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Re: I-D SMTP Extension for Greylisting

2011-10-25 13:44:24

Frank Ellermann wrote:
On 24 October 2011 16:36, Hector wrote:

� seconds � � = 2DIGIT � ; 00-59
� totalsecs � = 1*(%d48-57) ; total seconds to delay

If this suggestion for a 2nd syntax format is
acceptable, is the ABNF correct?

Ignoring the premise, you can use 1*DIGIT instead of
those decimal constructs ;-)  If you want to specify
<totalsecs> details you could suppress leading zeros
and add an upper limit -- the very odd 99-23:59:59
maximum yields 1*7DIGIT if I got this right, please
check it if you want to use it.

And trim this to 1*6DIGIT if they let you, IMO 9 days
is already far outside of anything remotely related
to SMTP.

I am personally liking more and more Claus Assmann's suggestion of using a MIN/MAX concept and to keep it simple a syntax of:


with the ABNF:

   retrytime  = "retry=" min-secs ["-" max-secs]

   min-secs   = 1*digits   ; minimum blocking time
   max-secs   = 1*digits   ; optional retry expiration time

The parsing is simple, no technical limits (only policy based) and it can help adoption by operators who can just simply change the response language resource files/configuration and don't need to wait for developers to alter their greylisting code to calculate a [DD-]HH:MM:SS format.

I think I will add it and see how it flies.