I have a Backup Domain Controller that cannot access computers by their computer name when their IP address is in a different range. However, the server can access any computer by the computer name where the IP address is in the same range. The computer can access any other computer if it accesses by the IP address. So the computer name is not mapping to the IP address when the IP address is not in the same range as the servers.
The server is running Windows NT 4.0 SP 6a