 Internet protocol used for error messages in network operations | |
| Purpose | Auxiliary protocol for IPv41 |
|---|---|
| Developer | DARPA |
| Introduction | 1981 (1981) |
| OSI layer | Network layer |
| IP number | 1 |
| RFC | 792 |
The Internet Control Message Protocol (ICMP) is a supporting protocol2 in the Internet protocol suite. It is used by network devices, including routers, to send error messages and operational information indicating success or failure when communicating with another . For example, an error is indicated when a requested service is not available or that a or router could not be reached. ICMP differs from such as and in that it is not typically used to exchange data between systems, nor is it regularly employed by end-user network applications (with the exception of some diagnostic tools like and ).