CCNA Practice Test 33 — 15 Questions

Question 1

A network engineer notices that the router interface GigabitEthernet0/1 is in an 'administratively down' state in the output of the show ip interface brief command, preventing connectivity to the subnet connected to that interface. What is the most likely cause?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

The shutdown command is configured on the interface.. The 'administratively down' state in the output of 'show ip interface brief' indicates that the interface has been manually disabled using the 'shutdown' command. This is a Layer 1/2 administrative state, not a protocol or connectivity issue. To bring the interface up, the 'no shutdown' command must be applied in interface configuration mode.

Answer

The interface does not have an IP address assigned.

Answer

The interface is configured with an incorrect subnet mask.

Answer

An access list is blocking traffic on the interface.

Question 2

A router learns 192.168.30.0/24 from OSPF and also has a static route to 192.168.30.0/24 with administrative distance 200. Which route is installed in the routing table while both are available?

Accepted Answer

The OSPF route. The OSPF route is installed because its default administrative distance of 110 is lower than the static route’s configured administrative distance of 200. In practical terms, the static route has been intentionally made a backup. It is present in the configuration, but it does not become active while the lower-distance OSPF route is healthy.

This is a classic floating-static design question. The important point is that route-source preference depends on administrative distance when the prefix length is the same.

Answer

The static route

Answer

Both routes equally for load balancing

Answer

Neither route, because they conflict

Question 3

A host uses the subnet mask 255.255.255.240. How many usable host addresses exist in each subnet?

Accepted Answer

14. The mask 255.255.255.240 corresponds to /28. In practical terms, that leaves 4 host bits, which gives 16 total addresses in each subnet. After subtracting the network and broadcast addresses, 14 usable hosts remain.

This is a classic host-capacity calculation and a very common subnetting pattern on the exam.

Answer

12

Answer

16

Answer

30

Question 4

Which IPv6 prefix is used for link-local addresses?

Accepted Answer

FE80::/10. IPv6 link-local addresses come from FE80::/10. They are valid only on the local link and are commonly used for neighbor discovery and routing adjacency formation.

Answer

FC00::/7

Answer

2000::/3

Answer

FF00::/8

Question 5

Which two statements accurately describe a default gateway from a host perspective?

Accepted Answer

It is the next-hop path a host uses for destinations outside the local subnet.. A default gateway is the local router or Layer 3 interface that a host uses for traffic destined beyond its own subnet. In plain language, the host uses the gateway when the destination is not local. The default gateway does not replace the host’s own IP address or subnet mask; it complements them by providing the next-hop path for remote communication.

This is a foundational host-networking concept because many connectivity issues come from misunderstanding what the gateway actually does. The two correct answers are the ones that describe remote-traffic forwarding and the local next-hop role of the gateway.

Answer

It replaces the need for a subnet mask.

Answer

It is the same thing as a DNS server.

Answer

It is used only for ARP broadcasts.

Question 6

A network engineer configures OSPF between R1 and R2, but the routers never become neighbors on GigabitEthernet0/0. Based on the exhibit, what is the most likely cause?

Accepted Answer

The OSPF interface timers do not match.. The most likely cause is a hello/dead timer mismatch. In practical terms, both routers are on the same subnet and both are trying to run OSPF in area 0, so the obvious items look correct. But OSPF does not form adjacency based on IP reachability alone. It also checks whether key interface parameters agree. Hello and dead intervals are among those required parameters.

On R1, the hello interval is 10 seconds and the dead interval is 40 seconds. On R2, the hello interval is 5 seconds and the dead interval is 20 seconds. That mismatch is enough to prevent the neighbor relationship from forming. This is a common CCNA troubleshooting pattern because the interfaces can still ping each other, which makes the failure look less obvious at first glance.

Answer

The routers are using different OSPF areas.

Answer

The routers must use the same hostname to become neighbors.

Answer

The subnet mask prevents multicast OSPF traffic.

Question 7

Which two statements accurately describe subnet masks in IPv4?

Accepted Answer

It identifies the network-versus-host split in an IPv4 address.. A subnet mask tells the host which part of the IPv4 address refers to the network and which part refers to the host. In plain language, it helps the device determine whether a destination is local or remote. That decision is essential because it affects whether the host uses ARP directly or forwards traffic to the default gateway.

The wrong answers usually attribute unrelated behaviors to the subnet mask, such as encryption or hostname resolution. The two correct answers are the ones that preserve its role in defining local scope and address structure.

Answer

It resolves hostnames into IP addresses.

Answer

It encrypts packets before they leave the host.

Answer

It replaces the need for a default gateway.

Question 8

A router interface is configured with the prefix 2001:db8:acad:12::/64 and uses EUI-64 to build the interface ID. What is the main purpose of EUI-64 in this context?

Accepted Answer

It automatically creates the interface ID portion of the IPv6 address from the MAC address.. EUI-64 is used to automatically generate the interface identifier portion of the IPv6 address from the underlying MAC address. In practical terms, the /64 prefix provides the network portion, and EUI-64 helps derive the lower 64 bits without the administrator manually typing a full host portion. This can make addressing easier in environments where automatic formation is desired.

The important idea is that EUI-64 affects the interface ID, not the prefix length or the routing behavior of the network. It is an address-construction method, not a routing protocol.

Answer

It changes the /64 prefix into a /48 prefix for summarization.

Answer

It replaces the need for a link-local address.

Answer

It encrypts IPv6 traffic between neighbors.

Question 9

Which two statements accurately describe the role of a switch MAC address table?

Accepted Answer

It maps learned MAC addresses to switch ports for local forwarding decisions.. A switch MAC address table helps the switch make local forwarding decisions efficiently. In plain language, the switch learns which MAC addresses appear on which ports and then uses that information to send frames only where they need to go instead of flooding every frame everywhere.

The MAC table is not the same thing as a routing table, and it is not used for OSPF neighbor storage or DHCP lease records.

Answer

It stores the best Layer 3 routes to remote networks.

Answer

It contains the router’s OSPF authentication keys.

Answer

It assigns IP addresses to end hosts dynamically.

Question 10

A host address is 10.100.12.94/26. Which address is the broadcast address for that subnet?

Accepted Answer

10.100.12.127. A /26 subnet has a block size of 64, so the fourth-octet ranges are 0–63, 64–127, 128–191, and 192–255. The host address 10.100.12.94 lies in the 64–127 range, making the broadcast address the last address in that range: 10.100.12.127. Option A (10.100.12.63) is the broadcast of the previous subnet (0–63). Option C (10.100.12.64) is the network address of the subnet containing the host. Option D (10.100.12.128) is the network address of the next subnet (128–191).

Answer

10.100.12.63

Answer

10.100.12.64

Answer

10.100.12.128

Question 11

What is an autonomous system in basic BGP terminology?

Accepted Answer

A collection of networks and routers under common administrative routing control. An autonomous system is a collection of IP networks and routers under a common routing policy or administrative control. In practical terms, it is the domain boundary concept used in BGP discussions. BGP uses AS concepts to reason about routing between separate administrative networks.

This is one of the first BGP ideas learners need to understand.

Answer

A single switch VLAN

Answer

A specific OSPF area inside one router

Answer

A type of wireless access point

Question 12

R1 and R2 are connected via Ethernet and are configured with OSPF, but they fail to form an adjacency. Upon checking the interface configurations, you see that R1’s interface is in OSPF area 0 while R2’s interface is in area 1, and both interfaces use default timers and are in the same subnet. What is the most likely reason?

Accepted Answer

The OSPF areas do not match on the shared segment.. The most likely cause is an OSPF area mismatch on the shared segment. R1 and R2 are in the same IP subnet and use default hello/dead timers, so neither subnet mismatch nor timer mismatch is the problem. OSPF can run on Ethernet interfaces. However, OSPF requires neighbors on the same link to agree on the area ID; here they differ, preventing adjacency. Option B is incorrect because OSPF process IDs are locally significant and do not need to match.

Answer

The routers must use the same process ID.

Answer

The interfaces are in different IPv4 subnets.

Answer

OSPF cannot run on Ethernet interfaces.

Question 13

A network engineer receives a call that users in VLAN 10 on Switch B cannot ping the default gateway, which is a router on a stick connected to Switch A. The engineer checks the Spanning Tree Protocol state on the interface connecting Switch A to Switch B (GigabitEthernet0/1) and finds it is in a root-inconsistent state. Which command output best explains the cause of the issue?

Accepted Answer

Root guard is enabled and the port received a superior BPDU, causing it to become root-inconsistent.. Root guard, when enabled on a port, places that port into a root-inconsistent blocking state if it receives a superior BPDU, preventing the switch from becoming the root bridge. This root-inconsistent state stops forwarding traffic, which explains why users in VLAN 10 cannot reach the default gateway. The port remains physically up but is blocked by spanning tree, so normal interface status would not show a down state, making the root-inconsistent state the key indicator.

Answer

The interface is in err-disable state due to BPDU guard.

Answer

Loop guard is enabled and the port is in a blocking state due to missing BPDUs.

Answer

The port is in a forwarding state but the VLAN is misconfigured.

Question 14

An automation script must retrieve the current configuration state of a device from a REST API without modifying anything. Which HTTP method should it use?

Accepted Answer

GET. When a script only needs to read information, the normal REST choice is GET. In plain terms, GET asks the server, “Show me the current data,” without telling it to create, replace, or delete anything. That is why GET is the standard method for retrieving device state, configuration details, statistics, or inventory information from an API endpoint.

The other methods imply change. POST commonly creates or submits data. PUT commonly updates an existing resource. DELETE removes something. For a read-only query, GET is the clean and expected method.

Answer

DELETE

Answer

PUT

Answer

POST

Question 15

Match each basic automation term to its most accurate meaning.

Accepted Answer

Automation: Use of technology to perform tasks with minimal human intervention. Automation refers to the use of technology to perform tasks with minimal human intervention, reducing manual effort and errors. Orchestration is the coordination of multiple automated tasks into a seamless workflow, ensuring proper sequencing and dependencies. A script is a set of instructions written in a scripting language that is executed by an interpreter, often used to automate repetitive tasks. A workflow is a defined sequence of steps that accomplishes a specific business process, which can be automated to streamline operations.