RFC 5322 laid down email security specifications for Sender Policy Framework
RFC 5322 defines the syntax for Internet email headers. SPF, DKIM, and DMARC rely on these headers to authenticate emails and prevent phishing. Published in October 2008 as an update to RFC 2822, RFC 5322 is widely used for formatting email headers and bodies. RFC 5322 doesn’t say anything about how SPF should be set…