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Re: draft-kucherawy-greylisting-bcp

2011-10-26 12:48:23

Keith Moore wrote:
One 'interesting' aspect of an interop test for greylisting is that it would 
only affect servers.  Greylisting is supposed to be backward compatible with 
standards-conforming clients.   What you would want to establish via 
interoperability testing is that a server that implements greylisting per the 
RFC doesn't degrade interoperability with existing, properly-implemented, 

I don't have a strong opinion of BCP vs. standards-track for this.  I think 
that if it's desirable to publish an RFC on this topic (which I doubt), either 
BCP or PS would suffice.   But I do think that if it's going to be published as 
PS, the document needs to define testing criteria for advancement.

The only factor I see that can come close to degrade testing idea:

  - a compliant MTA does retry per SMTP,  but
  - before the Greylisting blocking time.

A key issue, if you need a reminder is the blind MTA world of varying degrees in blocking times and this is why we need a mechanical client/server automaton as oppose to a BCP which will end up being most likely a subjective "Rough Concensus" of the stronger IETF keys and participants making a "Best for all world" compromise offering of TIME that will not resolve the central issue:

    BCP TIME < GL Blocking Time => wasted attempts
    BCP TIME > GL Blocking Time => Delayed deliveries.

This has long been measured and of recent measure with internal testing of the proposal showing the proof of concept has been a 100% success in achieving a minimum of 2 attempts at precisely the delay time the server suggested.