Definition
Envelope-From
The Envelope-From is the address announced by the SMTP MAIL FROM command at the start of the conversation between servers; it is where bounces are routed, it is what SPF checks, and the recipient never sees it in their mail client.
It is to the displayed address what the envelope is to the letter: the postman reads the envelope, the reader reads the letterhead. Nothing requires the two to match. That freedom is what makes impersonation possible, and DMARC alignment is what closes it.
When an email service provider sends on your behalf, the Envelope-From very often carries their domain (bounces.provider.com) rather than yours. SPF then passes, but on the wrong domain, so alignment fails. This is the single most common reason DMARC fails on perfectly legitimate mail.
- Also known as
- MAIL FROM, Return-Path, bounce address, RFC5321.From, envelope sender
- Standard
- RFC 5321, §4.1.1.2