sendmail Milters: A Guide for Fighting Spam (Repost)

As a Mail Administrator You Need to Understand How to Successfully Monitor and Fight Spam.
Milters are among the most powerful antispamming tools available. Until now, there has been no clear and helpful resource for you to learn how to set up and use Milters. sendmail Milters: A Guide for Fighting Spam is the first in-depth guide to writing powerful Milters to block even the most clever spammers.