DMARC Record Builder

Build a DMARC record step by step: policy, subdomains, percentage, report addresses and alignment, with advice for moving from none to reject.

DMARC tells receivers what to do with mail that claims to be from your domain but fails SPF and DKIM, and where to send reports about it. Start with p=none and a report address, read the reports for a few weeks (the DMARC Report Analyzer opens them), then tighten to quarantine and reject. Report addresses you type stay in your browser. Runs in your browser.

Domain

Policy for mail that fails

none: monitor only (start here)

quarantine: deliver to spam

reject: refuse it

Subdomains

Apply to % of failing mail

Send aggregate reports (rua) to

Daily summaries. Separate several with commas.

Send failure reports (ruf) to (optional)

Alignment

Strict DKIM (adkim=s)

Strict SPF (aspf=s)

p=none only monitors: failing mail is still delivered. Start here, read the reports for a few weeks, then move to quarantine and reject.

No aggregate report address (rua): you won't see who sends as your domain, which is what tells you it's safe to tighten the policy.

Record to add

Name	Type	Value
_dmarc.example.com	TXT	v=DMARC1; p=none

Zone file (BIND) format

_dmarc.example.com.	3600	IN	TXT	"v=DMARC1; p=none"

Once it's published, check it with DMARC Lookup or the whole setup with Email Health. Need SPF first? SPF Record Builder.