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Spam War: The Complete Documentation

• This category contains 3 Papers
• The last paper was added on 2007-03-26 (YYYY-MM-DD)

Filtering E-Mail with Postfix and Procmail, Part One

Published on 2002-06-17, by Brian Hatch, ©SecurityFocus.

Most folks dislike spam in their e-mail. Spam takes up our network, disk, and cpu resources. It requires that we weed through unwanted messages to find the ones that we requested. (I'm not going to try to convince you that spam is not good, you can check out some of the anti-spam resources listed in the relevant links section below, if you're interested.)

Filtering E-Mail with Postfix and Procmail, Part Two

Published on 2002-06-26, by Brian Hatch, ©SecurityFocus.

This article is the second of three articles that will help systems administrators configure SMTP daemons and local mail delivery agents to filter out unwanted e-mails before they arrive in the end-users' in-box. In the first installment, we offered a brief overview of Postfix, and began a discussion of rejecting spam with Postfix by blocking e-mail based on the SMTP client, blocking machines with no reverse DNS, SMTP client map restrictions, DNS blackhole lists, bundling Postfix restriction options, and blocking spam based on SMTP Compliance. In this part, we will look at sender/recipient restrictions, restriction ordering, and map file naming conventions before moving on to Procmail in the final article.

Fine-tuning SpamAssassin

Published on 2004, by Neil Youngman, ©Neil Youngman.

SpamAssassin, as most of our readers will know, is a popular spam classifier on Linux. This article assumes that you already have SpamAssassin installed and working. If you are interested in running SpamAssassin, but do not yet have it set up, there is a useful introduction at http://linux.org.mt/article/killspam. When I set up SpamAssassin in Mandrake 9.2, it came very close to picking up 100% of my spam. Over time, however, many of the spammers have figured out how to fine tune their spam and bypass the default ruleset. I find the default setup still picks up at least half the spam, maybe two thirds on a good day, but too much leaks through. If the spammers are tuning their messages, I guess the only thing to do is to tune my scoring. There are at least 8 possible ways of improving SpamAssassin's hit rate.