Pre February 2004

In the scenario above mail arrived at the DCU mail server via two routes

• directly from external sources
• through one of our external mx backups

February 2004 - June 2005

In the scenario above we added a number of new layers to mail processing

1. Mail Gateway
   We have put in place 2 mail gateways which process all mail destined for the DCU mail server. This allows us to weed out spam before it gets to the mail server.
2. MX Backups
   We moved away from dependency on MX Backups.
3. Postfix
   Our postfix config is based on Jim Seymour's anti-UCE cheat sheet.
4. Amavisd-New
   This is a high performance interface between the MTA (postfix) and virus/spam scanning.
5. Anti Virus
   Reject any mails containing a virus (using ClamAV).
6. SpamAssassin
   This program catches mail which it suspects to be spam.