Mailing List Message #6433
From: Matt Simpson <>
Subject: Re: spam and message ids
Date: Thu, 6 Jul 2000 21:11:56 -0400
To: SIMS Discussions <>
At 4:04 PM -0600 7/6/00, Kreme wrote:
I would say the vast majority of regular email will have the
Message-ID.  However, a lot of mailing list mail will not.  And even if it
does, the message ID does not match the From:

I use one of the popular Macintosh list servers (Macjordomo), and its solution to Message-ID seems reasonable. If the incoming message has a Message-ID, it will retain that same message-id on the outbound one. If there is no message id, it does not add one.  Since the From: has the address of the individual sender, the message-id and From: usually do match. In my (limited) experience, the vast majority of the mail that passes through my server has a message-id; occasionally one does not.

I've run into sites (poorly run ones) that bounce email as spam if it did
not contain a "correct" Message-ID.  Ended up having to blacklist several
and explain the failure to the mailing list subscribers.

I ran into one of these once.  They bounced the mail without explaining why. I couldn't figure out why some messages bounced and most didn't. I dropped the subscriber and told them it was because their ISP was bouncing mail for no apparent reason. They asked the ISP, who responded that it was because of the missing message-id and I "should fix my system to comply with the RFCs".
I responded that my system wasn't broken, the RFC said the message-id was optional, and it wasn't my responsibility to add it.  Since continuing to let the mail bounce was not an acceptable option for me, I figured I had a choice of blacklisting the subscribers who were incorrectly bouncing the mail, which was easy and seemed fair, or blacklisting the subscribers who were sending mail without message-ids, which was a little tougher to identify and seemed less fair.
As a way of fighting spam, this seemed a little silly. I've never checked to see how much spam contains message-ids, but I'll bet a lot of it does. And if more ISPs started blocking mail without message-ids, I bet more spammers would start adding them. It really doesn't seem like a very strong defense.

At 3:49 PM -0700 7/6/00, Daniel Solomons wrote:
We have to remain compatible with with the rest of the world, even
when they're "wrong".... :-)

It's usally nice to remain as compatible as possible, but in a situation like the above, you sometimes get caught in the middle. As I explained to the subscriber and their ISP, if the messages they were rejecting had been sent as individual messages directly from the sender, instead of through my list server, they still would have been rejected. So they were rejecting legitimate mail because of a problem I did not cause and could not fix.  That's pretty "wrong" and there really wasn't any way for me to remain compatible.

Matt Simpson --  Obsolete MVS Guy
University Of Kentucky, Lexington, KY
<>     <>
He who laughs, lasts.
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