I've got a few users on my server that forward their email to gmail, and sometimes my server accepts email that gmail rejects bounces back to me. When that happens I try to see if there is something I could have done better on my server so that I wouldn't have accepted that email in the first place. Today I had a bounce with the following message:
Remote host said: 550-5.7.1 Unauthenticated email from aol.com is not accepted due to domain's 550-5.7.1 DMARC policy. Please contact the administrator of aol.com domain if 550-5.7.1 this was a legitimate mail. Please visit 550-5.7.1 https://support.google.com/mail/answer/2451690 to learn about the 550 5.7.1 DMARC initiative. i6si10846092pgt.798 - gsmtp Looking at the message and the headers, it was clearly spam with a forged sender. It's exactly the kind of email I don't want to accept, let alone forward to another service. How can I add DMARC policy checking to my filter path, to prevent my server from accepting this junk in the first place? -Chris
