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

Thu Sep 16 18:23:21 UTC 2021

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 at west.net
Network Engineering - CCIE #7880
503 897-8550 - WB6RDV