Re: [exim] whitelist geographical location

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Lähettäjä: Ian Eiloart
Päiväys:  
Vastaanottaja: Martin A. Brooks
Kopio: exim-users, palmeida
Aihe: Re: [exim] whitelist geographical location


--On 14 April 2008 14:09:29 +0100 "Martin A. Brooks"
<martin@???> wrote:

> Ian Eiloart wrote:
>> I don't think you'll get much more precise information than the country,
>> either. For example, I'm in Sussex, but my home ISP is in Yorkshire, so
>> (even if I used their email service), you'd not know much about my
>> location.
>>
>
> You can by purchasing an appropriate licence from, amongst others,
> MaxMind ( http://www.maxmind.com/app/ip-location ). This can give you
> quite granular, and quite accurate location information.


"Granular"? Yes. "Accurate"? No.

For example, I have a fixed IP address provided by my ISP. I'm in Sussex,
and my IP address is listed in Derby - 200 miles away.

OK, that's close by US standards, but by the time I get to Derby, I'm half
way from the south coast of England to Scotland. If I'd travelled east for
the same distance, I'd have crossed the English Channel, part of France and
half of Belgium.

A 200 mile error in most European countries means that you can't even tell
which half of the country you're in. The situation is worse, though. It's
quite possible that all Plusnet customers appear to be in Derby, whatever
part of the UK they're really in.

Here are the apparent locations of the six local authorities in East Sussex:
East Sussex County Council: Oxfordshire, 100 miles away
Lewes District: West Sussex (close, but a different county)
Hastings: Lennoxtown, East Dunbartonshire, Scotland
Eastbourne: Eastbourne!
Wealden: Eastbourne, or Brighton
Rother: Bexhill (actually in Wealden district)

So, some are close, but far enough away to confuse. Hastings, though, is
misplaced by almost 500 miles, and arguably not even in the right country!
In fact, that same displacement in a different direction could take you to
any of 11 different European countries, even if you don't count Scotland.
--
Ian Eiloart
IT Services, University of Sussex
x3148