[SOLVED] wierd dns errors while installing

[deltatango]

I am about to install a new Zimbra server (Network Edition, Mac OS 10.4. Server), which will replace the old one still in use.
For being able to restore the old server's contents, I have to give the new server the same hostname as the old one (mail.example.com). Thus I've set up a DNS server on the machine with a fake example.com zone and configured the system to use this DNS server. Yes, that's odd, but according to the documentation, the hostnames of old and new server have to be identical.

But when I run the installer I get this:
> DNS ERROR resolving MX for mail.example.com
> It is suggested that the domain name have an MX record configured in DNS
> Change domain name? [Yes]

I type "no". I then get consecutive error messages like
"Setting zimbraSmtpHostname for mail.example.com...failed.

Yet, when I check it, everything is ok:

$ hostname
mail.example.com

$ dig example.com mx
[...]
;; ANSWER SECTION:
example.com. 86400 IN MX 10 mail.example.com.

;; AUTHORITY SECTION:
example.com. 86400 IN NS mail.example.com.

;; ADDITIONAL SECTION:
mail.example.com. 86400 IN A 192.168.35.249

$ host 192.168.35.249
249.35.168.192.in-addr.arpa domain name pointer mail.example.com.

What am I missing here?
Can I restore the new server from backup also with a different hostname?

[Bill Brock]

question regarding changing domain. Then change from mail.example.com to example.com.

[deltatango]

question regarding changing domain. Then change from mail.example.com to example.com.

OK, that did solve it. Thanks, Bill