JN0-106 Junos Configuration Basics Practice Test 5 — 15 Questions

Question 1

An administrator wants to view the differences between the current candidate configuration and the last committed configuration. Which command displays this?

Accepted Answer

show | compare. The 'show | compare' command displays the differences between the candidate and the active (committed) configuration.

Answer

show configuration

Answer

commit check

Answer

rollback ?

Question 2

Which TWO statements are true about the 'commit' operation in Junos?

Accepted Answer

The commit command validates the configuration syntax before applying it.. The 'commit' command in Junos performs a full syntax and consistency validation of the candidate configuration before applying it. If any errors are detected, the commit is aborted and the candidate configuration remains unchanged, ensuring the active configuration is never corrupted.

Answer

The commit command automatically saves the configuration to a file on the hard disk.

Answer

After a commit, the candidate configuration is replaced with the active configuration.

Answer

A successful commit overwrites the rollback configurations.

Question 3

Which TWO of the following are valid methods to load a configuration file into a Junos device?

Accepted Answer

load override. Options A and B are correct because 'load override' replaces the entire candidate configuration with the contents of the specified configuration file, and 'load merge' combines the configuration file with the current candidate configuration. Both are standard Junos CLI commands. Note that 'load set' and 'load replace' are also valid methods for loading configuration, but the question requires selecting exactly two correct answers, and only A and B are listed as correct in this context.

Answer

import configuration

Answer

load replace

Answer

load set

Question 4

Which THREE of the following are characteristics of configuration groups in Junos?

Accepted Answer

The 'apply-groups' statement is used to specify which group(s) should be inherited.. The 'apply-groups' statement is the Junos mechanism used to inherit configuration from a named configuration group. When you define a group under the 'groups' hierarchy, you then use 'apply-groups <group-name>' at the desired hierarchy level to pull that group's configuration into that location. This allows for modular and reusable configuration blocks.

Answer

A maximum of 10 groups can be applied to a single configuration statement.

Answer

Configuration groups do not allow individual statements within the group to be overridden in the main configuration.

Question 5

Scenario: Your company has a Juniper SRX300 firewall used as a branch gateway. It runs Junos 15.1X49. The firewall has multiple security policies, NAT rules, and VPN tunnels. Recently, you added a new security policy to allow traffic from the internal network to a specific public server. After committing, you notice that the firewall is logging repeated denials for traffic that should be matched by the new policy. The policy appears correctly configured in the candidate configuration. You want to verify that the policy is actually active and check for any hidden rules that might be causing the issue. Which of the following is the most effective first step to troubleshoot this problem?

Accepted Answer

Run 'show security policies detail' and examine the policy order to see if a previous policy is denying the traffic.. The most common cause of traffic being denied despite a seemingly correct new policy is that a preceding policy in the security policy order matches the traffic and denies it before the new policy is evaluated. Junos security policies are evaluated in sequential order from top to bottom, and the first matching policy is applied. Running 'show security policies detail' displays the active configured policy order, allowing you to see if an earlier policy is intercepting the traffic. Note: default policies are not shown with this command; use 'show security policies default' for that.

Answer

Roll back to the previous configuration to ensure the device is in a known state.

Answer

Run 'show configuration | display set | match policy' to verify the policy is present.

Answer

Check the firewall logs with 'show log messages | match deny' to see which policy is denying.

Question 6

An engineer has modified the configuration and wants to apply changes but also wants to verify that the changes are syntactically correct before committing. What command should the engineer use?

Accepted Answer

commit check. The `commit check` command validates the candidate configuration for syntax errors without activating it. This allows the engineer to verify that the changes are syntactically correct before committing, ensuring the configuration is valid and reducing the risk of committing a broken configuration.

Answer

rollback

Answer

commit confirmed

Answer

commit

Question 7

A network administrator wants to configure a user account for a junior engineer. The junior engineer should only be able to view configuration and use operational commands, but not modify anything. Additionally, the junior engineer should be required to authenticate using a local password. Which configuration accomplishes this?

Accepted Answer

set system login user junior class read-only authentication plain-text-password. The 'read-only' class in Junos provides exactly the required permissions: the ability to view configuration and execute operational commands without any modification capabilities. The 'authentication plain-text-password' directive configures local password authentication, which meets the requirement for the junior engineer to authenticate using a local password.

Answer

set system login user junior class operator authentication plain-text-password

Answer

set system login user junior class super-user authentication plain-text-password

Answer

set system login user junior class read-only authentication ssh-rsa

Question 8

Which TWO statements are true about the Junos configuration hierarchy?

Accepted Answer

The configuration is divided into a hierarchical tree.. The Junos configuration is organized as a hierarchical tree structure, where configuration statements are grouped under various hierarchy levels (e.g., 'system', 'interfaces', 'protocols'). Each statement in this tree is terminated by a semicolon, which is a fundamental syntax rule inherited from the Junos OS CLI. This hierarchical model allows for modular, structured configuration management.

Answer

Configuration is organized into two main hierarchies: system and interfaces.

Answer

Configuration must be entered in a specific order.

Answer

It is a flat structure with no grouping.

Question 9

Which THREE of the following are valid commit options in Junos?

Accepted Answer

commit synchronize. 'commit synchronize' is a valid Junos commit option used on a dual Routing Engine (RE) system to apply the configuration changes to both REs simultaneously, ensuring configuration consistency across the chassis. This command is essential for high-availability setups where both REs must share the same active configuration.

Answer

commit full

Answer

commit no-sync

Question 10

You are a junior network engineer tasked with configuring a Juniper device for the first time. The device has just been powered on and you have console access. The device boots normally and shows the login prompt. There is no root password configured, but when you try to log in as root, you are prompted for a password. You do not have any previous configuration access. What should you do to gain access and begin configuring the device?

Accepted Answer

Press the space bar during boot, then type 'boot -s' at the loader prompt.. When a Juniper device has no root password set, the default behavior is to require a password at the login prompt, even if none was configured. To bypass this, you must interrupt the normal boot process by pressing the space bar during the boot sequence, then at the loader prompt type 'boot -s' to boot into single-user mode. Single-user mode grants root access without a password, allowing you to set a root password and proceed with configuration.

Answer

Contact support to obtain a password reset.

Answer

Use the default login root with no password by pressing Enter.

Answer

Press Ctrl+C during boot to enter recovery mode.

Question 11

A Juniper router experiences a power outage. After power is restored, the router fails to boot completely and stops at the loader (U-Boot) prompt. You have console access. Before the outage, you had saved a rescue configuration. How can you load the rescue configuration to recover the system?

Accepted Answer

Type 'boot rescue' at the loader prompt.. At the U-Boot loader prompt, the 'boot rescue' command instructs the router to boot using the rescue configuration stored in the /config directory. The rescue configuration is a known-good configuration that can be saved via 'request system configuration rescue save' and is loaded directly by the boot loader when the normal boot process fails.

Answer

Type 'load rescue' at the loader prompt.

Answer

Power cycle with a pin in the reset hole.

Answer

Type 'boot -s' to enter single-user mode, then load rescue.

Question 12

An engineer is designing a network and needs to ensure that management traffic (SSH, SNMP) is always permitted, even if an interface firewall filter is applied. Which Juniper best practice should be followed?

Accepted Answer

Apply a firewall filter on the loopback interface (lo0) to protect the device. Applying a firewall filter to the loopback interface (lo0) is the Juniper best practice for protecting management traffic because the loopback interface is the logical termination point for all control plane traffic, including SSH and SNMP. This ensures that management traffic is always permitted regardless of which physical interface it arrives on, while still allowing interface-specific filters to be applied for data plane traffic without risk of blocking management access.

Answer

Use a firewall filter that permits all management traffic at the top of the list on each interface

Answer

Apply a firewall filter to the management interface (fxp0)

Answer

Disable the firewall filter on all interfaces

Question 13

Which THREE statements about the 'commit' command are correct?

Accepted Answer

The 'commit check' command validates the syntax of the candidate configuration.. The 'commit check' command validates the syntax and semantics of the candidate configuration without activating it. This allows an administrator to verify that the configuration is valid before committing, preventing potential errors from being applied to the active configuration.

Answer

The 'commit full' command activates the configuration without performing any validation.

Answer

The 'commit' command can only be issued when no other users are in configuration mode.

Question 14

A company has a Juniper MX router acting as a BGP route reflector. The router has two routing instances: 'internet' and 'management'. The 'internet' instance uses a firewall filter to block traffic to the router's loopback address from external sources. After a recent configuration change, the engineer notices that SSH access to the router's loopback IP (10.0.0.1) from the internal management network (192.168.0.0/16) is being dropped. The firewall filter for the loopback interface in the 'internet' instance is correctly configured to allow traffic from 192.168.0.0/16. The management instance has no firewall filter applied. The engineer suspects that the issue is related to how the routing instances interact with the loopback interface. Which of the following is the most likely cause and solution?

Accepted Answer

The firewall filter applied to the loopback interface is shared across all routing instances; use a separate interface for management traffic or apply the filter only to the 'internet' instance's logical system.. In Junos, firewall filters applied to the loopback interface (lo0) are shared across all routing instances by default because the loopback is a single physical interface. Even though the filter is configured in the 'internet' instance, it affects traffic destined to the loopback IP from any instance, including the 'management' instance. To isolate management traffic, you must either use a separate physical interface or apply the filter only to the 'internet' instance's logical system (e.g., using a firewall filter with a routing-instance match condition).

Answer

The management instance needs a firewall filter that allows SSH; add a filter to the management instance's loopback.

Answer

The firewall filter in the 'internet' instance incorrectly blocks SSH; modify the filter to allow SSH from any source.

Answer

The BGP configuration is causing the loopback to be unreachable; disable BGP on the management instance.

Question 15

Which TWO statements about configuration groups in Junos are correct? (Choose two.)

Accepted Answer

Configuration groups are defined under the [edit groups] hierarchy.. Configuration groups in Junos are defined under the [edit groups] hierarchy. This allows you to create reusable configuration snippets that can be applied to multiple parts of the configuration, reducing duplication and simplifying management.

Answer

Configuration groups are stored in separate files that are imported using the 'file' statement.

Answer

The 'replace' tag is used to reference a configuration group.

Answer

Configuration groups are applied only at the [edit interfaces] hierarchy level.