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

Joseph Brennan brennan at columbia.edu
Tue Nov 5 15:11:28 CET 2013

--On November 5, 2013 10:25:20 AM +0100 Ralf Hildebrandt 
<Ralf.Hildebrandt at charite.de> wrote:

> Who's to blame? Mailman for re-using the message-id? Exchange for
> dropping the second mail on the floor?

The messages are duplicates, so they should have the same Message-ID.

Whether to suppress delivery of duplicates is the choice of an end user, or 
a system administrator, or a software designer. I don't know which applies 
to Exchange. But in order to allow the choice, which is correctly a choice 
to be made at the receiving end, the dups have to be sent with the same 

I wouldn't say 'blame'.

Joseph Brennan
Columbia University I T

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