| Communication protocol | |
 A general header for ICMPv4 | |
| Purpose | Auxiliary protocol for IPv4[1]: 52 |
|---|---|
| Developer(s) | DARPA |
| Introduction | 1981 |
| OSI layer | Network layer |
| RFC(s) | RFC 792 |
The Internet Control Message Protocol (ICMP) is a supporting protocol[2] 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 IP address. For example, an error is indicated when a requested service is not available or that a host or router could not be reached.[3] ICMP differs from transport protocols such as TCP and UDP 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 ping and traceroute).
A separate Internet Control Message Protocol (called ICMPv6) is used with IPv6.[4]
| Internet protocol suite |
|---|
| Application layer |
| Transport layer |
| Internet layer |
| Link layer |
- ^ F. Baker, ed. (June 1995). Requirements for IP Version 4 Routers. Network Working Group. doi:10.17487/RFC1812. RFC 1812. Proposed Standard. Obsoletes RFC 1716 and 1009. Updated by RFC 2644 and 6633.
- ^ J. Postel (September 1981). INTERNET CONTROL MESSAGE PROTOCOL - DARPA INTERNET PROGRAM PROTOCOL SPECIFICATION. Network Working Group. doi:10.17487/RFC0792. STD 5. RFC 792. Internet Standard 5. Updates RFC 760, 777, IENs 109, 128. Updated by RFC 950, 4884, 6633 and 6918.
- ^ Forouzan, Behrouz A. (2007). Data Communications And Networking (Fourth ed.). Boston: McGraw-Hill. pp. 621–630. ISBN 978-0-07-296775-3.
- ^ A. Conta; S. Deering (March 2006). M. Gupta (ed.). Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification. Network Working Group. doi:10.17487/RFC4443. STD 89. RFC 4443. Internet Standard 89. Obsoletes RFC 2463. Updates RFC 2780. Updated by RFC 4884.