So, say, you have a Linksys E2000 (or whatever model, really) wireless router. You’ve got your port forwarding, your DHCP address table and all this stuff setup just the way you like it. Then you got the fancy TimeWarner Wideband service and the tech came and brought the black Motorola SBG6580 modem/wifi/router combo device.
The tech is perplexed as to what to do with your existing router (which of course was working just fine with the previous, dumber modem), plugs this instead of the Linksys and now you have a new router you can’t configure, but the Internet is really fast. Then it turns out noone (at TWC too) really knows how to put this router into bridge mode (so you can use your Linksys as a router instead), AND you can’t even access the web-based configuration because TimeWarner hides it from you (http://192.168.0.1 just quietly times out, they denied being responsible for this).
So what you need to do is:
1. Unplug coax cable from Motorola
2. Hold down the white reset button on the back panel with a pen for 30s. This resets all settings to factory defaults, including the setting that doesn’t let you reconfigure the modem ;). The modem will be auto-reconfigured once you plug in the coax cable, so don’t worry.
3. When modem is back on plug in a computer with an Ethernet cable into the modem (say, Port #1).
4. Your computer should get an IP of 192.168.0.2, and you should be able to connect to http://192.168.0.1 and login with “admin” / “motorola”
5. Now you will make some changes:
* Wireless -> Primary Network -> Disable (this will disable the wireless features of the modem)
* Advanced -> NAPT Mode -> Disable (this is one of the settings that makes the router into a simple bridge). The router will restart itself now, continue when it’s back on.
* Basic -> DHCP -> Disable
* Advanced -> Rg Passthrough -> Enabled
* Add the WAN MAC Address of your Linksys into the Passthrough list
* Basic -> WAN IP -> Static IP. Make up some IP data like 192.168.99.1 / 255.255.255.0 / 192.168.99.250 / DNS: 220.127.116.11. This way the modem doesn’t try to get an IP, allowing your computer/router to get one instead.
6. Connect port 1 on the Motorola modem to the WAN port of your Linksys. Plug the coaxial cable back into the modem and power cycle it. In theory it should just connect to the network after a little while, but mine required around 3 power cycles (you leave the modem for a min between each) to sync up all the required TWC settings.
7. Once the blue Network light comes on the modem, your Linksys should have requested and received a public IP address. If this is not the case, click to “Renew Lease” in the Linksys interface.
8. Rejoice in your victory over the poor level of customer service provided at a high price by your local cable utility. Wish you had Optimum Online (Cablevision) in Williamsburg, (they+their equipment was typically much easier to deal with).
UPDATE 9/7/2012: It seems the modems with the newer configuration don’t auto-lock themselves, so you can skip steps 1-3, or just use it as a relatively decent router. Thanks TimeWarner!