What are SPF and DMARC?

SPF lists authorised sending hosts. DMARC sets a policy (p=none/quarantine/reject) based on SPF/DKIM and instructs receivers what to do if a message fails.

DKIM keys are published at ._domainkey. . Use auto-scan for typical selectors (selector1, selector2, default, s1, s2 …) or enter a selector manually.

What else matters for deliverability?

Recommended: PTR (reverse DNS) for MX hosts, A/AAAA present on MX, DMARC policy ≥ quarantine, ≤10 DNS look-ups in SPF, MTA-STS & TLS-RPT, DNSSEC, matching HELO ↔ PTR, TLS check on port 25.

Email DNS checker: MX, SPF, DKIM and DMARC

Enter a domain to view its MX, SPF and DMARC records, discovered DKIM selectors and basic configuration findings.

How to run the check

Enter a domain and select “Check”.
Review MX, SPF, DMARC and automatically discovered DKIM selectors.
Change one record at a time at your DNS provider and allow for DNS cache propagation.

How to interpret the result

MX points incoming mail to a server, SPF lists authorised senders, DKIM publishes a signing key, and DMARC defines validation and reporting policy.

Limitation: valid records do not guarantee inbox placement. PTR/HELO alignment, IP and domain reputation, message content and the receiving provider’s policy also matter.