DHCP issue with comcast (FreeBSD router).

Gary W. Swearingen underway at comcast.net
Tue Mar 9 10:42:08 PST 2004


"Richard Uhlman" <ruhlman at comcast.net> writes:

> I am new to using FreeBSD, and I am trying to use a FreeBSD box as a
> firewall/router. I am trying to get the router working correctly first.

I won't try to tell you how to fix your problem, but I'll tell you
what works for me on COMCAST cable with FreeBSD.  Maybe it'll give
you some ideas.

FIREWALL/BRIDGE:

I got a junker 486/66 (16 or 20 MB) with no hard disk and put two ISA
NICs in it.  On my desktop FreeBSD, I read the "picobsd" manpage and
built a picobsd firewall+bridge floppy and use it to boot the 486.
The system goes between the cable modem and acts like a cable, with
no IP config, etc.  It shouldn't be real hard to make a router
version, but the bridge version avoids problems with DHCP, NAT, etc.

DESKTOP:

On my desktop, I wrote a Python program hooked into a fvwm2 button
to control and monitor my online status.  It uses:

ifcommand = "/sbin/ifconfig de0 "
upcommand = "/sbin/dhclient de0"
downcommand = ifcommand + "down delete; kill `cat /var/run/dhclient.pid`"

I think I've conneted from a console using just: /sbin/dhclient de0

The only thing in my /etc/rc.conf is to turn on the desktop's firewall.  

You might review your kernel config.  And list your current firewall
settings (ipfw -show) to ensure it's OK.

I did not not have to give my MAC to COMCAST, but they might or might
not have locked in on the first one they found; I've never switched.


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