The purpose of ping is to measure the round-trip time (RTT) for messages sent from a source host to a destination host that are then echoed back to the source. It uses internet Control Message Protocol (ICMP), sending ICMP Echo Request packets to the destination host and waiting for an ICMP Echo Reply.
The first item reported is the size of the packet received. The default size is 56 bytes, but an ICMP ECHO_REQUEST packet contains an additional 8 bytes of an ICMP header followed by an arbitrary amount of data. Thus, the size reported is 64 bytes. Next is the destination IP address. By default, ping displays the IP address to which the hostname resolves rather than the hostname.
The icmp_seq field reveals the ordering of the ICMP packets. ...
