Which TLS versions should I allow in 2025+?

Prefer TLS 1.3 everywhere you can; keep TLS 1.2 only for legacy clients you must support. Disable SSLv3, TLS 1.0, and TLS 1.1 on the public internet. Document exceptions for isolated legacy integrations and isolate them on separate endpoints if possible.

What makes a cipher suite weak?

NULL or export-grade ciphers, RC4, 3DES, CBC modes paired with old TLS versions, and anonymous key exchange. Modern stacks should offer AEAD suites (AES-GCM, ChaCha20-Poly1305) with forward secrecy (ECDHE). Scan results should flag anything outside that baseline.

What were BEAST, POODLE, and Heartbleed?

BEAST exploited TLS 1.0 CBC timing in browsers; mitigation was protocol upgrades. POODLE attacked SSLv3 padding—turn SSLv3 off. Heartbleed was an OpenSSL buffer over-read leaking memory; fix was patching OpenSSL and rotating keys/certs. Scanners still test for echoes of these patterns in misconfigurations.

Why is TLS 1.3 considered better?

It removes obsolete algorithms, mandates forward secrecy for most handshakes, cuts round trips (1-RTT and 0-RTT where used), and encrypts more of the handshake. Attack surface shrinks because negotiable legacy options disappear.

Does a good TLS scan replace certificate monitoring?

No. Scanners evaluate protocol and cipher posture; certificates have their own lifecycle (expiry, chain, SANs). Use the [SSL certificate checker](/ssl-certificate) for trust and identity, and this scanner for protocol hygiene.

TLS Checker

v1.0.0

Test a domain’s TLS configuration for protocol support, cipher strength, certificate validity, and handshake security. Get detailed insights to prevent browser warnings and ensure secure HTTPS communication.

TLS scan results will appear here

Assess live TLS: supported versions, cipher suites, and classic misconfiguration patterns. Use it to align your HTTPS endpoint with current best practice without maintaining your own SSL Labs–style lab.

Read the full guide →

Frequently Asked Questions

Which TLS versions should I allow in 2025+?: Prefer TLS 1.3 everywhere you can; keep TLS 1.2 only for legacy clients you must support. Disable SSLv3, TLS 1.0, and TLS 1.1 on the public internet. Document exceptions for isolated legacy integrations and isolate them on separate endpoints if possible.
What makes a cipher suite weak?: NULL or export-grade ciphers, RC4, 3DES, CBC modes paired with old TLS versions, and anonymous key exchange. Modern stacks should offer AEAD suites (AES-GCM, ChaCha20-Poly1305) with forward secrecy (ECDHE). Scan results should flag anything outside that baseline.
What were BEAST, POODLE, and Heartbleed?: BEAST exploited TLS 1.0 CBC timing in browsers; mitigation was protocol upgrades. POODLE attacked SSLv3 padding—turn SSLv3 off. Heartbleed was an OpenSSL buffer over-read leaking memory; fix was patching OpenSSL and rotating keys/certs. Scanners still test for echoes of these patterns in misconfigurations.
Why is TLS 1.3 considered better?: It removes obsolete algorithms, mandates forward secrecy for most handshakes, cuts round trips (1-RTT and 0-RTT where used), and encrypts more of the handshake. Attack surface shrinks because negotiable legacy options disappear.
Does a good TLS scan replace certificate monitoring?: No. Scanners evaluate protocol and cipher posture; certificates have their own lifecycle (expiry, chain, SANs). Use the [SSL certificate checker](/ssl-certificate) for trust and identity, and this scanner for protocol hygiene.