What is DMARC and how to check it
DMARC is the policy that ties SPF and DKIM together — it tells receiving servers what to do with mail that fails the checks, and reports who is sending as you.
Tool: DMARC checker
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What it is
DMARC (Domain-based Message Authentication) is a DNS TXT record at_dmarc.example.com, e.g. v=DMARC1; p=none; rua=mailto:reports@example.com.It sets a policy — none, quarantine or reject — and an address to receive aggregate reports.
Why it matters
SPF and DKIM verify mail, but only DMARC tells receivers to act on failures and sends you visibility into who sends as your domain. Without it, spoofers can still slip through and you fly blind.
How to check
Enter your domain in the tool above. It finds the DMARC record, reads the policy and reporting addresses, and flags a missing or weak setup.
How to fix
Roll it out gradually so you don't drop real mail:
- Start with
p=noneandrua=to collect reports for a few weeks. - Fix any legitimate senders that fail SPF/DKIM.
- Move to
p=quarantine, thenp=rejectonce clean.