ICMP, Internet Control Message Protocol, is a networking protocol. Its purpose is to pass on error messages (such as “unreachable host”) and informational messages (such as ping requests and responses), rather than application data.
- RFC 792 — Internet Control Message Protocol (September 1981)
Similar to the Internet Protocol (which has a number, RFC 791, exactly one less than this one), the original document refers to just “ICMP” rather than “ICMPv4”. ICMPv6, described below, follows different rules.
Additions and Deprecations
- RFC 4884 — Extended ICMP to Support Multi-Part Messages (April 2007)
- RFC 6633 — Deprecation of ICMP Source Quench Messages (May 2012)
- RFC 6918 — Formally Deprecating Some ICMPv4 Message Types (April 2013)
Current ICMPv6 RFC
- RFC 4443 — Internet Control Message Protocol for the Internet Protocol Version 6 Specification (March 2006)
There are two older versions of the specification:
- RFC 1885 — Internet Control Message Protocol for the Internet Protocol Version 6 Specification (December 1995)
- RFC 2463 — Internet Control Message Protocol for the Internet Protocol Version 6 Specification (December 1998)
ICMP Parameter Numbers
IANA also maintains the lists of parameter numbers for ICMPv4 and parameter numbers for ICMPv6.