Zimbra Cluster - Sender Domain

[Klug]

These are parts of your log file, not the headers of the mails sent.
I've checked in the headers of the mail sent by my customer's cluster and the nodes do not appear.

Do you have a reverse entry in your DNS (or your ISP DNS) for the external mx.domain.tld record ?

[briansrapier]

Yes, I do.

10.56.xxx.xxx.IN-ADDR.ARPA. IN PTR mx.domain.com.

[Klug]

That's a private IP, I guess this reverse record is in your internal DNS.
My question is about the external record.

[briansrapier]

No, that's not internal. That is the reverse lookup address. The address ends in .56.10 for the external address.

I'm concerned about posting domain name specifics here, so I'll PM you.

[Klug]

Oops, my mistake, sorry.
Forgot to read it reverse 8-(