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~/tools / ssl-certificate-checker

SSL certificate checker

Is the certificate about to expire, an intermediate missing or the name wrong? Enter a host, optionally with a port (e.g. mail.example.com:993).

daniele@mikweb: ~/tools — less ssl-certificate-checker.md

Typical causes of certificate errors

  • Missing intermediate: browsers often forgive it, apps, curl and mail servers do not. Always serve the full chain (fullchain.pem).
  • Wrong name: the host is not in the certificate (SAN). Common with www or new subdomains.
  • Expired: the automatic renewal ran, but the service was not reloaded.

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: ~/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.Mail DNS checkChecks MX, reverse DNS, SPF, DMARC and MTA-STS of a domain.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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