When you first get a cable modem, or if you move house, you don't get a "proper" IP address, you get one that's sort of designated as no-man's land. Back in February, not long after I'd moved house, without warning my IP address changed from a valid address to one in no-man's land. I tried visiting the moving house URL and entering my details again but I kept being told my MAC address wasn't valid. Tech support had to remove my modem's MAC address from the system and add it again. Total mystery as to why I was suddenly assigned a no-man's land IP address. So, yes, strange things do happen with NTL
