A list of MAC addresses which are been belonging to the users computers can be entered into an Access Point and thus only those computers which are been entered will be allowed to access in it. When a computer makes a request for the MAC address it is then compared to that MAC address list which has been entered for the Access Point and the permission might be granted or denied. This is the best method for security but we suggest you to go for the smaller networks because there is a high rate of work is involved in entering each MAC address into every Access Point.