placed within a
     <code class="directive">&lt;Limit&gt;</code> section.</strong></p>

     <p>The purpose of the <code class="directive">&lt;Limit&gt;</code>
     directive is to restrict the effect of the access controls to the
     nominated HTTP methods. For all other methods, the access
     restrictions that are enclosed in the <code class="directive">&lt;Limit&gt;</code> bracket <strong>will have no
     effect</strong>. The following example applies the access control
     only to the methods <code>POST</code>, <code>PUT</code>, and
     <code>DELETE</code>, leaving all other methods unprotected:</p>

     <div class="example"><p><code>
       &lt;Limit POST PUT DELETE&gt;<br />
       <span class="indent">
         Require valid-user<br />
       </span>
       &lt;/Limit&gt;
     </code></p></div>

     <p>The method names listed can be one or more of: <code>GET</code>,
     <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
     <code>CONNECT</code>, <code>OPTIONS</code>,
     <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
     <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
     <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
     case-sensitive.</strong> If <code>GET</code> is used it will also
     restrict <code>HEAD</code> requests. The <code>TRACE</code> method
     cannot be limited.</p>

     <div class="warning">A <code class="directive"><a href="#limitexcept">&lt;LimitExcept&gt;</a></code> section should always be
     used in preference to a <code class="directive"><a href="#limit">&lt;Limit&gt;</a></code> section when restricting access,
     since a <code class="directive"><a href="#limitexcept">&lt;LimitExcept&gt;</a></code> section provides protection
     against arbitrary methods.</div>


 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="LimitExcept" id="LimitExcept">&lt;LimitExcept&gt;</a> <a name="limitexcept" id="limitexcept">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restrict access controls to all HTTP methods
 except the named ones</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>&lt;LimitExcept <var>method</var> [<var>method</var>] ... &gt; ...
     &lt;/LimitExcept&gt;</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p><code class="directive">&lt;LimitExcept&gt;</code> and
     <code>&lt;/LimitExcept&gt;</code> are used to enclose
     a group of access control directives which will then apply to any
     HTTP access method <strong>not</strong> listed in the arguments;
     i.e., it is the opposite of a <code class="directive"><a href="#limit">&lt;Limit&gt;</a></code> section and can be used to control
     both standard and nonstandard/unrecognized methods. See the
     documentation for <code class="directive"><a href="#limit">&lt;Limit&gt;</a></code> for more details.</p>

     <p>For example:</p>

     <div class="example"><p><code>
       &lt;LimitExcept POST GET&gt;<br />
       <span class="indent">
         Require valid-user<br />
       </span>
       &lt;/LimitExcept&gt;
     </code></p></div>


 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="LimitInternalRecursion" id="LimitInternalRecursion">LimitInternalRecursion</a> <a name="limitinternalrecursion" id="limitinternalrecursion">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine maximum number of internal redirects and nested
 subrequests</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitInternalRecursion <var>number</var> [<var>number</var>]</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitInternalRecursion 10</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.0.47 and later</td></tr>
 </table>
     <p>An internal redirect happens, for example, when using the <code class="directive"><a href="../mod/mod_actions.html#action">Action</a></code> directive, which internally
     redirects the original request to a CGI script. A subrequest is Apache's
     mechanism to find out what would happen for some URI if it were requested.
     For example, <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> uses subrequests to look for the
     files listed in the <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
     directive.</p>

     <p><code class="directive">LimitInternalRecursion</code> prevents the server
     from crashing when entering an infinite loop of internal redirects or
     subrequests. Such loops are usually caused by misconfigurations.</p>

     <p>The directive stores two different limits, which are evaluated on
     per-request basis. The first <var>number</var> is the maximum number of
     internal redirects, that may follow each other. The second <var>number</var>
     determines, how deep subrequests may be nested. If you specify only one
     <var>number</var>, it will be assigned to both limits.</p>

     <div class="example"><h3>Example</h3><p><code>
       LimitInternalRecursion 5
     </code></p></div>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="LimitRequestBody" id="LimitRequestBody">LimitRequestBody</a> <a name="limitrequestbody" id="limitrequestbody">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Restricts the total size of the HTTP request body sent
 from the client</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestBody <var>bytes</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestBody 0</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>This directive specifies the number of <var>bytes</var> from 0
     (meaning unlimited) to 2147483647 (2GB) that are allowed in a
     request body.</p>

     <p>The <code class="directive">LimitRequestBody</code> directive allows
     the user to set a limit on the allowed size of an HTTP request
     message body within the context in which the directive is given
     (server, per-directory, per-file or per-location). If the client
     request exceeds that limit, the server will return an error
     response instead of servicing the request. The size of a normal
     request message body will vary greatly depending on the nature of
     the resource and the methods allowed on that resource. CGI scripts
     typically use the message body for retrieving form information.
     Implementations of the <code>PUT</code> method will require
     a value at least as large as any representation that the server
     wishes to accept for that resource.</p>

     <p>This directive gives the server administrator greater
     control over abnormal client request behavior, which may be
     useful for avoiding some forms of denial-of-service
     attacks.</p>

     <p>If, for example, you are permitting file upload to a particular
     location, and wish to limit the size of the uploaded file to 100K,
     you might use the following directive:</p>

     <div class="example"><p><code>
       LimitRequestBody 102400
     </code></p></div>


 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="LimitRequestFields" id="LimitRequestFields">LimitRequestFields</a> <a name="limitrequestfields" id="limitrequestfields">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of HTTP request header fields that
 will be accepted from the client</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFields <var>number</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFields 100</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p><var>Number</var> is an integer from 0 (meaning unlimited) to
     32767. The default value is defined by the compile-time
     constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
     distributed).</p>

     <p>The <code class="directive">LimitRequestFields</code> directive allows
     the server administrator to modify the limit on the number of
     request header fields allowed in an HTTP request. A server needs
     this value to be larger than the number of fields that a normal
     client request might include. The number of request header fields
     used by a client rarely exceeds 20, but this may vary among
     different client implementations, often depending upon the extent
     to which a user has configured their browser to support detailed
     content negotiation. Optional HTTP extensions are often expressed
     using request header fields.</p>

     <p>This directive gives the server administrator greater
     control over abnormal client request behavior, which may be
     useful for avoiding some forms of denial-of-service attacks.
     The value should be increased if normal clients see an error
     response from the server that indicates too many fields were
     sent in the request.</p>

     <p>For example:</p>

     <div class="example"><p><code>
       LimitRequestFields 50
     </code></p></div>

      <div class="warning"><h3>Warning</h3>
      <p> When name-based virtual hosting is used, the value for this
      directive is taken from the default (first-listed) virtual host for the
      <code class="directive">NameVirtualHost</code> the connection was mapped to.</p>
      </div>


 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="LimitRequestFieldSize" id="LimitRequestFieldSize">LimitRequestFieldSize</a> <a name="limitrequestfieldsize" id="limitrequestfieldsize">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of the HTTP request header allowed from the
 client</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestFieldsize <var>bytes</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestFieldsize 8190</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>This directive specifies the number of <var>bytes</var>
     that will be allowed in an HTTP request header.</p>

     <p>The <code class="directive">LimitRequestFieldSize</code> directive
     allows the server administrator to reduce or increase the limit
     on the allowed size of an HTTP request header field. A server
     needs this value to be large enough to hold any one header field
     from a normal client request. The size of a normal request header
     field will vary greatly among different client implementations,
     often depending upon the extent to which a user has configured
     their browser to support detailed content negotiation. SPNEGO
     authentication headers can be up to 12392 bytes.</p>

     <p>This directive gives the server administrator greater
     control over abnormal client request behavior, which may be
     useful for avoiding some forms of denial-of-service attacks.</p>

     <p>For example:</p>

     <div class="example"><p><code>
       LimitRequestFieldSize 4094
     </code></p></div>

     <div class="note">Under normal conditions, the value should not be changed from
     the default.</div>

     <div class="note">Apache 2.0.53 or higher is required for increasing the
     limit above the compiled-in value of DEFAULT_LIMIT_REQUEST_FIELDSIZE
     (8190 as distributed).
     </div>

      <div class="warning"><h3>Warning</h3>
      <p> When name-based virtual hosting is used, the value for this
      directive is taken from the default (first-listed) virtual host for the
      <code class="directive">NameVirtualHost</code> the connection was mapped to.</p>
      </div>


 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="LimitRequestLine" id="LimitRequestLine">LimitRequestLine</a> <a name="limitrequestline" id="limitrequestline">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limit the size of the HTTP request line that will be accepted
 from the client</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitRequestLine <var>bytes</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitRequestLine 8190</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>This directive sets the number of <var>bytes</var> from 0 to
     the value of the compile-time constant
     <code>DEFAULT_LIMIT_REQUEST_LINE</code> (8190 as distributed)
     that will be allowed on the HTTP request-line.</p>

     <p>The <code class="directive">LimitRequestLine</code> directive allows
     the server administrator to reduce the limit on the allowed size
     of a client's HTTP request-line below the normal input buffer size
     compiled with the server. Since the request-line consists of the
     HTTP method, URI, and protocol version, the
     <code class="directive">LimitRequestLine</code> directive places a
     restriction on the length of a request-URI allowed for a request
     on the server. A server needs this value to be large enough to
     hold any of its resource names, including any information that
     might be passed in the query part of a <code>GET</code> request.</p>

     <p>This directive gives the server administrator greater
     control over abnormal client request behavior, which may be
     useful for avoiding some forms of denial-of-service attacks.</p>

     <p>For example:</p>

     <div class="example"><p><code>
       LimitRequestLine 4094
     </code></p></div>

     <div class="note">Under normal conditions, the value should not be changed from
     the default.</div>

     <div class="warning"><h3>Warning</h3>
     <p> When name-based virtual hosting is used, the value for this
     directive is taken from the default (first-listed) virtual host for the
     <code class="directive">NameVirtualHost</code> the connection was mapped to.</p>
     </div>


 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="LimitXMLRequestBody" id="LimitXMLRequestBody">LimitXMLRequestBody</a> <a name="limitxmlrequestbody" id="limitxmlrequestbody">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the size of an XML-based request body</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitXMLRequestBody <var>bytes</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LimitXMLRequestBody 1000000</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>Limit (in bytes) on maximum size of an XML-based request
     body. A value of <code>0</code> will disable any checking.</p>

     <p>Example:</p>

     <div class="example"><p><code>
       LimitXMLRequestBody 0
     </code></p></div>


 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="Location" id="Location">&lt;Location&gt;</a> <a name="location" id="location">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to matching
 URLs</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>&lt;Location
     <var>URL-path</var>|<var>URL</var>&gt; ... &lt;/Location&gt;</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>The <code class="directive">&lt;Location&gt;</code> directive
     limits the scope of the enclosed directives by URL. It is similar to the
     <code class="directive"><a href="#directory">&lt;Directory&gt;</a></code>
     directive, and starts a subsection which is terminated with a
     <code>&lt;/Location&gt;</code> directive. <code class="directive">&lt;Location&gt;</code> sections are processed in the
     order they appear in the configuration file, after the <code class="directive"><a href="#directory">&lt;Directory&gt;</a></code> sections and
     <code>.htaccess</code> files are read, and after the <code class="directive"><a href="#files">&lt;Files&gt;</a></code> sections.</p>

     <p><code class="directive">&lt;Location&gt;</code> sections operate
     completely outside the filesystem.  This has several consequences.
     Most importantly, <code class="directive">&lt;Location&gt;</code>
     directives should not be used to control access to filesystem
     locations.  Since several different URLs may map to the same
     filesystem location, such access controls may by circumvented.</p>

     <div class="note"><h3>When to use <code class="directive">&lt;Location&gt;</code></h3>

     <p>Use <code class="directive">&lt;Location&gt;</code> to apply
     directives to content that lives outside the filesystem.  For
     content that lives in the filesystem, use <code class="directive"><a href="#directory">&lt;Directory&gt;</a></code> and <code class="directive"><a href="#files">&lt;Files&gt;</a></code>.  An exception is
     <code>&lt;Location /&gt;</code>, which is an easy way to
     apply a configuration to the entire server.</p>
     </div>

     <p>For all origin (non-proxy) requests, the URL to be matched is a
     URL-path of the form <code>/path/</code>.  No scheme, hostname,
     port, or query string may be included.  For proxy requests, the
     URL to be matched is of the form
     <code>scheme://servername/path</code>, and you must include the
     prefix.</p>

     <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
     any single character, and <code>*</code> matches any sequences of
     characters.</p>

     <p>Extended regular
     expressions can also be used, with the addition of the
     <code>~</code> character. For example:</p>

     <div class="example"><p><code>
       &lt;Location ~ "/(extra|special)/data"&gt;
     </code></p></div>

     <p>would match URLs that contained the substring <code>/extra/data</code>
     or <code>/special/data</code>. The directive <code class="directive"><a href="#locationmatch">&lt;LocationMatch&gt;</a></code> behaves
     identical to the regex version of <code class="directive">&lt;Location&gt;</code>.</p>

     <p>The <code class="directive">&lt;Location&gt;</code>
     functionality is especially useful when combined with the
     <code class="directive"><a href="#sethandler">SetHandler</a></code>
     directive. For example, to enable status requests, but allow them
     only from browsers at <code>foo.com</code>, you might use:</p>

     <div class="example"><p><code>
       &lt;Location /status&gt;<br />
       <span class="indent">
         SetHandler server-status<br />
         Order Deny,Allow<br />
         Deny from all<br />
         Allow from .foo.com<br />
       </span>
       &lt;/Location&gt;
     </code></p></div>

     <div class="note"><h3>Note about / (slash)</h3>
       <p>The slash character has special meaning depending on where in a
       URL it appears. People may be used to its behavior in the filesystem
       where multiple adjacent slashes are frequently collapsed to a single
       slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
       <code>/home/foo</code>). In URL-space this is not necessarily true.
       The <code class="directive"><a href="#locationmatch">&lt;LocationMatch&gt;</a></code>
       directive and the regex version of <code class="directive">&lt;Location&gt;</code> require you to explicitly specify multiple
       slashes if that is your intention.</p>

       <p>For example, <code>&lt;LocationMatch ^/abc&gt;</code> would match
       the request URL <code>/abc</code> but not the request URL <code>
       //abc</code>. The (non-regex) <code class="directive">&lt;Location&gt;</code> directive behaves similarly when used for
       proxy requests. But when (non-regex) <code class="directive">&lt;Location&gt;</code> is used for non-proxy requests it will
       implicitly match multiple slashes with a single slash. For example,
       if you specify <code>&lt;Location /abc/def&gt;</code> and the
       request is to <code>/abc//def</code> then it will match.</p>
     </div>

 <h3>See also</h3>
 <ul>
 <li><a href="../sections.html">How &lt;Directory&gt;, &lt;Location&gt;
     and &lt;Files&gt; sections work</a> for an explanation of how these
     different sections are combined when a request is received</li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="LocationMatch" id="LocationMatch">&lt;LocationMatch&gt;</a> <a name="locationmatch" id="locationmatch">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Applies the enclosed directives only to regular-expression
 matching URLs</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>&lt;LocationMatch
     <var>regex</var>&gt; ... &lt;/LocationMatch&gt;</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>The <code class="directive">&lt;LocationMatch&gt;</code> directive
     limits the scope of the enclosed directives by URL, in an identical manner
     to <code class="directive"><a href="#location">&lt;Location&gt;</a></code>. However,
     it takes a regular expression as an argument instead of a simple
     string. For example:</p>

     <div class="example"><p><code>
       &lt;LocationMatch "/(extra|special)/data"&gt;
     </code></p></div>

     <p>would match URLs that contained the substring <code>/extra/data</code>
     or <code>/special/data</code>.</p>

 <h3>See also</h3>
 <ul>
 <li><a href="../sections.html">How &lt;Directory&gt;, &lt;Location&gt;
     and &lt;Files&gt; sections work</a> for an explanation of how these
     different sections are combined when a request is received</li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="LogLevel" id="LogLevel">LogLevel</a> <a name="loglevel" id="loglevel">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Controls the verbosity of the ErrorLog</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LogLevel <var>level</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LogLevel warn</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p><code class="directive">LogLevel</code> adjusts the verbosity of the
     messages recorded in the error logs (see <code class="directive"><a href="#errorlog">ErrorLog</a></code> directive). The following
     <var>level</var>s are available, in order of decreasing
     significance:</p>

     <table class="bordered">

       <tr>
         <th><strong>Level</strong> </th>

         <th><strong>Description</strong> </th>

         <th><strong>Example</strong> </th>
       </tr>

       <tr>
         <td><code>emerg</code> </td>

         <td>Emergencies - system is unusable.</td>

         <td>"Child cannot open lock file. Exiting"</td>
       </tr>

       <tr>
         <td><code>alert</code> </td>

         <td>Action must be taken immediately.</td>

         <td>"getpwuid: couldn't determine user name from uid"</td>
       </tr>

       <tr>
         <td><code>crit</code> </td>

         <td>Critical Conditions.</td>

         <td>"socket: Failed to get a socket, exiting child"</td>
       </tr>

       <tr>
         <td><code>error</code> </td>

         <td>Error conditions.</td>

         <td>"Premature end of script headers"</td>
       </tr>

       <tr>
         <td><code>warn</code> </td>

         <td>Warning conditions.</td>

         <td>"child process 1234 did not exit, sending another
         SIGHUP"</td>
       </tr>

       <tr>
         <td><code>notice</code> </td>

         <td>Normal but significant condition.</td>

         <td>"httpd: caught SIGBUS, attempting to dump core in
         ..."</td>
       </tr>

       <tr>
         <td><code>info</code> </td>

         <td>Informational.</td>

         <td>"Server seems busy, (you may need to increase
         StartServers, or Min/MaxSpareServers)..."</td>
       </tr>

       <tr>
         <td><code>debug</code> </td>

         <td>Debug-level messages</td>

         <td>"Opening config file ..."</td>
       </tr>
     </table>

     <p>When a particular level is specified, messages from all
     other levels of higher significance will be reported as well.
     <em>E.g.</em>, when <code>LogLevel info</code> is specified,
     then messages with log levels of <code>notice</code> and
     <code>warn</code> will also be posted.</p>

     <p>Using a level of at least <code>crit</code> is
     recommended.</p>

     <p>For example:</p>

     <div class="example"><p><code>
       LogLevel notice
     </code></p></div>

     <div class="note"><h3>Note</h3>
       <p>When logging to a regular file messages of the level
       <code>notice</code> cannot be suppressed and thus are always
       logged. However, this doesn't apply when logging is done
       using <code>syslog</code>.</p>
     </div>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="MaxKeepAliveRequests" id="MaxKeepAliveRequests">MaxKeepAliveRequests</a> <a name="maxkeepaliverequests" id="maxkeepaliverequests">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of requests allowed on a persistent
 connection</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxKeepAliveRequests <var>number</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxKeepAliveRequests 100</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>The <code class="directive">MaxKeepAliveRequests</code> directive
     limits the number of requests allowed per connection when
     <code class="directive"><a href="#keepalive">KeepAlive</a></code> is on. If it is
     set to <code>0</code>, unlimited requests will be allowed. We
     recommend that this setting be kept to a high value for maximum
     server performance.</p>

     <p>For example:</p>

     <div class="example"><p><code>
       MaxKeepAliveRequests 500
     </code></p></div>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="MaxRanges" id="MaxRanges">MaxRanges</a> <a name="maxranges" id="maxranges">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of ranges allowed before returning the complete
 resource </td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxRanges default | unlimited | none | <var>number-of-ranges</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRanges 200</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.0.65 and later</td></tr>
 </table>
     <p>The <code class="directive">MaxRanges</code> directive
     limits the number of HTTP ranges the server is willing to
     return to the client.  If more ranges then permitted are requested,
     the complete resource is returned instead.</p>

     <dl>
       <dt><strong>default</strong></dt>
       <dd>Limits the number of ranges to a compile-time default of 200.</dd>

       <dt><strong>none</strong></dt>
       <dd>Range headers are ignored.</dd>

       <dt><strong>unlimited</strong></dt>
       <dd>The server does not limit the number of ranges it is
           willing to satisfy.</dd>

       <dt><var>number-of-ranges</var></dt>
       <dd>A positive number representing the maximum number of ranges the
       server is willing to satisfy.</dd>
     </dl>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="NameVirtualHost" id="NameVirtualHost">NameVirtualHost</a> <a name="namevirtualhost" id="namevirtualhost">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Designates an IP address for name-virtual
 hosting</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NameVirtualHost <var>addr</var>[:<var>port</var>]</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>The <code class="directive">NameVirtualHost</code> directive is a
     required directive if you want to configure <a href="../vhosts/">name-based virtual hosts</a>.</p>

     <p>Although <var>addr</var> can be hostname it is recommended
     that you always use an IP address, e.g.</p>

     <div class="example"><p><code>
       NameVirtualHost 111.22.33.44
     </code></p></div>

     <p>With the <code class="directive">NameVirtualHost</code> directive you
     specify the IP address on which the server will receive requests
     for the name-based virtual hosts. This will usually be the address
     to which your name-based virtual host names resolve. In cases
     where a firewall or other proxy receives the requests and forwards
     them on a different IP address to the server, you must specify the
     IP address of the physical interface on the machine which will be
     servicing the requests. If you have multiple name-based hosts on
     multiple addresses, repeat the directive for each address.</p>

     <div class="note"><h3>Note</h3>
       <p>Note, that the "main server" and any <code>_default_</code> servers
       will <strong>never</strong> be served for a request to a
       <code class="directive">NameVirtualHost</code> IP address (unless for some
       reason you specify <code class="directive">NameVirtualHost</code> but then
       don't define any <code class="directive">VirtualHost</code>s for that
       address).</p>
     </div>

     <p>Optionally you can specify a port number on which the
     name-based virtual hosts should be used, e.g.</p>

     <div class="example"><p><code>
       NameVirtualHost 111.22.33.44:8080
     </code></p></div>

     <p>IPv6 addresses must be enclosed in square brackets, as shown
     in the following example:</p>

     <div class="example"><p><code>
       NameVirtualHost [2001:db8::a00:20ff:fea7:ccea]:8080
     </code></p></div>

     <p>To receive requests on all interfaces, you can use an argument of
     <code>*</code></p>

     <div class="example"><p><code>
       NameVirtualHost *
     </code></p></div>

     <div class="note"><h3>Argument to <code class="directive">&lt;VirtualHost&gt;</code>
       directive</h3>
       <p>Note that the argument to the <code class="directive">&lt;VirtualHost&gt;</code> directive must
       exactly match the argument to the <code class="directive">NameVirtualHost</code> directive.</p>

       <div class="example"><p><code>
         NameVirtualHost 1.2.3.4<br />
         &lt;VirtualHost 1.2.3.4&gt;<br />
         # ...<br />
         &lt;/VirtualHost&gt;<br />
       </code></p></div>
     </div>

 <h3>See also</h3>
 <ul>
 <li><a href="../vhosts/">Virtual Hosts
 documentation</a></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="Options" id="Options">Options</a> <a name="options" id="options">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures what features are available in a particular
 directory</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Options
     [+|-]<var>option</var> [[+|-]<var>option</var>] ...</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Options All</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>Options</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>The <code class="directive">Options</code> directive controls which
     server features are available in a particular directory.</p>

     <p><var>option</var> can be set to <code>None</code>, in which
     case none of the extra features are enabled, or one or more of
     the following:</p>

     <dl>
       <dt><code>All</code></dt>

       <dd>All options except for <code>MultiViews</code>. This is the default
       setting.</dd>

       <dt><code>ExecCGI</code></dt>

       <dd>
       Execution of CGI scripts using <code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code>
       is permitted.</dd>

       <dt><code>FollowSymLinks</code></dt>

       <dd>

       The server will follow symbolic links in this directory.
       <div class="note">
       <p>Even though the server follows the symlink it does <em>not</em>
       change the pathname used to match against <code class="directive"><a href="#directory">&lt;Directory&gt;</a></code> sections.</p>
       <p>Note also, that this option <strong>gets ignored</strong> if set
       inside a <code class="directive"><a href="#location">&lt;Location&gt;</a></code>
       section.</p>
       </div></dd>

       <dt><code>Includes</code></dt>

       <dd>
       Server-side includes provided by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>
       are permitted.</dd>

       <dt><code>IncludesNOEXEC</code></dt>

       <dd>

       Server-side includes are permitted, but the <code>#exec
       cmd</code> and <code>#exec cgi</code> are disabled. It is still
       possible to <code>#include virtual</code> CGI scripts from
       <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>ed
       directories.</dd>

       <dt><code>Indexes</code></dt>

       <dd>
       If a URL which maps to a directory is requested, and there
       is no <code class="directive"><a href="../mod/mod_dir.html#directoryindex">DirectoryIndex</a></code>
       (<em>e.g.</em>, <code>index.html</code>) in that directory, then
       <code class="module"><a href="../mod/mod_autoindex.html">mod_autoindex</a></code> will return a formatted listing
       of the directory.</dd>

       <dt><code>MultiViews</code></dt>

       <dd>
       <a href="../content-negotiation.html">Content negotiated</a>
       "MultiViews" are allowed using
       <code class="module"><a href="../mod/mod_negotiation.html">mod_negotiation</a></code>.</dd>

       <dt><code>SymLinksIfOwnerMatch</code></dt>

       <dd>The server will only follow symbolic links for which the
       target file or directory is owned by the same user id as the
       link.

       <div class="note"><h3>Note</h3> This option gets ignored if
       set inside a <code class="directive"><a href="#location">&lt;Location&gt;</a></code> section.</div>
       </dd>
     </dl>

     <p>Normally, if multiple <code class="directive">Options</code> could
     apply to a directory, then the most specific one is used and
     others are ignored; the options are not merged. (See <a href="../sections.html#mergin">how sections are merged</a>.)
     However if <em>all</em> the options on the
     <code class="directive">Options</code> directive are preceded by a
     <code>+</code> or <code>-</code> symbol, the options are
     merged. Any options preceded by a <code>+</code> are added to the
     options currently in force, and any options preceded by a
     <code>-</code> are removed from the options currently in
     force. </p>

     <div class="warning"><h3>Warning</h3>
     <p>Mixing <code class="directive">Options</code> with a <code>+</code> or
     <code>-</code> with those without is not valid syntax, and is likely
     to cause unexpected results.</p>
     </div>

     <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>

     <div class="example"><p><code>
       &lt;Directory /web/docs&gt;<br />
       <span class="indent">
         Options Indexes FollowSymLinks<br />
       </span>
       &lt;/Directory&gt;<br />
       <br />
       &lt;Directory /web/docs/spec&gt;<br />
       <span class="indent">
         Options Includes<br />
       </span>
       &lt;/Directory&gt;
     </code></p></div>

     <p>then only <code>Includes</code> will be set for the
     <code>/web/docs/spec</code> directory. However if the second
     <code class="directive">Options</code> directive uses the <code>+</code> and
     <code>-</code> symbols:</p>

     <div class="example"><p><code>
       &lt;Directory /web/docs&gt;<br />
       <span class="indent">
         Options Indexes FollowSymLinks<br />
       </span>
       &lt;/Directory&gt;<br />
       <br />
       &lt;Directory /web/docs/spec&gt;<br />
       <span class="indent">
         Options +Includes -Indexes<br />
       </span>
       &lt;/Directory&gt;
     </code></p></div>

     <p>then the options <code>FollowSymLinks</code> and
     <code>Includes</code> are set for the <code>/web/docs/spec</code>
     directory.</p>

     <div class="note"><h3>Note</h3>
       <p>Using <code>-IncludesNOEXEC</code> or
       <code>-Includes</code> disables server-side includes completely
       regardless of the previous setting.</p>
     </div>

     <p>The default in the absence of any other settings is
     <code>All</code>.</p>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="Require" id="Require">Require</a> <a name="require" id="require">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Selects which authenticated users can access
 a resource</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Require <var>entity-name</var> [<var>entity-name</var>] ...</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>This directive selects which authenticated users can access
     a resource. The allowed syntaxes are:</p>

     <dl>
       <dt><code>Require user <var>userid</var> [<var>userid</var>]
       ...</code></dt>
       <dd>Only the named users can access the resource.</dd>

       <dt><code>Require group <var>group-name</var> [<var>group-name</var>]
       ...</code></dt>
       <dd>Only users in the named groups can access the resource.</dd>

       <dt><code>Require valid-user</code></dt>
       <dd>All valid users can access the resource.</dd>
     </dl>

     <p><code class="directive">Require</code> must be accompanied by
     <code class="directive"><a href="#authname">AuthName</a></code> and <code class="directive"><a href="#authtype">AuthType</a></code> directives, and directives such
     as <code class="directive"><a href="../mod/mod_auth.html#authuserfile">AuthUserFile</a></code>
     and <code class="directive"><a href="../mod/mod_auth.html#authgroupfile">AuthGroupFile</a></code> (to
     define users and groups) in order to work correctly. Example:</p>

     <div class="example"><p><code>
        AuthType Basic<br />
        AuthName "Restricted Resource"<br />
        AuthUserFile /web/users<br />
        AuthGroupFile /web/groups<br />
        Require group admin
     </code></p></div>

     <p>Access controls which are applied in this way are effective for
     <strong>all</strong> methods. <strong>This is what is normally
     desired.</strong> If you wish to apply access controls only to
     specific methods, while leaving other methods unprotected, then
     place the <code class="directive">Require</code> statement into a
     <code class="directive"><a href="#limit">&lt;Limit&gt;</a></code>
     section.</p>

 <h3>See also</h3>
 <ul>
 <li><code class="directive"><a href="#satisfy">Satisfy</a></code></li>
 <li><code class="module"><a href="../mod/mod_access.html">mod_access</a></code></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="RLimitCPU" id="RLimitCPU">RLimitCPU</a> <a name="rlimitcpu" id="rlimitcpu">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the CPU consumption of processes launched
 by Apache children</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>RLimitCPU <var>seconds</var>|max [<var>seconds</var>|max]</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>Takes 1 or 2 parameters. The first parameter sets the soft
     resource limit for all processes and the second parameter sets
     the maximum resource limit. Either parameter can be a number,
     or <code>max</code> to indicate to the server that the limit should
     be set to the maximum allowed by the operating system
     configuration. Raising the maximum resource limit requires that
     the server is running as <code>root</code>, or in the initial startup
     phase.</p>

     <p>This applies to processes forked off from Apache children
     servicing requests, not the Apache children themselves. This
     includes CGI scripts and SSI exec commands, but not any
     processes forked off from the Apache parent such as piped
     logs.</p>

     <p>CPU resource limits are expressed in seconds per
     process.</p>

 <h3>See also</h3>
 <ul>
 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="RLimitMEM" id="RLimitMEM">RLimitMEM</a> <a name="rlimitmem" id="rlimitmem">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the memory consumption of processes launched
 by Apache children</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>RLimitMEM <var>bytes</var>|max [<var>bytes</var>|max]</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>Takes 1 or 2 parameters. The first parameter sets the soft
     resource limit for all processes and the second parameter sets
     the maximum resource limit. Either parameter can be a number,
     or <code>max</code> to indicate to the server that the limit should
     be set to the maximum allowed by the operating system
     configuration. Raising the maximum resource limit requires that
     the server is running as <code>root</code>, or in the initial startup
     phase.</p>

     <p>This applies to processes forked off from Apache children
     servicing requests, not the Apache children themselves. This
     includes CGI scripts and SSI exec commands, but not any
     processes forked off from the Apache parent such as piped
     logs.</p>

     <p>Memory resource limits are expressed in bytes per
     process.</p>

 <h3>See also</h3>
 <ul>
 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
 <li><code class="directive"><a href="#rlimitnproc">RLimitNPROC</a></code></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="RLimitNPROC" id="RLimitNPROC">RLimitNPROC</a> <a name="rlimitnproc" id="rlimitnproc">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limits the number of processes that can be launched by
 processes launched by Apache children</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>RLimitNPROC <var>number</var>|max [<var>number</var>|max]</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Unset; uses operating system defaults</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>Takes 1 or 2 parameters. The first parameter sets the soft
     resource limit for all processes and the second parameter sets
     the maximum resource limit. Either parameter can be a number,
     or <code>max</code> to indicate to the server that the limit
     should be set to the maximum allowed by the operating system
     configuration. Raising the maximum resource limit requires that
     the server is running as <code>root</code>, or in the initial startup
     phase.</p>

     <p>This applies to processes forked off from Apache children
     servicing requests, not the Apache children themselves. This
     includes CGI scripts and SSI exec commands, but not any
     processes forked off from the Apache parent such as piped
     logs.</p>

     <p>Process limits control the number of processes per user.</p>

     <div class="note"><h3>Note</h3>
       <p>If CGI processes are <strong>not</strong> running
       under user ids other than the web server user id, this directive
       will limit the number of processes that the server itself can
       create. Evidence of this situation will be indicated by
       <strong><code>cannot fork</code></strong> messages in the
       <code>error_log</code>.</p>
     </div>

 <h3>See also</h3>
 <ul>
 <li><code class="directive"><a href="#rlimitmem">RLimitMEM</a></code></li>
 <li><code class="directive"><a href="#rlimitcpu">RLimitCPU</a></code></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="Satisfy" id="Satisfy">Satisfy</a> <a name="satisfy" id="satisfy">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Interaction between host-level access control and
 user authentication</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Satisfy Any|All</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Satisfy All</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Influenced by <code class="directive"><a href="#limit">&lt;Limit&gt;</a></code> and <code class="directive"><a href="#limitexcept">&lt;LimitExcept&gt;</a></code> in version 2.0.51 and
 later</td></tr>
 </table>
     <p>Access policy if both <code class="directive"><a href="../mod/mod_access.html#allow">Allow</a></code> and <code class="directive"><a href="#require">Require</a></code> used. The parameter can be
     either <code>All</code> or <code>Any</code>. This directive is only
     useful if access to a particular area is being restricted by both
     username/password <em>and</em> client host address. In this case
     the default behavior (<code>All</code>) is to require that the client
     passes the address access restriction <em>and</em> enters a valid
     username and password. With the <code>Any</code> option the client will be
     granted access if they either pass the host restriction or enter a
     valid username and password. This can be used to password restrict
     an area, but to let clients from particular addresses in without
     prompting for a password.</p>

     <p>For example, if you wanted to let people on your network have
     unrestricted access to a portion of your website, but require that
     people outside of your network provide a password, you could use a
     configuration similar to the following:</p>

     <div class="example"><p><code>
       Require valid-user<br />
       Allow from 192.168.1<br />
       Satisfy Any
     </code></p></div>

     <p>Since version 2.0.51 <code class="directive">Satisfy</code> directives can
     be restricted to particular methods by <code class="directive"><a href="#limit">&lt;Limit&gt;</a></code> and <code class="directive"><a href="#limitexcept">&lt;LimitExcept&gt;</a></code> sections.</p>

 <h3>See also</h3>
 <ul>
 <li><code class="directive"><a href="../mod/mod_access.html#allow">Allow</a></code></li>
 <li><code class="directive"><a href="#require">Require</a></code></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="ScriptInterpreterSource" id="ScriptInterpreterSource">ScriptInterpreterSource</a> <a name="scriptinterpretersource" id="scriptinterpretersource">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Technique for locating the interpreter for CGI
 scripts</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ScriptInterpreterSource Registry|Registry-Strict|Script</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ScriptInterpreterSource Script</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Win32 only;
 option <code>Registry-Strict</code> is available in Apache 2.0 and
 later</td></tr>
 </table>
     <p>This directive is used to control how Apache finds the
     interpreter used to run CGI scripts. The default setting is
     <code>Script</code>. This causes Apache to use the interpreter pointed to
     by the shebang line (first line, starting with <code>#!</code>) in the
     script. On Win32 systems this line usually looks like:</p>

     <div class="example"><p><code>
       #!C:/Perl/bin/perl.exe
     </code></p></div>

     <p>or, if <code>perl</code> is in the <code>PATH</code>, simply:</p>

     <div class="example"><p><code>
       #!perl
     </code></p></div>

     <p>Setting <code>ScriptInterpreterSource Registry</code> will
     cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
     searched using the script file extension (e.g., <code>.pl</code>) as a
     search key. The command defined by the registry subkey
     <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
     <code>Shell\Open\Command</code> is used to open the script file. If the
     registry keys cannot be found, Apache falls back to the behavior of the
     <code>Script</code> option.</p>

     <div class="warning"><h3>Security</h3>
     <p>Be careful when using <code>ScriptInterpreterSource
     Registry</code> with <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>'ed directories, because
     Apache will try to execute <strong>every</strong> file within this
     directory. The <code>Registry</code> setting may cause undesired
     program calls on files which are typically not executed. For
     example, the default open command on <code>.htm</code> files on
     most Windows systems will execute Microsoft Internet Explorer, so
     any HTTP request for an <code>.htm</code> file existing within the
     script directory would start the browser in the background on the
     server. This is a good way to crash your system within a minute or
     so.</p>
     </div>

     <p>The option <code>Registry-Strict</code> which is new in Apache
     2.0 does the same thing as <code>Registry</code> but uses only the
     subkey <code>Shell\ExecCGI\Command</code>. The
     <code>ExecCGI</code> key is not a common one. It must be
     configured manually in the windows registry and hence prevents
     accidental program calls on your system.</p>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="ServerAdmin" id="ServerAdmin">ServerAdmin</a> <a name="serveradmin" id="serveradmin">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Email address that the server includes in error
 messages sent to the client</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAdmin <var>email-address</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>The <code class="directive">ServerAdmin</code> sets the e-mail address
     that the server includes in any error messages it returns to the
     client.</p>

     <p>It may be worth setting up a dedicated address for this, e.g.</p>

     <div class="example"><p><code>
       ServerAdmin www-admin@foo.example.com
     </code></p></div>
     <p>as users do not always mention that they are talking about the
     server!</p>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="ServerAlias" id="ServerAlias">ServerAlias</a> <a name="serveralias" id="serveralias">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Alternate names for a host used when matching requests
 to name-virtual hosts</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>The <code class="directive">ServerAlias</code> directive sets the
     alternate names for a host, for use with <a href="../vhosts/name-based.html">name-based virtual hosts</a>.</p>

     <div class="example"><p><code>
       &lt;VirtualHost *&gt;<br />
       ServerName server.domain.com<br />
       ServerAlias server server2.domain.com server2<br />
       # ...<br />
       &lt;/VirtualHost&gt;
     </code></p></div>

 <h3>See also</h3>
 <ul>
 <li><a href="../vhosts/">Apache Virtual Host documentation</a></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="ServerName" id="ServerName">ServerName</a> <a name="servername" id="servername">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hostname and port that the server uses to identify
 itself</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerName <var>fully-qualified-domain-name</var>[:<var>port</var>]</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>In version 2.0, this
      directive supersedes the functionality of the <code class="directive">Port</code>
      directive from version 1.3.</td></tr>
 </table>
     <p>The <code class="directive">ServerName</code> directive sets the hostname and
     port that the server uses to identify itself.  This is used when
     creating redirection URLs. For example, if the name of the
     machine hosting the web server is <code>simple.example.com</code>,
     but the machine also has the DNS alias <code>www.example.com</code>
     and you wish the web server to be so identified, the following
     directive should be used:</p>

     <div class="example"><p><code>
       ServerName www.example.com:80
     </code></p></div>

     <p>If no <code class="directive">ServerName</code> is specified, then the
     server attempts to deduce the hostname by performing a reverse
     lookup on the IP address. If no port is specified in the
     <code class="directive">ServerName</code>, then the server will use the port
     from the incoming
     request. For optimal reliability and predictability, you should
     specify an explicit hostname and port using the
     <code class="directive">ServerName</code> directive.</p>

     <p>If you are using <a href="../vhosts/name-based.html">name-based virtual hosts</a>,
     the <code class="directive">ServerName</code> inside a
     <code class="directive"><a href="#virtualhost">&lt;VirtualHost&gt;</a></code>
     section specifies what hostname must appear in the request's
     <code>Host:</code> header to match this virtual host.</p>

     <p>See the description of the
     <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> directive for
     settings which determine whether self-referential URL's (e.g., by the
     <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> module) will refer to the
     specified port, or to the port number given in the client's request.
     </p>

 <h3>See also</h3>
 <ul>
 <li><a href="../dns-caveats.html">Issues Regarding DNS and
     Apache</a></li>
 <li><a href="../vhosts/">Apache virtual host
     documentation</a></li>
 <li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
 <li><code class="directive"><a href="#namevirtualhost">NameVirtualHost</a></code></li>
 <li><code class="directive"><a href="#serveralias">ServerAlias</a></code></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="ServerPath" id="ServerPath">ServerPath</a> <a name="serverpath" id="serverpath">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Legacy URL pathname for a name-based virtual host that
 is accessed by an incompatible browser</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerPath <var>URL-path</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>The <code class="directive">ServerPath</code> directive sets the legacy
     URL pathname for a host, for use with <a href="../vhosts/">name-based virtual hosts</a>.</p>

 <h3>See also</h3>
 <ul>
 <li><a href="../vhosts/">Apache Virtual Host documentation</a></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="ServerRoot" id="ServerRoot">ServerRoot</a> <a name="serverroot" id="serverroot">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Base directory for the server installation</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerRoot <var>directory-path</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerRoot /usr/local/apache</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>The <code class="directive">ServerRoot</code> directive sets the
     directory in which the server lives. Typically it will contain the
     subdirectories <code>conf/</code> and <code>logs/</code>. Relative
     paths in other configuration directives (such as <code class="directive"><a href="#include">Include</a></code> or <code class="directive"><a href="../mod/mod_so.html#loadmodule">LoadModule</a></code>, for example) are taken as
     relative to this directory.</p>

     <div class="example"><h3>Example</h3><p><code>
       ServerRoot /home/httpd
     </code></p></div>


 <h3>See also</h3>
 <ul>
 <li><a href="../invoking.html">the <code>-d</code>
     option to <code>httpd</code></a></li>
 <li><a href="../misc/security_tips.html#serverroot">the
     security tips</a> for information on how to properly set
     permissions on the <code class="directive">ServerRoot</code></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="ServerSignature" id="ServerSignature">ServerSignature</a> <a name="serversignature" id="serversignature">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the footer on server-generated documents</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerSignature On|Off|EMail</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerSignature Off</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>The <code class="directive">ServerSignature</code> directive allows the
     configuration of a trailing footer line under server-generated
     documents (error messages, <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> ftp directory
     listings, <code class="module"><a href="../mod/mod_info.html">mod_info</a></code> output, ...). The reason why you
     would want to enable such a footer line is that in a chain of proxies,
     the user often has no possibility to tell which of the chained servers
     actually produced a returned error message.</p>

     <p>The <code>Off</code>
     setting, which is the default, suppresses the footer line (and is
     therefore compatible with the behavior of Apache-1.2 and
     below). The <code>On</code> setting simply adds a line with the
     server version number and <code class="directive"><a href="#servername">ServerName</a></code> of the serving virtual host,
     and the <code>EMail</code> setting additionally creates a
     "mailto:" reference to the <code class="directive"><a href="#serveradmin">ServerAdmin</a></code> of the referenced
     document.</p>

     <p>After version 2.0.44, the details of the server version number
     presented are controlled by the <code class="directive"><a href="#servertokens">ServerTokens</a></code> directive.</p>

 <h3>See also</h3>
 <ul>
 <li><code class="directive"><a href="#servertokens">ServerTokens</a></code></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="ServerTokens" id="ServerTokens">ServerTokens</a> <a name="servertokens" id="servertokens">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures the <code>Server</code> HTTP response
 header</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerTokens Major|Minor|Min[imal]|Prod[uctOnly]|OS|Full</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ServerTokens Full</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>This directive controls whether <code>Server</code> response
     header field which is sent back to clients includes a
     description of the generic OS-type of the server as well as
     information about compiled-in modules.</p>

     <dl>
       <dt><code>ServerTokens Prod[uctOnly]</code></dt>

       <dd>Server sends (<em>e.g.</em>): <code>Server:
       Apache</code></dd>

       <dt><code>ServerTokens Major</code></dt>

       <dd>Server sends (<em>e.g.</em>): <code>Server:
       Apache/2</code></dd>

       <dt><code>ServerTokens Minor</code></dt>

       <dd>Server sends (<em>e.g.</em>): <code>Server:
       Apache/2.0</code></dd>

       <dt><code>ServerTokens Min[imal]</code></dt>

       <dd>Server sends (<em>e.g.</em>): <code>Server:
       Apache/2.0.41</code></dd>

       <dt><code>ServerTokens OS</code></dt>

       <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.0.41
       (Unix)</code></dd>

       <dt><code>ServerTokens Full</code> (or not specified)</dt>

       <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.0.41
       (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
     </dl>

     <p>This setting applies to the entire server, and cannot be
     enabled or disabled on a virtualhost-by-virtualhost basis.</p>

     <p>After version 2.0.44, this directive also controls the
     information presented by the <code class="directive"><a href="#serversignature">ServerSignature</a></code> directive.</p>

 <h3>See also</h3>
 <ul>
 <li><code class="directive"><a href="#serversignature">ServerSignature</a></code></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="SetHandler" id="SetHandler">SetHandler</a> <a name="sethandler" id="sethandler">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forces all matching files to be processed by a
 handler</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetHandler <var>handler-name</var>|None</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Moved into the core in Apache 2.0</td></tr>
 </table>
     <p>When placed into an <code>.htaccess</code> file or a
     <code class="directive"><a href="#directory">&lt;Directory&gt;</a></code> or
     <code class="directive"><a href="#location">&lt;Location&gt;</a></code>
     section, this directive forces all matching files to be parsed
     through the <a href="../handler.html">handler</a> given by
     <var>handler-name</var>. For example, if you had a directory you
     wanted to be parsed entirely as imagemap rule files, regardless
     of extension, you might put the following into an
     <code>.htaccess</code> file in that directory:</p>

     <div class="example"><p><code>
       SetHandler imap-file
     </code></p></div>

     <p>Another example: if you wanted to have the server display a
     status report whenever a URL of
     <code>http://servername/status</code> was called, you might put
     the following into <code>httpd.conf</code>:</p>

     <div class="example"><p><code>
       &lt;Location /status&gt;<br />
       <span class="indent">
         SetHandler server-status<br />
       </span>
       &lt;/Location&gt;
     </code></p></div>

     <p>You can override an earlier defined <code class="directive">SetHandler</code>
     directive by using the value <code>None</code>.</p>

 <h3>See also</h3>
 <ul>
 <li><code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="SetInputFilter" id="SetInputFilter">SetInputFilter</a> <a name="setinputfilter" id="setinputfilter">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process client requests and POST
 input</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetInputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>The <code class="directive">SetInputFilter</code> directive sets the
     filter or filters which will process client requests and POST
     input when they are received by the server. This is in addition to
     any filters defined elsewhere, including the
     <code class="directive"><a href="../mod/mod_mime.html#addinputfilter">AddInputFilter</a></code>
     directive.</p>

     <p>If more than one filter is specified, they must be separated
     by semicolons in the order in which they should process the
     content.</p>

 <h3>See also</h3>
 <ul>
 <li><a href="../filter.html">Filters</a> documentation</li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="SetOutputFilter" id="SetOutputFilter">SetOutputFilter</a> <a name="setoutputfilter" id="setoutputfilter">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the filters that will process responses from the
 server</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>The <code class="directive">SetOutputFilter</code> directive sets the filters
     which will process responses from the server before they are
     sent to the client. This is in addition to any filters defined
     elsewhere, including the
     <code class="directive"><a href="../mod/mod_mime.html#addoutputfilter">AddOutputFilter</a></code>
     directive.</p>

     <p>For example, the following configuration will process all files
     in the <code>/www/data/</code> directory for server-side
     includes.</p>

     <div class="example"><p><code>
       &lt;Directory /www/data/&gt;<br />
       <span class="indent">
         SetOutputFilter INCLUDES<br />
       </span>
       &lt;/Directory&gt;
     </code></p></div>

     <p>If more than one filter is specified, they must be separated
     by semicolons in the order in which they should process the
     content.</p>

 <h3>See also</h3>
 <ul>
 <li><a href="../filter.html">Filters</a> documentation</li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="TimeOut" id="TimeOut">TimeOut</a> <a name="timeout" id="timeout">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Amount of time the server will wait for
 certain events before failing a request</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TimeOut <var>seconds</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TimeOut 300</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>The <code class="directive">TimeOut</code> directive currently defines
     the amount of time Apache will wait for three things:</p>

     <ol>
       <li>The total amount of time it takes to receive a GET
       request.</li>

       <li>The amount of time between receipt of TCP packets on a
       POST or PUT request.</li>

       <li>The amount of time between ACKs on transmissions of TCP
       packets in responses.</li>
     </ol>

     <p>We plan on making these separately configurable at some point
     down the road. The timer used to default to 1200 before 1.2,
     but has been lowered to 300 which is still far more than
     necessary in most situations. It is not set any lower by
     default because there may still be odd places in the code where
     the timer is not reset when a packet is sent. </p>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="TraceEnable" id="TraceEnable">TraceEnable</a> <a name="traceenable" id="traceenable">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines the behaviour on <code>TRACE</code>
 requests</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>TraceEnable <var>[on|off|extended]</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>TraceEnable on</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 1.3.34, 2.0.55 and later</td></tr>
 </table>
     <p>This directive overrides the behavior of <code>TRACE</code> for both
     the core server and <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>.  The default
     <code>TraceEnable on</code> permits <code>TRACE</code> requests per
     RFC 2616, which disallows any request body to accompany the request.
     <code>TraceEnable off</code> causes the core server and
     <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> to return a <code>405</code> (Method not
     allowed) error to the client.</p>

     <p>Finally, for testing and diagnostic purposes only, request
     bodies may be allowed using the non-compliant <code>TraceEnable
     extended</code> directive.  The core (as an origin server) will
     restrict the request body to 64k (plus 8k for chunk headers if
     <code>Transfer-Encoding: chunked</code> is used).  The core will
     reflect the full headers and all chunk headers with the response
     body.  As a proxy server, the request body is not restricted to 64k.</p>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="UseCanonicalName" id="UseCanonicalName">UseCanonicalName</a> <a name="usecanonicalname" id="usecanonicalname">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures how the server determines its own name and
 port</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>UseCanonicalName On|Off|DNS</code></td></tr>
 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalName On</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p>In many situations Apache must construct a <em>self-referential</em>
     URL -- that is, a URL that refers back to the same server. With
     <code>UseCanonicalName On</code> Apache will use the hostname and port
     specified in the <code class="directive"><a href="#servername">ServerName</a></code>
     directive to construct the canonical name for the server. This name
     is used in all self-referential URLs, and for the values of
     <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>

     <p>With <code>UseCanonicalName Off</code> Apache will form
     self-referential URLs using the hostname and port supplied by
     the client if any are supplied (otherwise it will use the
     canonical name, as defined above). These values are the same
     that are used to implement <a href="../vhosts/name-based.html">name based virtual hosts</a>,
     and are available with the same clients. The CGI variables
     <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
     constructed from the client supplied values as well.</p>

     <p>An example where this may be useful is on an intranet server
     where you have users connecting to the machine using short
     names such as <code>www</code>. You'll notice that if the users
     type a shortname, and a URL which is a directory, such as
     <code>http://www/splat</code>, <em>without the trailing
     slash</em> then Apache will redirect them to
     <code>http://www.domain.com/splat/</code>. If you have
     authentication enabled, this will cause the user to have to
     authenticate twice (once for <code>www</code> and once again
     for <code>www.domain.com</code> -- see <a href="http://httpd.apache.org/docs/misc/FAQ.html#prompted-twice">the
     FAQ on this subject for more information</a>). But if
     <code class="directive">UseCanonicalName</code> is set <code>Off</code>, then
     Apache will redirect to <code>http://www/splat/</code>.</p>

     <p>There is a third option, <code>UseCanonicalName DNS</code>,
     which is intended for use with mass IP-based virtual hosting to
     support ancient clients that do not provide a
     <code>Host:</code> header. With this option Apache does a
     reverse DNS lookup on the server IP address that the client
     connected to in order to work out self-referential URLs.</p>

     <div class="warning"><h3>Warning</h3>
     <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>
     they may be broken by this option. The client is essentially free
     to give whatever value they want as a hostname. But if the CGI is
     only using <code>SERVER_NAME</code> to construct self-referential URLs
     then it should be just fine.</p>
     </div>

 <h3>See also</h3>
 <ul>
 <li><code class="directive"><a href="#servername">ServerName</a></code></li>
 <li><code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code></li>
 </ul>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="VirtualHost" id="VirtualHost">&lt;VirtualHost&gt;</a> <a name="virtualhost" id="virtualhost">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Contains directives that apply only to a specific
 hostname or IP address</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>&lt;VirtualHost
     <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
     ...&gt; ... &lt;/VirtualHost&gt;</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Core</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>core</td></tr>
 </table>
     <p><code class="directive">&lt;VirtualHost&gt;</code> and
     <code>&lt;/VirtualHost&gt;</code> are used to enclose a group of
     directives that will apply only to a particular virtual host. Any
     directive that is allowed in a virtual host context may be
     used. When the server receives a request for a document on a
     particular virtual host, it uses the configuration directives
     enclosed in the <code class="directive">&lt;VirtualHost&gt;</code>
     section. <var>Addr</var> can be:</p>

     <ul>
       <li>The IP address of the virtual host;</li>

       <li>A fully qualified domain name for the IP address of the
       virtual host;</li>

       <li>The character <code>*</code>, which is used only in combination with
       <code>NameVirtualHost *</code> to match all IP addresses; or</li>

       <li>The string <code>_default_</code>, which is used only
       with IP virtual hosting to catch unmatched IP addresses.</li>
     </ul>

     <div class="example"><h3>Example</h3><p><code>
       &lt;VirtualHost 10.1.2.3&gt;<br />
       <span class="indent">
         ServerAdmin webmaster@host.foo.com<br />
         DocumentRoot /www/docs/host.foo.com<br />
         ServerName host.foo.com<br />
         ErrorLog logs/host.foo.com-error_log<br />
         TransferLog logs/host.foo.com-access_log<br />
       </span>
       &lt;/VirtualHost&gt;
     </code></p></div>


     <p>IPv6 addresses must be specified in square brackets because
     the optional port number could not be determined otherwise.  An
     IPv6 example is shown below:</p>

     <div class="example"><p><code>
       &lt;VirtualHost [2001:db8::a00:20ff:fea7:ccea]&gt;<br />
       <span class="indent">
         ServerAdmin webmaster@host.example.com<br />
         DocumentRoot /www/docs/host.example.com<br />
         ServerName host.example.com<br />
         ErrorLog logs/host.example.com-error_log<br />
         TransferLog logs/host.example.com-access_log<br />
       </span>
       &lt;/VirtualHost&gt;
     </code></p></div>

     <p>Each Virtual Host must correspond to a different IP address,
     different port number or a different host name for the server,
     in the former case the server machine must be configured to
     accept IP packets for multiple addresses. (If the machine does
     not have multiple network interfaces, then this can be
     accomplished with the <code>ifconfig alias</code> command -- if
     your OS supports it).</p>

     <div class="note"><h3>Note</h3>
     <p>The use of <code class="directive">&lt;VirtualHost&gt;</code> does
     <strong>not</strong> affect what addresses Apache listens on. You
     may need to ensure that Apache is listening on the correct addresses
     using <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>.</p>
     </div>

     <p>When using IP-based virtual hosting, the special name
     <code>_default_</code> can be specified in
     which case this virtual host will match any IP address that is
     not explicitly listed in another virtual host. In the absence
     of any <code>_default_</code> virtual host the "main" server config,
     consisting of all those definitions outside any VirtualHost
     section, is used when no IP-match occurs.  (But note that any IP
     address that matches a <code class="directive"><a href="#namevirtualhost">NameVirtualHost</a></code> directive will use neither
     the "main" server config nor the <code>_default_</code> virtual host.
     See the <a href="../vhosts/name-based.html">name-based virtual hosting</a>
     documentation for further details.)</p>

     <p>You can specify a <code>:port</code> to change the port that is
     matched. If unspecified then it defaults to the same port as the
     most recent <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>
     statement of the main server. You may also specify <code>:*</code>
     to match all ports on that address. (This is recommended when used
     with <code>_default_</code>.)</p>

     <div class="warning"><h3>Security</h3>
     <p>See the <a href="../misc/security_tips.html">security tips</a>
     document for details on why your security could be compromised if the
     directory where log files are stored is writable by anyone other
     than the user that starts the server.</p>
     </div>

 <h3>See also</h3>
 <ul>
 <li><a href="../vhosts/">Apache Virtual Host documentation</a></li>
 <li><a href="../dns-caveats.html">Issues Regarding DNS and
     Apache</a></li>
 <li><a href="../bind.html">Setting
     which addresses and ports Apache uses</a></li>
 <li><a href="../sections.html">How &lt;Directory&gt;, &lt;Location&gt;
     and &lt;Files&gt; sections work</a> for an explanation of how these
     different sections are combined when a request is received</li>
 </ul>
 </div>
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