On Linux servers behind NAT you will start getting emails warning that the DNS setup is broken.
cPanel states that the panel does not work behind NAT and the boxes need public ip addresses.
It seems that apart from this warning the panel and services function fine behind NAT (as expected) and while I wouldn't recommend it, sometimes you have no choice.
The email you get though is something like the following:
[ipcheck] Problem with DNS setup on myserver.local IMPORTANT: Do not ignore this email. The hostname (myserver.local) resolves to 10.0.0.1. It should resolve to 192.168.0.1. Please be sure to correct /etc/hosts as well as the 'A' entry in zone file for the domain. Some are all of these problems can be caused by /etc/resolv.conf being setup incorrectly. Please check this file if you believe everything else is correct.
The best way I find of "fixing" this is to just disable the "Ip address dns check" option in the contact manager.
You could alternatively comment out the check in /scripts/maintenance, however this will be lost in updates.