Glossary
Return-Path — The Envelope Sender
Return-Path is the envelope sender used for bounces — separate from the visible From: header. SPF checks the Return-Path domain (or HELO/EHLO context). DMARC alignment compares Return-Path domain to the From: domain for SPF alignment.
Why ESPs use their own domain
Many ESPs set Return-Path to bounce domains they control — so DKIM alignment to your brand domain becomes critical for DMARC.
FAQ
Is Return-Path the same as From?
No — From is what users see; Return-Path is the SMTP bounce address.
Why does SPF use Return-Path?
SPF checks the envelope — not the header From:.
How do I align DMARC with ESP mail?
SPF aligned Return-Path or DKIM d= aligned to From — see DMARC alignment.