Ping is a common and initial step for troubleshooting the problem in networking world. Ping tool tests TCP/IP network connectivity. It sends ICMP echo request messages to the host and expecting a reply. The destination host has to send a reply back to the sending host within a predetermined time. Ping sends a packet of 64 bytes (56=data+8=header). Echo request are send approximately after one second. It is also used to test the network interface card.
It gives us the following information.
- Remote host is alive or dead.
- Round trip time (time from sending to receive packet).
- Packet loss percentage.
(Note: ping tool test the reachability at the IP layer but the firewall and access list can be a blocker)