The answer is PortFast with BPDU Guard. PortFast immediately transitions the port to the forwarding state upon link-up, bypassing STP listening and learning phases, which explains the instant connectivity. BPDU Guard then monitors for incoming BPDUs on that port; when one is received—indicating an unauthorized switch or misconfiguration on what should be an edge port—the port is placed into err-disabled state. On the CCNA 200-301 v2 exam, this scenario tests your understanding of STP edge-port hardening and the distinct roles of each feature: PortFast for faster convergence, BPDU Guard for security. A common trap is confusing BPDU Guard with BPDU Filter, which silently drops BPDUs without disabling the port. Remember the mnemonic: PortFast gets you fast, BPDU Guard locks it down fast.
CCNA Switching and Network Access Practice Question
This 200-301 practice question tests your understanding of switching and network access. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. A key principle to apply: portFast immediately transitions a switch port to forwarding state to speed up host connectivity by skipping STP listening and learning states.. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A switch port connected to an edge host immediately transitions to forwarding and then later goes err-disabled after a BPDU is received. Which feature combination most likely produced this behavior?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Clue: "immediately / without restart"
Why it matters: Time or reboot constraint — the correct answer must take effect right away without requiring a reboot or reload.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
PortFast with BPDU Guard
The most likely combination is PortFast with BPDU Guard. In practical terms, PortFast explains why the port moved quickly into forwarding when the host connected. BPDU Guard explains why the same port later shut down after seeing a BPDU that should not normally appear on an edge port.
This is a very common enterprise edge-port design pattern and a classic exam scenario.
Key principle: PortFast immediately transitions a switch port to forwarding state to speed up host connectivity by skipping STP listening and learning states.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
PortFast with BPDU Guard
Why this is correct
This is correct because PortFast speeds forwarding and BPDU Guard disables the edge port if a BPDU appears.
Clue confirmation
The clue words "most likely", "immediately / without restart" in the question point toward this answer.
Related concept
PortFast immediately transitions a switch port to forwarding state to speed up host connectivity by skipping STP listening and learning states.
✗
NetFlow with SNMP traps
Why it's wrong here
This is wrong because those are visibility technologies, not STP edge-port controls.
When this WOULD be correct
If the exam question asked about monitoring and alerting mechanisms for network traffic and events, a scenario involving the use of NetFlow to collect data and SNMP traps to notify administrators of significant events would make this option correct.
✗
OSPF passive-interface with EUI-64
Why it's wrong here
This is wrong because those features are unrelated to switchport STP behavior.
When this WOULD be correct
If the question were about configuring OSPF on a router where the administrator wants to prevent OSPF advertisements on specific interfaces while using EUI-64 addressing for IPv6, this option would be correct. It would focus on controlling OSPF traffic without affecting Layer 2 switch behavior.
✗
WPA3 with CAPWAP
Why it's wrong here
This is wrong because those are wireless concepts, not wired edge-port protections.
When this WOULD be correct
If the exam question asked about wireless network security configurations and their impact on access point behavior in a CAPWAP environment, then WPA3 could be the correct answer, particularly in scenarios involving secure connections and management of wireless clients.
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.
✓PortFast with BPDU GuardCorrect answer▾
Why this is correct
This is correct because PortFast speeds forwarding and BPDU Guard disables the edge port if a BPDU appears.
✗NetFlow with SNMP trapsWrong answer — click to see why▾
Why this is wrong here
NetFlow is used for traffic monitoring and analysis, while SNMP traps are used for network management notifications. Neither feature affects STP behavior or port state transitions; they do not cause a port to go err-disabled upon receiving a BPDU.
★ When this WOULD be the correct answer
If the exam question asked about monitoring and alerting mechanisms for network traffic and events, a scenario involving the use of NetFlow to collect data and SNMP traps to notify administrators of significant events would make this option correct.
Why candidates choose this
Students might confuse the concept of 'traps' or 'alerts' with the err-disabled state, thinking that SNMP traps could trigger a port shutdown. However, err-disabled is a hardware-level protection mechanism, not a management action.
✗OSPF passive-interface with EUI-64Wrong answer — click to see why▾
Why this is wrong here
OSPF passive-interface prevents OSPF from sending routing updates on an interface but does not affect STP or port security. EUI-64 is used for IPv6 address generation. Neither feature relates to BPDU handling or err-disable behavior.
★ When this WOULD be the correct answer
If the question were about configuring OSPF on a router where the administrator wants to prevent OSPF advertisements on specific interfaces while using EUI-64 addressing for IPv6, this option would be correct. It would focus on controlling OSPF traffic without affecting Layer 2 switch behavior.
Why candidates choose this
The term 'passive' might be misassociated with a port being disabled or inactive. Additionally, EUI-64 might be confused with a security feature, but it is unrelated to STP.
✗WPA3 with CAPWAPWrong answer — click to see why▾
Why this is wrong here
WPA3 is a wireless security protocol, and CAPWAP is a control and provisioning protocol for wireless access points. These are entirely unrelated to wired switch port STP behavior and cannot cause a port to go err-disabled due to BPDU reception.
★ When this WOULD be the correct answer
If the exam question asked about wireless network security configurations and their impact on access point behavior in a CAPWAP environment, then WPA3 could be the correct answer, particularly in scenarios involving secure connections and management of wireless clients.
Why candidates choose this
The acronyms might be confusing; a student might think 'BPDU' is related to wireless or that 'Guard' is similar to security protocols. However, BPDU Guard is a wired STP feature.
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?”
Common exam traps
Common exam trap: answer the scenario, not the keyword
Beware of confusing BPDU Guard with other protection mechanisms like Root Guard or Loop Guard; each serves a different purpose.
Detailed technical explanation
How to think about this question
PortFast is a Cisco Catalyst switch feature that immediately transitions a switch port into the forwarding state, bypassing the usual Spanning Tree Protocol (STP) listening and learning states. This behavior is designed for ports connected directly to end devices, such as workstations or servers, to reduce the delay in network connectivity during link initialization.
BPDU Guard is a complementary STP feature that disables a PortFast-enabled port if it receives a Bridge Protocol Data Unit (BPDU). Since edge ports should not receive BPDUs, the presence of a BPDU indicates a potential network topology change or misconfiguration. BPDU Guard places the port into an err-disabled state to prevent possible loops or STP disruptions.
The combination of PortFast and BPDU Guard is a common enterprise best practice to protect the network edge. PortFast accelerates host connectivity, while BPDU Guard prevents accidental or malicious introduction of switches or bridges on edge ports. The exam trap is confusing PortFast with other unrelated features or misunderstanding BPDU Guard’s role, which can lead to incorrect answers about STP behavior and edge port security.
KKey Concepts to Remember
PortFast immediately transitions a switch port to forwarding state to speed up host connectivity by skipping STP listening and learning states.
BPDU Guard disables a PortFast-enabled port by placing it in err-disabled state if any BPDU is received on that port.
Edge ports configured with PortFast should never receive BPDUs under normal network operation.
Receiving a BPDU on a PortFast-enabled port triggers BPDU Guard to protect the network from potential loops or misconfigurations.
BPDU Guard helps maintain network stability by preventing unauthorized switches from connecting to edge ports.
PortFast and BPDU Guard together form a security mechanism that balances fast host access with loop prevention.
Switch ports connected to other switches should not use PortFast because they need to participate fully in STP.
Err-disabled state caused by BPDU Guard requires manual or automatic recovery to restore port functionality.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
PortFast immediately transitions a switch port to forwarding state to speed up host connectivity by skipping STP listening and learning states.
Real-world example
How this comes up in practice
A network engineer at a university connects two campus buildings via a fibre link. Both routers run OSPF, but no adjacency forms — even though both routers can ping each other. The engineer finds one router is in area 0 and the other in area 1. OSPF adjacency requires matching area numbers, hello/dead timers, and network type. IP reachability alone is not enough.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 200-301 question in full detail.
Review portFast immediately transitions a switch port to forwarding state to speed up host connectivity by skipping STP listening and learning states., then practise related 200-301 questions on the same topic to reinforce the concept.
Switching and Network Access — This question tests Switching and Network Access — PortFast immediately transitions a switch port to forwarding state to speed up host connectivity by skipping STP listening and learning states..
What is the correct answer to this question?
The correct answer is: PortFast with BPDU Guard — The most likely combination is PortFast with BPDU Guard. In practical terms, PortFast explains why the port moved quickly into forwarding when the host connected. BPDU Guard explains why the same port later shut down after seeing a BPDU that should not normally appear on an edge port.
This is a very common enterprise edge-port design pattern and a classic exam scenario.
What should I do if I get this 200-301 question wrong?
Review portFast immediately transitions a switch port to forwarding state to speed up host connectivity by skipping STP listening and learning states., then practise related 200-301 questions on the same topic to reinforce the concept.
Are there clue words in this question I should notice?
Yes — watch for: "most likely", "immediately / without restart". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
PortFast immediately transitions a switch port to forwarding state to speed up host connectivity by skipping STP listening and learning states.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Why is PortFast typically enabled on switch ports connected to end devices?
medium
✓ A.To let end-device ports reach forwarding state more quickly
B.To make access ports participate in OSPF
C.To convert all access ports into trunks
D.To disable Ethernet addressing on PCs
Why A: PortFast is enabled so access ports connected to end devices can move to forwarding more quickly instead of waiting through the normal spanning-tree listening and learning transitions. In plain language, it helps a user’s PC, printer, or similar endpoint start communicating sooner after the link comes up. That can reduce delays at startup and prevent certain device timeout problems.
PortFast is not intended as a loop-prevention mechanism by itself, and it should not normally be used carelessly on links to other switches. That is why it is commonly paired with BPDU Guard on edge ports. The correct answer is the one focused on faster transition for end-device access links rather than on unrelated routing or VLAN functions.
Last reviewed: May 17, 2026
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.