Re: [exim] hostlist +ignore_defer feature request

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Author: Philip Hazel
Date:  
To: Exim Mailing List
Subject: Re: [exim] hostlist +ignore_defer feature request
On Wed, 20 Jun 2007, Dean Brooks wrote:

> Here's the feature request. If I put in a hostname (instead of IP
> address), Exim will stop processing the entire hostlist file if it
> fails to look up a single hostname in that file due to a temporary DNS
> lookup failure. This can happen if the remote DNS servers are
> misconfigured (i.e. lame delegations) or if the remote site is having
> problems.
>
> Thing is, for a whitelist, I don't really care, and would prefer to
> be able to add:
>
>    +ignore_defer

>
> or something around the host names in that file.


You may be able to do this already, by putting +ignore_unknown into your
hostlist, and also setting

dns_again_means_nonexist = hostname1 : hostname2 : ...

I have not tried this, but I think it should work, and of course you
could use a macro to avoid specifying the same hosts twice.

I agree, though, that something like +ignore_defer and +include_defer
would be tidier (and easier to document).

> Perhaps it should be called +ignore_again to match DNS terminology, or
> +ignore_errors to indicate its ignoring *all* dns errors, rather than
> just permanent failures.


I would rather keep it separate from the "unknown" ones so that you have
the choice of treating them differently.

-- 
Philip Hazel            University of Cambridge Computing Service
Get the Exim 4 book:    http://www.uit.co.uk/exim-book