You can verify that a database node or Unity server can find the Name Server by running nslookup from the command prompt:
nslookup [node_name|unity_server_name]
where the specified name is not the name of the node or Unity server from which you run the nslookup command.
The nslookup fails if the specified node or Unity is unable to find the Name Server.
The nslookup output verifies that the /etc/resolv.conf file is set up properly, for example:
domain esrootdom.esdev.tdat search esrootdom.esdev.tdat nameserver 141.200.3.8
where esrootdom.esdev.tdat is the Kerberos domain.