[ietf-dkim] Modified Introduction text for rfc4871-errata (resend)

[Michael Thomas]

Murray S. Kucherawy wrote:
>> DKIM's purpose has been lost with the continued  out of scope undefined
>> reputation modeling. A concern raised over and over again, Assessment |
>> Reputation - wink wink, same thing when it come to coding it.  Word
>> smithing does not solve implementation issues.
> 
> I don't agree at all with these claims.  An assessor module can make a complete determination about what to do with a message using inputs from DKIM and several other systems of its choosing (e.g. SPF) without consulting any reputation system at all.  Reputation is just another input to the assessor.  The total set and weighting of the assessor's inputs is both a matter of software design and local policy.
> 
> They are certainly disjoint in my implementation.

There are a few points that seem to be lost in all of this:

1) People saying that d= is THE IDENTIFIER are overloading the value: d= a routing
    label to a particular DNS subtree. Whether it has anything to do with THE
    IDENTIFIER is purely coincidental. The assumption that these two functions are
    identical is bogus. i= was supposed to be this stable value detached from the
    mechanical DNS routing function.

2) assessors are going to use what they find useful regardless of whether we hurry
    this draft out any faster or with any less review.

3) What's "useful" to assessors, d=, i=, or even x= is out of scope for the DKIM wg.
    The level of interoperability being pursued here much higher level than
    anything we ever signed up for. We shouldn't force normative changes on implementations
    for functions outside of the scope of this working group.

4) #3 is doubly true since we don't even have any feedback, or an actual problem being
    reported in the field. when I asked about this at the SF meeting, I got a lot of
    bluster about "not revisiting first principles".

In conclusion, changing a spec absent actual problems in the field and to solve problems
that are outside of charter seems dubious and dangerous. Doing so as an emergency must-fix
update is even moreso: it tells the world that there's something dreadfully wrong with
DKIM when that's far from the case.

		Mike