Also, if you are on Comcast and have a home hetwork, Comcast can't see anything past the modem, as your router's firewall won't let them. When you install a home network, Comcast asks for the MAC address of the router. Your IP address in a home network is the address of your network card.
Does the poster want to set an FTP server or, what. He refers to FTP, but what does he want to do?