I have seen on Listserv mail too.  It has also shown up on posts to the Office 365 list (Mailman list, hosted at UCDavis).  Had a rather hostile session with someone from MS yesterday (in fairness, I was not exactly in a good mood) and went after them on RFC822 Sec 4.4.1 and 4.4.2 (yes, there are more current, but I don't believe these sections have been superseded - yet)
It kind of culminated with me asking if his recommendation was the UGA SPF designate UCDavis.  As I say, it was not altogether friendly, and I wasn't in such a good mood (though I do feel bad venting on the tech support folks).  At the conclusion, I believe he actually did read the sections.  Even so, this is coming from Exchange Online Protection (EOP).  It seems *like* (but not quite) the beloved DMARC issue of 2014, and I doubt there is any good resolution.
--joe

________________________________________
From: LISTSERV Site Administrators' Forum <[log in to unmask]> on behalf of Helmke,Richard A <[log in to unmask]>
Sent: Monday, November 21, 2016 9:18 PM
To: [log in to unmask]
Subject: Office 365 and fraud detection errors

We are running a RedHat/Postfix configuration of LISTSERV 16.0-2014B.  Within the last 20 days a number of our subscribers on various lists have started receiving:

“This sender failed our fraud detection checks and may not be who they appear to be. Learn about spoofing at http://aka.ms/LearnAboutSpoofing”

This occurs after the subscriber on Office 365 has submitted a posting and after distribution his copy is sent to him with this flag -- no other subscribers on other domains see this error, but other subscribers in his domain also see this warning.


We have a valid SPF record in place for listserv.cuis.edu, but have not implemented any kind of DKIM or DMARC records on LISTSERV (or elsewhere).

Is this a 'new' common problem?  Is there a workaround (there are many domains affected because many of our subscribers are Office 365 users)?  Both LSoft and Microsoft have suggested that a valid SPF record for our LISTSERV should be enough, but that is obviously not working for us.

-Rich Helmke

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