On Wed, Nov 28, 2018 at 09:56:19PM +0100, Stefan Bauer wrote:
> Is there a way to keep an smtp session open and do before queue filtering
> AND final delivery to remote mta? do only sent 250 if we have already
> received 250. if not send temp error.
Only if there is a fixed remote MTA (smarthost), regardless of the
ultimate destination domain, and that MTA never selectively rejects
just a proper subset of the recipients.
Postfix can provide a non-queueing SMTP proxy, but only when the
fixed nexthop smarthost MTA accepts everything that Postfix accepts,
or else rejects the entire message, and it supports largely the
same ESMTP features (but you can configure which ESMTP features
Postfix will advertise to match).
If Postfix is to perform non-trivial message routing or address
rewriting, then the answer is "no".
--
Viktor.
