2018-12-14
The Advent of Void: Day 14: macchanger
macchanger(1) is a tool that helps you setting a random but correct MAC address on a network interface.
MAC (Media Access Control) addresses are an unique identifier assigned to network interface controllers. They are used at the data link layer to address NICs in a network. Every NIC has a (pseudo-)unique address burned in. This makes it easy to recognize and identify your device if you connect to a network or even if your WiFi adapter is only scanning for networks. To secure a device from tracking you can change the mac address. Also changing the MAC address in high availability setups can be helpful: Taking over a MAC address from a crashed systems on the failover can reduce the downtime in some scenarios.
In both cases you can use macchanger to set new mac addresses on a NIC.
To show the current MAC address of eth0
run the following:
$ macchanger eth0
Current MAC: 18:5e:0f:31:7f:cc (unknown)
Permanent MAC: 5a:68:a5:ca:cd:c3 (unknown)
To change the MAC address of the device to a completely random one add the -a
flag:
$ macchanger -a eth0
Current MAC: 18:5e:0f:31:7f:cc (unknown)
Permanent MAC: 5a:68:a5:ca:cd:c3 (unknown)
New MAC: 00:21:d5:da:a4:bd (X2E GmbH)
To set a static MAC address on your device use the -m
option:
$ macchanger -m 02:42:99:aa:48:47 eth0
Current MAC: 18:5e:0f:31:7f:cc (unknown)
Permanent MAC: 5a:68:a5:ca:cd:c3 (unknown)
New MAC: 00:21:d5:da:a4:bd (X2E GmbH)
For more information about macchanger please consider the manpage