Also on non RHEL Apache setups:
Code:
<VirtualHost>
...
Order deny,allow
Deny from all
Allow from 127.0.0.0/255.0.0.0 ::1/128
Allow from .example.com
...
</VirtualHost>
This will allow connections to the vhost from the domain .example.com (you could also use an IP range) and from localhost.