ietf-smtp
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Re: We need an IETF BCP for GREY LISTING

2011-10-17 12:50:25

Hector wrote:
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.

--
HLS