[TriLUG] ipmasq horrors on switchover to cable modem

[crimsun at fungus.sh.nu]

On Sun, Nov 17, 2002 at 03:44:09PM -0500, Andrew Perrin wrote:
> The cable modem, though, unlike telocity, uses a dynamic IP and so
> requires a DHCP client. FIne, I installed dhcp3-client and tried to get
> the address; I got an alert that CONFIG_PACKET and CONFIG_FILTER had to be
> installed.
> 
> So, I rebuilt the kernel with those flags installed.  Tried again; now I
> got a bunch of DHCPDISCOVER lines, followed by a No DHCPOFFERS received
> line.

Hrm, offhand this sounds like you're either still missing some kernel
config options and/or the dhcp client you're using isn't compatible.
There are a few listed via apt-cache search dhcp|grep client, so you
could try another (some people have better luck with pump or dhcpcd or
dhcp3-client, YMMV). Posting your kernel .config might also be useful...

> Called TWC... they told me how to reset the cable modem so it listened for
> the new MAC address, but the symptom was the same.
> 
> I figured I'd give up for now and go back to telocity. Tried to... and
> couldn't, I think because in the process of rebuilding the kernel I did
> something terrible to my iptables setup.  But I could not figure out what
> I had done wrong.  Finally, I booted to LinuxOLD, which is my old debian
> potato installation, kernel 2.2.19pre17, which runs ipchains instead of
> iptables.   That got me back up, and the network is at least working with
> its old telocity setup.

Hmm...please post your 2.2.19pre17 and 2.4.18 .configs ...

> Interestingly enough, nothing showed up in the logs to suggest packets
> being swallowed by iptables in the newly-attempted setup.

Are you using anything like rinetd with ipchains? These symptoms make it
seem like your iptables ruleset might be a bit _too_ specific for your
new setup (i.e. locking down to an IP address, etc.)...

> Questions:
> 1.) Has anyone got a working earthlink cable modem setup (this uses a
> Terayon TJ615 cable modem) who would be willing to send me their config
> files?

Perhaps there's a firmware update for your particular model? I just
recently went through a similar process with my Westell dual-mode
NAT router (which is a PITA, I might add!), and BellSouth goes out of
their way to obscure the drivers link (which Google found for me).

> 2.) Can someone help me diagnose the iptables problem that killed my
> network on rebuilding the kernel?  I don't even know what files to send.

See above.

-- 
Dan Chen                crimsun at fungus.sh.nu
GPG key: www.unc.edu/~crimsun/pubkey.gpg.asc