<html><head><META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><!--
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      --><title>mod_vhost_alias - Apache HTTP Server</title><link href="../style/manual.css" type="text/css" rel="stylesheet"></head><body><blockquote><div align="center"><img src="../images/sub.gif" alt="[APACHE DOCUMENTATION]"><h3>Apache HTTP Server Version 2.0</h3></div><h1 align="center">Apache Module mod_vhost_alias</h1><table cellspacing="1" cellpadding="0" bgcolor="#cccccc"><tr><td><table bgcolor="#ffffff"><tr><td nowrap="nowrap" valign="top"><span class="help">Description:
                      </span></td><td>Provides for dynamically configured mass virtual
hosting</td></tr><tr><td nowrap="nowrap"><a href="module-dict.html#Status" class="help">Status:
                      </a></td><td>Extension</td></tr><tr><td nowrap="nowrap"><a href="module-dict.html#ModuleIdentifier" class="help">Module&nbsp;Identifier:
                        </a></td><td>vhost_alias_module</td></tr></table></td></tr></table><h2>Summary</h2>

    <p>This module creates dynamically configured virtual hosts, by
    allowing the IP address and/or the <code>Host:</code> header of
    the HTTP request to be used as part of the pathname to
    determine what files to serve. This allows for easy use of a
    huge number of virtual hosts with similar configurations.</p>


<h2>Directives</h2><ul><li><a href="#virtualdocumentroot">VirtualDocumentRoot</a></li><li><a href="#virtualdocumentrootip">VirtualDocumentRootIP</a></li><li><a href="#virtualscriptalias">VirtualScriptAlias</a></li><li><a href="#virtualscriptaliasip">VirtualScriptAliasIP</a></li></ul><p><strong>See also </strong></p><ul><li><a href="../mod/core.html#usecanonicalname" class="directive"><code class="directive">UseCanonicalName</code></a>.</li><li><a href="../vhosts/mass.html">Dynamically configured mass 
virtual hosting</a></li></ul><h2>Directory Name Interpolation</h2>
    

    <p>All the directives in this module interpolate a string into
    a pathname. The interpolated string (henceforth called the
    "name") may be either the server name (see the <a href="core.html#usecanonicalname"><code>UseCanonicalName</code></a>
    directive for details on how this is determined) or the IP
    address of the virtual host on the server in dotted-quad
    format. The interpolation is controlled by specifiers inspired
    by <code>printf</code> which have a number of formats:</p>

<table>

<tr><td><code>%%</code></td>
<td>insert a <code>%</code></td></tr>

<tr><td><code>%p</code></td>
<td>insert the port number of the virtual host</td></tr>

<tr><td><code>%N.M</code></td>
<td>insert (part of) the name</td></tr>
     
</table>

    <p><code>N</code> and <code>M</code> are used to specify
    substrings of the name. <code>N</code> selects from the
    dot-separated components of the name, and <code>M</code>
    selects characters within whatever <code>N</code> has selected.
    <code>M</code> is optional and defaults to zero if it isn't
    present; the dot must be present if and only if <code>M</code>
    is present. The interpretation is as follows:</p>

    <table>
      <tr><td><code>0</code></td>
      <td>the whole name</td></tr>

      <tr><td><code>1</code></td>
      <td>the first part</td></tr>

      <tr><td><code>2</code></td>
      <td>the second part</td></tr>

      <tr><td><code>-1</code></td>
      <td>the last part</td></tr>

      <tr><td><code>-2</code></td>
      <td>the penultimate part</td></tr>

      <tr><td><code>2+</code></td>
      <td>the second and all subsequent parts</td></tr>

      <tr><td><code>-2+</code></td>
      <td>the penultimate and all preceding parts</td></tr>

      <tr><td><code>1+</code> and <code>-1+</code></td>
      <td>the same as <code>0</code></td></tr>
    </table>

    <p>If <code>N</code> or <code>M</code> is greater than the number
    of parts available a single underscore is interpolated. </p>

<h2>Examples</h2>
    

    <p>For simple name-based virtual hosts you might use the
    following directives in your server configuration file:</p>

<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code>
    UseCanonicalName    Off<br>
    VirtualDocumentRoot /usr/local/apache/vhosts/%0
</code></td></tr></table></blockquote>

    <p>A request for
    <code>http://www.example.com/directory/file.html</code> will be
    satisfied by the file
    <code>/usr/local/apache/vhosts/www.example.com/directory/file.html</code>.
    </p> 

    <p>For a very large number of virtual hosts it is a good idea
    to arrange the files to reduce the size of the
    <code>vhosts</code> directory. To do this you might use the
    following in your configuration file:</p>

<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code>
    UseCanonicalName    Off<br>
    VirtualDocumentRoot /usr/local/apache/vhosts/%3+/%2.1/%2.2/%2.3/%2
</code></td></tr></table></blockquote>

    <p>A request for
    <code>http://www.example.isp.com/directory/file.html</code>
    will be satisfied by the file
    <code>/usr/local/apache/vhosts/isp.com/e/x/a/example/directory/file.html</code>.</p>

    <p>A more even spread of files can be achieved by hashing from the
    end of the name, for example: </p>

<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code>
    VirtualDocumentRoot /usr/local/apache/vhosts/%3+/%2.-1/%2.-2/%2.-3/%2
</code></td></tr></table></blockquote>

    <p>The example request would come from
    <code>/usr/local/apache/vhosts/isp.com/e/l/p/example/directory/file.html</code>.</p>

    <p>Alternatively you might use: </p>

<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code>
    VirtualDocumentRoot /usr/local/apache/vhosts/%3+/%2.1/%2.2/%2.3/%2.4+
</code></td></tr></table></blockquote>

    <p>The example request would come from
    <code>/usr/local/apache/vhosts/isp.com/e/x/a/mple/directory/file.html</code>.</p>

    <p>For IP-based virtual hosting you might use the following in
    your configuration file:</p>

<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code>
    UseCanonicalName DNS<br>
    VirtualDocumentRootIP   /usr/local/apache/vhosts/%1/%2/%3/%4/docs<br>
    VirtualScriptAliasIP    /usr/local/apache/vhosts/%1/%2/%3/%4/cgi-bin
</code></td></tr></table></blockquote>

    <p>A request for
    <code>http://www.example.isp.com/directory/file.html</code>
    would be satisfied by the file
    <code>/usr/local/apache/vhosts/10/20/30/40/docs/directory/file.html</code>
    if the IP address of <code>www.example.com</code> were
    10.20.30.40. A request for
    <code>http://www.example.isp.com/cgi-bin/script.pl</code> would
    be satisfied by executing the program
    <code>/usr/local/apache/vhosts/10/20/30/40/cgi-bin/script.pl</code>.</p>

    <p>If you want to include the <code>.</code> character in a
    <code>VirtualDocumentRoot</code> directive, but it clashes with
    a <code>%</code> directive, you can work around the problem in
    the following way:</p>

<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code>
    VirtualDocumentRoot /usr/local/apache/vhosts/%2.0.%3.0
</code></td></tr></table></blockquote>

    <p>A request for
    <code>http://www.example.isp.com/directory/file.html</code>
    will be satisfied by the file
    <code>/usr/local/apache/vhosts/example.isp/directory/file.html</code>.</p>
     
    <p>The <a href="../mod/mod_log_config.html#logformat" class="directive"><code class="directive">LogFormat</code></a>
    directives <code>%V</code> and <code>%A</code> are useful
    in conjunction with this module.</p>
<hr><h2><a name="VirtualDocumentRoot">VirtualDocumentRoot</a> <a name="virtualdocumentroot">Directive</a></h2><table cellpadding="1" cellspacing="0" border="0" bgcolor="#cccccc"><tr><td><table bgcolor="#ffffff"><tr><td nowrap="nowrap"><strong>Description: 
                  </strong></td><td>Dynamically configure the location of the document root
for a given virtual host</td></tr><tr><td nowrap="nowrap"><a href="directive-dict.html#Syntax" class="help">Syntax:
                  </a></td><td>VirtualDocumentRoot <em>interpolated-directory</em></td></tr><tr><td nowrap="nowrap"><a href="directive-dict.html#Default" class="help">Default: 
                    </a></td><td><code>none</code></td></tr><tr><td nowrap="nowrap"><a href="directive-dict.html#Context" class="help">Context:
                  </a></td><td>server config, virtual host</td></tr><tr><td nowrap="nowrap"><a href="directive-dict.html#Status" class="help">Status:
                  </a></td><td>Extension</td></tr><tr><td nowrap="nowrap"><a href="directive-dict.html#Module" class="help">Module:
                  </a></td><td>mod_vhost_alias</td></tr></table></td></tr></table>

    <p>The <code>VirtualDocumentRoot</code> directive allows you to
    determine where Apache will find your documents based on the
    value of the server name. The result of expanding
    <em>interpolated-directory</em> is used as the root of the
    document tree in a similar manner to the <a href="../mod/core.html#documentroot" class="directive"><code class="directive">DocumentRoot</code></a> directive's argument. 
    If <em>interpolated-directory</em> is <code>none</code> then
    <code>VirtaulDocumentRoot</code> is turned off. This directive 
    cannot be used in the same context as
    <code class="directive">VirtualDocumentRootIP</code>.</p>

<hr><h2><a name="VirtualDocumentRootIP">VirtualDocumentRootIP</a> <a name="virtualdocumentrootip">Directive</a></h2><table cellpadding="1" cellspacing="0" border="0" bgcolor="#cccccc"><tr><td><table bgcolor="#ffffff"><tr><td nowrap="nowrap"><strong>Description: 
                  </strong></td><td>Dynamically configure the location of the document root
for a given virtual host</td></tr><tr><td nowrap="nowrap"><a href="directive-dict.html#Syntax" class="help">Syntax:
                  </a></td><td>VirtualDocumentRootIP <em>interpolated-directory</em></td></tr><tr><td nowrap="nowrap"><a href="directive-dict.html#Default" class="help">Default: 
                    </a></td><td><code>none</code></td></tr><tr><td nowrap="nowrap"><a href="directive-dict.html#Context" class="help">Context:
                  </a></td><td>server config, virtual host</td></tr><tr><td nowrap="nowrap"><a href="directive-dict.html#Status" class="help">Status:
                  </a></td><td>Extension</td></tr><tr><td nowrap="nowrap"><a href="directive-dict.html#Module" class="help">Module:
                  </a></td><td>mod_vhost_alias</td></tr></table></td></tr></table>

<p>The <code>VirtualDocumentRootIP</code> directive is like the
    <code class="directive">VirtualDocumentRoot</code>
    directive, except that it uses the IP address of the server end
    of the connection instead of the server name.</p>
<hr><h2><a name="VirtualScriptAlias">VirtualScriptAlias</a> <a name="virtualscriptalias">Directive</a></h2><table cellpadding="1" cellspacing="0" border="0" bgcolor="#cccccc"><tr><td><table bgcolor="#ffffff"><tr><td nowrap="nowrap"><strong>Description: 
                  </strong></td><td>Dynamically configure the location of the CGI directory for
a given virtual host</td></tr><tr><td nowrap="nowrap"><a href="directive-dict.html#Syntax" class="help">Syntax:
                  </a></td><td>VirtualScriptAlias <em>interpolated-directory</em></td></tr><tr><td nowrap="nowrap"><a href="directive-dict.html#Default" class="help">Default: 
                    </a></td><td><code>none</code></td></tr><tr><td nowrap="nowrap"><a href="directive-dict.html#Context" class="help">Context:
                  </a></td><td>server config, virtual host</td></tr><tr><td nowrap="nowrap"><a href="directive-dict.html#Status" class="help">Status:
                  </a></td><td>Extension</td></tr><tr><td nowrap="nowrap"><a href="directive-dict.html#Module" class="help">Module:
                  </a></td><td>mod_vhost_alias</td></tr></table></td></tr></table>

    <p>The <code>VirtualScriptAlias</code> directive allows you to
    determine where Apache will find CGI scripts in a similar
    manner to <code class="directive">VirtualDocumentRoot</code>
    does for other documents. It matches requests for URIs starting
    <code>/cgi-bin/</code>, much like <a href="../mod/mod_alias.html#scriptalias" class="directive"><code class="directive">ScriptAlias</code></a>
    <code>/cgi-bin/</code> would.</p>

<hr><h2><a name="VirtualScriptAliasIP">VirtualScriptAliasIP</a> <a name="virtualscriptaliasip">Directive</a></h2><table cellpadding="1" cellspacing="0" border="0" bgcolor="#cccccc"><tr><td><table bgcolor="#ffffff"><tr><td nowrap="nowrap"><strong>Description: 
                  </strong></td><td>Dynamically configure the location of the cgi directory for
a given virtual host</td></tr><tr><td nowrap="nowrap"><a href="directive-dict.html#Syntax" class="help">Syntax:
                  </a></td><td>VirtualScriptAliasIP <em>interpolated-directory</em></td></tr><tr><td nowrap="nowrap"><a href="directive-dict.html#Default" class="help">Default: 
                    </a></td><td><code>none</code></td></tr><tr><td nowrap="nowrap"><a href="directive-dict.html#Context" class="help">Context:
                  </a></td><td>server config, virtual host</td></tr><tr><td nowrap="nowrap"><a href="directive-dict.html#Status" class="help">Status:
                  </a></td><td>Extension</td></tr><tr><td nowrap="nowrap"><a href="directive-dict.html#Module" class="help">Module:
                  </a></td><td>mod_vhost_alias</td></tr></table></td></tr></table>

    <p>The <code>VirtualScriptAliasIP</code> directive is like the
    <a href="#virtualscriptalias"><code>VirtualScriptAlias</code></a>
    directive, except that it uses the IP address of the server end
    of the connection instead of the server name.</p>

    <hr></blockquote><h3 align="center">Apache HTTP Server Version 2.0</h3><a href="./"><img src="../images/index.gif" alt="Index"></a><a href="../"><img src="../images/home.gif" alt="Home"></a></body></html>