Hi Ansgar,
On 2015-04-16 Ansgar Wiechers wrote:
If someone sends a mail to group1@ and group2@ the user2@ gets two
copies of the same mail. Back then, when we used Cyrus there was a
feature called "duplicatesuppression" that did the trick, but Dovecot
does not seem to have such feature.
This should probably be asked on the respective Dovecot mailing list,
since it's an MDA rather than an MTA problem. I don't think you can
suppress these duplicates in Postfix, because the MTA correctly receives
and delivers two separate transmissions (one for group1, the other for
group2).
(1) No, Postfix receives exactly one mail/transmission.
As said, the "enable_original_recipient" option does the trick,
but not in conjunction with recipient verification.
Ideally I would like to prevent the generation of duplicates by
Postfix' virtual_alias_maps rather than deleting them afterwards.
(2) For Dovecot there are several mailing list threads, where the
conclusion was something like "Duplicate elimination is not
implemented/needed. Please fix your MTA config!" ;)
https://mail.python.org/pipermail/mailman-users/2010-January/068248.html
http://www.dovecot.org/list/dovecot/2011-March/057943.html
http://www.dovecot.org/list/dovecot/2010-January/045887.html
http://www.dovecot.org/list/dovecot/2008-December/035678.html
(3) Eventually, I just want to avoid backscatter, thus configuring
Postfix in a way that does recipient verification only for
addresses that are no keys in virtual_alias_maps would be
sufficient, too.
When I add an alias I'm pretty sure I want to receive mails for
that address, regardless of the actual alias targets.
(4) At the moment I'm trying to implement a solution with postmulti,
but this is a nightmare as main.cf lacks of an "include" directive
and I would have to manually keep the configs in sync :(
Thanks,
Mathias.
