JN0-106 Operational Monitoring and Maintenance Practice Test 3 — 15 Questions

Question 1

A network engineer needs to verify the checksum of a downloaded Junos image before installation. Which command is used?

Accepted Answer

file checksum sha256 . The `file checksum sha256 ` command computes the SHA-256 hash of the specified file, allowing the engineer to compare it against the published checksum from Juniper Networks to verify integrity and authenticity before installation. This ensures the image has not been corrupted or tampered with during download.

Answer

compare <filename> original

Answer

request system software validate <filename>

Answer

show system software

Question 2

Which two commands can be used to display real-time interface information? (Choose two.)

Accepted Answer

monitor interface. The `monitor interface` command provides a real-time, continuously updating view of interface statistics, including traffic counters, errors, and operational status. The `monitor traffic` command captures and displays live packet headers or full packets on an interface, useful for real-time traffic analysis. Both commands are designed for live monitoring, unlike static `show` commands or administrative actions.

Answer

show log

Answer

request system reboot

Answer

show system storage

Question 3

Which three steps are part of a typical software upgrade process on a Juniper device? (Choose three.)

Accepted Answer

Issue the request system software add command. The 'request system software add' command is the standard Junos CLI command used to initiate the installation of a new software image on a Juniper device. This command triggers the process of copying the image from a specified source (e.g., a URL or local file) into the system's active software partition, preparing it for the next reboot.

Answer

Shut down all interfaces

Answer

Delete the old image before adding the new one

Question 4

Refer to the exhibit. An engineer notices that input drops are increasing. What is the most likely cause?

Accepted Answer

Buffer overflow. Input drops occur when the ingress interface's receive buffer is full and cannot accept more packets, typically due to the ingress rate exceeding the interface's ability to process or forward packets to the internal switch fabric. In Junos, this is often caused by microbursts or sustained oversubscription, not by a speed mismatch (which would show as errors or link flaps) or cable faults (which cause physical-layer errors). Buffer overflow is the correct answer because input drops directly indicate that the packet buffer has been exhausted.

Answer

Speed mismatch

Answer

Cable fault

Answer

CRC errors

Question 5

Refer to the exhibit. What is the most likely cause of the BGP session failure?

Accepted Answer

Hold timer expired due to delayed keepalives. The BGP session failure is most likely due to the hold timer expiring because keepalive messages were not received in time. In JUNOS, the default hold time is 90 seconds, and if a router does not receive a keepalive or update within that interval, it declares the peer dead and resets the session. The exhibit shows the BGP state as 'Idle' or 'Active', which is consistent with a hold timer expiry event.

Answer

The peer is unreachable

Answer

BGP configuration mismatch

Answer

Route flapping

Question 6

Refer to the exhibit. Which route will be used to forward traffic to 192.168.1.0/24?

Accepted Answer

The route via 10.0.0.2 because it has a lower metric. The route via 10.0.0.2 is selected because it has a lower metric. In Junos, when multiple routes to the same destination have the same preference (administrative distance), the route with the lower metric is preferred. The exhibit shows two OSPF routes with equal preference, so the metric determines the active route.

Answer

Neither route is valid

Answer

The route via 10.0.0.1 because it was learned later

Answer

Both routes are used for load balancing

Question 7

During a network outage, a router is unresponsive via SSH. You have console access but the console displays 'Amnesiac (ttyd0)' prompt. What is the most likely cause and recovery action?

Accepted Answer

The router lost its configuration; load the rescue configuration using 'rollback rescue-config' or 'load override /config/rescue.conf.gz' then commit. The 'Amnesiac (ttyd0)' prompt indicates the router has booted without a valid configuration file in the /config directory. This typically occurs after a 'request system zeroize' command, a failed commit that corrupted the configuration, or a storage issue that prevented the configuration from loading. The recovery action is to load a previously saved rescue configuration using 'rollback rescue' or 'load override /config/rescue.conf.gz' and then commit, which restores the router to a known working state.

Answer

The router's boot device failed; need to replace hardware

Answer

The router booted from backup media; run 'request system software add' to reinstall Junos

Answer

The router's flash memory is corrupted; perform a full reinstall via USB

Question 8

Which THREE statements are true about the commit operation on Junos?

Accepted Answer

The commit operation validates the configuration before applying.. Option A is true because commit validates the configuration before applying. Option C is true because a commit immediately activates the candidate configuration. Option E is true because commit check can validate without committing. Option B is false: the commit confirmed feature does not confirm with a time delay; it requires confirmation within a time delay to avoid rollback.

Answer

The commit operation can be confirmed with a time delay.

Answer

The commit operation always requires a reboot.

Question 9

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 10

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

Answer

show active-config

Answer

show current-config

Question 11

Which command displays the version of Junos OS currently running on the device?

Accepted Answer

show version. The 'show version' command is the standard Junos CLI command that displays the Junos OS version currently running on the device, including the software release, build date, and the type of software (e.g., Junos 22.4R2.11). It is the direct equivalent of 'show version' in Cisco IOS and is the primary command for verifying the active software image.

Answer

show system hardware

Answer

show system uptime

Answer

show system information

Question 12

A network engineer notices that the device is not accepting any configuration changes. The engineer suspects the configuration database is locked. Which command can be used to confirm if the configuration is locked and by which session?

Accepted Answer

show system configuration lock. The 'show system configuration lock' command displays information about any current configuration database locks, including the session ID, user, and time the lock was acquired. This directly confirms whether the configuration is locked and by which session, allowing the engineer to identify the blocking session.

Answer

show system rollback compare

Answer

show system commit

Answer

show system database

Question 13

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 14

An administrator needs to verify the current time and time zone configured on the Juniper device. Which command should they use?

Accepted Answer

show system clock. The correct command is 'show system clock' because it displays the current system time and time zone configured on the Juniper device. This command is specifically designed to show the local time, time zone offset, and whether daylight saving time is active, making it the precise tool for verifying time and time zone settings.

Answer

show system uptime

Answer

show system information

Answer

show system date

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