Question: Is MAC address filtering really useful?
As you know MAC Address filtering can be configured on wireless router or access point to filter and allow only wireless adapters with MAC address in allowed list to join wireless network. If your wireless adapter’s MAC address is not in the allowed list, it cannot join wireless network with no connectivity, access local only or other network error.
This approach is useful if you deploy it on small home or office wireless network (I recommend it), but not so good for big network as it’s time consuming to maintain long MAC address allowed list. Furthermore this filtering can be overcome by experienced users with good networking knowledge or hackers, by using sniffing program to gather those MAC addresses that are allowed to join wireless network, and then configure the captured MAC address manually on his/her wireless adapter’s properties and join wireless network (we call it MAC address spoofing).