I am trying to identify, why some of my e-mails are being marked as spam by recipients, and have therefore set up SPF and DKIM. In order to check that they can be verified, I set up aggregated DMARC reports.

When looking at one report, I can see the following:


Is there any way to tell, where the domain from the auth_results>spf>domain field comes from? It is unknown to me and not related to any Microsoft Outlook related domains (which is hosting my E-Mails).

Any help identifying the source for the unknown domain would be appreciated.


1 Answer 1


SPF checks are performed using the RFC 5321.MailFrom, HELO/EHLO ("HELO") domain, or both. You would have to see the headers of the message to determine where the unknown domain was used, but it appears to be a domain without an SPF record.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .