From: DG on
in real first rule win, so this should work but remember to configure
smtpd_sasl_
smtpd_recipient_restrictions =
permit_sasl_authenticated,
permit_mynetworks,
reject_unauth_destination,

smtpd_client_restrictions =
permit_sasl_authenticated,
reject_unknown_address,
reject_unknown_client,
reject_unknown_reverse_client_hostname,
check_client_access hash:/etc/postfix/access,
reject_rbl_client sbl-xbl.spamhaus.org