Reg. D-Link 502T, it is too early to conclude that the unit is defective. Many of us are not that much expert in giving opinions. Dlink being such a big company would not bring outsuch product with such problems. As claimed earlier, if the problem is of mac address, then resetting it would do. As they are selling the unit for both windows and mac/linux users all over the country, you can not claim that it is not working or defective. Many members, even after such a long helpful directions, fail to configure it correctly and also the BSNL people are also at fault in giving directions about their side of the settings makes matters worse. So think before, going for any action against Dlink.