{
  "port": 9011,
  "protocol": "tcp",
  "service": "Reserved (TCP); D-Star routing (UDP)",
  "oneLiner": "IANA reserves 9011/tcp and assigns 9011/udp to amateur-radio D-Star routing.",
  "whatItIs": "The registry marks 9011/tcp as Reserved — deliberately held back, not available for assignment — while 9011/udp is d-star, \"D-Star Routing digital voice+data for amateur radio\". So the interesting traffic on this number is UDP and belongs to ham radio gateways. A TCP listener on 9011 is therefore something local and unregistered; find the process.",
  "exposure": {
    "verdict": "careful",
    "note": "For a D-Star gateway the UDP side is meant to reach other gateways; a TCP listener here is unexplained until you identify it."
  },
  "checkCommand": "sudo lsof -nP -iTCP:9011 -sTCP:LISTEN",
  "links": [
    {
      "title": "IANA Service Name and Transport Protocol Port Number Registry — 9011",
      "url": "https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=9011",
      "kind": "iana"
    }
  ]
}