The answer is that the switch runs a different IOS version with different VLAN CLI syntax. This is the most likely cause because Ansible automates network configuration by sending commands over SSH exactly as written in the playbook; if the target switch expects a different command format—such as 'vlan database' on older CatOS versus 'vlan 10' on modern IOS—the device will reject the command as unrecognized, causing the task to fail. On the ENCOR 350-401 exam, this scenario tests your understanding of automation pitfalls when managing heterogeneous network environments, often appearing as a trap where you might blame connectivity or privilege issues instead of syntax differences. A key memory tip is to think "CLI dialect mismatch"—just as spoken languages vary by region, IOS versions speak different command dialects, so always verify the target’s IOS version before running Ansible VLAN tasks.
350-401 Automation Practice Question
This 350-401 practice question tests your understanding of automation. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
A network engineer is automating the deployment of VLANs across multiple switches using Ansible. The playbook runs successfully on most switches, but one switch fails with an error indicating that the VLAN configuration command is not recognized. 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.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The switch runs a different IOS version with different VLAN CLI syntax
The most likely cause is that the switch runs a different IOS version with different VLAN CLI syntax. Ansible executes commands via SSH, and if the switch expects a different command format (e.g., 'vlan 10' vs. 'vlan database' on older CatOS), the playbook will fail with a command-not-recognized error. This is a common issue when automating across heterogeneous network devices.
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.
✗
Ansible lacks the appropriate module for VLAN configuration
Why it's wrong here
Ansible's ios_vlan module supports VLAN creation; if missing, all switches would fail.
✗
The inventory file has a syntax error for that specific host
Why it's wrong here
Ansible validates the inventory before running; a syntax error would cause a parse error, not a per-host CLI error.
✓
The switch runs a different IOS version with different VLAN CLI syntax
Why this is correct
VLAN configuration syntax can vary between IOS versions; the playbook may use commands not supported on that version.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
SSH connectivity to the switch is blocked by an ACL
Why it's wrong here
If SSH were blocked, the playbook would fail on all hosts, not just one.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may assume a module or connectivity issue, but Cisco tests the understanding that different IOS versions or platforms (e.g., IOS vs. CatOS) have distinct VLAN CLI syntax, which Ansible modules must handle via conditional logic or version-specific variables.
Detailed technical explanation
How to think about this question
Cisco IOS and IOS-XE use 'vlan <id>' in global configuration mode, while older CatOS uses 'set vlan <id>' or 'vlan database' mode. Ansible's ios_vlan module translates the desired state into the correct CLI for the target OS version, but if the switch runs a non-standard or legacy image, the module may generate an unsupported command. In real-world scenarios, this often occurs when a single playbook targets a mix of Catalyst 2960 (IOS) and Catalyst 6500 (CatOS) switches without proper host_vars or group_vars to differentiate syntax.
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 350-401 question in full detail.
Automation — This question tests Automation — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The switch runs a different IOS version with different VLAN CLI syntax — The most likely cause is that the switch runs a different IOS version with different VLAN CLI syntax. Ansible executes commands via SSH, and if the switch expects a different command format (e.g., 'vlan 10' vs. 'vlan database' on older CatOS), the playbook will fail with a command-not-recognized error. This is a common issue when automating across heterogeneous network devices.
What should I do if I get this 350-401 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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?
Read the scenario before looking for a memorised answer.
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Question Discussion
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