phone fun, was GeoIP database issues and the real world consequences

Owen DeLong owen at
Wed Apr 13 19:25:23 UTC 2016

> On Apr 13, 2016, at 12:15 , John Levine <johnl at> wrote:
>>> 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 place.
>> I was careful to pick a number on a Canadian company's website.
> Doesn't matter.  In the NANP, toll free 8xx numbers are routed by
> carrier, not by geography, and it looks like this company handles
> traffic in the US, too.  It's entirely possible that when you call
> that number during the day you get someone in Toronto, and when you
> call it at night, you get an answering service in the Phillipines.
>>> 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
>> guess.
> Really, they're not assigned to locations, they're assigned to
> carriers.  They can even be assigned to different carriers in
> different countries although that's not common.
> More to the point, saying "somewhere in the US", even if it's
> occasionally wrong, will not send nitwits with guns to a particular
> location.  NANP geographical numbers can be located to a switch (give
> or take number portability within a LATA), but non-geographic numbers
> can really go anywhere.  On the third hand, it's still true that the
> large majority of them are in the U.S.

Would you agree that 408-921 is a geographic number?

I guarantee you that there are phones within that prefix within US/Calif/LATA-1 and also some well outside of that, probably not even in the same country.

I will also guarantee you that those phones move locations quite frequently.


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