@Riley_S so for some reason Xfinity can not reset the MAC address of a modem without activating one on its place. I had to buy another modem jusr for that. Everything is working now.

@Riley_S I have tried both and it just never gets an IP address. Tried auto select. Then reset and tried dynamic. Never gets communication with the modem. Other than weak signal while the modem is...

I've tried everything on this website to get this router to work with my sb8200. It will not get an ip address from modem. All zeros. tried the power cycling. The removing coaxial cable. Mac cloning....