This is perfectly legal, but hackers sometimes use this tactic so that criminal activities cannot be traced back to them. one for your wifi connection and one for your ethernet connection. A device can have multiple MAC addresses, e.g.This allows a router, for example, to know where to send the data back to. The MAC address is an identifier for other devices in the neighbourhood.This makes your device recognisable to other devices in your network, so that the data traffic between those devices is managed properly.
A MAC address is a unique identification number, which is the network module in your device, with which you can connect to the Internet.
