I have a 2003 Exchange Server SP2 that was looking to to an old DC for DNS. I demoted and retired the old DC and pointed the Exchange server to the new DNS servers. The Exchange server is still looking to the old non-existant DNS server as the default DNS server and it is verified when I use nslookup. I have edited the static IP settings in the network configuration and verified that there is no reference to the old DNS server with IPCONFIG/ALL. Even though it is a static connection, I have tried an ipconfig/registerdns and it did not change the default dns server. This is a production Exchange server. I am able to operate for now with static entries to the hosts file. I have already tried rebooting the machine.
Old DNS server x.x.x.5
New DNS servers x.x.x.8, x.x.x.13
DNS Servers . . . . . . . . . . . : x.x.x.8
*** Can't find server name for address x.x.x.5: Non-existent domain
Default Server: UnKnown