I had this problem on a list of mine. I traced it down to a subscription where the address was invalid, and the mail server was part of a dns/mx forward loop. The address was almost certainly one of a spammer (or used by a spammer) who was trying to post to the list. What would happen is I would send out a message and my users would get up to 8 copies of it. I basically ended up cutting the list down to just a few people (saving the original list) that were in my company, then adding the users in reverse order and sending an email out until I got the duplicates. When I found the culprit and tried to tracert their site what I got was a loop, it would go to a certain point, then bounce back and forth between two servers - each referencing the other. I suspect that a similar thing was happening somehow in SMTP and in some bizarre way (I don't pretend to be an smtp expert) it was "amplifying" the outgoing email, resending it multiple times to everyone on the list. I killed this guy's address, added their domain to the kill list, and haven't had the problem since. If it happens again, I'll make note of the date of my last message, check my users that have subscribed since then (I always get a subscribe message), then add them to a test mailing list one at a time until it does the amplify thing. I also immediately kill users who's email addresses reject the subscription notice. The spammers certainly know how to use email lists to their own advantage and will attempt to do so every way they know how.
Lee Drake -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of R. Scott Perry Sent: Thursday, August 01, 2002 12:06 PM To: [EMAIL PROTECTED] Subject: RE: [IMail Forum] Duplicate Emails Problem >That was our first thought too... but actually this headers are from a >single email address of mine that was on the list to kinda to keep tabs >on what was happening... :-) Which of the 3 E-mail addresses was the single E-mail address of yours? [EMAIL PROTECTED], [EMAIL PROTECTED], or [EMAIL PROTECTED]? Which of those 3 addresses was on the list? The headers show that qmail received 2 E-mails, and delivered one to [EMAIL PROTECTED], and the other to [EMAIL PROTECTED] I can't see any way that qmail would be able to deliver to two different addresses unless it was given two different addresses. -Scott --- Declude: Anti-virus, Anti-spam and Anti-hijacking solutions for IMail. http://www.declude.com --- [This E-mail was scanned for viruses by Declude Virus (http://www.declude.com)] Please visit http://www.ipswitch.com/support/mailing-lists.html to be removed from this list. An Archive of this list is available at: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Please visit the Knowledge Base for answers to frequently asked questions: http://www.ipswitch.com/support/IMail/ Please visit http://www.ipswitch.com/support/mailing-lists.html to be removed from this list. An Archive of this list is available at: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Please visit the Knowledge Base for answers to frequently asked questions: http://www.ipswitch.com/support/IMail/
