CCNA Switching and Network Access Practice Question
Exhibit
SW2# show vlan brief
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Gi0/1, Gi0/3, Gi0/4, Gi0/5
Gi0/6, Gi0/7, Gi0/8
10 Sales active Gi0/9, Gi0/10, Gi0/11
20 Engineering active Gi0/12, Gi0/13
30 Management active Gi0/14
1002 fddi-default act/unsup
1003 token-ring-default act/unsup
1004 fddinet-default act/unsup
1005 trnet-default act/unsupRefer to the exhibit. A network administrator runs the show vlan brief command on SW2. Interface GigabitEthernet0/2 is intended to be an access port in VLAN 10, but it does not appear in the output. What is the most likely cause?
⚠ Common exam trap
Cisco often tests the distinction between access and trunk port behavior in `show vlan brief` output, trapping candidates who assume all switchports appear in the VLAN listing regardless of mode.
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
✓
The interface is configured as a trunk port and therefore does not appear under any VLAN in show vlan brief.
The `show vlan brief` command displays only access ports and their assigned VLANs. Trunk ports, which carry multiple VLANs, are not listed in this output. If GigabitEthernet0/2 is configured as a trunk port (e.g., with `switchport mode trunk` or dynamically via DTP), it will not appear under any VLAN in the `show vlan brief` output, even if it is intended to be an access port in VLAN 10.
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 interface is configured with switchport mode dynamic auto and no trunk has been negotiated, causing it to be hidden.
Why it's wrong here
A port in dynamic auto mode begins as an access port and will appear in show vlan brief under the default VLAN until negotiation turns it into a trunk. It is not hidden from the output.
- ✗
The interface is administratively shut down, and down ports are excluded from the show vlan brief output.
Why it's wrong here
Administratively shutting down an interface does not remove it from the show vlan brief output. The command displays the configured access VLAN membership for each port, independent of the link state or administrative status. A shutdown access port still appears in its assigned VLAN because the access VLAN assignment remains in the running configuration. Therefore, Gi0/2 would not be hidden simply because it was administratively down.
- ✓
The interface is configured as a trunk port and therefore does not appear under any VLAN in show vlan brief.
Why this is correct
show vlan brief only displays ports that are in access mode. Trunk ports are not included because they belong to all VLANs allowed on the trunk. The output shows VLAN 10 with members Gi0/9–Gi0/11 but not Gi0/2, confirming it is not an access port.
- ✗
VLAN 10 is not active, so the port assigned to it is not displayed in the listing.
Why it's wrong here
The show vlan brief command only lists VLANs that are active in the VLAN database; if VLAN 10 were shut down or suspended, the entire VLAN row would be absent. In the exhibit, though, VLAN 10 is shown as active and already includes member ports Gi0/9, Gi0/10, and Gi0/11. Since the VLAN is active, an access port assigned to it would appear in that same row, so the claim that Gi0/2 is omitted because VLAN 10 is inactive is directly contradicted by the output.
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 interface is configured as a trunk port and therefore does not appear under any VLAN in show vlan brief.Correct answer▾
Why this is correct
show vlan brief only displays ports that are in access mode. Trunk ports are not included because they belong to all VLANs allowed on the trunk. The output shows VLAN 10 with members Gi0/9–Gi0/11 but not Gi0/2, confirming it is not an access port.
✗The interface is configured with switchport mode dynamic auto and no trunk has been negotiated, causing it to be hidden.Wrong answer — click to see why▾
Why this is wrong here
Confusion about how dynamic trunking protocol (DTP) modes interact with VLAN membership display.
✗The interface is administratively shut down, and down ports are excluded from the show vlan brief output.Wrong answer — click to see why▾
Why this is wrong here
Misconception that only operational interfaces are shown in VLAN membership tables.
✗VLAN 10 is not active, so the port assigned to it is not displayed in the listing.Wrong answer — click to see why▾
Why this is wrong here
Overlooking the explicit 'active' status and port list for VLAN 10 in the output.
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
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Related to this question
Learn chapter
Configuring Switch Ports for Desktops, VoIP Phones, APs, IoT, and Virtualized Hosts
Key term
VLAN
A VLAN logically segments a physical network into isolated broadcast domains without requiring separate physical switches.
Key term
Trunk port
A trunk port is a switch port configured to carry traffic for multiple VLANs, using a tagging protocol to identify which VLAN each frame belongs to.
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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.