Virtual Host examples for common setups

Using _default_ vhosts

• Setup 1: Catching every request to any unspecified IP address and port, i.e., an address/port combination that is not used for any other virtual host.

  Server configuration:

      ...
      <VirtualHost _default_:*>
      DocumentRoot /www/default
      ...
      </VirtualHost>
     
  

  Using such a default vhost with a wildcard port effectively prevents any request going to the main server.
  A default vhost never serves a request that was sent to an address/port that is used for name-based vhosts. If the request contained an unknown or no Host: header it is always served from the primary name-based vhost (the vhost for that address/port appearing first in the configuration file).
  You can use AliasMatch or RewriteRule to rewrite any request to a single information page (or script).

• Setup 2: Same as setup 1, but the server listens on several ports and we want to use a second _default_ vhost for port 80.

  Server configuration:

      ...
      <VirtualHost _default_:80>
      DocumentRoot /www/default80
      ...
      </VirtualHost>
      
      <VirtualHost _default_:*>
      DocumentRoot /www/default
      ...
      </VirtualHost>    
     
  

  The default vhost for port 80 (which must appear before any default vhost with a wildcard port) catches all requests that were sent to an unspecified IP address. The main server is never used to serve a request.

• Setup 3: We want to have a default vhost for port 80, but no other default vhosts.

  Server configuration:

      ...
      <VirtualHost _default_:80>
      DocumentRoot /www/default
      ...
      </VirtualHost>
     
  

  A request to an unspecified address on port 80 is served from the default vhost any other request to an unspecified address and port is served from the main server.

Migrating a name-based vhost to an IP-based vhost

• Setup: The name-based vhost with the hostname www.otherdomain.tld (from our name-based example, setup 2) should get its own IP address. To avoid problems with name servers or proxies who cached the old IP address for the name-based vhost we want to provide both variants during a migration phase.
  The solution is easy, because we can simply add the new IP address (111.22.33.66) to the VirtualHost directive.

  Server configuration:

      ...
      Port 80
      ServerName www.domain.tld
      DocumentRoot /www/domain
  
      NameVirtualHost 111.22.33.55
  
      <VirtualHost 111.22.33.55 111.22.33.66>
      DocumentRoot /www/otherdomain
      ServerName www.otherdomain.tld
      ...
      </VirtualHost>
     
      <VirtualHost 111.22.33.55>
      DocumentRoot /www/subdomain
      ServerName www.sub.domain.tld
      ServerAlias *.sub.domain.tld
      ...
      </VirtualHost>
     
  

  The vhost can now be accessed through the new address (as an IP-based vhost) and through the old address (as a name-based vhost).

Using the ServerPath directive

• Setup: We have a server with two name-based vhosts. In order to match the correct virtual host a client must send the correct Host: header. Old HTTP/1.0 clients do not send such a header and Apache has no clue what vhost the client tried to reach (and serves the request from the primary vhost). To provide as much backward compatibility as possible we create a primary vhost which returns a single page containing links with an URL prefix to the name-based virtual hosts.

  Server configuration:

      ...
      NameVirtualHost 111.22.33.44
  
      <VirtualHost 111.22.33.44>
      # primary vhost
      DocumentRoot /www/subdomain
      RewriteEngine On
      RewriteRule ^/.* /www/subdomain/index.html
      ...
      </VirtualHost>
  
      <VirtualHost 111.22.33.44>
      DocumentRoot /www/subdomain/sub1
      ServerName www.sub1.domain.tld
      ServerPath /sub1/
      RewriteEngine On
      RewriteRule ^(/sub1/.*) /www/subdomain$1 
      ...
      </VirtualHost>
  
      <VirtualHost 111.22.33.44>
      DocumentRoot /www/subdomain/sub2
      ServerName www.sub2.domain.tld
      ServerPath /sub2/
      RewriteEngine On
      RewriteRule ^(/sub2/.*) /www/subdomain$1 
      ...
      </VirtualHost>
     
  

  Due to the ServerPath directive a request to the URL http://www.sub1.domain.tld/sub1/ is always served from the sub1-vhost.
  A request to the URL http://www.sub1.domain.tld/ is only served from the sub1-vhost if the client sent a correct Host: header. If no Host: header is sent the client gets the information page from the primary host.
  Please note that there is one oddity: A request to http://www.sub2.domain.tld/sub1/ is also served from the sub1-vhost if the client sent no Host: header.
  The RewriteRule directives are used to make sure that a client which sent a correct Host: header can use both URL variants, i.e., with or without URL prefix.

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Disclaimer: This documentation is provided only for the benefits of our hosting customers.
For authoritative source of the documentation, please refer to http://httpd.apache.org/docs/