North American Network Operators Group
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Re: Geo location to IP mapping

  • From: Michael.Dillon
  • Date: Tue May 16 05:07:07 2006 
> As a major caveat, all geolocation services do have some degree of
> inaccuracy, because the sources of data are very diverse.  (Some ISPs
> provide complete subnet maps to MaxMind and other providers, whereas
> some data is scraped from WHOIS or provided by inference from
> end-users.)

And some organizations run their own internal networks
across international borders. In other words, knowing
that subnet X is allocated to company Y who has a
300 meg Internet connection in city Z, does not mean
that all the users of that connection are also in 
city Z. They could be scattered around the world.

This is why some companies use other sources of data
to infer the location, i.e. if users of an IP address
prefer yahoo.fr to yahoo.com, then that is one datapoint
in favour of them being located in France. If you 
understand the principles of RBL weighting then you
will get the idea.

--Michael Dillon