This is a modification of the General_MachineDown KS. It is a useful MC Action for any ResponseTime Job. If one of your RT Jobs raises an Event it could add the information about the DNS, Network and Machine availability with that action KS. You will find that info in the Action Tab of the Event.
Example: Machine ALPHA is doing measurements against machine BETA. Once your RT measurement hits the threshold the action shows that the DNS name resolution is not working.