[Kolab-devel] [issue2] document running mail domain partly

[Bernhard Reiter]

New submission from Bernhard Reiter <bernhard at intevation.de>:

It would be nice to have it documented how
to have a part of the users of one mail domain run on Kolab
and the other running on another MTA, like Exchange.

This sound trivial in the beginning, but the problem is
that most MTAs and Cyrus IMAPD getting mail per lmtp
will only accept mail if it is clear for their mail domain
and nothing else.

So if we declare the Kolab server as the main MTA
with its postfix, we run into the problem that postfix
could rewrite incoming emails according to some pattern,
but can only deliver mail to a single domain to a single transport.

Example user a on Kolab and user b on Other MTA.
Our mail domain is mail.xx.

Postfix accepts  a at mail.xx and b at mail.xx.
Now we want b at mail.xx to be relayed to OtherMTA
as opposed to local lmtp delivery for a at mail.xx.

Postfix could rewrite a at mail.xx to a at local.mail.xx
or rewrite b at mail.xx to b.othermta.mail.xx
to split the transports. However both cyrus imapd
and OtherMTA will not accept that other mail domain.

A possible solution would be to add an option to 
postfix lmtp transport part to drop "local" from
the domain again.

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messages: 2
nosy: bernhard
priority: wish
status: unread
title: document running mail domain partly
topic: server
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