The Internet Control Message Protocol (ICMP) is used by Internet nodes and routes to signal networking conditions, as well as for network diagnostics.

The RFC for ICMP is stored by the Internet Engineering Task Force (IETF).

For information on ICMP, see RFC 792: Internet Control Message Protocol DARPA Internet Program Protocol Specification.

For Microsoft licensing information, see Published Protocols and Royalty-Free License on Microsoft Developer Network (MSDN).