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Switching and Network AccesshardTroubleshootingObjective-mapped

CCNA Switching and Network Access Practice Question

Exhibit

R1# show interfaces status
Port      Name   Status       Vlan    Duplex  Speed Type
Gi0/0            connected    routed    full   1000  SFP
Gi0/1            err-disabled 10       auto   auto  10/100/1000BaseTX
Gi0/2            notconnect   10       auto   auto  10/100/1000BaseTX
Gi0/3            connected    routed    full   1000  SFP

R1# show running-config | section interface GigabitEthernet0/1
interface GigabitEthernet0/1
 switchport mode access
 switchport access vlan 10
 spanning-tree bpduguard enable
 spanning-tree portfast

R1# show running-config | include errdisable

R1# show spanning-tree vlan 10
  VLAN0010
    Spanning tree enabled protocol rstp
    Root ID    Priority    24586
               Address     aaaa.bbbb.cccc
               This bridge is the root
    Bridge ID  Priority    24586  (priority 24576 sys-id-ext 10)
               Address     aaaa.bbbb.cccc
    Interface        Role Sts Cost      Prio.Nbr Type
    Gi0/1            Desg BKN*4         128.2    P2p *BPDU_Guard
    Gi0/2            Desg BLK 4         128.3    P2p

*BPDU_Guard: err-disabled

You are connected to R1, a multilayer switch acting as the root bridge for VLAN 10. The network has experienced a loop, and interface GigabitEthernet0/1 on R1 is currently in err-disabled state due to a BPDU guard violation. Configure the switch to recover automatically from err-disable state after 300 seconds, then verify that the interface comes back up.

⚠ Common exam trap

The trap is that candidates may confuse enabling BPDU guard with configuring recovery, or they may think recovery commands are applied per-interface. Remember that errdisable recovery is a global setting, and you must specify the exact cause unless you want to recover from all causes.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

Configure 'errdisable recovery cause bpduguard' and 'errdisable recovery interval 300' globally, then verify with 'show interfaces status'.

The interface Gi0/1 is in err-disabled state because BPDU Guard detected an unexpected BPDU on a PortFast-enabled access port. To recover automatically, configure errdisable recovery cause bpduguard and set the recovery interval to 300 seconds with errdisable recovery interval 300. After applying these commands, the interface will automatically come out of err-disable state after 300 seconds. The blocking port on Gi0/2 is expected because R1 is the root bridge and Gi0/2 is an alternate port providing redundancy; no action is needed for that blocking state.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Configure 'errdisable recovery cause bpduguard' and 'errdisable recovery interval 300' globally, then verify with 'show interfaces status'.

    Why this is correct

    This is correct because the errdisable recovery cause bpduguard command enables automatic recovery for interfaces disabled by BPDU guard, and the errdisable recovery interval 300 sets the recovery timer to 300 seconds. The 'show interfaces status' command verifies that the interface returns to up/up state.

  • Configure 'spanning-tree portfast bpduguard default' and 'errdisable recovery interval 300' globally, then verify with 'show spanning-tree'.

    Why it's wrong here

    This is incorrect because 'spanning-tree portfast bpduguard default' enables BPDU guard on all PortFast-enabled ports, but it does not enable automatic recovery from err-disable state. The 'show spanning-tree' command does not show errdisable recovery status.

  • Configure 'errdisable recovery cause all' and 'errdisable recovery interval 300' globally, then verify with 'show errdisable recovery'.

    Why it's wrong here

    This is incorrect because 'errdisable recovery cause all' enables recovery for all errdisable causes, which is overly broad and not recommended. The question specifically asks to recover from BPDU guard violation, so using 'cause bpduguard' is more precise. While 'show errdisable recovery' is a valid verification command, the configuration is not optimal.

  • Configure 'errdisable recovery cause bpduguard' and 'errdisable recovery interval 300' on interface GigabitEthernet0/1, then verify with 'show interfaces GigabitEthernet0/1'.

    Why it's wrong here

    This is incorrect because errdisable recovery commands are configured globally, not on a per-interface basis. Applying them under the interface will result in an error. The 'show interfaces' command can show the interface status, but the configuration is invalid.

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.

Configure 'errdisable recovery cause bpduguard' and 'errdisable recovery interval 300' globally, then verify with 'show interfaces status'.Correct answer

Why this is correct

This is correct because the errdisable recovery cause bpduguard command enables automatic recovery for interfaces disabled by BPDU guard, and the errdisable recovery interval 300 sets the recovery timer to 300 seconds. The 'show interfaces status' command verifies that the interface returns to up/up state.

Configure 'spanning-tree portfast bpduguard default' and 'errdisable recovery interval 300' globally, then verify with 'show spanning-tree'.Wrong answer — click to see why

Why this is wrong here

The specific factual error: 'spanning-tree portfast bpduguard default' enables BPDU guard, not recovery. Recovery requires 'errdisable recovery cause bpduguard'.

Why candidates choose this

Candidates pick this because they confuse enabling BPDU guard with configuring recovery, and they may think 'show spanning-tree' shows errdisable status.

Configure 'errdisable recovery cause all' and 'errdisable recovery interval 300' globally, then verify with 'show errdisable recovery'.Wrong answer — click to see why

Why this is wrong here

The specific factual error: Using 'cause all' is not the best practice; the question implies a specific cause. Also, the verification command is correct but the configuration is not precise.

Why candidates choose this

Candidates pick this because 'cause all' seems like a catch-all solution, and they may not realize that specific recovery is preferred.

Configure 'errdisable recovery cause bpduguard' and 'errdisable recovery interval 300' on interface GigabitEthernet0/1, then verify with 'show interfaces GigabitEthernet0/1'.Wrong answer — click to see why

Why this is wrong here

The specific factual error: errdisable recovery is a global configuration command, not interface-specific.

Why candidates choose this

Candidates pick this because they think recovery settings should be applied directly to the affected interface, similar to other interface-specific commands.

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?”

Visual reference

SW1 Root Bridge SW2 SW3 BLK DP DP RP RP STP blocks one link to prevent loops DP = Designated Port RP = Root Port BLK = Blocked

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JA

Written by Johnson Ajibi, MSc IT Security

Senior Network & Security Engineer · founder of Courseiva

This 200-301 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 200-301 exam.