On 8/24/2016 8:41 AM, John C Klensin wrote:
IMO, 5321 really should have said
is that am implementation utilizing, rather than refusing to
follow, such a MX -> CNAME -> <something> set of DNS entries was
not conforming to the standard and that anyone who did it anyway
needed to be extra careful to be sure they didn't get tangled up
in DNS entry loops (e.g., MX -> CNAME1 -> CNAME2 -> CNAME1) or
other weirdnesses (e.g., MX1 -> CNAME1 -> MX2 -> ???) and to
have good diagnostics if they did.
I've been noting some tendency for specs to try to make substantive
statements about behaviors that are out of scope.
A spec needs to be explicit about 'interesting' behaviors that are out
of scope. It might benefit from explaining why it is out of scope.
What it should /not/ do is make any substantive statements or statements
that imply substance -- such as guidance to be careful (whatever that
means) -- since that effectively makes the topic /in/ scope.
d/
--
Dave Crocker
Brandenburg InternetWorking
bbiw.net
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