{
  "port": 3998,
  "protocol": "tcp",
  "service": "DNX (Distributed Nagios eXecutor)",
  "oneLiner": "DNX — the abandoned Nagios add-on that farmed check plugins out to a cluster of worker nodes.",
  "whatItIs": "IANA registers 3998 as dnx, \"Distributed Nagios Executor Service\", a port the project specifically asked for. DNX is a Nagios event-broker module plus server and client daemons: the server dequeues checks from Nagios and hands them to dnxClient worker nodes, which run the plugin and return the result, spreading check load across machines. Upstream stalled — the last SourceForge release is 0.20.1 from 2013, still labelled alpha — and Nagios' own library now points people at Mod-Gearman instead. A listener on 3998 is an old monitoring cluster nobody has migrated.",
  "exposure": {
    "verdict": "never",
    "note": "The whole point of the port is dispatching commands for worker nodes to execute, and the code has been unmaintained since 2013 — keep it strictly on the monitoring network."
  },
  "checkCommand": "nc -vz TARGET 3998",
  "links": [
    {
      "title": "Distributed Nagios eXecutor (DNX) on SourceForge",
      "url": "https://sourceforge.net/projects/dnx/",
      "kind": "official-docs"
    },
    {
      "title": "IANA port registry — 3998 (dnx)",
      "url": "https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=3998",
      "kind": "iana"
    }
  ],
  "ianaName": "dnx"
}