wayne wrote:
there are even DNSBLs that, IMHO, do such stupid things as
list people who have a CNAME to their MX host and people
who, IMHO, do such stupid things as use those DNSBLs to make
hard rejects of email.
Accepting mail from a bogus MX is a bad plan, depending on the
MTA sending to an MX with an IP instead of a name might fail.
While that CNAME thing might be only as bad as a:11.22.33.44
in SPF I don't see a reason where it's useful. If example.com
has an MX mail.example.com with a CNAME io.example.com with a
_second_ CNAME example.com then this _is_ bogus (= PermError).
Bye, Frank (RFCI supporter for 3 years)