CCNA Practice Test 50 — 15 Questions

Question 1

Drag and drop the following OSPFv2 neighbor state transitions and DR/BDR election steps into the correct order for a multi-access network with default priority values.

Accepted Answer

Down, Init, 2-Way (DR/BDR election), ExStart, Exchange, Loading, Full. The correct OSPF neighbor state progression on a multi-access network is: Down, Init, 2-Way (with DR/BDR election), ExStart (master/slave negotiation), Exchange (DBD exchange), Loading (link-state request and update), and Full. Each option missing the Loading state or placing it incorrectly fails to represent the complete adjacency process.

Answer

Down, Init, ExStart, Exchange, Loading, 2-Way (DR/BDR election), Full

Answer

Down, Init, 2-Way (DR/BDR election), Loading, Exchange, ExStart, Full

Answer

Down, Init, 2-Way (DR/BDR election), ExStart, Exchange, Full

Question 2

Match each route source or route type to its most accurate description.

Accepted Answer

Connected route: A route automatically added when an interface is configured with an IP address and is up.. Connected routes are automatically installed when an interface is configured with an IP address and is in the up/up state. Static routes are manually configured by an administrator to specify a fixed path. OSPF is a link-state routing protocol that uses cost as its metric and maintains a complete topology database. EIGRP is a hybrid protocol that uses bandwidth and delay as metrics and supports unequal-cost load balancing.

Question 3

Drag and drop the following steps into the correct order to configure AAA with a RADIUS server and 802.1X port authentication on a Cisco IOS-XE switch.

Accepted Answer

Enter global configuration mode and enable AAA globally using the 'aaa new-model' command.. Start by entering global configuration mode and enabling AAA with 'aaa new-model'. Next, create an authentication method list using 'aaa authentication dot1x default group radius' to define the method for 802.1X. Then, configure the RADIUS server parameters using 'radius-server host' and 'radius-server key' so the switch knows where to send authentication requests; note that the method list can reference the 'radius' group even before the server is specified. Finally, enable 802.1X system-wide with the global command 'dot1x system-auth-control' to activate 802.1X globally. This order ensures each prerequisite is met before the next step.

Question 4

A network engineer configures a primary default route via Gi0/0 (next-hop 192.168.12.2) and a floating static default route via Gi0/1 (next-hop 192.168.12.6) with AD 200. To test failover, the engineer issues the shutdown command on Gi0/0. After this, the router does not have a default route in the routing table. Which problem explains this behavior?

Accepted Answer

The backup interface Gi0/1 is administratively down, making the next-hop unreachable.. A floating static route is installed only if its next-hop is reachable and the primary route (with lower AD) is absent. Shutting down Gi0/0 removes the primary route. However, backup interface Gi0/1 is also administratively down, so the next-hop 192.168.12.6 is unreachable, and the floating route is not installed. Option A correctly identifies the interface status as the root cause. Option B is wrong because a higher AD (200) correctly designates this as a backup; a lower AD would make it primary. Option C is false; shutting down an interface removes connected routes, which causes the recursive static route to be purged. Option D is incorrect because floating static routes do not require a track object—the AD difference alone dictates failover when the primary is removed.

Answer

The floating static route uses an administrative distance of 200, which is too low to replace the primary route.

Answer

The primary default route remains in the routing table because shutting down Gi0/0 does not remove the static route.

Answer

The floating static route is missing a track object, so the router cannot detect the primary path failure.

Question 5

Drag and drop the following steps into the correct order to sequence the TCP three-way handshake between a client and a server.

Accepted Answer

Client sends SYN. The TCP three-way handshake starts with the client sending a SYN, followed by the server responding with SYN-ACK, and finally the client sending an ACK to establish the connection.

Answer

Server sends ACK

Question 6

Drag and drop the following steps into the correct order to describe the general workflow for AI-assisted network configuration automation: receive intent, decompose into sub-tasks, call tools, validate output, and apply closed-loop remediation.

Accepted Answer

receive intent, decompose into sub-tasks, call tools, validate output, apply closed-loop remediation [CORRECT]. The correct sequence for AI-assisted network configuration automation is: receive intent, decompose into sub-tasks, call tools, validate output, and apply closed-loop remediation. Only Option A follows this exact order. Options B, C, and D deviate from the standard workflow and are therefore incorrect.

Answer

call tools, receive intent, decompose into sub-tasks, validate output, apply closed-loop remediation

Answer

receive intent, call tools, decompose into sub-tasks, validate output, apply closed-loop remediation

Answer

receive intent, decompose into sub-tasks, validate output, call tools, apply closed-loop remediation

Question 7

Which two statements accurately describe WPA2 and WPA3 in wireless security?

Accepted Answer

Both are wireless security standards used to help protect WLAN access and traffic.. WPA2 and WPA3 are wireless security standards used to protect WLAN access and traffic. In practical terms, both are associated with securing wireless communication, but WPA3 is generally positioned as the newer standard with security improvements over WPA2. The key idea at CCNA level is recognizing them as WLAN security standards rather than confusing them with SSIDs, controllers, or radio bands.

You do not need deep protocol internals here. You need the role and relative positioning right.

Answer

Both are names for specific 802.11 radio frequencies.

Answer

WPA2 and WPA3 are types of trunk ports.

Answer

WPA3 eliminates the need for SSIDs.

Question 8

Drag and drop the VLAN/trunking commands and terms on the left to their correct descriptions or functions on the right.

Accepted Answer

switchport mode trunk: Configures an interface to carry multiple VLANs.. These pairings match common VLAN/trunking commands and terms to their correct descriptions.

Question 9

Drag and drop the following steps into the correct order to configure and recover from a BPDU Guard violation on a PortFast-enabled access port using Cisco IOS-XE CLI commands.

Accepted Answer

1. Enter global configuration mode. 2. Configure spanning-tree portfast default. 3. Enter interface configuration mode. 4. Configure spanning-tree bpduguard enable. 5. Exit to privileged EXEC mode. 6. Verify errdisable state. 7. Enter interface configuration mode. 8. Issue shutdown command. 9. Issue no shutdown command.. Only Option A correctly lists the steps to configure and manually recover from a BPDU Guard violation on a PortFast-enabled port. Option B is invalid because the command 'clear spanning-tree bpduguard' does not exist; the proper recovery is shutdown/no shutdown. Option C incorrectly applies the global command 'spanning-tree portfast bpduguard default' in interface mode; it should be used in global configuration mode. Option D includes an unnecessary 'Enter interface configuration mode' step after the global recovery command and does not reflect the correct sequence for automatic recovery.

Answer

1. Enter global configuration mode. 2. Configure spanning-tree portfast default. 3. Enter interface configuration mode. 4. Configure spanning-tree bpduguard enable. 5. Exit to privileged EXEC mode. 6. Issue clear spanning-tree bpduguard command. 7. Verify port is up.

Answer

1. Enter global configuration mode. 2. Configure spanning-tree portfast default. 3. Enter interface configuration mode. 4. Configure spanning-tree portfast bpduguard default. 5. Exit to privileged EXEC mode. 6. Verify errdisable state. 7. Enter interface configuration mode. 8. Issue shutdown command. 9. Issue no shutdown command.

Answer

1. Enter global configuration mode. 2. Configure spanning-tree portfast default. 3. Enter interface configuration mode. 4. Configure spanning-tree bpduguard enable. 5. Exit to privileged EXEC mode. 6. Issue errdisable recovery cause bpduguard command. 7. Wait for timer. 8. Verify port is up.

Question 10

Drag and drop the following steps into the correct order to describe the TCP three-way handshake process between a client and a server.

Accepted Answer

Client sends SYN (seq=x). The TCP three-way handshake begins with the client sending a SYN (A) to initiate the connection. The server replies with a SYN-ACK (B) to acknowledge the client's SYN and provide its own sequence number. Finally, the client sends an ACK (C) to confirm the server's SYN, completing the handshake. Option D, "Server sends ACK (ack=x+1)," is not part of the three-way handshake; an ACK from the server would be redundant at this stage and actually occurs during the four-way connection termination, not establishment.

Answer

Server sends ACK (ack=x+1)

Question 11

Drag and drop the following steps into the correct order to troubleshoot an end-to-end connectivity issue using a bottom-up approach.

Accepted Answer

Check physical layer connectivity and interface status. The correct troubleshooting order follows the OSI model bottom-up: start with physical connectivity (A), then verify Layer 3 addressing (B), use diagnostic tools (C) to isolate the failure, and finally implement the solution and verify restoration (D). Skipping layers can lead to misdiagnosis.

Question 12

Drag and drop the switch port configuration commands on the left to the correct descriptions on the right.

Accepted Answer

switchport mode access: Statically sets the port as an access port.. The command 'switchport mode access' statically sets the port as an access port. 'switchport access vlan 10' assigns VLAN 10 as the data VLAN for connected devices. 'switchport voice vlan 20' defines the VLAN used by a Cisco IP phone for voice traffic. 'switchport mode trunk' forces the port into permanent trunking mode. 'switchport trunk allowed vlan 100,200' restricts the trunk to carry only VLANs 100 and 200.

Answer

switchport mode trunk: Restricts the trunk to carry only VLANs 100 and 200.

Answer

switchport trunk allowed vlan 100,200: Forces the port into permanent trunking mode.

Question 13

A network administrator is troubleshooting connectivity between two directly connected Cisco switches. Hosts on VLAN 10 connected to Switch A cannot ping the default gateway on Switch B. The interface on Switch A shows 'up/up' but there are excessive CRC errors and runts. The administrator checks the interface configuration on both switches. What is the most likely cause of the issue?

Accepted Answer

Mismatched duplex and speed settings between the interfaces.. The presence of excessive CRC errors and runts on an interface that is 'up/up' strongly indicates a Layer 1 or Layer 2 duplex mismatch. When one switch is set to full-duplex and the other to half-duplex (or auto-negotiation fails), the half-duplex side will detect collisions and retransmit, while the full-duplex side will not, leading to frame corruption (CRC errors) and truncated frames (runts). Configuring both interfaces with the same duplex and speed settings (e.g., full-duplex and 1000 Mbps) resolves this mismatch, restoring proper connectivity for VLAN 10 traffic to the default gateway.

Answer

Replace the faulty Ethernet cable.

Answer

Disable spanning tree on both interfaces to prevent loop prevention from blocking traffic.

Answer

Assign the interfaces to the same VLAN to ensure Layer 2 connectivity.

Question 14

A network technician is troubleshooting a connectivity issue between two directly connected switches, SW1 and SW2. Hosts on VLAN 10 connected to SW1 can ping each other but cannot ping the default gateway or any host on VLAN 10 connected to SW2. The interface on SW1 is up/up, but the interface on SW2 is up/down. What is the most likely cause of the problem?

Accepted Answer

Ensure both switches are configured for the same duplex setting, preferably by enabling autonegotiation on both interfaces.. The interface on SW2 is up/down, which typically indicates a Layer 1 issue such as a duplex mismatch. Duplex mismatch occurs when one switch is manually set to full duplex and the other to half duplex or auto-negotiation fails, causing the side expecting full duplex to report up/down due to excessive errors. Option A is incorrect because MTU mismatch would cause connectivity issues but not an up/down interface state. Option C is incorrect because a faulty cable would likely cause both interfaces to be down/down, not up/down. Option D is incorrect because late collisions are a symptom of duplex mismatch, not a separate cause; increasing collision window size is not a standard troubleshooting step. The correct solution is to ensure both switches use the same duplex setting, preferably via autonegotiation (IEEE 802.3u).

Answer

Configure the interface on SW2 to use a different MTU value.

Answer

Replace the Ethernet cable connecting SW1 and SW2.

Answer

Check for late collisions on the interface and increase the collision window size.

Question 15

A network engineer is troubleshooting a link between two Cisco Catalyst 9300 switches that are connected via a 10GBASE-SR SFP+ module on each end over OM3 multimode fiber. The link is up, but the interface counters show a high number of CRC errors and runts. The engineer runs 'show interfaces Gi1/0/1' and 'show interfaces Gi1/0/1 transceiver details'. What is the most likely cause of the errors?

Accepted Answer

The receive optical power is too low, indicating a fiber or connector issue.. The high CRC errors and runts on a 10GBASE-SR link over OM3 fiber, combined with the 'show interfaces transceiver details' command, point to a physical-layer issue. Low receive optical power (below the receiver sensitivity threshold) causes bit errors that manifest as CRC errors and runts, even though the link is up. This is the most common cause when the fiber and transceivers are otherwise compatible.

Answer

The SFP+ module is faulty and needs replacement.

Answer

The fiber patch cables are too long, exceeding the 300-meter distance limit for 10GBASE-SR over OM3 fiber.

Answer

The interface speed is mismatched; the switch interface shows 1000Mb/s but the SFP+ is 10GBASE-SR.