CCNA Network Services and Security Practice Question
Which two statements accurately describe DNS in normal network operation?
⚠ Common exam trap
A frequent exam trap is mistaking DNS for DHCP or routing protocols. Some candidates incorrectly believe DNS dynamically assigns IP addresses like DHCP or that it replaces the need for default gateways. This confusion arises because both DNS and DHCP are IP services but serve fundamentally different roles. DNS strictly resolves hostnames to IP addresses and does not handle IP address allocation or routing decisions. Misinterpreting DNS’s function can lead to selecting incorrect answers that describe DHCP’s role or routing concepts, which do not apply to DNS.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
DNS helps resolve hostnames into IP-related information.
Option A is correct because DNS (Domain Name System) performs name resolution, translating human-readable hostnames such as www.example.com into IP-related information like A records (IPv4 addresses) and AAAA records (IPv6 addresses). Option B is correct because this name-to-address mapping lets users reference hosts by meaningful names instead of memorizing raw IP addresses, which is the core usability benefit of DNS in normal network operation. Option C is incorrect because dynamic IP address assignment is the function of DHCP (Dynamic Host Configuration Protocol), not DNS, which resolves names rather than leasing addresses. Option D is incorrect because default gateways are configured on hosts to route traffic off the local subnet, and DNS does not replace that routing function. Option E is incorrect because the Spanning Tree Protocol (STP, IEEE 802.1D) prevents Layer 2 loops on switches and VLAN trunks, and has nothing to do with DNS.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
DNS helps resolve hostnames into IP-related information.
Why this is correct
DNS operates as a distributed hierarchical database that maps human-readable hostnames to IP addresses via A and AAAA records, plus reverse lookups. This name-to-address resolution is the core function enabling clients to reach hosts without knowing their numeric addresses.
- ✓
DNS makes networks easier for humans to use by allowing names instead of raw IP addresses.
Why this is correct
DNS resolves human-readable hostnames into IP addresses, so users reach services by name rather than memorising numeric addresses. This directly satisfies the stem's requirement that DNS eases network use for humans, operating as the distributed hierarchical naming system queried before any connection is established.
- ✗
DNS dynamically assigns host IP addresses like DHCP.
Why it's wrong here
DNS resolves names to IP addresses; it does not allocate addresses to hosts, which is DHCP's function. It is tempting because both protocols are commonly deployed together and both involve IP addresses, but DNS maps names while DHCP leases addresses.
When this WOULD be correct
If the exam question were to ask about network services that provide IP address assignments to devices on a network, then this option would be correct. For example, a question could state, 'Which protocol is responsible for dynamically assigning IP addresses to clients in a network?'
- ✗
DNS replaces the need for default gateways.
Why it's wrong here
DNS resolves hostnames to IP addresses; it performs no forwarding decision, so it cannot replace a default gateway, which handles traffic destined off-subnet. DNS would be the correct answer where the requirement is name resolution rather than path selection. Gateways and DNS servers operate at different layers and serve distinct functions.
When this WOULD be correct
If the exam question were to ask about the roles of various network protocols in a routing context, a statement might be framed to imply that DNS can serve as a default gateway in a specific network architecture, perhaps in a hypothetical scenario where DNS is integrated with routing functionalities.
- ✗
DNS is the spanning-tree protocol used on VLAN trunks.
Why it's wrong here
DNS resolves names to IP addresses; it has no role in loop prevention on VLAN trunks, which is handled by Spanning Tree Protocol (802.1D/RSTP). The option is tempting because both are common Layer 2/3 topics, but DNS operates at the application layer for name resolution, not frame forwarding.
When this WOULD be correct
If the exam question asked about network protocols and their functions in managing VLANs, specifically in the context of preventing broadcast storms or ensuring loop-free topologies, then option E could be correct. For example, a question could ask which protocol is responsible for maintaining a loop-free network in a VLAN environment.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓DNS helps resolve hostnames into IP-related information.Correct answer▾
Why this is correct
DNS operates as a distributed hierarchical database that maps human-readable hostnames to IP addresses via A and AAAA records, plus reverse lookups. This name-to-address resolution is the core function enabling clients to reach hosts without knowing their numeric addresses.
✗DNS dynamically assigns host IP addresses like DHCP.Wrong answer — click to see why▾
Why this is wrong here
This option is incorrect because DNS (Domain Name System) is responsible for resolving domain names to IP addresses, not for dynamically assigning IP addresses to hosts, which is the function of DHCP (Dynamic Host Configuration Protocol).
★ When this WOULD be the correct answer
If the exam question were to ask about network services that provide IP address assignments to devices on a network, then this option would be correct. For example, a question could state, 'Which protocol is responsible for dynamically assigning IP addresses to clients in a network?'
Why candidates choose this
Candidates may confuse DNS with DHCP due to their complementary roles in network management, leading them to mistakenly believe that DNS also handles IP address assignments.
✗DNS replaces the need for default gateways.Wrong answer — click to see why▾
Why this is wrong here
DNS does not replace the need for default gateways; instead, it functions as a naming system that translates domain names into IP addresses. Default gateways are essential for routing traffic outside a local network, which is unrelated to DNS functionality.
★ When this WOULD be the correct answer
If the exam question were to ask about the roles of various network protocols in a routing context, a statement might be framed to imply that DNS can serve as a default gateway in a specific network architecture, perhaps in a hypothetical scenario where DNS is integrated with routing functionalities.
Why candidates choose this
Candidates may confuse DNS with other network services that manage traffic flow, leading them to mistakenly believe that DNS could serve as a default gateway due to its role in facilitating network communication.
✗DNS is the spanning-tree protocol used on VLAN trunks.Wrong answer — click to see why▾
Why this is wrong here
Option E is incorrect because DNS (Domain Name System) is not related to the spanning-tree protocol, which is used to prevent loops in network topologies, particularly in VLANs. DNS is focused on resolving domain names to IP addresses, not on managing VLAN traffic.
★ When this WOULD be the correct answer
If the exam question asked about network protocols and their functions in managing VLANs, specifically in the context of preventing broadcast storms or ensuring loop-free topologies, then option E could be correct. For example, a question could ask which protocol is responsible for maintaining a loop-free network in a VLAN environment.
Why candidates choose this
Candidates may find option E tempting because it includes technical terminology related to networking, and they might confuse the roles of different protocols, mistakenly associating DNS with VLAN management due to their familiarity with both concepts.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Visual reference
Quick reference
Routing Protocol Comparison
| Protocol | Metric | Max Hops | Algorithm | Type |
|---|---|---|---|---|
| RIP v2 | Hop count | 15 | Bellman-Ford | Distance vector |
| OSPF | Cost (bandwidth) | Unlimited | Dijkstra (SPF) | Link state |
| EIGRP | Composite metric | Unlimited | DUAL | Hybrid |
| IS-IS | Cost | Unlimited | Dijkstra | Link state |
| BGP | Policy / attributes | Unlimited | Path vector | Path vector |
RIP's 15-hop limit makes it unsuitable for large networks. OSPF and EIGRP dominate modern enterprise deployments.
Go deeper
Related to this question
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Troubleshoot: IPv6 Connectivity Issues
Key term
Domain Name System
The Domain Name System (DNS) is the internet's phonebook that translates human-friendly domain names like google.com into computer-friendly IP addresses like 172.217.0.46.
Key term
DNS
DNS is the system that translates human-friendly domain names like example.com into machine-readable IP addresses so computers can find each other on a network.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-301 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 200-301 exam.