JN0-106 User Interfaces — Timed 30 Questions

Question 1

A network engineer needs to commit a configuration change but wants to ensure the change can be easily reverted if it causes issues. Which approach should the engineer take?

Accepted Answer

Use the 'commit confirmed' command with a timeout.. The 'commit confirmed' command allows the engineer to commit a configuration change with a default timeout of 10 minutes (configurable). If the change causes issues and the engineer does not confirm the commit within the timeout period, Junos automatically reverts to the previous active configuration, providing a safe rollback mechanism.

Answer

Use the 'commit and-quit' command to apply changes.

Answer

Use the 'commit check' command before committing.

Answer

Use the 'rollback 0' command after committing.

Question 2

An administrator wants to view the current operational status of interface ge-0/0/1 on a Junos device. Which command displays this information?

Accepted Answer

show interfaces terse ge-0/0/1. The 'show interfaces terse ge-0/0/1' command displays a concise, one-line summary of the operational status of the specified interface, including its administrative and link state, protocol status, and configured IP addresses. This is the correct command for viewing the current operational status because 'terse' filters the output to show only the essential operational details without configuration data.

Answer

show configuration interfaces ge-0/0/1

Answer

monitor interface ge-0/0/1

Answer

show interface ge-0/0/1

Question 3

A junior engineer is troubleshooting a routing issue and wants to see the route table for IPv4 unicast routes. Which command will display this information?

Accepted Answer

show route table inet.0. The command 'show route table inet.0' displays the IPv4 unicast route table in Junos. The inet.0 table is the default routing table for IPv4 unicast routes, containing all active routes learned via various protocols (e.g., OSPF, BGP, static). This command is the standard way to view the IPv4 unicast routing information base (RIB) on Juniper devices.

Answer

show route table inet6.0

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show route forwarding-table

Answer

show route protocol bgp

Question 4

An engineer needs to apply a configuration change to the device, but only if the configuration is syntactically correct. Which command should be used before committing?

Accepted Answer

commit check. The 'commit check' command validates the candidate configuration for syntax errors without applying it, making it the correct choice when the engineer only wants to verify syntactic correctness before committing. Unlike 'commit', which applies changes immediately, 'commit check' performs the same validation as a commit but stops short of activating the configuration.

Answer

commit

Answer

commit confirmed

Answer

show | compare

Question 5

An administrator wants to navigate to the configuration mode to make changes to the device. Which command should be used?

Accepted Answer

configure. The correct command to enter configuration mode on a Juniper device is 'configure'. This command transitions the CLI from operational mode to configuration mode, allowing the administrator to make changes to the device's configuration. In JUNOS, the CLI has two distinct modes: operational mode (for monitoring and troubleshooting) and configuration mode (for modifying the active or candidate configuration).

Answer

set

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edit

Answer

cli

Question 6

A network engineer needs to revert to the configuration that was active before the last commit. Which command accomplishes this?

Accepted Answer

rollback 1. The 'rollback 1' command reverts the active configuration to the configuration that was committed immediately before the most recent commit. Junos maintains up to 50 previous committed configurations (rollback 0 being the current active configuration, rollback 1 the previous, and so on). This command is the correct way to undo the last commit without manually editing the configuration.

Answer

rollback 0

Answer

load override

Answer

revert

Question 7

An administrator wants to see the differences between the candidate configuration and the active configuration. Which command should be used?

Accepted Answer

show | compare. The 'show | compare' command displays the differences between the candidate configuration and the active (committed) configuration. This is the standard Junos method for reviewing uncommitted changes before committing them, as it outputs a diff-style output showing lines added, deleted, or modified.

Answer

show | display set

Answer

run show configuration

Answer

show configuration

Question 8

Which TWO statements are true regarding the Junos CLI? (Choose two.)

Accepted Answer

The pipe (|) can be used to filter command output.. The pipe (|) in the Junos CLI is used to filter command output, allowing you to apply modifiers like 'match', 'except', 'count', or 'display set' to refine the displayed information. This is a fundamental feature for efficiently managing large amounts of operational or configuration data.

Answer

The 'edit' command is used in operational mode to navigate the hierarchy.

Answer

The 'set' command is used in operational mode to set parameters.

Answer

The 'rollback 0' command discards the candidate configuration.

Question 9

Which THREE are valid methods to exit configuration mode in Junos? (Choose three.)

Accepted Answer

exit configuration-mode. 'exit configuration-mode' is a valid operational mode command that explicitly exits from configuration mode back to operational mode. This command is used when you are at the top of the configuration hierarchy and want to leave the configuration CLI session.

Answer

commit check

Answer

quit

Question 10

Which TWO commands can be used to view the current operational state of an interface? (Choose two.)

Accepted Answer

show interfaces extensive. The 'show interfaces extensive' command displays detailed operational state information, including current status, errors, and statistics. The 'show interfaces terse' command provides a concise operational view showing interface names, administrative status, link status, and protocol families. Both commands query the current operational state of interfaces from the Junos OS kernel.

Answer

show log

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show configuration interfaces

Answer

show route

Question 11

Refer to the exhibit. Based on the output, what is the operational status of interface ge-0/0/0?

Accepted Answer

The interface is administratively up and the link is up.. The output shows 'Physical link is Up' and 'Administratively Up', confirming that the interface is both enabled and receiving a carrier signal. In JUNOS, the 'show interfaces terse' command displays 'up' for the administrative status and 'up' for the link status when both conditions are met.

Answer

The interface is up but the link is down.

Answer

The interface has no IP address configured.

Answer

The interface is administratively down.

Question 12

Refer to the exhibit. An engineer runs the command but sees no output. What is the most likely reason?

Accepted Answer

The interface ge-0/0/0 is not configured.. The command 'show configuration | display set' outputs the configuration in a set-based format. If there is no output, it means the configuration is empty or the specified interface does not exist. In this case, the interface ge-0/0/0 is not configured, so the filter 'display set' returns no lines for that interface. Option B is correct because an unconfigured interface yields no configuration output.

Answer

The pipe (|) is not supported with 'display set'.

Answer

The interface name is misspelled.

Answer

The command syntax is incorrect.

Question 13

You are managing a Juniper EX4300 switch that serves as a Layer 3 access switch for a campus network. The switch has multiple VLANs configured with IRB interfaces. Users in VLAN 10 report that they cannot reach the default gateway (IRB.10) even though other VLANs are working fine. You check the configuration and see that interface irb.10 is configured with an IP address. You also verify that the VLAN is associated with the correct access ports. However, when you ping the IRB.10 address from the switch itself, it fails. You suspect that the issue might be that the IRB interface is not 'up'. Which command would you use to quickly verify the operational status of the IRB interface?

Accepted Answer

show interfaces terse irb.10. `show interfaces terse irb.10` displays the operational status (up/down) of the IRB interface along with its configured IP address. Since the issue is that the IRB interface may not be 'up', this command quickly confirms whether the interface is operationally active, which is essential for Layer 3 forwarding.

Answer

show ethernet-switching table

Answer

show configuration interfaces irb.10

Answer

show vlan

Question 14

Which TWO statements correctly describe the behavior of the 'commit confirmed' command in Junos?

Accepted Answer

The confirmation timeout can be modified by specifying a number of minutes.. The `commit confirmed` command in Junos accepts an optional numeric argument (in minutes) to override the default confirmation timeout. For example, `commit confirmed 10` sets a 10-minute window during which the administrator must issue a `commit` to make the changes permanent; otherwise, the system automatically rolls back to the previous active configuration.

Answer

The default confirmation timeout is 5 minutes.

Answer

It requires a reboot to revert to the previous configuration.

Answer

It stages the configuration in the candidate configuration but does not apply it until confirmed.

Question 15

Refer to the exhibit. Which interface has an operational issue that prevents it from passing traffic?

Accepted Answer

ge-0/0/1. Interface ge-0/0/1 shows 'Link: DOWN' in the output, indicating a physical layer issue such as a disconnected cable, faulty transceiver, or administrative shutdown. A down link prevents any traffic from being forwarded over that interface, regardless of its protocol configuration.

Answer

lo0

Answer

ge-0/0/2

Answer

ge-0/0/0

Question 16

Which TWO statements correctly describe the behavior of the Junos CLI operational mode?

Accepted Answer

Commands such as show and ping are available.. Junos CLI operational mode provides commands for monitoring, troubleshooting, and verifying the device state, such as 'show' for displaying configuration and operational data, and 'ping' for network connectivity tests. These commands do not alter the active configuration, which is the defining characteristic of operational mode.

Answer

Command options are enclosed in curly braces { }.

Answer

Commands must be entered in full; abbreviation is not allowed.

Answer

You can commit configuration changes directly.

Question 17

Refer to the exhibit. An engineer configures a new IPv6 address on ge-0/0/0 unit 0 by entering the following commands in configuration mode:

set interfaces ge-0/0/0 unit 0 family inet6 address 2001:db8::2/64
commit

After the commit, the engineer runs 'show interfaces terse ge-0/0/0' and sees only the two original addresses. What is the most likely cause?

Accepted Answer

The engineer did not enter configuration mode before running the 'set' command.. The engineer likely ran the 'set' command from operational mode (e.g., at the '>' prompt) rather than from configuration mode (e.g., at the '#' prompt). In Junos, 'set' commands only take effect when entered in configuration mode; if entered in operational mode, they are silently ignored or produce an error, and the configuration is not modified. Since the engineer saw no new address after commit, the 'set' command was never applied to the candidate configuration.

Answer

The engineer used 'commit' instead of 'commit confirmed'.

Answer

Junos only allows one IPv6 address per interface.

Answer

The 'set' command requires the 'add' keyword to add a second address.

Question 18

Arrange the steps to configure a static route in Junos OS in the correct order.

Accepted Answer

Enter configuration mode, then set the static route under routing-options static, then commit the configuration, then verify the route with show route.. Static routes are configured under 'routing-options static' in Junos. After setting the route, you must commit and verify.

Answer

Enter configuration mode, then commit the configuration, then set the static route under routing-options static, then verify the route with show route.

Answer

Set the static route under routing-options static, then enter configuration mode, then commit the configuration, then verify the route with show route.

Answer

Enter configuration mode, then set the static route under routing-options static, then verify the route with show route, then commit the configuration.

Question 19

Arrange the steps to perform a system backup (snapshot) on a Junos device.

Accepted Answer

Step 1: Connect to the device. Step 2: Enter operational mode. Step 3: Execute 'request system snapshot'. Step 4: Confirm the operation by typing 'yes'.. Snapshot creates a bootable backup of the Junos system. The steps are straightforward.

Answer

Step 1: Connect to the device. Step 2: Execute 'request system snapshot'. Step 3: Enter operational mode. Step 4: Confirm the operation.

Answer

Step 1: Execute 'request system snapshot'. Step 2: Connect to the device. Step 3: Enter operational mode. Step 4: Confirm the operation.

Answer

Step 1: Enter operational mode. Step 2: Execute 'request system snapshot'. Step 3: Confirm the operation. Step 4: Connect to the device.

Question 20

Match each Junos CLI operational mode command to its function.

Accepted Answer

show interface terse: Displays summary information about all interfaces. These are common operational mode commands used for monitoring and troubleshooting in Junos.

Answer

show interface terse: Displays detailed interface statistics

Answer

show route: Displays the configuration of routing protocols