{
  "port": 50003,
  "protocol": "tcp",
  "service": "Unassigned (dynamic range)",
  "oneLiner": "No IANA assignment, no known service — typically the third port in a hand-allocated 50000 block.",
  "whatItIs": "50003 is in the range RFC 6335 sets aside for dynamic and private use, so no registration exists and none is possible. Nmap's service database records it as unknown with a very low open-port frequency. When it does turn up it is almost always because an operator or a container compose file allocated 50000, 50001, 50002, 50003 as a contiguous block for their own services.",
  "exposure": {
    "verdict": "careful",
    "note": "Meaningless in isolation. Scan the surrounding block, identify each listener, then apply the verdict that the actual service deserves."
  },
  "checkCommand": "nmap -Pn -sV -p 50000-50010 TARGET",
  "links": [
    {
      "title": "RFC 6335 — IANA Procedures for Service Name and Transport Protocol Port Number Registry",
      "url": "https://www.rfc-editor.org/rfc/rfc6335.html",
      "kind": "spec"
    },
    {
      "title": "IANA Service Name and Transport Protocol Port Number Registry",
      "url": "https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml",
      "kind": "iana"
    }
  ]
}