- A
PortFast immediately transitions a port from blocking to forwarding state, bypassing listening and learning.
This is correct. PortFast allows a port to go directly to forwarding, reducing the time a host takes to start sending traffic.
- B
BPDU Guard disables a PortFast-enabled port if it receives any BPDU.
This is correct. BPDU Guard err-disables a PortFast port upon receiving a BPDU, protecting against accidental loops.
- C
PortFast allows BPDUs to pass through the port normally, but the port remains in forwarding state.
Why wrong: This is false. PortFast does not filter BPDUs; they are still processed. However, the port is in forwarding state from the start.
- D
BPDU Guard prevents the port from becoming a root port or designated port by ignoring superior BPDUs.
Why wrong: This is false. BPDU Guard does not affect the STP election process; it simply disables the port if a BPDU is received.
- E
BPDU Guard is typically configured on trunk ports to prevent loops between switches.
Why wrong: This is false. BPDU Guard is intended for access ports with PortFast, not for trunk ports between switches.
Quick Answer
The correct answer is that BPDU Guard disables a PortFast-enabled port if it receives any BPDU, while PortFast immediately transitions an access port from blocking to forwarding, bypassing the listening and learning states. This works because PortFast is designed for end-device access ports where no switch should be connected, so skipping STP convergence speeds up connectivity; however, if a rogue BPDU is received, the port could create a loop, which is where BPDU Guard steps in by errdisabling the port to protect the network. On the CCNA 200-301 v2 exam, this topic tests your understanding of STP optimization and loop prevention, often appearing in multiple-choice questions that pair these features together. A common trap is assuming PortFast ignores BPDUs—it does not; it still processes them and reverts to normal STP, while BPDU Guard actively shuts the port down. Remember the mnemonic: PortFast skips states, BPDU Guard terminates threats.
CCNA Switching and Network Access Practice Question
This 200-301 practice question tests your understanding of switching and network access. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. 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.
Which TWO statements correctly describe the behavior of PortFast and BPDU Guard on a Cisco switch?
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
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.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 immediately transitions a port from blocking to forwarding state, bypassing listening and learning.
Why this is correct
This is correct. PortFast allows a port to go directly to forwarding, reducing the time a host takes to start sending traffic.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
BPDU Guard disables a PortFast-enabled port if it receives any BPDU.
Why this is correct
This is correct. BPDU Guard err-disables a PortFast port upon receiving a BPDU, protecting against accidental loops.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
PortFast allows BPDUs to pass through the port normally, but the port remains in forwarding state.
Why it's wrong here
This is false. PortFast does not filter BPDUs; they are still processed. However, the port is in forwarding state from the start.
- ✗
BPDU Guard prevents the port from becoming a root port or designated port by ignoring superior BPDUs.
Why it's wrong here
This is false. BPDU Guard does not affect the STP election process; it simply disables the port if a BPDU is received.
- ✗
BPDU Guard is typically configured on trunk ports to prevent loops between switches.
Why it's wrong here
This is false. BPDU Guard is intended for access ports with PortFast, not for trunk ports between switches.
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 immediately transitions a port from blocking to forwarding state, bypassing listening and learning.Correct answer▾
Why this is correct
This is correct. PortFast allows a port to go directly to forwarding, reducing the time a host takes to start sending traffic.
✗PortFast allows BPDUs to pass through the port normally, but the port remains in forwarding state.Wrong answer — click to see why▾
Why this is wrong here
PortFast does not filter BPDUs; it still processes them normally. If a BPDU is received on a PortFast port, the port will still participate in STP and may transition to a blocking state, defeating the purpose of PortFast. The statement incorrectly claims BPDUs pass through while the port remains forwarding, which is not true.
Why candidates choose this
Students may confuse PortFast with BPDU filtering or think that PortFast ignores BPDUs entirely. The phrase 'allows BPDUs to pass through normally' might seem plausible because PortFast does not block BPDUs, but the key error is that the port does not remain in forwarding state if a BPDU is received.
✗BPDU Guard prevents the port from becoming a root port or designated port by ignoring superior BPDUs.Wrong answer — click to see why▾
Why this is wrong here
BPDU Guard does not affect STP election processes; it simply err-disables the port upon receiving any BPDU. It does not ignore superior BPDUs or prevent the port from becoming a root or designated port. That behavior is associated with Root Guard, not BPDU Guard.
Why candidates choose this
The description of 'ignoring superior BPDUs' sounds similar to the function of Root Guard, which prevents a port from becoming a root port. Students often mix up BPDU Guard and Root Guard because both involve BPDU handling and port protection.
✗BPDU Guard is typically configured on trunk ports to prevent loops between switches.Wrong answer — click to see why▾
Why this is wrong here
BPDU Guard is intended for access ports with PortFast, not for trunk ports. Trunk ports between switches are expected to exchange BPDUs for normal STP operation; applying BPDU Guard on a trunk would cause the port to err-disable upon receiving legitimate BPDUs, disrupting the network.
Why candidates choose this
Students might think that BPDU Guard prevents loops, and since trunk ports can be involved in loops, they might assume it is appropriate. However, the correct loop prevention on trunk ports is achieved through STP itself, not BPDU Guard.
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
Cisco often tests the misconception that PortFast itself blocks or filters BPDUs, when in fact it only accelerates the transition to forwarding; BPDU Guard is a separate feature that must be explicitly enabled to disable the port upon BPDU reception.
Detailed technical explanation
How to think about this question
PortFast works by setting the port to an STP port type that skips the listening and learning states, effectively placing it in forwarding state immediately upon link up. BPDU Guard, when enabled globally or per interface, errdisables the port if any BPDU is received, protecting against accidental loops from misconfigured end devices or rogue switches. In real-world scenarios, combining PortFast with BPDU Guard on access ports is a best practice to prevent bridging loops while ensuring fast connectivity for hosts.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
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
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A help-desk technician troubleshoots why a newly connected PC cannot reach shared printers on the same floor. The cable is good, the switch port is active, but the PC is in VLAN 20 and the printers are in VLAN 10. The uplink trunk only allows VLAN 10. A trunk being up does not mean every VLAN crosses it.
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this 200-301 question test?
Switching and Network Access — This question tests Switching and Network Access — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: 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.
What should I do if I get this 200-301 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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 →
Same concept, more angles
1 more ways this is tested on 200-301
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. You are connected to switch SW1. Configure Rapid-PVST+ so that SW1 becomes the root bridge for VLAN 10 and VLAN 20. On interface GigabitEthernet0/2, enable PortFast and BPDUGuard. Then, a BPDU is received on that port, causing err-disable. Diagnose the issue and recover the interface without rebooting the switch.
hard- ✓ A.Configure SW1 as root for VLAN 10 and 20 using 'spanning-tree vlan 10 root primary' and 'spanning-tree vlan 20 root primary'. On Gi0/2, enable PortFast with 'spanning-tree portfast' and BPDUGuard with 'spanning-tree bpduguard enable'. The err-disable state occurs because BPDUGuard shuts down the port when a BPDU is received. To recover, use 'errdisable recovery cause bpduguard' to enable automatic recovery, or manually do 'shutdown' followed by 'no shutdown' on the interface.
- B.Configure SW1 as root for VLAN 10 and 20 using 'spanning-tree vlan 10 root primary' and 'spanning-tree vlan 20 root primary'. On Gi0/2, enable PortFast with 'spanning-tree portfast' and BPDUGuard with 'spanning-tree bpduguard enable'. The err-disable state occurs because BPDUGuard shuts down the port when a BPDU is received. To recover, use 'clear spanning-tree detected-protocols' on the interface.
- C.Configure SW1 as root for VLAN 10 and 20 using 'spanning-tree vlan 10 root primary' and 'spanning-tree vlan 20 root primary'. On Gi0/2, enable PortFast with 'spanning-tree portfast' and BPDUGuard with 'spanning-tree bpduguard enable'. The err-disable state occurs because BPDUGuard shuts down the port when a BPDU is received. To recover, use 'no spanning-tree bpduguard enable' on the interface, then re-enable it.
- D.Configure SW1 as root for VLAN 10 and 20 using 'spanning-tree vlan 10 root primary' and 'spanning-tree vlan 20 root primary'. On Gi0/2, enable PortFast with 'spanning-tree portfast' and BPDUGuard with 'spanning-tree bpduguard enable'. The err-disable state occurs because BPDUGuard shuts down the port when a BPDU is received. To recover, use 'reload' on the switch to reset all interfaces.
Why A: First, configure SW1 as root for VLAN 10 and 20 using 'spanning-tree vlan 10 root primary' and 'spanning-tree vlan 20 root primary'. Then, on interface Gi0/2, enable PortFast with 'spanning-tree portfast' and BPDUGuard with 'spanning-tree bpduguard enable'. The err-disable state occurs because BPDUGuard defaults to shutting down a port when a BPDU is received. To recover, use 'errdisable recovery cause bpduguard' to allow automatic recovery or 'shutdown' followed by 'no shutdown' on the interface. The blocking port is Gi0/2 in VLAN 20 because the current root has a higher priority than SW1's configured priority, but since SW1 becomes root, all ports are designated.
Last reviewed: Jun 11, 2026
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