Checking the client's response from the server with 
  nsradmin -p nsrexec -s <nw_client>
is fine - you do not even need an output. If the client does not respond (if 
the prompt does not appear) then you already have a problem.

If it is intermittent, often restarting the client service solves the problem.

BTW - when we updated our clients from 7.5.x to 7.6.x there was the issue that 
the client service would not start.
The reason was an issue with update of the client's res files.
In this case, just delete/rename "....\nsr\res\nsrladb" and restart the service.

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