3. Terminology and Definitions

Key terms include Authenticated Identifier, Author Domain, DKIM Signing Domain, SPF Domain, DMARC Policy Domain, DMARC Policy Record, Domain Owner, Domain Owner Assessment Policy, Enforcement, Identifier Alignment, relaxed alignment, strict alignment, Mail Receiver, Monitoring Mode, Non-Existent Domains, Organizational Domain, Public Suffix Domain (PSD), Public Suffix Operator (PSO), PSO-Controlled Domain Names, and Report Consumer.

RFC5322.From, RFC5321.MailFrom, DKIM d= domains, SPF results, Organizational Domains, and policy domains must be kept distinct when evaluating DMARC.