Geo location to IP mapping

Kevin Day toasty at
Mon May 15 22:40:23 UTC 2006

On May 15, 2006, at 4:36 PM, Alain Hebert wrote:

>    Yeap,
>    I'm moron.  You didn't know it yet?
> -----
>    Come on...
>   "The way we disperse static IP" ain't imagination, its fact...   
> We spread a /20 on dynamic dialup and dsl over 2 provinces and  
> since most of the residential services is build like this you  
> cannot get a read of where that ip user is located, unless you have  
> also access to our customers db and authentication account db too.
>    The best you'll get is country.  Even then we have some that are  
> LanEx'ed in europe and usa.
>    (FYI: English is not my first language btw...  so dont expect  
> too much)

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  

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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