I was wondering if it would be possible to use a different outbound mail IP address instead of using the main IP of the server?
If so, a guide on how to do this would be awesome!
You can use SNAT_TO_SOURCE and SNAT6_TO_SOURCE in your Mailcow config, but that will affect all outbound traffic from Mailcow, not just email. Is that OK for your use case?
Docs here: https://mailcow.github.io/mailcow-dockerized-docs/firststeps-snat/
Any idea how I can use 2 outbound IPs for Postfix Mail SMTP out?