On 2016-01-26 03:07, Ken Cito wrote:
So, it seems that Comcast is the guilty culprit, because Comcast is
*requiring* (it seems) two exact MAC addresses:
a. One (real) MAC for the DOCSIS3 modem, and,
b. Another (bogus) MAC for the "computer" that connects to the modem.
(Where this "computer" is the router itself.)

Is that correct yet?

Maybe.

I don't have comcast, I live in another country. But I'll try to make
educated guesses. :-)

There are several reasons to have to clone MAC addresses. One quite old
reason was that the ISP wanted us to connect a single computer. They
would provide a modem of some kind with a single ethernet socket for a
single computer. They would identify this computer by its MAC address,
and refuse to provide service if it changed. Stupid, IMHO.

But people inserted a router in there, to allow more computers, using
NAT. This router had to make the ISP think that it still was connected
to the same single computer, thus we would clone the MAC address of the
computer into the router outside facing port. And of course, the router
has to remember this (save settings), or on power reset it would not work.

I think that is your situation.

It is possible that it would accept the new (unchanged) MAC address of
the router after sometime, without doing anything. As I said, I don't
know comcast. Try rebooting both modem and router, later connect the
computer.


Another situation is that the ISP may identify the MAC address on the
external port of the modem or router connected to the cable, typically
provided by them. If you buy a different router, it will not work unless
you clone that external MAC address. This happens with one provider in
my country, I understand.

--
Cheers, Carlos.