> Is this an incoming relay or an outgoing relay (define mailscanner). > There is a "relay_domains" keyword as well as "mydestination" and > "mynetworks". Also, check out *_restriction variables. It is an incoming relay. I was aware of the relay_domains tag, and thought I had it right, but am still getting the errors I mentioned. In /etc/postfix I set up transport, and relay_domains. In transport my syntax is: .domain.com smtp:[x.x.x.x] In relay_domains I have the domains allowed as: domain.com RELAY -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.