JN0-106 Practice Test 8 — 10 Questions

Question 1

An engineer issues the 'rollback 3' command in configuration mode. What is the effect?

Accepted Answer

The candidate configuration is replaced with the configuration from three commits ago.. The 'rollback 3' command in Junos configuration mode replaces the current candidate configuration with the configuration from the third most recent commit. Junos maintains up to 50 rollback slots (numbered 0 through 49), where slot 0 is the most recent commit, slot 1 is the commit before that, and so on. Therefore, 'rollback 3' retrieves the configuration saved three commits ago, overwriting any uncommitted changes in the candidate configuration.

Answer

The candidate configuration is saved as the third rollback slot.

Answer

The active configuration is replaced with the candidate configuration.

Answer

The device reboots and loads configuration version 3.

Question 2

During troubleshooting, an engineer notices that BGP sessions are flapping. They suspect that the issue might be related to the maximum number of routes allowed. To see if the BGP import policy is rejecting routes, which operational command would provide immediate insight?

Accepted Answer

show bgp neighbor x.x.x.x. The 'show bgp neighbor x.x.x.x' command displays detailed BGP session information, including the number of received and accepted routes, as well as any prefix-limit or policy-related rejections. If the BGP import policy is rejecting routes due to exceeding the maximum allowed, this command will show the 'received prefixes' count alongside the 'accepted prefixes' count, immediately revealing if routes are being dropped. This provides direct insight into whether the flapping is caused by route limit enforcement.

Answer

show version

Answer

show interfaces terse

Answer

show route protocol bgp

Question 3

Which two commands display the IPv4 unicast routing table? (Choose two.)

Accepted Answer

show route. Option C, `show route`, is correct because on Junos devices this command displays the complete routing table, which by default is the IPv4 unicast table (inet.0), listing all learned and direct routes. Option D, `show route table inet.0`, is also correct because inet.0 is the specific routing table name for IPv4 unicast routes, so this command explicitly displays exactly that table. Option A, `show ip route`, is not a valid Junos command (it is Cisco IOS syntax), so it does not belong. Option B, `show route protocol ospf`, only filters and displays OSPF-learned routes rather than the entire IPv4 unicast routing table. Option E, `show routing`, is not a valid command and therefore cannot display the routing table.

Answer

show ip route

Answer

show route protocol ospf

Answer

show routing

Question 4

Which THREE statements correctly describe the behavior of the 'replace pattern' command in Junos configuration mode?

Accepted Answer

It can be used to change interface names or IP addresses throughout the configuration.. Option C is correct because the 'replace pattern' command performs a global find-and-replace across the candidate configuration, making it ideal for renaming interfaces or changing IP addresses everywhere they appear. Option D is correct because 'replace pattern' edits the candidate configuration, not the active configuration, so changes must still be committed to take effect. Option E is correct because the command matches text using regular expressions (e.g., 'replace pattern ge-0/0/0 with ge-0/0/1'), allowing flexible pattern-based substitutions. Option A is not correct because 'replace pattern' does not itself validate the replacement for correctness before applying; validation occurs at commit time via 'commit check' or the commit process. Option B is not correct because 'replace pattern' does not automatically commit changes; the user must explicitly issue a 'commit' command afterward.

Answer

It validates the replacement configuration for correctness before applying.

Answer

It automatically commits the changes after replacement.

Question 5

Which two commands can be used to display real-time interface information? (Choose two.)

Accepted Answer

monitor interface. Option A, `monitor interface`, is correct because it provides a real-time, continuously updating view of interface statistics such as traffic counters, errors, and link state on Juniper devices. Option B, `monitor traffic`, is correct because it captures and displays live packet-level traffic on an interface, showing real-time data as packets traverse the interface. Option C, `show log`, is incorrect because it displays stored log file contents rather than live interface information. Option D, `request system reboot`, is incorrect because it reboots the device and does not display interface data. Option E, `show system storage`, is incorrect because it reports disk and filesystem usage, not real-time interface information.

Answer

show log

Answer

request system reboot

Answer

show system storage

Question 6

Which THREE actions can be performed in operational mode on a Junos device?

Accepted Answer

Ping a remote host. In Junos, operational mode is the CLI mode entered after login (prompt user@host>), used for monitoring and controlling device state. Option B (Ping a remote host) is correct because the ping command is an operational-mode command used to test reachability to a remote host. Option D (View system logs) is correct because operational mode provides commands such as show log messages to inspect system log files. Option E (Reboot the chassis) is correct because the request system reboot command is executed from operational mode to restart the device. Options A and C are not operational-mode actions: committing configuration changes (commit) and configuring interface IP addresses (set interfaces ...) are performed in configuration mode, which is entered with the configure command.

Answer

Commit configuration changes

Answer

Configure interface IP addresses

Question 7

Which TWO statements about the rescue configuration are correct? (Choose two.)

Accepted Answer

The rescue configuration is designed to provide a method of last-resort recovery.. Option C is correct because the rescue configuration exists specifically as a last-resort recovery mechanism, allowing an administrator to return a device to a known-good configuration when the active configuration is broken or inaccessible. Option D is correct because on Junos devices the rescue configuration is created and stored by running the operational-mode command 'request system configuration rescue save', which snapshots the current candidate configuration as the rescue configuration. Option A is wrong because the rescue configuration is not saved automatically on every commit; it must be saved explicitly by the administrator. Option B is wrong because 'rollback rescue' loads the previously saved rescue configuration, not the factory-default configuration, which would be loaded with 'load factory-default' or 'rollback 0' depending on context. Option E is wrong because the rescue configuration restores the entire saved configuration, not just a subset of it.

Answer

The rescue configuration is automatically saved after every commit.

Answer

The 'rollback rescue' command loads the factory-default configuration.

Answer

The rescue configuration can be used to restore only a subset of the configuration.

Question 8

An engineer needs to check the last time the configuration was changed. Which command provides this information?

Accepted Answer

show system commit. The 'show system commit' command displays the commit history, including the date, time, and user for each configuration change. This allows the engineer to see exactly when the last configuration was committed, which is the definitive way to determine the last time the configuration was changed.

Answer

show configuration | display set

Answer

show system alarms

Answer

show system uptime

Question 9

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.

Answer

Both commands produce identical output.

Answer

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

Question 10

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.. Option A is correct because Junos uses the 'apply-groups' statement (and 'apply-groups-except') to specify which configuration group(s) a given hierarchy level should inherit from. Option C is correct because Junos configuration groups support nesting: a group can itself contain an 'apply-groups' statement, allowing one group to inherit from another group. Option D is correct because the core purpose of configuration groups is to define a reusable set of configuration statements once and have them inherited by multiple sections of the configuration, reducing duplication. Option B is incorrect because there is no limit of 10 groups per statement; Junos allows up to 50 groups to be applied at a single hierarchy level. Option E is incorrect because statements inherited from a group can be overridden by explicitly configuring the same statement in the main configuration, which takes precedence over the inherited value.

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.