Success confirms a handshake; failure does not prove closure
Browsers cannot perform arbitrary TCP scans. Certificates, proxies, firewalls, and non-WebSocket services all appear unconfirmed. Test only hosts you are authorized to inspect.
WSS Port Handshake Probe
Try secure WebSocket handshakes sequentially on up to 20 ports of a public hostname.
This is not an arbitrary TCP scanner. The browser can only try secure WebSocket handshakes; certificates, proxies, firewalls, and non-WebSocket services all produce “unconfirmed”.
Only successful WSS handshakes are confirmed; failures are never called closed ports.