[Dovecot] Duplicate Elimination

Frank Cusack frank+lists/dovecot at linetwo.net
Thu Feb 25 00:00:26 EET 2010

On 2/24/10 4:51 PM +0200 Timo Sirainen wrote:
> On 24.2.2010, at 16.15, Steffen Kaiser wrote:
>>> group1: user1 at example.com,user2 at example.com
>>> group2: user1 at example.com,user3 at example.com
>>> If i am sending a mail to group1 and group2. It is going two times a
>>> single mail to the user1 mailbox. But in dovecot it is not eliminating
>>> since it has the same message-id. Previously i was able to accomplish
>>> this task with cyrus duplicate elimination.

If this is the only dup concern, you "just" need to have the MTA
unalias the recipients before delivery.  sendmail, e.g., does it that

If your dup concern is more general, e.g. a direct reply plus a mailing
list reply, the above obviously won't change things.

>  (I hate the whole concept of dropping incoming messages as duplicates
> based on Message-ID. I would definitely want it disabled for my own
> mails, for example that would mean I couldn't filter messages to mailing
> lists based on List-ID: header, because the first mail usually comes
> directly from the other user, and then the second mail with the List-ID:
> would get dropped.)

Not a problem if you filter on List-ID, at least not a problem with
how cyrus handles duplicate elimination.  It only eliminates duplicates
in the same mailbox.  If you filter on List-ID, each message would go
to a different mailbox and you would receive both.

I think "hate" is a bit strong, yes?


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