List assigned IP addresses

curl --request GET \
  --url https://api.altostrat.io/eip/l2tp \
  --header 'Authorization: Bearer <token>'

[
  {
    "id": "f4e3d2c1-b0a9-8765-4321-fedcba098765",
    "ip": "198.51.100.15",
    "ptr": "host15.customer.com",
    "credentials": {
      "username": "eip_abc123def456",
      "password": "s3cr3tP@ssw0rd"
    },
    "connection": {
      "session_id": "sess_xyz789",
      "nas": "10.0.0.1",
      "called_station_id": "00-1A-2B-3C-4D-5E",
      "calling_station_id": "01-23-45-67-89-AB",
      "connected_at": "2025-04-07T08:30:00Z",
      "disconnected_at": null
    }
  }
]