See also: Chat Clients | Using IRC | Oldschool

Acronym: Internet Relay Chat

Also: blanket-term for “IRC-style” programs.

  1. Chat system
  2. Protocol for a chat system

1. A chat system using a semi-centralized network of servers that can be accessed by client programs. The protocol for IRC is open, and there are many client (and server) implementations. It is non-commercial, one of the oldest services on the Internet, and still very popular.

2. IRC protocol is a plaintext protocol, which means that it is fully possible to use IRC via telnet, although somewhat inconvenient for multiple conversations. It also means that it is possible to intercept and read the communication between client and server, and even hijack and inject the connection. This is unfortunate, as there has been quite a lot of takeover wars on various IRC Networks that are disruptive for other users.

Clients & Getting Started

  • For clients and a basic HOWTO, see Using IRC


Created by Jarkko Oikarinen (WiZ) in August 1988. It was first written to replace a program called MUT (MultiUser Talk) on a Bulletin Board System called OuluBox in Finland. Jarkko Oikarinen found inspiration in Bitnet Relay Chat which operated on the Bitnet network.

RFC 1459 describes the protocol used by the early IRC2; RFC 2810, RFC 2811, RFC 2812 and RFC 2813 describe one set of proposed IRC extensions: most IRC implementations consist of IRC2 with various add-ons and protocol extensions, resulting in incompatibilities preventing connection of servers running different software.

Today there are many IRC networks, the largest include Efnet, Undernet, IRCNet and Dalnet. They run various implementations of server software, but the protocol exposed to IRC users is very similar, and all IRC networks can be accessed by the same client software.

Based on a Wikipedia article licensed under the FDL.

Related Topics

TakeDown.NET -> “IRC