{
  "id": "04",
  "content": [
    {
      "type": "heading",
      "text": "DNS, TTL and Cutover Planning"
    },
    {
      "type": "text",
      "html": "DNS cutover should be planned, not improvised. Know which records change, what the old values are, what the new values are, and how long caches may keep old answers."
    },
    {
      "type": "text",
      "html": "Lowering TTL before launch can make changes easier to recover from. It is not instant, because existing caches need time to expire."
    },
    {
      "type": "text",
      "html": "DNS work should include root and www, mail records, verification TXT records, and any app subdomains that must keep working."
    },
    {
      "type": "callout",
      "style": "info",
      "html": "<strong>Practice:</strong> Create a DNS change sheet with old record, new record, TTL, reason, owner, validation step, and rollback value."
    }
  ],
  "quiz": {
    "questions": [
      {
        "id": "q1",
        "type": "single",
        "text": "Why plan DNS cutover?",
        "options": [
          {
            "id": "a",
            "text": "To know what changes and how to roll back"
          },
          {
            "id": "b",
            "text": "To make changes invisible"
          },
          {
            "id": "c",
            "text": "To avoid documenting records"
          }
        ],
        "correct": [
          "a"
        ]
      },
      {
        "id": "q2",
        "type": "single",
        "text": "What can lower TTL help with?",
        "options": [
          {
            "id": "a",
            "text": "Faster recovery from planned DNS changes"
          },
          {
            "id": "b",
            "text": "Stronger passwords"
          },
          {
            "id": "c",
            "text": "Better image compression"
          }
        ],
        "correct": [
          "a"
        ]
      }
    ]
  }
}