My smtp servers domain(origin) is xxx.com. When I try to email email@example.com from smtp server, it does not deliver that mail since this user51 is not hosted on this smtp server. user51 has an google apps account with domain xxx.com
So I want smtp server to deliver mail remotely if that user is not hosted locally.
How is that possible with postfix?
# mydomain relayhost = $mydomain # relay_domains