The policy results described above correspond to the draft DKIM
sender signing practises policy procedures. Detailed descriptions, with
the algorithm steps indicated in square brackets, are included here.
- DKIM_PRESULT_NONE is returned if no policy check has been done
yet for the message.
- DKIM_PRESULT_NXDOMAIN is returned if the policy check was done
and it was discovered that the author's domain does not exist.
- DKIM_PRESULT_FOUND is returned if the policy check has been
done and a policy at the author's domain was found and returned.