JN0-106 User Interfaces Practice Test 4 — 15 Questions

Question 1

Refer to the exhibit. An engineer sees that the interface ge-0/0/0 has 'Admin up' and 'Link up'. What does this indicate?

Accepted Answer

The interface is up and the physical link is up.. When an interface shows 'Admin up' and 'Link up', it means the interface has been administratively enabled (no 'shutdown' command applied) and the physical layer has detected a carrier signal from the connected device. In Junos, this is the normal operational state for a functioning interface, confirming that both the administrative configuration and the physical link are active.

Answer

The interface is administratively down.

Answer

The interface is a loopback interface.

Answer

The interface has an IPv6 address only.

Question 2

Refer to the exhibit. An engineer wants to revert to the configuration from January 14. Which rollback number should they use?

Accepted Answer

rollback 1. The rollback command in Junos reverts the candidate configuration to a previously committed configuration. The rollback numbers are indexed from 0 (the most recent commit) to 49 (the oldest). Since the engineer wants to revert to the configuration from January 14, and the most recent commit (rollback 0) is from January 15, rollback 1 corresponds to the January 14 configuration. Therefore, option D is correct.

Answer

load override 2

Answer

rollback 2

Answer

rollback 0

Question 3

A network administrator needs to view the current configuration but is only interested in the interfaces section. Which CLI command should they use?

Accepted Answer

show configuration interfaces. The 'show configuration interfaces' command displays only the interfaces hierarchy from the active candidate configuration. This command directly filters the configuration output to the interfaces stanza, allowing the administrator to view interface-specific settings without extraneous configuration data.

Answer

show configuration | display set

Answer

show interfaces

Answer

show configuration | match interfaces

Question 4

An engineer is troubleshooting a connectivity issue and wants to see real-time interface traffic statistics. Which command provides continuous updates?

Accepted Answer

monitor interface traffic. The `monitor interface traffic` command in Junos OS provides a real-time, continuously updating display of interface traffic statistics, making it the correct choice for live monitoring. Unlike static commands that show a single snapshot, this command refreshes the output at a default interval (typically 1 second) until the user interrupts it with Ctrl+C.

Answer

show interface statistics

Answer

monitor start messages

Answer

show interfaces extensive

Question 5

A junior admin tries to commit a configuration but receives a 'commit error: syntax error' message. They suspect a missing closing brace. Which CLI command helps identify the exact line with the error?

Accepted Answer

commit check. The 'commit check' command validates the candidate configuration for syntax errors without committing it. When a syntax error like a missing closing brace is present, commit check outputs the exact line number and file where the error occurs, allowing the admin to locate and fix the issue before attempting a commit again.

Answer

rollback 0

Answer

load merge

Answer

show configuration

Question 6

A technician wants to view the system log messages in real time. Which command should they use?

Accepted Answer

monitor start messages. The 'monitor start messages' command is used in Junos OS to display system log messages in real time as they are generated. This is the correct command for live monitoring of system events, similar to 'tail -f' on Unix systems.

Answer

show system log

Answer

start shell

Answer

show log messages

Question 7

An operator needs to copy the running configuration to a remote FTP server for backup. Which command accomplishes this?

Accepted Answer

file copy /config/juniper.conf.gz ftp://user:pass@server/path. The `file copy` command in Junos is the standard method for transferring files to or from the device, and it supports FTP as a source or destination. The syntax `file copy /config/juniper.conf.gz ftp://user:pass@server/path` correctly specifies the local file path and the remote FTP URL, including credentials and destination path.

Answer

scp /config/juniper.conf.gz user@server:/path

Answer

copy configuration to ftp://user:pass@server/path

Answer

ftp put /config/juniper.conf.gz

Question 8

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?

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.

Answer

| display inheritance

Answer

| display xml

Answer

| count

Question 9

During a maintenance window, a network engineer is about to commit changes but wants to ensure no active sessions are disrupted. Which command should they run first?

Accepted Answer

commit confirmed. The 'commit confirmed' command allows the engineer to apply changes with a default 10-minute rollback timer. If the commit is not confirmed within that window, Junos automatically reverts to the previous configuration, ensuring that any disruption caused by the changes is temporary and active sessions are not permanently affected.

Answer

commit check

Answer

commit synchronize

Answer

commit at

Question 10

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

Answer

Tab

Answer

Ctrl-P

Question 11

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

Accepted Answer

It applies the candidate configuration to the active configuration.. The 'commit' operation in Junos OS applies the candidate configuration to the active configuration, making the changes effective immediately. This is the fundamental purpose of the commit command, which activates the pending configuration changes stored in the candidate configuration database.

Answer

It can be rolled back using the 'rollback 0' command.

Answer

It automatically reboots the device if system changes are made.

Answer

It requires the configuration to be validated with 'commit check' first.

Question 12

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

Accepted Answer

? (question mark) for context-sensitive help.. The question mark (?) provides context-sensitive help in Junos OS, displaying available commands, options, and syntax at any point in the CLI. This is a fundamental feature for command discovery and verification, especially when the exact command syntax is not known.

Answer

Ctrl+R to repeat the last command.

Answer

Ctrl+Z to undo the last command.

Question 13

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.

Answer

The commit succeeded.

Answer

The configuration is identical.

Question 14

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.

Answer

They must save the configuration to a file.

Answer

They must reboot after setting the hostname.

Question 15

An engineer wants to see the differences between the active configuration and the candidate configuration. Which command should they use?

Accepted Answer

'show configuration | compare'. Both 'show | compare' (in configuration mode) and 'show configuration | compare' (in operational mode) display the differences between the active and candidate configurations. Option D is valid in configuration mode, while option B is valid in operational mode. The question does not specify the mode, so both are correct.

Answer

'show configuration | display set'

Answer

'run show configuration | compare'