Probes protocol-level reachability and round-trip latency across 16
protocols: TCP, UDP, DNS, HTTP, HTTPS, WebSocket (ws/wss), MQTT
(mqtt/mqtts, 3.1.1 + v5), gRPC (Health.Check + Health.Watch), HLS,
TLS handshake, NTP, STUN, TURN, RTSP (rtsp/rtsps), RTMP (rtmp/rtmps),
and QUIC / HTTP/3. Activates when the user asks about latency, RTT,
reachability, "is X alive", TLS cert / handshake timing, ALPN
agreement, gRPC health, MQTT broker liveness, STUN / TURN / WebRTC
infra, RTSP / RTMP streaming ingest, HTTP/3 handshake, multi-region
comparison, or DNS resolver comparison. Each ping measures the real
protocol-level exchange — not just whether a TCP socket opens.
Provides an MCP server (`knockknock-mcp`, preferred for agents —
structured JSON output) and a CLI binary (`knockknock`).
2026-05-01