[dns-operations] Signaling client protocol to authority

[Randy Bush]

> to me, having no investment in v4 where i'll see hard costs or lost
> revenue from people who get the v6 transition wrong, it's obvious that
> we should waste no time at all optimizing the mixed v4/v6 case so that
> people who are not ready for v6 won't accidentally be exposed to it.
> 
> to others, whose in-quarter revenue depends on v4 working well until
> the moment it's no longer necessary, many kludges will seem necessary,
> including those which change the protocol for everybody, or which ask
> lots of server-side vendors and operators to behave differently, or
> which make that kludge-like behaviour on the server side will be a
> competitive differentiator.  gack.
> 
> let's go for the gold.  we know where we end up.  let's get there faster
> and spend less time agonizing about the transition.

this was the argument in 1995 and see where ignoring transition has
gotten us today.

you will retire before the need to reach v4-only sites is gone.  i am no
more pleased by this than you.  i just see the world as a bit less black
and white / good and evil.

randy