On Aug 20, 2004, at 12:11 AM, wayne wrote:
The creation of a minor version number was mandated during the IETF-60
session. No semantics of what the minor version number should do were
given. I've talked with both Mark and Meng about this, and we all
agree that we can't think of any use for a minor version, which was
why it wasn't there in the first place.
As SPF 2.0 is a policy that speaks only to how to deal with the PRA, I
could see a minor version being useful if additional policy classes are
added.
For example, today:
example.com. IN SPF2 "spf2.0/pra mx a:smtp.example.com ?all"
Tomorrow:
example.com. IN SPF2 "spf2.1/pra mx a:smtp.example.com
?all"
IN SPF2 "spf2.1/csa mx a:smtp.example.com a:listserv.example.com
-all"
4.3.2.1.IN-ADDR.ARPA IN SPF2 "spf2.1/mta a:smtp.example.com"
Where pra is the policy a receiver should apply when performing
authorization based on the PRA, csa on the EHLO domain, and mta on the
client IP.
Perhaps a major version change would be in order if, say, SPF were to
adopt an XML or binary record structure in the DNS. Perhaps also if
the existing language's mechanisms are modified.