Guy wrote:
ISPs should limit the number of lookups to 9 or 8 so that a
customer could use "include:ISP.com". Is this noted as a
SHOULD in the spec?
No, it's kind of obvious, and you could bypass restrictions
by copying parts of the sender policy instead of an "include".
Not good enough for some per-user policy tricks, and to copy
policies of 3rd parties is a PITA, so I hope that ISPs try
to limit their use of DNS-mechanisms and redirect=. And I do
hope that the next generation of SPF wizards and validators
can count to ten.
Bye, Frank