Administrators can easily identify, monitor and control forwarding queries. Determines whether server attempts to clean up responses to avoid cache pollution. Limits number of A records put in answer to query. Administrators can reduce logging to avoid DoS because of log entries. Administrators can log to the packet level if needed.
Administrators can control a specific servers behavior.
Block an internal development DNS server and make the client fall back to a secondary server. Don't forget to stop and start the service for the changes to be in effect. I'm in the process of looking under the DNS hood of Windows 2000. With Active Directory and DDNS, this is appears to be only the tip of the iceberg. And I'm waiting for the results of the next W2K service pack rollout to begin any serious work in this area.