Hello! I have production mail server, running ubuntu 10.04 and postfix. Succesfully working for years, now it`s overloaded. I want to split it in to 2 servers - mail gateway for anti-spam, anti-virus checks, and mail system for sending e-mails and for imap folders. In my test environment it works somehow with 1 domain, but when im trying to reproduce it from scratch with virtual domains, I always have "Undelivered Mail Returned to Sender" with "mail for xxx.xxx.xxx.xxx loops back to myself". I remember, that there was exactly same error in my first test installation, but don`t remember how to fix it, and I don`t describe it in my documentation (stupid me, yes!). So, my questions is: 1). how to fix this error? 2). What DNS settings are right for me? Now I have 1 server as primary MX for domains domain.example.com, and domain2.example.pro with 1 public ip, and A- and MX- records in both domains, (mail.domain.example.com + mail.domain2.example.pro) and with 1 PTR record "mail.domain.example.com". When I add gateway, should I set it up with two public ip`s, with 2 FQDN, 2 MX records in my domains and with 2 PTR records for each FQDN, or 1 FQDN, 2 MX, 1 PTR is enough? 3). If i Set it up with 2 FQDN, what to use as myhostname in main.cf? Can postfix use both depending on sender domain or somehow else? Thanks!