# client # sender # recipient # relay smtpd_client_restrictions smtpd_sender_restrictions smtpd_recipient_restrictions smtpd_relay_restrictions smtpd_helo_restrictions smtpd_data_restrictions smtpd_end_of_data_restrictions smtpd_etrn_restrictions my_networks= my_hostname= smtpd_helo_required=yes # unknown reject_unknown_client reject_unknown_client_hostname reject_unknown_reverse_client_hostname reject_unknown_helo_hostname reject_unknown_sender_domain reject_unknown_recipient_domain reject_unknown_hostname # hostname reject_unknown_client_hostname reject_unknown_reverse_client_hostname reject_unknown_helo_hostname reject_unknown_hostname reject_invalid_hostname reject_non_fqdn_hostname # fqdn reject_non_fqdn_sender reject_non_fqdn_recipient reject_non_fqdn_hostname # sender reject_non_fqdn_sender reject_unknown_sender_domain # recipient reject_non_fqdn_recipient reject_unknown_recipient_domain reject_unauth_pipelining check_policy_service