Header From vs Envelope From
The single most-confused topic in email auth. This page explains both headers, where SPF checks, where DMARC checks, and why a SPF-passing email can still fail DMARC.
| Scenario | Header From | Return-Path | SPF | DMARC |
|---|---|---|---|---|
| Direct send from your own MTA | you@yourdomain.com | you@yourdomain.com | Pass (your SPF lists your MTA IP) | Pass (aligned) |
| Send via ESP (no custom Return-Path) | you@yourdomain.com | bounce@esp.example.com | Pass (ESP's SPF lists its MTA) | Fail (Header From and Envelope From not aligned) |
| Send via ESP (custom Return-Path) | you@yourdomain.com | bounce@yourdomain.com | Pass (you CNAME to ESP's SPF) | Pass (aligned via custom Return-Path) |
| Forwarded through mailing list | original@sender.com | list@list-host.com | Fail (list-host MTA not in original sender's SPF) | Fail unless ARC seal present |
| Phishing — spoofed From | ceo@yourcompany.com | attacker@evil.com | Pass (evil.com's SPF allows the attacker's MTA) | Fail (not aligned, p=reject blocks it) |
SPF checks the Envelope From (Return-Path). DMARC requires the Envelope From domain to align with the Header From domain. Most ESP-related DMARC failures are alignment problems, not SPF problems.
Reference page with worked examples: a forwarded email, a marketing platform send, a bounce, and a phishing attempt — each annotated to show what's in From vs Return-Path and which checks pass.
Anytime SPF is passing but DMARC isn't (or vice versa). The answer is almost always a Header From / Envelope From alignment mismatch.
FAQ
Why does SPF pass but DMARC fail?+
SPF checks the Envelope From (Return-Path). DMARC requires the Envelope From domain to align with the Header From domain. ESPs that send with their own Return-Path break that alignment unless you set up custom Return-Path.
Keep going
Articles, glossary entries, and other tools on the same topic.
You know the rule. See where you sit against it.
Reference pages tell you the benchmark. Outsolvi tells you whether your team is above or below it — per-rep, per-deal, per-week — and which behavior changes move the number. From $7/user/mo yearly.
See your numberNate built Outsolvi after watching every email-tracking tool he had ever used lie to him about opens. Outsolvi runs Tier 1 to 5 confidence scoring on every open, native in Outlook and Gmail, so the number on the dashboard is one a rep can actually act on.
We update these pages when the underlying mechanics change — new mailbox-provider rules, new tracker behavior, new measurement gaps. The dates above are real revisions, not auto-touches.