North American Network Operators Group

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Re: Using RIR info to determine geographic location...

  • From: Marshall Eubanks
  • Date: Mon Dec 24 08:55:13 2007

On Dec 24, 2007, at 1:23 AM, James Hess wrote:

On Dec 20, 2007 8:13 PM, Greg Skinner <[email protected]> wrote:

Personally, I have trouble accepting some of the claims the
geotargeting companies have made, such as Quova's 99.9% to the country
level, and 95% to the US state level. ( More info at ) Perhaps I'm just part of the

The trouble with a claim of "95%" accuracy is the method of
determining the accuracy
of the measurement has not been indicated, and there are _many_ IPs out there.
With no method of obtaining the statistic indicated: there is no evidence I saw
that 99%/95%, weren't possibly just made up numbers for the purpose of
aggressively marketing a product.

Well, I use a geolocation service, and as I travel around to many fine hotels and meetings,
I try to check frequently to see if it knows where I am, so I have a few dozen test probes scattered about the globe.

The results are mixed. On US corporate (enterprise) networks, it is typically unreliable. In-room
hotel networks generally get mapped to the right city. Wireless hot spots are erratic - sometimes mapped
to better than a km, sometimes wildly off. People's home networks, generally the right country, frequently the right city.

I would say, overall

- mapping to the right country, probably better than 95% accuracy, maybe 99%.
- mapping to the right city, at least 75% of the time, for sure not 99%, even if you discount enterprise networks.

Of course, your probable error may vary...


I agree it is not very believable that a geolocation service properly locates 95% of all ip addresses to within a state/city.

Due to the existence of various types of proxies and anonymizer services,
visible IP often does not reveal original requestor details.

RIR records give contact information for an organization utilizing IP
space, that's
not the same as the physical location of nodes -- it makes the RIR data an
unreliable source of information for that usage.

This information is not necessarily always up to date in the first place.
Nodes on the very same RIR allocation may be geographically distant.

No more reliable than performing traceroutes to the destination IP,
reverse resolving,  and
using pattern matching to search for  possible city, state, country
names contained in
the reverse DNS mappings of the hops nearest the target.

(Since providers sometimes include state and/or city names in router rDNS hosts)

On the other hand, it's perhaps the best geolocators can _try_ to do...

Short of geolocation services manually calling ISPs and asking.../
making deals with major ISPs to procure lists of geographic regions and
assigned IPs in those regions.

I suppose that in theory proper geolocation close to 95% of IPs for page access
requests would occur then (provided 95% of page access requests came from
providers they had that type of direct information from)

-- -J