JN0-106 Junos Configuration Basics Practice Test 4 — 15 Questions

Question 1

Refer to the exhibit. An engineer notices that SNMP traffic from source 10.1.1.1 is being rejected on interface ge-0/0/1. The engineer wants to allow SNMP from this source while still blocking other SNMP traffic from the 10.0.0.0/8 range. Which change should be made?

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

Accepted Answer

Insert a term 0 before term 1 to permit SNMP from 10.1.1.1. Firewall filters in Junos are evaluated sequentially from the lowest term number. By inserting a new term 0 before the existing term 1 that explicitly permits SNMP traffic (UDP ports 161/162) from source 10.1.1.1, the filter will match and accept this traffic before reaching the deny term for the 10.0.0.0/8 range. This ensures the specific host is allowed while still blocking other SNMP traffic from the broader subnet.

Answer

Add a term at the end to permit all from 10.1.1.1

Answer

Change the source-address in term 1 to 10.0.0.0/8 except 10.1.1.1

Answer

Remove the filter and apply a new filter that permits SNMP from 10.1.1.1

Question 2

An engineer needs to apply a configuration change that adds a new static route to the Junos device. The engineer wants to ensure the change takes effect immediately and is persistent across reboots. Which command should the engineer use?

Accepted Answer

commit. The 'commit' command is correct because it immediately activates the candidate configuration (including the new static route) and makes it the active configuration that survives a reboot. Junos uses a two-stage configuration model where changes are first made to the candidate configuration and then committed to become the active, persistent configuration.

Answer

load override

Answer

commit confirmed

Answer

rollback

Question 3

Which TWO statements about configuration groups in Junos are correct? (Choose two.)

Accepted Answer

Configuration groups are defined under the [edit groups] hierarchy.. Option A is correct because configuration groups in Junos are created and stored under the [edit groups] hierarchy, where each group is defined by a name and contains configuration statements that can be inherited elsewhere. Option C is correct because the apply-groups statement is the mechanism used to insert a group's configuration at a specific point in the configuration hierarchy, causing the group's statements to be inherited at that level. Option B is incorrect because configuration groups are not stored in separate files imported with the file statement; the file statement is used for loading configuration snippets from files, not for defining groups. Option D is incorrect because the replace tag is used to override inherited configuration values, not to reference a configuration group. Option E is incorrect because configuration groups can be applied at many hierarchy levels, not only at [edit interfaces].

Answer

Configuration groups are stored in separate files that are imported using the 'file' statement.

Answer

The 'replace' tag is used to reference a configuration group.

Answer

Configuration groups are applied only at the [edit interfaces] hierarchy level.

Question 4

An engineer needs to apply a configuration change to the Junos device that must survive a reboot. Which configuration mode command should be used to save the changes?

Accepted Answer

commit. The 'commit' command is the standard way to apply a candidate configuration to the active configuration in Junos. When you issue 'commit', the changes are saved to the /config/juniper.conf.gz file, which is loaded upon reboot, ensuring the configuration survives a restart.

Answer

commit confirmed

Answer

commit synchronize

Answer

commit check

Question 5

An administrator makes changes to the candidate configuration and wants to automatically revert to the previous configuration if the changes cause a loss of connectivity. Which method should be used?

Accepted Answer

Use the 'commit confirmed' command.. The 'commit confirmed' command is the correct method because it allows an administrator to commit a candidate configuration with a confirmation timeout (default 10 minutes). If connectivity is lost and the commit is not confirmed within the timeout, Junos automatically reverts to the previous configuration, ensuring the device remains reachable.

Answer

Use the 'commit check' command.

Answer

Use the 'commit synchronize' command.

Answer

Use the 'rollback' command.

Question 6

A network engineer wants to quickly restore the device to a known good configuration after a failed change. What is the recommended approach?

Accepted Answer

Use the 'rollback rescue' command.. The 'rollback rescue' command restores the device to the rescue configuration, which is a known good configuration saved explicitly for recovery after a failed change. The rescue configuration is stored as a separate file and is not affected by normal commit operations, making it the recommended approach for quick restoration.

Answer

Use the 'request system configuration rescue save' command.

Answer

Use the 'rollback 0' command.

Answer

Use the 'load override terminal' command.

Question 7

Which configuration group feature allows an administrator to apply common configuration settings to multiple interfaces without repeating the configuration?

Accepted Answer

apply-groups. The `apply-groups` statement is the correct feature because it allows an administrator to define a common configuration template within a `groups` hierarchy and then apply that template to multiple interfaces (or other configuration sections) using the `apply-groups` command. This avoids repeating the same configuration statements across individual interfaces, streamlining management and reducing errors.

Answer

groups statement

Answer

interface-range

Answer

apply-path

Question 8

An administrator needs to change a portion of the configuration by matching a pattern and replacing it with new text. Which Junos configuration mode command should be used?

Accepted Answer

replace pattern. The 'replace pattern' command in Junos configuration mode allows an administrator to search for a specific text pattern using regular expressions and replace it with new text. This is the correct command for pattern-based substitution within the configuration hierarchy, as it directly matches and replaces text without requiring manual deletion or re-entry.

Answer

rename

Answer

copy

Answer

set replace pattern

Question 9

A company has two Juniper routers in a high-availability cluster with dual Routing Engines. The administrator performs a commit on the primary RE. What is the effect of using the 'commit synchronize' command?

Accepted Answer

It commits the configuration on both Routing Engines simultaneously.. The 'commit synchronize' command on Juniper routers with dual Routing Engines ensures that the configuration is committed on both the primary and backup REs simultaneously. This is critical for maintaining configuration consistency in a high-availability cluster, as it prevents a split-brain scenario where the backup RE has a different active configuration than the primary. The command performs a full commit (including validation and activation) on both REs, not just a check.

Answer

It performs a commit check on both REs but does not activate the config.

Answer

It commits the configuration only on the primary RE.

Answer

It commits the configuration only on the backup RE.

Question 10

An engineer needs to load a full configuration from a text file onto a Junos device, replacing the entire candidate configuration. Which command should be used?

Accepted Answer

load override /path/to/config.txt. The 'load override' command replaces the entire candidate configuration with the contents of the specified text file, discarding any existing candidate changes. This is the correct choice because the engineer explicitly needs to replace the full configuration, not merge or patch it.

Answer

load set /path/to/config.txt

Answer

load patch /path/to/config.txt

Answer

load merge /path/to/config.txt

Question 11

While in configuration mode, an administrator wants to see the difference between the candidate configuration and the active configuration. Which command accomplishes this?

Accepted Answer

show | compare. The 'show | compare' command, when executed in configuration mode, displays the differences between the candidate configuration and the active (committed) configuration. This pipe filter compares the current candidate configuration against the last committed configuration, highlighting additions, deletions, and changes, which is the exact requirement for seeing the difference.

Answer

show configuration

Answer

run show configuration

Answer

show system commit

Question 12

Which THREE statements about the commit operation are correct? (Choose three.)

Accepted Answer

The 'commit check' command validates the syntax of the candidate configuration without activating it.. Option A is correct because 'commit check' performs a syntax and semantic validation of the candidate configuration and reports errors without activating or applying it, leaving the active configuration unchanged. Option B is correct because a successful commit copies the candidate configuration into the active configuration (the running configuration that the device uses), making the candidate the active one. Option C is correct because a commit can be issued with a confirmation timeout (for example, 'commit confirmed 10'), which automatically reverts to the previous configuration unless the commit is confirmed within that period. Option D is not correct because the active configuration is stored in 'juniper.conf' (with backups like juniper.conf.1.gz), while the candidate configuration is held in a separate candidate database, not in 'juniper.conf'. Option E is not correct because the rescue configuration is not saved automatically by a commit; it must be saved explicitly with 'request system configuration rescue save'.

Answer

The candidate configuration is stored in a file named 'juniper.conf' on the flash drive.

Answer

A commit operation automatically saves the rescue configuration.

Question 13

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 14

Refer to the exhibit. If the administrator now enters the command 'delete interfaces ge-0/0/0 unit 0 family inet address 192.168.1.1/24' and then commits, what will be the result?

Accepted Answer

Only the address 192.168.1.1/24 will be removed, and 192.168.1.2/24 will remain.. The 'delete' command in Junos is hierarchical and targets the exact configuration hierarchy specified. In this case, the command specifies 'address 192.168.1.1/24' under 'family inet', so only that specific address is removed. The other address (192.168.1.2/24) remains because it is a separate leaf under the same 'address' statement and is not affected by the deletion.

Answer

The commit will fail due to an attempt to delete a non-existent address.

Answer

The entire unit 0 will be deleted.

Answer

Both addresses will be removed from the configuration.

Question 15

Refer to the exhibit. An administrator wants to remove the address 10.0.0.2/24 from unit 0. Which configuration mode command achieves this without affecting other configuration?

Accepted Answer

delete interfaces ge-0/0/1 unit 0 family inet address 10.0.0.2/24. The command `delete interfaces ge-0/0/1 unit 0 family inet address 10.0.0.2/24` specifically removes only the IPv4 address 10.0.0.2/24 from the logical unit 0, leaving all other configuration (such as other addresses, VLAN tagging, or protocol families) intact. In Junos, addresses are hierarchical under `family inet address`, and deleting a specific address entry does not affect sibling addresses or the unit itself.

Answer

delete interfaces ge-0/0/1 unit 0

Answer

delete interfaces ge-0/0/1 unit 0 family inet address

Answer

delete interfaces ge-0/0/1 unit 1 family inet address 10.0.0.2/24