JN0-106 Routing Fundamentals Practice Test 5 — 15 Questions

Question 1

Which two statements are true about static routes on Juniper devices? (Choose two.)

Accepted Answer

A static route with a next-hop of an IP address requires that the next-hop be reachable.. Option A is correct because a static route whose next-hop is specified as an IP address is only installed in the routing table (and thus active) if that next-hop is resolvable and reachable via a route in inet.0; if the next-hop is unreachable, the route stays hidden. Option B is correct because Junos supports the qualified-next-hop statement, which lets you attach a separate preference to each next-hop of a static route, enabling conditional/backup routing where the secondary next-hop is used only when the primary becomes unreachable. Option C is wrong because a static route pointing at an interface (e.g., next-hop ge-0/0/0.0) is only active while that interface is up, so it is not active when the interface is down. Option D is wrong because in Junos a lower preference value is preferred, so a route with preference 5 wins over one with preference 10. Option E is wrong because static routes can perform load balancing by configuring multiple next-hops (or multiple paths) for the same destination, which are then installed as equal-cost multipath entries.

Answer

A static route with a next-hop of an interface will be active even if the interface is down.

Answer

A static route with a preference of 10 is preferred over a static route with a preference of 5.

Answer

Static routes cannot be used for load balancing.

Question 2

Refer to the exhibit. Why is the static route not active?

Accepted Answer

The static route has a higher preference than the OSPF route.. Junos uses route preference (administrative distance) to select the active route when multiple routes to the same destination exist. By default, OSPF has a preference of 10, while a static route has a preference of 5. Since a lower preference value is more preferred, the static route should normally be active. However, the question indicates the static route is not active, which implies the static route's preference has been manually set higher than OSPF's preference (e.g., static route preference > 10), causing OSPF to be selected as the active route.

Answer

The OSPF route has a lower metric.

Answer

The static route's next-hop is not reachable.

Answer

The static route is not committed.

Question 3

Refer to the exhibit. What does the 'user' type indicate about the route?

Accepted Answer

The route was manually configured.. In Junos, the 'user' type in a route table indicates that the route was manually configured, typically via a static route statement under the 'routing-options' hierarchy. This distinguishes it from routes learned dynamically through routing protocols or derived from the kernel's interface addresses.

Answer

The route is from the kernel.

Answer

The route is a default route generated by the router.

Answer

The route was learned from a routing protocol.

Question 4

A network administrator configures a default route using 'set routing-options static route 0.0.0.0/0 next-hop 10.0.0.1 preference 10' and later enables OSPF which also advertises a default route with default preference 150. Which route becomes active in the routing table?

Accepted Answer

Static route to 0.0.0.0/0 with next-hop 10.0.0.1. The static route has a preference of 10, which is lower than OSPF's default preference of 150. Junos uses the route with the lowest preference value as the active route in the routing table. Therefore, the static default route becomes active.

Answer

Neither route becomes active due to conflicting protocols

Answer

Both routes are active for ECMP load balancing

Answer

OSPF route to 0.0.0.0/0

Question 5

An engineer configures a static route to 192.168.0.0/16 with next-hop 172.16.1.1. The static route appears as 'hidden' in the routing table. What is the most likely cause?

Accepted Answer

The next-hop address 172.16.1.1 is unreachable. In JUNOS, a static route with a next-hop that is not reachable (i.e., there is no active route to the next-hop) is automatically placed in a 'hidden' state. The most likely cause is that the next-hop 172.16.1.1 is unreachable.

Answer

The static route preference is set too high

Answer

The static route has not been committed

Answer

The static route is a discard route

Question 6

Two routers running IBGP with full mesh have a routing loop for prefix 10.1.1.0/24. Both routers have an IBGP route (preference 170) for the prefix with next-hop 10.2.2.2, and an OSPF route (preference 10) for the same prefix. The OSPF next-hop on each router points to the other router's loopback interface. Which action should be taken to stop the loop while preserving BGP route advertisement?

Accepted Answer

Increase the OSPF preference for 10.1.1.0/24 to 175. Increasing the OSPF preference for 10.1.1.0/24 to 175 makes the IBGP route (preference 170) more preferred than the OSPF route. This breaks the routing loop where each router's OSPF route points to the other's loopback, while preserving the IBGP route advertisement. The loop occurs because both routers prefer the OSPF route (preference 10) over IBGP (preference 170), causing traffic to bounce between them.

Answer

Add a static route for 10.1.1.0/24 with next-hop 10.2.2.2

Answer

Configure 'set protocol bgp group internal-mesh local-address 10.2.2.2' to set next-hop to self

Answer

Use route reflection to break the loop

Question 7

An enterprise uses OSPF across multiple areas. To reduce routing table size in the backbone area, the engineer wants to advertise a single summary route for all subnets in area 2. Which configuration is appropriate?

Accepted Answer

Configure 'area 2 area-range 10.0.0.0/16' on the ABR. The 'area-range' command on an Area Border Router (ABR) allows you to summarize a set of routes from a specific area into the backbone (area 0) by advertising a single aggregate route (e.g., 10.0.0.0/16) instead of all individual subnets. This reduces the routing table size in area 0 while still providing reachability to all subnets in area 2.

Answer

Configure a virtual-link between area 2 and area 0

Answer

Configure a default route from area 2 using 'default-metric'

Answer

Use a static route for the summary and redistribute it into OSPF

Question 8

An administrator suspects that routing protocol updates are being sent to an incorrect next-hop. Which command can be used to capture and analyze the routing protocol packets on an interface?

Accepted Answer

monitor traffic interface ge-0/0/0.0. The 'monitor traffic interface' command in Junos captures live packets on a specified interface, allowing the administrator to inspect routing protocol packets (e.g., OSPF, BGP) in real time. This is the only option that directly captures and displays packet-level data to verify the next-hop IP address in routing protocol updates.

Answer

show log messages | match ospf

Answer

show route forwarding-table

Answer

show ospf neighbor detail

Question 9

A route learned via BGP appears as 'hidden' in the routing table. Which condition is most likely the cause?

Accepted Answer

The BGP next-hop is unreachable. In JUNOS, a BGP route is marked as 'hidden' in the routing table when the next-hop address is not reachable via any active route in the inet.0 table. This is a fundamental BGP path selection prerequisite: the next-hop must be resolvable (typically via an IGP or static route) for the route to be considered active and installed.

Answer

The BGP route has a higher AS path length than another route

Answer

The BGP route has been rejected by a policy

Answer

The BGP local preference is too high

Question 10

Which TWO statements are true about the default route in JunOS? (Choose two.)

Accepted Answer

It has a prefix of 0.0.0.0/0. Option A is correct because the default route in JunOS (and IP generally) is the all-zeros prefix 0.0.0.0/0, which matches any destination not covered by a more specific route. Option D is correct because a default route can be manually configured as a static route, e.g., 'set routing-options static route 0.0.0.0/0 next-hop <ip>', making it a common way to provide a gateway of last resort. Option B is wrong because the default route can be either statically configured or dynamically learned (e.g., via OSPF, BGP, or IS-IS), not only dynamically. Option C is wrong because the default preference for a static route in JunOS is 5, not 0 (0 is reserved for directly connected routes). Option E is wrong because the default route is not automatically present in the routing table; it must be explicitly configured or learned.

Answer

It can only be learned dynamically

Answer

Its default preference is 0

Answer

It is always present in the routing table

Question 11

Which TWO factors are directly used when comparing route preferences in JunOS? (Choose two.)

Accepted Answer

Metric (or cost). In Junos, route preference (also called administrative distance) is the primary tie-breaker used to compare routes from different protocols, so option E (Preference value) is directly used — lower preference wins, e.g., direct=0, static=5, OSPF internal=10, RIP=100. When two routes come from the same protocol, the protocol's metric/cost is compared, so option C (Metric or cost) is also directly used, e.g., OSPF cost or RIP hop count. Option A (Next-hop reachability) is a validity condition for installing a route, not a comparison factor between competing routes. Option B (Number of hops) is only a metric within protocols like RIP, not a universal Junos comparison factor. Option D (Prefix length) is used for longest-match forwarding lookups in the forwarding table, not for route preference comparison in the routing table.

Answer

Next-hop reachability

Answer

Number of hops

Answer

Prefix length

Question 12

Refer to the exhibit. Why is the route for 192.168.1.0/24 hidden?

Accepted Answer

The next-hop is unreachable. A route is hidden in the JUNOS routing table when its next-hop is unreachable. The show route command displays only active routes; if the next-hop address is not reachable via any active interface or route, the route is suppressed (hidden) and not used for forwarding. This is a fundamental behavior of JUNOS route selection and differs from Cisco IOS, which may still display such routes.

Answer

The route has a higher metric

Answer

The route has a lower preference

Answer

The route is not committed

Question 13

Refer to the exhibit. The route for 192.168.0.0/16 is hidden. What is the most likely reason?

Accepted Answer

The BGP next-hop is unreachable. In JUNOS, a BGP route is hidden when the next-hop address is not reachable via any active route in the routing table. The router cannot install the route into the forwarding table because it lacks a valid path to the next-hop, causing the route to be marked as hidden. This is a common issue when the next-hop is not covered by a directly connected or static route, or when the IGP route to the next-hop is missing.

Answer

The route has a lower local preference

Answer

The route has a longer AS path

Answer

The route has a higher MED value

Question 14

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 15

A network administrator is troubleshooting a missing route in the routing table. The route is learned via OSPF, and the OSPF neighbor adjacency is up. Which command would help determine if OSPF received the route?

Accepted Answer

show ospf database. The OSPF link-state database (LSDB) contains all received LSAs, including Type 1 (Router) and Type 3 (Summary) LSAs that advertise routes. Even if a route is not installed in the routing table (e.g., due to a higher administrative distance or a missing route preference), the 'show ospf database' command confirms whether OSPF has received the LSA carrying that route. This directly answers the question of whether OSPF received the route, independent of route installation.

Answer

show route protocol ospf

Answer

show ospf neighbor

Answer

show interface terse