Banning IP ranges from joining your server.

I am creating a server system and so far things are working very well. I have however been concerned about people trying to change their IPs so they can evade an IP ban system I am trying to create. I have thought about not only banning the user's IP, but banning their router so that any computer connected to it will be unable to join the server. How can I ban their router?

 

Authentication is the most common tactie to stop this. However, I have to disagree somewhat with @jackt_unity.
Authentication for this purpose (ignore the data collection part), can be broken down to some form of work that is needed to prove you are different to someone else. An example can be email verification, steam account verification etc. Just generating a UUID locally is not helping. But collecting emails and passwords is not something one should do themselves, thus services like Playfab exists. But the best option is to use your distribution platform to make it as easy as possible for the user. A great example is Steam, their SDK can be used for authentication. More advanced techniques include device fingerprinting etc, but it's generally left as it requires a lot of development in comparison to the benefits it will give you. One form of identity that actually requires work is Teamspeak3's "Identity Security Level" concept. Really interesting that does computation to "strengthen" an identity.


Here is a good place to start reading: https://en.wikipedia.org/wiki/Hashcash