The SB5100 is NOT a router. It is a cable modem ONLY. It connects to your broadband CATV line, and provides a single ETHERNET link downstream. This link has a cable-provider assigned IP address. Likely a dynamic address which changes periodically.
There are no setup features per se on a SB5100. That said, there typically is NO FILTERING enabled either, so nothing that needs to be SETUP for it to transport ALL traffic to your PC.
except for that it DOES have a firewall (as per the description on the pages within the device's internal memory) which cannot be disabled or circumvented and claims to be a router for up to 32 computers (if one has a switch.) however, its dhcp server only operates when the modem is offline (as per the description) which seems retarded. basically, the sb5100 sucks balls, 5100 times.