{
  "port": 20828,
  "protocol": "tcp",
  "service": "Unassigned",
  "oneLiner": "Unassigned, unnamed, but scanned often enough to rank high in Nmap's frequency table.",
  "whatItIs": "IANA places 20828 in the unassigned block 20811-20998. Nmap lists it as 'unknown' yet with one of the higher open-frequencies among unnamed ports in this range, meaning internet-wide scans found it open on a measurable number of hosts without ever identifying what answered. No public protocol, product default, or RFC claims it. Treat an open 20828 as an unidentified application until a version scan says otherwise.",
  "exposure": {
    "verdict": "careful",
    "note": "Unnamed but commonly-open ports attract opportunistic probing. Fingerprint the listener and apply that service's rules."
  },
  "checkCommand": "nmap -Pn -sV -p 20828 --reason TARGET",
  "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"
    },
    {
      "title": "Nmap nmap-services frequency table",
      "url": "https://github.com/nmap/nmap/blob/master/nmap-services",
      "kind": "github"
    }
  ]
}