Question 1,181 of 1,819
Switching and Network AccessmediumMultiple SelectObjective-mapped

VLAN Configuration, 802.1Q Trunking, and Native VLAN Best Practices

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 are true regarding VLAN configuration, 802.1Q trunking, and the native VLAN?

Quick Answer

The correct answer includes two statements: changing the native VLAN from the default VLAN 1 to an unused VLAN is a security best practice, and 802.1Q supports up to 4094 VLANs (IDs 1–4094). The first is true because altering the native VLAN helps prevent VLAN hopping attacks, where an attacker can exploit the default VLAN 1 to gain unauthorized access across trunk links. The second is correct because 802.1Q uses a 12-bit VLAN ID field, which allows for 4096 possible values, but IDs 0 and 4095 are reserved, leaving 1 through 4094 for actual VLANs. On the CCNA 200-301 v2 exam, this topic tests your understanding of VLAN trunking native VLAN best practices, often appearing in questions that mix security recommendations with protocol specifications. A common trap is assuming the native VLAN must match on both ends of a trunk—it does not, but mismatches can cause traffic misclassification. Remember the mnemonic: “Change the native, keep it vacant” to recall that an unused native VLAN is a key security step.

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 native VLAN should be changed from the default VLAN 1 to an unused VLAN for security reasons.

Option B is correct because changing the native VLAN from the default VLAN 1 to an unused VLAN is a recommended security best practice to prevent VLAN hopping attacks. Option D is correct because 802.1Q uses a 12-bit VLAN ID field, allowing VLAN IDs from 1 to 4094 (0 and 4095 are reserved). Option A is false: on an 802.1Q trunk, frames in the native VLAN are typically sent untagged. Option C is false: 802.1Q is an IEEE standard, not Cisco proprietary (ISL is Cisco proprietary). Option E is false: the native VLAN does not have to match on both ends; mismatched native VLANs can cause traffic to be misclassified but the trunk will still operate.

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.

  • On an 802.1Q trunk, frames in the native VLAN are always tagged with a VLAN ID.

    Why it's wrong here

    This is false. Frames in the native VLAN are not tagged; they are sent untagged on an 802.1Q trunk.

  • The native VLAN should be changed from the default VLAN 1 to an unused VLAN for security reasons.

    Why this is correct

    Changing the native VLAN away from VLAN 1 is a security best practice to prevent VLAN hopping and reduce the risk of attacks that exploit the default native VLAN.

    Related concept

    Read the scenario before looking for a memorised answer.

  • 802.1Q is a Cisco proprietary trunking protocol.

    Why it's wrong here

    802.1Q is an IEEE standard (industry standard), not a Cisco proprietary protocol. ISL is Cisco proprietary, but it is obsolete.

  • 802.1Q supports up to 4094 VLANs (VLAN IDs 1–4094).

    Why this is correct

    802.1Q uses a 12-bit VLAN ID field, allowing for 4096 possible values (0–4095), but VLANs 0 and 4095 are reserved, leaving 1–4094 usable.

    Related concept

    Read the scenario before looking for a memorised answer.

  • The native VLAN must be the same on both ends of an 802.1Q trunk for the trunk to operate.

    Why it's wrong here

    While it is strongly recommended for proper operation, it is not strictly required for the trunk to pass traffic; however, mismatched native VLANs can cause serious issues like VLAN leakage and should be avoided.

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 native VLAN should be changed from the default VLAN 1 to an unused VLAN for security reasons.Correct answer

Why this is correct

Changing the native VLAN away from VLAN 1 is a security best practice to prevent VLAN hopping and reduce the risk of attacks that exploit the default native VLAN.

On an 802.1Q trunk, frames in the native VLAN are always tagged with a VLAN ID.Wrong answer — click to see why

Why this is wrong here

The native VLAN is specifically the VLAN that does not get a tag; all other VLANs are tagged.

802.1Q is a Cisco proprietary trunking protocol.Wrong answer — click to see why

Why this is wrong here

802.1Q is an open standard, whereas ISL was Cisco proprietary.

The native VLAN must be the same on both ends of an 802.1Q trunk for the trunk to operate.Wrong answer — click to see why

Why this is wrong here

Mismatched native VLANs can lead to security vulnerabilities and misrouting, but the trunk itself may still come up.

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 802.1Q is proprietary (it is not) and that native VLAN frames are always tagged (they are untagged by default), leading candidates to incorrectly select options A or C.

Detailed technical explanation

How to think about this question

The native VLAN is a concept in 802.1Q trunking where frames belonging to that VLAN are transmitted without a VLAN tag to maintain backward compatibility with devices that do not understand trunking. When a switch receives an untagged frame on a trunk port, it assigns it to the native VLAN. Changing the native VLAN to an unused VLAN mitigates the risk of VLAN hopping attacks, as an attacker would need to know the native VLAN ID to successfully inject double-tagged frames.

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.

Visual reference

Switch VLAN 10 Sales (192.168.10.0/24) PC-A PC-B VLAN 20 HR (192.168.20.0/24) PC-C PC-D Router VLANs isolate traffic — inter-VLAN routing requires a Layer 3 device

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: The native VLAN should be changed from the default VLAN 1 to an unused VLAN for security reasons. — Option B is correct because changing the native VLAN from the default VLAN 1 to an unused VLAN is a recommended security best practice to prevent VLAN hopping attacks. Option D is correct because 802.1Q uses a 12-bit VLAN ID field, allowing VLAN IDs from 1 to 4094 (0 and 4095 are reserved). Option A is false: on an 802.1Q trunk, frames in the native VLAN are typically sent untagged. Option C is false: 802.1Q is an IEEE standard, not Cisco proprietary (ISL is Cisco proprietary). Option E is false: the native VLAN does not have to match on both ends; mismatched native VLANs can cause traffic to be misclassified but the trunk will still operate.

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.

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Last reviewed: Jun 11, 2026

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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.