On May 24, 2010, at 6:38 PM, John Levine wrote:
Refusing signups from those domains is probably a bit extreme, though.
What about a warning at signup time if a "discardable" ADSP record is
found for the registrant's domain?
That doesn't help. In the IETF's scenario, domain A sent mail which
was marked discardable to the list, and recipients at domain B were
rejecting it and the people at B got bounced off the list. I'd have
to squint awfully hard to come up with an argument that it is wrong to
reject unsigned discardable mail at SMTP time.
I think that Murray was suggesting that in addition to rejecting all
mail from domain A it would be polite to also warn anyone from
domain A who subscribes to the list that their mail would be
rejected (which seems good UX design to me).
Since ADSP causes problems for innocent bystanders, I think it's
reasonable to decline A's mail in the first place. This is doubly
true since the ADSP RFC rather specifically says that you shouldn't
mark a domain discardable if its users send mail to lists.
It causes no problems at all to innocent bystanders in that case - the
recipient at domain B is a willing participant who has chosen both
to pay attention to ADSP and to respond to it by rejecting, rather than
discarding, mails labeled "discardable".
Cheers,
Steve
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