In comp.dcom.modems.cable
wrote:
> The update is done when Adelphia send a signal to the reboot the UBR924
> and add the following line to the config file, under the interface
> cable-modem0:
> cable-modem boot file ubr920-k9v6y5-mz.122-5.bin 68.168.0.19
> where 68.168.0.19 is the ip address of Adelphia tftp.
> I coudl try to block the port 69 (tftp) however I doubt that works,
> because the router (UBR924) execute the config file before to go to the
> filter level, where I can tru to stop any tftp traffic
This is all done through DOCSIS and it's unlikely that you will
be able to prevent it from happening. It's been a while since I used
mine, gave up on it really after moving. It was working fine with Time
Warner on the east coast but never worked right with Comcast in mid-west.
I had to upgrade to a certain IOS before TWC worked because they were
trying to set a bunch of crap via SNMP that the previous IOS knew
nothing about. I suspect that it didn't work when I switched to Comcast
due to similar issues but didn't have time to mess with it. One of the
techs thought it was possibly due to them going from QAM 64 line coding
to QAM 256 (more bandwidth) recently, but I checked and the UBR924 does
in fact support QAM 256 so that wasn't it.
These are great, they work well, have a couple of H.323 phone
ports if you want to mess with getting those working, do real routing
and tricks that are not possible with "consumer friendly" routers. The
drawback is that they're usually never "officially supported" by any
cable providers these days and even if you get it working your luck will
probably eventually run out. Even though DOCSIS is a standard, there
seem to be enough variables in the management side, that your
modem/router may not work right depending on how much they try to
"mangage" (or, is that mangle?) it.
My advice, if you want to stick with Cisco for the power (and
quirks) of IOS, is to go find a nice cheap dual ethernet Cisco 8xx,
16xx, or maybe even an old 2514 (if you like to hear fan noise) and
stick that behind a Motorola SB5100 or similar.