This is probably one of the more weird problems I've seen. We have XP clients in our district offices who are configured through the local router via DHCP. That DHCP server is assigning them our main DNS server 192.168.1.221 and then a local ISP DNS server. Randomly our clients DNS will stop working on their machines. When doing an IPCONFIG /ALL, all the settings are correct. If we statically assign the DNS servers in the Network Configuration options in the client control panel DNS works fine. Then if I switch it back to DHCP, it works for a random period of time and goes back to this same problem.
While the machines are experiencing this problem, I can run an nslookup to the DNS server by name and it resolves correctly. However, if I try to ping the same DNS name I just ran NSLOOKUP on, it says "Ping request could not find host <computername>. Please check the name and try again." We are not getting any errors in the DNS event viewer since 11/12 and the last error is:
The DNS server has encountered a critical error from the Active Directory. Check that the Active Directory is functioning properly. The extended error debug information (which may be empty) is "". The event data contains the error.
This is very frustrating as I'm not 100% sure that it's really a DNS issue or network configuration problem. Any help would be very helpful.