{
  # nxdomain numeric expression
  # empty configs are not accepted by Kea
  "Dhcp6": {
    "valid-lifetime": 1800,
    "client-classes": [
      # reduce literals
      {
        "name": "literal",
        /// from: match if (substring(option dhcp6.interface-id, 0, 393231 % 128)) = 0xabcd
        "test": "substring(option[18].hex,0,15) == 0xabcd"
      }
    ],
    "option-data": [
      # raw
      {
        "space": "dhcp6",
        "name": "interface-id",
        "code": 18,
        "csv-format": false,
//      /// constant DHCP_R_NXDOMAIN(393231)
//      /// constant S_BOUND(5)
//      "original-data": "\u0000\u0006\u0000\u0014",
        "data": "00060014"
      }
    ]
  }
}