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<p class="apache">Apache HTTP Server Version 2.2</p>
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<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> |
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<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="#acceptfilter">AcceptFilter</a></li>
<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="#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="#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="#usecanonicalphysicalport">UseCanonicalPhysicalPort</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="AcceptFilter" id="AcceptFilter">AcceptFilter</a> <a name="acceptfilter" id="acceptfilter">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configures optimizations for a Protocol's Listener Sockets</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptFilter <var>protocol</var> <var>accept_filter</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>
<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.1.5 and later</td></tr>
</table>
    <p>This directive enables operating system specific optimizations for a 
       listening socket by the Protocol type. The basic premise is for the 
       kernel to not send a socket to the server process until either data 
       is received or an entire HTTP Request is buffered. Only
       <a href="http://www.freebsd.org/cgi/man.cgi?query=accept_filter&amp;sektion=9">
       FreeBSD's Accept Filters</a> and Linux's more primitive 
       <code>TCP_DEFER_ACCEPT</code> are currently supported.</p>

    <p>The default values on FreeBSD are:</p>
    <div class="example"><p><code>
        AcceptFilter http httpready <br />
        AcceptFilter https dataready
    </code></p></div>
    
    <p>The <code>httpready</code> accept filter buffers entire HTTP requests at
       the kernel level.  Once an entire request is received, the kernel then 
       sends it to the server. See the 
       <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_http&amp;sektion=9">
       accf_http(9)</a> man page for more details.  Since HTTPS requests are 
       encrypted only the <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_data&amp;sektion=9">
       accf_data(9)</a> filter is used.</p>

    <p>The default values on Linux are:</p>
    <div class="example"><p><code>
        AcceptFilter http data <br />
        AcceptFilter https data
    </code></p></div>

    <p>Linux's <code>TCP_DEFER_ACCEPT</code> does not support buffering http
       requests.  Any value besides <code>none</code> will enable 
       <code>TCP_DEFER_ACCEPT</code> on that listener. For more details
       see the Linux 
       <a href="http://homepages.cwi.nl/~aeb/linux/man2html/man7/tcp.7.html">
       tcp(7)</a> man page.</p>

    <p>Using <code>none</code> for an argument will disable any accept filters 
       for that protocol.  This is useful for protocols that require a server
       send data first, such as <code>nntp</code>:</p>
    <div class="example"><p><code>AcceptFilter nntp none</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="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; deprecated in Apache 2.1 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 <a class="glossarylink" href="../glossary.html#mime-type" title="see glossary">MIME-type</a>.  Because of certain
    problems discussed below, this directive is deprecated.  The same
    functionality is available using <code class="module"><a href="../mod/mod_filter.html">mod_filter</a></code>.</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 <a class="glossarylink" href="../glossary.html#mime-type" title="see glossary">MIME-type</a> 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>

    </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_authn_dbm.html#authdbmgroupfile">AuthDBMGroupFile</a></code>,
      <code class="directive"><a href="../mod/mod_authn_dbm.html#authdbmuserfile">AuthDBMUserFile</a></code>,
      <code class="directive"><a href="../mod/mod_authz_groupfile.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_authn_file.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>), document meta data (<code class="directive"><a href="../mod/mod_headers.html#header">Header</a></code>, <code class="directive"><a href="../mod/mod_headers.html#requestheader">RequestHeader</a></code>, <code class="directive"><a href="../mod/mod_setenvif.html#setenvif">SetEnvIf</a></code>, <code class="directive"><a href="../mod/mod_setenvif.html#setenvifnocase">SetEnvIfNoCase</a></code>, <code class="directive"><a href="../mod/mod_setenvif.html#browsermatch">BrowserMatch</a></code>, <code class="directive"><a href="../mod/mod_usertrack.html#cookieexpires">CookieExpires</a></code>, <code class="directive"><a href="../mod/mod_usertrack.html#cookiedomain">CookieDomain</a></code>, <code class="directive"><a href="../mod/mod_usertrack.html#cookiestyle">CookieStyle</a></code>, <code class="directive"><a href="../mod/mod_usertrack.html#cookietracking">CookieTracking</a></code>, <code class="directive"><a href="../mod/mod_usertrack.html#cookiename">CookieName</a></code>),
      <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> directives <code class="directive"><a href="../mod/mod_rewrite.html#rewriteengine">RewriteEngine</a></code>, <code class="directive"><a href="../mod/mod_rewrite.html#rewriteoptions">RewriteOptions</a></code>, <code class="directive"><a href="../mod/mod_rewrite.html#rewritebase">RewriteBase</a></code>, <code class="directive"><a href="../mod/mod_rewrite.html#rewritecond">RewriteCond</a></code>, <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code>) and
      <code class="directive"><a href="../mod/mod_actions.html#action">Action</a></code> from
      <code class="module"><a href="../mod/mod_actions.html">mod_actions</a></code>.
      </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_authz_host.html#allow">Allow</a></code>, <code class="directive"><a href="../mod/mod_authz_host.html#deny">Deny</a></code> and <code class="directive"><a href="../mod/mod_authz_host.html#order">Order</a></code>).</dd>

      <dt>Options[=<var>Option</var>,...]</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>).
      An equal sign may be given followed by a comma (but no spaces)
      separated lists of options that may be set using the <code class="directive"><a href="#options">Options</a></code> command.</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_authn_file.html#authuserfile">AuthUserFile</a></code> and
    <code class="directive"><a href="../mod/mod_authz_groupfile.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. The authentication types available are
    <code>Basic</code> (implemented by
    <code class="module"><a href="../mod/mod_auth_basic.html">mod_auth_basic</a></code>) and <code>Digest</code>
    (implemented by <code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code>).</p>

    <p>To implement authentication, you must also use the <code class="directive"><a href="#authname">AuthName</a></code> and <code class="directive"><a href="#require">Require</a></code> directives.  In addition, the
    server must have an authentication-provider module such as
    <code class="module"><a href="../mod/mod_authn_file.html">mod_authn_file</a></code> and an authorization module such
    as <code class="module"><a href="../mod/mod_authz_user.html">mod_authz_user</a></code>.</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|none</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 <a class="glossarylink" href="../glossary.html#mime-type" title="see glossary">MIME types</a> mappings.</p>

    <p>The server SHOULD inform the client of the content-type of the
    document.  If the server is unable to determine this by normal
    means, it will set it to the configured
    <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>In cases where it can neither be determined by the server nor
    the administrator (e.g. a proxy), it is preferable to omit the MIME
    type altogether rather than provide information that may be false.
    This can be accomplished using</p>
    <div class="example"><p><code>
      DefaultType None
    </code></p></div>
    <p>DefaultType None is only available in httpd-2.2.7 and later.</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><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular
    expressions</a> 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 <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular 
    expression</a>. 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>. If the <var>directory-path</var> is 
    not absolute then it is assumed to be relative to the <code class="directive"><a href="#serverroot">ServerRoot</a></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>On Linux on Itanium, sendfile may be unable to handle files
    over 2GB in size.</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>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 class="warning"><h3>Warning</h3>
    Do not change the default for directories or locations that have WebDAV
    enabled and use <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> as a storage provider.
    <code class="module"><a href="../mod/mod_dav_fs.html">mod_dav_fs</a></code> uses <code>INode&nbsp;MTime&nbsp;Size</code>
    as a fixed format for <code>ETag</code> comparisons on conditional requests.
    These conditional requests will break if the <code>ETag</code> format is
    changed via <code class="directive">FileETag</code>.
    </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="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.
    <a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a> 
    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 <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular 
    expression</a>. 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_authz_host.html">mod_authz_host</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="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-file</var>|<var>module-identifier</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>
<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Module identifiers are available in version 2.1 and
later.</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</var></li>

      <li>!<var>module</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</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</var> is
    <strong>not</strong> included.</p>

    <p>The <var>module</var> argument can be either the module identifier or
    the file name of the module, at the time it was compiled.  For example,
    <code>rewrite_module</code> is the identifier and
    <code>mod_rewrite.c</code> is the file name. 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>

    <p>Running <code>apachectl configtest</code> will give you a list
    of the files that are being processed during the configuration
    check:</p>

    <div class="example"><p><code>
      root@host# apachectl configtest<br />
      Processing config file: /usr/local/apache2/conf/ssl.conf<br />
      Processing config file: /usr/local/apache2/conf/vhosts/vhost1.conf<br />
      Processing config file: /usr/local/apache2/conf/vhosts/vhost2.conf<br />
      Syntax OK
    </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 5</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>

</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</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>
<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</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>
<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</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> that will be 
    allowed on the HTTP request-line.</p>

    <p>The <code class="directive">LimitRequestLine</code> directive allows
    the server administrator to reduce or increase the limit on the allowed size
    of a client's HTTP request-line. 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>
<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. Neither wildcard character matches a / in the URL-path.</p>

    <p><a class="glossarylink" href="../glossary.html#regex" title="see glossary">Regular expressions</a>
    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 <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
    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="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>
      <p>Omitting this option should not be considered a security restriction,
      since symlink testing is subject to race conditions that make it
      circumventable.</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> <p>This option gets ignored if
      set inside a <code class="directive"><a href="#location">&lt;Location&gt;</a></code> section.</p>
      <p>This option should not be considered a security restriction,
      since symlink testing is subject to race conditions that make it
      circumventable.</p></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 restrictions are processed by authorization
    modules.  Some of the allowed syntaxes provided by
    <code class="module"><a href="../mod/mod_authz_user.html">mod_authz_user</a></code> and
    <code class="module"><a href="../mod/mod_authz_groupfile.html">mod_authz_groupfile</a></code> 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>Other authorization modules that implement require options
    include <code class="module"><a href="../mod/mod_authnz_ldap.html">mod_authnz_ldap</a></code>,
    <code class="module"><a href="../mod/mod_authz_dbm.html">mod_authz_dbm</a></code>, and
    <code class="module"><a href="../mod/mod_authz_owner.html">mod_authz_owner</a></code>.</p>

    <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_authn_file.html#authuserfile">AuthUserFile</a></code>
    and <code class="directive"><a href="../mod/mod_authz_groupfile.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>
 
    <p>If <code class="directive">Require</code> is used together with 
    the <code class="directive"><a href="../mod/mod_authz_host.html#allow">Allow</a></code> or
    <code class="directive"><a href="../mod/mod_authz_host.html#deny">Deny</a></code> directives,
    then the interaction of these restrictions is controlled by
    the <code class="directive"><a href="#satisfy">Satisfy</a></code> directive.</p>

    <div class="note"><h3>Removing controls in subdirectories</h3>
    <p>The following example shows how to use the <code class="directive"><a href="#satisfy">Satisfy</a></code> directive to disable access
    controls in a subdirectory of a protected directory.  This
    technique should be used with caution, because it will also
    disable any access controls imposed by
    <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code>.</p>
    <div class="example"><p><code>
      &lt;Directory /path/to/protected/&gt;<br />
        <span class="indent">
        Require user david<br />
        </span>
      &lt;/Directory&gt;<br />
      &lt;Directory /path/to/protected/unprotected&gt;<br />
        <span class="indent">
        # All access controls and authentication are disabled<br />
        # in this directory<br />
        Satisfy Any<br />
        Allow from all<br />
        </span>
      &lt;/Directory&gt;<br />
    </code></p></div>
    </div>
      

<h3>See also</h3>
<ul>
<li><a href="../howto/auth.html">Authentication, Authorization,
    and Access Control</a></li>
<li><code class="directive"><a href="#satisfy">Satisfy</a></code></li>
<li><code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</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_authz_host.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 />
      Order allow,deny<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_authz_host.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>

    <p>For example, the registry setting to have a script with the .pl extension
    processed via perl would be:</p>

    <div class="example"><p><code><code>HKEY_CLASSES_ROOT\.pl\Shell\ExecCGI\Command\(Default) =&gt; C:\Perl\bin\perl.exe -wT</code></code></p></div>


    <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>|<var>URL</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 contact address
    that the server includes in any error messages it returns to the
    client. If the <code>httpd</code> doesn't recognize the supplied argument
    as an URL, it
    assumes, that it's an <var>email-address</var> and prepends it with
    <code>mailto:</code> in hyperlink targets. However, it's recommended to
    actually use an email address, since there are a lot of CGI scripts that
    make that assumption. If you want to use an URL, it should point to another
    server under your control. Otherwise users may not be able to contact you in
    case of errors.</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>. The
    <code class="directive">ServerAlias</code> may include wildcards, if appropriate.</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>scheme</var>://]<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
    request scheme, 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>Sometimes, the server runs behind a device that processes SSL,
    such as a reverse proxy, load balancer or SSL offload
    appliance. When this is the case, specify the
    <code>https://</code> scheme and the port number to which the
    clients connect in the <code class="directive">ServerName</code> directive
    to make sure that the server generates the correct
    self-referential URLs. 
    </p>

    <p>See the description of the
    <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> and
    <code class="directive"><a href="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code>directives for
    settings which determine whether self-referential URLs (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="#usecanonicalphysicalport">UseCanonicalPhysicalPort</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 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>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="#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code></li>
<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="UseCanonicalPhysicalPort" id="UseCanonicalPhysicalPort">UseCanonicalPhysicalPort</a> <a name="usecanonicalphysicalport" id="usecanonicalphysicalport">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>UseCanonicalPhysicalPort On|Off</code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>UseCanonicalPhysicalPort 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>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>UseCanonicalPhysicalPort On</code> Apache will, when
    constructing the canonical port for the server to honor
    the <code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code> directive,
    provide the actual physical port number being used by this request
    as a potential port. With <code>UseCanonicalPhysicalPort Off</code>
    Apache will not ever use the actual physical port number, instead
    relying on all configured information to construct a valid port number.</p>

    <div class="note"><h3>Note</h3>
    <p>The ordering of when the physical port is used is as follows:<br /><br />
     <code>UseCanonicalName On</code></p>
     <ul>
      <li>Port provided in <code>Servername</code></li>
      <li>Physical port</li>
      <li>Default port</li>
     </ul>
     <code>UseCanonicalName Off | DNS</code>
     <ul>
      <li>Parsed port from <code>Host:</code> header</li>
      <li>Physical port</li>
      <li>Port provided in <code>Servername</code></li>
      <li>Default port</li>
     </ul>
    
    <p>With <code>UseCanonicalPhysicalPort Off</code>, the
    physical ports are removed from the ordering.</p>
    </div>


<h3>See also</h3>
<ul>
<li><code class="directive"><a href="#usecanonicalname">UseCanonicalName</a></code></li>
<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 (not recommended);</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>

    <p>A <code class="directive"><a href="#servername">ServerName</a></code> should be
    specified inside each <code class="directive">&lt;VirtualHost&gt;</code> block. If it is absent, the
    <code class="directive"><a href="#servername">ServerName</a></code> from the "main"
    server configuration will be inherited.</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>
</div>
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