MCQs

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1. What does an iterative lookup in DNS entail?
   a. The DNS server fully resolves the query for the client
   b. The DNS server provides the answer directly without any referrals
   c. The DNS server refers the client to another DNS server if it cannot answer
   d. The client gets the answer only if it is cached locally
   Answer: ctechtarget+1
2. In iterative DNS queries, who is responsible for continuing the query after a referral?
   a. The original client
   b. The first DNS server
   c. The authoritative server
   d. The root server
   Answer: aioriver+1
3. What is the primary difference between recursive and iterative DNS queries?
   a. Iterative queries return final answers
   b. Recursive queries use referrals
   c. Recursive queries fully resolve the address for the client
   d. Iterative queries do not use caching
   Answer: ccbtnuggets+1
4. Which DNS server typically gives the first referral in an iterative lookup?
   a. Authoritative server
   b. Recursive resolver
   c. Root server
   d. Forwarder
   Answer: cbigrock+1
5. What is provided by a DNS server during an iterative query if it cannot resolve the request?
   a. An error message
   b. A referral to another DNS server
   c. No response
   d. The final IP address regardless of authority
   Answer: btechtarget+1
6. Iterative DNS queries are particularly effective in which networking scenario?
   a. When minimizing client-side workload
   b. To reach unknown or new domain names
   c. When only internal DNS resolution is required
   d. When authoritative answers are always cached
   Answer: bbigrock+1
7. What component handles iterative lookups in most modern DNS networks?
   a. The DNS client directly
   b. Root DNS server
   c. Authoritative DNS server
   d. The recursive resolver
   Answer: dcbtnuggets+1
8. During iterative DNS lookup, what does the client do after receiving a referral?
   a. It stops the lookup
   b. It queries the next referred DNS server
   c. It waits for recursive resolution
   d. It requests cache refresh
   Answer: bomnisecu+1
9. Which of the following statements describes iterative DNS queries correctly?
   a. They provide final answers directly
   b. They always involve cache-only lookups
   c. Each server queried can return a referral
   d. They never traverse the DNS hierarchy
   Answer: ctechtarget+1
10. How does iterative DNS lookup optimize server performance?
    a. By requiring one server to resolve all queries
    b. By resolving queries through full recursion
    c. By distributing workload across multiple servers
    d. By disabling caching everywhere
    Answer: cioriver+1
11. Which layer of DNS hierarchy is usually queried first in iterative lookups?
    a. Authoritative server
    b. TLD server
    c. Root server
    d. Secondary resolver
    Answer: comnisecu+1
12. What happens if an iterative DNS query reaches a server with no further knowledge of the domain?
    a. It ends the process with an error
    b. It finds the answer using recursion
    c. The server returns a referral to another authoritative zone
    d. The client must restart the whole query
    Answer: ctechtarget+1
13. What is the initial action in the DNS iterative query process?
    a. Querying the authoritative server directly
    b. Checking local cache for records
    c. Requesting the root server for a referral
    d. Broadcasting queries across the subnet
    Answer: ccbtnuggets+1
14. What is a key security consideration with iterative DNS lookups?
    a. All lookups are encrypted end-to-end
    b. DNS traffic may be intercepted and redirected
    c. Only local caching is used
    d. They are immune to DNS spoofing
    Answer: btechtarget+1
15. Which query type places higher workload on the client vs. the resolver?
    a. Recursive query
    b. Iterative query
    c. Multicast query
    d. Zone transfer query
    Answer: bdev+1
16. Which DNS server in iterative lookup ultimately provides the authoritative answer?
    a. The root server
    b. The TLD name server
    c. The authoritative name server for the requested domain
    d. The first DNS server queried
    Answer: cdev+1
17. What happens if a DNS resolver receives multiple referrals during iterative lookup?
    a. It ignores all except the first
    b. It caches only the final answer
    c. It can follow each referral until it reaches the authoritative answer
    d. It returns an error to the client
    Answer: comnisecu+1
18. Why are iterative DNS queries considered scalable for internet-wide name resolution?
    a. They concentrate load on a single server
    b. They distribute requests across the DNS infrastructure
    c. They use manual administrator intervention
    d. They support only static records
    Answer: bbigrock+1
19. Which feature is NOT characteristic of iterative DNS queries?
    a. Referral-based responses
    b. Step-by-step resolution across hierarchy
    c. Client follows referrals for further queries
    d. Resolver always gives complete answer initially
    Answer: dtechtarget+1
20. What is the purpose of caching in iterative DNS lookup?
    a. To prevent referrals between servers
    b. To store direct answers for efficiency
    c. To enable step-by-step resolution
    d. To replace referrals permanently
    Answer: bioriver+1
21. Which DNS record is most commonly sought in iterative lookup?
    a. MX record
    b. PTR record
    c. A (Address) record
    d. SPF record
    Answer: cgeeksforgeeks+1
22. Which network service relies most heavily on iterative DNS queries for external name resolution?
    a. File transfer protocol (FTP)
    b. Email (SMTP)
    c. Web browsing (HTTP/HTTPS)
    d. Network time protocol (NTP)
    Answer: ccloudflare+1
23. In iterative DNS lookup, what is the role of a root server?
    a. To provide the final IP address
    b. To give a referral to the TLD server
    c. To cache client answers forever
    d. To directly respond for all domains
    Answer: bbigrock+1
24. What mechanism does iterative DNS lookup primarily use for efficient referral?
    a. Load balancing
    b. Direct mapping
    c. Hierarchical delegation
    d. Zigzag traversal
    Answer: ctechtarget+1
25. Why are iterative DNS queries well suited for high-traffic environments?
    a. They offload work from clients
    b. They concentrate requests on a single server
    c. They allow distributed resolution across multiple servers
    d. They never use cache
    Answer: cioriver+1
26. Which scenario best illustrates an iterative DNS query sequence?
    a. Client gets answer from resolver, process ends immediately
    b. Client follows a chain of referrals to reach the authoritative server
    c. DNS server does all query steps
    d. Answers returned are always final
    Answer: bdev+1
27. What might an iterative DNS server send if it does not know the IP address of a queried domain?
    a. Direct IP result
    b. Referral to a higher-level server
    c. Negative acknowledgment
    d. Server error message only
    Answer: bomnisecu+1
28. When does an iterative DNS query stop?
    a. When the cache is refreshed
    b. When the authoritative server for the domain is reached
    c. When a non-authoritative referral appears
    d. When local lookup fails
    Answer: btechtarget+1
29. Which query method allows the client to control each lookup step across DNS hierarchy?
    a. Recursive DNS query
    b. Iterative DNS query
    c. Parallel DNS query
    d. Dynamic DNS query
    Answer: bdev+1
30. Iterative DNS queries help reduce the risk of which DNS infrastructure issue?
    a. Excessive server load
    b. Incorrect record resolution
    c. Cache pollution
    d. Server consolidation
    Answer: abigrock+1
31. Which network device generally initiates iterative DNS lookups?
    a. Internet gateway
    b. End-user client or resolver
    c. Core router
    d. Access point
    Answer: bomnisecu+1
32. Which action is NOT part of an iterative DNS lookup process?
    a. Referring the client to another DNS server
    b. Caching partial answers
    c. Final resolution by authoritative server
    d. Direct answer by root server every time
    Answer: dtechtarget+1
33. How does iterative DNS lookup support network robustness?
    a. By relying on a single point of contact
    b. By allowing clients to retry with multiple referral servers
    c. By only using static records
    d. By disabling referrals after cache hit
    Answer: bioriver+1
34. Iterative DNS queries are often used in systems that:
    a. Require zero cache usage
    b. Maintain high fault tolerance
    c. Use TCP exclusively
    d. Always avoid root server contacts
    Answer: bbigrock+1
35. What is a limitation of iterative DNS queries in modern networks?
    a. They do not support referrals
    b. They require client to handle multiple queries
    c. They always return answers in a single step
    d. They avoid hierarchical lookup completely
    Answer: bdev+1
36. What happens to cached responses in iterative DNS systems?
    a. They improve resolution speed for future queries
    b. They are never used
    c. They are only valid at the root level
    d. They replace authoritative records permanently
    Answer: aioriver+1
37. Which is an advantage of iterative DNS queries?
    a. They minimize server workload by referral chain
    b. They eliminate the need for authoritative servers
    c. They provide final answers without hierarchy
    d. They avoid all referrals
    Answer: abigrock+1
38. Client requests in iterative DNS lookup are often initiated when:
    a. The DNS cache is populated
    b. There is no prior cached record for the domain
    c. Only local records are needed
    d. All hierarchical referrals are ignored
    Answer: bomnisecu+1
39. How do iterative DNS queries handle potential server downtime?
    a. They retry queries with next available referred servers
    b. They stop all query processes immediately
    c. They revert to a recursive strategy
    d. They bypass the hierarchy
    Answer: aioriver+1
40. Which DNS query type is most effective for distributing resolution workload?
    a. Iterative query
    b. Recursive query
    c. Direct lookup query
    d. Localhost query
    Answer: acbtnuggets+1
41. What is the core principle behind iterative DNS queries’ efficiency?
    a. Centralized resolution
    b. Distributed workload with referrals
    c. Final answer at root level
    d. Elimination of TLD servers
    Answer: bbigrock+1
42. What role does the authoritative DNS server play in iterative lookup?
    a. Provides referrals only
    b. Returns the final answer for the domain
    c. Distributes queries laterally
    d. Invalidates cache entries
    Answer: bcbtnuggets+1
43. Which attribute is NOT typical of iterative DNS query resolution?
    a. Hierarchical step-by-step referral
    b. Client receives and handles referrals
    c. Cache can be utilized at each step
    d. Automatic recursion by server
    Answer: dioriver+1
44. Where are partial answers commonly cached during iterative lookup?
    a. Root DNS server only
    b. Recursive resolvers and client cache
    c. Access points exclusively
    d. Only at TLD servers
    Answer: bomnisecu+1
45. Which is a direct example of an iterative DNS query referral chain?
    a. Root server → TLD server → Authoritative name server
    b. Client → Authoritative server only
    c. Resolver → Forwarder → Localhost
    d. Client → Local cache → Router only
    Answer: acbtnuggets+1
46. When utilizing iterative DNS queries for load balancing, what is achieved?
    a. Narrower resolution paths
    b. Balanced query distribution across servers
    c. Single server resolution
    d. No support for caching
    Answer: bbigrock+1
47. For a query about www.example.com, what is the first step in iterative DNS resolution?
    a. Check authoritative server
    b. Query root DNS server for referral
    c. Ask TLD server for ideal IP
    d. Bypass all referrals
    Answer: bcbtnuggets+1
48. What best describes a referral in iterative DNS lookup?
    a. A direct answer from authoritative server
    b. A direction to a next server in the hierarchy
    c. A client-side query retry message
    d. A RESET packet in TCP/IP
    Answer: btechtarget+1
49. Why are iterative DNS queries considered flexible and reliable?
    a. They concentrate logic on a single server
    b. They enable retry opportunities and distributed resolution
    c. They disable referral chains entirely
    d. They are always client-initiated recursively
    Answer: bioriver+1
50. What does the “step-by-step” nature of iterative DNS lookup refer to?
    a. The resolver handles every query itself
    b. The client receives referrals and issues multiple queries
    c. The cache replaces all answers
    d. The process always ends at root
    Answer: btechtarget+1

1. https://www.techtarget.com/whatis/definition/iterative-DNS-query
2. https://dev.to/wallacefreitas/understanding-domain-name-system-dns-recursive-iterative-queries-with-root-level-domains-581n
3. https://www.ioriver.io/terms/iterative-dns-query
4. https://www.cbtnuggets.com/blog/technology/networking/dns-recursive-vs-iterative-lookup
5. https://www.akamai.com/glossary/what-is-recursive-dns
6. https://www.bigrock.in/blog/products/domains/recursive-vs-iterative-dns
7. https://www.omnisecu.com/tcpip/recursive-and-iterative-dns-queries.php
8. https://www.techtarget.com/searchnetworking/answer/Recursive-vs-iterative-DNS-queries-Whats-the-difference
9. https://www.geeksforgeeks.org/computer-networks/domain-name-system-dns-in-application-layer/
10. https://www.cloudflare.com/learning/dns/what-is-dns/
11. https://threat.media/definition/what-is-an-iterative-dns-query/
12. https://bunny.net/academy/dns/what-is-recursive-dns-rdns/
13. https://www.slashroot.in/difference-between-iterative-and-recursive-dns-query
14. https://testbook.com/objective-questions/mcq-on-dns–5eea6a0939140f30f369d8ff
15. https://www.scribd.com/document/437919348/CH-25-Domain-Name-System-multiple-choice-questions-and-answers-pdf-converted-docx
16. https://www.cloudflare.com/learning/dns/what-is-recursive-dns/
17. https://www.sanfoundry.com/computer-networks-questions-answers-dns/
18. https://www.youtube.com/watch?v=PS0UppB3-fg
19. https://testbook.com/question-answer/which-of-the-following-are-types-of-dns-queries–68cba6234ee924768d1166c3/amp
20. https://learn.microsoft.com/en-us/windows-server/networking/dns/queries-lookups