[Michel Bouissou]
Funny enough, when I post to this list, when my message gets
forwarded by
listbox server, I quite quickly receive a number of SPF DNS
queries which do
NOT originate from listbox's server (that would be logical), but OTOH
originate from other machines, surely MTAs at recipient's domains.
Have you done any reverse DNS or WHOIS on the IP addresses in doing the
DNS requests? Surely they will lead to an MTA, which will most likely
give you the domain names of the people with broken implementations.
Then you could cross-reference with the list archive for that domain,
right?
Of course, listbox doesn't appear to have archives of this list online.
I have about a six-month archive of the list that I can search for
domain names you if you'd like.
If the person has never posted... well, that would be more trouble than
it is worth to track them down.