ICMP - Internet Control Message Protocol
ICMP is short for Internet Control Message Protocol. It is an extension to the Internet Protocol (IP) defined by RFC 792. ICMP supports packets containing error, control, and informational messages. It is an error reporting protocol and is used by routers, hosts and network devices to generate error messages when there are problems delivering IP packets.
ICMP is Defined by RFC 792
RFC 792 defins the goals and specifications for ICMP. ICMP, uses the basic support of IP , however it is actually an integral part of IP, and must be implemented by every IP module. As defined by RFC 792;
"ICMP messages are sent in several situations: for example, when a datagram cannot reach its destination, when the gateway does not have the buffering capacity to forward a datagram, and when the gateway can direct the host to send traffic on a shorter route. The Internet Protocol is not designed to be absolutely reliable. The purpose of these control messages is to provide feedback about problems in the communication environment." [source]
The Internet Control Message Protocol is used by routers, devices or hosts to communicate error information to other routers, devices, or hosts. An ICMP message contains TYPE, CODE and CHECKSUM fields. These fields identify the ICMP message, provide additional information about Type and provide a method for determining the integrity of the message.
The PING command, for example, uses ICMP to test an Internet connection.
Stay up to date on the latest developments in Internet terminology with a free weekly newsletter from Webopedia. Join to subscribe now.
From cute electronic toys to VR gaming, here are 5 hot gifts to give to your special tech enthusiast this holiday season. Read More »What's Hot in Tech: AI Tops the List
Like everything in technology, AI touches on so many other trends, like self-driving cars and automation, and Big Data and the Internet of Things... Read More »DevOp's Role in Application Security
As organizations rush to release new applications, security appears to be getting short shrift. DevSecOps is a new approach that holds promise. Read More »
Java is a high-level programming language. This guide describes the basics of Java, providing an overview of syntax, variables, data types and... Read More »Java Basics, Part 2
This second Study Guide describes the basics of Java, providing an overview of operators, modifiers and control Structures. Read More »The 7 Layers of the OSI Model
The Open System Interconnection (OSI) model defines a networking framework to implement protocols in seven layers. Use this handy guide to compare... Read More »