Friday, August 10, 2012

Problems with Motorola SURFboard Gateway SBG6580 DOCSIS 3.0 Wireless Cable Modem

Motorola SURFboard SBG6580 Wireless Cable Modem is an all-in-one home networking solution that's quite popular among consumers. At Cautionista, we take a detailed look whether this product has the usual shortcomings of any all-in-one product.

Here's a summary of what we found. These were actual problems seen by customers -
  • Constantly disconnects from service provider Time Warner. Connection is lost for a few minutes, every couple of hours.
  • GUI is not very intuitive. Even changing the router's password needed a lot of research.
  • The firmware that's shipped with the router - SBG6580- - caused connection drops with Comcast. The stable firmware is SBG6580- (dated 02/08/2012), however, it's extremely difficult to update the firmware of this router.

  • Wireless performance of the SBG6580 appears to be worse than that of a 2Wire Wireless-G DSL gateway, even though the SBG6580 is the newer Wireless-N technology.
  • This modem is quite light on features - only 10 port-forwarding, filtering or triggering. No QOS feature.
  • Doesn't support simultaneous dual-band - that is - you have to manually select 2.4GHz band or 5GHz band. If your home has mixed 2.4/5GHz capable devices, you need to run the router at 2.4GHz, which loses the advantage of dual-band.
  • Wireless connection is extremely flaky and seems to have a firmware update that would fix it. Motorola website says contact Comcast to update the firmware. Comcast says they don't have any new firmware. So, it doesn't seem wise to buy an all-in-one modem/router if the firmware cannot be updated to fix the router side of the all-in-one.
  • Worked OK for a few hours, but then the modem kept losing internet connection. Motorola tech suspected incoming signal strength issue, but the signal appeared to be strong based on the dB readings from the modem. However, after replacing with separate Motorola SB6120 modem and Netgear N600 router, the connection was stable.
  • The router side of the SBG6580 encountered delays and timeouts for DNS lookups which made web access very slow. ISP's signal strength was fine. The delays could be due to a bug in the firmware or might be due to a slow processor inside the all-in-one, which probably is unable to keep up with both the functions - cable modem as well as router.
  • Wireless is unstable at 5GHz, barely enough signal strength at 2.4GHz, hence not much advantage in having the Wireless-N dual band feature.
  • Modem has to be rebooted at least once in 24 hours to restore internet connection. Two pieces of SBG6580 were tried, both had the same problem. No problems after replacing with separate  Motorola SB6120 modem and Linksys E1200 router.
  • Wireless signal is weak even 15 ft away from the router.
  • The modem started dropping connections after around 6 months of use.
  • The modem died while trying to connect to wireless. Couldn't come back up again. Comcast tech that came out said they have seen several issues with the SBG6580.
  • Firmware upgrade not available to customers who already purchased the modem.
  • The SBG6580 could not connect to Cox ISP. The tech advised to purchase separate modem and router, instead of this all-in-one.


  • Many of the issues with the SBG6580 modem are possibly due to overheating.

    Here are some solutions that worked for some customers to avoid the overheating issue.
    • Locate the SBG6580 in a well-ventilated area. Keep it away from other electronic devices that may generate heat. For example, do not place it on top or near a PC that gets warm. Do not keep it in an area that gets hit by direct sunlight or near a fireplace. Place it on top of a table, and not inside a shelf.
    • Blow a clip-on fan onto the modem to cool it down. Lower speed setting of the fan should be fine. You would hear some noise even in this setting though...
  • Disable the router function on this all-in-one and just use it as a cable modem. Connect your own separate router to it. This pretty much solves most of the connection and wireless problems, since the router part of the MotorolaSBG6580 seems to be causing most of it. Here's how to do it:

  1. Disconnect the coaxial cable from the modem.
  2. Press down the white reset button on the back panel of the modem with a pen or pencil for around 30 seconds. This resets all settings to factory defaults.
  3. Turn the modem off and back on. Once it's up again, plug in a computer or laptop with an ethernet cable into the modem. It's important to connect using ethernet cable and not through wireless.
  4. Connect to from a browser on the computer, and login with username: admin and password: motorola
  5. Make a few changes:

  6. Wireless -> Primary Network -> Disabled

    Basic -> Setup -> NAPT Mode -> Disabled

    Advanced -> Options -> Rg Passthrough -> Enable

    Advanced -> Options -> Passthrough Mac Addresses -> Enter the WAN MAC address of the separate router that you plan on connecting to the Motorola modem. This is an optional step and is needed only if the router doesn't work when you first connect it.

    Basic -> DHCP -> No

  7. Now disconnect the ethernet cable from your computer/laptop and connect it to the WAN (Internet) port of your router. Leave the other end of the ethernet cable connected to the Motorola modem.
  8. Connect the coaxial cable back into the modem and power cycle it.

Alternatives to the Motorola SURFboard Gateway SBG6580:

Most people who returned their SBG6580 purchased separate modems and routers and their internet connections were stable afterwards. Here are some of the customers' choices that worked out fine for them -