Never mind.. I figured it out: in main.cf: transport_maps = hash:$config_directory/tables/smtp_transport_maps
smtpd_recipient_restrictions =
...
check_recipient_access
hash:$config_directory/tables/smtpd_allow_nullroute
...
tables/smtpd_allow_nullroute:
nullro...@mydomain.net permit
tables/smtp_transport_maps:
nullro...@mydomain.net discard:
Ville
