Glossary
Email authentication
Authentication-Results
A header the receiving system adds recording the authentication checks it performed and their outcomes. Trustworthy only within the system that wrote it — anyone can add the header upstream.
Defined in RFC 8601.
Where this appears
The lessons that use this term, and what each is for.
Email Authentication FundamentalsReading the Authentication-Results headerRead an Authentication-Results header and say what the receiver checked, what it concluded, and whose word you are taking.SPF PractitionerA method, not a checklistTake an SPF complaint and reduce it to one named failure with evidence.SPF PractitionerResults that look impossibleExplain a pass that was rejected, and a fail from a host you know is authorised.DKIM PractitionerEvery dkim= valueMap each result in Authentication-Results to the stage of verification that produced it.DMARC PractitionerFour causes, one methodTake a failing message to one of four causes using only its headers.DMARC PractitionerARC, in practiceSay what an ARC chain changes for your mail, and what it does not entitle you to.