DHCP setup problems

[dougsweetser at gmail.com (Doug)]

Hello Ward:

> Is Comcast one of those fascist ISP's that limits the (number of) devices
> that can connect to the cablemodem to a whilelist of mac addresses?

That was an interesting possibility.  So I took a close look at my
telephone/broadband box.  The modem does not have an off switch,
because a phone service is always suppose to be on.  It does have a
"Standby" button.  I turned all my computers off, then hit the standby
button.  I powered up the laptop.  When I ran ifconfig, I got these
three lines:

eth0   Link encap:Ethernet HWaddess ...
         inet addr:192.168.100.2   Bcast...
         inet6 addr: ....

I was unable to browse the Internet.

I powered up the good box, it gave a similar address:

eth0   Link encap:Ethernet HWaddess ...
         inet addr:192.168.100.3   Bcast...
         inet6 addr: ....

The good box could no longer browse the Internet.  Each machine could
ping the other.  So I hit the Standby button, and run ifconfig

Laptop:
eth0   Link encap:Ethernet HWaddess ...
         inet6 addr: ....

Big box
eth0   Link encap:Ethernet HWaddess ...
         inet addr:24.91.111.170   Bcast...
         inet6 addr: ....

The laptop could not browse the Internet, nor ping 24.91.111.170.

It looks like the comcast modem has a special bond now for the
ethernet card on the big box.  I guessing a bit here, but I would
think I have to put in another ethernet card on that box, then make it
a DNS server for the other boxes, give those other boxes static IPs,
and then make sure the big box is always on if the other computers
wish to do any networking.

doug