{
  "port": 5811,
  "protocol": "tcp",
  "service": "Unassigned",
  "oneLiner": "No IANA registration and no common service — an open 5811 is whatever local application claimed it.",
  "whatItIs": "5811 sits in a gap of the IANA registry: 5813 (icmpd) and 5814 (spt-automation) are registered, but 5811 is not, and no mainstream product defaults to it. Under VNC's 5800+display convention it would correspond to display :11, which is rare in practice. Treat a hit here as an unknown service and identify it directly.",
  "exposure": {
    "verdict": "careful",
    "note": "An unknown listener deserves no default trust. Confirm the process and its authentication before exposing it anywhere."
  },
  "checkCommand": "sudo lsof -nP -iTCP:5811 -sTCP:LISTEN",
  "links": [
    {
      "title": "IANA port registry — 5811 (unassigned)",
      "url": "https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=5811",
      "kind": "iana"
    }
  ]
}