What is Return-Path?

The Return-Path is the address where bounces and other email feedback are sent. It is specified by the Return-Path header in an email. For example, the default Return-Path for emails sent through Postmark is:

Return-Path: <pm_bounces@pm.mtasv.net>

It is also described as:

• bounce address
• reverse path
• envelope from
• MAIL FROM

Why set a custom Return-Path?

DMARC requires the domains in the Return-Path and From headers to match in order for the SPF check to pass. Many email providers will set the Return-Path for you, so it’s common for the Return-Path and From domains not to match and therefore DMARC will not be aligned.