A technology called BATV was proposed but never got widespread adoption (so far). There is at least one open source filter that implements it that you could try, though it is unmaintained. It has a few side effects, so read up on it before throwing the switch.
From: owner-postfix-us...@postfix.org [mailto:owner-postfix-us...@postfix.org] On Behalf Of Simon Sent: Tuesday, February 01, 2011 3:39 PM To: postfix users list Subject: Spam Backscatter We are using postfix with debian lenny... We are receiving what appears to be backscatter from spam that is using a valid address in the Return Path. I have included an example of the header info from one of the spam messages below. The "From" and "To" addresses just seem to be random and are not related to us in any way. Does anyone know to block this sort of backscatter? Original message headers: Return-Path: <soa@*<mailto:s...@newmedia.net.nz>*[ourdomain.actual.domain]**> Received: from 195-191-72-102.optolan.net.ua<http://195-191-72-102.optolan.net.ua> (unknown [195.191.72.102]) by smtp-0.counselschambers.com.au<http://smtp-0.counselschambers.com.au> (Postfix) with ESMTP id 1D400396B7E for <so...@tenthfloor.org<mailto:so...@tenthfloor.org>>; Wed, 2 Feb 2011 08:28:43 +1100 (EST) From: no-reply...@job.com<mailto:no-reply...@job.com> To: <so...@tenthfloor.org<mailto:so...@tenthfloor.org>> Subject: Position opening in your area MIME-Version: 1.0 Importance: High Content-Type: text/html Message-ID: <20110201212844.1d400396...@smtp-0.counselschambers.com.au<mailto:20110201212844.1d400396...@smtp-0.counselschambers.com.au>> Date: Wed, 2 Feb 2011 08:28:43 +1100 Thanks Simon
