{
  "port": 1999,
  "protocol": "tcp",
  "service": "Cisco identification port",
  "oneLiner": "Registered to Cisco as an identification port; rarely seen in the wild.",
  "whatItIs": "IANA lists 1999 as tcp-id-port, \"cisco identification port\", registered by Cisco Systems. There is no public protocol specification for it and it is not a service you deliberately turn on. In practice a listener here is either a Cisco device or, more often, an unrelated application that grabbed a round number just below 2000.",
  "exposure": {
    "verdict": "careful",
    "note": "Nothing well documented runs here, so treat an open 1999 as an unidentified listener: fingerprint it before deciding, and do not expose an unknown service to the internet."
  },
  "checkCommand": "nc -vz TARGET 1999",
  "links": [
    {
      "title": "IANA port registry — 1999 (tcp-id-port)",
      "url": "https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=1999",
      "kind": "iana"
    }
  ]
}