On Fri, Jul 05, 2013 at 10:00:02AM -0400, W T Riker wrote: > Thanks for that explanation. I think I understand the way it works now > so I modified my restrictions a bit. Does this order pass the sniff test? > > smtpd_recipient_restrictions = > reject_non_fqdn_recipient, > reject_non_fqdn_sender, > reject_unlisted_recipient, > permit_mynetworks, > permit_sasl_authenticated, > reject_unauth_destination, > reject_invalid_helo_hostname, > reject_unknown_sender_domain,
Fine up to here. > reject_unknown_recipient_domain This is not a good idea in this context, you've already checked the message is to one of your own domains. Unless you've specified relay_domains (and you have relay_domains listed in parent_domain_mathes_subdomains) or inherit relay_domains via its default $mydestination, every domain you accept should be "known", you just risk deferring mail due to transient DNS lookup errors. You should generally avoid having subdomain matching in relay_domains, set parent_domain_matches_subdomains empty or perhaps just: parent_domain_matches_subdomains = smtpd_access_maps if your access tables rely on this to match a domain and all its subdomains. The backwards compatible default is: parent_domain_matches_subdomains = debug_peer_list, fast_flush_domains, mynetworks, permit_mx_backup_networks, qmqpd_authorized_clients, relay_domains, smtpd_access_maps -- Viktor.