SSL/TLS Grade Info
SSL Labs assigns grades from A+ to F based on your server's TLS configuration. Select a grade below to see exactly what earns or loses that rating.
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A+ Exceptional configuration
- TLS 1.2 and 1.3 only — TLS 1.0 and 1.1 disabled.
- HSTS enabled with max-age ≥ 180 days and includeSubDomains.
- No weak cipher suites; forward secrecy (ECDHE/DHE) on all connections.
- Valid certificate chain with SHA-256+ signature.
- No known vulnerabilities (BEAST, POODLE, Heartbleed, CRIME, ROBOT).
A Strong configuration
- TLS 1.2 minimum; TLS 1.3 supported.
- No critical vulnerabilities.
- Forward secrecy supported on most connections.
- Valid certificate; no SHA-1 or MD5 signatures.
B Good but improvable
- TLS 1.0 or 1.1 still enabled (deprecated protocols).
- Some cipher suites without forward secrecy still offered.
- Certificate uses SHA-1 (deprecated).
- Missing HSTS header.
C Below modern standards
- RC4 or other broken cipher suites still supported.
- Insecure renegotiation allowed.
- Very short certificate key (RSA < 2048-bit).
- TLS 1.0 still the minimum supported version.
D Serious weaknesses
- SSL 3.0 still supported (POODLE vulnerability).
- Null or anonymous cipher suites offered.
- DH parameters < 1024-bit.
F Critical failures
- Expired or untrusted certificate.
- SSL 2.0 supported.
- Known critical vulnerability exploitable remotely (e.g. Heartbleed).
- Certificate hostname mismatch.
How to use
- Run the free SSL Labs test at ssllabs.com/ssltest/ for your domain.
- Note the grade returned.
- Click that grade above to see what specifically is causing the rating and what you need to fix.
Related network tools
- HTTP Headers Decoder — inspect HSTS, CSP, and other security headers
- DNS Record Explainer — understand CAA records used to restrict certificate issuers
- Port Number Lookup — identify services running on ports 443, 8443, etc.
常见问题
- What is SSL Labs grading?
- SSL Labs (ssllabs.com/ssltest/) is a free online service by Qualys that analyses a server's TLS/SSL configuration and assigns a grade from A+ to F based on protocol support, cipher strength, certificate validity, and vulnerability exposure.
- Is this grade explainer free?
- Yes, completely free with no signup and no usage limits.
- Does my data leave my device?
- No. This is a reference page — no data is sent anywhere.