Return-Path

Return-Path is a header that the delivering SMTP server inserts at final delivery. It preserves the reverse path from the SMTP envelope for error reports. This technical delivery does not prove that a person read the message.

Examine a delivered test message

In the fictional check design, the team receives message R-663 in an approved test mailbox. The Return-Path field contains the sending service’s technical return address; the visible From field contains the portal address. This difference alone does not establish a fault.

The team maps the value to the intended sending route and establishes where bounces are actually processed. This investigation does not require real customer email. The described workflow is a check design, not a delivery result achieved here.

Distinguish the transport envelope from the header

Envelope-From is used during SMTP transmission; Return-Path records the return information in the delivered message. An application should not simply insert the header in advance as delivery evidence. A plausible return address also confirms neither the displayed person nor valid authentication. Each requires the appropriate checks.

Sources

• IETF: Simple Mail Transfer Protocol