<P> The ping utility was written by Mike Muuss in December 1983 as a tool to troubleshoot problems in an IP network . He was inspired by a remark by David Mills on using ICMP echo packets for IP network diagnosis and measurements . The author named it after the sound that sonar makes, since its methodology is analogous to sonar's echo location . The first released version was public domain software, all following versions were licensed under the BSD license . </P> <P> RFC 1122 prescribes that any host must process ICMP echo requests and issue echo replies in return . However, as a security consideration, this is often disabled . </P> <P> The following is the output of running ping on Linux for sending five probes to the target host www.example.com: </P> <P> The output lists each probe message and the results obtained . Finally it lists the statistics of the entire test . In this example, the shortest round trip time was 97.427 ms, the average was 97.453 ms, and the maximum value was 97.483 ms . The measurement had a standard deviation of 0.198 ms . </P>

What is in the payload of an icmp echo packet