I'm getting a lot of viruses thru POP. How can I stop all attachments from going to my server?

Thanks in advances.

Sendmail has some good examples on their site explaining how to do this:

http://www.sendmail.org/~ca/email/chk-89.html

But Sendmail does not filter on content, only header information. So it cannot may not detect all vcariants of a virus/worm. If you want to block mail based on the type of attachment, you will need a third-party tool like MIMEDefang:

http://www.roaringpenguin.com/mimedefang/