Permitting authenticated users

If you are already using the smtpd_recipient_restrictions parameter as part of your UBE blocking, you have to tell Postfix to allow authenticated users to relay by adding permit_sasl_authenticated to the list of restrictions. If you were previously using the default and didn’t need a smtpd_recipient_restrictions parameter, just add the following line:

smtpd_recipient_restrictions = permit_mynetworks,
    permit_sasl_authenticated, reject_unauth_destination

If you are already using the smtpd_recipient_restrictions parameter, just add permit_sasl_authenticated to the list of restrictions. Be sure to include some kind of rejection restriction in your list (see Chapter 11).