On 5/29/2021 7:23 AM, John R Levine wrote:
On Sat, 29 May 2021, Alessandro Vesely wrote:
ARC is a completely different thing. It introduces a third party, the
sender, which modifies the message header in such a way to induce
receivers to accept a message even if it fails DMARC. Semantically,
it is very similar to Dave's Use of the Sender Header Field.
Ho, it is really nothing like that. It provides log info to so that the
final recipient can retroactively do filtering that the intermediate
hosts didn't. It is true that you do have to know which intermediate
hosts might plausibly do that, but small systems rarely get ARC'ed mail
from more than a handful of places.
I see no conflict between these two methods.
Me either.
One says "Here is the original author information."
The other says "1) When I got this message, here is how the DMARC
evaluation came out, and you can trust these results if you trust me;
and 2) Here is the collaborative handling sequence since that evaluation"
Very different semantics.
d/
--
Dave Crocker
Brandenburg InternetWorking
bbiw.net
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