What are you doing that has you running multiple instances of Postfix?
I think I’ve only ever run multiple MTAs on one system once or twice in the last 25 years.
And that was to deal with some very special MSA to MTA situation.
Otherwise I’ve always been able to use a single MTA.
@daedalus fair enough.
Using multiple simpler configurations verses one more complex configuration is something that I’ve done multiple times.
I currently have multiple routers with two interfaces; inside and outside vs three or more interfaces; out0, out1, lan0, lan1, lan2, for the very reason you’re talking about multiple MTAs.
Have you considered multiple systems, each with one MTA? Taking the reason you’re describing to the next logical level.
I’m just talking hypothetical and trying to learn from your efforts.
Thank you for explaining. 🙂