The answer is that PortFast does not skip the listening and learning states on a trunk port because PortFast is only active on access ports by default. When a switchport is configured as a trunk, the switch disables PortFast regardless of the interface-level command, leaving the port to follow the normal spanning-tree transition through listening and learning for the full forward delay period. This tests your understanding of the CCNA 200-301 v2 exam objective on spanning-tree features, where a common trap is assuming PortFast works on any port type. The key is that PortFast is designed for edge ports connecting end hosts, not for trunk links that carry multiple VLANs and must participate fully in STP convergence. A useful memory tip: "PortFast is for access, not for trunks that pass."
CCNA Switching and Network Access Practice Question
This 200-301 practice question tests your understanding of switching and network access. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. 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.
Exhibit
SW1# show spanning-tree vlan 10 detail
VLAN0010 is executing the ieee compatible Spanning Tree protocol
Bridge Identifier has priority 32768, address aabb.cc00.0200
Configured hello time 2, max age 20, forward delay 15
Current root has priority 32768, address aabb.cc00.0100
Root port is GigabitEthernet0/2, cost of root path is 4
Topology change flag not set, detected flag not set
Number of topology changes 2 last change occurred 00:05:30 ago
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0
Port 13 (GigabitEthernet0/1) of VLAN0010 is listening
Port path cost 4, Port priority 128, Port Identifier 128.13
Designated root has priority 32768, address aabb.cc00.0100
Designated bridge has priority 32768, address aabb.cc00.0200
Designated port id is 128.13, designated path cost 0
Timers: message age 0, forward delay 12, hold 0
Number of transitions to forwarding state: 0
Link type is point-to-point by default
BPDU: sent 2, received 0
Edge port: no (default) portfast: no (default)
Refer to the exhibit. An engineer configured PortFast on interface GigabitEthernet0/1, which connects to a server that does not participate in spanning tree. However, the port remains in the listening state for the full forward delay period before transitioning to forwarding. The engineer issues the show spanning-tree vlan 10 detail command. Based on the output, what is the most likely cause?
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.
SW1# show spanning-tree vlan 10 detail
VLAN0010 is executing the ieee compatible Spanning Tree protocol
Bridge Identifier has priority 32768, address aabb.cc00.0200
Configured hello time 2, max age 20, forward delay 15
Current root has priority 32768, address aabb.cc00.0100
Root port is GigabitEthernet0/2, cost of root path is 4
Topology change flag not set, detected flag not set
Number of topology changes 2 last change occurred 00:05:30 ago
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0
Port 13 (GigabitEthernet0/1) of VLAN0010 is listening
Port path cost 4, Port priority 128, Port Identifier 128.13
Designated root has priority 32768, address aabb.cc00.0100
Designated bridge has priority 32768, address aabb.cc00.0200
Designated port id is 128.13, designated path cost 0
Timers: message age 0, forward delay 12, hold 0
Number of transitions to forwarding state: 0
Link type is point-to-point by default
BPDU: sent 2, received 0
Edge port: no (default) portfast: no (default)
A
The port is configured as a trunk, so PortFast is not active.
PortFast is only effective on access ports. The exhibit shows ‘Edge port: no (default) portfast: no (default)’ despite the engineer enabling PortFast, indicating the port is operating as a trunk (or not an access port). Therefore, PortFast has no effect and the normal STP listening/learning states apply.
B
BPDU Guard is enabled on the port, causing it to block.
Why wrong: BPDU Guard would place the port into an err-disabled state if a BPDU is received, not into the listening state. The exhibit shows the port in listening, not err-disabled, and no BPDU Guard indication.
C
The forward delay timer is set too high, and PortFast cannot override it.
Why wrong: PortFast is designed to skip the listening and learning states regardless of the forward delay timer value. The issue is not the timer value but that PortFast is not active.
D
The server is sending BPDUs, causing the port to lose its PortFast state.
Why wrong: If the port received a BPDU after PortFast enabled, it would lose PortFast and revert to normal STP states. However, the exhibit shows ‘BPDU: received 0’ (no BPDUs received), so this is not the cause.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The port is configured as a trunk, so PortFast is not active.
The exhibit shows that GigabitEthernet0/1 is in ‘listening’ state with a forward delay timer of 12 seconds, and the lines ‘Edge port: no (default) portfast: no (default)’ indicate that PortFast is disabled. PortFast only takes effect on access ports; since the port is configured as a trunk (implied by the disconnected state of PortFast despite the engineer’s configuration), it does not skip listening/learning. The port is not in err-disabled state (no BPDU Guard block), and no BPDUs have been received (BPDU: received 0), ruling out other options.
Key principle: A trunk being up does not mean the VLAN is allowed across it. Always verify the allowed VLAN list and whether the VLAN exists on both switches.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
The port is configured as a trunk, so PortFast is not active.
Why this is correct
PortFast is only effective on access ports. The exhibit shows ‘Edge port: no (default) portfast: no (default)’ despite the engineer enabling PortFast, indicating the port is operating as a trunk (or not an access port). Therefore, PortFast has no effect and the normal STP listening/learning states apply.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Access ports place end devices into a single VLAN.
✗
BPDU Guard is enabled on the port, causing it to block.
Why it's wrong here
BPDU Guard would place the port into an err-disabled state if a BPDU is received, not into the listening state. The exhibit shows the port in listening, not err-disabled, and no BPDU Guard indication.
✗
The forward delay timer is set too high, and PortFast cannot override it.
Why it's wrong here
PortFast is designed to skip the listening and learning states regardless of the forward delay timer value. The issue is not the timer value but that PortFast is not active.
✗
The server is sending BPDUs, causing the port to lose its PortFast state.
Why it's wrong here
If the port received a BPDU after PortFast enabled, it would lose PortFast and revert to normal STP states. However, the exhibit shows ‘BPDU: received 0’ (no BPDUs received), so this is not the cause.
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.
✓The port is configured as a trunk, so PortFast is not active.Correct answer▾
Why this is correct
PortFast is only effective on access ports. The exhibit shows ‘Edge port: no (default) portfast: no (default)’ despite the engineer enabling PortFast, indicating the port is operating as a trunk (or not an access port). Therefore, PortFast has no effect and the normal STP listening/learning states apply.
✗BPDU Guard is enabled on the port, causing it to block.Wrong answer — click to see why▾
Why this is wrong here
The port is not in an err-disabled state; BPDU Guard causes the port to be shut down, not to stay in listening.
✗The forward delay timer is set too high, and PortFast cannot override it.Wrong answer — click to see why▾
Why this is wrong here
Misunderstanding that PortFast bypasses timers completely on access ports; the high forward delay is irrelevant if PortFast were active.
✗The server is sending BPDUs, causing the port to lose its PortFast state.Wrong answer — click to see why▾
Why this is wrong here
The assumption that the server is sending BPDUs is contradicted by the output showing zero BPDUs received.
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: an active trunk can still block the VLAN you need
A trunk being up does not prove every VLAN is crossing it. Check allowed VLAN lists, native VLAN mismatch, VLAN existence and access-port assignment.
Trap categories for this question
Command / output trap
BPDU Guard would place the port into an err-disabled state if a BPDU is received, not into the listening state. The exhibit shows the port in listening, not err-disabled, and no BPDU Guard indication.
Detailed technical explanation
How to think about this question
VLAN questions usually combine access-port and trunking clues. The key is to identify whether the issue is local to one switchport, caused by the trunk, or caused by the VLAN not existing where it needs to exist.
KKey Concepts to Remember
Access ports place end devices into a single VLAN.
Trunk ports carry multiple VLANs between switches.
Allowed VLAN lists decide which VLANs can cross a trunk.
Native VLAN mismatch can create confusing symptoms.
TExam Day Tips
→Use show vlan brief to verify access VLANs.
→Use show interfaces trunk to verify trunk state and allowed VLANs.
→Do not treat every same-VLAN issue as a routing problem.
Key takeaway
A trunk being up does not mean the VLAN is allowed across it. Always verify the allowed VLAN list and whether the VLAN exists on both switches.
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.
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 VLAN allowed lists, native VLAN mismatch detection, and how to verify VLAN membership with show vlan brief and show interfaces trunk. Then practise related 200-301 questions on switching, trunking, and access-port configuration.
Switching and Network Access — This question tests Switching and Network Access — Access ports place end devices into a single VLAN..
What is the correct answer to this question?
The correct answer is: The port is configured as a trunk, so PortFast is not active. — The exhibit shows that GigabitEthernet0/1 is in ‘listening’ state with a forward delay timer of 12 seconds, and the lines ‘Edge port: no (default) portfast: no (default)’ indicate that PortFast is disabled. PortFast only takes effect on access ports; since the port is configured as a trunk (implied by the disconnected state of PortFast despite the engineer’s configuration), it does not skip listening/learning. The port is not in err-disabled state (no BPDU Guard block), and no BPDUs have been received (BPDU: received 0), ruling out other options.
What should I do if I get this 200-301 question wrong?
Review VLAN allowed lists, native VLAN mismatch detection, and how to verify VLAN membership with show vlan brief and show interfaces trunk. Then practise related 200-301 questions on switching, trunking, and access-port configuration.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". 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?
Access ports place end devices into a single VLAN.
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