[svlug] using Comcast modem and a Linksys router?

[Lisa]

I had a similar problem when I started with Comcast.  In my
case, and at the time, you had to run a special program on a
windoze box -- they didn't have a linux version of the program
(what a shock) -- which would set up the modem to talk to that
particular MAC address.

I, fortunately, was using a Linksys WRT54G Switch/Router/WAP,
and it has/had an option to (I'll check what it's called now)...
to set a "MAC Address Clone." I turned that feature on, and set
it to the same MAC as the PC that I'd set the modem up with. 
Then I just powered everything off, connected the modem to the
WRT54G, brought everything up and it just worked -- the modem
thought it was still talking directly to the same PC :-)

I assume that your switch/router does not have that capibility,
but if you can, without much difficulty or cost, replace it,
this might be a good option.

Lisa