--On Thursday, 27 March, 2008 12:31 -0700 "Hallam-Baker, Phillip" <pbaker@xxxxxxxxxxxx> wrote: > The key issue here is whether people who rely on AAAA are > likely to achieve their desired result. Today it does not > matter because anyone who relies on AAAA alone with no A > fallback is going to receive almost no mail. Phillip, This is true iff you believe that there are too few IPv6-enabled mail senders to transmit such mail. It ultimately has nothing to do with whether there are MX records present, since having an explicit MX record that pointed to a mail exchanger host that only had a AAAA record would leave the sender in exactly the same situation -- deliver over IPv6 or don't deliver at all. That parallelism moves the discussion entirely out of the scope of whether the text in rfc2821bis is correct or not. More important, I suspect that belief is false. Installations who run IPv6-only generally know their correspondents. The correspondent would presumably need to be running dual-stack, or have a submission server or equivalent that is running dual-stack (or IPv6 only as well), but, in many parts of the world, those are not rare. A statement I believe would be true is that a mail server that only supported incoming connections over IPv6 would receive almost no spam, at least until IPv6 becomes much more popular. But, the last I heard, that would usually be considered an advantage. john _______________________________________________ IETF mailing list IETF@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf