CCNA Network Services and Security Practice Question
This 200-301 practice question tests your understanding of network services and security. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. A key principle to apply: dNS resolves human-readable hostnames into IP addresses to enable network communication using names instead of numeric IPs.. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
What is the primary function of DNS?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "primary"
Why it matters: Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
To map hostnames to IP addresses
DNS resolves hostnames to IP addresses and can also support reverse lookups and other naming records. It is a foundational naming service for IP networks.
Key principle: DNS resolves human-readable hostnames into IP addresses to enable network communication using names instead of numeric IPs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
The clue word "primary" in the question point toward this answer.
Related concept
DNS resolves human-readable hostnames into IP addresses to enable network communication using names instead of numeric IPs.
✗
To translate MAC addresses into switchport numbers
Why it's wrong here
Switchport mappings are handled through switching and management data, not DNS.
When this WOULD be correct
If the exam question asked about the function of a network device like a switch that translates MAC addresses into switchport numbers for forwarding decisions, then this option would be correct.
✗
To assign default gateways to hosts
Why it's wrong here
Default gateways are typically learned through DHCP or static configuration.
When this WOULD be correct
This option would be correct in a question asking about DHCP (Dynamic Host Configuration Protocol) functions, where the question specifies that DHCP assigns IP addresses and default gateways to hosts on a network.
If the exam question asked about the functions of network protocols in a Layer 2 switching context, specifically focusing on STP, then this option would be correct as it pertains to maintaining topology information for preventing loops in a switched network.
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.
✓To map hostnames to IP addressesCorrect answer▾
Why this is correct
Correct. DNS provides name resolution.
✗To translate MAC addresses into switchport numbersWrong answer — click to see why▾
Why this is wrong here
This option is wrong because DNS does not deal with MAC addresses or switchport numbers; it is specifically designed to resolve hostnames to IP addresses.
★ When this WOULD be the correct answer
If the exam question asked about the function of a network device like a switch that translates MAC addresses into switchport numbers for forwarding decisions, then this option would be correct.
Why candidates choose this
Candidates may confuse the roles of different networking protocols and devices, leading them to mistakenly associate DNS with MAC address translation due to their general understanding of network operations.
✗To assign default gateways to hostsWrong answer — click to see why▾
Why this is wrong here
This option is wrong because DNS (Domain Name System) does not assign default gateways; instead, it resolves domain names to IP addresses. Default gateways are configured on hosts to route traffic outside their local subnet.
★ When this WOULD be the correct answer
This option would be correct in a question asking about DHCP (Dynamic Host Configuration Protocol) functions, where the question specifies that DHCP assigns IP addresses and default gateways to hosts on a network.
Why candidates choose this
Candidates may choose this option due to confusion between DNS and DHCP functions, as both are essential for network configuration and management, leading to a mix-up in their roles.
✗To maintain STP topology informationWrong answer — click to see why▾
Why this is wrong here
This option is wrong because the primary function of DNS is to resolve hostnames to IP addresses, not to maintain Spanning Tree Protocol (STP) topology information, which is related to network switching.
★ When this WOULD be the correct answer
If the exam question asked about the functions of network protocols in a Layer 2 switching context, specifically focusing on STP, then this option would be correct as it pertains to maintaining topology information for preventing loops in a switched network.
Why candidates choose this
Candidates may choose this option due to a misunderstanding of network protocols, confusing the roles of DNS and STP, especially if they have encountered both in their studies but have not clearly differentiated their functions.
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?”
Common exam traps
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is mistaking DNS for protocols or services that handle hardware address resolution or routing information. For instance, some candidates incorrectly associate DNS with MAC address translation or default gateway assignment, which are functions of ARP and DHCP respectively. Another trap is confusing DNS with Spanning Tree Protocol (STP), which manages Layer 2 topology and has no role in name resolution. This confusion arises because all these protocols are fundamental to network operations but serve distinct purposes. Recognizing that DNS exclusively resolves hostnames to IP addresses helps avoid these pitfalls and ensures correct answer selection.
Detailed technical explanation
How to think about this question
The Domain Name System (DNS) is a hierarchical and decentralized naming system used to translate human-friendly domain names into IP addresses, which are necessary for locating and identifying devices on IP networks. DNS operates as a distributed database that resolves hostnames like www.example.com into IPv4 or IPv6 addresses, enabling users and applications to access resources without memorizing numeric IP addresses.
In Cisco networking and the CCNA context, DNS is critical for IP services because it allows devices and applications to resolve names dynamically, supporting both forward lookups (hostname to IP) and reverse lookups (IP to hostname). Cisco IOS devices can be configured to use DNS to resolve names for management and troubleshooting commands, enhancing network usability. The DNS process involves querying DNS servers, which may be local or remote, to obtain the necessary IP address mappings.
A common exam trap is confusing DNS with other network functions such as MAC address resolution or routing configuration. For example, Address Resolution Protocol (ARP) resolves IP addresses to MAC addresses, not DNS. Similarly, DHCP assigns IP addresses and default gateways but does not perform name resolution. Understanding that DNS strictly maps hostnames to IP addresses prevents misinterpretation of its role in IP services and avoids selecting incorrect options related to switching or routing protocols.
KKey Concepts to Remember
DNS resolves human-readable hostnames into IP addresses to enable network communication using names instead of numeric IPs.
Cisco devices use DNS to translate domain names for management commands and application connectivity within IP networks.
DNS supports both forward lookups (hostname to IP) and reverse lookups (IP to hostname) to facilitate flexible name resolution.
DNS operates independently from ARP, which resolves IP addresses to MAC addresses at Layer 2 for local network communication.
DHCP assigns IP addresses and default gateway information but does not perform hostname to IP address resolution like DNS.
STP manages Layer 2 network topology and does not participate in IP name resolution or address mapping functions.
DNS queries are sent to configured DNS servers, which respond with the IP address corresponding to the requested hostname.
Understanding DNS’s role prevents confusion with other protocols and ensures accurate configuration and troubleshooting in Cisco networks.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
DNS resolves human-readable hostnames into IP addresses to enable network communication using names instead of numeric IPs.
Real-world example
How this comes up in practice
A help-desk technician troubleshoots why a newly connected PC cannot reach shared printers on the same floor. The cable is good, the switch port is active, but the PC is in VLAN 20 and the printers are in VLAN 10. The uplink trunk only allows VLAN 10. A trunk being up does not mean every VLAN crosses it.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 200-301 question in full detail.
Review dNS resolves human-readable hostnames into IP addresses to enable network communication using names instead of numeric IPs., then practise related 200-301 questions on the same topic to reinforce the concept.
Network Services and Security — This question tests Network Services and Security — DNS resolves human-readable hostnames into IP addresses to enable network communication using names instead of numeric IPs..
What is the correct answer to this question?
The correct answer is: To map hostnames to IP addresses — DNS resolves hostnames to IP addresses and can also support reverse lookups and other naming records. It is a foundational naming service for IP networks.
What should I do if I get this 200-301 question wrong?
Review dNS resolves human-readable hostnames into IP addresses to enable network communication using names instead of numeric IPs., then practise related 200-301 questions on the same topic to reinforce the concept.
Are there clue words in this question I should notice?
Yes — watch for: "primary". Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
What is the key concept behind this question?
DNS resolves human-readable hostnames into IP addresses to enable network communication using names instead of numeric IPs.
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