Linux ping Command
The ping tool is used to test the network connection between your system and some remote host. ping uses the ICMP echo message, which tests the connection from the local IP layer to the remote IP layer.
$ ping dog.example.org
$ ping 192.168.0.9
The two(2) format above are both valid, the first if a DNS is setup then it would map the host name to it's proper IP address. The 2nd format is the most common and it accepts the IP address directly. A high packet loss, packets arriving out of sequence, or high round-trip times can indicate a congested network or a bad connection.