JN0-106 Practice Test 4 — 10 Questions

Question 1

A Juniper device receives several routes to the same destination prefix from different routing protocols. Which parameter is used first to select the active route?

Accepted Answer

Route preference (administrative distance). When a Juniper device receives multiple routes to the same destination prefix from different routing protocols, the route preference (also known as administrative distance) is the first tiebreaker used to select the active route. Each protocol has a default preference value (e.g., OSPF internal routes have a preference of 10, while static routes have a preference of 5), and the route with the lowest preference is chosen as active. This occurs before any metric or other path attribute is considered.

Answer

Metric

Answer

AS path length

Answer

Local preference

Question 2

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 3

A company runs a Juniper SRX firewall cluster consisting of two nodes (node0 primary, node1 secondary). The cluster has been stable. During maintenance, you modify the configuration on node0 and commit. After the commit, the cluster status shows node1 as 'ineligible'. You suspect a configuration mismatch. What should you do to synchronize the configuration without disrupting traffic?

Accepted Answer

On the primary node, execute 'commit synchronize'.. The 'commit synchronize' command on the primary node (node0) pushes the active configuration to the secondary node (node1) and commits it on both nodes, ensuring configuration consistency without requiring a reboot or traffic disruption. In a Juniper SRX cluster, the primary node is the authoritative source for configuration synchronization, and this command is the standard method to resolve a configuration mismatch that causes a node to become 'ineligible'.

Answer

Reboot both nodes to force synchronization.

Answer

Manually copy the configuration file from primary to secondary.

Answer

On the secondary node, execute 'commit synchronize'.

Question 4

A network engineer suspects a hardware issue on an interface. Which command provides the most detailed hardware error counters, including CRC errors, framing errors, and runts?

Accepted Answer

show interfaces extensive. The 'show interfaces extensive' command provides the most detailed hardware error counters for a Junos interface, including CRC errors, framing errors, and runts. This command displays per-interface statistics at the physical layer, such as input errors, output errors, and specific error types like frame, runts, giants, and CRC errors, which are essential for diagnosing hardware issues.

Answer

show interfaces diagnostics optics

Answer

show interfaces detail

Answer

show log messages

Question 5

A router receives a packet with destination IP 10.1.1.100. The routing table contains two entries: a static route to 10.1.1.0/24 via 192.168.1.1, and an OSPF route to 10.1.1.0/25 via 192.168.2.1. Which route will the router use?

Accepted Answer

The OSPF route to 10.1.1.0/25. The router will use the OSPF route to 10.1.1.0/25 because it has a longer prefix length (/25) than the static route (/24). Juniper Junos uses the most specific (longest) prefix match in the routing table, regardless of administrative distance or protocol preference. The destination IP 10.1.1.100 falls within the 10.1.1.0/25 range (10.1.1.0–10.1.1.127), so the /25 route is more specific and thus preferred.

Answer

The router drops the packet due to a routing conflict

Answer

The static route to 10.1.1.0/24

Answer

Both routes are used for load balancing

Question 6

Refer to the exhibit. A host connected to ge-0/0/1 cannot reach a host connected to ge-0/0/2 even though both are in VLAN10. What is the most likely cause?

Accepted Answer

The hosts are configured with IP addresses on different subnets.. Although both hosts are in the same VLAN and can communicate at Layer 2 (MAC addresses), IP communication requires them to be on the same IP subnet. If the hosts have IP addresses on different subnets, they will attempt to use a default gateway for routing. Without a router or IRB interface configured, the traffic cannot be delivered, leading to unreachability.

Answer

VLAN10 is not defined in the global VLAN configuration.

Answer

An IRB interface for VLAN10 is not configured.

Answer

The interface ge-0/0/2 is configured as a trunk port.

Question 7

Refer to the exhibit. What is the most likely cause of the error?

Accepted Answer

The policy-statement 'test' contains a syntax error in the protocol match condition.. The error message in the exhibit indicates a syntax error in the policy-statement 'test' when using the protocol match condition. In Junos, the 'protocol' match condition requires a valid protocol name (e.g., 'bgp', 'ospf', 'static'), and if an invalid or misspelled protocol is specified, the commit check fails with a syntax error. This is a common mistake when configuring policy-options, as the Junos CLI validates the protocol against a predefined list.

Answer

The IP address 1.1.1.1/32 is already in use.

Answer

The candidate configuration has no errors and this is a warning.

Answer

The commit check command requires user confirmation.

Question 8

A network must forward traffic to 10.1.1.0/24 through a specific next-hop 192.168.1.1, even if a dynamic route with a lower preference is available. Which configuration will achieve this?

Accepted Answer

Configure a static route to 10.1.1.0/24 with next-hop 192.168.1.1 and preference 5.. A static route can be configured with a preference value lower than any dynamic routing protocol's default preference. In Junos, the default preference for OSPF internal routes is 10, for IS-IS level 1 is 15, for RIP is 100, and for BGP is 170. By setting the static route to 10.1.1.0/24 with next-hop 192.168.1.1 and preference 5, it will have a lower preference value than these defaults. Therefore, even if a dynamic route with a lower preference (i.e., a smaller number but still greater than 5) exists, the static route will be installed in the routing table and used for forwarding, satisfying the requirement to always forward traffic through the specified next-hop.

Answer

Configure the dynamic protocol to export the route with a metric of 1.

Answer

Configure a filter to reject the dynamic route.

Answer

Configure a static route to 10.1.1.0/24 with next-hop 192.168.1.1 and preference 15.

Question 9

A network engineer configures a static route to a remote network. They want the route to be automatically removed from the routing table if the directly connected interface used to reach the next hop fails. Which configuration approach should be used?

Accepted Answer

Configure the next-hop as the interface name.. Configuring the next-hop as an interface name (e.g., ge-0/0/0) creates a static route that is automatically removed from the routing table when that interface goes down. This is due to the route being 'qualified' by the interface's operational state; if the interface fails, the route is withdrawn. In contrast, using an IP address as the next-hop does not tie the route to the interface's state, so the route remains even if the interface fails, as long as the next-hop is reachable via another path.

Answer

Configure a higher metric on the static route.

Answer

Configure a preference of 0 on the static route.

Answer

Configure the next-hop as an IP address.

Question 10

Which command is used to verify that the current active configuration is the same as the candidate configuration?

Accepted Answer

show | compare. The command `show | compare` displays the differences between the candidate configuration and the active (committed) configuration. If there are no differences, the candidate configuration is identical to the active configuration. This is the correct way to verify whether the candidate configuration matches the active configuration in Junos.

Answer

commit check

Answer

show configuration

Answer

show system configuration