[SMX]

You can't ban on MAC addresses, well you can but only devices in your subnetwork.
The only MAC addresses you can see are the ones from devices directly connected to your server/device.

Quote:

Originally Posted by http://en.wikipedia.org/wiki/Media_Access_Control The MAC layer addressing mechanism is called physical address or MAC address. This is a unique serial number assigned to each network adapter, making it possible to deliver data packets to a destination within a subnetwork, i.e. a physical network consisting of one or several network segments interconnected by repeaters, hubs, bridges and switches, but not by IP routers. An IP router may interconnect several subnets.