Internet Control Message Protocol (ICMP) is a supportive protocol used primarily by network devices to communicate updates or error information to other devices. When troubleshooting network issues in a Linux environment, ICMP forms a crucial aspect. It can be utilized to send error messages indicating, for example, that a requested service is not available or that a host or router could not be reached. ICMP can also be used to relay query messages.
In Linux systems, common command-line tools related to ICMP include ping and traceroute, both used to diagnose the state of the network and often part of troubleshooting efforts.
# Use of ICMP via the ping command to send an echo request to a specific host
ping www.google.com
This simple yet effective tool should not be missed out in any Linux network troubleshooting arsenal.