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    <title>Apache Core Features</title>
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      <h3>Apache HTTP Server Version 1.3</h3>
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    <h1 align="CENTER">Apache Core Features</h1>

    <p>These configuration parameters control the core Apache
    features, and are always available.</p>

    <h2>Directives</h2>

    <ul>
      <li><a href="#acceptfilter">AcceptFilter</a></li>

      <li><a href="#acceptmutex">AcceptMutex</a></li>

      <li><a href="#accessconfig">AccessConfig</a></li>

      <li><a href="#accessfilename">AccessFileName</a></li>

      <li><a href="#adddefaultcharset">AddDefaultCharset</a></li>

      <li><a href="#addmodule">AddModule</a></li>

      <li><a href="#allowoverride">AllowOverride</a></li>

      <li><a href="#authname">AuthName</a></li>

      <li><a href="#authtype">AuthType</a></li>

      <li><a href="#bindaddress">BindAddress</a></li>

      <li><a href="#bs2000account">BS2000Account</a></li>

      <li><a href="#clearmodulelist">ClearModuleList</a></li>

      <li><a href="#contentdigest">ContentDigest</a></li>

      <li><a href="#coredumpdirectory">CoreDumpDirectory</a></li>

      <li><a href="#defaulttype">DefaultType</a></li>

      <li><a href="#directory">&lt;Directory&gt;</a></li>

      <li><a href="#directorymatch">&lt;DirectoryMatch&gt;</a></li>

      <li><a href="#documentroot">DocumentRoot</a></li>

      <li><a href="#ebcdicconvert">EBCDICConvert</a></li>

      <li><a
      href="#ebcdicconvertbytype">EBCDICConvertByType</a></li>

      <li><a href="#ebcdickludge">EBCDICKludge</a></li>

      <li><a href="#errordocument">ErrorDocument</a></li>

      <li><a href="#errorlog">ErrorLog</a></li>

      <li><a href="#fileetag">FileETag</a></li>

      <li><a href="#files">&lt;Files&gt;</a></li>

      <li><a href="#filesmatch">&lt;FilesMatch&gt;</a></li>

      <li><a href="#group">Group</a></li>

      <li><a href="#hostnamelookups">HostnameLookups</a></li>

      <li><a href="#identitycheck">IdentityCheck</a></li>

      <li><a href="#ifdefine">&lt;IfDefine&gt;</a></li>

      <li><a href="#ifmodule">&lt;IfModule&gt;</a></li>

      <li><a href="#include">Include</a></li>

      <li><a href="#keepalive">KeepAlive</a></li>

      <li><a href="#keepalivetimeout">KeepAliveTimeout</a></li>

      <li><a href="#limit">&lt;Limit&gt;</a></li>

      <li><a href="#limitexcept">&lt;LimitExcept&gt;</a></li>

      <li><a href="#limitrequestbody">LimitRequestBody</a></li>

      <li><a href="#limitrequestfields">LimitRequestFields</a></li>

      <li><a
      href="#limitrequestfieldsize">LimitRequestFieldsize</a></li>

      <li><a href="#limitrequestline">LimitRequestLine</a></li>

      <li><a href="#listen">Listen</a></li>

      <li><a href="#listenbacklog">ListenBacklog</a></li>

      <li><a href="#location">&lt;Location&gt;</a></li>

      <li><a href="#locationmatch">&lt;LocationMatch&gt;</a></li>

      <li><a href="#lockfile">LockFile</a></li>

      <li><a href="#loglevel">LogLevel</a></li>

      <li><a href="#maxclients">MaxClients</a></li>

      <li><a
      href="#maxkeepaliverequests">MaxKeepAliveRequests</a></li>

      <li><a
      href="#maxrequestsperchild">MaxRequestsPerChild</a></li>

      <li><a href="#maxspareservers">MaxSpareServers</a></li>

      <li><a href="#minspareservers">MinSpareServers</a></li>

      <li><a href="#namevirtualhost">NameVirtualHost</a></li>

      <li><a href="#options">Options</a></li>

      <li><a href="#pidfile">PidFile</a></li>

      <li><a href="#port">Port</a></li>

      <li><a href="#require">Require</a></li>

      <li><a href="#resourceconfig">ResourceConfig</a></li>

      <li><a href="#rlimitcpu">RLimitCPU</a></li>

      <li><a href="#rlimitmem">RLimitMEM</a></li>

      <li><a href="#rlimitnproc">RLimitNPROC</a></li>

      <li><a href="#satisfy">Satisfy</a></li>

      <li><a href="#scoreboardfile">ScoreBoardFile</a></li>

      <li><a
      href="#scriptinterpretersource">ScriptInterpreterSource</a></li>

      <li><a href="#sendbuffersize">SendBufferSize</a></li>

      <li><a href="#serveradmin">ServerAdmin</a></li>

      <li><a href="#serveralias">ServerAlias</a></li>

      <li><a href="#servername">ServerName</a></li>

      <li><a href="#serverpath">ServerPath</a></li>

      <li><a href="#serverroot">ServerRoot</a></li>

      <li><a href="#serversignature">ServerSignature</a></li>

      <li><a href="#servertokens">ServerTokens</a></li>

      <li><a href="#servertype">ServerType</a></li>

      <li><a href="#startservers">StartServers</a></li>

      <li><a href="#threadsperchild">ThreadsPerChild</a></li>

      <li><a href="#threadstacksize">ThreadStackSize</a></li>

      <li><a href="#timeout">TimeOut</a></li>

      <li><a href="#usecanonicalname">UseCanonicalName</a></li>

      <li><a href="#user">User</a></li>

      <li><a href="#virtualhost">&lt;VirtualHost&gt;</a></li>
    </ul>
    <hr />

    <h2><a id="acceptfilter" name="acceptfilter">AcceptFilter
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AcceptFilter
    on|off<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>AcceptFilter
    on</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server configt<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br /> 
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> AcceptFilter is
    available in Apache 1.3.22 and later
 
    <p><code>AcceptFilter</code> controls a BSD specific filter
    optimization. It is compiled in by default - and switched on by
    default if your system supports it (setsocketopt() option
    SO_ACCEPTFILTER). Currently only FreeBSD supports this.</p>

    <p>See the filter section on <a
    href="../misc/perf-bsd44.html">performance hints</a> for more
    information.</p>

    <p>The compile time flag <code>AP_ACCEPTFILTER_OFF</code> can
    be used to change the default to 'off'. <code>httpd -V</code>
    and <code>httpd -L</code> will show compile time defaults and
    whether or not SO_ACCEPTFILTER was defined during the
    compile.</p>

    <hr />

    <h2><a id="acceptmutex" name="acceptmutex">AcceptMutex
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AcceptMutex
    uslock|pthread|sysvsem|fcntl|flock|os2sem|tpfcore|none|default<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>AcceptMutex
    default</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core <br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> AcceptMutex is 
    available in Apache 1.3.21 and later.

    <p><code>AcceptMutex</code> controls which accept() mutex
    method Apache will use. Not all methods are available on all
    platforms, since the suite of methods is determined at
    compile-time. For a list of which methods are available for
    your particular build, the <code>httpd -L</code> command line
    option will list them out.</p>

    <p>The compile time flags <code>-D
    HAVE_METHOD_SERIALIZED_ACCEPT</code> can be used to add
    different methods to your build, or one can edit the
    <code>include/ap_config.h</code> file for your particular
    platform.</p>

    <p>This directive has no effect on Microsoft Windows.</p>

    <p>See the <a href="../misc/perf-tuning.html">performance tuning
    guide</a> for more information.</p>

    <hr />

    <h2><a id="accessconfig" name="accessconfig">AccessConfig
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AccessConfig
    <em>file-path</em>|<em>directory-path</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>AccessConfig
    conf/access.conf</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core <br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> The ability to
    specify a directory, rather than a file name, is only available in
    Apache 1.3.13 and later.  This directive will be eliminated in version
    2.0.

    <p>The server will read this file for more directives after
    reading the <a href="#resourceconfig">ResourceConfig</a> file.
    <em>File-path</em> is relative to the <a
    href="#serverroot">ServerRoot</a>. This feature can be disabled
    using:</p>

    <blockquote>
      <code>AccessConfig /dev/null</code>
    </blockquote>
    Or, on Win32 servers, 

    <blockquote>
      <code>AccessConfig nul</code>
    </blockquote>
    Historically, this file only contained <a
    href="#directory">&lt;Directory&gt;</a> sections; in fact it
    can now contain any server directive allowed in the <em>server
    config</em> context. However, since Apache version 1.3.4,
    the default <code>access.conf</code> file which ships with 
    Apache contains only comments, and all directives are placed
    in the main server configuration file, <code>httpd.conf</code>.

    <p>If <code>AccessConfig</code> points to a directory, rather than a
    file, Apache will read all files in that directory, and any
    subdirectory, and parse those as configuration files. Note that
    <emph>any</emph> file in the specified directory will be loaded as a
    configuration file, so make sure that you don't have stray files in
    this directory by mistake, such as temporary files created by your
    editor, for example.</p>

    <p><strong>See also:</strong> <a href="#include">Include</a> and <a
    href="#resourceconfig">ResourceConfig</a>.</p>
    <hr />

    <h2><a id="accessfilename" name="accessfilename">AccessFileName
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AccessFileName
    <em>filename</em> [<em>filename</em>] ...<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>AccessFileName
    .htaccess</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> AccessFileName
    can accept more than one filename only in Apache 1.3 and later 

    <p>When returning a document to the client the server looks for
    the first existing access control file from this list of names
    in every directory of the path to the document, if access
    control files are enabled for that directory. For example:</p>

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

    <blockquote>
      <code>&lt;Directory /&gt;<br />
       AllowOverride None<br />
       &lt;/Directory&gt;</code>
    </blockquote>

    <p><strong>See Also:</strong> <a
    href="#allowoverride">AllowOverride</a> and <a
    href="../configuring.html">Configuration Files</a></p>
    <hr />

    <h2><a id="adddefaultcharset"
    name="adddefaultcharset">AddDefaultCharset directive</a></h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AddDefaultCharset
    On|Off|<em>charset</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> all<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a>
    <code>AddDefaultCharset Off</code><br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a>
    AddDefaultCharset is only available in Apache 1.3.12 and later 

    <p>This directive specifies the name of the character set that
    will be added to any response that does not have any parameter
    on the content type in the HTTP headers. This will override any
    character set specified in the body of the document via a
    <code>META</code> tag. A setting of <code>AddDefaultCharset
    Off</code> disables this functionality. <code>AddDefaultCharset
    On</code> enables Apache's internal default charset of
    <code>iso-8859-1</code> as required by the directive. You can
    also specify an alternate <em>charset</em> to be used.</p>
    
    <p>For example:</p>

    <blockquote>
    <code>AddDefaultCharset utf-8</code>
    </blockquote>

    <hr />

    <h2><a id="addmodule" name="addmodule">AddModule
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AddModule
    <em>module</em> [<em>module</em>] ...<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config <br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> AddModule is
    only available in Apache 1.2 and later 

    <p>The server can have modules compiled in which are not
    actively in use. This directive can be used to enable the use
    of those modules. The server comes with a pre-loaded list of
    active modules; this list can be cleared with the <a
    href="#clearmodulelist">ClearModuleList</a> directive.</p>

    <p>For example:</p>

    <blockquote>
    <code>AddModule mod_include.c</code>
    </blockquote>

    <p><strong>See also</strong>: <a
    href="#clearmodulelist">ClearModuleList</a>, 
    <hr />

    <h2><a id="allowoverride" name="allowoverride">AllowOverride
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AllowOverride
    All|None|<em>directive-type</em> [<em>directive-type</em>]
    ...<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>AllowOverride
    All</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> directory<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>When the server finds an .htaccess file (as specified by <a
    href="#accessfilename">AccessFileName</a>) it needs to know
    which directives declared in that file can override earlier
    access information.</p>

    <p>When this directive is set to <code>None</code>, then
    .htaccess files are completely ignored. In this case, the
    server will not even attempt to read .htaccess 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
    .htaccess files.</p>

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

    <dl>
      <dt>AuthConfig</dt>

      <dd>

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

      <dt>FileInfo</dt>

      <dd>
      Allow use of the directives controlling document types (<a
      href="mod_mime.html#addencoding">AddEncoding</a>, <a
      href="mod_mime.html#addlanguage">AddLanguage</a>, <a
      href="mod_mime.html#addtype">AddType</a>, <a
      href="#defaulttype">DefaultType</a>, <a
      href="#errordocument">ErrorDocument</a>, <a
      href="mod_negotiation.html#languagepriority">LanguagePriority</a>,
      <em>etc.</em>).</dd>

      <dt>Indexes</dt>

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

      <dt>Limit</dt>

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

      <dt>Options</dt>

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

    <p>Example:</p>
    <blockquote><code>AllowOverride AuthConfig Indexes</code></blockquote>

    <p><strong>See Also:</strong> <a
    href="#accessfilename">AccessFileName</a> and <a
    href="../configuring.html">Configuration Files</a></p>
    <hr />

    <h2><a id="authname" name="authname">AuthName
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AuthName
    <em>auth-domain</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> directory,
    .htaccess<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> AuthConfig<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <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.
    <samp>AuthName</samp> takes a single argument; if the realm
    name contains spaces, it must be enclosed in quotation marks.
    It must be accompanied by <a href="#authtype">AuthType</a> and
    <a href="#require">Require</a> directives, and directives such
    as <a href="mod_auth.html#authuserfile">AuthUserFile</a> and <a
    href="mod_auth.html#authgroupfile">AuthGroupFile</a> to
    work.</p>

    <p>For example:</p>

    <blockquote><code>AuthName "Top Secret"</code></blockquote>

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

    <p><strong>See also:</strong> <a
    href="../howto/auth.html">Authentication, Authorization, and
    Access Control</a></p>
    <hr />

    <h2><a id="authtype" name="authtype">AuthType
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AuthType
    Basic|Digest<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> directory,
    .htaccess<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> AuthConfig<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>This directive selects the type of user authentication for a
    directory. Only <code>Basic</code> and <code>Digest</code> are
    currently implemented. 

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

    <p><strong>See also:</strong> <a
    href="../howto/auth.html">Authentication, Authorization, and
    Access Control</a></p>
    <hr />

    <h2><a id="bindaddress" name="bindaddress">BindAddress
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> BindAddress
    *|<em>IP-address</em>|<em>domain-name</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>BindAddress
    *</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> BindAddress is
    deprecated and will be eliminated in Apache 2.0.

    <p>A Unix&reg; http server can either listen for connections to
    every IP address of the server machine, or just one IP address
    of the server machine. If the argument to this directive is *,
    then the server will listen for connections on every IP
    address. Otherwise, the server can listen to only a specific
    <em>IP-address</em> or a fully-qualified Internet
    <em>domain-name</em>.</p>

    <p>For example:</p>

    <code>BindAddress 192.168.15.48</code><br />

    <p>Only one <code>BindAddress</code> directive can be used.</p>
    
    <p>This directive is deprecated and will be eliminated in
    Apache 2.0.  Equivalent functionality and more control over the
    address and ports Apache listens to is available using the
    <code><a href="#listen">Listen</a></code>
    directive.</p>

    <p><code>BindAddress</code> can be used as an alternative
    method for supporting <a href="../vhosts/">virtual hosts</a>
    using multiple independent servers, instead of using <code><a
    href="#virtualhost">&lt;VirtualHost&gt;</a></code>
    sections.</p>

    <p><strong>See Also:</strong> <a href="../dns-caveats.html">DNS
    Issues</a><br />
     <strong>See Also:</strong> <a href="../bind.html">Setting
    which addresses and ports Apache uses</a></p>
    <hr />

    <h2><a id="bs2000account" name="bs2000account">BS2000Account
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> BS2000Account
    <em>account</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <em>none</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> BS2000Account is
    only available for BS2000 machines, as of Apache 1.3 and later.
    

    <p>The <code>BS2000Account</code> directive is available for
    BS2000 hosts only. It must be used to define the account number
    for the non-privileged apache server user (which was configured
    using the <a href="#user">User</a> directive). This is required
    by the BS2000 POSIX subsystem (to change the underlying BS2000
    task environment by performing a sub-LOGON) to prevent CGI
    scripts from accessing resources of the privileged account
    which started the server, usually <samp>SYSROOT</samp>.<br />
     Only one <code>BS2000Account</code> directive can be used.</p>

    <p><strong>See Also:</strong> <a href="../ebcdic.html">Apache
    EBCDIC port</a></p>
    <hr />

    <h2><a id="clearmodulelist"
    name="clearmodulelist">ClearModuleList directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ClearModuleList<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> ClearModuleList
    is only available in Apache 1.2 and later 

    <p>The server comes with a built-in list of active modules.
    This directive clears the list. It is assumed that the list
    will then be re-populated using the <a
    href="#addmodule">AddModule</a> directive.</p>
    <hr />

    <h2><a id="contentdigest" name="contentdigest">ContentDigest
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ContentDigest
    on|off<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>ContentDigest
    off</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host, directory, .htaccess<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> Options<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> experimental<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> ContentDigest is
    only available in Apache 1.1 and later 

    <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>
<pre>
   Content-MD5: AuLb7Dp1rqtRtxz2m9kRpA==
</pre>

    <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 core, and not by any module. For example, SSI documents,
    output from CGI scripts, and byte range responses do not have
    this header.</p>
    <hr />

    <h2><a id="coredumpdirectory"
    name="coredumpdirectory">CoreDumpDirectory directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> CoreDumpDirectory
    <em>directory-path</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> the same location as
    ServerRoot<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>This controls the directory to which Apache attempts to
    switch before dumping core. The default is in the <a
    href="#serverroot">ServerRoot</a> directory, however since this
    should not be writable by the user the server runs as, core
    dumps won't normally get written. If you want a core dump for
    debugging, you can use this directive to place it in a
    different location.</p>

    <p>For example:</p>

    <blockquote>
    <code>CoreDumpDirectory /tmp</code>
    </blockquote>

    <hr />

    <h2><a id="defaulttype" name="defaulttype">DefaultType
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> DefaultType
    <em>MIME-type</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>DefaultType
    text/plain</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host, directory, .htaccess<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> FileInfo<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>There will be times when the server is asked to provide a
    document whose type cannot be determined by its MIME types
    mappings.</p>

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

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

    <p><strong>See also:</strong> <a
    href="mod_mime.html#addtype">AddType</a> and <a
    href="mod_mime.html#typesconfig">TypesConfig</a>.</p>

    <hr />

    <h2><a id="directory" name="directory">&lt;Directory&gt;
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> &lt;Directory
    <em>directory-path</em>&gt; ... &lt;/Directory&gt; <br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Core. 

    <p>&lt;Directory&gt; and &lt;/Directory&gt; are used to enclose
    a group of directives which will apply only to the named
    directory and sub-directories of that directory. Any directive
    which is allowed in a directory context may be used.
    <em>Directory-path</em> is either the full path to a directory,
    or a wild-card string. In a wild-card string, `?' matches any
    single character, and `*' matches any sequences of characters.
    As of Apache 1.3, you may also use `[]' character ranges like
    in the shell. Also as of Apache 1.3 none of the wildcards match
    a `/' character, which more closely mimics the behavior of
    Unix shells. Example:</p>
<pre>
   &lt;Directory /usr/local/httpd/htdocs&gt;
   Options Indexes FollowSymLinks
   &lt;/Directory&gt;
</pre>

    <p><strong>Apache 1.2 and above:</strong> Extended regular
    expressions can also be used, with the addition of the
    <code>~</code> character. For example:</p>
<pre>
   &lt;Directory ~ "^/www/.*/[0-9]{3}"&gt;
</pre>
    would match directories in /www/ that consisted of three
    numbers. 

    <p>If multiple (non-regular expression) directory sections
    match the directory (or 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>

    <blockquote>
      <code>&lt;Directory /&gt;<br />
       AllowOverride None<br />
       &lt;/Directory&gt;<br />
      <br />
       &lt;Directory /home/*&gt;<br />
       AllowOverride FileInfo<br />
       &lt;/Directory&gt;</code>
    </blockquote>
    for access to the document <code>/home/web/dir/doc.html</code>
    the steps are: 

    <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/web</code>).</li>

      <li>Apply any FileInfo directives in
      <code>/home/web/.htaccess</code></li>
    </ul>

    <p>Regular expression directory sections are handled slightly
    differently by Apache 1.2 and 1.3. In Apache 1.2 they are
    interspersed with the normal directory sections and applied in
    the order they appear in the configuration file. They are
    applied only once, and apply when the shortest match possible
    occurs. In Apache 1.3 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>

    <blockquote>
      <code>&lt;Directory ~ abc$&gt;<br />
       ... directives here ...<br />
       &lt;/Directory&gt;<br />
      </code>
    </blockquote>
    Suppose that the filename being accessed is
    <code>/home/abc/public_html/abc/index.html</code>. The server
    considers each of <code>/</code>, <code>/home</code>,
    <code>/home/abc</code>, <code>/home/abc/public_html</code>, and
    <code>/home/abc/public_html/abc</code> in that order. In Apache
    1.2, when <code>/home/abc</code> is considered, the regular
    expression will match and be applied. In Apache 1.3 the regular
    expression isn't considered at all at that point in the tree.
    It won't be considered until after all normal
    &lt;Directory&gt;s and <code>.htaccess</code> files have been
    applied. Then the regular expression will match on
    <code>/home/abc/public_html/abc</code> and be applied. 

    <p><strong>Note that the default Apache access for
    &lt;Directory /&gt; is <samp>Allow from All</samp>. 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>
<pre>
 &lt;Directory /&gt;
     Order Deny,Allow
     Deny from All
 &lt;/Directory&gt;
</pre>

    <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>
    The directory sections typically occur in the access.conf file,
    but they may appear in any configuration file.
    &lt;Directory&gt; directives cannot nest, and cannot appear in
    a <a href="#limit">&lt;Limit&gt;</a> or <a
    href="#limitexcept">&lt;LimitExcept&gt;</a> section. 

    <p><strong>See also</strong>: <a href="../sections.html">How
    Directory, Location and Files sections work</a> for an
    explanation of how these different sections are combined when a
    request is received</p>
    <p><strong>See also</strong>: <a
    href="#directorymatch">DirectoryMatch</a></p>
    <hr />

    <h2><a id="directorymatch"
    name="directorymatch">&lt;DirectoryMatch&gt;</a></h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> &lt;DirectoryMatch
    <em>regex</em>&gt; ... &lt;/DirectoryMatch&gt; <br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Core.<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> Available in
    Apache 1.3 and later 

    <p>&lt;DirectoryMatch&gt; and &lt;/DirectoryMatch&gt; 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 <a href="#directory">&lt;Directory&gt;</a>. However, it
    takes as an argument a regular expression. For example:</p>
<pre>
   &lt;DirectoryMatch "^/www/.*/[0-9]{3}"&gt;
</pre>

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

    <p><strong>See Also:</strong> <a
    href="#directory">&lt;Directory&gt;</a> for a description of
    how regular expressions are mixed in with normal
    &lt;Directory&gt;s.<br />
     <strong>See also</strong>: <a href="../sections.html">How
    Directory, Location and Files sections work</a> for an
    explanation of how these different sections are combined when a
    request is received</p>
    <hr />

    <h2><a id="documentroot" name="documentroot">DocumentRoot
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> DocumentRoot
    <em>directory-path</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>DocumentRoot
    /usr/local/apache/htdocs</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>This directive sets the directory from which httpd will
    serve files. Unless matched by a directive like Alias, the
    server appends the path from the requested URL to the document
    root to make the path to the document. Example:</p>

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

    <p>There appears to be a bug in mod_dir which causes problems
    when the DocumentRoot has a trailing slash (<em>i.e.</em>,
    "DocumentRoot /usr/web/") so please avoid that.</p>
    <hr />

    <h2><a id="ebcdicconvert"
    name="ebcdicconvert">EBCDICConvert</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> EBCDICConvert
    On|Off[=<em>direction</em>] <em>extension</em>
    [<em>extension</em>] ...<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host, directory, .htaccess<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> FileInfo<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> The configurable
    EBCDIC conversion is only available in Apache 1.3.19 and later,
    and on EBCDIC based platforms. 

    <p>The EBCDICConvert directive maps the given filename
    extensions to the specified conversion setting (<samp>On</samp>
    or <samp>Off</samp>). File extensions may be specified with or
    without a leading dot.</p>

    <p>If the optional format <samp>On=<i>direction</i></samp> (or
    <samp>Off=<i>direction</i></samp>) is used, where
    <i>direction</i> is one of <samp>In</samp>, <samp>Out</samp> or
    <samp>InOut</samp>, then the directive only applies to the
    specified transfer direction (<samp>In</samp>: uploaded content
    in a PUT or POST request, <samp>Out</samp>: returned content in
    a GET or POST request, and <samp>InOut</samp>: conversion in
    both directions).<br />
     Otherwise, <samp>InOut</samp> (conversion in both directions)
    is implied.</p>

    <p>Conversion configuration based on file extension is tested
    prior to configuration based on MIME type, to allow for generic
    MIME based rules to be overridden by a more specific file
    extension (several file extensions may exist for the same MIME
    type).</p>

    <p><strong>Example</strong>:<br />
     With a configuration like the following, the normal
    <samp>*.html</samp> files contain HTML text in EBCDIC encoding,
    while <samp>*.ahtml</samp> files contain HTML text in ASCII
    encoding:</p>
<pre>
    # *.html and *.ahtml contain HTML text:
    AddType  text/html  .html .ahtml

    # *.ahtml is not converted (contains ASCII text already):
    EBCDICConvert       Off .ahtml

    # All other text/html files presumably contain EBCDIC text:
    EBCDICConvertByType On  text/html
</pre>
    <br />
     <br />
     

    <p><strong>See also</strong>: <a
    href="#ebcdicconvertbytype">EBCDICConvertByType</a> and <a
    href="../ebcdic.html#ebcdic">Overview of the EBCDIC Conversion
    Functions</a></p>
    <hr />

    <h2><a id="ebcdicconvertbytype"
    name="ebcdicconvertbytype">EBCDICConvertByType</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> EBCDICConvertByType
    On|Off[=<em>direction</em>] <em>mimetype</em>
    [<em>mimetype</em>] ...<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host, directory, .htaccess<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> FileInfo<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> The configurable
    EBCDIC conversion is only available in Apache 1.3.19 and later,
    and on EBCDIC based platforms. 

    <p>The EBCDICConvertByType directive maps the given MIME type
    (optionally containing wildcards) to the specified conversion
    setting (<samp>On</samp> or <samp>Off</samp>).</p>

    <p>If the optional format <samp>On=<i>direction</i></samp> (or
    <samp>Off=<i>direction</i></samp>) is used, where
    <i>direction</i> is one of <samp>In</samp>, <samp>Out</samp> or
    <samp>InOut</samp>, then the directive only applies to the
    specified transfer direction (<samp>In</samp>: uploaded content
    in a PUT or POST request, <samp>Out</samp>: returned content in
    a GET or POST request, and <samp>InOut</samp>: conversion in
    both directions).<br />
     Otherwise, <samp>InOut</samp> (conversion in both directions)
    is implied.</p>

    <p><strong>Example</strong>:<br />
     A useful standard configuration should at least contain the
    following defaults:</p>
<pre>
    # All text documents are stored as EBCDIC files:
    EBCDICConvertByType On  text/* message/* multipart/*
    EBCDICConvertByType On  application/x-www-form-urlencoded \
                model/vrml application/postscript
    # All other files are assumed to be binary:
    EBCDICConvertByType Off */*
</pre>
    If you serve ASCII documents only, for example from an NFS
    mounted unix server, use: 
<pre>
    # All documents are ASCII already:
    EBCDICConvertByType Off */*
</pre>

    <p><strong>See also</strong>: <a
    href="#ebcdicconvert">EBCDICConvert</a> and <a
    href="../ebcdic.html#ebcdic">Overview of the EBCDIC Conversion
    Functions</a></p>
    <hr />

    <h2><a id="ebcdickludge"
    name="ebcdickludge">EBCDICKludge</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> EBCDICKludge
    On|Off<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>EBCDICKludge
    Off</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host, directory, .htaccess<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> FileInfo<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> EBCDICKludge is
    only available in Apache 1.3.19 and later, and on EBCDIC based
    platforms. It is deprecated and will be withdrawn in a future
    version.<br />
     

    <p>The EBCDICKludge is provided for the backward compatible
    behavior with apache versions 1.3.0 through 1.3.18. In these
    versions, all files with MIME types starting with "text/",
    "message/" or "multipart/" or with type
    "application/x-www-form-urlencoded" would be converted by
    default, all other documents were returned unconverted. Only if
    a MIME type "<samp>text/<b>x-ascii-</b><i>subtype</i></samp>"
    was configured for a certain document, the document was assumed
    to be in ASCII format already, and was not converted again.
    Instead, the "<samp><b>x-ascii-</b></samp>" was removed from
    the type, resulting in the MIME type
    "<samp>text/<i>subtype</i></samp>" being returned for the
    document.</p>

    <p>If the EBCDICKludge directive is set to <samp>On</samp>, and
    if none of the file extensions configured with the <a
    href="#ebcdicconvert">EBCDICConvert</a> directive matches in
    the current context, then the server tests for a MIME type of
    the format
    <samp><i>type/</i><b>x-ascii-</b><i>subtype</i></samp>. If the
    document has such a type, then the
    "<samp><b>x-ascii-</b></samp>" substring is removed and the
    conversion set to <samp>Off</samp>. This allows for overriding
    the implicit assumption that all text files are stored in
    EBCDIC format, for example when serving documents from an NFS
    mounted directory with ASCII documents.<br />
     By using the EBCDICKludge, there is no way to force one of the
    other MIME types (<em>e.g.</em>, model/vrml) to be treated as
    an EBCDIC text file. Use of the <a
    href="#ebcdicconvertbytype">EBCDICConvertByType</a> directive
    mentioned above is the preferred way to configure such a
    conversion. (Before Apache version 1.3.19, there was no way at
    all to force these binary documents to be treated as EBCDIC
    text files.)</p>

    <p><strong>See also</strong>: <a
    href="#ebcdicconvert">EBCDICConvert</a>, <a
    href="#ebcdicconvertbytype">EBCDICConvertByType</a> and <a
    href="../ebcdic.html#ebcdic">Overview of the EBCDIC Conversion
    Functions</a></p>
    <hr />

    <h2><a id="errordocument" name="errordocument">ErrorDocument
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ErrorDocument
    <em>error-code document</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host, directory, .htaccess<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> FileInfo<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> The directory
    and .htaccess contexts are only available in Apache 1.1 and
    later. 

    <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 <em>URL-path</em> to handle the
      problem/error</li>

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

    <p>The first option is the default, while options 2-4 are
    configured using the <code>ErrorDocument</code> directive,
    which is followed by the HTTP response code and a message or
    URL.</p>

    <p><em>Messages</em> in this context begin with a single
    double-quote character (<code>"</code>), which does not form
    part of the message itself. Apache will sometimes offer
    additional information regarding the problem/error.</p>

    <p>URLs can begin with a slash (/) for local URLs, or be a full
    URL which the client can resolve. Examples:</p>

    <blockquote>
      <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>
    </blockquote>

    <p>Note that when you specify an <code>ErrorDocument</code>
    that points to a remote URL (ie. anything with a method such as
    "http" 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
    "ErrorDocument 401" directive then it must refer to a local
    document.</strong></p>

    <p>See Also: <a href="../custom-error.html">documentation of
    customizable responses.</a> See the <a
    href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html">HTTP
    specification</a> for a complete list of the status codes and their
    meanings.</p>
    <hr />

    <h2><a id="errorlog" name="errorlog">ErrorLog
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ErrorLog
    <em>file-path</em>|syslog[:<em>facility</em>] <br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>ErrorLog
    logs/error_log</code> (Unix)<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>ErrorLog
    logs/error.log</code> (Windows and OS/2)<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>The error log directive sets the name of the file to which
    the server will log any errors it encounters. If the
    <em>file-path</em> does not begin with a slash (/) then it is
    assumed to be relative to the <a
    href="#serverroot">ServerRoot</a>. If the <em>file-path</em>
    begins with a pipe (|) then it is assumed to be a command to
    spawn to handle the error log.</p>

    <p>Examples</p>

    <code>ErrorLog logs/vhost1.error</code><br />
    <code>ErrorLog |/usr/local/bin/errorlog.pl</code>

    <p><strong>Apache 1.3 and above:</strong> 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:</code><em>facility</em> syntax where
    <em>facility</em> can be one of the names usually documented in
    syslog(1).</p>

    <p>For example:</p>

    <code>ErrorLog syslog</code>

    <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 logfiles are stored is writable by
    anyone other than the user that starts the server.</p>

    <p><strong>See also:</strong> <a href="#loglevel">LogLevel</a>
    and <a href="../logs.html">Apache Log Files</a></p>
    <hr />

    <h2><a id="fileetag" name="fileetag">FileETag directive</a></h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> FileETag
    <i>component</i> ...<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host, directory, .htaccess<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> FileInfo<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> only available
    in Apache 1.3.23 versions and later. 

    <p>
    The FileETag directive configures the file attributes that are
    used to create the ETag (entity tag) response header field
    when the document is based on a file.
    (The ETag value is used in cache management to save network
    bandwidth.)  In Apache 1.3.22 and earlier, the ETag value was
    <i>always</i> formed from the file's inode, size, and last-modified
    time (mtime).  The FileETag directive allows you to choose
    which of these -- if any -- should be used.  The recognised
    keywords are:
    </p>
    <dl compact="compact">
     <dt><b>INode</b></dt>
     <dd>The file's i-node number will be included in the calculation</dd>
     <dt><b>MTime</b></dt>
     <dd>The date and time the file was last modified will be included</dd>
     <dt><b>Size</b></dt>
     <dd>The number of bytes in the file will be included</dd>
     <dt><b>All</b></dt>
     <dd>All available fields will be used (equivalent to
      '<code>FileETag&nbsp;INode&nbsp;MTime&nbsp;Size</code>')</dd>
     <dt><b>None</b></dt>
     <dd>If a document is file-based, no ETag field will be included in the
      response</dd>
    </dl>
    <p>
    The INode, MTime, and Size keywords may be prefixed with either '+'
    or '-', 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&nbspMTime&nbsp;Size</code>'.
    </p>
    <hr />

    <h2><a id="files" name="files">&lt;Files&gt; directive</a></h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> &lt;Files
    <em>filename</em>&gt; ... &lt;/Files&gt;<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host, .htaccess<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> only available
    in Apache 1.2 and above. 

    <p>The &lt;Files&gt; directive provides for access control by
    filename. It is comparable to the <a
    href="#directory">&lt;Directory&gt;</a> directive and <a
    href="#location">&lt;Location&gt;</a> directives. It should be
    matched with a &lt;/Files&gt; 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>&lt;Files&gt;</code> sections are processed in
    the order they appear in the configuration file, after the
    &lt;Directory&gt; sections and <code>.htaccess</code> files are
    read, but before &lt;Location&gt; sections. Note that
    &lt;Files&gt; can be nested inside &lt;Directory&gt; sections
    to restrict the portion of the filesystem they apply to.</p>

    <p>The <em>filename</em> argument should include a filename, or
    a wild-card string, where `?' matches any single character, and
    `*' matches any sequences of characters. Extended regular
    expressions can also be used, with the addition of the
    <code>~</code> character. For example:</p>
<pre>
   &lt;Files ~ "\.(gif|jpe?g|png)$"&gt;
</pre>
    would match most common Internet graphics formats. In Apache
    1.3 and later, <a href="#filesmatch">&lt;FilesMatch&gt;</a> is
    preferred, however. 

    <p>Note that unlike <a
    href="#directory"><code>&lt;Directory&gt;</code></a> and <a
    href="#location"><code>&lt;Location&gt;</code></a> sections,
    <code>&lt;Files&gt;</code> sections can be used inside
    .htaccess files. This allows users to control access to their
    own files, at a file-by-file level.
    For example, to password protect a single file within a
    particular directory, you might add the following to your
    <code>.htaccess</code> file:</p>

    <pre>
    &lt;Files admin.cgi&gt;
    Require group admin
    &lt;/Files&gt;</pre>

    <p>Remember that directives apply to subdirectories as well, so this
    will also protect files called <code>admin.cgi</code> in
    subdirectories, unless specifically overridden.</p>

    <p>(See <a href="#require">Require</a> for details on using the
    <code>Require</code> directive</a>)</p>

    <p><strong>See also</strong>: <a href="../sections.html">How
    Directory, Location and Files sections work</a> for an
    explanation of how these different sections are combined when a
    request is received</p>
    <hr />

    <h2><a id="filesmatch"
    name="filesmatch">&lt;FilesMatch&gt;</a></h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> &lt;FilesMatch
    <em>regex</em>&gt; ... &lt;/FilesMatch&gt;<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host, .htaccess<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> only available
    in Apache 1.3 and above. 

    <p>The &lt;FilesMatch&gt; directive provides for access control
    by filename, just as the <a href="#files">&lt;Files&gt;</a>
    directive does. However, it accepts a regular expression. For
    example:</p>
<pre>
   &lt;FilesMatch "\.(gif|jpe?g|png)$"&gt;
</pre>

    <p>would match most common Internet graphics formats.</p>
    <strong>See also</strong>: <a href="../sections.html">How
    Directory, Location and Files sections work</a> for an
    explanation of how these different sections are combined when a
    request is received 
    <hr />

    <h2><a id="group" name="group">Group directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> Group
    <em>unix-group</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>Group
    #-1</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>The Group directive sets the group under which the server
    will answer requests. In order to use this directive, the
    stand-alone server must be run initially as root.
    <em>Unix-group</em> is one of:</p>

    <dl>
      <dt>A group name</dt>

      <dd>Refers to the given group by name.</dd>

      <dt># followed by a group number.</dt>

      <dd>Refers to a group by its number.</dd>
    </dl>
    It is recommended that you set up a new group specifically for
    running the server. Some admins use user <code>nobody</code>,
    but this is not always possible or desirable. 

    <p>Note: if you start the server as a non-root user, it will
    fail to change to the specified group, and will instead
    continue to run as the group of the original user.</p>

    <p>Special note: Use of this directive in &lt;VirtualHost&gt;
    requires a properly configured <a href="../suexec.html">suEXEC
    wrapper</a>. When used inside a &lt;VirtualHost&gt; in this
    manner, only the group that CGIs are run as is affected.
    Non-CGI requests are still processed as the group specified in
    the main Group directive.</p>

    <p>SECURITY: See <a href="#user">User</a> for a discussion of
    the security considerations.</p>
    <hr />

    <h2><a id="hostnamelookups"
    name="hostnamelookups">HostnameLookups directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> HostnameLookups
    on|off|double<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>HostnameLookups
    off</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host, directory<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a>
    <code>double</code> available only in Apache 1.3 and
    above.<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> Default was
    <code>on</code> prior to Apache 1.3. 

    <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. 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 <a
    href="mod_access.html">mod_access</a> 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 for this directive was previously
    <code>on</code> in versions of Apache prior to 1.3. It was
    changed to <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 <a
    href="../programs/logresolve.html">logresolve</a>, provided in
    the <em>/support</em> directory, can be used to look up host
    names from logged IP addresses offline.</p>
    <hr />

    <h2><a id="identitycheck" name="identitycheck">IdentityCheck
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> IdentityCheck
    on|off<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>IdentityCheck
    off</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host, directory<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>This directive enables RFC1413-compliant logging of the
    remote user name for each connection, where the client machine
    runs identd or something similar. This information is logged in
    the access log. <em>Boolean</em> is either <code>on</code> or
    <code>off</code>.</p>

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

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

    <h2><a id="ifdefine" name="ifdefine">&lt;IfDefine&gt;
    directive</a></h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> &lt;IfDefine
    [!]<em>parameter-name</em>&gt; <em>...</em>
    &lt;/IfDefine&gt;<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> None<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> all<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> &lt;IfDefine&gt;
    is only available in 1.3.1 and later. 

    <p>The &lt;IfDefine <em>test</em>&gt;...&lt;/IfDefine&gt;
    section is used to mark directives that are conditional. The
    directives within an IfDefine section are only processed if the
    <em>test</em> is true. If <em>test</em> is false, everything
    between the start and end markers is ignored.</p>

    <p>The <em>test</em> in the &lt;IfDefine&gt; section directive
    can be one of two forms:</p>

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

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

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

    <p>The <em>parameter-name</em> argument is a define as given on
    the <code>httpd</code> command line via
    <code>-D</code><em>parameter-</em>, at the time the server was
    started.</p>

    <p>&lt;IfDefine&gt; sections are nest-able, which can be used
    to implement simple multiple-parameter tests. Example:</p>
<pre>
  $ httpd -DReverseProxy ...

  # httpd.conf
  &lt;IfDefine ReverseProxy&gt;
  LoadModule rewrite_module libexec/mod_rewrite.so
  LoadModule proxy_module   libexec/libproxy.so
  &lt;/IfDefine&gt;
</pre>
    <hr />

    <h2><a id="ifmodule" name="ifmodule">&lt;IfModule&gt;
    directive</a></h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> &lt;IfModule
    [!]<em>module-name</em>&gt; <em>...</em>
    &lt;/IfModule&gt;<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> None<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> all<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> IfModule is only
    available in 1.2 and later. 

    <p>The &lt;IfModule <em>test</em>&gt;...&lt;/IfModule&gt;
    section is used to mark directives that are conditional. The
    directives within an IfModule section are only processed if the
    <em>test</em> is true. If <em>test</em> is false, everything
    between the start and end markers is ignored.</p>

    <p>The <em>test</em> in the &lt;IfModule&gt; section directive
    can be one of two forms:</p>

    <ul>
      <li><em>module name</em></li>

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

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

    <p>The <em>module name</em> argument is the file name of the
    module, at the time it was compiled.
    For example, <code>mod_rewrite.c</code>.</p>

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

    <h2><a id="include" name="include">Include directive</a></h2>
    <strong>Syntax:</strong> Include
    <em>file-path</em>|<em>directory-path</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> Include is only
    available in Apache 1.3 and later. 

    <p>This directive allows inclusion of other configuration files
    from within the server configuration files.</p>

    <p>The file path specified may be a fully qualified path (i.e.
    starting with a slash), or may be relative to the
    <code>ServerRoot</code> directory.</p>

    <p>New in Apache 1.3.13 is the feature that if
    <code>Include</code> points to a directory, rather than a file,
    Apache will read all files in that directory, and any
    subdirectory, and parse those as configuration files.</p>

    <p>Examples:</p>

    <blockquote>
    <code>Include /usr/local/apache/conf/ssl.conf<br />
    Include /usr/local/apache/conf/vhosts/
    </code>
    </blockquote>

    <p>Or, providing paths relative to your <code>ServerRoot</code>
    directory:</p>

    <blockquote>
    <code>Include conf/ssl.conf<br />
    Include conf/vhosts/
    </code>
    </blockquote>

    <p>Make sure that an included directory does not contain any stray
    files, such as editor temporary files, for example, as Apache will
    attempt to read them in and use the contents as configuration
    directives, which may cause the server to fail on start up.
    Running <code>apachectl configtest</code> will give you a list of
    the files that are being processed during the configuration  
    check:<p>

<pre>
root@host# apachectl configtest
 Processing config directory: /usr/local/apache/conf/vhosts
 Processing config file: /usr/local/apache/conf/vhosts/vhost1
 Processing config file: /usr/local/apache/conf/vhosts/vhost2
Syntax OK
</pre>

    <p>This will help in verifying that you are getting only the files
    that you intended as part of your configuration.</p>

    <p><strong>See also</strong>: <a
    href="../programs/apachectl.html">apachectl</a></p>

    <hr />

    <h2><a id="keepalive" name="keepalive">KeepAlive
    directive</a></h2>
    <strong>Syntax: (Apache 1.1)</strong> KeepAlive
    <em>max-requests</em><br />
     <strong>Default: (Apache 1.1)</strong> <code>KeepAlive
    5</code><br />
     <strong>Syntax: (Apache 1.2)</strong> KeepAlive on|off<br />
     <strong>Default: (Apache 1.2)</strong> <code>KeepAlive
    On</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> KeepAlive is
    only available in Apache 1.1 and later. 

    <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 in Apache 1.2 and
    later, 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>

    <p><strong>Apache 1.1 only</strong>: Set <em>max-requests</em>
    to the maximum number of requests you want Apache to entertain
    per connection. A limit is imposed to prevent a client from
    hogging your server resources. Set this to <code>0</code> to
    disable support. In Apache 1.2 and 1.3, this is controlled
    through the MaxKeepAliveRequests directive instead.</p>

    <p>See also <a
    href="#maxkeepaliverequests">MaxKeepAliveRequests</a>.</p>
    <hr />

    <h2><a id="keepalivetimeout"
    name="keepalivetimeout">KeepAliveTimeout directive</a></h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> KeepAliveTimeout
    <em>seconds</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>KeepAliveTimeout
    15</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> KeepAliveTimeout
    is only available in Apache 1.1 and later. 

    <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 <a
    href="#timeout"><code>Timeout</code></a> directive applies.</p>

    <p>Setting <code>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>
    <hr />

    <h2><a id="limit" name="limit">&lt;Limit&gt; directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> &lt;Limit
    <em>method</em> [<em>method</em>] ... &gt; ...
    &lt;/Limit&gt;<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> any<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <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>&lt;limit&gt;</code> section.</strong></p>

    <p>The purpose of the &lt;Limit&gt; 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 &lt;Limit&gt; bracket <strong>will have no
    effect</strong>. The following example applies the access
    control only to the methods POST, PUT, and DELETE, leaving all
    other methods unprotected:</p>

    <blockquote>
      <code>&lt;Limit POST PUT DELETE&gt;<br />
       Require valid-user<br />
       &lt;/Limit&gt;</code>
    </blockquote>
    The method names listed can be one or more of: GET, POST, PUT,
    DELETE, CONNECT, OPTIONS, TRACE, PATCH, PROPFIND, PROPPATCH,
    MKCOL, COPY, MOVE, LOCK, and UNLOCK. <strong>The method name is
    case-sensitive.</strong> If GET is used it will also restrict
    HEAD requests. 
    <hr />

    <h2><a id="limitexcept" name="limitexcept">&lt;LimitExcept&gt;
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> &lt;LimitExcept
    <em>method</em> [<em>method</em>] ... &gt; ...
    &lt;/LimitExcept&gt;<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> any<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> Available in
    Apache 1.3.5 and later 

    <p>&lt;LimitExcept&gt; and &lt;/LimitExcept&gt; 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; <em>i.e.</em>, it is the opposite of a <a
    href="#limit">&lt;Limit&gt;</a> section and can be used to
    control both standard and nonstandard/unrecognized methods. See
    the documentation for <a href="#limit">&lt;Limit&gt;</a> for
    more details.</p>

    <p>For example:</p>

    <pre>
    &lt;LimitExcept POST GET&gt;
    Require valid-user
    &lt;/LimitExcept&gt;
    </pre>

    <hr />

    <h2><a id="limitrequestbody"
    name="limitrequestbody">LimitRequestBody directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> LimitRequestBody
    <em>bytes</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>LimitRequestBody
    0</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host, directory, .htaccess<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> LimitRequestBody
    is only available in Apache 1.3.2 and later. 

    <p>This directive specifies the number of <em>bytes</em> from 0
    (meaning unlimited) to 2147483647 (2GB) that are allowed in a
    request body. The default value is defined by the compile-time
    constant <code>DEFAULT_LIMIT_REQUEST_BODY</code> (0 as
    distributed).</p>

    <p>The LimitRequestBody 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 passing form information to
    the server. Implementations of the PUT 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 wich to limit the size of the uploaded file to 100K,
    you might use the following directive:</p>

    <pre>LimitRequestBody 102400</pre>
    
    <hr />

    <h2><a id="limitrequestfields"
    name="limitrequestfields">LimitRequestFields directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> LimitRequestFields
    <em>number</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a>
    <code>LimitRequestFields 100</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a>
    LimitRequestFields is only available in Apache 1.3.2 and later.
    

    <p><em>Number</em> 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 LimitRequestFields 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>

    <pre>LimitRequestFields 50</pre>

    <hr />

    <h2><a id="limitrequestfieldsize"
    name="limitrequestfieldsize">LimitRequestFieldsize
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> LimitRequestFieldsize
    <em>bytes</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a>
    <code>LimitRequestFieldsize 8190</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a>
    LimitRequestFieldsize is only available in Apache 1.3.2 and
    later. 

    <p>This directive specifies the number of <em>bytes</em> from 0
    to the value of the compile-time constant
    <code>DEFAULT_LIMIT_REQUEST_FIELDSIZE</code> (8190 as
    distributed) that will be allowed in an HTTP request
    header.</p>

    <p>The LimitRequestFieldsize directive allows the server
    administrator to reduce the limit on the allowed size of an
    HTTP request header field below the normal input buffer size
    compiled with the server. 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.</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>

    <pre>LimitRequestFieldSize 16380</pre>

    <p>Under normal conditions, the value should not be changed from
    the default.</p>
    <hr />

    <h2><a id="limitrequestline"
    name="limitrequestline">LimitRequestLine directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> LimitRequestLine
    <em>bytes</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>LimitRequestLine
    8190</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> LimitRequestLine
    is only available in Apache 1.3.2 and later. 

    <p>This directive sets the number of <em>bytes</em> from 0 to
    the value of the compile-time constant
    <code>DEFAULT_LIMIT_REQUEST_LINE</code> (8190 as distributed)
    that will be allowed on the HTTP request-line.</p>

    <p>The LimitRequestLine directive allows the server
    administrator to reduce the limit on the allowed size of a
    client's HTTP request-line below the normal input buffer size
    compiled with the server. Since the request-line consists of
    the HTTP method, URI, and protocol version, the
    LimitRequestLine 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 GET 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>

    <pre>LimitRequestLine 16380</pre>

    <p>Under normal conditions, the value should not be changed from
    the default.</p>
    <hr />

    <h2><a id="listen" name="listen">Listen directive</a></h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> Listen
    [<em>IP-address</em>:]<em>port</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> Listen is only
    available in Apache 1.1 and later. 

    <p>The Listen directive instructs Apache to listen to more than
    one IP address or port; by default it responds to requests on
    all IP interfaces, but only on the port given by the <code><a
    href="#port">Port</a></code> directive.</p>
    <tt>Listen</tt> can be used instead of <tt><a
    href="#bindaddress">BindAddress</a></tt> and <tt>Port</tt>. It
    tells the server to accept incoming requests on the specified
    port or address-and-port combination. If the first format is
    used, with a port number only, the server listens to the given
    port on all interfaces, instead of the port given by the
    <tt>Port</tt> directive. If an IP address is given as well as a
    port, the server will listen on the given port and interface. 

    <p>Note that you may still require a <tt>Port</tt> directive so
    that URLs that Apache generates that point to your server still
    work.</p>

    <p>Multiple Listen directives may be used to specify a number
    of addresses and ports to listen to. The server will respond to
    requests from any of the listed addresses and ports.</p>

    <p>For example, to make the server accept connections on both
    port 80 and port 8000, use:</p>
<pre>
   Listen 80
   Listen 8000
</pre>
    To make the server accept connections on two specified
    interfaces and port numbers, use 
<pre>
   Listen 192.170.2.1:80
   Listen 192.170.2.5:8000
</pre>

    <p><strong>See Also:</strong> <a href="../dns-caveats.html">DNS
    Issues</a><br />
     <strong>See Also:</strong> <a href="../bind.html">Setting
    which addresses and ports Apache uses</a><br />
     <strong>See Also:</strong> <a
    href="http://www.apache.org/info/known_bugs.html#listenbug">Known
    Bugs</a></p>
    <hr />

    <h2><a id="listenbacklog" name="listenbacklog">ListenBacklog
    directive</a></h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ListenBacklog
    <em>backlog</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>ListenBacklog
    511</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> ListenBacklog is
    only available in Apache versions after 1.2.0. 

    <p>The maximum length of the queue of pending connections.
    Generally no tuning is needed or desired, however on some
    systems it is desirable to increase this when under a TCP SYN
    flood attack. See the backlog parameter to the
    <code>listen(2)</code> system call.</p>

    <p>This will often be limited to a smaller number by the
    operating system. This varies from OS to OS. Also note that
    many OSes do not use exactly what is specified as the backlog,
    but use a number based on (but normally larger than) what is
    set.</p>
    <hr />

    <h2><a id="location" name="location">&lt;Location&gt;
    directive</a></h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> &lt;Location
    <em>URL-path</em>|<em>URL</em>&gt; ... &lt;/Location&gt;<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> Location is only
    available in Apache 1.1 and later. 

    <p>The &lt;Location&gt; directive provides for access control
    by URL. It is similar to the <a
    href="#directory">&lt;Directory&gt;</a> directive, and starts a
    subsection which is terminated with a &lt;/Location&gt;
    directive. <code>&lt;Location&gt;</code> sections are processed
    in the order they appear in the configuration file, after the
    &lt;Directory&gt; sections and <code>.htaccess</code> files are
    read, and after the &lt;Files&gt; sections.</p>

    <p>Note that URLs do not have to line up with the filesystem at
    all, it should be emphasized that &lt;Location&gt; operates
    completely outside the filesystem.</p>

    <p>For all origin (non-proxy) requests, the URL to be matched
    is of the form <code>/path/</code>, and you should not include
    any <code>http://servername</code> prefix. 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, `?' matches
    any single character, and `*' matches any sequences of
    characters.</p>

    <p><strong>Apache 1.2 and above:</strong> Extended regular
    expressions can also be used, with the addition of the
    <code>~</code> character. For example:</p>
<pre>
   &lt;Location ~ "/(extra|special)/data"&gt;
</pre>

    <p>would match URLs that contained the substring "/extra/data"
    or "/special/data". In Apache 1.3 and above, a new directive <a
    href="#locationmatch">&lt;LocationMatch&gt;</a> exists which
    behaves identical to the regex version of
    <code>&lt;Location&gt;</code>.</p>

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

    <p><strong>Apache 1.3 and above note about / (slash)</strong>:
    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>&lt;LocationMatch&gt;</code> directive and the
    regex version of <code>&lt;Location&gt;</code> require you to
    explicitly specify multiple slashes if that is your intention.
    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>&lt;Location&gt;</code> directive behaves similarly when
    used for proxy requests. But when (non-regex)
    <code>&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>

    <p><strong>See also</strong>: <a href="../sections.html">How
    Directory, Location and Files sections work</a> for an
    explanation of how these different sections are combined when a
    request is received</p>
    <hr />

    <h2><a id="locationmatch"
    name="locationmatch">&lt;LocationMatch&gt;</a></h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> &lt;LocationMatch
    <em>regex</em>&gt; ... &lt;/LocationMatch&gt;<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> LocationMatch is
    only available in Apache 1.3 and later. 

    <p>The &lt;LocationMatch&gt; directive provides for access
    control by URL, in an identical manner to <a
    href="#location">&lt;Location&gt;</a>. However, it takes a
    regular expression as an argument instead of a simple string.
    For example:</p>
<pre>
   &lt;LocationMatch "/(extra|special)/data"&gt;
</pre>

    <p>would match URLs that contained the substring "/extra/data"
    or "/special/data".</p>
    <strong>See also</strong>: <a href="../sections.html">How
    Directory, Location and Files sections work</a> for an
    explanation of how these different sections are combined when a
    request is received 
    <hr />

    <h2><a id="lockfile" name="lockfile">LockFile
    directive</a></h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> LockFile
    <em>file-path</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>LockFile
    logs/accept.lock</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>The LockFile directive sets the path to the lockfile used
    when Apache is compiled with either USE_FCNTL_SERIALIZED_ACCEPT
    or USE_FLOCK_SERIALIZED_ACCEPT. This directive should normally
    be left at its default value. The main reason for changing it
    is if the <code>logs</code> directory is NFS mounted, since
    <strong>the lockfile must be stored on a local disk</strong>.
    The PID of the main server process is automatically appended to
    the filename.</p>

    <p><strong>SECURITY:</strong> It is best to avoid putting this
    file in a world writable directory such as
    <code>/var/tmp</code> because someone could create a denial of
    service attack and prevent the server from starting by creating
    a lockfile with the same name as the one the server will try to
    create.</p>
    <hr />

    <h2><a id="loglevel" name="loglevel">LogLevel
    directive</a></h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> LogLevel
    <em>level</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>LogLevel
    warn</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> LogLevel is only
    available in 1.3 or later. 

    <p>LogLevel adjusts the verbosity of the messages recorded in
    the error logs (see <a href="#errorlog">ErrorLog</a>
    directive). The following <em>level</em>s are available, in
    order of decreasing significance:</p>

    <table>
      <tr>
        <th align="LEFT"><strong>Level</strong> </th>

        <th align="LEFT"><strong>Description</strong> </th>
        <th align="LEFT"><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>

    <pre>LogLevel notice</pre>

    <hr />

    <h2><a id="maxclients" name="maxclients">MaxClients
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> MaxClients
    <em>number</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>MaxClients
    256</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>The MaxClients directive sets the limit on the number of
    simultaneous requests that can be supported; not more than this
    number of child server processes will be created. To configure
    more than 256 clients, you must edit the HARD_SERVER_LIMIT
    entry in httpd.h and recompile.</p>

    <p>Any connection attempts over the MaxClients limit will
    normally be queued, up to a number based on the <a
    href="#listenbacklog">ListenBacklog</a> directive. Once a child
    process is freed at the end of a different request, the
    connection will then be serviced.</p>
    <hr />

    <h2><a id="maxkeepaliverequests"
    name="maxkeepaliverequests">MaxKeepAliveRequests
    directive</a></h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> MaxKeepAliveRequests
    <em>number</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a>
    <code>MaxKeepAliveRequests 100</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> Only available
    in Apache 1.2 and later. 

    <p>The MaxKeepAliveRequests directive limits the number of
    requests allowed per connection when <a
    href="#keepalive">KeepAlive</a> 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. In Apache 1.1, this is controlled through
    an option to the KeepAlive directive.</p>

    <p>For example</p>

    <pre>MaxKeepAliveRequests 500</pre>

    <hr />

    <h2><a id="maxrequestsperchild"
    name="maxrequestsperchild">MaxRequestsPerChild
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> MaxRequestsPerChild
    <em>number</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a>
    <code>MaxRequestsPerChild 0</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>The MaxRequestsPerChild directive sets the limit on the
    number of requests that an individual child server process will
    handle. After MaxRequestsPerChild requests, the child process
    will die. If MaxRequestsPerChild is 0, then the process will
    never expire.</p>

    <p>Setting MaxRequestsPerChild to a non-zero limit has two
    beneficial effects:</p>

    <ul>
      <li>it limits the amount of memory that process can consume
      by (accidental) memory leakage;</li>

      <li>by giving processes a finite lifetime, it helps reduce
      the number of processes when the server load reduces.</li>
    </ul>

    <p>However, on Win32, It is recommended that this be set to 0.
    If it is set to a non-zero value, when the request count is
    reached, the child process exits, and is respawned, at which
    time it re-reads the configuration files. This can lead to
    unexpected behavior if you have modified a configuration file,
    but are not expecting the changes to be applied yet. See also
    <a href="#threadsperchild">ThreadsPerChild</a>.</p>

    <p><strong>NOTE:</strong> For <em>KeepAlive</em> requests, only
    the first request is counted towards this limit. In effect, it
    changes the behavior to limit the number of
    <em>connections</em> per child.</p>
    <hr />

    <h2><a id="maxspareservers"
    name="maxspareservers">MaxSpareServers directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> MaxSpareServers
    <em>number</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>MaxSpareServers
    10</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>The MaxSpareServers directive sets the desired maximum
    number of <em>idle</em> child server processes. An idle process
    is one which is not handling a request. If there are more than
    MaxSpareServers idle, then the parent process will kill off the
    excess processes.</p>

    <p>Tuning of this parameter should only be necessary on very
    busy sites. Setting this parameter to a large number is almost
    always a bad idea.</p>

    <p>Note that this is the maximum number of <em>spare</em> servers,
    not the maximum total number of client requests that can be handled
    at one time. If you wish to limit that number, see the <a
    href="#maxclients">MaxClients</a> directive.</p>

    <p>This directive has no effect when used with the Apache Web
    server on a Microsoft Windows platform.</p>

    <p>See also <a href="#minspareservers">MinSpareServers</a>,
    <a href="#startservers">StartServers</a>, and <a
    href="#maxclients">MaxClients</a>.</p>
    <hr />

    <h2><a id="minspareservers"
    name="minspareservers">MinSpareServers directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> MinSpareServers
    <em>number</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>MinSpareServers
    5</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>The MinSpareServers directive sets the desired minimum
    number of <em>idle</em> child server processes. An idle process
    is one which is not handling a request. If there are fewer than
    MinSpareServers idle, then the parent process creates new
    children at a maximum rate of 1 per second.</p>

    <p>Tuning of this parameter should only be necessary on very
    busy sites. Setting this parameter to a large number is almost
    always a bad idea.</p>

    <p>Note that setting this directive to some value <i>m</i> ensures
    that you will always have at least <i>n + m</i> <code>httpd</code>
    processes running when you have <i>n</i> active client requests.</p>

    <p>This directive has no effect on Microsoft Windows.</p>

    <p>See also <a href="#maxspareservers">MaxSpareServers</a>,
    <a href="#startservers">StartServers</a>, and <a
    href="#maxclients">MaxClients</a>.</p>
    <hr />

    <h2><a id="namevirtualhost"
    name="namevirtualhost">NameVirtualHost directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> NameVirtualHost
    <em>addr</em>[:<em>port</em>]<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> NameVirtualHost
    is only available in Apache 1.3 and later 

    <p>The NameVirtualHost directive is a required directive if you
    want to configure <a href="../vhosts/">name-based virtual
    hosts</a>.</p>

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

    <blockquote>
      <code>NameVirtualHost 111.22.33.44</code>
    </blockquote>
    With the NameVirtualHost 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>Note: the "main server" and any _default_ servers will
    <strong>never</strong> be served for a request to a
    NameVirtualHost IP Address (unless for some reason you specify
    NameVirtualHost but then don't define any VirtualHosts for that
    address).</p>

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

    <blockquote>
      <code>NameVirtualHost 111.22.33.44:8080</code>
    </blockquote>
    In Apache 1.3.13 and greater you can specify a <code>*</code>
    for the <em>addr</em>. This creates a wildcard NameVirtualHost
    which will match connections to any address that isn't
    configured with a more specific NameVirtualHost directive or <a
    href="#virtualhost">&lt;VirtualHost&gt;</a> section. This is
    useful if you want only name-based virtual hosts and you don't
    want to hard-code the server's IP address into the
    configuration file. 

    <p><strong>See also:</strong> <a href="../vhosts/">Apache
    Virtual Host documentation</a></p>
    <hr />

    <h2><a id="options" name="options">Options directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> Options
    [+|-]<em>option</em> [[+|-]<em>option</em>] ...<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host, directory, .htaccess<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> Options<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>The Options directive controls which server features are
    available in a particular directory.</p>

    <p><em>option</em> 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>All</dt>

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

      <dt>ExecCGI</dt>

      <dd>
      Execution of CGI scripts is permitted.</dd>

      <dt>FollowSymLinks</dt>

      <dd>

      The server will follow symbolic links in this
      directory.<br />
       <strong>Note</strong>: even though the server follows the
      symlink it does <em>not</em> change the pathname used to
      match against <code>&lt;Directory&gt;</code> sections.<br />
       <strong>Note</strong>: this option gets ignored if set
      inside a &lt;Location&gt; section.</dd>

      <dt>Includes</dt>

      <dd>
      Server-side includes are permitted.</dd>

      <dt>IncludesNOEXEC</dt>

      <dd>
      
      Server-side includes are permitted, but the #exec command and
      #exec CGI are disabled. It is still possible to #include
      virtual CGI scripts from ScriptAliase'd directories.</dd>

      <dt>Indexes</dt>

      <dd>
      If a URL which maps to a directory is requested, and the
      there is no DirectoryIndex (<em>e.g.</em>, index.html) in
      that directory, then the server will return a formatted
      listing of the directory.</dd>

      <dt>MultiViews</dt>

      <dd>
      <a href="../content-negotiation.html">Content negotiated</a>
      MultiViews are allowed.</dd>

      <dt>SymLinksIfOwnerMatch</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.<br />
       <strong>Note</strong>: this option gets ignored if set
      inside a &lt;Location&gt; section.</dd>
    </dl>
    Normally, if multiple <code>Options</code> could apply to a
    directory, then the most specific one is taken complete; the
    options are not merged. However if <em>all</em> the options on
    the <code>Options</code> directive are preceded by a + or -
    symbol, the options are merged. Any options preceded by a + are
    added to the options currently in force, and any options
    preceded by a - are removed from the options currently in
    force. 

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

    <blockquote>
      <code>&lt;Directory /web/docs&gt;<br />
       Options Indexes FollowSymLinks<br />
       &lt;/Directory&gt;<br />
       &lt;Directory /web/docs/spec&gt;<br />
       Options Includes<br />
       &lt;/Directory&gt;</code>
    </blockquote>
    then only <code>Includes</code> will be set for the
    /web/docs/spec directory. However if the second
    <code>Options</code> directive uses the + and - symbols: 

    <blockquote>
      <code>&lt;Directory /web/docs&gt;<br />
       Options Indexes FollowSymLinks<br />
       &lt;/Directory&gt;<br />
       &lt;Directory /web/docs/spec&gt;<br />
       Options +Includes -Indexes<br />
       &lt;/Directory&gt;</code>
    </blockquote>
    then the options <code>FollowSymLinks</code> and
    <code>Includes</code> are set for the /web/docs/spec directory.
    

    <p><strong>Note:</strong> Using <code>-IncludesNOEXEC</code> or
    <code>-Includes</code> disables server-side includes completely
    regardless of the previous setting.</p>

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

    <h2><a id="pidfile" name="pidfile">PidFile directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> PidFile
    <em>file-path</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>PidFile
    logs/httpd.pid</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>The PidFile directive sets the file to which the server
    records the process id of the daemon. If the filename does not
    begin with a slash (/) then it is assumed to be relative to the
    <a href="#serverroot">ServerRoot</a>. The PidFile is only used
    in <a href="#servertype">standalone</a> mode.</p>

    <p>It is often useful to be able to send the server a signal,
    so that it closes and then reopens its <a
    href="#errorlog">ErrorLog</a> and TransferLog, and re-reads its
    configuration files. This is done by sending a SIGHUP (kill -1)
    signal to the process id listed in the PidFile.</p>

    <p>The PidFile is subject to the same warnings about log file
    placement and <a
    href="../misc/security_tips.html#serverroot">security</a>.</p>
    <hr />

    <h2><a id="port" name="port">Port directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> Port
    <em>number</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>Port
    80</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p><em>Number</em> is a number from 0 to 65535; some port
    numbers (especially below 1024) are reserved for particular
    protocols. See <code>/etc/services</code> for a list of some
    defined ports; the standard port for the http protocol is
    80.</p>

    <p>The Port directive has two behaviors, the first of which is
    necessary for NCSA backwards compatibility (and which is
    confusing in the context of Apache).</p>

    <ul>
      <li>In the absence of any <a href="#listen">Listen</a> or <a
      href="#bindaddress">BindAddress</a> directives specifying a
      port number, a Port directive given in the "main server"
      (<em>i.e.</em>, outside any <a
      href="#virtualhost">&lt;VirtualHost&gt;</a> section) sets the
      network port on which the server listens. If there are any
      Listen or BindAddress directives specifying
      <code>:number</code> then Port has no effect on what address
      the server listens at.</li>

      <li>The Port directive sets the <code>SERVER_PORT</code>
      environment variable (for <a href="mod_cgi.html">CGI</a> and
      <a href="mod_include.html">SSI</a>), and is used when the
      server must generate a URL that refers to itself (for example
      when creating an external redirect to itself). This behavior
      is modified by <a
      href="#usecanonicalname">UseCanonicalName</a>.</li>
    </ul>
    The primary behavior of Port should be considered to be
    similar to that of the <a href="#servername">ServerName</a>
    directive. The ServerName and Port together specify what you
    consider to be the <em>canonical</em> address of the server.
    (See also <a href="#usecanonicalname">UseCanonicalName</a>.) 

    <p>Port 80 is one of Unix's special ports. All ports numbered
    below 1024 are reserved for system use, <em>i.e.</em>, regular
    (non-root) users cannot make use of them; instead they can only
    use higher port numbers. To use port 80, you must start the
    server from the root account. After binding to the port and
    before accepting requests, Apache will change to a low
    privileged user as set by the <a href="#user">User
    directive</a>.</p>

    <p>If you cannot use port 80, choose any other unused port.
    Non-root users will have to choose a port number higher than
    1023, such as 8000.</p>

    <p>SECURITY: if you do start the server as root, be sure not to
    set <a href="#user">User</a> to root. If you run the server as
    root whilst handling connections, your site may be open to a
    major security attack.</p>
    <hr />

    <h2><a id="require" name="require">Require directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> Require
    <em>entity-name</em> [<em>entity-name</em>] ...<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> directory,
    .htaccess<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> AuthConfig<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>This directive selects which authenticated users can access
    a directory. The allowed syntaxes are:</p>

    <ul>
      <li>
        Require user <em>userid</em> [<em>userid</em>] ... 

        <p>Only the named users can access the directory.</p>
      </li>

      <li>
        Require group <em>group-name</em> [<em>group-name</em>] ...
        

        <p>Only users in the named groups can access the
        directory.</p>
      </li>

      <li>
        Require valid-user 

        <p>All valid users can access the directory.</p>
      </li>
    </ul>

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

    <blockquote>
      <code>AuthType Basic<br />
       AuthName "Restricted Directory"<br />
       AuthUserFile /web/users<br />
       AuthGroupFile /web/groups<br />
       Require group admin<br />
      </code>
    </blockquote>
    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>Require</code> statement into a <a
    href="#limit">&lt;Limit&gt;</a> section 

    <p>See also <a href="#satisfy">Satisfy</a> and <a
    href="mod_access.html">mod_access</a>.</p>
    <hr />

    <h2><a id="resourceconfig" name="resourceconfig">ResourceConfig
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ResourceConfig
    <em>file-path</em>|<em>directory-path</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>ResourceConfig
    conf/srm.conf</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core <br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> The ability to
    specify a directory, rather than a file name, is only available in
    Apache 1.3.13 and later.

    <p>The server will read this file for more directives after
    reading the httpd.conf file. <em>File-path</em> is relative to
    the <a href="#serverroot">ServerRoot</a>. This feature can be
    disabled using:</p>

    <blockquote>
      <code>ResourceConfig /dev/null</code>
    </blockquote>
    Or, on Win32 servers, 

    <blockquote>
      <code>ResourceConfig nul</code>
    </blockquote>
    <p>Historically, this file contained most directives except for
    server configuration directives and <a
    href="#directory">&lt;Directory&gt;</a> sections; in fact it
    can now contain any server directive allowed in the <em>server
    config</em> context. However, since Apache version 1.3.4, the
    default <code>srm.conf</code> file which ships with Apache contains
    only comments, and all directives are placed in the main server
    configuration file, <code>httpd.conf</code>.</p>

    <p>If <code>ResourceConfig</code> points to a directory, rather than
    a file, Apache will read all files in that directory, and any
    subdirectory, and parse those as configuration files. Note that
    <emph>any</emph> file in the specified directory will be loaded as a
    configuration file, so make sure that you don't have any stray files
    in this directory by mistake, such as temporary files created by
    your editor, for example.</p>

    <p>See also <a href="#accessconfig">AccessConfig</a>.</p>
    <hr />

    <h2><a id="rlimit" name="rlimit">RLimitCPU</a> <a
    id="rlimitcpu" name="rlimitcpu">directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> RLimitCPU
    <em>number</em>|max [<em>number</em>|max] <br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <em>Unset; uses
    operating system defaults</em> <br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> RLimitCPU is
    only available in Apache 1.2 and later 

    <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 root, 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>

    <p>See also <a href="#rlimitmem">RLimitMEM</a> or <a
    href="#rlimitnproc">RLimitNPROC</a>.</p>
    <hr />

    <h2><a id="rlimitmem" name="rlimitmem">RLimitMEM
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> RLimitMEM
    <em>number</em>|max [<em>number</em>|max]<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <em>Unset; uses
    operating system defaults</em> <br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> RLimitMEM is
    only available in Apache 1.2 and later 

    <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 root, 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>

    <p>See also <a href="#rlimitcpu">RLimitCPU</a> or <a
    href="#rlimitnproc">RLimitNPROC</a>.</p>
    <hr />

    <h2><a id="rlimitnproc" name="rlimitnproc">RLimitNPROC
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> RLimitNPROC
    <em>number</em>|max [<em>number</em>|max]<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <em>Unset; uses
    operating system defaults</em> <br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> RLimitNPROC is
    only available in Apache 1.2 and later 

    <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 root, 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>

    <p>Note: If CGI processes are <strong>not</strong> running
    under userids other than the web server userid, this directive
    will limit the number of processes that the server itself can
    create. Evidence of this situation will be indicated by
    <strong><em>cannot fork</em></strong> messages in the
    error_log.</p>

    <p>See also <a href="#rlimitmem">RLimitMEM</a> or <a
    href="#rlimitcpu">RLimitCPU</a>.</p>
    <hr />

    <h2><a id="satisfy" name="satisfy">Satisfy directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> Satisfy any|all<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> Satisfy all<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> directory,
    .htaccess<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> Satisfy is only
    available in Apache 1.2 and later 

    <p>Access policy if both <code>Allow</code> and
    <code>Require</code> used. The parameter can be either
    <em>'all'</em> or <em>'any'</em>. 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 ("all") is to require that the client
    passes the address access restriction <em>and</em> enters a
    valid username and password. With the "any" 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>See also <a href="#require">Require</a> and <a
    href="mod_access.html#allow">Allow</a>.</p>
    <hr />

    <h2><a id="scoreboardfile" name="scoreboardfile">ScoreBoardFile
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ScoreBoardFile
    <em>file-path</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>ScoreBoardFile
    logs/apache_status</code> <br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>The ScoreBoardFile directive is required on some
    architectures to place a file that the server will use to
    communicate between its children and the parent. The easiest
    way to find out if your architecture requires a scoreboard file
    is to run Apache and see if it creates the file named by the
    directive. If your architecture requires it then you must
    ensure that this file is not used at the same time by more than
    one invocation of Apache.</p>

    <p>If you have to use a ScoreBoardFile then you may see
    improved speed by placing it on a RAM disk. But be careful that
    you heed the same warnings about log file placement and <a
    href="../misc/security_tips.html">security</a>.</p>

    <p>Apache 1.2 and above:</p>

    <p>Linux 1.x users might be able to add <code>-DHAVE_SHMGET
    -DUSE_SHMGET_SCOREBOARD</code> to the <code>EXTRA_CFLAGS</code>
    in your <code>Configuration</code>. This might work with some
    1.x installations, but won't work with all of them. (Prior to
    1.3b4, <code>HAVE_SHMGET</code> would have sufficed.)</p>

    <p>SVR4 users should consider adding <code>-DHAVE_SHMGET
    -DUSE_SHMGET_SCOREBOARD</code> to the <code>EXTRA_CFLAGS</code>
    in your <code>Configuration</code>. This is believed to work,
    but we were unable to test it in time for 1.2 release. (Prior
    to 1.3b4, <code>HAVE_SHMGET</code> would have sufficed.)</p>

    <p><strong>See Also</strong>: <a
    href="../stopping.html">Stopping and Restarting Apache</a></p>
    <hr />

    <h2><a id="scriptinterpretersource"
    name="scriptinterpretersource">ScriptInterpreterSource
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ScriptInterpreterSource
    registry|script<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a>
    <code>ScriptInterpreterSource script</code> <br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> directory,
    .htaccess<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core (Windows only) 

    <p>This directive is used to control how Apache 1.3.5 and later
    finds the interpreter used to run CGI scripts. The default
    technique is to use the interpreter pointed to by the #! line
    in the script. Setting ScriptInterpreterSource registry will
    cause the Windows Registry to be searched using the script file
    extension (e.g., .pl) as a search key.</p>
    <hr />

    <h2><a id="sendbuffersize" name="sendbuffersize">SendBufferSize
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> SendBufferSize
    <em>bytes</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>The server will set the TCP buffer size to the number of
    bytes specified. Very useful to increase past standard OS
    defaults on high speed high latency (<em>i.e.</em>, 100ms or
    so, such as transcontinental fast pipes)</p>
    <hr />

    <h2><a id="serveradmin" name="serveradmin">ServerAdmin
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ServerAdmin
    <em>email-address</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>The ServerAdmin sets the e-mail address that the server
    includes in any error messages it returns to the client.</p>

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

    <blockquote>
      <code>ServerAdmin www-admin@foo.bar.com</code>
    </blockquote>
    as users do not always mention that they are talking about the
    server! 
    <hr />

    <h2><a id="serveralias" name="serveralias">ServerAlias
    directive</a></h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ServerAlias
    <em>hostname</em> [<em>hostname</em>] ...<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> virtual host<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> ServerAlias is
    only available in Apache 1.1 and later. 

    <p>The ServerAlias directive sets the alternate names for a
    host, for use with <a
    href="../vhosts/name-based.html">name-based virtual
    hosts</a>.</p>

    <p>Example:</p>

    <pre>
    &lt;VirtualHost *&gt;
    ServerName server.domain.com
    ServerAlias server server2.domain.com server2
    ...
    &lt;/VirtualHost&gt;
    </pre>

    <p><strong>See also:</strong> <a href="../vhosts/">Apache
    Virtual Host documentation</a></p>
    <hr />

    <h2><a id="servername" name="servername">ServerName
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ServerName
    <em>fully-qualified-domain-name</em> <br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>The ServerName directive sets the hostname of the server;
    this is used when creating redirection URLs. If it is not
    specified, then the server attempts to deduce it from its own
    IP address; however this may not work reliably, or may not
    return the preferred hostname. For example:</p>

    <blockquote>
      <code>ServerName www.example.com</code>
    </blockquote>
    would be used if the canonical (main) name of the actual
    machine were <code>simple.example.com</code>. 

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

    <p><strong>See Also</strong>:<br />
     <a href="../dns-caveats.html">DNS Issues</a><br />
     <a href="../vhosts/">Apache virtual host
    documentation</a><br />
     <a href="#usecanonicalname">UseCanonicalName</a><br />
     <a href="#namevirtualhost">NameVirtualHost</a><br />
     <a href="#serveralias">ServerAlias</a><br />
    </p>
    <hr />

    <h2><a id="serverpath" name="serverpath">ServerPath
    directive</a></h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ServerPath
    <em>directory-path</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> virtual host<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> ServerPath is
    only available in Apache 1.1 and later. 

    <p>The ServerPath directive sets the legacy URL pathname for a
    host, for use with <a href="../vhosts/">name-based virtual
    hosts</a>.</p>

    <p><strong>See also:</strong> <a href="../vhosts/">Apache
    Virtual Host documentation</a></p>
    <hr />

    <h2><a id="serverroot" name="serverroot">ServerRoot
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ServerRoot
    <em>directory-path</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>ServerRoot
    /usr/local/apache</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>The ServerRoot directive sets the directory in which the
    server lives. Typically it will contain the subdirectories
    <code>conf/</code> and <code>logs/</code>. Relative paths for
    other configuration files are taken as relative to this
    directory.</p>

    <p>See also <a href="../invoking.html">the <code>-d</code>
    option to httpd</a>.</p>

    <p>See also <a href="../misc/security_tips.html#serverroot">the
    security tips</a> for information on how to properly set
    permissions on the ServerRoot.</p>
    <hr />

    <h2><a id="serversignature"
    name="serversignature">ServerSignature directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ServerSignature
    On|Off|EMail<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>ServerSignature
    Off</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host, directory, .htaccess<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> ServerSignature
    is only available in Apache 1.3 and later. 

    <p>The ServerSignature directive allows the configuration of a
    trailing footer line under server-generated documents (error
    messages, mod_proxy ftp directory listings, mod_info 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.<br />
     The <samp>Off</samp> setting, which is the default, suppresses
    the error line (and is therefore compatible with the behavior
    of Apache-1.2 and below). The <samp>On</samp> setting simply
    adds a line with the server version number and <a
    href="#servername">ServerName</a> of the serving virtual host,
    and the <samp>EMail</samp> setting additionally creates a
    "mailto:" reference to the <a
    href="#serveradmin">ServerAdmin</a> of the referenced
    document.</p>
    <hr />

    <h2><a id="servertokens" name="servertokens">ServerTokens
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ServerTokens
    Minimal|ProductOnly|OS|Full<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>ServerTokens
    Full</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config <br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> ServerTokens is
    only available in Apache 1.3 and later; the
    <code>ProductOnly</code> keyword is only available in versions
    later than 1.3.12 

    <p>This directive controls whether <samp>Server</samp> 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>): <samp>Server:
      Apache</samp></dd>

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

      <dd>Server sends (<em>e.g.</em>): <samp>Server:
      Apache/1.3.0</samp></dd>

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

      <dd>Server sends (<em>e.g.</em>): <samp>Server: Apache/1.3.0
      (Unix)</samp></dd>

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

      <dd>Server sends (<em>e.g.</em>): <samp>Server: Apache/1.3.0
      (Unix) PHP/3.0 MyMod/1.2</samp></dd>
    </dl>

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

    <h2><a id="servertype" name="servertype">ServerType
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ServerType
    <em>type</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>ServerType
    standalone</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>The ServerType directive sets how the server is executed by
    the system. <em>Type</em> is one of</p>

    <dl>
      <dt>inetd</dt>

      <dd>The server will be run from the system process inetd; the
      command to start the server is added to
      <code>/etc/inetd.conf</code></dd>

      <dt>standalone</dt>

      <dd>The server will run as a daemon process; the command to
      start the server is added to the system startup scripts.
      (<code>/etc/rc.local</code> or
      <code>/etc/rc3.d/...</code>.)</dd>
    </dl>
    Inetd is the lesser used of the two options. For each http
    connection received, a new copy of the server is started from
    scratch; after the connection is complete, this program exits.
    There is a high price to pay per connection, but for security
    reasons, some admins prefer this option. <font
    color="red">Inetd mode is no longer recommended and does not
    always work properly. Avoid it if at all possible.</font> 

    <p>Standalone is the most common setting for ServerType since
    it is far more efficient. The server is started once, and
    services all subsequent connections. If you intend running
    Apache to serve a busy site, standalone will probably be your
    only option.</p>
    <hr />

    <h2><a id="startservers" name="startservers">StartServers
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> StartServers
    <em>number</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>StartServers
    5</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>The StartServers directive sets the number of child server
    processes created on startup. As the number of processes is
    dynamically controlled depending on the load, there is usually
    little reason to adjust this parameter.</p>

    <p>When running under Microsoft Windows, this directive has no
    effect. There is always one child which handles all requests.
    Within the child requests are handled by separate threads. The
    <a href="#threadsperchild">ThreadsPerChild</a> directive
    controls the maximum number of child threads handling requests,
    which will have a similar effect to the setting of
    <samp>StartServers</samp> on Unix.</p>

    <p>See also <a href="#minspareservers">MinSpareServers</a> and
    <a href="#maxspareservers">MaxSpareServers</a>.</p>
    <hr />

    <h2><a id="threadsperchild"
    name="threadsperchild">ThreadsPerChild</a></h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ThreadsPerChild
    <em>number</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>ThreadsPerChild
    50</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core (Windows,
    NetWare)<br />
     <strong>Compatibility:</strong> Available only with Apache 1.3
    and later with Windows 

    <p>This directive tells the server how many threads it should
    use. This is the maximum number of connections the server can
    handle at once; be sure and set this number high enough for
    your site if you get a lot of hits.</p>

    <p>This directive has no effect on Unix systems. Unix users
    should look at <a href="#startservers">StartServers</a> and <a
    href="#maxrequestsperchild">MaxRequestsPerChild</a>.</p>
    <hr />

    <h2><a id="threadstacksize"
    name="threadstacksize">ThreadStackSize</a></h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ThreadStackSize
    <em>number</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>ThreadStackSize
    65536</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core (NetWare)<br />
     <strong>Compatibility:</strong> Available only with Apache 1.3
    and later with NetWare 

    <p>This directive tells the server what stack size to use for
    each of the running threads. If you ever get a stack overflow
    you will need to bump this number to a higher setting.</p>

    <p>This directive has no effect on other systems.</p>
    <hr />

    <h2><a id="timeout" name="timeout">TimeOut directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> TimeOut
    <em>number</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>TimeOut
    300</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>The TimeOut 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>
    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. 
    <hr />

    <h2><a id="usecanonicalname"
    name="usecanonicalname">UseCanonicalName directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> UseCanonicalName
    on|off|dns<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>UseCanonicalName
    on</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host, directory<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> Options<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> UseCanonicalName
    is only available in Apache 1.3 and later 

    <p>In many situations Apache has to construct a
    <em>self-referential</em> URL. That is, a URL which refers back
    to the same server. With <code>UseCanonicalName on</code> (and
    in all versions prior to 1.3) Apache will use the <a
    href="#servername">ServerName</a> and <a href="#port">Port</a>
    directives to construct a 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). 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
    reauthenticate twice (once for <code>www</code> and once again
    for <code>www.domain.com</code>). But if
    <code>UseCanonicalName</code> is set off, 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>

    <p><strong>Warning:</strong> 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>

    <p><strong>See also:</strong> <a
    href="#servername">ServerName</a>, <a href="#port">Port</a></p>
    <hr />

    <h2><a id="user" name="user">User directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> User
    <em>unix-userid</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>User
    #-1</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> core 

    <p>The User directive sets the userid as which the server will
    answer requests. In order to use this directive, the standalone
    server must be run initially as root. <em>Unix-userid</em> is
    one of:</p>

    <dl>
      <dt>A username</dt>

      <dd>Refers to the given user by name.</dd>

      <dt># followed by a user number.</dt>

      <dd>Refers to a user by their number.</dd>
    </dl>
    The user should have no privileges which result in it being
    able to access files which are not intended to be visible to
    the outside world, and similarly, the user should not be able
    to execute code which is not meant for httpd requests. It is
    recommended that you set up a new user and group specifically
    for running the server. Some admins use user
    <code>nobody</code>, but this is not always possible or
    desirable. For example mod_proxy's cache, when enabled, must be
    accessible to this user (see the <a
    href="mod_proxy.html#cacheroot"><code>CacheRoot</code>
    directive</a>). 

    <p>Notes: If you start the server as a non-root user, it will
    fail to change to the lesser privileged user, and will instead
    continue to run as that original user. If you do start the
    server as root, then it is normal for the parent process to
    remain running as root.</p>

    <p>Special note: Use of this directive in &lt;VirtualHost&gt;
    requires a properly configured <a href="../suexec.html">suEXEC
    wrapper</a>. When used inside a &lt;VirtualHost&gt; in this
    manner, only the user that CGIs are run as is affected. Non-CGI
    requests are still processed with the user specified in the
    main User directive.</p>

    <p>SECURITY: Don't set User (or <a href="#group">Group</a>) to
    <code>root</code> unless you know exactly what you are doing,
    and what the dangers are.</p>
    <hr />

    <h2><a id="virtualhost" name="virtualhost">&lt;VirtualHost&gt;
    directive</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> &lt;VirtualHost
    <em>addr</em>[:<em>port</em>] [<em>addr</em>[:<em>port</em>]]
    ...&gt; ... &lt;/VirtualHost&gt; <br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Core.<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> Non-IP
    address-based Virtual Hosting only available in Apache 1.1 and
    later.<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> Multiple address
    support only available in Apache 1.2 and later. 

    <p>&lt;VirtualHost&gt; and &lt;/VirtualHost&gt; are used to
    enclose a group of directives which will apply only to a
    particular virtual host. Any directive which 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
    &lt;VirtualHost&gt; section. <em>Addr</em> can be</p>

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

      <li>A fully qualified domain name for the IP address of the
      virtual host.</li>
    </ul>
    Example: 

    <blockquote>
      <code>&lt;VirtualHost 10.1.2.3&gt;<br />
       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 />
       &lt;/VirtualHost&gt;</code>
    </blockquote>
    Each VirtualHost 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), or with kernel patches like <a
    href="../misc/vif-info.html">VIF</a> (for SunOS(TM) 4.1.x)). 

    <p>You can specify more than one IP address. This is useful if
    a machine responds to the same name on two different
    interfaces. For example, if you have a VirtualHost that is
    available to hosts on an internal (intranet) as well as
    external (internet) network. Example:</p>

    <blockquote>
      <code>&lt;VirtualHost 192.168.1.2 204.255.176.199&gt;<br />
       DocumentRoot /www/docs/host.foo.com<br />
       ServerName host.foo.com<br />
       ServerAlias host<br />
       &lt;/VirtualHost&gt;</code>
    </blockquote>
    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 _default_ virtual host the "main" server config,
    consisting of all those definitions outside any VirtualHost
    section, is used when no match occurs. 

    <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><a href="#port">Port</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><strong>SECURITY</strong>: 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 logfiles are stored is writable by anyone other
    than the user that starts the server.</p>

    <p><strong>NOTE</strong>: The use of &lt;VirtualHost&gt; does
    <strong>not</strong> affect what addresses Apache listens on.
    You may need to ensure that Apache is listening on the correct
    addresses using either <a href="#bindaddress">BindAddress</a>
    or <a href="#listen">Listen</a>.</p>

    <p><strong>See also:</strong> <a href="../vhosts/">Apache
    Virtual Host documentation</a><br />
     <strong>See also:</strong> <a
    href="../dns-caveats.html">Warnings about DNS and
    Apache</a><br />
     <strong>See also:</strong> <a href="../bind.html">Setting
    which addresses and ports Apache uses</a><br />
     <strong>See also</strong>: <a href="../sections.html">How
    Directory, Location and Files sections work</a> for an
    explanation of how these different sections are combined when a
    request is received</p>
        <hr />

    <h3 align="CENTER">Apache HTTP Server Version 1.3</h3>
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