A tcm can be viewed as an extention of the irc server itself, it offloads some of the administrative work of the oper unto another process. Akin to using an unix pipeline, not building everything into one program, but rather using other processes as building blocks to a better whole.
tcm monitors all connections to the server, and checks for too many connections from one user@host in too quick a time. It can be compiled to, notify opers of the possible clones or automatically k-line the possible clones.
A tcm on a server which supports it (currently ircd-hybrid) will monitor connections in IP (/24) blocks, looking for clones from so-called virtual hosts. Presently, tcm will just notify opers of potential clones and does not take any automatic action.
A tcm also monitors for excessive links request, and will either auto kill or auto kline as configured at compile time
tcm can be used by remote opers, either those already in the conf file for the server, or those you add to userlist.cf of tcm
tcm can be remotely linked to other tcm's, allowing remote k-lines or just remote communication line.
Nick flooding is also detected and can trigger either a kill or a k-line or just an oper warning.
Bot sign on notices are also noted by tcm and it can be compiled to auto-kline eggdrops etc. run by stupid bot runners.
stats p requests on the server are also noted by the tcm and result in a listing of active tcm opers.
Privmsg's to the tcm can be optionally relayed to opers on the tcm
tcm was originally written by Hendrix, an oper at irc.texas.net. It stood for "texas connection monitor". Various versions of tcm kicked around the net for a while, before I got a hold of a copy for use on irc.mo.net...When Shadowfax added +n nick following code to irc.mo.net I started adding code to detect nick flooders to tcm. Poor shadowfax never beat me at adding k-lines for clones, so one day I added code to suggest klines to use, which could be cut and pasted in a hurry. Phisher took it the next step, which was to automatically k-line cloners. Toast contributed some code, which has been folded in. This all became a part of tcm-dianora. tcm is a long way from what originally was coded by hendrix, there are still some remnants left, but not too many now.
Currently, tcm-dianora is about to become tcm-hybrid, with more open access to a few other coders. I refer to tcm as just plain tcm in these documents for that reason.
Now is the day! As of May, 2000, tcm-dianora is now tcm-hybrid! REJOICE!