North American Network Operators Group|
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Re: Geo location to IP mapping
On May 15, 2006, at 4:36 PM, Alain Hebert 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.