You need to configure a Forwarding List for your DNS server object,
which tells it what DNS servers to query when it can't resolve a
client's request. And you need to open your firewall to allow DNS
queries to pass from your DNS server to the outside. Finally, you can

restrict what URLs are resolved by entering their info into your DNS servers No Forward List -- e.g., entering in the list
would prevent all urls ending with from being resolved.
NSC Volunteer SysOp