JN0-106 User Interfaces — 50 Questions

Question 1

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 2

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 3

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 4

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 5

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 6

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 7

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 8

You are a network engineer for a company that has just deployed a Juniper SRX firewall in a branch office. The device has multiple interfaces: ge-0/0/0 connected to the internet, ge-0/0/1 connected to the internal LAN (192.168.1.0/24), and ge-0/0/2 connected to a DMZ (10.0.0.0/24). After initial configuration, you attempt to ping from the SRX to a server on the internet (8.8.8.8) but receive no response. You also notice that internal users can access the internet. You have verified the routing table shows a default route via ge-0/0/0. The security policies appear correct. You suspect the issue is related to interface configuration. What is the most likely cause and the correct course of action?

Accepted Answer

The interface ge-0/0/0 is missing the 'host-inbound-traffic' configuration under its security zone; you should add the appropriate system services under the zone.. The SRX can ping internal hosts but not the internet because the interface ge-0/0/0 is in the untrust zone, which by default blocks all inbound traffic, including pings originated from the device itself. The 'host-inbound-traffic' configuration under the security zone allows system services such as ping, SSH, and SNMP to be received on that interface. Without it, even though the routing table and security policies are correct, the SRX will drop its own outbound ICMP echo requests before they can be sent, or drop the replies if they are treated as inbound traffic.

Answer

The security policy from the trust zone to the untrust zone is blocking traffic; you should create a policy allowing all traffic from the SRX itself.

Answer

The interface ge-0/0/0 has an incorrect MAC address; you should clear the ARP cache.

Answer

The default route is missing or incorrect; you should add a default route via the internet gateway IP.

Question 9

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 10

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 11

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 12

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 13

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

Question 14

Match each Junos interface type to its typical use.

Accepted Answer

ge: used for LAN access. Junos interface type abbreviations indicate speed and purpose: ge (Gigabit Ethernet) for LAN access, xe (10 Gigabit Ethernet) for high-speed uplinks, lo (loopback) for router ID and management, and et (40/100 Gigabit Ethernet) for data center interconnects. Common confusions include associating ge with uplinks or lo with physical interconnections.

Answer

ge: used for high-speed uplinks

Answer

lo: used for data center interconnection

Question 15

A network administrator wants to quickly review only the parts of the Junos configuration that differ from the factory defaults, to identify custom settings. Which command is most appropriate?

Accepted Answer

show configuration | display omit. The 'display omit' pipe modifier filters out configuration statements that match the factory-default values, showing only the lines that differ from the defaults. This allows the administrator to quickly review custom settings without manually comparing against a baseline.

Answer

show configuration | no-more

Answer

show configuration

Answer

show | compare

Question 16

A junior admin wants to see all commands available in operational mode that start with 'show'. What keystrokes should they use?

Accepted Answer

show ?. In Junos operational mode, typing 'show ?' and pressing Enter (or just 'show ?' without Enter) displays all commands that start with 'show'. The question mark (?) is the context-sensitive help key that lists available completions for the current partial command. Pressing Enter after 'show ?' is optional but acceptable; the key behavior is the space followed by ?.

Answer

show ? + Enter

Answer

show + ?

Answer

show <Tab>

Question 17

An engineer is configuring a firewall filter and wants to verify the syntax of the configuration before committing. Which command should be used?

Accepted Answer

commit check. The 'commit check' command validates the syntax and configuration semantics of the candidate configuration without activating it. This allows the engineer to verify that the firewall filter configuration is correct before committing, preventing potential service disruption from a faulty commit.

Answer

validate

Answer

show | display inheritance

Answer

commit confirmed

Question 18

A network operator is using the 'monitor traffic' command but wants to stop after capturing 100 packets. Which option should be added?

Accepted Answer

limit 100. The 'monitor traffic' command in Junos captures packets for analysis. To stop the capture after a specific number of packets, the correct option is 'limit 100', which instructs the command to terminate after processing 100 packets. This is a Junos-specific parameter for controlling the capture duration.

Answer

size 100

Answer

packets 100

Answer

count 100

Question 19

Which THREE statements about the Junos CLI help system are correct? (Choose three.)

Accepted Answer

Pressing completes the current keyword if unique.. Option A is correct because in the Junos CLI, pressing performs keyword completion: if the typed string uniquely matches a command or keyword, the CLI completes it automatically, and if it is ambiguous it does nothing (or beeps) rather than guessing. Option B is correct because typing ? after a partial command displays the list of available completions for that keyword or command context, which is the standard Junos context-sensitive help mechanism. Option C is correct because the 'help' command (for example, 'help topic' or 'help reference') opens the Junos documentation system and provides detailed reference material on specific topics, commands, and statements. Option D is not correct because in the Junos CLI recalls the previous command from the command history, whereas clearing the command line is done with or . Option E is not correct because pressing ? at the beginning of a line shows only the commands available at the current hierarchy level, not all commands regardless of level; to see commands at another level you must navigate to that hierarchy first.

Answer

Pressing <Ctrl+P> clears the command line.

Answer

Pressing ? at the beginning of a line shows all commands regardless of the current hierarchy level.

Question 20

An engineer needs to check if a junos configuration file is syntactically correct before applying it. Which command should be used?

Accepted Answer

commit check. The 'commit check' command validates the syntax and semantics of the candidate configuration without applying it. If errors are found, they are reported, and the configuration is not committed. This allows the engineer to verify correctness before making the change active.

Answer

load check

Answer

check commit

Answer

validate