So I've managed to setup bind9 and a mail server, but it seems there is something wrong. I don't quite under stand this error: The configuration of your mail servers and your DNS are not ok! The report of the test is: mail.domain.com. - mail.domain.com - 208.xxx.xxx.xxx - lisa.domain.com Spam recognition software and RFC821 4.3 (also RFC2821 4.3.1) state that the hostname given in the SMTP greeting MUST have an A record pointing back to the same server. Can anyone explain this to me in a bit more detail, and maybe point me in a direction to solve this?