[BlueOnyx:01514] Setting up sendmail to only accept mail from one external sendmail server

[Steve Davis]

I had a thought.

I have a Barracuda Spam & Virus server and a problematic BO mail server.

All of the domains that are on the BO server have a single MX record  
that points to the Barracuda. The Barracuda, scans, verifies good and  
forward mail to the BO server.

Spammers are attacking the BO directly.  I had 38,000 in the queue  
over a 6 hour period.

Could I setup the BO server to only accept smtp or smtps mail from the  
Barracuda.

I would need to keep the outgoing smtp connections open globally.  
Meaning the BO would need to establish its own connections to external  
mail server to deliver mail.

Users on this box generally do not POP and then send mail.  This would  
be another issue, that could be solved by requiring smtps or pop  
before relay.

Any ideas?

Steve