On Sat, 21 May 2022, Viktor Dukhovni wrote:
You don't have to accept such mail [...]
Don't forward mail that for which the input MTA is expected to be the
final destination.
Maybe I'm misunderstanding, but my interpretation is that the question is
"why are you accepting that mail?" and saying "don't forward mail" is kind
of like "here is a footgun; don't pull the trigger".
My understanding is that the mail which is looping was accepted for
forwarding although no recipient exists, hence it's the bounce which is
looping.
HTH, apologies if I've got it wrong...
--
Fred
