Whether it exists
No record, or more than one, means receivers ignore DMARC and anyone can send as your domain.
Free tool
DMARC checker
Find out whether your domain is protected from spoofing, or just being monitored — and what to change next.
Nothing is stored. Works with any domain, not just ours.
What it checks
What we look at in your DMARC record
DMARC lives at _dmarc.yourdomain as a TXT record. We read it and tell you what it means in practice.
The policy
none only monitors. quarantine sends failing mail to junk. reject refuses it. We tell you which you have and what it does.
Reporting
Without a rua= address you never see who is sending as you, and cannot safely tighten the policy.
Partial enforcement
A pct= value below 100 applies your policy to only part of the failing mail. Useful while tightening, not as a destination.
What a DMARC policy actually does
DMARC (Domain-based Message Authentication, Reporting and Conformance) closes the gap SPF and DKIM leave open. It requires a message to pass SPF or DKIM for the domain in the visible From address, and tells receivers what to do with mail that does not:
- p=none — deliver it anyway, but send me reports. Monitoring only; it does not stop spoofing.
- p=quarantine — treat it as suspicious, which usually means the junk folder.
- p=reject — refuse it. The strongest protection, and where every business domain should end up.
Moving from none to reject safely
Going straight to reject risks losing genuine mail from a service you forgot was sending as you — the invoicing system, the website form, the CRM. The safe route is:
- Publish
p=nonewith a reporting address. Our DMARC record generator builds the record. - Read the reports for a few weeks. Every service sending as you will appear, with whether it passes.
- Fix the ones that fail — usually by adding them to SPF or setting up DKIM with that provider.
- Move to
p=quarantine, thenp=rejectonce the reports stay clean.
Why it matters for UK businesses
Since 2024, Google and Yahoo have required DMARC from anyone sending large volumes to their users, and Microsoft followed for Outlook.com in 2025. More importantly, a domain without an enforced DMARC policy is easy to impersonate — the starting point for most invoice and payment-diversion fraud. The UK’s National Cyber Security Centre recommends DMARC for exactly this reason.
When we checked 256 UK small businesses in October 2026, three in four had no enforced DMARC policy — see our research on email impersonation.
This checker reads the policy, reporting and enforcement percentage. It does not yet check the subdomain policy
(sp=), alignment settings, or whether an external reporting domain has authorised your reports. Our
guide to SPF, DKIM and DMARC covers those.
Questions
About DMARC
Where is the DMARC record published?
As a TXT record on the host _dmarc — for yourcompany.co.uk, the full name is _dmarc.yourcompany.co.uk. A domain should have exactly one.
Which DMARC policy should I use?
Start with p=none and a reporting address. When the reports show every genuine sender passing, move to p=quarantine, then p=reject. Reject is the goal; none on its own does not stop spoofing.
What are rua and ruf?
rua is where aggregate reports go — daily summaries of who sent mail as your domain and whether it passed. ruf is for individual failure reports, which few providers send because they can contain message content.
Does DMARC cover my subdomains?
Yes. Unless you set a separate subdomain policy with sp=, subdomains such as mail.yourcompany.co.uk inherit the main policy.
Do I need DMARC if we only send normal business email?
Yes. The bulk-sender rules are one reason, but the main one is protection: without an enforced policy, anyone can send email that appears to come from your domain to your clients and suppliers.
Related tools and guides
Rather have it done for you?
SPF, DKIM and DMARC are set up and monitored for every MyExchangeServer customer. Or send us your results for a second opinion from an engineer.
- Free assisted migration
- No set-up fee, no minimum term
- UK data centres, UK engineers