misterious duplicate message-id

Adam Tauno Williams awilliam at whitemice.org
Thu May 7 10:19:46 EDT 2009

On Thu, 2009-05-07 at 15:45 +0200, Sebastian Hagedorn wrote:
> --On 7. Mai 2009 13:13:24 +0200 Gabriele Bulfon <gbulfon at sonicle.com> wrote:
> > as a follow up to my "finding by message id" message, I found the reason
> > why that message was silently discarded: for 3 times that Outlook user
> > could send an email with the exact same message-id generated by Outlook!
> > How is it possible?!
> That's a known Outlook bug. I don't recall the precise circumstances, but 
> I've seen that again and again.

If you do a re-send in Outlook it seems to resend the *exact* message,
including Message-ID.  The "fix" for this is to use M$-Exchange 2000 SP1
or later;  their MTA (on the server) rewrites the Message-ID of the
submitted message to a unique value.

Someone told me there is an issue with re-using Message-IDs in the DSN
functionality too, but I've never seen that one.
OpenGroupware developer: awilliam at whitemice.org
OpenGroupare & Cyrus IMAPd documenation @

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