We use zimbra OSS on SLES10 SP1. Zimbra has spamassassin built-in. At
the present time, my mailbox is filled with backscatter; getting
around 10 a minute since 4:30 today. I have postfix backscatter rules
in postfix of zimbra, http://www.postfix.org/BACKSCATTER_README.html#real
but still getting pounded. Here is the header from on such mail:

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:

SMTP error from remote mail server after RCPT TO:
host relay1.tm.odessa.ua []: 511 sorry, no mailbox
here by that name (#5.1.1 - chkuser)

------ This is a copy of the message, including all the headers. ------

Received: from chello089074205165.chello.pl ([])
by wifi-router.tm.odessa.ua with esmtp (Exim 4.69 (FreeBSD))
(envelope-from )
id 1KvJP6-000Eho-L0
for marykiev@tm.odessa.ua; Thu, 30 Oct 2008 00:20:42 +0200
Message-ID: <000701c93a14$03bd0ac0$c9377bbf@weuwrbe>
From: =?koi8-r?B?4c3X0s/Tycog4czT2c7Cwco=?=
Subject: =?koi8-r?B?5dfSz9DFytPLwdEgzsXExczRIMvB3sXT1NfB?=
Date: Wed, 29 Oct 2008 20:30:54 +0000
MIME-Version: 1.0
Content-Type: multipart/alternative;
X-Priority: 3
X-MSMail-Priority: Normal
X-Mailer: Microsoft Outlook Express 6.00.2720.3000
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2727.1300

This is a multi-part message in MIME format.

Content-Type: text/plain;
Content-Transfer-Encoding: quoted-printable

Can someone please help me stop this? A while back, there was a thread
that pointed to a website, backscatter.org or something like that,
that we used that since the upgrade did a wonderful job. Anyone
remember that web site?