Using wildcards in Apache server aliases
Apache allows you to create hundreds of virtual host containers. Each container is required to have a ServerName directive, which contains the domain name associated with the virtual host. In addition to a server name, one ore more aliases can be associated with the virtual host with the ServerAlias directive. Aliases can contain a domain, or a regex that allows you to match based on some specific criteria. This is super useful, and allows you to do things like this:
NameVirtualHost 192.168.1.18:8080
<VirtualHost 192.168.1.18:8080>
ServerName foo.com
ServerAlias *.foo.com
</VirtualHost>
<VirtualHost 192.168.1.18:8080>
ServerName bar.com
ServerAlias *.bar.com
</VirtualHost>
This opens a whole slew of cool and interesting possibilities for virtual hosting. Niiiiice!
moo on January 8th, 2007
Another great Apache virtual hosting feature is Dynamically Configured Mass Virtual Hosting.
http://httpd.apache.org/docs/2.0/vhosts/mass.html
It allows you to keep your apache config small and simple and add vhosts without changing the config or even restarting/reloading apache. I used to have this in place on a webserver I ran and it was excellent.