Setup Secondary Mail Relay

[kilburn]

Quote:BTW - temporarily setting the relay domain as IN MX 5 relay.domain.tld. in DNS...
Is that a valid test? It should then forward on...

Code:

domain.tld. IN MX 5 relay.domain.tld.
domain.tld. IN MX 10 mail.domain.tld.

Hmmm... I don't remember how did you assign the DNS records, so double answer here:

1. If relay.domain.tld points to the panel
Invalid test. Postfix will think that it's the main server, but as you told it that this domain isn't local, it won't know what to do with the messages and thus it will generate failure DSNs.

2. If mail.domain.tld points to the panel
This is the good setup. As the final server is the preferred one, postfix will know what to do with mails for that domain (relay them to the primary) and everything should work fine and wonderfully.

The easiest way to test the setup is manually sending an e-mail through telnet, like (server answers omitted, but you will get feedback to this commands):

Code:

telnet mail.domain.tld 25
ehlo me.com
mail from: me@me.com
rcpt to: recipient@domain.tld
data
Subject: testing
Testing
.

Just look at the responses you get during the process (relay denied, whatever).