JNCIA-JUNOS Timed Practice Test 5 — 10 Questions

Question 1

Which THREE commands are valid Junos operational mode commands for monitoring network diagnostics? (Choose three.)

Accepted Answer

traceroute. Option A is correct because the 'traceroute' command in Junos operational mode sends a series of UDP packets with increasing TTL values to discover the path a packet takes to a destination, which is a standard network diagnostic tool. It is a valid operational mode command used for monitoring network connectivity and path analysis.

Answer

show configuration

Answer

request system reboot

Question 2

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.. Option B is correct because 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 3

During troubleshooting, an engineer needs to view real-time logging messages on a Junos device. Which command should be used?

Accepted Answer

monitor start messages. The 'monitor start messages' command enables real-time, tail-like display of the /var/log/messages log file on a Junos device, allowing the engineer to view new log entries as they are generated. This is the correct command for live troubleshooting because it continuously updates the terminal with incoming syslog messages, unlike static file viewing commands.

Answer

file show /var/log/messages

Answer

show log messages

Answer

traceoptions

Question 4

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 5

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 6

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. Option A is correct because 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

Answer

show route forwarding-table

Answer

show route protocol bgp

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

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 9

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

Accepted Answer

The pipe (|) can be used to filter command output.. Option A is correct because 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 10

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

Accepted Answer

exit configuration-mode. Option A is correct because '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