What is “Received-SPF”?

Received-SPF is an older header format for recording SPF authentication results. It predates the consolidated Authentication-Results header but is still widely used.

Example:

Received-SPF: pass (google.com: domain of newsletter@mail.example.com designates 192.0.2.1 as permitted sender) client-ip=192.0.2.1; envelope-from="newsletter@mail.example.com"; helo=mta.example.com

Components:

• pass/fail/softfail/neutral/none: The SPF result
• Explanatory text: Human-readable description of the result
• client-ip: The IP address that was checked against SPF
• envelope-from: The Return-Path domain used for the check
• helo: The hostname provided in the SMTP HELO/EHLO command

When both Received-SPF and Authentication-Results exist (common), they should show the same SPF result. If they differ, investigate: it might indicate multiple checks at different servers.

Received-SPF provides more detail than the SPF portion of Authentication-Results, making it useful for debugging. The explanatory text often clarifies why the check passed or failed.