On 02/04/2020 15:18, Adam Raszkiewicz wrote:
Desired flow looks like:
Dovecot ---------------------> Postfix --> Relay Server -┐ Dovecot <-- LMTP/LDA <-- Postfix <---------------------┘
This mail flow cannot work with one Postfix instance. Either Postfix knows that "localdomain.com" is local and should be delivered to the LDA, in which case it won't be forwarded to the relay server, or Postfix does not know that "localdomain.com" is a local address and therefor forwards it the relay server, but than it will do that anytime it sees "localdomain.com".
Only possibility is to run two instances of Postfix.
The real question is: Why do you want this mail flow? Where is the benefit in sending a local mail out to a relay server only to get it back and deliver it?
Cheers, Juri