The Undernet is the third largest publicly monitored Internet Relay Chat (IRC) network, c.[clarification needed] 2022, with about 36 client servers serving 47,444 users in ~6000 channels at any given time.

[3] Undernet was established in October 1992 by Danny Mitchell, Donald Lambert, and Laurent Demally as an experimental network running a modified version of the EFnet irc2.7 IRCd software, created in an attempt to make it less bandwidth-consumptive and less chaotic, as netsplits and takeovers were starting to plague EFnet.

Again in 2001, it was threatened by automated heavy spamming of its users for potential commercial gain.

Undernet survived these periods relatively intact and its popularity continues to the present day.

It is notable as being the first network to utilize timestamping, originally made by Carlo Wood, in the IRC server protocol as a means to curb abuse.