smtpd_delay_reject = yes
smtpd_helo_required = yes

smtpd_helo_restrictions =
    permit_mynetworks,
    check_helo_access hash:/usr/local/etc/postfix/helo_access,
    permit

smtpd_sender_restrictions =
    permit_mynetworks,
    reject_non_fqdn_sender,
    reject_unknown_sender_domain,
    permit_sasl_authenticated,
    check_policy_service unix:private/spf,
    reject_unverified_sender

smtpd_recipient_restrictions =
    reject_unlisted_recipient,
    permit_mynetworks,
    permit_sasl_authenticated,
    reject_unauth_destination