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Getting a Motorola SBG6580 into “Bridge” mode

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Getting a Motorola SBG6580 into “Bridge” mode on TimeWarner Wideband

  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:
    • 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.
  6. Plug the coaxial cable back into the modem and power cycle it.

Thanks! This is perfect and exactly what I needed...


Or you could just use the "double-DHCP" trick. Plug your own device's WAN port into the Motorola port #1. Let it grab a default DHCP address of and offer route via Ensure your own router device is in another range like, usually by default. Set your DNS and configuration settings on your router device and plug all PCs into your own router. Don't plug anything into the Motorola except the WAN port which should connect to your router. You are then good to go :) Of course, you'll still want to disable the Motorola wifi if your own router has it already...

saim80 commented Sep 3, 2012

Wow, Thanks for sharing. This is exactly what I needed.


I don't recommend "double-DHCP" which is just an extra level of unnecessary NAT indirection.

udev commented Oct 17, 2012

Awesome! Thank you. This is exactly what I wanted/needed.

A note to anyone who follows these directions and can't get internet access initially:
I followed all the steps and had to power cycle the modem with the router still connected and on. WAN access didn't kick in for a minute or two but these instructions did work ^_^

jgarber commented Nov 5, 2012

Comcast pushed SBG6580- down to me and the next time the power dipped, bridge mode stopped working. "Rg Passthrough" is gone and despite all I've tried, I can't get the modem into bridge mode. Tried double NAT and my Airport router complained (but worked). Couldn't get Facetime to work, though. Motorola's firmware is just a mess. If I can't get this working, I may have to buy an Arris, probably a WBM760A.


When I Disable NAPT it go to a reload screen and I don't have access anymore. I have to reset to have access again. Any idea what's going on?

Is it possible to use as a bridge just with wifi connection? Not using the coaxial?



Worked perfectly. Thank you!


Thanks so much, this helped big time!

Dimenus commented Jul 9, 2013

Awesome post. Much appreciated.

jryans commented Jul 12, 2013

Thanks for this, very useful!

cdmckay commented Jul 17, 2013

On my SBG6580, all I had to do was disable NAPT mode (click the Apply button immediately below it) and that switched it into bridging mode. The SBG6580's IP will then change to and you can login there if you need to. When you're ready, plug in the coax, cycle your modem, and plug it into your router's WAN port. It should work shortly thereafter.


THANK YOU!!! That's a really intuitive interface.


After turning of napt mode the interface ip changes to to log in. Otherwise I used the instructions and I'm typing this from one in bridging mode now.




I turned off NAPT but found I could only connect one computer. I have three in the home besides the Server. Or is this this only used for connecting a second Wireless Router? The first creates the Bridge and the second connects all your PCs?


I had the same results as cdmckay. I got it to work by disabling NAPT mode and thus the modem restarting. I can then access but there are no settings worth changing in there. I plugged my router into slot 1, unplugged the power from the SBG, plugged in the COAX and plugged the power back in. that is the order that I had to do in order for it to work. for AesopsRetreat I think the purpose of bridge mode is to disable the first router. Thus making it only act as a modem. Meaning your devices would have to be connected to the second router.


Thanks for all the comment (especially djstrikes3)! It worked as advertised. 👍 Once I plugged in the other router I bought, I was able to go to and log into the Motorola (as described above).


Once Motorola SBG6580 is in Bridge Mode, if the new router can't connect to the internet, then you might have to set the router's MAC address to match Motorola SBG6580's MAC address. This is because some ISPs only allow certain MAC addresses to connect.

In my case, I set my router's MAC address to the Motorola SBG6580's "GATEWAY MGMT MAC ID" and I was able to connect.


For the life of me, I simply can't vision why somebody would want to do this procedure.
Buying something and then stripping it of 98% of it capabilities just doesn't make sense to me.
If all you want is a modem, then why not just buy a modem.

Just sounds like a lack of understanding in what the end result should be.


@electroman00... Because people's needs change. I bought my SBG6580 before I had a roommate who liked trading copyrighted stuff using BitTorrent. Comcast put me on notice of violation and I couldn't trust the roommate to voluntarily stop his activity. I needed to put a router between the roommate and the Internet that allowed for application blocking. Since the SBG6580 firmware provided no reasonable avenue for that I ended up putting it into bridge mode and setting up a dd-wrt router behind it that allowed application blocking (among other things). It was either that or find a new roommate. The bridging option seemed easier.


@jlpeifer you don't have to put the modem into a bridge mode to do what you want. The SBG6580 has a provision for connecting routers to it and passing through aka bridging internal to external.
IOW doing the procedure here isn't necessary because the SBG6580 has a provision for doing what everyone wants.


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.


The reason people would want to disable the router capabilities of a modem is because they're generally underpowered as a router. There are quite a few more powerful and efficient routers, even at the SOHO level.

W3DCB commented Jan 12, 2016

RE: Motorola SBG6580...Port Forwarding Problem....Hi everyone. I am new here. I have a question about this "great" little router. Actually, I don't think that the problem is in the router. I think that the problem is my ISP at my local cable hub...not at my home location/router & LAN...We had a lot of trouble in my neighborhood recently. Xfinity was working in my neighborhood for weeks. They seem to have gotten internet speed back up and internet connections are not dropping every few minutes as they were for many weeks. Ever since Xfinity "worked" in my neighborhood, ports that I open through my router via Port Forwarding can not be found via or via any software that I am using remotely to access my various ports. For example, I have opened ports for my Moxa 16-Port RS-232 Server. Its local address is Ports 4001 through 4016 are opened in Port Forwarding in my router. However, no one can "see" my opened ports. I used "" Some of the old standards are visible like 8080, but none of the other Ports that I have tried to open are visible. How would I prove who is at fault here? Any ideas? I have been on the phone with Xfinity for hours. Most of the Techs have no idea to what I am referring. They tell me that I must not know how to open ports in Port Forwarding. I explain that I have been doing this for several years and they have no idea what to tell me. Any ideas would be helpful...Thank you in advance Daniel.



People need to place the modem often in bridged mode when dealing with VOIP applications, gaming (i.e. xbox one complains about strict NAT), configuring a vpn, etc to avoid double NAT scenarios. When in bridge mode the external interface of the device behind the SBG6580 will receive the Comcast Public IP that was once assigned to the external interface on the cable modem. The SBG6580 also had a known issue with it's wireless (I believe with certain firmwares) that it would drop the wireless network intermittently - you could plug in via a wired connection and connectivity would work without issue. The Firewall and other features on the SBG6580 are also lacking to say the least.

blajoie commented Apr 30, 2016

This did it for me - thanks @cdmckay

"On my SBG6580, all I had to do was disable NAPT mode (click the Apply button immediately below it) and that switched it into bridging mode. The SBG6580's IP will then change to and you can login there if you need to. When you're ready, plug in the coax, cycle your modem, and plug it into your router's WAN port. It should work shortly thereafter."


"The SBG6580 also had a known issue with it's wireless (I believe with certain firmwares) that it would drop the wireless network intermittently"

I have started seeing an issue like this. Any references you can provide? TIA.

  1. "Rg Passthrough" is gone for me but doing everything else worked great.
  2. You can do this all without an ethernet connection if you use your new router as a wireless bridge to the Motorola, then at the last minute set it back to be an actual router.

My firmware version is SBG6580-
I can access the control panel via and using admin/motorola for the login/password.
There a section in Basic > Setup, called Primary Mode. It has a Gateway Mode setting with the options of 'Routed' or 'Bridged'.
Anyone know if it's as simple as just switching this over to 'Bridged' in order use with another router?


i am wondering the same thing, @huntermaclean. did you find out?

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