{
  "port": 146,
  "protocol": "tcp",
  "service": "ISO-TP0",
  "oneLiner": "ISO transport class 0; the standard TPKT/TP0-over-TCP port is 102, not this one.",
  "whatItIs": "IANA registers 146 as `iso-tp0` (ISO-IP0), part of the family of registrations for running OSI transport over TCP/IP. The one that mattered is port 102, where RFC 1006 puts TPKT and TP0 — the encapsulation that ISO session-layer protocols, and later Siemens S7 industrial gear, actually use. Port 146 carries no deployed implementation. Treat it as a registry artifact and look at 102 if you are chasing real ISO-over-TCP traffic.",
  "exposure": {
    "verdict": "careful",
    "note": "Nothing standard listens here; if something does, fingerprint it — and check whether the OSI service you actually care about is on 102."
  },
  "checkCommand": "nc -vz TARGET 146",
  "links": [
    {
      "title": "RFC 1006 — ISO Transport Service on top of the TCP",
      "url": "https://www.rfc-editor.org/rfc/rfc1006.html",
      "kind": "spec"
    },
    {
      "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"
    }
  ]
}