take this from on IT-NS, your NIC card ( Network Interface Card ) has a specific mac address. Meaning you can take the NIC card from one computer and put it in another and you will still have the same mac address.
And another thing your mac address of your computer is NEVER seen by the outside world. The router/default gateway's mac address is what is seen.
to me it makes for sence to ban off IP and the ports that are used.