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DMARC result: PASS. Disposition: none. DKIM aligned: true. SPF aligned: false. Passing via: dkim. Steps: Header-From domain: example.com DKIM pass (d=example.com), relaxed: org "example.com" = "example.com" → aligned ✓ SPF pass (envelope-from mail.google.com), relaxed: org "google.com" ≠ "example.com" → not aligned DMARC: PASS (via DKIM) → disposition: none
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DMARC Policy Simulator

Input a policy configuration and message scenario. See exactly what a receiving mail server would do, and why.

Scenarios:

Result

PASSvia DKIM

At least one mechanism passed and aligned with the From: domain.

ALIGNEDDKIM (adkim=relaxed)
NOT ALIGNEDSPF (aspf=relaxed)

Disposition

none (message passes)

Evaluation steps

  1. 01.Header-From domain: example.com
  2. 02.DKIM pass (d=example.com), relaxed: org "example.com" = "example.com" → aligned ✓
  3. 03.SPF pass (envelope-from mail.google.com), relaxed: org "google.com" ≠ "example.com" → not aligned
  4. 04.DMARC: PASS (via DKIM) → disposition: none
Parameters

DMARC Policy

Message Scenario

See your real alignment rate across all senders.

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No credit card required. Free tier monitors 1 domain.

Runs in your browser, no account required. Track your real sending sources over time.

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Why simulate before changing your policy

Moving from p=none to p=quarantine is the step most developers hesitate on. If a legitimate sender isn't covered by your SPF or DKIM setup, their mail goes to spam the moment you flip the policy. This simulator lets you preview exactly what a receiving mail server would do for any sender scenario given your current DMARC policy, DKIM alignment result, and SPF alignment result, before you commit to anything.

Key reasons to simulate first

  • Find uncovered senders:see which sender scenarios would fail under a stricter policy before you enforce it
  • Understand alignment logic:DMARC passes when either DKIM or SPF aligns; the simulator shows you which path each scenario takes
  • Test subdomain policy:the sp= tag controls subdomains separately; confirm your subdomain behavior before tightening
  • Validate your changes:after updating your DMARC record, confirm the new policy evaluates exactly as intended

Frequently asked questions

What is a DMARC simulator?
A DMARC simulator takes a policy and a set of message properties (DKIM alignment result, SPF alignment result, sending domain) and shows you what disposition a receiving server would apply: none, quarantine, or reject. It's useful for understanding the alignment logic before making policy changes that affect real mail delivery.
Why should I simulate before changing my DMARC policy?
Because a policy change is applied to all mail immediately. If you have a sender that's failing alignment (a marketing tool, a CRM, a transactional ESP that wasn't configured correctly), moving to p=quarantine means that sender's mail goes to spam. Simulating first lets you identify those gaps and fix them before the policy has any effect. See the p=reject vs p=quarantine guide for the full decision framework.
What does DMARC quarantine do?
p=quarantine tells receiving servers to route mail that fails DMARC authentication to the spam or junk folder rather than the inbox. It's the middle ground between p=none (deliver everything, just report) and p=reject(bounce failing mail entirely). Most domains move to quarantine first to catch any legitimate senders that weren't covered before committing to full rejection.

Want continuous monitoring instead of one-off checks?

DMARCdrift ingests your DMARC reports automatically, tracks alignment across every sender, and tells you when you're actually ready to move from p=none to enforcement, with no manual report parsing required.

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Run policy simulations on real incoming reports. Start free.

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