SSL & Security

TLS Checker

Versions & Ciphers

Check TLS configuration

Enter a domain name and port to analyze SSL/TLS configuration, protocol versions, and security settings.

Tool features

Comprehensive TLS/SSL analysis with security grading and recommendations
4 checks

TLS Version Detection

Identify supported TLS/SSL protocol versions

Security Analysis

Comprehensive security assessment with grades

Certificate Details

SSL certificate information and validation

Performance Metrics

TLS handshake timing and cipher strength

What is TLS & how it works

Protocol versions and cipher suites behind every HTTPS connection

TLS (Transport Layer Security) is the protocol that encrypts the connection between a browser and a server. Every HTTPS request negotiates a TLS version and a cipher suite during the handshake — and the exact combination a server accepts determines whether the connection is fast, private, and resistant to downgrade or interception attacks.

This checker probes which protocol versions a server offers (from the obsolete SSL 3.0 up to the current TLS 1.3), inspects the negotiated cipher suites, and flags weak or deprecated settings. Keeping TLS 1.2 and 1.3 enabled while disabling older versions is a baseline requirement for security standards such as PCI DSS and for avoiding browser warnings.

TLS 1.3
The latest protocol version — faster handshakes, forward secrecy by default, and no legacy weak ciphers.
Cipher suite
The agreed set of algorithms for key exchange, encryption, and integrity used for a connection.
Downgrade attack
An attempt to force a connection onto an older, weaker protocol. Disabling TLS 1.0/1.1 closes the door on it.

How to use this tool

Analyze a server's TLS configuration in four steps
1
Enter a domain and port
Type the hostname and the port to probe (443 for HTTPS, or a custom TLS port).
2
Run the TLS check
We negotiate handshakes to detect every protocol version and cipher the server accepts.
3
Review versions and ciphers
See which TLS versions are enabled and whether any weak or deprecated ciphers are offered.
4
Harden the configuration
Disable SSL 3.0 / TLS 1.0 / 1.1, keep TLS 1.2 and 1.3, and prefer strong cipher suites.

Related tools

Keep debugging with tools from the same suite
4 tools
SSL Checker
Comprehensive SSL certificate analysis including validity, expiration, chain verification, TLS versions, and security assessment
SSL Scanner
Advanced SSL/TLS security scanner with comprehensive vulnerability assessment and configuration analysis
HSTS Checker
Check HTTP Strict Transport Security (HSTS) header configuration and preload status
Secure Header Checker
Check security headers like CSP, HSTS, X-Frame-Options, and more with security scoring

Frequently asked questions

Common questions about TLS version checks
5 Q&A

TLS 1.2 and TLS 1.3 are secure and should be enabled. SSL 3.0, TLS 1.0 and TLS 1.1 are deprecated, fail modern compliance checks, and should be disabled.

An SSL/certificate checker focuses on the certificate — issuer, expiry, and chain. This TLS checker focuses on the protocol layer — which versions and cipher suites the server negotiates.

TLS 1.3 removes legacy weak ciphers, enforces forward secrecy, and completes the handshake in fewer round trips — so connections are both more secure and faster.

A cipher suite is the bundle of algorithms negotiated for a connection: key exchange, bulk encryption, and message integrity. Weak suites (e.g. those using RC4 or 3DES) should be removed.

Very old browsers and devices that only support TLS 1.0/1.1 may fail to connect, but these represent a tiny, insecure share of traffic and are already blocked by most major services.