For example, I have an ONT optical fiber with two Ports.
Port 1 connects to the router (Int IP: 192.168.0.1) (Ext IP: 190.6.206.171), the router assigns me an internal IP for the Web Server (192.168.0.11 -> 190.6.206.171).
Port 2 connects to the mail server (Ext IP: 190.6.206.173).
How difficult here, I need all the webserver send mails (192.168.0.11) THROUGH send them mail server (190.6.206.173)
Any Idea :) ?