{
  "port": 4129,
  "protocol": "tcp",
  "service": "NuFW authentication server (nuauth)",
  "oneLiner": "nuauth, the authentication daemon of the NuFW identity-aware Linux firewall.",
  "whatItIs": "NuFW extends Netfilter with per-user authentication: the packet-filtering side queues a connection and asks nuauth whether the user behind it is allowed, and clients authenticate to nuauth over TCP 4129. IANA assigned 4128 to nufw and 4129 to nuauth in 2007. The project has seen no significant development in over a decade, so this is a legacy sighting on older Linux gateways.",
  "exposure": {
    "verdict": "never",
    "note": "It is the decision point of a firewall's authorisation policy on unmaintained code — reachable only from the client networks it authenticates, never the public internet."
  },
  "checkCommand": "nc -vz -w 3 TARGET 4129",
  "links": [
    {
      "title": "regit/nufw",
      "url": "https://github.com/regit/nufw",
      "kind": "github"
    },
    {
      "title": "IANA port registry — 4129 (nuauth)",
      "url": "https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=4129",
      "kind": "iana"
    }
  ]
}