GeoIP database issues and the real world consequences

David Cantrell david at
Wed Apr 13 16:39:19 UTC 2016

On Wed, Apr 13, 2016 at 03:31:47PM -0000, John Levine wrote:
> >There are similar problems with phone numbers. Google's libphonenumber,
> >for example, will tell you that +1 855 266 7269 is in the US. It's not,
> >it's Canadian ...
> Actually, it's probably both US and Canadian.  When you call an 8xx
> toll free number, the switch uses a database to route the call to
> whatever carrier handles it, who can then do whatever they want.  The
> provider for that number, Callture, is in Ontario but they can
> terminate the calls anywhere, and send each call to a different lace.

I was careful to pick a number on a Canadian company's website.

> Also, in fairness, the US is about 90% of the NANP, so guessing that
> an 8XX number is in the US is usually correct.

That's another way of saying that it's deliberately wrong 10% of the
time for pan-NANP prefixes. Better to say "I don't know" than to just

David Cantrell | Official London Perl Mongers Bad Influence

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