Tag: mac address

Leopard ByHost Plist Preference File Naming Convention Change

In Mac OS X 10.4 Tiger some system preferences were unique to a particular computer and so were named using a naming convention that included the MAC address of the first network device in the computer (en0). In Mac OS X 10.5 Leopard this naming convention was changed to use a different unique identifier other than the first network adapter’s MAC address. Leopard now uses something called the UUID for this unique identifier. You can determine a UUID of a Leopard computer by running the terminal command:

ioreg -rd1 -c IOPlatformExpertDevice | grep -E '(UUID)'

Terminal

OS X – How to Change the MAC Address

Changing the MAC address of your network interface card can be useful for a number of things. Here is how you change it in both Tiger and Leopard:

For Tiger (10.4.x) open up the Terminal application and run the command:

sudo ifconfig en0 ether 00:00:00:00:00:00

where en0 is the network interface you wish to change the MAC address of, and 00:00:00:00:00:00 is the new MAC address you want the interface to use.

For Leopard (10.5.x) open up the Terminal application and run the command:

sudo ifconfig en0 lladdr 00:00:00:00:00:00