{
  "port": 1039,
  "protocol": "both",
  "service": "sbl (Streamlined Blackhole)",
  "oneLiner": "Registered in 2004 as \"Streamlined Blackhole\"; no specification was ever published.",
  "whatItIs": "IANA assigns 1039 to `sbl`, \"Streamlined Blackhole\", registered in November 2004 to an individual with no reference document attached. Despite the name's resemblance to the Spamhaus SBL blocklist, the registry gives no relationship between the two and no protocol description, so nothing further can be stated honestly. In practice an open 1039 is another low-range dynamic port, commonly an RPC endpoint on Windows systems predating Vista.",
  "exposure": {
    "verdict": "careful",
    "note": "Undocumented registration; the port number gives you no information, so identify the process behind any open 1039."
  },
  "checkCommand": "nc -vz TARGET 1039",
  "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"
    }
  ]
}