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The TCP/IP Guide  9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)       9  TCP/IP Key Applications and Application Protocols            9  TCP/IP Interactive and Remote Application Protocols

Other Berkeley Remote ("r") Commands (rcp, ruptime, rwho) 1 2 3 TCP/IP Administration and Troubleshooting Utilities and Protocols

Individual Messaging

IRC also supports one-to-one communication, which can be used for private conversation. To use this method, all a user needs is the nickname of another user to whom he or she wants to talk; he or she uses a special command to send messages directly to that user, who can respond in kind. This is not a secure form of communication, since the messages are not encrypted, and they pass through servers where they could be monitored. However, there is so much traffic on a typical IRC network that any given message is unlikely to be monitored, so there is not much concern (unless you work for the CIA or just developed a cure for the common cold or something. J)

The IRC protocol defines a rich command set that allows users to perform essential functions, such as joining or leaving a channel, changing nicknames, changing servers, setting operating modes for channels and so forth. The exact command set and features available depends both on the specific software used for the user’s IRC client, and the features available on the IRC network itself, not all of which run the same version of the protocol.

IRC became very popular in the early 1990s because of the powerful way that it allows users from anywhere on the Internet to meet and share information dynamically. Not only does it act like a text-based “telephone”, it allows users across the globe to communicate without the expense of a long-distance call.

One of the most important characteristics of IRC is its open-ended nature: it gives every person the freedom to communicate in whatever way he or she considers best. For example, every IRC channel has an owner, who has certain rights related to how the channel is used, including the ability to decide who should be allowed in the channel and who not. This may seem autocratic, but IRC lets anyone start a new channel instantly and become that channel’s owner, without the need for prior registration or authorization. This means that if you don’t like how a particular channel is run, you can start your own with a minimum of fuss; you are not forced to adhere to anyone’s rules, other than the rules set forth for the server (which are usually just intended to prevent abuse.)

This same principle extends to the IRC networks themselves as well—there isn’t just one single IRC network, there are dozens of different ones. Some are large, well-established networks that may have over 100 servers and thousands of users, while others are smaller and devoted to specific areas of interest or geographical regions. Anyone can set up their own IRC network if they have the hardware and software, and some organizations have in fact set up private, dedicated IRC servers for their own use.

IRC is considered by many to be the most important “ancestor” of the related interactive applications collectively known as instant messaging. These services are offered by several organizations, including America Online (AOL), Yahoo! and Microsoft’s MSN. The idea behind them is very similar to that of IRC; each allows a message sent by one user to be displayed immediately to another, though most are focused primarily on user-to-user messages rather than groups. Instant messaging has in fact surpassed IRC in overall use, perhaps due to the large subscriber base of services like AOL. However, IRC is still widely used by thousands of enthusiasts on a daily basis for both entertainment and business purposes.

Other Berkeley Remote ("r") Commands (rcp, ruptime, rwho) 1 2 3 TCP/IP Administration and Troubleshooting Utilities and Protocols