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Backup Email Servers

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kelsky View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote kelsky Quote  Post ReplyReply Direct Link To This Post Topic: Backup Email Servers
    Posted: 17 August 2004 at 2:30pm

I use a service that will become my backup email server should mine go off-line.  It will hold the email and then forward it onto mine when mine is back on-line.  The problem is that spamfilter sees this backup email server as the host IP for the email and it will pass everytime because it is not on a blacklist.  (lets hope it never is also).  Anyway, the other hole this creates it that spammers could intentionally go to my secondary MX records and email directly to it knowing it will validate the IP.  Thoughts?

Here is an example:  Spamfilter should have processed against not my backup email server 63.219.###.###


08/17/04 13:04:38:015 -- (1508) Resolving 63.219.###.### -
08/17/04 13:04:38:156 -- (1508) - SPF analysis done: - none
08/17/04 13:04:38:156 -- (1508) Mail from:
08/17/04 13:04:43:406 -- (1508) - MAPS search done...
08/17/04 13:04:43:406 -- (1508) RCPT TO: accepted
08/17/04 13:04:43:718 -- (1508) EMail from to was queued. Size: 3 KB, 3072 bytes
08/17/04 13:04:43:734 -- (700) Sending email from to ###@#####.com08/17/04 13:04:43:812 -- (1508) Disconnect
08/17/04 13:04:44:609 -- (700) EMail from to was forwarded to


Return-Path: <>
Delivered-To: Return-Path: <>
Received: (qmail 4329 invoked by uid 507); 17 Aug 2004 14:00:10 -0400
Received: from (HELO dell2350) (69.27.###.###)
  by with SMTP; 17 Aug 2004 14:00:10 -0400
Received: from 63.219.###.### by  (LogSat Software SMTP Server) Tue, 17 Aug 2004 13:04:43 -0500
Received: (qmail 27359 invoked from network); 17 Aug 2004 15:25:12 -0000
Received: from (
  by with SMTP; 17 Aug 2004 15:25:12 -0000
Message-Id: <830U35906FD7O367I9GMLWP0N@OEV003ZLU94HZWE5Z20U092Q5>
From: Satellite Television USA <>
Subject: DIRECTV, Tivo + DVD player - no charge
Date: Tue, 17 Aug 2004 10:18:17 -0400
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/html; charset = "iso-8859-1"
X-Server: LogSat Software SMTP Server

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Post Options Post Options   Thanks (0) Thanks(0)   Quote LogSat Quote  Post ReplyReply Direct Link To This Post Posted: 17 August 2004 at 11:26pm


Spammers are known to send spam email to all servers for which an MX record exists. If you have a secondary MX record for your domain(s), it will receive spam. Your backup "service" should run an anti-spam application on their end so they can give you clean email.

When the backup server forwards you the email, as you've seen, SpamFilter will "see" the IP address of that backup server, not the original IP of the sender, so all of SpamFilter's IP-based filter will not work, and you will be left with the keyword and Bayesian filters only. There is not really a workaround for this, as normally users own both primary and secondary MX servers, and install SpamFilter as a gateway for both of them.

Roberto F.
LogSat Software

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Post Options Post Options   Thanks (0) Thanks(0)   Quote kspare Quote  Post ReplyReply Direct Link To This Post Posted: 18 August 2004 at 10:25am

Kelsky, fire me an email, I can probably help you out with your situation.

You can get me @



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