title: identify a machine not by using IP
body: <p>Suppose I'm programming a game and I want the option of banning people from it after violating the terms. I can ban them per account, I can also ban their IP but it's not going to ban them from my game forever. They will just have to create a new account and change their IP.</p>
  
  <p>Is there something like a machine-ID that is unique for every machine in the world? If there is, is it possible to read it using a program language? Is it possible for the user to change this machine-ID? </p>