{
  "port": 4445,
  "protocol": "tcp",
  "service": "I2P HTTPS proxy (IANA: upnotifyp)",
  "oneLiner": "The companion to 4444 — an I2P router's HTTPS proxy, meant for localhost only.",
  "whatItIs": "IANA registers 4445 as UPNOTIFYP, which you will not encounter. In practice the port belongs to I2P: a router's HTTPS proxy tunnel listens on 4445 while the HTTP proxy uses 4444, and browsers are configured to point at both. Both are managed from the router console's i2ptunnel page and listen on the loopback interface by default. Seeing 4445 on a host almost always means an I2P router is running there.",
  "exposure": {
    "verdict": "never",
    "note": "It is a local proxy tunnel — exposing it hands strangers a route through your I2P router and deanonymises nothing but you."
  },
  "checkCommand": "nc -vz -w 3 TARGET 4445",
  "links": [
    {
      "title": "I2P FAQ — port 4445 is the router's HTTPS proxy",
      "url": "https://i2p.net/en/docs/overview/faq",
      "kind": "official-docs"
    },
    {
      "title": "IANA port registry — 4445 (upnotifyp)",
      "url": "https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=4445",
      "kind": "iana"
    }
  ]
}