How do I use the MAC address as the identification system of

When a player enters the game server or connect to the game server, I want to make sure that the server itself is able to recognize it according to the MAC address of the computer. In this way, if the player tries to access the game from another computer, it can not. If the player always accessed from the same computer, the server connection will not have to type any code.

I realize that I have given little information. I'm sorry.

Here is the information that were missing:

The game will run on HTML5, browser entirely saved on a server of my property.

The player will not have to download anything on your computer.

All data and developments of the player are saved on the server.

After a first recording fictitious (name, character class), the player will be able to access the game every time, without entering a password of sorts.

I want to make sure that the server remembers Player, locating it in some way, perhaps with the MAC address