DNS is vital for Active Directory to function. If you want to use RIS, you must have DNS setup and properly configured. DNS is configured basically the same as it was in Windows 2000. The zones are a little different though. Instead of having Active Directory Integrated, Primary and Secondary zones, you now have a third type called a stub zone along with Primary and Secondary zones. Stub zones and Primary zones can be stored in Active Directory, while Secondary zones still say on the local machine. Stub Zones keep track of which DNS Servers are authoritative for the organization. They directly contact the root DNS Server for you organization to determine which Servers are authoritative for which domain. How is this helpful? If you were to delegate a DNS zone (Subdomain) to another server, a Stub server would know which servers were authoritative for all zones in the DNS namespace without having to query the Primary DNS server that is responsible for the parent zone.
are also Conditional forwarding zones in the new version of DNS.
This allows an administrator to specify different servers to query
for different record types.
For example, if you had an internal DNS server for nwtraders.msft
that you wanted all of you clients to access for name resolution to the
internal network; and you also had a different DNS server to resolve name
queries that go anywhere else, you can set up a Conditional forwarder that
all of the clients are configured to access in their TCP/IP properties for
DNS queries and that server would query the different servers for either
nwtraders.msft or internet name requests.