I have done this:
From internet to PMG : Port 25
From PMG to internet : Port 25
And in postfix mail server, a transport layer has been configured as
* smtp:192.168.0.142:26
And in Virtualmin I have allowed port 26 in firewalld.
I have one static IP, with one server running Proxmox VE.
I have installed Virtualmin for mail server and Proxmox Mail Gateway.
I forwarded the port 25 to PMG. I created a transport map in postfix to PMG.
Outgoing mails are fine. Incoming mails are getting bounced back.
Error...