Jeroen said: My personal server uses:
smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination, reject_unknown_reverse_client_hostname, warn_if_reject reject_non_fqdn_helo_hostname, warn_if_reject reject_invalid_helo_hostname, warn_if_reject reject_unknown_helo_hostname, reject_unauth_pipelining, reject_non_fqdn_sender, reject_unknown_sender_domain, reject_non_fqdn_recipient, reject_unknown_recipient_domain, check_helo_access hash:/etc/postfix/helo_access, permit Out of curiosity, does anyone see any drawbacks (such as possibly rejecting valid mail) to adding "reject_invalid_hostname" to those smtpd_recipient_restrictions? Also, some other reading I've been doing suggest adding "smtpd_helo_required = yes" to the main.cf file. Is that helpful/necessary, or would I already be covered there with the "reject_invalid_helo_hostname" in the above recipient restrictions? I've also read another suggestion to add "smtpd_sender_restrictions = reject_unknown_address" to reject mail that doesn't have any return address. I've moved all my checks to the recipient restrictions, so if I added this, it would be my only sender restriction. Am I wrong in thinking this check is superfluous because of the "reject_non_fqdn_sender" already in the above recipient restrictions? It's slowly starting to make more sense. Thanks again to those who have given me helpful nudges. Thanks, Steve