By the way, your post makes it sound like you think ethernet plugs in your house are necessary for setting up the modem itself, which is not the case – modem connects to Comcast Coax, and provides access via the ethernet ports and wi-fi. A common home installation is to put the router in the home office so ethernet is available for "the important stuff" and then use wi-fi to get to the rest of the house. Or, some people put it in the entertainment room because streaming is "the important stuff".
Hello. Tried setting up my XFi Gateway yesterday only to find that the house I moved into contains old modular phone plug-ins (rj-11), and no regular Ethernet plug-ins (rj-45). Is there a way I can get a technician to somehow set one up for me?
In my case, I used flat Ethernet cable and strung it all over my house. Since it's flat, I went under carpets and rugs and doorways with no issue.