MAC filtering is a way to enforce security on a Wi-Fi network at a deeper level than WEP encryption.
Each device on a Wi-Fi network has a MAC (Media Access Control) address, or unique identification number baked into the hardware. (See Appendix A, “Wireless Standards,” for more information about the MAC layer.)
The idea behind MAC filtering is to tell the Wi-Fi access point that it can only communicate with the devices on your network that are explicitly identified to it by their MAC address. You go into the access point/router's administrative application, and say, “Use these MAC addresses and no others!”
MAC filtering is a ...