Ninja's method is good, but a little easy to get into. Honestly, the best method of action would be to create a private server using a strange version number and then instate a lock. Once I get any knowledge of Visual Basic, I will create a small program that locks the server from any enterance. It is fairly easy with packet editing.

By the way, the program is legal. However, as Link said, distributing it is frowned upon. Few people have it, fortunately; do not go around asking for it, though.

~ Traft