I have already setup the ISPCONFIG auto Installer on Ubuntu 18.04. Now I want to use separate IP for mail, is that possible? if yes, how I can do that? Thanks.
Configure the IP adress in /etc/network/interfaces Then configure postfix: http://www.postfix.org/postconf.5.html#inet_interfaces
After configuring your network interface, add the IP addresses under System > Server IP to make them available for the websites in ISPConfig.
Having multiple IP-addresses on a host is called multi homing. Use Internet Search Engines with Code: multi homed host linux to learn more.
