ICMP

The ICMP (Internet Control Message Protocol) can be used to determine the status of participants in a network making it possible to send test data to a client and receiving an answer. In doing so, ICMP provides a simple way to determine the availability of another network participant.

Typically, ICMP is a good way to initially test for problems in a network by finding out if the "other side" is generally available. On most operating systems, the simple command "ping" can be employed to use ICMP. Most ICMP clients provide important statistics, such as the "ping," which shows the responsiveness of a network between two participants and indicates the time necessary for a request to be answered.