JN0-106 · domain
Operational Monitoring and Maintenance
Practise Juniper Networks Certified Associate Junos JNCIA-Junos Operational Monitoring and Maintenance practice questions — original exam-style scenarios with answer choices, explanations, and analysis of common mistakes.
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What this domain covers
What to know about Operational Monitoring and Maintenance
Operational Monitoring and Maintenance questions test whether you can apply the concept in context, not just recognise a definition.
How the topic appears in realistic exam-style scenarios.
Which detail in the question changes the correct answer.
How to eliminate plausible but wrong options.
How to connect the question back to the wider exam objective.
Watch out for
Common Operational Monitoring and Maintenance exam traps
- ▸Answering from memory before reading the full scenario.
- ▸Missing a constraint such as cost, availability, security, scope or command context.
- ▸Choosing a broad answer when the question asks for the most specific fix.
- ▸Ignoring why the wrong options are tempting.
Question index
All Operational Monitoring and Maintenance questions (23)
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Refer to the exhibit. Which interface has a physical layer connectivity problem?
Easy2A network operator needs to upgrade the Junos OS on the backup RE (re1) of a dual-RE system. Which procedure ensures that only the backup RE is upgraded and rebooted without affecting the forwarding plane?
Hard3A network administrator wants to see the current CPU load average over the last 1, 5, and 15 minutes on a Juniper device. Which command displays this information?
Easy4You are managing a Juniper MX240 router at a small ISP. The router has been operating normally for months. This morning, a customer reports intermittent packet loss on their connection, which is served by interface ge-0/0/2. You SSH into the router and run 'show interfaces ge-0/0/2 extensive'. The output shows input errors increasing rapidly, including CRC errors and frame errors. The interface is up/up. You also notice that the interface statistics show a high number of carrier transitions. The cable connecting the router to the customer's CPE was recently replaced by the customer's technician. What is the most likely cause of the errors and the correct action to resolve the issue?
Easy5Which TWO commands can be used to monitor system log messages in real-time?
Medium6An administrator is asked to check the system log files for any error messages related to interface failures. Which command would be most efficient?
Easy7Your company runs a Juniper MX480 router as the core gateway. The router has been experiencing intermittent connectivity issues with a remote site over a point-to-point OC3 link. Users report that the link goes down for a few seconds several times a day. You suspect that the issue might be related to physical layer errors or framing. You need to determine the cause and collect relevant data to present to the service provider. Which course of action should you take first?
Hard8Which two commands can be used to monitor real-time interface statistics and errors on a Junos device?
Medium9An engineer needs to check if the device has any pending changes that have not been committed. Which operational command should they run?
Hard10Which command is used to verify that the current active configuration is the same as the candidate configuration?
Medium11You are managing a Juniper MX router that serves as a BGP route reflector for multiple customer VPNs. The router has two routing engines (RE0 and RE1) in a graceful switchover (GRES) configuration. During a routine maintenance window, you need to upgrade the Junos OS from version 18.1R1 to 20.2R2. The upgrade must minimize traffic disruption. You have already staged the new image on both REs. Which sequence of commands ensures minimal impact?
Hard12Refer to the exhibit. An administrator notices the /var partition is nearly full. Which command can be used to safely reclaim disk space?
Easy13Which TWO commands can be used to view the current routing table entries for IPv4 unicast routes?
Hard14A technician needs to view the last 50 log messages from the system log file. Which command accomplishes this?
Easy15A technician notices that the /var partition is filling up on a Juniper device. Which action would be most appropriate to free up space while preserving critical logs?
Medium16Which command displays the status of all configured interfaces, including administrative and operational status?
Easy17A network engineer suspects a hardware issue on an interface. Which command provides the most detailed hardware error counters, including CRC errors, framing errors, and runts?
Medium18Which TWO commands can be used to view the system log messages on a Juniper device? (Select two.)
Easy19An operator wants to monitor the temperature and voltage sensors on a Juniper chassis. Which command displays current sensor readings?
Hard20A network administrator notices that the CPU utilization on an MX240 router has been consistently above 90% for the past hour. Users are reporting intermittent connectivity issues. The administrator logs in and runs 'show system processes extensive' which shows the Routing Protocol Daemon (rpd) consuming 70% of the CPU. Further investigation reveals that the router has over 5000 BGP prefixes from multiple peers. The administrator suspects that the high CPU is due to continuous route processing. What should the administrator do to immediately reduce CPU load while maintaining network stability?
Easy21Refer to the exhibit. Based on the log messages, what is the most likely cause of the interface flapping?
Hard22Which two events typically trigger a change to the routing table? (Choose two.)
Medium23You are a junior network engineer tasked with upgrading the Junos OS on a pair of EX3400 switches that are in a Virtual Chassis. You have downloaded the new software image to the primary switch. Before performing the upgrade, you must verify the image's integrity and check the current version. Which sequence of commands should you use?
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Frequently asked questions
- What does the Operational Monitoring and Maintenance domain cover on the JN0-106 exam?
- Operational Monitoring and Maintenance questions test whether you can apply the concept in context, not just recognise a definition.
- How many questions are in this domain?
- This page lists all 23 Operational Monitoring and Maintenance questions in the JN0-106 question bank. The actual exam draws from this domain proportionally to its weighting in the official exam blueprint.
- What is the best way to practise this domain?
- Start with a short focused session (10 questions) to identify gaps, then work through explanations. Repeat with a longer session once the weak areas feel solid.
- Can I practise only Operational Monitoring and Maintenance questions?
- Yes — the session launcher on this page filters questions to this domain only. Choose any session length for inline explanations and scoring.