Mail Archives: cygwin/2008/10/24/13:06:07
On 24 Oct 2008 10:30:08 +0200, Corinna Vinschen wrote:
> we have a strange mail duplication here on the cygwin ML. The
> mail with Message ID <0ML4cO-1Kt7yy1h2s-000U3k AT mx DOT kundenserver DOT de>
> is duplicated over and over again. Could something on sourceware
> be the culprit?
Now that is interesting! I see the message come back to me with no
Message-ID in the headers (sample included below, with '@' and '.'
replaced to protect the innocent).
I have a theory as to what's going on...
I believe that adding the Message-ID field is the responsibility of the
MUA. But some mail servers add a Message-ID if it is missing. I just
verified that my MUA was not creating the Message-ID field, and I'm
guessing that one got added somewhere along the way to Corinna's mailbox.
I don't think that the missing Message-ID is the root cause of the mail
duplication problem. But I do believe that the missing Message-ID causes
the workaround to the problem to fail. I'm guessing that the
sourceware.org server may detect and prevent duplicated messages based on
the Message-ID field. But since there wasn't one in my message, that
mechanism did not work.
(I've got a hunch that the root cause may be some miscommunication between
the servers due to timeouts or something, but I have no way to verify
that).
In any case, if my guess about the misssing Message-ID is correct, then
I believe that a few of things should be done:
1) I should make sure that my MUA generates the Message-ID field on
outgoing messages. I believe that I have fixed this now (and this
message should have a "@maeder.org" Message-ID).
2) If the cygwin mail server is truly depending on Message-ID to stop
this message duplication, it should somehow ensure that it is always
there. One option would be to prevent posts to the list that are
missing the Message-ID field (with some reasonable return error
message to the sender). NOTE: I'm not sure if generating a Message-ID
field on the cygwin mail server would work (that might just add
a unique Message-ID on each duplicated message, I'm not sure).
3) Determine and fix the root of the duplication problem (though I'm not
sure how feasible this would really be).
I think most modern MUA's add the Message-ID field, but it is not a strict
requirement. Implementing something for 2) above may help avoid the
duplication problem for mail sent from misconfigured and/or old school mail
clients (nmh in my case).
How to stop the still repeating evil message? I still haven't a clue...
Herb.
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To: cygwin AT cygwin DOT com
From: Herb Maeder <maeder-cygml AT maeder DOT org>
In-reply-to: "Manning, Sid" <sidneym AT qualcomm DOT com> 's message of Mon, 20 Oct 2008 11:53:19 PDT.
Subject: Re: Compile time Local Cygwin vs. VMware session on same system
Date: Thu, 23 Oct 2008 13:43:30 -0700
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