Using RIR info to determine geographic location...

Marshall Eubanks tme at
Mon Dec 24 13:50:19 UTC 2007

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

> On Dec 20, 2007 8:13 PM, Greg Skinner <gds at> 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

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