On Wed, 16 Jan 2008, Mark Andrews wrote:
Since when has Informational been equivalent to Standard?
Since (a) there is no standards-track specification to override it, and
(b) all implementations follow RFC 3974, and (c) it's the obvious
extension of v4 behaviour to v6. I should have said in my previous
message that not only do the most popular MTAs fall back to AAAA, but BIND
also includes AAAA in the additional section of MX replies, which
re-inforces the RFC 3974 interpretation.
a) when RFC 2821 was written IPv6 existed and RFC 2821 acknowledged
its existance. It did DID NOT say synthesize from AAAA.
c) MX replies is *not* MX synthesis.
Do you really thing we should be trying to force a upgrade
of all MTA's on the planet to support MX synthesis from
AAAA when there is no engineering need to to this?
They have already been upgraded in this way. Even without fallback-to-
AAAA, they have to be upgraded to handle IPv6 anyway, because the IPv4
MX lookup algorithm breaks as I described in
http://www1.ietf.org/mail-archive/web/ietf/current/msg49843.html
MX additional section is a optimization. The lack of AAAA or
A records is NOT a bug.
MX from A was a transition strategy.
It might have been intended that way, but it has become a permanent part
of the protocol.
And it has negative impacts on DNS caches and MTAs.
There is no need to use the same kludge with IPv6.
Tony.
--
f.a.n.finch <dot(_at_)dotat(_dot_)at> http://dotat.at/
WEST FAIR ISLE FAEROES: NORTHEASTERLY VEERING SOUTHEASTERLY 5 TO 7, PERHAPS
GALE 8 LATER. VERY ROUGH. SHOWERS. MAINLY GOOD.
--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: Mark_Andrews(_at_)isc(_dot_)org
_______________________________________________
Ietf mailing list
Ietf(_at_)ietf(_dot_)org
https://www1.ietf.org/mailman/listinfo/ietf