Is it possible to configure my SBG6580 cable modem to have wireless enabled and to also have a wireless router connected and running its own wireless network? Kind of a weird situation, I won't go into it, but we need the main network, a guest network, and a 3rd one if we can swing it.
All I can see online is disabling the wireless on the SBG6580 and bridging the modem, but I want to keep the modem's wireless enabled...
Running a second wireless network is the easy part you just hook up a router or ap and set your ssid and channels to what you like and all will work.
The larger issue will be separate networks. If you run as a AP then they are all on the same network. If you run as a router then you only sorta have 2 networks. The network behind the second router will appear to come from the wan address of the second router. In this case the machines in the second network can get to the first and the internet but the reverse will not work without port mapping.
The only way you get 2 networks if you want them isolated will be to have that function done on the cable modem/router but this particular one does not have the ability to run multiple networks.
You need to turn the router in to a AP/switch, by disabling anything to do with acting as a router, DHCP, DNS, firewall, UPNP etc. set the routers LAN IP to one that matches your existing network, leave the WAN on AUTO or set it to a non-existent IP setup. Connect router to modem via LAN ports NOT WAN. The router will look like any other network device, but will route data to and from the modem. You will have to give the router a different SSID.