Even with your discardable adsp setting, it becomes a
matter of the order of checks at the receiver's gate (eg, whitelist
first, then adsp...)
But since mailbox providers already manage reputation at scale, how much
of a burden is adding this bit to the mix? Remember this only affects
mailbox providers who have decided to do DKIM blocking based on ADSP
discardable policies (for some, if not all senders).
You appear to be asking recipients to distinguish among legit directly
sent paypal transaction mail, legit paypal mail that comes through
known-to-be-real mailing lists, and any other paypal mail that is
presumably illegitimate. This is a huge burden, since you're asking
every mail system in the world to distinguish between legit list mail
and legit other mail, something they don't have to do if they just
deliver mail which has a good reputation.
Since you're describing two mailstreams, directly sent paypal transaction
mail and list relayed individual mail, why wouldn't it be a better idea and
less work (for everyone other than paypal at least), to separate those two
streams so the recipients don't have to guess which messages belong to
which ones?
Free bonus: if you move the individual mail out of the transaction
stream, if you are able to recognize list mail, you instantly know
that any paypal.com mail arriving from a list has a problem.
R's,
John
_______________________________________________
NOTE WELL: This list operates according to
http://mipassoc.org/dkim/ietf-list-rules.html