Configuring Conditional Forwarding

Another new feature added to Windows 2003 DNS server is conditional forwarding. Conditional forwarding forwards DNS queries to the DNS name server specified in the query. Both stub zones and conditional forwarding provide the ability to control routing DNS traffic on your network.

Windows 2000 Servers forward all requests to the same set of servers listed as forwarders. This can be inefficient because not all servers have information about the query. Conditional forwarding improves granularity with name-specific forwarding.

When do you use conditional forwarding instead of stub zones? Both allow a DNS server to respond to a query with a referral or forwarding to another DNS server. A conditional forwarder configures the DNS server to forward the query it receives to a DNS server listed in the header of the query. A stub zone keeps the DNS server hosting the parent zone aware of all authoritative servers for the child zone.