Matthew> Obviously. The point of NBB is to address this problem.
Matthew> So if it's solved, there's no point. Circular reasoning.
Matthew> The question is why my/another solution is better.
I replied:
Roy> Because NBB will only prevent forged bounces from arriving in
Roy> my mailbox if *everyone* on the Internet implements it (and
Roy> not even then, given upstream bounces).
Or, put another way:
If I implement NBB on *my* MTAs, it does nothing to make *my* life
better, but I make a very small step towards making *everyone else's*
life better. Once when enough people do likewise, my like gets a lot
better.
If I implement one of the bounce discarding schemes, *I* benefit
immediately and substantially. So there's a much stronger incentive
for me to implement.
-roy