The answer is a syntax error in the policy-statement 'test' within the protocol match condition. This is correct because the commit check failure message explicitly identifies a syntax issue when Junos attempts to validate the protocol match; the system only accepts predefined protocol names like 'bgp', 'ospf', or 'static', so any misspelling or invalid entry triggers an immediate rejection during the commit check. On the JNCIA-Junos exam, this scenario tests your understanding of policy-options syntax validation and the commit check process, which is a common trap where candidates overlook exact protocol naming. A reliable memory tip is to think of the protocol match as a strict dropdown list—Junos does not guess or autocorrect, so always verify the spelling against the official protocol names in the configuration guide.
JNCIA-JUNOS Junos Configuration Basics Practice Question
This JNCIA-JUNOS practice question tests your understanding of junos configuration basics. 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.
Exhibit
user@router# commit check
error: configuration check-out failed:
syntax error
'1.1.1.1/32'
error: policy-options policy-statement test term 0 from protocol is not valid
Refer to the exhibit. What is the most likely cause of the error?
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.
user@router# commit check
error: configuration check-out failed:
syntax error
'1.1.1.1/32'
error: policy-options policy-statement test term 0 from protocol is not valid
A
The IP address 1.1.1.1/32 is already in use.
Why wrong: The error is about the policy-statement, not the IP address being in use.
B
The candidate configuration has no errors and this is a warning.
Why wrong: It is an error, not a warning, and the commit check failed.
C
The policy-statement 'test' contains a syntax error in the protocol match condition.
The error indicates 'protocol is not valid' in the policy-statement.
D
The commit check command requires user confirmation.
Why wrong: Commit check runs and reports errors without requiring confirmation.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The policy-statement 'test' contains a syntax error in the protocol match condition.
Option C is correct because the error message in the exhibit indicates a syntax error in the policy-statement 'test' when using the protocol match condition. In Junos, the 'protocol' match condition requires a valid protocol name (e.g., 'bgp', 'ospf', 'static'), and if an invalid or misspelled protocol is specified, the commit check fails with a syntax error. This is a common mistake when configuring policy-options, as the Junos CLI validates the protocol against a predefined list.
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.
✗
The IP address 1.1.1.1/32 is already in use.
Why it's wrong here
The error is about the policy-statement, not the IP address being in use.
✗
The candidate configuration has no errors and this is a warning.
Why it's wrong here
It is an error, not a warning, and the commit check failed.
✓
The policy-statement 'test' contains a syntax error in the protocol match condition.
Why this is correct
The error indicates 'protocol is not valid' in the policy-statement.
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.
✗
The commit check command requires user confirmation.
Why it's wrong here
Commit check runs and reports errors without requiring confirmation.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may misinterpret a syntax error as a warning or an IP conflict, because Junos error messages can be verbose, but the key is to identify the specific line number and the 'syntax error' keyword in the output, which points directly to a configuration mistake in the policy-statement.
Detailed technical explanation
How to think about this question
In Junos, policy-options match conditions are case-sensitive and must use exact protocol names as defined in the Junos hierarchy (e.g., 'bgp', 'direct', 'local', 'ospf', 'static', 'rip'). The 'protocol' match condition is used within a 'from' or 'to' stanza of a policy-statement, and if an invalid protocol is entered, the commit check fails with a syntax error because the Junos parser cannot map the string to a valid protocol identifier. This is different from Cisco IOS, where policy matching often uses route-map and ACLs with less strict validation at commit time.
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 network engineer at a university connects two campus buildings via a fibre link. Both routers run OSPF, but no adjacency forms — even though both routers can ping each other. The engineer finds one router is in area 0 and the other in area 1. OSPF adjacency requires matching area numbers, hello/dead timers, and network type. IP reachability alone is not enough.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Junos Configuration Basics — This question tests Junos Configuration Basics — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The policy-statement 'test' contains a syntax error in the protocol match condition. — Option C is correct because the error message in the exhibit indicates a syntax error in the policy-statement 'test' when using the protocol match condition. In Junos, the 'protocol' match condition requires a valid protocol name (e.g., 'bgp', 'ospf', 'static'), and if an invalid or misspelled protocol is specified, the commit check fails with a syntax error. This is a common mistake when configuring policy-options, as the Junos CLI validates the protocol against a predefined list.
What should I do if I get this JNCIA-JUNOS 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.
About these practice questions
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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. Refer to the exhibit. What is the most likely cause of the commit check failure?
medium
A.The routing instance has not been created.
✓ B.The interface xe-0/0/0 has been disabled using the 'disable' statement.
C.The IP address is a duplicate on the subnet.
D.The 'family inet' statement is missing under unit 0.
Why B: The commit check failure occurs because the interface xe-0/0/0 is configured with the 'disable' statement, which prevents the interface from being enabled. When a routing instance references a disabled interface, the commit check fails because the interface cannot be used for forwarding or routing operations. Junos requires that interfaces referenced in routing instances be operationally capable of being enabled.
Last reviewed: Jun 24, 2026
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