Give two reasons why iterative DNS queries are preferred to recursive DNS queries. Explain your answer.
Try an answer before revealing the guidance below.
Key Concepts
- Iterative DNS
- Recursive DNS
- Server workload
- Scalability
- Caching
Answer Approach
- Compare who follows referrals.
- Explain why distributing lookup work protects shared DNS infrastructure.
- Consider where the results get cached.
Full Answer
Answer status: Verified against study notes. Revision notes, not an official marking scheme.
First, iterative queries let a server return a referral instead of resolving the entire name on behalf of each requester, reducing work and state at high-level servers. Second, the querying resolver can cache referrals and answers and reuse them, improving scalability and lowering future lookup latency. A local recursive resolver can still provide recursion to its clients while using iterative queries upstream.
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