What is the function of ICMP in networking?

The Internet Control Message Protocol (ICMP) is primarily used in networking to send error messages and operational information. This includes notifications about issues such as unavailable hosts, routing failures, and packet loss, which help in diagnosing network problems. For instance, when a router cannot forward a packet due to a lack of a proper route, it can send an ICMP message back to the sender, indicating the problem.

ICMP plays a crucial role in network management by providing feedback on the status of network communication. This helps network administrators troubleshoot and are aware of the network's health and issues. It is a vital protocol for maintaining efficient and reliable network operations. The other options refer to different functions in networking; managing connections, data encryption, and DNS functionality are handled by different protocols and systems.