mtpd_helo_required = yes

smtpd_helo_restrictions =
    reject_invalid_hostname,
    reject_non_fqdn_hostname,
    permit

smtpd_sender_restrictions =
    reject_unknown_sender_domain,
    reject_non_fqdn_sender,
    permit

smtpd_recipient_restrictions =
    reject_unauth_destination,
    reject_non_fqdn_recipient,
    reject_unknown_recipient_domain,
    check_policy_service inet:127.0.0.1:60000 #postgrey
    permit

smtpd_client_restrictions =
    reject_invalid_hostname,
    permit