Quassel IRC is a program to connect to an IRC network. It has the unique ability to split the graphical component (quasselclient) from the part that handles the IRC connection (quasselcore). This means that you can have a remote core permanently connected to one or more IRC networks and attach a client from wherever you are without moving around any information or settings. However, Quassel can easily behave like any other client by combining them into one binary, which is referred to as "Quassel Mono".
Quassel IRC is a modern, cross-platform, distributed IRC client, meaning that one (or multiple) client(s) can attach to and detach from a central core -- much like the popular combination of screen and a text-based IRC client such as WeeChat, but graphical. In addition to this uniqe feature, we aim to bring a pleasurable, comfortable chatting experience to all major platforms (including Linux , Windows , and MacOS X as well as Qtopia-based cell phones and PDAs), making communication with your peers not only convenient, but also ubiquitous available.
In simpler terms, the "monolithic" client is a response to requests for a client that behaves like every other IRC client. The monolithic client (GUI) is what makes the connections to the IRC networks. In normal operation, the client (GUI) connnects to a core, it is completely incapable of connecting to anything else. The core recieves connections from clients, and makes connections to the IRC networks, it also handles logging (currently everything gets put in the database).
The license of this software is Free, you can free download and free use this irc client software.