Paste raw email headers to trace delivery path, check SPF/DKIM/DMARC authentication, and diagnose routing issues.
In Gmail: click the three-dot menu → "Show original". In Outlook: open the email → File → Properties. In Apple Mail: View → Message → All Headers.
Headers reveal the sender's server, delivery path (hops), authentication results (SPF, DKIM, DMARC), the sending application, timestamps, and signs of spoofing or relay issues.
SPF verifies the sender's IP is authorized, DKIM adds a cryptographic signature, and DMARC ties SPF and DKIM together with a policy for handling failures.