Getting a Motorola SBG6580 into “Bridge” mode

gistfile1.md

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

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 http://192.168.0.1 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.

I am having trouble getting my SBG6580 to work properly in bridge mode. I have firmware SBG6580-8.9.0.1-GA-00-092-NOSH. I followed the instructions above by @mikew and after I hit Apply, I cannot log into the SBG6580 using 192.168.100.1. When I connect my router to the modem, it says there is a problem with the DHCP from the ISP, but I can't log into the modem to check what the problem is. I have tried about 10 different times with slight tweaks, but get the same result every time. I contacted Comcast about it today and they said they couldn't log in because it is a customer owned router. It sounds like setting the SBG to bridge mode should be pretty straight forward from all the different posts I have read about it (most of which had the same instructions). I am wondering if I am missing something or my SBG6580 is a lemon and won't function as intended in bridge mode. The router I am trying to connect to the bridged SBG6580 is an Asus RT-AC87U with the most recent AsusWRT Merlin build. The Asus router works fine when the SBG6580 modem is set to route mode, but has no connectivity after the SBG is switched into bridge mode. If anyone else has experienced a similar problem, please help!

I saw some mention they no longer have access to login to the device after disabling NAPT mode (or enabling Bridge mode). I learned the hard way...always disable wireless first then go back in to disable NAPT, disable dhcp, and enable Rg Passthrough. When your router or pc pulls a public IP address, you know you've done it right.

I am having the exact issue @jonechuc is describing with a Linksys EA6350. Lost a hard earned Sunday working on this, and settled on letting it stay on "Routed" mode with the firewall off. In bridge mode, with a computer directly connected, I get a public IP, but no connectivity. So strange.

firmware SBG6580-8.9.0.4-GA-02-141-NOSH is missing option "Gateway Mode" when attempting to put into Bridge mode, per Arris's own instructions. Epic Fail.

https://arris.secure.force.com/consumers/articles/General_FAQs/SBG6580-v8-5-x-Bridge-Mode-Setup/?l=en_US&fs=RelatedArticle

@cdmckay's comment mostly did it for me BUT I also needed to set wireless to off. Another issue was that my new separate router wasn't broadcasting any networks, which I thought was the fault of the SBG6580, but actually I had to factory reset my router and then it broadcasted its networks.
So in full, these steps worked for me:

1. unplug coax cable
2. reset SBG6580
3. connect computer with SBG6580 via ethernet (although this could've been done from the beginning too)
4. connect to 192.168.0.1 and enter "admin" and "motorola" (or whatever else you set these to)
5. set
   -Wireless to Disabled (not just the primary network!)
   -Basic -> Setup -> NAPT mode to Disabled
6. if you still need access to the landing page, use 192.168.100.1 . Otherwise, plug in the coax cable, take out the ethernet cable to your computer and power cycle it
7. connect the SBG6580 in bridge mode with the new router via ethernet cable and then factory reset the new router if necessary
   ezpz