CCNA Practice Test 9 — 10 Questions

Question 1

Why is route summarization useful at a distribution layer or area boundary?

Accepted Answer

It reduces the number of specific prefixes that must be carried or advertised.. Route summarization is useful because it reduces the number of individual routes that have to be advertised and stored. In practical terms, one summary can represent many more specific internal prefixes, which helps keep routing tables smaller and updates simpler. That improves scalability and reduces control-plane clutter.

Summarization does not eliminate the need for detail everywhere, but it helps present the network more efficiently at aggregation points.

Answer

It forces all traffic to use a default route only.

Answer

It automatically encrypts routing updates.

Answer

It removes the need for subnetting.

Question 2

Which OSI layer is responsible for end-to-end segmentation, port numbers, and reliability functions such as acknowledgments?

Accepted Answer

Transport. The Transport layer (Layer 4) is responsible for end-to-end segmentation, port numbers for identifying applications, and reliability functions like acknowledgments and retransmission. The Network layer (Layer 3) handles logical addressing and routing between networks. The Data Link layer (Layer 2) manages local frame delivery and error detection. The Session layer (Layer 5) controls dialog management and synchronization, not segmentation or ports.

Answer

Network

Answer

Data Link

Answer

Session

Question 3

In a router-on-a-stick design, what is configured on the physical router interface connected to the switch?

Accepted Answer

Subinterfaces with 802.1Q encapsulation for each routed VLAN. Router-on-a-stick uses one physical router interface with multiple logical subinterfaces. Each subinterface is associated with a VLAN using 802.1Q encapsulation and gets an IP address for that VLAN. Option A is wrong because IP addresses are configured on subinterfaces, not directly on the physical interface for all VLANs. Option B is wrong because inter-VLAN routing requires a router; the switch alone does not perform inter-VLAN routing in this design. Option D is wrong because serial encapsulation is used for WAN connections, not for VLAN tagging on Ethernet interfaces.

Answer

One IP address for every VLAN on the physical interface itself only

Answer

No subinterfaces; the switch handles all inter-VLAN routing internally

Answer

A serial encapsulation setting for each VLAN

Question 4

Which field is modified by each router hop in an IPv4 packet to prevent endless forwarding loops?

Accepted Answer

TTL. The Time to Live field is decremented at each hop.

Answer

Source port

Answer

Sequence number

Answer

CRC in the Ethernet trailer

Question 5

Which TWO statements accurately describe how AI and ML concepts are applied to network operations?

Accepted Answer

Intent-based networking translates business intent into network policies and continuously validates that the network meets those intentions.. Intent-based networking (IBN) captures business intent in a declarative model, translates it into network policies (e.g., via Cisco DNA Center), and continuously validates that the network state matches the intended outcome using assurance and closed-loop analytics. Option B is correct because anomaly detection leverages ML models to establish a baseline of normal traffic and then flags deviations, which can indicate security threats or performance issues. Option C is incorrect because predictive analytics forecasts future network conditions but does not automatically reconfigure devices; that requires closed-loop automation. Option D is false because ML models in network operations are not trained exclusively on labeled data; unsupervised learning can detect unknown patterns without labeled datasets. Option E is false because rule-based systems cannot adapt to new, unknown patterns without manual updates, whereas ML models are better suited for anomaly detection due to their ability to learn and generalize from data.

Answer

Predictive analytics uses historical data to forecast future network conditions and automatically reconfigures network devices to prevent issues.

Answer

ML models in network operations are trained exclusively on labeled datasets to detect known attack signatures.

Answer

Rule-based systems are preferred over ML for anomaly detection because they can adapt to new, unknown patterns without manual updates.

Question 6

A Layer 2 switch port connected to an end host should move to forwarding quickly but also shut down if a BPDU is received. Which pair of features best supports that design?

Accepted Answer

PortFast and BPDU Guard. PortFast and BPDU Guard are the right pair. In plain language, PortFast makes an edge port usable quickly for a real end device, while BPDU Guard protects that same port by shutting it down if spanning-tree control traffic appears unexpectedly.

This is a classic access-layer design. PortFast improves usability, and BPDU Guard improves safety. The best answer combines both functions.

Answer

Root Guard and UDLD

Answer

Loop Guard and native VLAN

Answer

Port security and EtherChannel

Question 7

An API response returns a list of interface objects in JSON. Which structure most likely represents that list?

Accepted Answer

An array containing multiple interface objects. In JSON, a list is most naturally represented as an array. In plain language, when an API needs to return several interfaces, routes, VLANs, or similar repeated items, it usually places them inside square brackets as an ordered collection. Each item inside that array might itself be an object containing keys such as name, status, or IP address.

CCNA automation questions usually test whether you recognize that square brackets signal a list. If the response contains many similar interface records, the best structure is the one that looks like a JSON array of interface objects rather than a single scalar value.

Answer

A single integer with the value 1

Answer

A native VLAN field

Answer

An STP root bridge ID

Question 8

Why is the combination of strong authentication and centralized logging better than either control by itself?

Accepted Answer

Authentication improves prevention, while centralized logging improves visibility and investigation.. The combination is better because strong authentication helps prevent unauthorized access, while centralized logging helps detect, review, and investigate what happened across the environment. In practical terms, one control is stronger on prevention, and the other is stronger on visibility and accountability. Together they provide broader protection than either one alone.

This reflects a real security principle: mature security depends on layers of control, not one mechanism trying to do every job.

Answer

They are redundant because both perform exactly the same task.

Answer

Centralized logging makes authentication unnecessary.

Answer

Strong authentication removes the need for any event records.

Question 9

Exhibit: A script sends an HTTP GET request to a controller API endpoint. What is the usual purpose of the GET method?

Accepted Answer

Retrieve information from the resource. In REST-style APIs, GET is normally used to retrieve data from a resource. It is not the standard method for creating or replacing resources.

Answer

Create a brand-new resource

Answer

Replace the entire resource configuration

Answer

Delete the resource

Question 10

A support engineer is explaining why a host uses ARP before sending a frame on an Ethernet LAN. Which two statements are correct?

Accepted Answer

ARP resolves an IPv4 address to a MAC address. On Ethernet, the sender needs a destination MAC address. For remote destinations, that usually means ARPing for the default gateway's MAC.

Answer

ARP is used to discover the remote router's OSPF router ID

Answer

ARP replaces DNS for hostname resolution