The MAC address is a unique six-byte address that identifies hardware devices such as wired and wireless Ethernet adapters, Bluetooth adapters, etc. It's usually presented in the following format 12:34:56:78:90:AB. Almost without exception all devices that have a MAC address will have the address printed on the original packaging. However, it may or not be on the product itself. On a Pi you can find its MAC address by looking in the following file:


For example, you can display the address for eth0 using:

cat /sys/class/net/eth0/address

Alternatively, you can use the ifconfig command to display the address for all your adapters:


Or, you can be specific and just specify one adapter:

ifconfig wlan0

Why Would You Want To Bother?

The MAC (Media Access Control) is often used when managing LANs. On wireless routers it can be used as a security mechanism and filtered so that only known MACs are permitted to connect. It is also required in a DHCP server if you wish to set up a reserved IP address. On managed LAN switches the MAC address of a lost, stolen or rogue device can be blocked from connecting.