Intergrated active directory DNS windows 2003

When you have DNS integrated with active directory you can have more than 1 primary DNS, you don’t have a secondary DNS unless you have non-domain computers in your environment. When you set up TCPIP on the workstations how do you get fault tolerance in the DNS settings? You put a primary DNS server xxx.xxx.xxx.xxx, if you put in a secondary xxx.xxx.yyy.yyy you really don’t have a secondary DNS server. If you just put in the primary and the primary server crashes how do you take advantage of the other domain controlers that are running DNS