MailScanner with Spamassassin is what I would recommend.
From: ivan.hernandez () globalsis com ar
[mailto:ivan.hernandez () globalsis com ar] Sent: Tuesday, April 27,
2004 10:29 AM
To: security-basics () securityfocus com
Subject: Filtering SPAM with Linux
Hello. I have a box with linux that is acting as NAT and Firewall (also
cache with squid and reverse proxy with pound).
I have an internal MS Exchange server that goes to internet via NAT,
dont have any chance of removing it, but i would like to filter the
traffic to remove spam.
My net looks something like this:
INTERNET <---> x.x.x.x LINUX BOX 10.1.20.100 <---> 10.1.20.1 MS Exchange
What can i use in the linux box? I have found things like MessageWall
so, but i need better recomendations from people that already doed it.