JN0-106 Practice Test 18 — 15 Questions

Question 1

A technician needs to load a new configuration file that replaces only the specific hierarchy paths present in the file, leaving all other existing configuration unchanged. Which load statement is appropriate?

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

Accepted Answer

load merge. The 'load merge' command is correct because it merges the contents of the specified configuration file with the current candidate configuration, adding or updating only the hierarchy paths present in the file while preserving all other existing configuration. This matches the requirement to replace only specific hierarchy paths without affecting the rest of the configuration.

Answer

load replace

Answer

load set

Answer

load override

Question 2

A network administrator wants to filter routes from being installed in the routing table based on certain criteria. Which Junos feature should be used?

Accepted Answer

Routing policy (import). B is correct because a routing policy with an import term is the Junos mechanism to control which routes are accepted into the routing table from a routing protocol or a peer. By defining match conditions (e.g., prefix, community, AS path) and an action (accept or reject), the administrator can filter routes before they are installed. This is the standard Junos approach for route filtering at the routing table level.

Answer

Community list

Answer

Prefix list

Answer

Firewall filter

Question 3

Which THREE statements about the 'commit' command are correct?

Accepted Answer

The 'commit check' command validates the syntax of the candidate configuration.. Option A is correct because 'commit check' parses and validates the candidate configuration's syntax and semantics without actually activating it, so errors are reported before a real commit. Option B is correct because on a dual-RE (redundant Routing Engine) system, 'commit synchronize' commits the candidate configuration on both Routing Engines, keeping the primary and backup REs in sync. Option E is correct because 'commit confirmed 5' activates the configuration but automatically rolls back to the previous configuration after 5 minutes unless the administrator confirms it with a subsequent 'commit'. Option C is wrong because 'commit full' forces a full commit that re-evaluates the entire configuration and does perform validation, rather than skipping it. Option D is wrong because multiple users can be in configuration mode simultaneously; the 'commit' command is not restricted to a single user, though a commit lock may be used to prevent conflicting changes.

Answer

The 'commit full' command activates the configuration without performing any validation.

Answer

The 'commit' command can only be issued when no other users are in configuration mode.

Question 4

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 5

An engineer needs to check the current system uptime on a Juniper device running Junos OS. Which command should they use?

Accepted Answer

show system uptime. The correct command to check current system uptime on a Juniper device running Junos OS is 'show system uptime'. This command displays the time since the system was last booted, as well as the current time and the time since the routing protocol process (rpd) started. It is the standard operational command for this specific metric.

Answer

show system status

Answer

show system health

Answer

show system resources

Question 6

You configure an aggregate route for 172.16.0.0/16. What must exist for this aggregate to be active in the routing table?

Accepted Answer

A contributing route (more specific route within the aggregate range). The correct option is C: a contributing route (a more specific route within the aggregate range) must exist for the aggregate to become active. In Junos, an aggregate route is only installed into the routing table when at least one more-specific route covered by the aggregate prefix is present in the routing table; for 172.16.0.0/16, that means a route such as 172.16.1.0/24 must be learned or configured. Option A is incorrect because a directly connected interface on the exact aggregate subnet is not required, and a more-specific connected route would itself serve as the contributing route. Option B is incorrect because a static route to the aggregate prefix does not activate the aggregate and would conflict with the aggregate's purpose. Option D is incorrect because aggregate routes are not unconditionally active; they depend on the presence of contributing routes.

Answer

A directly connected interface on that subnet

Answer

A static route to the aggregate prefix

Answer

Nothing; the aggregate is always active once committed.

Question 7

Refer to the exhibit. The interface ge-0/0/0 is configured as shown, but the interface is operationally down. Which command would provide the most detailed information about the interface status and errors?

Accepted Answer

show interfaces ge-0/0/0 extensive. The correct option is D, 'show interfaces ge-0/0/0 extensive', because the extensive keyword produces the most detailed output for a Junos interface, including physical and logical interface status, error counters (input/output errors, drops, framing, CRC, collisions), MAC/PHY details, and operational flags needed to diagnose why ge-0/0/0 is operationally down. Option A, 'show interfaces ge-0/0/0', gives a standard summary with basic status and counters but omits the deeper diagnostic detail. Option B, 'show configuration interfaces ge-0/0/0', only displays the configured statements and cannot reveal live operational state or errors. Option C, 'show interfaces ge-0/0/0 terse', provides a brief one-line-per-interface summary, which is the least detailed for troubleshooting.

Answer

show interfaces ge-0/0/0

Answer

show configuration interfaces ge-0/0/0

Answer

show interfaces ge-0/0/0 terse

Question 8

Which TWO statements are correct regarding the Junos OS configuration hierarchy?

Accepted Answer

The 'show | compare' command displays differences between the candidate and active configurations.. Option C is correct because the 'show | compare' command in Junos displays the differences between the candidate configuration and the active (committed) configuration, allowing operators to review pending changes before committing. Option E is correct because the 'set' command is used in configuration mode to modify the candidate configuration, adding or changing statements in the hierarchy. Option A is incorrect because 'commit check' only validates the candidate configuration for syntax and semantic errors without applying it; the 'commit' command applies it to the active configuration. Option B is incorrect because 'load replace' replaces the entire candidate configuration with the contents of a file, whereas 'load merge' merges a file into the candidate configuration. Option D is incorrect because 'rollback 0' reverts the candidate configuration to the currently active configuration, discarding uncommitted changes; 'rollback 1' reverts to the previous committed configuration.

Answer

The 'commit check' command applies the candidate configuration to the active configuration.

Answer

The 'load replace' command merges a configuration file into the candidate configuration.

Answer

The 'rollback 0' command reverts the candidate configuration to the previous state.

Question 9

During a routing table lookup, a packet matches both a static route and an OSPF route to the same destination. Which route will be installed in the forwarding table?

Accepted Answer

The static route, because it has a lower preference value.. In Junos, the route with the lowest preference value is installed in the forwarding table. Static routes have a default preference of 5, while OSPF internal routes have a default preference of 10. Therefore, the static route is preferred and installed.

Answer

Both routes, if they are equal-cost.

Answer

The route with the higher preference value.

Answer

The OSPF route, because OSPF is a dynamic routing protocol.

Question 10

A technician needs to upgrade the Junos OS on a device that is part of a redundant cluster. Which approach minimizes traffic disruption?

Accepted Answer

Upgrade one node at a time, ensuring the cluster remains redundant.. Upgrading one node at a time in a redundant cluster ensures that at least one node remains active to handle traffic while the other is being upgraded. This approach maintains cluster redundancy and minimizes traffic disruption, as the active node continues forwarding traffic using the gratuitous ARP or VRRP mechanisms, and the upgraded node rejoins the cluster after reboot.

Answer

Use 'request system software add' on both nodes at the same time.

Answer

Upgrade both nodes simultaneously to reduce maintenance time.

Answer

Use the 'commit synchronize' command to keep configurations in sync after upgrade.

Question 11

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

Question 12

After a series of configuration changes, an engineer wants to see only the lines that will be added or modified when the candidate is committed. Which command achieves this?

Accepted Answer

show | compare. The 'show | compare' command displays the differences between the candidate configuration and the active configuration, showing only the lines that will be added, modified, or deleted upon commit. This is the standard Junos method for reviewing pending changes before committing them.

Answer

show configuration | except

Answer

show configuration | display set

Answer

commit check | match

Question 13

A medium-sized enterprise has its headquarters (HQ) and a remote branch office connected via a dedicated point-to-point link. The HQ router (Juniper MX) has interface ge-0/0/1 with IP 10.0.0.1/30 connected to the branch router (Juniper SRX) interface ge-0/0/0 with IP 10.0.0.2/30. The branch LAN is 192.168.2.0/24, and the HQ LAN is 10.0.1.0/24. The branch router has a default route pointing to 10.0.0.1. The HQ router has a static route for 192.168.2.0/24 with next-hop 10.0.0.2, but it was recently changed incorrectly to point to 10.0.0.10 due to a configuration error. Users at the branch report that they can access the internet via the HQ router but cannot reach the HQ LAN's file server at 10.0.1.100. From the HQ router, you can ping the branch router's interface IP (10.0.0.2) successfully, but you cannot ping any device in the branch LAN (192.168.2.0/24). You check the routing table on the HQ router and see that the static route for 192.168.2.0/24 points to 10.0.0.10. What is the most appropriate corrective action?

Accepted Answer

Change the static route on the HQ router to point to 10.0.0.2.. The correct action is D: change the static route on the HQ router for 192.168.2.0/24 to point to 10.0.0.2, the actual next-hop IP of the branch router's ge-0/0/0 interface. The HQ router currently has the route pointing to 10.0.0.10, which is not a valid next hop on the 10.0.0.0/30 point-to-point link, so traffic destined for the branch LAN is dropped or unresolved even though 10.0.0.2 is directly reachable. Correcting the next hop restores forwarding to 192.168.2.0/24 and allows return traffic to reach the HQ LAN. Option A is unnecessary because the branch router already has a default route via 10.0.0.1, which covers 10.0.1.0/24. Option B is wrong because removing the HQ static route would not fix the misconfigured next hop and would leave the branch LAN unreachable from HQ. Option C is irrelevant because proxy ARP does not repair an invalid static route next hop.

Answer

Add a static route on the branch router for 10.0.1.0/24 pointing to 10.0.0.1.

Answer

Remove the static route and rely on the default route on the branch router.

Answer

Enable proxy ARP on the HQ router's ge-0/0/1 interface.

Question 14

Which two factors does Junos use to select the best route when multiple routes to the same prefix exist? (Choose two.)

Accepted Answer

Route preference. Junos route selection first compares route preference (administrative distance), so option A is correct because the route with the lower preference value (for example, direct 0, static 5, OSPF 10, RIP 100, BGP 170) wins before any protocol-specific metric is considered. If routes have equal preference, Junos then compares the metric, so option D is correct because the lower metric is preferred within the same protocol or routing table. Options B, C, and E are not the two primary Junos best-route selection factors: next-hop type, hop count, and route age are not used as the general tie-breakers in the Junos route selection algorithm.

Answer

Next-hop type

Answer

Number of hops

Answer

Route age

Question 15

An administrator notices that the routing table is not updating as expected. Which command should be used to verify the routing table contents?

Accepted Answer

show route. The 'show route' command displays the routing table, which contains all active routes learned via static configuration, direct interfaces, or dynamic routing protocols such as OSPF, IS-IS, BGP, and RIP. If the routing table is not updating as expected, this command allows the administrator to verify the current routes, their next hops, and protocol sources to identify missing or incorrect entries.

Answer

show log

Answer

show system storage

Answer

show interfaces