ICMP

Stands for “Internet Control Message Protocol.”

ICMP is an error-reporting protocol that helps diagnose issues with a TCP/IP network connection. It is a network-level protocol that assists within the motion of knowledge packets between networks, and it is a vital a part of the Internet Protocol (IP) suite. Network units like routers and switches ship ICMP error messages when an information packet can’t attain its vacation spot.

Transferring knowledge between two computer systems over the Internet requires a sequence of separate network connections alongside the way in which. Each knowledge packet strikes from network to network, forwarded to the following step by every network’s router. A sequence of packets despatched between the identical two computer systems could even take completely different routes and arrive out of order earlier than being reassembled at their vacation spot. If any device can’t efficiently ahead a packet to its next hop, it sends an ICMP error message back to the packet’s supply.

The ICMP protocol specifies a number of error sorts that assist establish a connectivity drawback. For instance, a Time Exceeded error implies that the info packet’s TTL expired earlier than it reached its vacation spot, whereas a Parameter Problem error signifies an issue with the info packet’s IP header. Some error sorts embody a subtype code that gives more element. The Destination Unreachable error, for instance, has 16 doable subtypes that every describe a special trigger. In most circumstances, software program on the origin pc resolves these errors mechanically by sending the info packet once more or attempting a special route, typically with out the person noticing. However, diagnostic instruments like Ping and Traceroute use ICMP messages that can assist you diagnose connectivity issues between your pc and a distant server.