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What is the primary function of DNS?

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What is the primary function of DNS?

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Answer choices

Why each option matters

Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.

A

Best answer

To map hostnames to IP addresses

Correct. DNS provides name resolution.

B

Distractor review

To translate MAC addresses into switchport numbers

Switchport mappings are handled through switching and management data, not DNS.

C

Distractor review

To assign default gateways to hosts

Default gateways are typically learned through DHCP or static configuration.

D

Distractor review

To maintain STP topology information

STP topology information is unrelated to DNS.

Common exam trap

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.

Technical deep dive

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.

Related practice questions

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More questions from this exam

Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.

Question 1

A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?

Question 2

A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?

Question 3

What is the OSPF metric called?

Question 4

A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?

Question 5

A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?

Question 6

A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?

FAQ

Questions learners often ask

What does this 200-301 question test?

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?

Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.

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