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~/tools / mail-dns-checker

Mail DNS checker

Mail not arriving or landing in spam? See at a glance which DNS records are missing.

daniele@mikweb: ~/tools — less mail-dns-checker.md

What is checked

  • MX: are there mail servers, and do they have addresses?
  • Reverse DNS (PTR): does each address point to a name that points back to the same address? Many receivers reject otherwise.
  • SPF and DMARC: present, unique, policy set?
  • MTA-STS and TLS-RPT: enforce encrypted delivery and report problems.

Privacy

The domain or address you enter is sent to this server, which runs the check. Nothing is stored; to prevent abuse a salted hash of your IP address is kept for one hour. Only public addresses are queried.

daniele@mikweb: ~/blog — ls

Related articles

Mail landing in spam: SPF, DKIM and DMARC alignment explainedSPF passes but mail still lands in spam? Why DMARC needs alignment, how to read mail headers and how to roll out SPF, DKIM and DMARC in order.
daniele@mikweb: ~/tools — ls

Tools

SPF checkerCounts the DNS lookups of your SPF record (limit: 10).DNS TTL plannerPlans the TTL reduction and the move time.Cron explainerExplains cron expressions and shows the next runs.DMARC generatorBuilds a valid DMARC record to copy.Certificate checkExpiry, chain and names of a TLS certificate.Security headersGrades HSTS, CSP and other security headers.JWT decoderShows header, claims and expiry of a JWT — in your browser only.SAML decoderDecodes SAML responses and spots typical errors.

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