[Pkg-exim4-users] Exim, Sympa Mailing list manager and broken threading with added Message-ID to messages with no Message-ID from Outlook

[Andreas Metzler]

Paul Menzel <paulepanter at users.sourceforge.net> wrote:
> Dear list,

> I am using Sympa [1], Exim 4 from Debian Lenny. Yesterday I noticed that
> an answer to a message on the list was not threaded correctly. It turns
> out that the message id in my copy of the original message was different
> than the message id from the message of the replier.

> The original message was written with Outlook.

> X-Mailer: Microsoft Office Outlook, Build 11.0.5510

> It looks like that Outlook does not add a message id to a message if not
> delivered by Exchange [2].

> Now the problem is that Sympa seems to queue(?) each message for a
> recipient/subscriber of the list separately so that Exim adds a
> different message id to each copy of the message for each subscriber.

> Does anyone know a solution for this problem?
[...]

Hello,
The most obvious way[1] is probably to add the Message-ID before the
message is passed on to sympa.

You could use something like

warn 
[...specific conditions for messages passed on to sympa]
control = submission/sender_retain

in the ACLs to do this.

cu andreas

[1] The only other thing I can think of is making exim not add
Messsage-IDs to sympa-generated outgoing mail, but that will break
threading even worse, since the individual copies will either no
Message-Ids or differeing ones, added by the final recipient's MTA.
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