The ping command tests the accessibility of a specific IP address. The ping command sends an ICMP (Internet Control Message Protocol) echo request packet to the destination address and then waits for an echo reply packet to return from that host. ICMP is an Internet protocol that is used to verify communications. It measures the time that elapses between when the request packet is sent and the response packet is received. The ping command output indicates whether the reply was received successfully and displays the round-trip time for the transmissions.