See README_FILES/SMTPD_POLICY_README For an example greylisting filter using perl in postfix.
-----Original Message----- From: Andrew P. Kaplan [mailto:[EMAIL PROTECTED] Sent: Friday, March 05, 2004 9:16 AM To: IMGate Subject: [IMGate] greylisting - something to take you mind of Bagel http://projects.puremagic.com/greylisting/ It's Friday so here's a break from bagel The Greylisting Method High Level Overview Greylisting got it's name because it is kind of a cross between black- and white-listing, with mostly automatic maintenance. A key element of the Greylisting method is this automatic maintenance. The Greylisting method is very simple. It only looks at three pieces of information (which we will refer to as a "triplet" from now on) about any particular mail delivery attempt: 1.. The IP address of the host attempting the delivery 2.. The envelope sender address 3.. The envelope recipient address >From this, we now have a unique triplet for identifying a mail "relationship". With this data, we simply follow a basic rule, which is: If we have never seen this triplet before, then refuse this delivery and any others that may come within a certain period of time with a temporary failure. Since SMTP is considered an unreliable transport, the possibility of temporary failures is built into the core spec (see RFC 821). As such, any well behaved message transfer agent (MTA) should attempt retries if given an appropriate temporary failure code for a delivery attempt (see below for discussion of issues concerning non-conforming MTA's). Andrew P. Kaplan www.cshore.com If you want to build a ship, don't drum up the men to gather wood, divide the work and give orders. Instead, teach them to yearn for the vast and endless sea. Antoine-Marie-Roger de Saint-Exupery
