IRCD

IRCd, short for Internet Relay Chat daemon, is a server program that implements the IRC protocol and forms the backbone of an IRC network. It handles client connections, channel management, user permissions, and the distribution of messages across servers in the network.

An IRC network consists of multiple IRCD instances linked by server-to-server protocols. Each server handles local clients and channels, while information about users, channels, and messages is propagated to other servers to maintain a coherent network state.

Core responsibilities of an IRCD include managing nicknames, creating and moderating channels, enforcing user and channel modes, and applying bans. Many networks support services such as NickServ and ChanServ to register identities and channels, enabling persistent identities and automatic access control.

IRCd implementations vary, with common open‑source options including UnrealIRCd, InspIRCd, ircd-hybrid, Bahamut, Charybdis, and ratbox. They differ in configuration syntax, feature sets, scalability, and licensing, which can range from BSD to GPL licenses. Networks may also adopt extensions and anti‑abuse features to enhance security and reliability.

The IRC protocol originated in 1988 with Jarkko Oikarinen, and IRCd software has evolved to support TLS, SASL authentication, IRCv3 extensions, and advanced moderation tools. Despite these evolutions, IRCd remains focused on providing a robust and extensible server platform for multi‑server IRC networks.

IRCd software is typically run on Unix-like systems, though some implementations are cross‑platform. Large networks rely on multiple servers to provide redundancy, load distribution, and geographic reach, ensuring continuous access for clients around the world.