Direct Client-to-Client (DCC) is a protocol used by many Internet Relay Chat (IRC) clients. Whereas users of an IRC network normally have their messages to each other or to a channel relayed through the network they're connected to, DCC allows them to connect directly to another user. This is most commonly used to send files back and forth, but may also be used to chat more quickly or more securely with the other user.
DCC connections can be initiated in two different ways:
The most common way is to use CTCP to initiate a DCC session. The CTCP is sent from one user, over the IRC network, to another user.
Another way to initiate a DCC session is for the client to connect directly to the DCC server. Using this method, no traffic will go across the IRC network (the parties involved doesn't even need to be connected to an IRC network in order to DCC).
The most common services provided by DCC includes:
CHAT: Will enable users to chat to eachother over a DCC connection. The traffic will go directly between the user and server, and not over the IRC network.
SEND: Lets users share files between eachother.
FSERVE: The DCC fserve lets a user browse, read and download files located on a DCC server. The interface has some similarities to a text-based FTP-client.
A description of the DCC protocol(note: Most IRC-clients and networks have implemented extentions to the DCC protocol. The DCC commonly used today have evolved quite a bit from what this document describes.)
See DCC for a list of other things this abbreviation is used for.
