This article outlines how to setup virus scanning using AMaViS (A Mail Virus Scanner), ClamAV, and Postfix. The actions describe below are particular to a FreeBSD system and are applicable to other operating systems by altering the path to the configuration files, and adjusting for other OS-specific issues.
What? Virus scanning on non-windows? Well, yes. My mail server happens to be running FreeBSD. It also happens to have many clients which are running Windows. Let's just stop the viruses before they get past my mail servers. Thank you. :)
This article is written as a reminder to me for the next time I configure virus scanning with amavisd. It is very high level.
A great article on how to implement a secure anti-virus email gateway. Better to block the virus before it gets to the user's PC, thus saving bandwidth and reducing the reliance on the user to do the right thing.
The majority of email-borne viruses have required some form of user intervention, such as clicking on the attachment. If you value your bandwidth and mail server resources, it's always a good idea to filter as much junk as you can before it reaches the end-user.