If admins are setting up their systems to bounce e-mail instead of
simply rejecting it then SPF won't be the spam solution we hoped for.
What kind of sense is that, bouncing an email that SPF says the MAIL
FROM was forged/spoofed to the MAIL FROM address???
The mail has been bounced by an intermediate MTA (not using SPF) because the
final MTA (using SPF) rejected it.
Now the question is if mail that fail the SPF test should be bounced or
discarded. For example if John Smith sends legitimate mail saying
"MAIL FROM:<john(_dot_)smith(_at_)smith(_dot_)com>" through another SMPT
server, then
obviously he should receive the bounced mail informing him that he did
something wrong. But if a spammer sends mail saying
"MAIL FROM:<john(_dot_)smith(_at_)smith(_dot_)com>", then the mail should be
discarded, not
bounced.
Roger