Procmail is a mail delivery agent that is used by a number of applications in this book to filter messages according to various attributes. The utility comes with most distributions of Linux, and it is easy to install and configure for use with Sendmail, Postfix, and qmail. procmail can be called directly by the mail delivery agent for Postfix and Sendmail or indirectly by .forward files on a per-user basis. Under qmail, procmail must be invoked via .qmail files because qmail has no direct integration with Procmail (besides per-user .qmail files).

Procmail recipes are terse in nature, which also makes them somewhat cryptic and difficult to grasp. Recipes can live in /etc/procmailrc for all users or .procmailrc in each user’s directory. ...

Get Slamming Spam: A Guide for System Administrators now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.