JN0-106 User Interfaces Practice Test 6 — 15 Questions

Question 1

A network engineer is in configuration mode and wants to see the configuration in a format that can be directly pasted into another router to reproduce the configuration. Which output modifier should they use?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

| display set. The '| display set' output modifier converts the current Junos configuration into a series of 'set' commands. This format is directly pasteable into another router's CLI to reproduce the exact configuration, making it ideal for configuration migration or backup restoration.

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| display inheritance

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| display xml

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| count

Question 2

A user wants to see all available commands starting with 'show'. Which key should they press after typing 'show'?

Accepted Answer

?. In the Junos CLI, pressing the '?' key after typing a partial command like 'show' displays a list of all available commands or options that start with that string. This is the standard context-sensitive help feature in Junos, which is distinct from other CLI behaviors.

Answer

Space

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Tab

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Ctrl-P

Question 3

Which THREE CLI features are available in Junos OS to assist with command entry?

Accepted Answer

? (question mark) for context-sensitive help.. Option A is correct because in Junos OS CLI, typing ? at any point displays context-sensitive help listing valid commands, keywords, or options available at that position. Option C is correct because the Up arrow key scrolls backward through the command history buffer, allowing the user to recall and re-execute previously entered commands. Option E is correct because the Tab key performs command and option completion, automatically finishing a partially typed command or keyword when the entry is unambiguous. Option B is incorrect because Ctrl+R is not a Junos OS command-recall feature; command history is navigated with the Up/Down arrow keys or the show cli history command. Option D is incorrect because Ctrl+Z is not an undo function in Junos OS; it is not a supported command-entry aid in the CLI.

Answer

Ctrl+R to repeat the last command.

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Ctrl+Z to undo the last command.

Question 4

Refer to the exhibit. What is the purpose of the 'unit 0' statement?

Accepted Answer

Defines a logical interface.. In Junos, the 'unit 0' statement is used to define a logical interface (also known as a subinterface) under a physical interface. Every physical interface must have at least one logical unit, and unit 0 is the default logical interface that carries Layer 3 configuration such as IP addresses. This is fundamental to Junos architecture, where all protocol configurations are applied at the logical unit level, not the physical interface level.

Answer

Enables IPv6.

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Sets the MTU.

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Defines a physical interface.

Question 5

Refer to the exhibit. What does this output indicate?

Accepted Answer

The candidate configuration differs from the active configuration.. The output shows the 'show | compare' command, which displays the differences between the candidate configuration and the active (committed) configuration. The presence of lines prefixed with '+' (additions) and '-' (deletions) indicates that the candidate configuration is not identical to the active configuration, confirming that they differ.

Answer

There is a syntax error.

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The commit succeeded.

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The configuration is identical.

Question 6

Refer to the exhibit. What does this command accomplish?

Accepted Answer

Displays syslog messages containing the word 'error'.. The command shown filters the output of the system log file to display only lines containing the substring 'error'. This allows the administrator to quickly see log entries related to errors, rather than viewing all messages or a dedicated error log file.

Answer

Displays help for syslog messages that include 'error'.

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Displays all syslog messages.

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Displays the error log file.

Question 7

A junior engineer uses 'set system host-name R1' in configuration mode and exits without committing. After a reboot, the hostname reverts to the original. What step did the engineer miss?

Accepted Answer

They must commit the configuration with 'commit'.. In Junos OS, configuration changes made in configuration mode are stored in a candidate configuration and do not take effect until explicitly committed using the 'commit' command. Rebooting without committing discards all uncommitted changes, causing the hostname to revert to its original value. Option D is correct because the engineer must issue 'commit' to activate the new hostname permanently.

Answer

They must use 'run set system host-name' instead.

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They must save the configuration to a file.

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They must reboot after setting the hostname.

Question 8

While in configuration mode, an engineer types 'show' and sees a different output than when typing 'run show configuration'. Why?

Accepted Answer

'show' shows the candidate configuration; 'run show configuration' shows the active configuration.. In Junos, when you are in configuration mode and type 'show', it displays the candidate configuration (the changes you have made but not yet committed). The command 'run show configuration' executes the operational-mode command 'show configuration' from within configuration mode, which displays the active (committed) configuration. Therefore, option B correctly identifies that 'show' shows the candidate configuration and 'run show configuration' shows the active configuration.

Answer

'show' shows the active configuration; 'run show configuration' shows the candidate.

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Both commands produce identical output.

Answer

'run show configuration' is not allowed from configuration mode.

Question 9

A network engineer needs to revert to the configuration that was committed two commits ago. Which rollback number should they use?

Accepted Answer

rollback 2. The rollback command in Junos OS allows reverting to a previously committed configuration. The rollback number corresponds to the number of commits ago, starting with rollback 0 for the most recent commit, rollback 1 for the commit before that, and so on. Therefore, to revert to the configuration committed two commits ago, the correct rollback number is 2.

Answer

rollback 0

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rollback 1

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rollback 3

Question 10

A user wants to discard all uncommitted changes and return to the last committed configuration without exiting configuration mode. Which command should they use?

Accepted Answer

rollback 0. 'rollback 0' discards all uncommitted changes and reverts the candidate configuration to the last committed configuration, all while staying in configuration mode. In Junos, rollback 0 specifically refers to the most recently committed configuration, making it the exact command to undo uncommitted edits without exiting.

Answer

load override

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reload

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commit check

Question 11

During a maintenance window, an engineer makes critical changes and wants the configuration to automatically revert if they lose connectivity. Which command should they use before committing?

Accepted Answer

commit confirmed. 'commit confirmed', is correct because it allows the engineer to commit a configuration change with a default 10-minute rollback timer. If the engineer loses connectivity and does not confirm the commit within that period, the system automatically reverts to the previous configuration, ensuring the device remains reachable.

Answer

commit

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commit check

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commit at

Question 12

What permission bit must be included in a custom login class to allow a user to execute the ping command?

Accepted Answer

network. Network. In Junos, the 'network' permission bit controls access to network diagnostic commands such as ping, traceroute, and ssh. Without this permission, a user cannot execute these commands even if they have other permissions like view or control.

Answer

view

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control

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system

Question 13

An engineer wants to view system log messages as they are generated in real-time. Which command should they use?

Accepted Answer

monitor log messages. The 'monitor log messages' command in Junos OS provides a real-time view of system log messages as they are generated, similar to the 'tail -f' command on Unix systems. It streams new log entries to the terminal without requiring manual refresh, making it ideal for live monitoring of events.

Answer

start log messages

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request system log

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show log messages

Question 14

Which TWO statements are true about commit operations in Junos? (Choose two.)

Accepted Answer

The commit command requires the candidate configuration to be syntactically correct.. Option B is correct because the commit command validates the candidate configuration for syntax and semantic errors before merging it into the active configuration; if the candidate is not syntactically correct, the commit fails and the running configuration remains unchanged. Option C is correct because commit confirmed activates the candidate configuration on a trial basis and, if the operator does not issue a confirming commit within the default 10-minute window, Junos automatically rolls back to the previously active configuration. Option A is wrong because rollback 0 loads the last committed (active) configuration into the candidate, it does not reboot the device. Option D is wrong because commit check only validates the candidate configuration for syntax and commit-time errors without applying it to the running system. Option E is wrong because commit at schedules a configuration commit at a specified time, not a system reboot.

Answer

The rollback 0 command will cause a system reboot.

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The commit check command applies the configuration to the running system.

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The commit at command is used to schedule a system reboot.

Question 15

Which THREE pipe modifiers can be used to filter command output? (Choose three.)

Accepted Answer

count. In network CLI environments such as Junos, the pipe modifier 'count' (option B) filters command output by returning only the number of lines the preceding command produces, which is a valid way to filter/summarize output. The 'match' modifier (option D) filters output by displaying only lines that match a given regular expression, directly narrowing the returned text. The 'except' modifier (option E) filters output by excluding lines that match a specified pattern, the inverse of match, and is likewise a legitimate output filter. The unmarked options do not belong: 'no-more' (option A) is a terminal display control that disables paging, not a filter, and 'display set' (option C) is a configuration display format command, not a pipe modifier for filtering output.

Answer

no-more

Answer

display set