That's what Barracuda (http://www.barracudanetworks.com/) does with their "spam firewall." It can't be done solely with SA, but you could do something with your MTA of choice along with SA. I haven't built one of these myself, and Barracuda is understandably mum about how theirs works, but I think it would work sort of like this:
1. "Spam firewall" (SF hereafter) listens on your published MX IP. 2. MTA passes mail through SA, performs necessary tests, adds appropriate headers. MTA then either bounces mail, drops it on the floor (definitely not the right thing to do, but it's an option), or passes it... 3. MTA relays mail to real MX machine. ----- Original Message ----- From: "Ronald I. Nutter" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, June 22, 2004 10:30 Subject: Putting Spam Assasin between the internet and my mail server I am looking to implement Spamassasin. I have probably overlooked something but cant find a way that I can have it sit between the Internet and my mail server. I am using Exchange 2000 and converting from it to something else wont happen for a while. Is there a way to have it function as a smtp proxy for lack of a better word ? -------------------------------------------------------------------- Ron Nutter [EMAIL PROTECTED] Network Manager Information Technology Services Georgetown College Georgetown, KY --------------------------------------------------------------------
