Re: [PLUG] Comcast "OPEN IMMEDIATELY" but don't

[gabriel rosenkoetter <gr@eclipsed.net>]

On Sun, Feb 10, 2002 at 12:36:33AM -0500, Michael F. Robbins wrote:
> Assume for a second that they do start filtering by MAC address.  What
> stops me from doing:
> 	/sbin/ifconfig eth0 hw ether 11:22:33:44:55:66

Nothing.

I've a friend--who may be reading this mailing list these
days--that does precisely that on his Linux laptop to use his host
family's cable modem connection which is "bound" in this way to
their Windows PC while he's studying abroad in France.

Note that this fills only the lower 24 bytes of your MAC address,
which is ACTUALLY 48 bytes, though the upper 48 always come as 0s
from the vendor. The old lower 24 bytes are bumped to the upper
24 when you assign the interface a new MAC address. Anyone dumb
enough to think that a MAC address == a host is also dumb enough
to utterly ignore the upper 24 bytes... in fact, every ethernet
hardware I've ever seen ignores them, even fairly brainsy stuff
like Cisco and 3com.

I'm not convinced that this is all Comcast cares about, though. I'd
be unimpressed to learn that their software also sends a keep-alive
signal to some internal server, and your connection drops if that
server doesn't get it. (The hearsay about Netgear having a way to
make the hardware work would probably include having Comcast's
software on a Windows machine inside the router with the Netgear
router modifying the outgoing packet or just having the router reset
the connection at a period shorter than Comcast's keep-alive.)

-- 
gabriel rosenkoetter
gr@eclipsed.net

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