Thursday, October 11, 2012

Coaxing a Motorola SBG6580 into “Bridge” mode

Okay, I have covered ATT's modem router combo.

Now we are going to look at putting the new Time Warner high speed internet modem router combo into bridge mode so that you can use your own network equipment with it.

The Time Warner technician who connected my service did not understand what bridge mode was. After some discussion and explanation, he disabled the wifi transmitter but did nothing else.

This left my dd-wrt router being assigned a local ip address... which is useless to me.

Here we go...
  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. The modem will be auto-reconfigured once you plug in the coax cable.
  3. When modem is back on plug in a computer with an Ethernet cable into the modem.
  4. Connect to and login with “admin” / “motorola”
  5. Now you will make some changes:
  6. Wireless -> Primary Network -> Disabled
  7. Basic -> Setup -> NAPT Mode -> Disabled
  8. Basic -> DHCP -> No
  9. Advanced -> Options -> Rg Passthrough -> Enable
  10. Advanced -> Options -> Passthrough Mac Addresses -> Add WAN MAC address of your router.
  11. Connect port 1 on the Motorola modem to the WAN port of your router.
  12. Plug the coaxial cable back into the modem and power cycle it.
  13. Power cycle your dd-wrt router.
  14. Check to see that the external ip has now been applied to your dd-wrt router.

Your SBG6580 should now be in bridge mode.
Your dd-wrt router is now given an external ip.



  1. Before switching to this, I was getting about 40% packet loss using the standard modem/router combo, and my connection overall was just terrible (not to mention how terrible the wireless is). Now that I get to use my dd-wrt again, my wireless is wonderful and I am seeing no (or extremely little) packet loss.

    However, I've lost port forwarding. If it's a true passthrough, the port forward assignments on the dd-wrt should work, right? Is there anything else I need to change to get that working?

    1. If you have the Motorola in passthrough/bridge mode, then the port forward assignments are taken from the dd-wrt router. The Motorola should be acting like a modem and have no routing functions.

  2. This also fixed my packet loss problems, thanks! I was getting packet loss when trying to use a router behind the gateway using just DMZ. This worked fine for over a year, but recently I started getting 40% packet loss. I guess there was a firmware update that broke something. My port forwarding works fine.


Blogger won't auto-notify the author of your comment, but he does reads through them every few days to post replies.