MAC stands for Media Access Control.
A MAC Address is a unique identifier that is assigned to every Network Interface Card (NIC).
A MAC address is composed of 6 octets. An example MAC address would be: 00:5a:95:9d:68:16.
- The first 3 octets identify the manufacturer. For example, all NIC produced by Dell will have a MAC beginning with 00:14:22.
- The last 3 octets are specific to that NIC
Routers can be set to do MAC filtering. You can create a list of MAC addresses that are allowed to connect to the network. If a device has a MAC that is not on the list, the device will be denied access to join the network.
MAC filtering can help security on a home network. But it requires a lot of administration if there are many devices.
MAC filtering is also not foolproof. It can be easy to find MAC addresses on a network by doing a packet capture on the network. The hacker can then spoof the MAC address. Most network adapter cards let you configure your own MAC address to override the burned in MAC address.
MAC filtering can be classified as “security through obscurity.” It seems like it will provide security, but once you know the method used to provide the security, then you can easily get around it.