Email authentication, or validation, is a collection of techniques aimed at providing verifiable information about the origin of email messages by validating the domain ownership of any message transfer agents (MTA) who participated in transferring and possibly modifying a message.
en.wikipedia.org/wiki/Email_authentication#contentSub
Authentication methods
- DKIM: DomainKeys Identified Mail
- DMARC: Domain-based Message Authentication, Reporting and Conformance
- FCrDNS: Forward-confirmed reverse DNS
- SPF: Sender Policy Framework