[ietf-dkim] Are subdomains like parent domains?

[Jim Fenton]

Al Iverson wrote:
>
> So, a potential way to address this without any sort of "tree walking"
> functionality would be:
> - As a sender, publish ADSP records for all domains/zones/fqdns you know about
> - Recommend that receivers reject mail from non-existing FQDNs used in
> PRA or MFROM (or somesuch).
>
> This seems workable. Others who prefer treewalking functionality, why
> does this not work for you? Where does this specifically fall down?
>   

Considering that "domains you know about" includes everything with an A 
record, the "publish ADSP records for all" part may not be practical for 
domains with tens of thousands of hosts without new DNS tools.

There's also the question of what constitutes a non-existing FQDN 
(NXDOMAIN?  MX/A/AAAA all fail?) and whether that check should be 
included in ADSP but that's covered in another thread.

-Jim