The following shouldn't be discouraged:
From: foo(_at_)bar(_dot_)com
DKIM-Signature: ... d=43343.rep.bar.com ...
where 43343.rep.bar.com doesn't have any MX or A record.
On further reflection, you're right. The signature isn't an email address
or a web site, so there's no reason it needs anything more than a key
records.
Regards,
John Levine, johnl(_at_)iecc(_dot_)com, Primary Perpetrator of "The Internet
for Dummies",
Information Superhighwayman wanna-be, http://www.johnlevine.com, ex-Mayor
"More Wiener schnitzel, please", said Tom, revealingly.
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