Re: [exim] Does exim cache a failure of: $sender_host_name

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Author: Philip Hazel
Date:  
To: Martin Nicholas
CC: Exim Users
Subject: Re: [exim] Does exim cache a failure of: $sender_host_name
On Mon, 6 Dec 2004, Martin Nicholas wrote:

> It seems not, but I thought I'd ask.
>
> On V4.34 a lot of time seems to be spent repeatedly asking for the rDNS.


Exim assumes that name servers have efficient caches of DNS data, so it
does not need to cache it for itself. A busy mail server should have
access to a nearby caching name server, possibly even a private one just
for its own use.

Besides, Exim is not a long-running process. Anything it caches between
processes has to be on disk, which isn't as efficient.

-- 
Philip Hazel            University of Cambridge Computing Service,
ph10@???      Cambridge, England. Phone: +44 1223 334714.
Get the Exim 4 book:    http://www.uit.co.uk/exim-book