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Re: Comcast Customer Owned Modem Firmware : WAS : Xfi Advances Security (comcast)


From: Jay Hennigan <jay () west net>
Date: Thu, 16 Sep 2021 11:23:21 -0700

On 9/16/21 08:13, Tom Beecher wrote:

Does Comcast actually allow customers who own their own modems full management of the modem firmware? As far as I have been aware since my time at Adelphia 20-odd years ago, that has never been allowed by provider; all users of a given model had the same firmware enforced, customer owned or leased didn't matter.

I can't speak for Comcast, but my local cable company indeed flashes COAM modem firmware to whatever their latest approved version is at least on installation and perhaps periodically thereafter. When I bought my modem and it was first put online its firmware was upgraded over-the-wire as one of the first steps of provisioning.

Even owned modems are TTBOMK very limited on what the customer can do with them. SNMP typically isn't available on the ethernet side for example. About all one can do is parse the HTML on 192.168.100.1 (in most cases) to get an idea of signal quality, etc. If the modem has built-in wi-fi you can expect the cable company to enable it for their roaming customers to piggyback on your RF, resulting in interference even if you turn off your own wi-fi in the modem.

Leasing a modem from the cable company seems to universally be a terrible deal for the customer. DOCSIS 3.1 modems go for about $100 new retail in quantities of one. I'm sure they're much less when a cable company buys them by the tens of thousands in bulk packaging. At $10 to $16 per month it makes zero sense for anyone to rent one. Of course the phone companies did the same thing for decades with extension phones.

--
Jay Hennigan - jay () west net
Network Engineering - CCIE #7880
503 897-8550 - WB6RDV


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