While it might not help significantly, something more generic
would at least slightly and temporarily lower the odds of a
different problem.
A generic solution would also mean that we don't have to design the same
solution multiple times for different applications. A few cases were
brought up earlier such as if a site needs to be unavailable for a
pre-determined period of time (site maintenance, etc). I'm sure with some
thought we'd be able to come up with more, and as time goes on, additional
applications will probably also find this of use.
I really worry about saying to the spammer
"this site does greylisting" and, if that happens enough, having
the spammer respond (internally) "ah, it is greylisting and not
some random temporary server unavailability, we know what to do
about that".
Another good reason NOT to tie it in with greylisting. In fact, my
preference is to never use it for greylisting for precisely the reasons you
cite above. But admins on other sites may feel differently - so for those
that choose to reply in such a manner, it would be nice if the format was
standardized.
Independent of what advantages it offers people who are trying
to cooperate in sending legitimate mail, to paraphrase Paul
Vixie, giving spammers the information they need to become
smarter and the incentives to do so are really not in our
long-term best interests.
I have other doubts about both proposals but, if we are going to
move forward with either, I think we need to understand and
consider the tradeoffs very carefully.
Absolutely! As well as any potential abuse scenarios that could be
utilized.
Best Regards,
-- Tim