Glossary
Mail transport
Header From
The From: header inside the message. This is the identity a mail client displays, and it is the identity DMARC is built to protect. SPF does not check it.
Defined in RFC 5322 §3.6.2.
Where this appears
The lessons that use this term, and what each is for.
Email Authentication FundamentalsThe two From addressesTell the envelope sender from the header From in a raw message, and say which one the recipient sees.Email Authentication FundamentalsThe gap SPF and DKIM leave openDemonstrate a message that passes both SPF and DKIM and still deceives the recipient.DKIM PractitionerChoosing what to signPick an h= list that resists tampering without making the signature needlessly brittle.