{
  "port": 8042,
  "protocol": "tcp",
  "service": "Hadoop YARN NodeManager UI; Orthanc DICOM HTTP",
  "oneLiner": "Two well-known defaults share it: YARN's NodeManager web UI and the Orthanc DICOM server's REST API.",
  "whatItIs": "IANA assigns 8042 to FireScope Agent, which is not what you will find. In a Hadoop cluster, `yarn.nodemanager.webapp.address` defaults to `${yarn.nodemanager.hostname}:8042`, so every NodeManager serves its web UI here. In medical imaging, Orthanc's default configuration \"creates a HTTP server for the REST API that listens on the port 8042\", which is also its web interface. Context — a datacentre cluster versus a hospital or research network — tells you which one you found.",
  "exposure": {
    "verdict": "never",
    "note": "The YARN NodeManager UI exposes cluster topology, running containers and application logs with no authentication in a default install. Orthanc on 8042 fronts a store of patient DICOM images. Neither should be reachable from the internet."
  },
  "checkCommand": "curl -sI http://TARGET:8042/",
  "links": [
    {
      "title": "Apache Hadoop — yarn-default.xml (yarn.nodemanager.webapp.address, :8042)",
      "url": "https://hadoop.apache.org/docs/stable/hadoop-yarn/hadoop-yarn-common/yarn-default.xml",
      "kind": "official-docs"
    },
    {
      "title": "Orthanc Book — Configuration (HTTP server on port 8042)",
      "url": "https://orthanc.uclouvain.be/book/users/configuration.html",
      "kind": "official-docs"
    },
    {
      "title": "IANA Service Name and Transport Protocol Port Number Registry — 8042 (fs-agent)",
      "url": "https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=8042",
      "kind": "iana"
    }
  ],
  "ianaName": "fs-agent"
}