Miscellany

smtpd_recipient_restrictions =
            permit_mynetworks,
            # permit_sasl_authenticated,
            reject_invalid_hostname,
            reject_non_fqdn_hostname,
            reject_non_fqdn_sender,
            reject_non_fqdn_recipient,
            reject_unknown_sender_domain,
            reject_unknown_recipient_domain,
            reject_unauth_pipelining,
            permit_mynetworks,
             reject_unauth_destination,
        #    reject_rbl_client zombie.dnsbl.sorbs.net,
        #    reject_rbl_client relays.ordb.org,
        #    reject_rbl_client opm.blitzed.org,
        #    reject_rbl_client list.dsbl.org,
        #    reject_rbl_client sbl.spamhaus.org,
            permita