I have the weirdest problem I have ever experienced on my macbook air. I am able to connect to my network just fine and access the internet. But if I move more than about 10-15 feet from the router (airport extreme) the macbook reverts to a self assigned ip address and I can no longer connect to the internet. As soon as I move back to within 10-15 feet it will grab an ip address again. I also have a macbook pro and ipod touch that have no issues connect to the router anywhere in the house. I have tried restarting the computer when it cannot grab the ip address to see if possibly the airport card just can't pick up signal in those spots but I can clearly see my network in the list of available networks with full signal. I have re-formated the computer with Mavericks and Mountain Lion and even with a fresh install I still run into the same problem. I have also tried to assign it a static ip address but again as soon as I move out of that 10-15 foot radius it looses the static ip. Any other ideas?