I am in the process of replacing Eskimo’s mail servers. I’ve got one new server up and running for inbound, working on the 2nd, and then the client mail server will be next.
It’s a bit messy and that is pretty much unavoidable. The new servers are i7-2600 based, running CentOS 6.4, and completely different software. They are using Postfix instead of Sendmail, and are using clam-av and spam-assassin. They use Procmail as the delivery agent, hence it will no longer be necessary to have a .forward to a procmail_wrapper; everything will automatically direct through Procmail for delivery.
When everything is done, you will be able to train spam-assassin by mailing examples of good mail and bad mail to addresses for that purpose or by pressing a spam button in webmail. You will be able to set individually the threshold at which mail is considered spam and specify the handling of it via procmail rules.
Viruses are rejected outright but a mail is sent back to the sender telling them there mail was rejected and which virus it contained so that they can take the necessary actions to disinfect their computer.
I urge your patience while this process takes place; in the end it will be worth it, far less spam, less false positives, and more control over your mail, and the client server will have proper certificates so picky clients will work properly. But getting there is somewhat messy. It will probably take 2-3 weeks to complete this transition.
Because the software is completely new, this is a learning curve for me as well. There are many components and unanticipated interactions can occur.