Testing the Network Connection with Ping
Ping is a tool that helps to verify IP-level connectivity. It checks whether a specific IP address is accessible by sending a packet to the address and waiting for a response. Ping can also be used to determine the numeric IP address for a given domain name.
To check that another computer on a network is reachable:
Open a Command Prompt window and type:
ping <destination machine's domain name or IP address>
If the destination host machine does not respond, it might be offline or there may be a network problem along the way. If it does respond, the problem might have been a transient one (so you can reconnect now), or the server application you were connected to might have terminated (so you might not be able to connect again). If the result is "unknown host", the destination machine is not recognized by the source machine.
Ping uses name resolution to resolve a computer name to an IP address. Therefore, if pinging by IP address succeeds, but fails by name, the problem lies in host name resolution and not network connectivity.