I think the NIC address is bound to the ip by roger's DHCP server for at least one hour or more. It seems that every time you try to connect to the internet. you NIC address is recorded by the server. one hour later, if you use the same computer accessing the net, you will be connected while all the other computers are refused. I don't think it is malfunction of the server. Now I have to apply for another IP from rogers , which cost me extra 9.99$.