On Sun, Jun 16, 2019 at 04:00:38PM +0200, Stefan Bauer wrote:
> We are running a small smtp relay service with postfix for authenticated
> users. Unfortunately office 365 does not offer any smtp authentication
> mechanism when sending mails via connectors to smarthosts.
There's a giant gap between the first sentence and the second.
You'll need to explain the use-case in considerably more detail.
Why does Office365 elect to use your relay at all? Do they limit
the traffic so routed to just the authorized users? Are you sure
they can't/won't use a SASL login or TLS client cert to authenticate,
in this context.
There's no magic, Postfix can only authorize based on IP address,
SASL or TLS auth, possibly further constrained by sender address
(which is never sufficient in isolation).
--
Viktor.
