So I am trying to get mailcow to accept mails on port 25 from a particular server (Rocket.Chat) that I just can’t get to connect via port 587 (or 465) no matter what I try.
It is my understanding (got help from this community) that I need to add the network of the recalcitrant server to trusted networks in postfix (data/conf/postfix/extra.cf).
I followed the example in https://mailcow.github.io/mailcow-dockerized-docs/manual-guides/Postfix/u_e-postfix-trust_networks/ but I left out all the IPV6 addresses (as I am not using IPV6). So I ended up adding “127.0.0.0/8 172.22.1.0/24 192.168.99.0/24” with the latter one being the network Rocket.Chat is on.
But when I now try to send an email, instead of “Relay access denied” I get “Temporary lookup failure”.
So apparently, I made a mistake. Can someone explain what it is?