David - 2:45 pm on Sep 20, 2002 (gmt 0)
The reverse record should be all you need tying your IP back to your domain name. I don't know how it is done but I just had to have it done for a new IP / Domain.
For the paranoid (like me) SMTP VRFY should be disabled for security reasons. It opens a door that can be used to probe for user names and mail lists.