Here's my situation: server1: mail gateway, runs Spamassassin server2: multi-purpose server. hosts http, mail boxes, pop/imap, runs sendmail and Spamassassin. example.org: my domain. The MX record points to server1, A record points to server2
The problem with this setup of course, is that spammers tend to send directly to server2, bypassing server1 (the mail scanner/filter). My original idea was to either configure server2 to reject mail not arriving directly from server1 (either via iptables or sendmail.cf). The problem is that I have a dozen or so users who use SMTP AUTH to relay mail out through server2. Sometimes this mail will be relayed to 3rd party domains, other times it will be sent to fellow users on example.org. My thoughts at the moment are to write some Spamasssin rules for server2 which will penalize mail which doesn't arrive from server2 (or localhost) and wasn't sent by an authenticated user. Does this sound like a good way to proceed? Perhaps I'm missing a simpler way to do things? Thanks, Peter Smith
