North American Network Operators Group|
Date Prev | Date Next |
Date Index |
Thread Index |
Author Index |
Re: Geo location to IP mapping
- From: Alain Hebert
- Date: Mon May 15 19:11:51 2006
(In a more precise manner)
I originaly stated that below country (aka, province/state, city,
zip, etc) it wont be very reliable because in my experience we spread
that /20 without the hierarchy you expect.
. We have subnets on LanEx going outside the city, province/state
and even country;
. We concentrate compagny with 10 to 50 sites using private ip and a
single internet point;
. We have dynamic ip users using cable, dsl, dialup and even
I'm sure peoples have many more of hierarchy situation like this one.
None really, short of having access the real infrastruture of the ISP.
I'm sure the IP Location Industry have deals with the major ISP to
get their DB more precise.
But if the targeted IP is on a smaller outfit the quality of the
informations will not be the same. This is why I stated that globally
the state/city should be pretty low (50%).
That good that you have 75% to 85% but I wasn't ignoring the AOL's
in my statement.
(FYI: The NTP Issue has been resolved (;-} )
Kevin Day wrote:
On May 15, 2006, at 4:36 PM, Alain Hebert wrote:
We use a Geo/IP location database. It's surprisingly accurate, with a
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.
Alain Hebert email@example.com
P.O. Box 175 Beaconsfield, Quebec H9W 5T7
tel 514-990-5911 http://www.pubnix.net fax 514-990-9443