In this series of three articles, of which this one is the first, we are going to discuss what an IRC network is, how it works and the underlying protocol. IRC gives us a lot more choices and is much more complicated than the regular chat applications, as you will see.
Because a network can contain many thousands of clients, it stands to reason that there must be someone to moderate or make sure that everything runs smoothly. That is exactly what an operator does. The operators, essentially a special group of clients, are allowed to do general maintenance on a network.
Operators have powers to connect and disconnect servers as needed "to prevent long-term use of bad network routing." They also have the power to remove a user from the network by force by disconnecting a client from the server. It is debatable whether clients should have this kind of power, but it is definitely needed.
Channels
A channel is a named group of clients that converse in the same channel. A channel is created by the first client that joins it and closes down when the last client leaves. Channel names must start with a "&" or "#" symbol with up to 200 characters. The only restriction on a channel name is that it may not contain any spaces (' '), a control G (^G or ASCII 7), or a comma (',' which is used as a list item separator by the protocol).
There are two types of channels allowed by this protocol. One is a distributed channel which is known to all the servers that are connected to the network. The other type of channel is limited to one server, and only clients on the server where it exists may join. These channels are distinguished by a leading '&' character.
On top of these two types, there are the various channel modes available to alter the characteristics of individual channels. The RFC provides more information on the different MODES. To create or to take part in an existing channel you JOIN the channel. By creating a new channel you automatically become the channel operator.
Whether your request to JOIN a particular channel is accepted will depend on the mode of the channel. For example, if you try to join a channel where the mode dictates a limit to the number of users that can join, and you try to join when that limit has been reached, then your request will be refused. Similarly if you try to join a channel that is "invitation only," your request will be rejected unless you are invited. The protocol also states that a user may join up to ten channels simultaneously.
Delphi-Kylix 
A Brief Look at Indy
