Keith Moore wrote:
Personally I think writing up an RFC on greylisting will only dilute
its effectiveness as a spam countermeasure.
I don't agree with this concern.
So I see no negatives at all here.
BTW, Keith, many GL servers already have responses with hints. From my
logs, I have collected these varying responses with hints:
421 This server implements greylisting, please try again in # seconds
450 4.7.1 <RCPT>: Recipient address rejected: Greylisted for # minutes
450 4.7.1 <RCPT>: Recipient address rejected: Greylisted for # seconds
451 4.7.1 Greylisting in action, please come back in HH:MM:SS
451 Greylisted for # seconds
451 Greylisted, please try again in # seconds
451 Greylisting enabled, try again in # minutes
I don't know of a current client MTA that leverages this yet for
rescheduling, but I plan to explore parsing these responses to apply
to rescheduling to see how that improves thing (it expect it will).
One goal would be to formalize this response.