{
  "port": 6,
  "protocol": "both",
  "service": "Unassigned",
  "oneLiner": "Unassigned at IANA — no registered service, no common squatter.",
  "whatItIs": "IANA lists port 6 as Unassigned on both TCP and UDP. It has no assignee, no reference document, and no daemon that binds it as a default. The number is easy to confuse with IP protocol number 6, which is TCP itself, but that is a different registry entirely. A listener here is bespoke, and identifying the owning process is the only reliable step.",
  "exposure": {
    "verdict": "careful",
    "note": "Unregistered, so an open port 6 tells you nothing on its own; name the process before judging exposure."
  },
  "checkCommand": "sudo lsof -nP -iTCP:6 -sTCP:LISTEN",
  "links": [
    {
      "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"
    }
  ]
}