{
  "port": 3404,
  "protocol": "tcp",
  "service": "Unassigned (registration removed)",
  "oneLiner": "A port whose registration IANA removed in 2002; it belongs to no service today.",
  "whatItIs": "The IANA registry carries an explicit \"Removed\" record for 3404 dated 2002-05-01 — the earlier assignment was withdrawn and the number was never reissued. Nmap ships no service name for it and lists it among the ports it almost never finds open. Anything listening on 3404 is an application that chose a free port, so the number itself tells you nothing about the protocol.",
  "exposure": {
    "verdict": "careful",
    "note": "An unregistered port is not inherently risky, but it is unidentified — match it to a process and judge that service, not the number."
  },
  "checkCommand": "sudo lsof -nP -iTCP:3404 -sTCP:LISTEN",
  "links": [
    {
      "title": "IANA port registry — 3404 (removed)",
      "url": "https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=3404",
      "kind": "iana"
    }
  ]
}