[ On Wed, April 15, 1998 at 10:24:17 (+0100), Christopher Purnell wrote: ]
> Subject: Re: [EXIM] DNS
>
> Why is everyone misunderstanding me here? The order MX,A might be
> what is done for the original domain but A,MX is the order for
> unresolved targets of an MX lookup.
In the case where ther *is* an MX, albiet a broken one, you *cannot* try
to deliver to the 'A' for the same host. Without knowing what's
"broken" about it, it's impossible to determine if sending to the A
that's adjacent to the MX is correct, or not.
For example say I have:
myhost IN A 10.0.0.2
myhost IN MX 5 corp.mail.gw
and
corp.mail.gw IN A 10.0.1.200
*and* my network is filtered behind a firewall such that the *only* way
to get mail into my network is the 10.0.1.200 address. In this case if
I've made a mistake in specifying the MX for "myhost", then attempting
delivery to the A for "myhost" is not only wrong, it just won't work.
There can be even more tangled structures possible too, and it is
literaly *impossible* for a piece of software to determine what's
correct in the face of such an error. In fact in the general case it is
impossible for anyone except the administrator of the zone in question
to know exactly what's correct.
--
Greg A. Woods
+1 416 443-1734 VE3TCP <gwoods@???> <robohack!woods>
Planix, Inc. <woods@???>; Secrets of the Weird <woods@???>
--
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