Re: [Exim] Dnslists lookups not always working

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Autor: Philip Hazel
Data:  
Dla: exim-users@exim.org
CC: Juha Saarinen, Suresh Ramasubramanian
Temat: Re: [Exim] Dnslists lookups not always working
On Fri, 4 Oct 2002, I wrote:

> Yes - the resolver's natural timeout. This results in a "defer" result
> which should give a temporary rejection.


No, it doesn't. I lied. The manual tells you all about it:

   If a DNS lookup times out or otherwise fails to give a decisive answer,
   Exim behaves as if the host is not on the relevant list. This is usually    |
   the required action when "dnslists" is used with "deny" (which is the most  |
   common usage), because it prevents a DNS failure from blocking mail.        |
   However, you can change this behaviour by putting one of the following      |
   special items in the list:                                                  |
                                                                               |
     +include_unknown    behave as if the item is on the list                  |
     +exclude_unknown    behave as if the item is not on the list (default)    |
     +defer_unknown      give a temporary error                                |
                                                                               |
   Each of these applies to any subsequent items on the list. For example:     |
                                                                               |
     deny dnslists = +defer_unknown : foo.bar.example                          |



Lucky you brought this to my attention. I had neglected to update the
forthcoming book to include this information. It now has it.

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