We are seeing an issue with one of our client environments (Exchange 2010) where they want to forward mail to a personal mailbox such as gmail.com – When the mail hits exchange and it forwards to gmail it will get an NDR about a DMARC issue. We see it with environments that have Dmarc settings set to reject such as facebook, yahoo etc.
It would seem in the forwarding process exchange changes the header and dmarc fails. I’m interested if anyone has been able to address this of if there is a fix for this. So right now it’s is unreliable some work, some don;t but Murphy’s law dictates that the important mail will be on one that does not work.
— 5.7.1 Unauthenticated email from example.com is not accepted due to
domain’s DMARC policy. Please contact the administrator of
example.com domain if this was a legitimate mail. Please visit https://support.google.com/mail/answer/2451690 to learn about the
DMARC initiative. r185si7696144wma.136 – gsmtp