Mark Andrews wrote: > It was more "the only way to prevent the A lookups is > to remove the fallback".
> If we ever head down this path there would need to be > years of advance notice. My € 0,02: There is no direct way to get rid of the old A-fallback, 2821bis can say "please" in a note, maybe an additional BCP could go as far as SHOULD, and that is it. Indirectly the great master plan AFAIK is that IPv4 will die, and without IPv4 the A-fallback also dies. So what we now have to decide is if we want an AAAA-fallback for IPv6, or if we have a chance to kill this AAAA-fallback. Any "mail opt-out" alternatives like "v=spf1 -all" or the nullmx draft are odd if the great master plan is to have names and IPv6 addresses for "everything", notably billions of things never intending to send or receive mail. A "mail opt-in" for IPv6, where only names with an MX are interested in mail, would be more straight forward. The "opt-out" alternatives can play a role while IPv4 still exists. But they would be an ugly kludge for the brave new IPv6 world. Frank
