spf-discuss
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RE: Suggest New Mechanism Prefix NUMBER to Accelerate SPF Adoption

2004-08-25 13:38:29
Important additional point below.


Here are the current stats:

SPF result    probability of spam
----------    -------------------
NEUTRAL               0.898679
NEUTRAL(guess)        0.926437
PASS          0.101463
PASS(guess)   0.257572
SOFTFAIL      0.910824
NONE(guessed) 0.658428
UNKNOWN               0.580007
ERROR         too rare to measure


[...]



You just PROVED the risk that large ISPs (AOL, Earthlink, etc) have in 
setting anything but "?all"

You PROVED that they can never set anything but "?all" or "-all" or "+all"/


I think you also showed how "?all" could be misinterpreted mathematically (if 
assumed 0.898679 "probability of forgery" instead of 0.5) and thus it is even 
dangerous for an ISP to set any SPF record.

I realize the stats above are "probability of being spam" not "probability of 
being forgery".  But you were proposing using them as "probability of being 
forgery".