My cable internet provider limits internet access to one MAC address only, in my case it's the one from my old laptop. I'd like to change the MAC address of the ethernet card. I managed to change the MAC address on the Windows partiton, but I can't change it in Mac OS. I'm quite a newbie in Mac OS. I tried it through Terminal by using the following command: sudo ifconfig en0 ethernet xx:xx:xx:xx:xx It seems to change the mac address (or ethernet ID as it is called in the network settings panel), but when I go to the network setting panel, the mac address stays unchanged. Can anybody help?