IRC


IRC is a text-based chat system for instant messaging. IRC is designed for group communication in discussion forums, called [|channels], but also allows one-on-one communication via private messages as well as chat and data transfer, including file sharing.
Internet Relay Chat is implemented as an application layer protocol to facilitate communication in the form of text. The chat process works on a client–server networking model. Users connect, using a clientwhich may be a web app, a standalone desktop program, or embedded into part of a larger programto an IRC server, which may be part of a larger IRC network. Examples of ways used to connect include the programs Mibbit, KiwiIRC, mIRC and the paid service IRCCloud.
IRC usage has been declining steadily since 2003, losing 60 percent of its users by 2012. In April 2011, the top 100 IRC networks served more than 200,000 users at a time.

History

IRC was created by Jarkko Oikarinen in August 1988 to replace a program called MUT on a BBS called OuluBox at the University of Oulu in Finland, where he was working at the Department of Computer Science. Jarkko intended to extend the BBS software he administered, to allow news in the Usenet style, real time discussions and similar BBS features. The first part he implemented was the chat part, which he did with borrowed parts written by his friends Jyrki Kuoppala and Jukka Pihl. The first IRC network was running on a single server named tolsun.oulu.fi. Oikarinen found inspiration in a chat system known as Bitnet Relay, which operated on the BITNET.
Jyrki Kuoppala pushed Oikarinen to ask Oulu University to free the IRC code so that it also could be run outside of Oulu, and after they finally got it released, Jyrki Kuoppala immediately installed another server. This was the first "IRC network". Oikarinen got some friends at the Helsinki University of Technology and Tampere University of Technology to start running IRC servers when his number of users increased and other universities soon followed. At this time Oikarinen realized that the rest of the BBS features probably would not fit in his program.
Oikarinen contacted people at the University of Denver and Oregon State University. They had their own IRC network running and wanted to connect to the Finnish network. They had obtained the program from one of Oikarinen's friends, Vijay Subramaniam—the first non-Finnish person to use IRC. IRC then grew larger and got used on the entire Finnish national network—FUNET—and then connected to Nordunet, the Scandinavian branch of the Internet. In November 1988, IRC had spread across the Internet and in the middle of 1989, there were some 40 servers worldwide.

EFnet

In August 1990, the first major disagreement took place in the IRC world. The "A-net" included a server named eris.berkeley.edu. It was all open, required no passwords and had no limit on the number of connects. As Greg "wumpus" Lindahl explains: "it had a wildcard server line, so people were hooking up servers and nick-colliding everyone". The "Eris Free Network", EFnet, made the eris machine the first to be Q-lined from IRC. In wumpus' words again: "Eris refused to remove that line, so I formed EFnet. It wasn't much of a fight; I got all the hubs to join, and almost everyone else got carried along." A-net was formed with the eris servers, while EFnet was formed with the non-eris servers. History showed most servers and users went with EFnet. Once A-net disbanded, the name EFnet became meaningless, and once again it was the one and only IRC network.
Around that time IRC was used to report on the 1991 Soviet coup d'état attempt throughout a media blackout. It was previously used in a similar fashion during the Gulf War. Chat logs of these and other events are kept in the ibiblio archive.

Undernet fork

Another fork effort, the first that made a lasting difference, was initiated by "Wildthang" in the United States in October 1992.. It was meant to be just a test network to develop bots on but it quickly grew to a network "for friends and their friends". In Europe and Canada a separate new network was being worked on and in December the French servers connected to the Canadian ones, and by the end of the month, the French and Canadian network was connected to the US one, forming the network that later came to be called "The Undernet".
The "undernetters" wanted to take ircd further in an attempt to make it use less bandwidth and to try to sort out the channel chaos that EFnet started to suffer from. For the latter purpose, the Undernet implemented timestamps, new routing and offered the CService—a program that allowed users to register channels and then attempted to protect them from troublemakers. The first server list presented, from 15 February 1993, includes servers from the U.S., Canada, France, Croatia and Japan. On 15 August, the new user count record was set to 57 users.
In May 1993, RFC 1459 was published and details a simple protocol for client/server operation, channels, one-to-one and one-to-many conversations. A significant number of extensions like CTCP, colors and formats are not included in the protocol specifications, nor is character encoding, which led various implementations of servers and clients to diverge. Software implementation varied significantly from one network to the other, each network implementing their own policies and standards in their own code bases.

DALnet fork

During the summer of 1994, the Undernet was itself forked. The new network was called DALnet, formed for better user service and more user and channel protections. One of the more significant changes in DALnet was use of longer nicknames. DALnet ircd modifications were made by Alexei "Lefler" Kosut. DALnet was thus based on the Undernet ircd server, although the DALnet pioneers were EFnet abandoners. According to James Ng, the initial DALnet people were "ops in #StarTrek sick from the constant splits/lags/takeovers/etc".
DALnet quickly offered global WallOps, longer nicknames, Q:Lined nicknames, global K:Lines, IRCop only communications: GlobOps, +H mode showing that an IRCop is a "helpop" etc. Much of DALnet's new functions were written in early 1995 by Brian "Morpher" Smith and allow users to own nicknames, control channels, send memos, and more.

IRCnet fork

In July 1996, after months of flame wars and discussions on the mailing list, there was yet another split due to disagreement in how the development of the ircd should evolve. Most notably, the "European" side that later named itself IRCnet argued for nick and channel delays whereas the EFnet side argued for timestamps. There were also disagreements about policies: the European side had started to establish a set of rules directing what IRCops could and could not do, a point of view opposed by the US side.
Most of the IRCnet servers were in Europe, while most of the EFnet servers were in the US. This event is also known as "The Great Split" in many IRC societies. EFnet has since grown and passed the number of users it had then. In the autumn of the year 2000, EFnet had some 50,000 users and IRCnet 70,000.

Modern IRC

IRC has changed much over its life on the Internet. New server software has added a multitude of new features.
  • Services: Network-operated bots to facilitate registration of nicknames and channels, sending messages for offline users and network operator functions.
  • Extra modes: While the original IRC system used a set of standard user and channel modes, new servers add many new modes for features such as removing color codes from text, or obscuring a user's hostmask to protect from denial-of-service attacks.
  • Proxy detection: Most modern servers support detection of users attempting to connect through an insecure proxy server, which can then be denied a connection. This proxy detection software is used by several networks, although that real time list of proxies is defunct since early 2006.
  • Additional commands: New commands can be such things as shorthand commands to issue commands to Services, to network-operator-only commands to manipulate a user's hostmask.
  • Encryption: For the client-to-server leg of the connection TLS might be used. For client-to-client communication, SDCC can be used.
  • Connection protocol: IRC can be connected to via both IPv4 and IPv6
, a new standardization effort is under way under a working group called IRCv3, which focuses on more advanced client features such as instant notifications, better history support and improved security., no major IRC networks have fully adopted the proposed standard.
there are 481 different IRC networks known to be operating, of which the open source Libera Chat, founded in May 2021, has the most users, with 20,374 channels on 26 servers; between them, the top 100 IRC networks share over 100 thousand channels operating on about one thousand servers.
After its golden era during the 1990s and early 2000s, IRC has seen a significant decline, losing around 60% of users between 2003 and 2012, with users moving to social media platforms such as Facebook or Twitter, but also to open platforms such as XMPP which was developed in 1999. Certain networks such as Freenode have not followed the overall trend and have more than quadrupled in size during the same period. However, Freenode, which in 2016 had around 90,000 users, has since declined to about 9,300 users.
The largest IRC networks have traditionally been grouped as the "Big Four"—a designation for networks that top the statistics. The Big Four networks change periodically, but due to the community nature of IRC there are a large number of other networks for users to choose from.
Historically the "Big Four" were:
  • EFnet
  • IRCnet
  • Undernet
  • DALnet
IRC reached 6 million simultaneous users in 2001 and 10 million users in 2004–2005, dropping to around 350k in 2021.
As of December 2025, the top 5 IRC networks have total participation of around 88,000 users per day, with remaining IRC networks having less than 10,000 users per day each. There are about 35 networks with at least 1,000 users per day.