I did the same when visiting Taizé in France, whose free WiFi only lasted for 15 minutes at a time! The Terminal command on a Mac, for WiFi, is: sudo ifconfig

I did the same when visiting Taizé in France, whose free WiFi only lasted for 15 minutes at a time! The Terminal command on a Mac, for WiFi, is: sudo ifconfig en0 ether xx:xx:xx:xx:xx:xx At CERN in Geneva I had a different problem: MAC addresses are registered to staff. My dad retired, and his Thunderbolt Ethernet adaptor was still registered. When I plugged it into my laptop, I not only got his MAC address, but also his device name! My shell started calling my computer a different name! If you're afraid to use Terminal, you can also install the MacSpoofer preference pane: http://www.macspoofer.com http://www.macspoofer.com