I just recently switched from ATT DSL to Comcast. I have successfully installed my new Motorola SBG6580 modem / router. Everything is working fine except that I can't seem to get my external switch to provide IP addresses to the devices connected to it.. I still require several hard wired connections and the Motorola only has (4) 10/100 ports. I have one of those ports connected to an external Linksys switch; the one that I previously used with my ATT DSL setup. I have also tried several other switches I have and none of them seem to work. It seems as if the Motorola device is blocking (somehow) the use of these external switches, limiting me to only 4 hard wired connections.