On Thursday 20 July 2006 16:50, Robert Millan wrote:
On Thu, Jul 20, 2006 at 04:33:53PM -0400, Scott Kitterman wrote:
Do you generate X-Best-Guess for all messages or just those that don't
have an SPF record?
Although my mail should pass SPF, it would have never passed best guess
(I realize that you get this message with a listbox Mail From, so it's
irrelevant to the list messages, but in general I think there are a lot
of legit senders that don't pass best guess.
AFAIK, best-guess is defined as "same as spf, except when no record is
found, assume a/24 mx/24 ptr ?all". I generate this header for all
messages. When they have an SPF record, the result is the same as
Received-SPF of course.
OK. I would have thought it different. What I meant by best guess on all
messages is checking to see if messages that Pass a real SPF check would also
pass the a/24 mx/24 ptr test.
Btw, I don't implement this policy myself. My MTA just relies on:
spfquery --ip 1.2.3.4 --mail-from foo(_at_)bar(_dot_)org --helo helo # for
SPF
spfquery --ip 1.2.3.4 --mail-from foo(_at_)bar(_dot_)org --helo helo
--guess true #
for best-guess
OK.
There is a reason that best guess isn't in RFC 4408 and this discussion is
probably one example of why.
Scott K
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