Things You'll Need
Instructions
Make sure your Comcast modem is connected and working properly. Connect your cable line to the cable input on your modem. Connect one end of an ethernet cable to the output on your modem. If you are connecting your modem to a router first, plug the other end of the ethernet cable into the input port on your router. Plug another ethernet cable into an output port on your router. You will connect this cable to your Xbox.
Connect the ethernet cable, either running from your modem or your router, to your Xbox. Plug the cable into the ethernet port located on the back panel of your Xbox.
Turn on your Xbox and select "Settings" from your Xbox dashboard.
Select "Network Settings" and click on "IP Settings." Comcast uses the DHCP protocol to assign IP addresses, so select "Automatic" from the IP settings. Go back to the previous menu and select "DNS Settings." Select "Automatic" here as well.
To create an Xbox Live account, select "Xbox Live" from the dashboard. Follow the on-screen prompts to create your account.