Identity The Postfix mail server has 4 major identity features that will need to be considered. These identity features are very important in terms how the server is able to communicate on the Internet because it is so closely tied to DNS, just like all mail servers. myhostname Postfix requires a fully qualified domain name or FQDN. A FQDN includes the hostname of the server as well as the domain name like this: mail.example.org This includes the ...