Hi guys, I am having an issue with Postfix and hope members can help. We have been looking for ways to send external mail to a secondary smart host if our primary exchange server goes down. Ex: Transport file:
If mailtest goes down we need to find a new host to relay to. So I discovered the smtp_fallback_relay directive which is perfect and does the job we were looking for by allowing us to define:
smtp_fallback_relay = [192.168.99.100]
However we are seeing issues were mail from internal hosts from exchange destined towards external unreachable mail servers are also getting relayed back to our smtp_fallback_relay. Ex: I send message to firstname.lastname@example.org
and the server rejects the message it will come back to our exchange host. How do I only use the smtp_fallback_relay for inbound mail messages only and exclude outbound mail from the exchange servers from using the fallback directive?