idk... It would be easier if you had the code for a CF server then you can just change a few things. Never coded a server so I'm not sure what would be the easiest way to do it, perhaps monitor the packets and try reconstruct a server on your own? I have no idea, but maybe there's an easier way.
EDIT: Maybe look to see how people make other kinds of private servers like WoW, Runescape, MapleStory, etc. That will proabably give u a good start.