ICMP (Internet Control Message Protocol)

The Internet Control Message Protocol (ICMP) is a network protocol used to send error messages and operational information about network communication. For example, when a device cannot reach another over the internet, ICMP helps communicate that issue back to the sender. It plays a crucial role in diagnosing network problems, such as when using the "ping" command to check if a server is accessible. Essentially, ICMP helps devices on a network manage and troubleshoot their connections, ensuring smoother and more reliable communication.