[ietf-dkim] forward movement, please? (was RE: Are lookalike domains like parent domains?)

[Jim Fenton]

Dave Crocker wrote:
> Arvel Hathcock wrote:
>   
>> I propose that the side advocating removal of the NXDOMAIN check agree 
>> to language which makes this step AT LEAST a SHOULD and preferably a MUST.
>>     
>
>
> Having the ADSP specification include normative text that calls for validating 
> the From field domain name does two things:
>
> 1. Couples an entirely separate and more generally useful mechanism (checking 
> domain name validity) to one that is considerably more limited (ADSP).
>
> 2. Modifies SMTP.  (Yes, really.)
>   

This is a reason that we shouldn't reference a domain existence check in 
a separate document (if one indeed exists).  A separate description is 
likely to be interpreted in a way that modifies SMTP, while the 
description in ADSP simply returns the ADSP result, "the domain does not 
exist."  The specification is carefully non-normative what to do in this 
case, and therefore does not modify SMTP.
> Having non-normative text that describes it serves to promote the idea but not 
> couple it with the fate of ADSP.
>   

Having the ADSP result depend on non-normative language in this case 
does not meet the bar of interoperability that we need to achieve.  
Making it non-normative means that two spec-compliant implementations of 
ADSP would return completely different results for non-existent domains.

-Jim