found at: http://fascinated.fm/post/2379188731/getting-a-motorola-sbg6580-into-bridge-mode-on
Getting a Motorola SBG6580 into “Bridge” mode on TimeWarner Wideband
- Unplug coax cable from Motorola
- Hold down the white reset button on the back panel with a pen for 30s. This resets all settings to factory defaults. The modem will be auto-reconfigured once you plug in the coax cable.
- When modem is back on plug in a computer with an Ethernet cable into the modem.
- Connect to http://192.168.0.1 and login with “admin” / “motorola”
- Now you will make some changes:
- Wireless -> Primary Network -> Disabled
- Basic -> Setup -> NAPT Mode -> Disabled
- Basic -> DHCP -> No
- Advanced -> Options -> Rg Passthrough -> Enable
- Advanced -> Options -> Passthrough Mac Addresses -> Add WAN MAC address of your router 6. Connect port 1 on the Motorola modem to the WAN port of your router.
- Plug the coaxial cable back into the modem and power cycle it.
It was important for me to disable NAPT mode as the very last step. Because the modem automatically reboots when you click Apply, I was getting locked out of the modem settings because the other steps weren't yet completed.