I just purchased a TC and was unable to get it to connect to the internet (error was that it had an invalid IP) when I plugged it into my cable modem (Motorola Surfboard SB5101). I have a PhonePower adapter for my VOIP and if I use that as an intermediary, then my TC successfully connects to the internet and I can use the TC as both wireless network and TM back-up. I have been in contact with both Apple and my ISP, Wave Broadband, and both indicate it is not a problem with their product. Obviously both the cable modem and TC work, but for some reason they don't communicate if connected directly to one another. I have reset/rebooted all devices and still it won't work if the TC and modem are connected directly to one another.

I thought about buying a new cable modem to see if that would fix the problem, but I'm really trying to make what I have work, since each device does work. It just doesn't work when set-up the way I think it should be set-up.

I asked my ISP to release my MAC address of my old router and they said by resetting the modem on their end it does that. Apple said it sounds like a provisioning issue with the modem, but I don't understand what that means.

Any tips, input, advice would be greatly appreciated.

Also, if you think it is a problem with the cable modem, which brand do you suggest I get. What has been known to work seamlessly with TC.