On May 24, 2010, at 5:27 AM, Ian Eiloart wrote:
We have one concrete failure scenario, in which someone who publishes
dkim=discardable sends mail to a MLM that as usual breaks the signature,
a subscriber's mail system carefully follows the ADSP and rejects that
mail, causing the subscriber to be bounced off the list. (This really
happened, on an IETF list.) The advice is obvious a) put a shim in
front of your MLM to reject discardable mail and b) the usual advice not
to use ADSP at all, but it definitely needs publishing.
The other piece of advice should be to actually discard, rather than
rejecting, discardable email. That would have protected the subscriber from
The advice should be to discard the mail vs. bouncing it back to the MLM. That
solves the use case of subscribers being auto-unsubscribed to mail lists
without undermining all the other use cases that led the IETF to standardize
ADSP in the first place.
NOTE WELL: This list operates according to