CCNA Switching and Network Access Practice Test 20 — 15 Questions

Question 1

Which of the following sequences correctly configures and verifies PortFast and BPDU Guard on a Cisco IOS-XE switch interface, and then recovers after a BPDU guard violation?

Accepted Answer

Enter global configuration mode, then interface configuration mode, enable PortFast, enable BPDU Guard, verify with show commands, and recover by shutting down and no shutting down the interface.. The correct sequence is described in option A: enter global configuration mode, then interface configuration mode, enable PortFast first, then BPDU Guard, verify with show commands, and recover by shutting down and no shutting down the interface. Options B, C, and D are incorrect because they contain errors such as wrong order of enabling features, improper recovery methods (reload, removal of BPDU Guard, or clear errdisable interface), or enabling BPDU Guard globally. Only option A follows the proper Cisco IOS-XE procedure for configuring and recovering from a BPDU guard violation.

Answer

Enter interface configuration mode, enable BPDU Guard, enable PortFast, exit to global config, verify, and recover by reloading the switch.

Answer

Enter global configuration mode, enable BPDU Guard globally, then enter interface configuration mode, enable PortFast, verify, and recover by removing BPDU Guard.

Answer

Enter interface configuration mode, enable PortFast, enable BPDU Guard, exit to global config, verify, and recover by issuing 'clear errdisable interface' command.

Question 2

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 in RSTP.

Accepted Answer

Configure PortFast and BPDU guard on the interface.. Configure PortFast and BPDU guard on the access port. Then trigger a violation by connecting an unauthorized switch, which causes the port to error-disable. Diagnose by checking the error-disabled status. To recover, first remove the offending device, then cycle the port with shutdown and no shutdown; otherwise the port will immediately go error-disabled again.

Question 3

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.

Accepted Answer

Configure PortFast and BPDU guard on the interface.. The correct order is: first configure PortFast and BPDU guard on the interface (A). Then connect a switch to trigger a BPDU guard violation (B). Next, perform a shutdown followed by no shutdown to recover from the errdisable state (C). Finally, verify that the port is forwarding traffic (D). This sequence ensures the violation occurs before recovery, which is the realistic scenario.

Question 4

Drag and drop the following steps into the correct order to configure PortFast and BPDU Guard on a switch access port, and then recover after a BPDU Guard error-disable event.

Accepted Answer

Enter global configuration mode, then interface configuration mode, enable PortFast, enable BPDU Guard, and after an error-disable event, manually re-enable the interface using the 'shutdown' command followed by the 'no shutdown' command.. This drag-and-drop question presents four distinct step sequences, each representing a valid method to configure PortFast and BPDU Guard on an access port and handle a BPDU Guard error-disable event. Option A describes the manual recovery method: enter global config, interface config, enable PortFast, enable BPDU Guard, then manually recover with 'shutdown' followed by 'no shutdown'. Option B describes automatic recovery using the 'errdisable recovery cause bpduguard' global command, which must be configured before the error occurs. Option C describes an alternative using the 'clear spanning-tree bpduguard' command to recover without manual interface reset. Option D uses the global default 'spanning-tree portfast bpduguard default' command. All sequences are correct when ordered properly for their specific approach.

Question 5

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 6

Which TWO statements correctly describe the behavior of PortFast and BPDU Guard on a Cisco switch?

Accepted Answer

PortFast immediately transitions a port from blocking to forwarding state, bypassing listening and learning.. PortFast immediately transitions an access port from blocking to forwarding, bypassing listening and learning (Option A). BPDU Guard errdisables a PortFast-enabled port if any BPDU is received, protecting against accidental loops (Option B). Option C is incorrect because PortFast does not alter BPDU handling; the port still processes BPDUs and reverts to normal STP if one is received. Option D is false because BPDU Guard disables the port entirely rather than ignoring BPDUs. Option E is incorrect because BPDU Guard is typically configured on access ports connected to end devices, not on trunk ports.

Answer

PortFast allows BPDUs to pass through the port normally, but the port remains in forwarding state.

Answer

BPDU Guard prevents the port from becoming a root port or designated port by ignoring superior BPDUs.

Answer

BPDU Guard is typically configured on trunk ports to prevent loops between switches.

Question 7

Drag and drop the following steps into the correct order to capture and analyze traffic on IOS-XE using the embedded packet capture feature, then export the capture for analysis in Wireshark to isolate a Layer 2 or Layer 3 fault.

Accepted Answer

Define the capture point specifying the interface and direction (monitor capture point command). First, define the capture point. Then start the capture. After capturing sufficient data, stop the capture to release resources. Finally, export the capture to a TFTP server for analysis.

Question 8

A network troubleshooter is using Cisco IOS-XE's embedded packet capture feature to capture traffic on an interface and then analyze it in Wireshark to isolate a Layer 2 or Layer 3 fault. Which of the following sequences represents the correct order of steps?

Accepted Answer

Define the capture point with interface and optional filter, start the capture, stop the capture, export the capture file, then analyze in Wireshark.. The correct workflow is to first define the capture point (interface and any filters), then start the capture, stop it when sufficient data is collected, export the captured packets to a file, and finally open that file in Wireshark for analysis. Starting the capture before defining the point, exporting before stopping, or defining the point after stopping all result in an invalid or incomplete capture process.

Answer

Start the capture, define the capture point with interface and filter, stop the capture, export the capture file, then analyze in Wireshark.

Answer

Define the capture point, start the capture, export the capture file, stop the capture, then analyze in Wireshark.

Answer

Start the capture, stop the capture, define the capture point, export the capture file, then analyze in Wireshark.

Question 9

Drag and drop the following steps into the correct order to capture and analyze traffic on IOS-XE using the embedded packet capture feature, and in Wireshark to isolate a Layer 2 or Layer 3 fault.

Accepted Answer

Access privileged EXEC mode, create a capture buffer, associate a capture point, start the capture, stop and export the capture, analyze in Wireshark. For IOS‑XE embedded packet capture, the correct order is: 1) Access privileged EXEC mode (required for all monitor commands), 2) Create a capture buffer, 3) Associate a capture point, 4) Start the capture, 5) Stop the capture, 6) Export the capture, 7) Analyze in Wireshark. Options B, C, and D each violate the required sequence: B starts buffer creation before entering privileged mode, C associates the point before creating the buffer, and D omits the critical 'start' step entirely.

Answer

Create a capture buffer, access privileged EXEC mode, associate a capture point, start the capture, stop and export the capture, analyze in Wireshark

Answer

Access privileged EXEC mode, associate a capture point, create a capture buffer, start the capture, stop and export the capture, analyze in Wireshark

Answer

Access privileged EXEC mode, create a capture buffer, associate a capture point, stop and export the capture, analyze in Wireshark

Question 10

Drag and drop the following steps into the correct order to capture and analyze traffic on IOS-XE using the embedded packet capture feature, then export to Wireshark to isolate a Layer 2 or Layer 3 fault.

Accepted Answer

Enter privileged EXEC mode, define the capture buffer, specify the interface and direction, start the capture, stop the capture, export the capture to a .pcap file, transfer the file, and analyze in Wireshark.. First enter privileged mode, then define the capture buffer, specify the interface and direction, start the capture, stop it after collecting data, export to a .pcap file, then transfer and analyze in Wireshark.

Answer

Enter global configuration mode, define the capture buffer, specify the interface and direction, start the capture, stop the capture, export the capture to a .pcap file, transfer the file, and analyze in Wireshark.

Answer

Enter privileged EXEC mode, specify the interface and direction, define the capture buffer, start the capture, stop the capture, export the capture to a .pcap file, transfer the file, and analyze in Wireshark.

Answer

Enter privileged EXEC mode, define the capture buffer, specify the interface and direction, start the capture, export the capture to a .pcap file, stop the capture, transfer the file, and analyze in Wireshark.

Question 11

What is the correct order of steps to capture and analyze traffic on IOS-XE using the embedded packet capture feature, and in Wireshark to isolate a Layer 2 or Layer 3 fault?

Accepted Answer

Define the capture point with interface and optional filter, then start the capture, stop it, and export the capture file for analysis in Wireshark.. The correct order for embedded packet capture on IOS-XE is to first define the capture point with the desired interface and optional filter, then start the capture, stop it after capturing the needed traffic, and finally export the file for analysis in Wireshark. Option A accurately reflects this sequence. Option B fails because the capture must be defined before starting. Option C fails because exporting should occur after stopping the capture. Option D fails because analysis is performed externally, not on the router.

Answer

Start the capture immediately, then define the capture point with interface and filter, stop the capture, and export the file for analysis.

Answer

Define the capture point, start the capture, export the file, and then stop the capture.

Answer

Define the capture point, start the capture, stop it, then analyze the capture directly on the router without exporting.

Question 12

Which TWO statements accurately describe the use of packet capture tools for troubleshooting Layer 2/3 issues?

Accepted Answer

A packet capture that shows frames with the same source and destination MAC addresses but different 802.1Q VLAN tags indicates a possible trunk misconfiguration.. Frames with identical source and destination MAC addresses but different 802.1Q VLAN tags indicate the same device is reachable on multiple VLANs, which commonly results from a misconfigured trunk (e.g., native VLAN mismatch or inconsistent allowed VLAN lists). Option D is correct because seeing ICMP echo requests leave a router but no echo replies return suggests the reply is blocked or dropped at some intermediate Layer 3 hop, pointing to a routing problem rather than a Layer 2 issue. Option A is wrong: ARP requests without replies point to a Layer 2 problem (e.g., unreachable destination or filtering), not a Layer 3 routing issue. Option C is wrong: ICMP echo requests without replies could have many causes (ACLs, firewalls, routing) – a switching loop would typically generate excessive broadcasts, not just missing replies. Option E is wrong: TCP SYN without SYN-ACK typically indicates a Layer 4 filtering or unreachable server issue, or possibly a Layer 3 routing problem, not a pure Layer 1 physical fault.

Answer

A packet capture that shows ARP requests with no ARP replies indicates a Layer 3 routing issue.

Answer

A packet capture that shows ICMP echo requests but no echo replies confirms a Layer 2 switching loop.

Answer

A packet capture that shows TCP SYN packets with no SYN-ACK replies indicates a Layer 1 physical issue.

Question 13

Drag and drop the following steps into the correct order to configure Root Guard on designated ports, Loop Guard on non-designated ports, and BPDU Guard on PortFast ports, and to recover a port that enters err-disabled due to a BPDU guard violation.

Accepted Answer

1. Configure Root Guard on designated ports. 2. Configure Loop Guard on non-designated ports. 3. Configure BPDU Guard on PortFast ports. 4. To recover a port that enters err-disabled due to BPDU Guard violation, manually shut and no shut the interface.. Root Guard on designated, Loop Guard on non-designated, then BPDU Guard on PortFast; recovery requires interface reset after violation.

Answer

1. Configure BPDU Guard on PortFast ports. 2. Configure Loop Guard on non-designated ports. 3. Configure Root Guard on designated ports. 4. To recover a port that enters err-disabled due to BPDU Guard violation, re-enable BPDU Guard on the port.

Answer

1. Configure Loop Guard on non-designated ports. 2. Configure Root Guard on designated ports. 3. Configure BPDU Guard on PortFast ports. 4. To recover a port that enters err-disabled due to BPDU Guard violation, configure errdisable recovery cause bpduguard.

Answer

1. Configure Root Guard on designated ports. 2. Configure BPDU Guard on PortFast ports. 3. Configure Loop Guard on non-designated ports. 4. To recover a port that enters err-disabled due to BPDU Guard violation, remove BPDU Guard from the port.

Question 14

Drag and drop the following steps into the correct order to configure Root Guard on designated ports, Loop Guard on non-designated ports, and BPDU Guard on PortFast ports, and then recover a port that enters err-disabled state.

Accepted Answer

1. Configure Root Guard on designated ports. 2. Configure Loop Guard on non-designated ports. 3. Configure BPDU Guard on PortFast ports. 4. Enable errdisable recovery globally. 5. Re-enable the err-disabled port manually.. Only option A correctly follows the sequence of configuring Root Guard on designated ports, Loop Guard on non-designated ports, BPDU Guard on PortFast ports, then enabling errdisable recovery globally, and finally manually re-enabling the port. Option B assigns Loop Guard to designated ports and Root Guard to non-designated ports, which is incorrect. Option C correctly assigns protections but starts with BPDU Guard, deviating from the specified order. Option D assigns Root Guard to non-designated ports and Loop Guard to designated ports, which is incorrect.

Answer

1. Configure Loop Guard on designated ports. 2. Configure Root Guard on non-designated ports. 3. Configure BPDU Guard on PortFast ports. 4. Re-enable the err-disabled port manually. 5. Enable errdisable recovery globally.

Answer

1. Configure BPDU Guard on PortFast ports. 2. Configure Root Guard on designated ports. 3. Configure Loop Guard on non-designated ports. 4. Re-enable the err-disabled port manually. 5. Enable errdisable recovery globally.

Answer

1. Configure Root Guard on non-designated ports. 2. Configure Loop Guard on designated ports. 3. Configure BPDU Guard on PortFast ports. 4. Enable errdisable recovery globally. 5. Re-enable the err-disabled port manually.

Question 15

Drag and drop the following steps into the correct order to configure Root Guard on a designated port, Loop Guard on a non-designated port, and BPDU Guard on a PortFast port, along with the recovery steps when a port enters err-disabled state.

Accepted Answer

1. Enter global configuration mode. 2. Configure Root Guard on the designated port. 3. Configure Loop Guard on the non-designated port. 4. Configure BPDU Guard on the PortFast-enabled port. 5. Configure errdisable recovery for BPDU Guard.. The order follows the logical sequence: enter config mode, then configure each guard feature on its respective port, and finally set the errdisable recovery to automatically re-enable ports after a BPDU Guard violation.

Answer

1. Enter global configuration mode. 2. Configure BPDU Guard on the PortFast-enabled port. 3. Configure Root Guard on the designated port. 4. Configure Loop Guard on the non-designated port. 5. Configure errdisable recovery for BPDU Guard.

Answer

1. Enter global configuration mode. 2. Configure Loop Guard on the non-designated port. 3. Configure Root Guard on the designated port. 4. Configure BPDU Guard on the PortFast-enabled port. 5. Configure errdisable recovery for BPDU Guard.

Answer

1. Enter global configuration mode. 2. Configure Root Guard on the designated port. 3. Configure BPDU Guard on the PortFast-enabled port. 4. Configure Loop Guard on the non-designated port. 5. Configure errdisable recovery for BPDU Guard.