On Tue, Mar 22, 2005 at 07:07:17AM +0000,
Graham Murray <graham(_at_)gmurray(_dot_)org(_dot_)uk> wrote
a message of 14 lines which said:
and that the mx only causes an 'A' DNS lookup not an 'AAAA'
This is clearly wrong. Although the lack of a proper standard for SPF
will make it difficult to convince your colleague. In the mean time,
draft-schlitt-spf-classic-00.txt says (section 5.4):
5.4 "mx"
...
check_host() first performs an MX lookup on the <target-name>. Then
it performs an address lookup on each MX name returned.
"address lookup", not "A lookup" or "IPv4 address lookup".
I remember MARID patches to make more crystal-clear that "address"
means "IPv4 or IPv6 address" but I believe that the current draft is enough.