Using RIR info to determine geographic location...

Greg Skinner gds at
Fri Dec 21 04:32:20 UTC 2007

On Thu, Dec 20, 2007 at 10:17:36PM -0500, Steven M. Bellovin wrote:
> On Fri, 21 Dec 2007 02:13:17 +0000, Greg Skinner <gds at> wrote:
> > Personally, I have trouble accepting some of the claims the
> > geotargeting companies have made, such as Quova's 99.9% to the country
> > level, and 95% to the US state level.  ( More info at
> > ) Perhaps I'm just part of the
> > outlying data; using the "three top search engines" I rarely see them
> > get the city correct (ie. where *I* am physically located, as opposed
> > to where the registration data says the block is located), and have
> > seen some glaring errors for the country in some cases.
> > 
> > Geotargeting has turned into quite a business, and I'm concerned that
> > people who rely on these services do not fully understand the risks.
> > 
> Some folks are relying on it for serious purposes.  Many Internet
> gambling sites use it to avoid serving US customers, for example.
> Their risk is criminal liability for the executive -- the have a
> strong incentive to get reliable data...  Some sports media sites use it
> to enforce local area blackouts; though that doesn't need to be
> perfect, if it's too imperfect they risk breach of contract and
> expensive lawsuits.
> For the advertisers, best effort is probably good enough...
> 		--Steve Bellovin,

Funny you should mention sports media sites.  Not too long ago,
someone asked on usenet how to foil geotargeting in order to watch a
sportscast that was being blocked.  The answer was posted not long
after the question.  It doesn't surprise me that "the word is out" on
how to foil geotargeting, but it disturbs me that this aspect of
geotargeting is not discussed more.  I would prefer it if there were more
openness and transparency about such things (without necessarily
divulging the exact means by which geotargeting can be foiled).

The Carleton paper ( )
goes into some detail on the practical limits of geotargeting, but it
has been difficult to raise this type of awareness among consumers of
geotargeting services.

WRT advertisers, opinions are mixed on whether best effort is good
enough, fraud aside.  Some feel any discrepancies are just a cost of
doing business on the Internet; hopefully they have factored
discrepancies into their ad spend.  Others are more skeptical.  Some
of you may find ( )


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