Little bit old topic but can make explanation to others also.
1. You can't resolve internal IP (like 192.168.0.1) using external DNS.
If You have domain "mydomain.com" at IP address 185.11.32.40 and "
www.mydomain.com" at IP address 185.11.32.41 and "ns1.mydomain.com" at IP address 185.11.32.42 then it means, that ANYONE in the world will ask about one of those addresses will get assigned IP address in return.
Example:
ping
www.mydomain.com will result in pinging address 185.11.32.41
In this case, if You set "ovirt1.mydomain.com" at address 192.168.0.1 than ANYONE IN THE WORLD pinging addres "ovirt1.mydomain.com" will ping addres 192.168.0.1, but not Your's because address 192.168.0.1 exsists only in local networks. So if any person will ping that "ovirt.mydomain.com" will reach his own addres in local network (if it exists in his local network)
It is also dangerous because it reveals Your internal lan configuration to the world
2. If You have "mydomain.com" set in external DNS and the same domain You will set in Your internal Zentyal server/router
In this case ANY internal workstation/server will search subdomains on Your internal server. So if You have registered "
www.mydomain.com" on external DNS and "ovirt1.mydomain.com" on internal DNS than workstation asking "ovirt.mydomain.com" will get IP address, but asking "
www.mydomain.com" will get no rsult because it will not ask external DNS as internal DNS is master for him.
If You set external DNS as master, then You will not find "ovirt1.mydomain.com"
3. In local networks You can use LOCAL domain like "mylan.local" and in this case in internal network You can set "ovirt1.mylan.local". and start pinging like ping ovirt1
4. Set transparent DNS
All Your internal workstations/servers will treat Zentyal DNS as DNS cache. It reduces external DNS ask and does not reveal internal IP structure to the world (and foreign DNS owners). Do in Your DHCP delete external DNS addresses (like google's 8.8.8.8 ). Instead let Your Zentyal ask external DNS and send it to Your LAN.