The Media Access Control Address or MAC address is a unique address that is assigned to each device that is connected to a network. Most of the Wireless and Wi-Fi Routers have a special feature called wireless MAC filtering that lets you filter devices using their MAC addresses. MAC Addresses are assigned to each network card on the device and is used to determine the access of the device to the network.
MAC Filtering is a special security feature by which you can prevent any unwanted devices from connecting to your wireless network because, with the MAC Filtering feature, only those devices will be able to join your network which are permitted to do so. MAC Filtering lets you filter the device on basis of their MAC Address and you can allow or block those devices from joining your Wireless Network.
Through MAC Filtering, you can whitelist or blacklist devices on the basis of their MAC Addresses. All the wireless routers have this feature available and you can access the MAC Filtering feature from the Wireless section of the router. You can add the MAC Addresses of different devices and then choose to blacklist or whitelist them. This will prevent or allow them to join your network depending on the list in which their MAC Address is present.
MAC Filtering has a disadvantage that people who have some knowledge about MAC Address spoofing can easily spoof the MAC Address of their device and connect to your wireless network, but for that, they need to know about the MAC Addresses that are whitelisted on your network. So, MAC Filtering is a good security feature by which you can allow internet access to those devices only that are whitelisted on your network, but if you enable this option, then the Wi-Fi Protected Setup (WPS) feature will be disabled.