IRCd

An IRCd, short for Internet Relay Chat daemon, is server software that implements the IRC , enabling people to talk to each other via the Internet (exchanging textual messages in real time). It is distinct from an IRC bot that connects outbound to an IRC channel.

The server listens to connections from IRC clients on a set of TCP ports. When the server is part of an IRC network, it also keeps one or more established connections to other servers/daemons.

The term ircd originally referred to only one single piece of software, but it eventually became a generic reference to any implementation of an IRC daemon. However, the original version is still distributed under the same name, and this article discusses both uses.

The original IRCd was known as 'ircd', and was authored by Jarkko Oikarinen (WiZ on IRC) in 1988. He received help from a number of others, such as Markku Savela (msa on IRC), who helped with the 2.2+msa release, etc.

In its first incarnations, IRC did not have many features that are taken for granted today, such as named channels and channel operators. Channels were numbered – channel 4 and channel 57, for example – and the channel topic described the kind of conversation that took place in the channel. One holdover of this is that joining channel 0 causes a client to leave all the channels it is presently on: "CHANNEL 0" being the original command to leave the current channel.

The first major change to IRC, in version 2.5, was to add named channels – "+channels". "+channels" were later replaced with "#channels" in version 2.7, numeric channels were removed entirely and channel bans (mode +b) were implemented.

Around version 2.7, there was a small but notable dispute, which led to ircu – the Undernet fork of ircd.

irc2.8 added "&channels" (those that exist only on the current server, rather than the entire network) and "!channels" (those that are theoretically safe from suffering from the many ways that a user could exploit a channel by "riding a netsplit"), and is the baseline release from which nearly all current implementations are derived.

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