In article <1d458e76-ab61-db28-79cb-6aabcab4ff3b@mtcc.com> you write:
I've been saying for years that it should be possible to create the concept of DKIM-friendly mailing lists. ...
I suppose, if your users are OK with no subject tags, message footers, or any of the other cruft that list users have taken for granted for the past 30 years. The people who brought us DMARC have a new anti-DMARC thing called ARC that is intended to help recipients guess whether a message with a broken signature came through a mailing list. It's a kludge, but since it's a kludge that Gmail has already implemented, you'll be seeing more of it. Returning to the original question, if a message has no DKIM signature, that doesn't say anything particularly bad, but it does mean that the sending IP is your main bit of info to decide whether it's mail you want, which has issues of its own. R's, John PS: details here https://dmarc.org/resources/specification/ PPS: Please spare us pontification about why ARC can't possibly work unless you're prepared to cite section numbers in the ARC spec supporting your argument.