VirtualHost Examples: Using _default_ vhosts

This document attempts to answer the commonly-asked questions about setting up virtual hosts.

These scenarios are those involving multiple web sites running on a single server, via name-based or IP-based virtual hosts.

_default_ vhosts for all ports

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).
_default_ vhosts for different ports

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.
_default_ vhosts for one port

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.