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Re: Geo location to IP mapping
- From: Bill Nash
- Date: Mon May 15 19:05:33 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.
On Mon, 15 May 2006, Kevin Day wrote:
We use a Geo/IP location database. It's surprisingly accurate, with a few
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
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.