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DMARC generator

Build a v=DMARC1; … TXT record. Paste the output into your DNS provider as a TXT record at _dmarc.<your-domain>.

Domain (for the host field)

Policy (p=)

Subdomain policy (sp=, optional)

Only emit if it differs from the main policy.

Pct (% of mail subject to policy)

100 is the default and is omitted from the record. Use lower values to phase in.

Reporting address (rua=, optional)

Aggregate reports go here. Use a dedicated mailbox or a reporting service.

Generated record

v=DMARC1; p=none

DNS record

Type	TXT
Host	`_dmarc`
Value	`v=DMARC1; p=none`
TTL	3600 (1 hour)

💡 You're in monitoring mode. Run for 2–4 weeks, watch the rua reports for legitimate sources, then tighten to quarantine and finally reject.

What is DMARC?

DMARC (Domain-based Message Authentication, Reporting and Conformance) ties SPF and DKIM together: it tells receivers what to do when a message claiming to be from your domain fails authentication, and asks them to send aggregate reports back so you can monitor abuse.

Always start with p=none for at least two weeks. Once you've confirmed (via the rua reports) that all legitimate senders are aligned, move to p=quarantine, then eventually p=reject.