CCNA Network Services and Security Practice Question

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: Translates domain names to IP addresses

  Why this is correct

  The Domain Name System acts as the internet's distributed directory, mapping human-readable fully qualified domain names like www.example.com to the numeric IP addresses needed for packet forwarding. Without this lookup, users would have to memorize and manually enter raw IPv4 or IPv6 addresses, which is impractical. DNS uses hierarchical caching servers to resolve names rapidly and efficiently.

• ✗

  DNS: Assigns IP addresses dynamically to devices on a network

  Why it's wrong here

  Dynamic IP assignment is the job of DHCP (Dynamic Host Configuration Protocol), which leases IP addresses, subnet masks, default gateways, and other parameters to clients for a set duration. DNS is a peer-to-peer name-resolution service that stores resource records; it has no mechanism for leasing or reclaiming IP addresses. So, attributing dynamic address assignment to DNS is incorrect because that service belongs exclusively to DHCP.

  When this WOULD be correct

  This option would be correct if the question asked 'Which protocol dynamically assigns IP addresses to devices on a network?' and the answer choices included DHCP, but mistakenly listed DNS as the protocol.

• ✗

  DNS: Synchronizes time across network devices

  Why it's wrong here

  Precise time synchronization across network devices is handled by NTP (Network Time Protocol), which distributes Coordinated Universal Time (UTC) to maintain accurate clocks for log correlation, authentication, and timestamping. DNS handles only name-to-address (and related) queries, and it has no protocol operations for reading or setting device clocks. Therefore, DNS cannot serve as a time-synchronization protocol.

  When this WOULD be correct

  If the question asked 'Which protocol synchronizes time across network devices?' then 'NTP' would be correct, but DNS is never used for time synchronization.

• ✗

  DNS: Manages and monitors network devices

  Why it's wrong here

  Managing and monitoring network devices—such as polling CPU, memory, interface status, and generating alerts—is the function of SNMP (Simple Network Management Protocol), whose managed objects are defined in MIBs. DNS is strictly a resolution service that translates names to IP addresses as part of application-layer lookups; it does not collect device metrics or perform management operations. Describing DNS as a network management protocol is inaccurate because that role belongs to SNMP.

  When this WOULD be correct

  In a question asking 'Which protocol is used to manage and monitor network devices?', DNS would be incorrect, but if the question were 'Which service provides name resolution for network management systems?', then DNS would be correct as it resolves hostnames of managed devices.

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.

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?”