Re: [Exim] DNSBL Question/Alert

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Author: Philip Hazel
Date:  
To: James P. Roberts
CC: exim-users
Subject: Re: [Exim] DNSBL Question/Alert
On Wed, 8 Jan 2003, James P. Roberts wrote:

> is there any simple way to do something in the code, to achieve the
> following:
>
> (a) if we get some number of timeouts in a row, to a particular DNSBL,
> temporarily stop using that DNSBL.


No. Difficult to define "in a row". This is because Exim is not a
centrally controlled application; independent processes are not
coordinated. (I'm giving a talk about this in Sweden next month,
pointing out what you gain and lose by such "anarchy".)

To do what you want would require Exim to write a hints record for every
timeout, and to read a hints record before attempting the next DNSBL. I
guess this wouldn't impact too much, because it would be mostly reading,
which does not require exclusive access to the file.

WishListed.

> Another idea balloon to float:
>
> If using +defer_unknowns with one's DNSBL list, and if only one of
> multiple DNSBL is giving timeouts, and the other(s) are giving a clean
> bill of health, do not impose the defer.


WishListed.

<smallprint>
"WishListed" means I've put the idea on the list for thinking about in
the future. What gets implemented (if anything) may not be exactly what
is suggested.
</smallprint>

Philip

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