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New Member

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1 Message

Wed, Mar 10, 2021 5:11 PM

Arris SB8200 cable modem requires password after Comcast update

Might Comcast pushing an update to my own cable modem have changed the modem's login behavior or overwritten the default login password?

On installation my new Arris SB8200 cable modem allowed viewing modem details on 192.168.100.1. Now the modem suddenly requires login credentials at 192.168.100.1.

Arris claims that a factory reset using the modem's reset button restores the default login, where user is admin and password is the last 8 characters of the serial number on the modem's label.  However after a factory reset login is unsuccessful, using the default username and password. 

A Comcast Business Support rep stated that Comcast does not update modem firmware, which seems most unlikely. So could a Comcast firmware update have changed the default user name or password after the factory reset?

Official Employee

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29 Messages

1 y ago

Hi,@doc_jones! The information the specialist provided to you is correct, we do not update the firmware on modems that are not ours. In a case like this, we would normally direct you back to the manufacturer of the modem. Such as doing a hard reset as they suggested. To confirm, have you already done the factory reset? 

New Contributor

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2 Messages

1 y ago

I can't comment on the user/pass issue.

However, the answer over the phone and the answer from Comcast above are incorrect. The CMTS (ie equipment owned and managed by Comcast) WILL upgrade your SB8200's firmware if it does not comply with the policies on the CMTS. Comcast controls which firmware your SB8200 runs. This is managed via DOCSIS management tools and the SNMP protocol. There is no way to change the firmware version from the client side (ie the web interface you see on the modem). It can ONLY be controlled via a CMTS on the cable plant side with the proper chain of trust via certificates.

And yes, Comcast did recently deploy a new firmware version affecting access to the web interface. The equipment may be yours, but they are responsible for fixing the issue they caused by changing firmware. I've had interesting situations where my modem was unable to successfully switch to a new firmware version and had to find a Comcast tech via forums who could fix it by hand.

Good luck!

New Contributor

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3 Messages

1 y ago

Thanks for the clear explaination. I'll follow up with Comcast support when I am on site to push that reset button. Any tips on how to move up the Comcast support levels when I am told to contact Arris because it isn't Comcast's responsibility?

New Contributor

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1 Message

1 y ago

Same problem here.  The new firmware and/or configuration (boot file) push from xfinity has rendered my internet access completely unstable.  Randomly switches from DOCSIS 3.1 to 3.0 to 3.1... all day long.  This causes huge packetloss and latency and also usually causes zoom to break.  Which of course in pandemic times is a HUGE PROBLEM.  No internet, no work.  No work, no income.  I wish Arris and Xfinity would resolve this.  Its so clear this was due to a recent firmware/bootfile push.  

New Contributor

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3 Messages

1 y ago

I too notice my modem toggles between DOCIS levels with periodic disconnects. Thanks for the tip that an update may be causing that also.