Since VNC connections travel over the same IP networks that any other
sort of Internet connection does, it's a good idea to verify that the
network connection between you Viewer and Server is working. That's
what the "ping" command is good for. In Windows, open up a DOS Command
line and type:

      ping [ip.adddress.of.Server]  (eg, "ping 192.168.0.10")

...and see if it works correctly. If you can't get a ping connection
to work, it's unlikely that you'll be able to get a VNC connection to
work.