The Quantum 1873 client will still use XTrap, if it's available in the folder. And if it is, it will quit instantly, as it fails the update check. (some kind of hash algo for the exe in XTrap). Other clients may be similarly linked to GameGuard or nProtect... which are not included in the Korean releases.
The urls you mention are for Clan and SoD information... They are not very important until you have your Sod ranking and Clan hosting up... Likewise sql.dll and clan.dll in the server folder is only for Clan and SoD.
The IP hard coded at the end of Quantums client replaces the one read from the registry entry for "Server1", you put your servers IP in that location, and then you don't have to mess with all the other registry fixes, ptreg.rgx, lData.bmp etc nonsense.
It also stops noobs who don't know what a hex editor is connecting to someone elses server with your client executable, which is a nightmare to tech-support them through when it happens.
There are details on how to create an account manually in SQL Management Studio... you can take that to any server side scripting you like. But there is a reasonably good example in ASP by Quantumfusion floating around many threads on this form.
I say reasonably good, because while it works well, I have some issues with the coding style.
For example:-
It is VB Script, but it doesn't say that it is, or that it isn't Java Script or anything... which can't be good for the poor server IMHO.
It uses "Alert" to say, "Yes, you are registered" or "No, that name is taken" etc. But alerts only really work well on IE, and many popup blockers block alerts too. They are kind of annoying.
But it's a great reference because it shows just exactly what needs to be done.