TLS checker
See which TLS versions and ciphers a server accepts.
What the result shows
Obsolete: browsers dropped them in 2020. "Yes (outdated)" means the server should turn them off; "No (good)" means it already has.
TLS 1.2 is what every client needs; TLS 1.3 is faster and safer. The table shows the cipher the server picks for each.
Whether the server still accepts NULL or anonymous ciphers (no real protection), or picks a TLS 1.2 cipher without forward secrecy.
Some firewalls silently drop old versions instead of refusing them; then the tool says so rather than guessing.
It opens a few short connections to port 443 of the domain, only if it points to a public address, and stores nothing. It sees what the address answering for the domain offers: a CDN or load balancer may differ from the server behind it. It doesn't list every cipher suite.