smtpd_sasl_auth_enable = yes
smtpd_recipient_restrictions = permit_sasl_authenticated , reject, check_relay_domains
smtpd_sasl_authenticated_header = yes
smtpd_client_restrictions = permit_sasl_authenticated
smtpd_sasl_security_options = noanonymous
smtpd_sasl_application_name = smtpd
smtpd_use_tls = yes