At Tue, 10 Aug 2004 10:40:19 -0700, Ted Hardie <hardie(_at_)qualcomm(_dot_)com>
wrote:
At 7:14 PM -0400 8/9/04, Meng Weng Wong wrote:
While such a change is, from the standpoint of architectural
purity, absolutely the correct thing to do, I fear that in
practice it may lead to confusion, needless duplication of
records, and a failure to achieve the intended objective.
In other words, it is my opinion that engineering
considerations do not weigh in favour of changing the string.
I particularly do not want to see a world where the norm is:
example.com TXT "v=spf1 a mx ptr"
example.com TXT "v=spf2 a mx ptr"
Both records would contain the same content, yet senders
might feel the need to publish both "just to be on the safe side".
Both records do _not_ contain the same information. The first
record has a target of MAIL_FROM; the second has a target
of PRA. The fact that the strings "a mx ptr" happen to be
the same in both records does not change that fundamental
fact. [...]
Surely this is a distinction without a difference. If you ask me,
"What checks do you want me to make on email which arrives with
MAIL FROM: george(_at_)m5p(_dot_)com?", and then you ask me "What checks do
you want me to make on email which arrives with a PRA of
george(_at_)m5p(_dot_)com?", would you be surprised if I answered
"... a mx -all" in both cases? Perhaps there are cases in which
people want the checks to be different, but this will be the
exception (and I think a rare one) rather than the rule. I
strongly agree with Meng that the problems associated with
changing the version string outweigh the possible theoretical
advantage.
-- George Mitchell