not arriving emails, duplicate suppression, message-id

[Simon Matter]

> Dear list,
>
> Today I got a support ticket claiming that some mail was not arriving in
> a persons mailbox.
>
> Sure enough when I went trough all our postfix and cyrus logs I could
> see that the email was certainly delivered to our mail store.
>
> It was the duplicate delivery that eliminated duplicate message.
>
> When I grepped in the mailbox after that message id I could find an
> other totally different message with the same id.
>
> The only thing that both message had in common was that they were both
> created with Microsoft Outlook 12 and 11.
>
> I thought that the message-id should be unique.

Outlook is broken, it sends new mails with existing message-id under
certain circumstances (for example when resending an already sent mail to
other receivers). Microsoft has fixed this - in their MTA on exchange! No
joke, when sending mail from Outlook to Exchange via SMTP the Exchange
server will always regenerate a uniq message-id.
I don't have a fix, only an explanation.

Simon

>
> Has any body seen this before?
>
> I couldn't find any info on the net how it is generated by Outlook.
> Maybe it is a setting that can be changed?
>
> Thanks in advance,
>
>
> --
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> Rudy Gevaert          Rudy.Gevaert at UGent.be          tel:+32 9 264 4734
> Directie ICT, afd. Infrastructuur ICT Department, Infrastructure office
> Groep Systemen                    Systems group
> Universiteit Gent                 Ghent University
> Krijgslaan 281, gebouw S9, 9000 Gent, Belgie               www.UGent.be
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