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Re: Modem MACs and how ISPs view them, was Re: on the verge of …



My sanity requires top-posting:
See your very last sentence:
You go to an HTTP port at a non-routable address which should be on the box. Usually on a yellow sticker. Now I've never tried to program that interaction but I bet it could be done. For comparison, biggish Juniper routers are configured by salt/saltstack these days. Just like your linux server farm. 

But maybe start trying with wget or curl. Work your way up the language hierarchy.  HTH.

On Tue, Mar 9, 2021, 2:54 PM David Wright <deblis@lionunicorn.co.uk> wrote:
Change of topic overdue:

On Tue 09 Mar 2021 at 00:12:40 (-0500), Felix Miata wrote:
> David Wright composed on 2021-03-08 22:37 (UTC-0600):
> > On Sun 07 Mar 2021 at 21:37:37 (-0500), Felix Miata wrote:
>
> >> Having != connected. The extras are spares. :)
>
> > I realise that, but if your service were to become unsatisfactory,
> > then before you complained, you'd want to check that it's not your
> > modem at fault. Would you expect your spare modem to work, because it
> > has a different MAC from what's expected by the ISP's end of the line.
>
> > (Similarly, if your modem were to burn out, which is what happened
> > to mine after seven years.)
>
> Whenever I get a mind to, I call my ISP, tell them I'm changing modems, and what
> the new MAC is. It gives me some confidence it's still useful. If there's a
> problem they or I think a modem switch might shed light on, I do the same.

Perhaps I'll try that as things settle after the pandemic.
I changed our modem within two hours, but that was with a visit
to the office (2½ miles), and the replacement one is rented.

I'll change it out when not every day is a zoom day. At the
moment, the internet is still about as important as running
water.

On Tue 09 Mar 2021 at 08:12:47 (-0500), rhkramer@gmail.com wrote:

> I have DSL service, and a spare modem that I've occasionally put in service
> (for testing the "main" modem) and have not had to notify the ISP.  (They were
> both provided by the ISP (Earthlink).)
>
> I don't know if cable modems would work the same -- I don't know if the ISP
> sees the MAC address on a DSL line.

You may well have login authentication. Perhaps you have the
credentials configured in the router, and forgotten that they're
there.

On Tue 09 Mar 2021 at 13:35:18 (+0000), Joe wrote:
> On Tue, 9 Mar 2021 08:12:47 -0500 rhkramer@gmail.com wrote:
> >
> > I have DSL service, and a spare modem that I've occasionally put in
> > service (for testing the "main" modem) and have not had to notify the
> > ISP.  (They were both provided by the ISP (Earthlink).)
> >
> > I don't know if cable modems would work the same -- I don't know if
> > the ISP sees the MAC address on a DSL line.
>
> I used to change routers without telling anyone, but that was years ago.

That doesn't add a lot of information as you've not mentioned
the type of connection. (I presume router means a modem/router
combination.)

> As an anecdote, I recall a BT service/router which literally would not
> work if it detected another NAT on the LAN. It was in a client's
> network, and I had to reconfigure things to work without the Debian
> server acting as a firewall. If it had been my network, the wretched
> thing would have gone back instantly, my network runs through two NATs
> and that isn't negotiable.

I had a BT service briefly (replacing a plusnet service running over
a BT line), and they supplied a Homehub. AFAICT the authentication, if
any, was "burnt" into modem and router combination, and the T&C didn't
allow for you to swap it out.

On Tue 09 Mar 2021 at 10:07:39 (-0500), Stefan Monnier wrote:
>
> You should be able to change the MAC used by your device, i.e. you
> should be able to arrange for both devices to expose the same MAC so
> your ISP won't notice the difference.

Quite possibly, though I'd rather not have to do that if possible.
As well as the MAC, there is also a Serial Number and a Modem Number,
and AIUI the device logs changes such as these that are made, at
least as long as they stick (perhaps until a factory reset?).

What software would I need? For example, how would I alter the MAC
address on this Cicso DPC3010 modem? If I connect a computer to its
Ethernet port, all I see is the seething morass called the Internet.
How do I talk to it, ie to the modem itself?

Cheers,
David.


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