[Mailman-Users] Mailman reusing message-id, leads to duplicate message suppression

[Ralf Hildebrandt]

* Richard Damon <Richard at Damon-Family.org>:

> This is really a tough problem. Presumably, since mailman doesn't
> significantly alter the message (which is one reason it is allowed to
> maintain the message-id) it should really matter that the recipient only
> gets one copy of the message, or which one.

Yes, only the Subject is slightly being altered.
 
> The idea of dropping second copies of messages also can make some sense,
> if you already have a message, do you really need a second copy? This is
> almost absolutely right if the two copies are due to being listed twice
> in the distribution, or the duplication due to automatic verbatim
> forwarding from one address to another. It isn't quite so for sure in
> the case of mailing list, or if the user wanted to compare things like
> received headers to compare path ways. I suspect that the people
> implementing this feature really didn't think about the mailing list case.

Or the users wants to check if the message has indeed been distributed
via two or more mailing lists!

> In conclusion, the fault probably is on the mail system, but they can
> probably claim they had good reasons to do it. Hopefully there is a way
> to turn off the option if really needed.

There's not way of turning this off on Exchange