Geo location to IP mapping

Bill Nash billn at
Mon May 15 23:02:44 UTC 2006

Google's available geolocation resources are much more direct: They can 
get the information directly from the user. Google mail users setting 
location information, google home page users setting weatherbug details, 
common location searches in google maps, or local business directory 
searches. Taken in connection with neighboring IPs, you can generate the 
correlations statistically, even going so far as being able to make a good 
guess at a dialup IP versus an 'always on' connection.

This would be the same for MSN, Yahoo search, or any portal based search 

Forget relying on a thousand different companies hopefully keeping 
accurate records, *if any* about what IP where. The user is, for once, a 
much better source of information.

- billn

On Mon, 15 May 2006, Kevin Day wrote:

> We use a Geo/IP location database. It's surprisingly accurate, with a few 
> exceptions.
> The company we purchased the database from uses a number of sources of data, 
> to produce something pretty accurate:
> 1) WHOIS records for the IP assignment
> 2) WHOIS records for domain in the PTR record for the IP
> 3) Parsing the PTR record for city names and airport codes
> 4) Purchasing IP/billing and shipping city,state,zip records from sites with 
> accurate records (e-commerce and other sites that people need to enter their 
> local info)
> 5) All of the above for the hop or two before the end in a traceroute
> 6) BGP and traceroute comparisons to determine where the boundaries are in 
> how you've internally routed things
> Even if you're just allocating from a single /20, you probably have some 
> hierarchy,  and that can be picked up through routing or DNS or SWIP.
> Comparing the database to the IP that our customers used to make purchases we 
> exceed 95% accuracy in identifying the country, and 75-85% in city/state. The 
> big exception is AOL, since their IP assignments are pretty well randomized 
> with respect to geography.
> Never underestimate what can be done through regular expressions and an army 
> of people sitting at terminals in China to verify what can't be automated. :)
> For those of you really interested, email me privately and i'll dump what we 
> have on record for a block or two of yours.

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