Zitat von David Brodbeck <gull(_at_)gull(_dot_)us>:
And greylisting can be a problem as well. There are some broken mail
systems (sending legitimate mail) which treat the greylister's
"temporary failure, please try later" as a delivery acceptance and
never resend. Nor do they (or the particular one I have encountered)
give a non-delivery report to the sender.
I would guess that the people who object to CBV will also object to
greylisting. It's yet another form of cost-shifting -- you're forcing the
sending server to keep the message on its queue longer and make more
attempts to try to send it.
With greylisting the cost remain between the two parties involved in the mail
transaction (sendr/recipient). With CBV some third, maybe not at all related
part have to "pay" too for the transaction.
That is a great difference if you think of a virus attack with forged sender
addresses.
Regards
Andreas