Re: [Exim] Reverse lookups

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Autor: Philip Hazel
Datum:  
To: Paul Walsh
CC: Exim Users
Betreff: Re: [Exim] Reverse lookups
On Tue, 31 Aug 1999, Paul Walsh wrote:

> Question is, if nslookup can get sand.global.net.uk from 195.147.248.109,
> why doesn't Exim, or rather, why does Exim fail the lookup? Is it because
> the IP address returned by the forward lookup doesn't match the one exim
> see's the connection coming from?


Yes, and in many systems it isn't Exim that fails the lookup, it is the
gethostbyaddr() function (which Exim calls) that does the check. Exim
does in fact also check, just in case.

The point is that the forward and reverse DNS zones are entirely
distinct. The owner of the 195.147.248.109 entry may have nothing
whatsoever to do with sand.global.net.uk, and may have put that entry
there as a bit of wickedness.

-- 
Philip Hazel            University of Cambridge Computing Service,
ph10@???      Cambridge, England. Phone: +44 1223 334714.