I have a script that takes the local domains list from the server
and resolves each domain.
The list gets ordered by IP address and any that are resolving to other IP's go on the lsit to be deleted.
Just watch out for subdomains when doing that!
We had our main site hosted on one of our servers and set up another account on a subdomain elsewhere for a special project. The host would only setup service on example.com, which was fine, we just weren't going to use it - instead we went in and created subdom.example.com, pointed our dns at their server, and everything worked fine - until their reaper script decided we weren't using their server.
Moral of the story - have your script check for subdomains in all your accounts and only delete if NONE of them (example.com, www.example.com, and sub.example.com) is pointing at your servers.
-Russ
