JN0-106 Operational Monitoring and Maintenance Practice Test 5 — 15 Questions

Question 1

A 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?

Accepted Answer

show system uptime. The 'show system uptime' command displays the system's uptime along with the load averages for the last 1, 5, and 15 minutes. This is the standard Junos command for viewing CPU load averages, which are calculated based on the number of processes in the run queue over those time intervals.

Answer

show chassis routing-engine

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show system processes

Answer

show system statistics

Question 2

A 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?

Accepted Answer

Run 'request system storage cleanup'. The 'request system storage cleanup' command is the correct action because it safely removes non-essential files such as old log files, core dumps, and temporary files that are no longer needed, while preserving critical logs and configuration files. This command performs a controlled cleanup without risking the deletion of important operational data, making it the most appropriate method for freeing up space on the /var partition.

Answer

Delete core files manually

Answer

Reboot the device

Answer

Delete all files in /var/log

Question 3

A 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?

Accepted Answer

Use 'request system software add re1' and then 'request system reboot re1'. The 'request system software add re1' command installs the Junos OS image only on the backup Routing Engine (RE1), and the subsequent 'request system reboot re1' reboots only that RE. In a dual-RE system, this procedure isolates the upgrade to the backup RE, ensuring the forwarding plane remains active on the primary RE (RE0) and no traffic disruption occurs.

Answer

Use 'request system software add <image> both' and then 'request system reboot both'

Answer

Use 'request system software add <image> re0' and then 'request system reboot re0'

Answer

Copy the image to both REs and reboot the backup RE with 'request system reboot slice 1'

Question 4

Which command displays the status of all configured interfaces, including administrative and operational status?

Accepted Answer

show interfaces terse. The 'show interfaces terse' command displays a concise summary of all interfaces, including their administrative status (up or down) and operational status (up or down), along with protocol states. This makes it the correct choice for quickly viewing the status of all configured interfaces in a single output.

Answer

show configuration interfaces

Answer

show chassis hardware

Answer

show interface statistics

Question 5

A 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?

Accepted Answer

show interfaces extensive. The 'show interfaces extensive' command provides the most detailed hardware error counters for a Junos interface, including CRC errors, framing errors, and runts. This command displays per-interface statistics at the physical layer, such as input errors, output errors, and specific error types like frame, runts, giants, and CRC errors, which are essential for diagnosing hardware issues.

Answer

show interfaces diagnostics optics

Answer

show interfaces detail

Answer

show log messages

Question 6

An operator wants to monitor the temperature and voltage sensors on a Juniper chassis. Which command displays current sensor readings?

Accepted Answer

show chassis environment. The 'show chassis environment' command displays real-time sensor readings for temperature, voltage, and fan status on Juniper devices. It is the standard operational command for monitoring chassis environmental health, directly matching the operator's requirement to check temperature and voltage sensors.

Answer

show chassis hardware

Answer

show system health

Answer

show log messages | match temperature

Question 7

A technician needs to view the last 50 log messages from the system log file. Which command accomplishes this?

Accepted Answer

show log messages | last 50. The 'show log messages | last 50' command displays the last 50 lines from the /var/log/messages file on a Junos device. The pipe to 'last' is a Junos CLI filter that outputs only the final N lines of the command output, which is exactly what is needed to view the most recent log entries.

Answer

show system log messages

Answer

monitor start messages

Answer

show system syslog

Question 8

Which command is used to verify that the current active configuration is the same as the candidate configuration?

Accepted Answer

show | compare. The command `show | compare` displays the differences between the candidate configuration and the active (committed) configuration. If there are no differences, the candidate configuration is identical to the active configuration. This is the correct way to verify whether the candidate configuration matches the active configuration in Junos.

Answer

commit check

Answer

show configuration

Answer

show system configuration

Question 9

Which TWO commands can be used to view the current routing table entries for IPv4 unicast routes?

Accepted Answer

show route table inet.0. `show route table inet.0` explicitly displays the IPv4 unicast routing table (inet.0) in Junos. Option D is correct because `show route` without any filter defaults to showing all routes in the inet.0 table, which is the primary IPv4 unicast routing table.

Answer

show route protocol static

Answer

show forwarding-table

Answer

show route table inet6.0

Question 10

Refer to the exhibit. An administrator notices the /var partition is nearly full. Which command can be used to safely reclaim disk space?

Accepted Answer

request system storage cleanup. The 'request system storage cleanup' command safely removes old log files, core dumps, and other temporary files that are no longer needed, freeing up space on the /var partition without risking system stability. This is the recommended Junos method for reclaiming disk space because it targets only files that can be safely deleted.

Answer

request system reboot

Answer

delete /var/log/messages

Answer

request system software delete

Question 11

Refer to the exhibit. Which interface has a physical layer connectivity problem?

Accepted Answer

ge-0/0/1. Interface ge-0/0/1 shows 'Physical link is Down' in the output, which directly indicates a physical layer connectivity problem. The 'Device present' field is also 'No', confirming that no transceiver or cable is detected, which is a Layer 1 issue.

Answer

ge-0/0/2

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ge-0/0/0

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ge-0/0/3

Question 12

An engineer needs to check the current system uptime on a Juniper device running Junos OS. Which command should they use?

Accepted Answer

show system uptime. The correct command to check current system uptime on a Juniper device running Junos OS is 'show system uptime'. This command displays the time since the system was last booted, as well as the current time and the time since the routing protocol process (rpd) started. It is the standard operational command for this specific metric.

Answer

show system status

Answer

show system health

Answer

show system resources

Question 13

A network administrator wants to view the current configuration that is actively running on a Juniper device. Which operational mode command should be used?

Accepted Answer

show configuration. In Junos OS, the operational mode command 'show configuration' displays the active, committed configuration currently running on the device. Unlike Cisco IOS, Junos does not use a separate 'running-config'; instead, the configuration is stored as a single candidate configuration that becomes active only after a 'commit' operation. Thus, 'show configuration' is the correct command to view the active configuration.

Answer

show running-config

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show active-config

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show current-config

Question 14

A junior administrator wants to view only the operational state of interface ge-0/0/1, including its link status and protocol state. Which command should they use?

Accepted Answer

show interfaces ge-0/0/1 terse. The 'show interfaces ge-0/0/1 terse' command displays a concise operational state of the interface, including link status (up/down) and protocol state (up/down) without configuration details. This is the standard Junos command for quickly verifying the operational status of a specific interface.

Answer

show interface ge-0/0/1

Answer

show configuration interfaces ge-0/0/1

Answer

show interfaces ge-0/0/1 extensive

Question 15

A network administrator is troubleshooting a routing issue and wants to view the routing table for a specific routing instance called 'VPN-A'. Which command should they use?

Accepted Answer

show route table VPN-A. The correct command to view the routing table for a specific routing instance in Junos is 'show route table VPN-A'. This command displays the routes associated with the routing instance named 'VPN-A', which is essential for troubleshooting routing issues within that instance. The 'show route' command is the standard way to view routing tables, and specifying the 'table' keyword followed by the instance name targets the correct routing table.

Answer

show routing-table VPN-A

Answer

show route instance VPN-A

Answer

show routing instance VPN-A route