I'm running Postfix/Dovecot as part of my CentOS 5 Perfect Setup on a test server behind a firewall on a LAN. Is there a way to limit Postfix so that it does not try to send or receive any mail outside my LAN? My ISP blocks port 25 so there's no point in Postfix trying to send anything in the first place. I am just using Postfix/Dovecot to monitor LAN emails from other computers on the LAN.
Make sure that the domains for which the server should not handle emails are not listed in mydestination in /etc/postfix/main.cf.
