On Mon, 30 Sep 2024, Quelrond wrote:
Unfortunately, we are in a corporate environment that we cannot control. We
MUST use this relay server that don't accept empty 'From' for outbound
mailing.
My sympathies. That is SO stupid.
My recommendation: instead of empty MAIL FROM, send NDR as
MAIL FROM n...@example.com. Simple and sweet. Be sure to drop any
incoming mail to n...@example.com to avoid the mail loops. Still wastes
time and bandwidth coming all the way back to you - but that is on the stupid
corporate policy. At least you break the loop.
The only thing that we can do is to send NDR directly to the destination. As
in 99% this is our internal addresses, and in 90% this is ~3 pre-defined
addresses - we can send these NDR directly to our internal mail server, it
will deliver these NDR to the internal mailboxes. But I don't know OpenSMTPD
so good to configure it at this manner.
That is a good optimization, but just doing the above will get things
going. You'll need a table of which domains to do real NDRs.
