Sendmail without DNS part Deux

I spent the past couple of days beating my head against the wall trying to make Sendmail 8.12.10 work with a mail gateway in a DNS-less environment. You may remember that I blogged back in January about how I got it working before.Sendmail 8.12.10 uses the Sendmail Message Submission Program (SMMSP) and it is pretty picky with resolving domain names before sending mail onto the Sendmail MTA.After I was completely out of ideas I finally broke down to call Red Hat Enterprise Support to see if their Sendmail Guru knew how to get this working. In less than 10 minutes I was talking to the Sendmail Guru and he said that it was basically impossible. He suggested a method that I had thought of, but didn’t think was a very good way of implementing it.The workaround is to setup dummy entries for the domains of the email Sendmail will be sending to. Since Sendmail is using a mail gateway for all of its mail, it doesn’t really matter what the domains resolve to for Sendmail, they just need to resolve to satisfy the SMMSP.The moral of this story is that I should of called support and got the answer a few days ago.