From: Rich Graves <rich@c2.org>
Date: Wed, 14 Aug 1996 09:51:01 +0800
To: cypherpunks@toad.com
Subject: Re: [NOISE] Geek Apartments
In-Reply-To: <9608131541.AA26416@sso-austin.sps.mot.com>
Message-ID: <Pine.GUL.3.95.960813140118.5632A-100000@Networking.Stanford.EDU>
MIME-Version: 1.0
Content-Type: text/plain


On Tue, 13 Aug 1996, Ben Combee wrote:

> Yes, it has already happened, although in a slightly different
> context.  The Georgia Tech campus dormatories got wired with Ethernet
> back in 1994, and there was quite a rush by the sizable geek

The graduate residences at Stanford were built with 10Base2 in 1986, and 50%
of the undergrad dorms were wired with 10BaseT by 1993. So there.

> population to get dorm rooms in the buildings slated to get
> installation first.  It worked out quite well, especially the privacy
> aspects, as the dorm routers encrypted all packets so only the
> intended Ethernet node could receive it (at least that is what they
> said).  

The "secure hubs" at GATech don't do encryption -- no way could that be done
at wire speed. What they do is fill the data portion of the Ethernet packet
with nulls. Everyone gets to see the source and destination MAC address and
length of every packet, but only the recipient (or a very clever spoofer --
most of the "secure hubs" on the market have a few vulnerabilities) gets
the data.

If you run a packet sniffer, all you get are CRC errors (in order to
maintain wire speed, the non-destination ports don't compute one). 

As far as real-world geek apartments go, I heard of one in Manhattan that
worked exactly as described. I don't know whether they run "secure hubs."
Presumably they would -- I can't think of a major manufacturer's manageable
10BaseT hub that lacks MAC address lockout features.

OTOH, I've heard tell that several of the residential coax experiments run
promiscuously. Everything your neighbor does online, you can see with the
right software.

-rich