{
  "port": 5298,
  "protocol": "both",
  "service": "XMPP link-local messaging (presence)",
  "oneLiner": "Serverless XMPP between machines on the same LAN — the old Bonjour/iChat-style chat.",
  "whatItIs": "IANA registered 5298 in 2008 as presence, for XMPP link-local messaging: peers advertise _presence._tcp over mDNS and then open a direct XMPP stream to each other with no server in the middle, as described in XEP-0174. Apple's iChat/Messages Bonjour mode popularised it, and Pidgin and Gajim implement the same scheme. Seeing it means a desktop chat client with local discovery turned on, not a chat server.",
  "exposure": {
    "verdict": "careful",
    "note": "Link-local by design and unauthenticated — fine on a trusted LAN, and it has no business being routed or forwarded anywhere."
  },
  "checkCommand": "dns-sd -B _presence._tcp local.",
  "links": [
    {
      "title": "XEP-0174 — Serverless Messaging",
      "url": "https://xmpp.org/extensions/xep-0174.html",
      "kind": "spec"
    },
    {
      "title": "IANA port registry — 5298 (presence)",
      "url": "https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=5298",
      "kind": "iana"
    }
  ]
}