(off-topic) Outlook 2003 msgids causing odd email problems

[Jonathan McKeown]

I'm raising this here in case anyone else has either seen this problem and has 
any thoughts, or alternatively has experienced the fallout and is wondering 
why.

Over the last few weeks I've had complaints that email messages are going 
astray. This has happened in Cyrus imapd on delivery, and in Mailman, where 
archiving of posts is sometimes broken.

After much scratching of head and tearing of hair, I have finally found two 
provable instances - one in Cyrus and one in Mailman - of replies to messages 
being sent using Microsoft Outlook Service Pack 2, where Outlook has given 
the reply the same message-id as the message it is replying to - in flat 
violation of RFC{2}822. (In one case the original message, the read-receipt 
automatically generated by Outlook, the reply, and the forward of the reply 
sent when the reply didn't arrive, all had the same msg-id).

As far as I can tell this behaviour was introduced by SP2; the Web says 
Outlook 2003 before that didn't add message-ids at all.

I've now set

duplicatesuppression no

in imapd.conf which seems to be addressing the problem of lmtpd discarding the 
``duplicate'' messages. Mailman is another issue.

I haven't seen any discussion of this problem on the Web: has anyone else 
encountered it? Better yet, does anyone have a fix (on the Microsoft side)?

Jonathan