Internet Relay Chat

IRC (Internet Relay Chat) is a popular chat system based on a client-server protocol. Users are distinguished by nickname (nick) and are allowed to send each other messages, privately or via public chat rooms (channels). Each user can join more than one channel at a time.

The success of IRC networks is largely due to the flexibility of the protocol, its ability to handle thousands of simultaneously active users and channels.

Certain priviliged users, such as channel operators and server administrators, can censor or otherwise perform actions limit to the freedom of users:

• kick: expelling a user from a given channel
• ban: excluding users, identified by nickname or hostname, from a given channel
• K-line: preventing a class of users (identified by their hostname or IP number) from connecting to a given server.

IRC protocol is based on a centralized or semi-centralized network, with unencrypted connections: this means that the activity of end users can be supervised by the same owners of the servers composing the network.