[ietf-dkim] ISSUE 1573: Modify ADSP Lookup Procedure

[John Levine]

>>              <t hangText="Note:  "> The results from DNS queries that are
>>                intended to validate a domain name unavoidably approximate
>>                the set of Author Domains that can appear in legitimate email.


>I'd like to suggest that we use a different word than "approximate" in 
>the above discussion and in the Levine draft.

I wasn't thrilled by "approximate", but I couldn't think of a word
that more accurately captured what I was trying to say.

> "Approximate" may give the impression that the error may be in
> either direction, ...

Depending on local configurations, there might be.  My MTA is set up
so that it recognizes domains for local hackery that aren't visible in
the DNS.  I realize this is out of the scope of 2821, but my thought
was that there's nothing short of trying to deliver the mail and
seeing what bounces to accurately tell what's valid.

I suppose that "overapproximate" would be OK within the constraints of
2821.

R's,
John