[K12OSN] Cable net connection problem

[David H. Barr]

On Thu, Apr 3, 2008 at 10:32 AM, Les Mikesell <les at futuresource.com> wrote:
> Barry Cisna wrote:

> > Done a fresh install of K12LTSP/FC6 for an individual for home use for
> > their kids to use. They have cable internet for the first time. I was
> > there when the tech came and done the hookup at their house. I bought them
> > a brand new Motorola 5120 cable modem. Never could get their fresh FC6
> > server to do internet,although the ip numbers/dns numbers look correct. I
> > can plug an xp laptop into the same new cable modem and internet comes up
> > fine. I DID disable the linux iptables for testing BTW.
> > I can not ping anything by even IP address? Also strange thing,i never see
> > the "activity" light flicker on the cable modem when plugged into the
> > K12LTSP server?I talked to the tech at the head office and " we do not
> > support Linux":( I never checked to see if this cable co is setup for
> > DOCSIS1.1 or DOCSIS2.0 ( which I haven't read a thing about). Of course I
> > have done a network restart several times,and simply no webpages ever
> > display. As said earlier on the Windows XP laptop it comes up via dhcp
> > very quickly.


>  I think cable companies can restrict the MAC addresses that will get a DHCP
> address though a cable modem so it the xp box was the first thing that came
> up it may be a long time before it will give an address to anything else.
> The quick fix is to use a home NAT router behind the cable modem.  Most of
> them have an option where you can set the visible MAC address on the public
> side to the one the cablemodem already expects  - and you can use more than
> one computer behind it.
>
>  Most cablemodems have a web service at 192.168.100.1 (and at least the
> surfboard models don't even care that you aren't on that subnet yourself),
> but I don't know if there is enough status info there to help.

The following -should- work, or at least it does for COX.  Shutdown
the shiny new LTSP server.  Turn off the cable modem, then turn it on
again.  Make sure the only device you have attached is the LTSP server
for which you expect to receive an address via DHCP.  Turn on the
shiny new LTSP server, and the Motorola Surfboard should allow it to
communicate.  Something to do with MAC addresses and stingy ISPs, as
others have mentioned.  The modem "pairs" with a particular MAC addy
(in your case, sounds like the laptop) and simply refuses to talk to
anything else.

HTH,
-dhbarr.