If you’re Internet connection from Comcast works fine when it is connected directly to your computer, but does not work when connected to your router Comcast will not help you. In order to set your router to correctly work with Comcast some changes are needed from the standard router setup. First thing you will need to do is log into router. If you own a Linksys you will log into it by typing into the address bar of your browser 126.96.36.199. For any other brand it is either the same or 188.8.131.52. Once you have the login screen for your particular router, you will type in your login and password. For most routers the default for both settings is admin. Comcast offers what is called a dynamic IP address. If you are following the setup wizard this is the choice you will make. The key for connecting with Comcast is the Mac address. You will have an option button clone Mac address. You must refresh that address in order to be recognized by the Comcast modem.
Your wiring setup goes from the Comcast modem, to the WAN port on the router, from one of the four out going ports to the back of your computer into your LAN card.
If you have changed service from DSL to cable you may have one of the older PPOE accounts. These required a login along with a password. You must reset the router from this account to dynamic IP. It is also a good idea to reset your modem, router and your computer to assure the IP address has been released. All of these are reset by simply turning them off, letting them sit for a minute and turning them back on. If your router and modem do not have a on-off switch, simply unplug them.