Hi RobertoWe have tried to do something like B with NS7but found the NS server answers to smtp so internal emails would then bounce between the servers. Did you test outgoing emails?Still testing if we should uninstall dovecot etc as it has a property for smtp, pop, imap.
Splitted from http://community.nethserver.org/t/nethserver-as-antispam-antivirus-gateway-to-your-mail-server/283/10
Ehi Gordon,did you check this howto? Take a look and let me know