Re: [exim] Exim4 & IPV4

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Author: Philip Hazel
Date:  
To: exim-users
Subject: Re: [exim] Exim4 & IPV4
On Tue, 29 Nov 2005, Marc Sherman wrote:

> >> dns_ipv4_lookup = *
> >
> > If you do this
> >
> >> and
> >>
> >> ignore_target_hosts = ... : ::::/0
> >
> > do you still benefit from doing this?
>
> Sadly, yes.
>
> http://www.exim.org/mail-archives/exim-users/Week-of-Mon-20050613/msg00049.html
>
> IMO, that's a bug.



Why do you think that it is it a bug? As far as I know, it operates
exactly as documented: dns_ipv4_lookup says "don't ask nameservers for
AAAA records for these domains". It exists because some nameservers go
doolally if you do. That is all that it does. Exim may acquire AAAA
records from other domains, or because a nameserver gives them "for
free" with MX records.

If, on the other hand, you think it's a design error, then, well, yes,
it's a hack, and most hacks are in some sense "design errors". Of
course, the hard-line approach is "If you don't want IPv6 facilities,
why are you running an Exim binary that was compiled with IPv6 support?"
But, sigh, I can see why people get into that situation...


-- 
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