Tutorial to build a linux mailserver with virtual users support using Debian, Postfix, Dovecot, MariaDB and other software packages. - scattercz/debian-postfix-dovecot-mariadb-mailserver-tutorial ...
This tutorial shows you how to setup Postfix (smtp server) and Dovecot (imap/pop server). The task of the smtp server is to accept incoming mails and relay outgoing mails from authorised users on the ...
if you just want to forward email thats comming to one user account you should be able to create an alias. In debian I place this in /etc/mail/aliases I dont know for sure about the second option but ...