spf-discuss
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Re: Eric Allman comments on SPF

2003-12-04 02:52:10
Marc wrote:

Is there a situation where a domain owner would NOT want the MX's to be
authorized to send mail on behalf of his domain? What I'm getting at is a
'default' rule that would, in effect, eliminate the MX directive, such
that MX's would be assumed to be authorized to send on behalf
of the domain.

What difference does that make? All that does, is tell people they have no
need to publish their MX directive; but the MX query has to be made
regardless. Sure, the protocol, for instance, could assume mx, unless -mx is
published. Same difference; it still means the default is to do a MX query.

Personally, I would have loved to see an even more fine-grained extension to
the protocol, like mx1 and mx2 directives, for instances, where mx defaults
to mx1 + mx2. But, hey. :)

Meng wrote:

John Levine criticized the first version of RMX, saying that major
domains like Yahoo would never be able to fit all their networks into
512 bytes. Indeed, pobox.com is hardly a huge ISP, and our MX servers
span seven or eight distinct networks.

And I wholeheartedly concur.

I can certainly add a recommendation that domain publishers
precompile their records into ip4 notation to save overhead.

That sounds nice, 'precompile'. But what it really means, is that a large
ISP like Yahoo will have to be excessively exhaustive in finding and
publishing all the IP addresses of all its possible MX servers; and I bet
they be many. Not to mention, that, from the publisher's point of view,
keeping all records up-to-date is a veritable nightmare.

Besides, if you give in to having people precompile their records into ip4
notation, then you have effectively killed the mx, ptr, a, etc.
functonality.

- Mark

        System Administrator Asarian-host.org

---
"If you were supposed to understand it,
we wouldn't call it code." - FedEx

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