[lug] tcpdump, routing, ppp, and cable modem questions(s)

[Chip Atkinson]

Dang.  Ok.  I'll have to see if I can round up a windows machine for a
little while.

About the DHCP, that is on the cable end of the modem, so I shouldn't have
to worry about that, right?

Thanks for the information too.

Chip

On Mon, 15 Mar 2004, Ferdinand Schmid wrote:

> Chip:
>
> You will need to use Internet Explorer to get to the registration site for
> Comcast.  I have gone through this exercise and found that they really require
> IE.  Also - dhcp in their cable modems doesn't necessarily work with every
> computer.  I had a terrible time with it on my PC - couldn't get it to work on
> a Dell laptop under Linux or Windows.  However, a D-Link router was able to
> talk to it.  Strange...  So my approach to get it working was to use a USB
> cable combined with a Windows PC to do the modem registration.  Until this is
> complete you will only be able to get to your cable modem and to Comcast's DNS
> servers.
>
> So - find a Windows PC to register the modem and then connect your Linux
> system.  If you can't get dhcp working with your particular modem then just
> pick your IP address manually.  The default route (your cable modem's local
> IP) never changes anyway.
>
> Ferdinand
>
> --On Monday, March 15, 2004 08:25:44 AM -0700 Chip Atkinson <chip at rmpg.org>
> wrote:
>
> > Greetings all,
> >
> > I recently signed up for internet access through Comcast, the cable TV
> > provider and am trying to get my machine connected to it.  During the
> > process I came across/caused a couple problems and also can't connect out
> > to anything past the cable modem.
> >
> > Here are the problems:
> > 1) the ppp0 interface has disappeared.  It was working that morning but
> > now is gone.
> > Using kppp I get an error saying
> > ppp: no such interface (don't remember the exact wording)
> > and
> > ifconfig ppp0 up
> > returns ppp0: unknown interface: No such device.
> >
> > 2) I was using tcpdump to watch network traffic on eth0.  When there was
> > no default route set, I saw tons of ARP requests from other machines, but
> > when I set the default route: route add default gw 192.168.100.1 (the
> > cable modem's IP), the ARP request traffic wasn't visible suddenly.  When
> > I deleted the default route, the traffic was visible again.
> > I thought tcpdump grabbed all of the traffic, regardless of routing
> > tables.
> >
> > 3) I'm unable to get to a web server on the Comcast network to register
> > and get to the internet and I fear that it's due to something weird that
> > also caused ppp and the weird tcpdump behavior.  I can ping the WAN end of
> > the cable modem, but nothing else.
> >
> > Does anyone have any similar experiences or ideas?  Right now I'm kind of
> > stumped.
> >
> > Thanks in advance.
> >
> > Chip
> >
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>
>
>
> --
> Ferdinand Schmid
> Architectural Energy Corporation
> Celebrating over 20 Years of Improving Building Energy Performance
> http://www.archenergy.com
>
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