MAC Address

A Media Access Control address identifies a wired or wireless network interface on the local network. Windows displays it as the Physical address in ipconfig /all and in an adapter's hardware properties. Routers may use the value for reserved IP assignments, access lists, or device labels, which is why replacing an adapter can change how the PC appears on the network. Windows can also use randomized addresses on Wi-Fi networks to reduce tracking between locations. That privacy feature may conflict with networks that explicitly approve one address. Before changing adapter software to fix a connection, note whether randomization is enabled and whether the router has a reservation tied to the old value.