Find your MAC address with ifconfig
You can find the MAC address of your system at the command line by using the ifconfig command. The ifconfig command will show you information on all your network interfaces. If no arguments are given ifconfig displays the status of the currently active interfaces.
You have to run this command as root or use sudo.
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Find the MAC address on a Windows machine
For whatever reason lets assume you find yourself on a Windows machine and you need to obtain the MAC address of its network adapter. Do the following.
Go to Start -> Run which will bring up a text box. In this box type cmd. A command prompt will appear.
Type this is the terminal.
ipconfig [...]