hardMultiple SelectObjective-mapped
VTP Pruning and Manual VLAN Pruning on Trunks
Which three statements about trunking and VLAN pruning are true? (Choose three.)
Quick Answer
The correct answer is that manual VLAN pruning using the 'switchport trunk allowed vlan' command overrides VTP pruning for that specific trunk interface. This is because VTP pruning dynamically removes VLANs from trunk allowed lists to reduce unnecessary broadcast traffic, but it only operates when VTP is in server or transparent mode and does not affect the native VLAN. On the ENCOR 350-401 exam, this concept tests your understanding of how VTP pruning interacts with manual configuration, often appearing in a "choose three" question where you must distinguish between global VTP pruning behavior and per-interface overrides. A common trap is assuming VTP pruning applies to all VLANs equally, but remember that the native VLAN is always allowed and manual pruning takes precedence. Memory tip: "Manual overrides dynamic—if you prune by hand, VTP takes a stand."
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
✓
VTP pruning reduces unnecessary broadcast traffic by preventing a trunk from carrying traffic for VLANs that have no active ports in the VLAN on downstream switches.
VTP pruning reduces unnecessary broadcast traffic on trunk links by dynamically removing VLANs from trunk allowed lists when no downstream switch has ports in that VLAN. VTP pruning is enabled globally with the 'vtp pruning' command. It requires VTP to be in server or transparent mode; clients cannot enable pruning. The 'switchport trunk allowed vlan' command can manually prune VLANs, and this overrides VTP pruning for that interface. VTP pruning does not affect the native VLAN, which is always allowed.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
VTP pruning reduces unnecessary broadcast traffic by preventing a trunk from carrying traffic for VLANs that have no active ports in the VLAN on downstream switches.
Why this is correct
This is the primary benefit of VTP pruning; it dynamically prunes VLANs from trunk links.
- ✓
VTP pruning is enabled globally using the 'vtp pruning' command in global configuration mode.
Why this is correct
The command 'vtp pruning' enables pruning for the entire VTP domain.
- ✗
VTP pruning can be enabled on a VTP client switch.
Why it's wrong here
VTP clients cannot enable pruning; they only receive pruning information from the server. Pruning must be configured on the VTP server.
- ✓
Manual VLAN pruning using 'switchport trunk allowed vlan' overrides VTP pruning for that specific trunk interface.
Why this is correct
If a manual allowed VLAN list is configured, VTP pruning will not remove those VLANs from the trunk, as manual configuration takes precedence.
- ✗
VTP pruning can remove the native VLAN from a trunk link.
Why it's wrong here
The native VLAN is always allowed on a trunk and cannot be pruned by VTP pruning.
Visual reference
Go deeper
Related to this question
About these practice questions
Courseiva writes every 350-401 question from scratch — 1,175 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
Same concept, more angles
1 more way this is tested on 350-401
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. Which three statements about trunking and VLAN pruning are true? (Choose three.)
medium- ✓ A.VTP pruning dynamically removes VLANs from a trunk if the VLAN is not present on the remote switch.
- ✓ B.Manual pruning can be achieved using the 'switchport trunk allowed vlan' command.
- ✓ C.VTP pruning requires VTP to be enabled on the switches in the management domain.
- D.VTP pruning is only supported in VTP version 3.
- E.The 'switchport trunk native vlan' command is used to prune VLANs from a trunk.
Why A: Correct: A is true because VTP pruning reduces unnecessary broadcast traffic on trunk links by dynamically removing VLANs that are not needed on a switch. B is true because pruning can be manually configured on a trunk using the 'switchport trunk allowed vlan' command to restrict which VLANs traverse the link. C is true because VTP pruning requires VTP to be configured and operating in the domain; it is not available without VTP. D is incorrect because VTP pruning works with VTP versions 1 and 2, not just version 3. E is incorrect because the 'switchport trunk native vlan' command sets the native VLAN, not pruning; pruning is controlled by allowed VLAN lists or VTP pruning.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-401 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 350-401 exam.