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CCNA Routing Fundamentals Questions

75 of 97 questions · Page 1/2 · Routing Fundamentals · Answers revealed

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1
MCQmedium

An administrator executes 'show route 192.168.1.0/24' and sees no output, but the route is configured. Which command should be used to display the reason the route is not active?

A.show route hidden
B.show log messages
C.show route protocol static
D.show route forwarding-table
AnswerA

This command reveals hidden routes with reasons for their status.

Why this answer

The correct answer is A. The command 'show route hidden' displays all routes that are not active due to issues like unreachable next-hops, rejection, etc. Option B shows only static routes, not necessarily hidden.

Option C shows the forwarding table, not the routing table. Option D shows log messages, not route status.

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2
MCQmedium

A Juniper MX router is configured with multiple routing instances. In which scenario would an interface be automatically placed in a routing instance?

A.When the interface is configured with an IP address from the instance's address family.
B.When the interface is associated with the default instance.
C.When the interface is configured under the instance's `interface` statement.
D.When the routing instance type is virtual-router and the interface is a physical interface.
AnswerC

Interfaces must be explicitly added to a routing instance using the `interface` command.

Why this answer

Option C is correct because interfaces must be explicitly configured under the routing instance's `interface` statement. Option A is wrong because IP addressing alone does not assign to an instance. Option B is wrong because the default instance is the master instance, not an automatic placement into another instance.

Option D is wrong because virtual-router type also requires explicit configuration.

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3
MCQeasy

A router has an OSPF route to 10.10.10.0/24 with preference 10 and a static route to the same prefix with preference 5. Which route is active in the routing table?

A.The OSPF route
B.The static route
C.Neither route
D.Both routes
AnswerB

Lower preference number is preferred; static (5) beats OSPF (10).

Why this answer

The correct answer is B. Junos uses route preference to select the best route. Static routes have a default preference of 5, which is lower than OSPF's internal preference of 10, so the static route is preferred.

Option A is wrong because OSPF has a higher preference. Option C is wrong because only one route is active (unless ECMP, but preferences differ). Option D is wrong because one route is active.

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4
MCQeasy

A network engineer is troubleshooting a connectivity issue and wants to see the active routes in the routing table. Which Junos CLI command should they use?

A.show log messages
B.show configuration
C.show interface
D.show route
AnswerD

Displays the routing table.

Why this answer

The 'show route' command displays the active routing table entries, including directly connected, static, and dynamic routes learned via protocols like OSPF, BGP, or IS-IS. This is the correct command to view the active routes the device uses for forwarding traffic.

Exam trap

The trap here is that candidates familiar with Cisco IOS might confuse 'show ip route' with Junos's 'show route' but incorrectly choose 'show configuration' thinking it shows routing information, or 'show interface' thinking it shows connected routes, when only 'show route' provides the complete active routing table.

How to eliminate wrong answers

Option A is wrong because 'show log messages' displays system log messages (syslog) for troubleshooting events, not the routing table. Option B is wrong because 'show configuration' displays the current configuration, not the operational routing table. Option C is wrong because 'show interface' displays interface status and statistics, not routing information.

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5
MCQmedium

A router has two routes to the same destination: one with preference 10 and metric 5, and another with preference 15 and metric 3. Which route will be installed in the forwarding table?

A.The route with preference 10.
B.The route with metric 3.
C.Neither route is installed.
D.Both routes are installed if ECMP is enabled.
AnswerA

Preference is the primary selection criterion.

Why this answer

In Junos, the route preference (administrative distance) is the primary criterion for selecting the best route to a destination. The route with preference 10 is preferred over the route with preference 15, regardless of metric values. The route with preference 10 is installed in the forwarding table.

Exam trap

The trap here is that candidates often confuse metric with preference, assuming a lower metric always wins, but Junos prioritizes preference over metric in route selection.

How to eliminate wrong answers

Option B is wrong because metric is only used as a tiebreaker when preferences are equal; a lower metric (3) does not override a higher preference (15). Option C is wrong because one route will always be installed when there are valid routes to the same destination, unless both are rejected by policy or have the same preference and metric with ECMP disabled. Option D is wrong because ECMP (Equal-Cost Multipath) requires routes to have equal preference and equal metric; here preferences differ (10 vs 15), so ECMP does not apply.

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6
MCQmedium

A static route is configured with next-hop 10.0.0.1, but the route does not appear in the routing table. The interface ge-0/0/0 has IP 192.168.1.2/24 and is up. What is the most likely reason?

A.The static route has a preference of 5.
B.The route is hidden due to an import policy.
C.The static route is configured with the 'discard' option.
D.The next-hop IP is not on a directly connected subnet.
AnswerD

The next-hop is not reachable via a directly connected interface, so the route is not installed unless 'resolve' is used.

Why this answer

The next-hop 10.0.0.1 is not on a directly connected subnet (192.168.1.0/24). For a static route to be installed, the next-hop must be reachable via a directly connected interface unless the 'resolve' option is used. Option A is not a problem.

Option C is unlikely. Option D would not prevent route installation if next-hop is reachable.

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7
Multi-Selectmedium

Which two factors determine whether a route is active for a given destination when multiple routes from different protocols exist? (Choose two.)

Select 2 answers
A.Metric
B.Route preference
C.Route origin
D.Next-hop reachability
E.Local preference
AnswersB, D

Route preference is used to compare routes from different protocols; lower preference is preferred.

Why this answer

B is correct because Junos uses route preference (administrative distance) as the primary tiebreaker when multiple routing protocols offer routes to the same destination. The route with the lowest preference value is installed into the routing table as the active route. D is correct because even if a route has the best preference, it must have a reachable next hop to be considered active; if the next hop is unreachable, the route is hidden and not used.

Exam trap

The trap here is that candidates often confuse metric with preference, thinking metric is used to compare routes from different protocols, but Junos uses preference as the first tiebreaker, and metric only applies within the same protocol.

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8
MCQeasy

An engineer wants to configure a static route that will be used only if the primary route (learned via OSPF) becomes unavailable. Which feature should be used?

A.Floating static route with a higher preference.
B.Static route with a lower metric.
C.Reverse path forwarding.
D.Routing policy.
AnswerA

A higher preference (e.g., 15) makes the static route less preferred than OSPF (10), so it acts as a backup.

Why this answer

Option B is correct because a floating static route uses a higher preference so it is less preferred than OSPF and only becomes active when OSPF fails. Option A is wrong because metric is not comparable across protocols. Option C is wrong because RPF is unrelated.

Option D is wrong because routing policy is too broad and not the specific feature.

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9
Drag & Dropmedium

Order the steps to reset the root password on a Junos device via the console.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order

Why this order

Root password recovery requires boot interruption and selecting the recovery option from the boot menu.

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10
Multi-Selecteasy

Which TWO statements about static routes in Junos OS are correct? (Choose two.)

Select 2 answers
A.Two static routes to the same destination with the same preference will result in an active/backup scenario.
B.A static route can have a next-hop specified as an interface name for point-to-point interfaces.
C.A static route can use the 'reject' next-hop to drop traffic matching the route.
D.The default preference for a static route is 10.
E.A static route must always include a next-hop address.
AnswersB, C

For point-to-point interfaces like serial, you can use interface name as next-hop.

Why this answer

Options A and D are correct. A: A static route with a next-hop of 'reject' installs a reject route to prevent traffic. D: A static route can have a next-hop that is an interface name (e.g., ge-0/0/0) for point-to-point interfaces.

B is incorrect; the default preference is 5, not 10. C is incorrect; a static route can be configured without a next-hop (though not typical) but the statement is too absolute. E is incorrect; two static routes to the same destination with equal preferences result in ECMP, not active/backup.

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11
MCQeasy

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

A.The route has a higher metric
B.The route has a lower preference
C.The route is not committed
D.The next-hop is unreachable
AnswerD

Hidden static routes indicate that the next-hop is not reachable.

Why this answer

The route is hidden because its next-hop is unreachable. Option B is correct. Option A is incorrect because the metric is the same as other static routes.

Option C is incorrect because the route appears in the routing table. Option D is incorrect because the preference is 10, same as other routes.

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12
MCQeasy

An administrator configures a static route to 192.168.2.0/24 with next-hop 10.0.0.1. The route does not appear in the routing table. What is the most likely cause?

A.The next-hop 10.0.0.1 is not reachable.
B.The static route has a higher preference than an existing dynamic route.
C.The configuration was not committed.
D.The prefix 192.168.2.0/24 already exists in the forwarding table.
AnswerA

A static route is only installed if the next-hop is reachable via an active route.

Why this answer

The correct answer is B. A static route requires a reachable next-hop to be installed. If the next-hop is not reachable (e.g., no active route to 10.0.0.1), the route is hidden.

Option A is incorrect because static routes have a low preference (5) and would override dynamic routes. Option C is incorrect because a commit would show an error if the configuration failed. Option D is incorrect because the route would be hidden, not in the forwarding table.

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13
Matchingmedium

Match each Junos routing protocol to its primary characteristic.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts
Matches

Link-state IGP using Dijkstra algorithm

Link-state IGP used in large ISPs

Path-vector EGP used for inter-AS routing

Distance-vector IGP using hop count

Manually configured route with next-hop

Why these pairings

These are common routing protocols and route types in Junos.

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14
MCQmedium

An engineer observes that traffic destined to 203.0.113.0/24 is being load-balanced across two equal-cost paths via OSPF. The engineer wants to ensure that all traffic for this prefix uses only one path unless the primary path fails. Which configuration change should be made?

A.Configure a static route for 203.0.113.0/24 with a lower preference.
B.Set the OSPF metric on the backup interface to a higher value.
C.Use policy-options to set a higher preference for one of the paths.
D.Modify the load-balance configuration under forwarding-options.
AnswerB

Increasing metric on one interface makes it less preferred, so OSPF will use the lower metric path as primary.

Why this answer

Option B is correct because increasing the OSPF metric on the backup interface makes that path less preferred in the SPF calculation, breaking the equal-cost multipath (ECMP) condition. OSPF selects routes based on the lowest metric; by raising the metric on one interface, the engineer ensures only the lower-metric path is used for forwarding, with automatic failover to the backup path if the primary fails.

Exam trap

The trap here is that candidates mistakenly think modifying load-balancing or preference settings can break ECMP, but OSPF ECMP is solely determined by equal metric values; only changing the metric (or using a feature like per-packet load balancing) directly controls path selection.

How to eliminate wrong answers

Option A is wrong because configuring a static route with a lower preference (administrative distance) would override the OSPF-learned route entirely, but static routes do not dynamically fail over; they lack OSPF's link-state awareness and would require manual intervention or additional tracking to handle failures. Option C is wrong because policy-options can modify route preference (administrative distance) for OSPF routes, but preference is not used in OSPF's SPF metric-based path selection; changing preference would affect route selection among different protocols, not ECMP within OSPF. Option D is wrong because modifying the load-balance configuration under forwarding-options (e.g., `maximum-paths`) controls how many ECMP paths are used, but it does not break the equal-cost condition; if both paths have the same metric, OSPF will still install them as ECMP unless the metric is changed.

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15
MCQmedium

A network engineer is troubleshooting a reachability issue between two directly connected routers. Both routers have IP addresses configured on their interfaces and the interfaces are up. Which command would the engineer use to verify the routing table entry for the remote network?

A.show route
B.show interfaces terse
C.show configuration interfaces
D.show arp
AnswerA

Displays the routing table, including directly connected and learned routes.

Why this answer

The 'show route' command displays the routing table, which contains all active routes learned via static configuration, direct connections, or dynamic routing protocols. To verify the routing table entry for a specific remote network, this command shows the next-hop IP address, interface, and route preference/metric, directly confirming whether the remote network is reachable.

Exam trap

The trap here is that candidates confuse verifying interface configuration or ARP entries with verifying routing table entries, assuming that if interfaces are up and IPs are configured, the route must exist, but the routing table must be explicitly checked to confirm the remote network is reachable.

How to eliminate wrong answers

Option B is wrong because 'show interfaces terse' displays interface status and IP addresses but does not show routing table entries or reachability to remote networks. Option C is wrong because 'show configuration interfaces' displays the configured interface settings (like IP addresses and VLANs) but not the active routing table or learned routes. Option D is wrong because 'show arp' displays the ARP cache, which maps IP addresses to MAC addresses for directly connected neighbors, but does not show routing table entries for remote networks.

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16
MCQmedium

A network administrator configures the following: `set routing-options static route 0.0.0.0/0 next-hop 192.168.1.1`. After committing, the administrator notices that the default route is not active. What could be the reason?

A.The route preference is set to 170.
B.The route is not exported into the forwarding table.
C.The next-hop 192.168.1.1 is not reachable.
D.The router already has a default route learned via DHCP.
AnswerC

If the next-hop is not in the routing table, the static route is not active.

Why this answer

Option D is correct because the next-hop address may not be reachable. Option A is wrong because if a DHCP default route existed, the static route would be preferred due to lower preference. Option B is wrong since a higher preference number makes a route less preferred, but the route would still be active if it's the only route.

Option C is wrong because static routes are automatically placed in the forwarding table if active.

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17
MCQeasy

A router has multiple equal-cost paths to the same destination. Which statement describes how Junos load balances traffic across these paths?

A.Junos uses per-flow load balancing based on source and destination IP and port.
B.Junos uses the route with the lowest next-hop IP.
C.Junos installs only one route and ignores the others.
D.Junos uses per-packet load balancing by default.
AnswerA

Junos defaults to per-flow load balancing using a hash of source and destination IP addresses and ports.

Why this answer

Junos uses per-flow load balancing by default based on source/destination IP and port. Option A (per-packet) is not default. Option B is false.

Option D is not the primary method for ECMP.

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18
MCQeasy

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?

A.show route protocol ospf
B.show ospf neighbor
C.show ospf database
D.show interface terse
AnswerC

This command shows LSAs in the OSPF database, including received routes.

Why this answer

The 'show ospf database' command displays LSAs received by OSPF, indicating if the route was received. Option A shows neighbors only. Option C shows only active routes.

Option D shows interface status.

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19
Multi-Selectmedium

Which THREE factors are considered when Junos selects the active route among multiple routes to the same destination?

Select 3 answers
A.Metric
B.Route age
C.Interface bandwidth
D.Next-hop address
E.Preference
AnswersA, D, E

Metric is considered when preferences are equal.

Why this answer

Junos uses preference first; if equal, metric; if still equal, next-hop address as tie-breaker. Route age and interface bandwidth are not considered.

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20
MCQhard

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

A.Community list
B.Routing policy (import)
C.Prefix list
D.Firewall filter
AnswerB

Import policies can filter routes before they enter the routing table.

Why this answer

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.

Exam trap

The trap here is confusing a match condition (like a prefix list or community list) with the actual Junos feature that applies the filter (the routing policy), leading candidates to select a component rather than the complete mechanism.

How to eliminate wrong answers

Option A is wrong because a community list is a named set of BGP community values used as a match condition within a routing policy, not a standalone feature to filter routes from the routing table. Option C is wrong because a prefix list is a named list of prefixes used as a match condition within a routing policy, not a direct filtering mechanism for the routing table. Option D is wrong because a firewall filter operates on packets at the interface level (Layer 3/Layer 4), not on routing information or the routing table.

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21
Multi-Selecthard

Which THREE factors influence the selection of the active route in the Junos routing table when multiple routes exist for the same destination? (Choose three.)

Select 3 answers
A.Route preference (administrative distance).
B.The routing protocol from which the route originated.
C.Number of next-hops available for each route.
D.Metric value (if from the same routing protocol).
E.Bandwidth of the outgoing interface.
AnswersA, B, D

Lower preference is preferred.

Why this answer

Options B, C, and E are correct. B: Route preference (administrative distance) is the primary tiebreaker. C: Metric (e.g., OSPF cost) is considered after preference if routes are from the same protocol.

E: The route's source protocol (e.g., OSPF vs Static) determines default preference values. A is incorrect; the routing table does not consider interface bandwidth in route selection. D is incorrect; the number of next-hops is not a selection criterion; all equal-cost next-hops are used.

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22
MCQmedium

Refer to the exhibit. If the primary next-hop (192.168.1.1) becomes unreachable, what will happen to the route?

A.The route is removed from the routing table.
B.The route remains but with the primary next-hop marked as unreachable.
C.The secondary next-hop (192.168.2.1) will be used.
D.The route becomes hidden.
AnswerC

When the primary is unreachable, the secondary next-hop with higher preference becomes active.

Why this answer

With qualified-next-hop configured with different preferences, the route uses the next-hop with the lowest preference (10) as primary. When that next-hop is unreachable, the route will use the next-hop with preference 20 as the active next-hop.

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23
Multi-Selecteasy

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

Select 2 answers
A.It has a prefix of 0.0.0.0/0
B.It can only be learned dynamically
C.Its default preference is 0
D.It can be added via a static route
E.It is always present in the routing table
AnswersA, D

The default route matches all destinations.

Why this answer

The default route has prefix 0.0.0.0/0 and can be configured as a static route. Options A and E are correct. Option B is incorrect because the default route is not always present.

Option C is incorrect because the default preference for a static default is 10, not 0. Option D is incorrect because the default route can be learned dynamically or statically.

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24
MCQmedium

A network is experiencing intermittent routing loops. The engineer discovers that routes are being redistributed from OSPF into BGP and then from BGP back into OSPF on different routers. What is the most effective way to prevent this?

A.Use a higher preference for BGP routes.
B.Configure route filters to prevent mutual redistribution.
C.Set a lower metric on OSPF routes.
D.Increase the OSPF cost on interfaces.
AnswerB

Route filters can block routes from being redistributed back into the originating protocol, breaking the loop.

Why this answer

Route filters prevent mutual redistribution, which is the root cause of routing loops. Options A, C, and D do not address the redistribution issue.

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25
MCQhard

A router receives two OSPF routes for 10.10.10.0/24: one intra-area with preference 10 and metric 1, and one external type 2 with preference 150 and metric 20. Which route is selected as active?

A.The external route because it is type 2
B.The intra-area route because it has a lower preference
C.The external route because it has a higher metric
D.The intra-area route because it has a lower metric
AnswerB

Preference 10 is lower than 150, so intra-area route is active.

Why this answer

The correct answer is D. Junos selects routes based on preference first. Intra-area OSPF has preference 10, while external OSPF has preference 150.

Since 10 < 150, the intra-area route is chosen regardless of metric. Options A, B, and C are incorrect because preference overrides metric and next-hop type.

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26
MCQhard

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

A.The static route has a high preference.
B.The outbound interface is not up.
C.The static route is not committed.
D.The next-hop address is not reachable in the routing table.
AnswerD

The show route command for 10.10.10.1 returns no output, indicating the next-hop is unknown.

Why this answer

Option A is correct because the static route's next-hop (10.10.10.1) is not present in the routing table. Option B is wrong because the preference is low (5). Option C is wrong because the interface is shown in the route entry, implying it is up.

Option D is wrong because the route is present, so it is committed.

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27
MCQhard

A network engineer is troubleshooting a BGP routing issue. The router receives a route to 172.16.0.0/16 from two BGP peers with different local preferences. The route from peer A has local preference 200, and from peer B has local preference 100. The router selects the route from peer A. What is the next step in BGP path selection if the local preferences were equal?

A.Compare the MED.
B.Compare the AS path length.
C.Compare the IGP metric to the next-hop.
D.Compare the origin code.
AnswerB

After local preference, BGP selects the path with the shortest AS path.

Why this answer

Option D is correct because after local preference, BGP compares AS path length. Options A, B, and C are compared later in the BGP path selection process.

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28
Drag & Dropmedium

Order the steps to configure firewall filters (ACLs) in Junos.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order

Why this order

Firewall filters are defined with terms (match conditions and actions) and applied to interfaces.

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29
MCQhard

Refer to the exhibit. The router has three static routes configured. Which route will be used to forward a packet destined to 172.16.1.100?

A.The default route (0.0.0.0/0)
B.The router will drop the packet.
C.The static route to 10.0.0.0/8
D.The static route to 172.16.0.0/16
AnswerD

The destination 172.16.1.100 is within the 172.16.0.0/16 network.

Why this answer

The router will use the most specific matching route for the destination 172.16.1.100. The static route to 172.16.0.0/16 has a prefix length of 16, which is more specific than the default route (0.0.0.0/0) and the route to 10.0.0.0/8 (which does not match the destination). Therefore, the route to 172.16.0.0/16 is selected based on the longest-prefix-match rule.

Exam trap

The trap here is that candidates often assume a default route will always be used as a catch-all, but they forget that a more specific static route (like 172.16.0.0/16) will take precedence over the default route for matching destinations.

How to eliminate wrong answers

Option A is wrong because the default route (0.0.0.0/0) is only used when no more specific route matches the destination; here, the 172.16.0.0/16 route is a better match. Option B is wrong because the router does not drop the packet; it has a matching route (172.16.0.0/16) and will forward the packet accordingly. Option C is wrong because the static route to 10.0.0.0/8 does not match the destination 172.16.1.100, as the destination falls outside the 10.0.0.0/8 range.

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30
Multi-Selecthard

Which THREE route types are considered protocol-independent in Junos?

Select 3 answers
A.BGP routes
B.Direct routes
C.Local routes
D.Static routes
E.OSPF routes
AnswersB, C, D

Direct routes are protocol-independent, derived from interface configuration.

Why this answer

Direct, local, and static routes are considered protocol-independent because they are not learned or installed by any dynamic routing protocol. Direct routes are automatically created for directly connected interfaces, local routes represent the interface's own IP address, and static routes are manually configured by an administrator. These routes exist in the routing table regardless of whether any routing protocol is running, hence the term 'protocol-independent'.

Exam trap

The trap here is that candidates often confuse 'protocol-independent' with 'routing protocol' and incorrectly assume that all routes in the routing table are protocol-dependent, forgetting that direct, local, and static routes are manually or automatically generated without a dynamic protocol's involvement.

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31
MCQhard

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

A.The BGP route has a higher AS path length than another route
B.The BGP route has been rejected by a policy
C.The BGP next-hop is unreachable
D.The BGP local preference is too high
AnswerC

If the next-hop is not reachable, the route is hidden.

Why this answer

A hidden route typically indicates that the next-hop is unreachable or unresolved. Option A is correct. Option B describes a route that is visible but not active.

Option C describes a route that may not be active but still visible. Option D is incorrect because hidden routes are still candidates.

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32
MCQmedium

A network has two equal-cost OSPF paths to 192.168.1.0/24. The engineer wants to enable per-flow load balancing. Which configuration element is required?

A.Configure per-packet load balancing under the interface
B.Add 'multipath' under 'routing-options' for OSPF
C.Define a load-balancing hash-key including Layer 4 information
D.Set a higher preference on one path to force ECMP
AnswerB

'multipath' enables ECMP, which allows multiple equal-cost routes to be used.

Why this answer

ECMP requires enabling the 'multipath' statement under routing-options for the protocol. Option A is correct. Option B is not a typical configuration; per-packet is not recommended.

Option C is incorrect because setting a higher preference would break ECMP. Option D is incorrect because the hash-key is optional and not required.

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33
Multi-Selectmedium

Which two static route options result in traffic being dropped at the router? (Choose two.)

Select 2 answers
A.install
B.reject
C.next-table
D.discard
E.resolve
AnswersB, D

Reject drops traffic and sends ICMP unreachable.

Why this answer

The correct answers are B and D. The 'reject' option drops traffic and sends ICMP unreachable. The 'discard' option drops traffic silently. 'Next-table' forwards to another table. 'Resolve' is used for recursive resolution. 'Install' is not a static route option; it's a flag.

So B and D are correct.

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34
MCQmedium

A network engineer is troubleshooting a connectivity issue between two directly connected routers, R1 and R2. Both routers have IP addresses configured on their respective interfaces, and the interfaces are up. However, 'ping 192.168.1.2 source 192.168.1.1' from R1 fails. The engineer checks the routing table on R1 and sees a static route to 0.0.0.0/0 via a different next-hop, but no route for the 192.168.1.0/24 network. What is the most likely cause?

A.The route to the directly connected network is missing from the routing table, possibly because the interface is not properly configured or the link is down.
B.The ARP cache is stale and needs to be cleared.
C.The interface is not configured with an IP address.
D.A security policy is blocking ICMP traffic between the two routers.
AnswerA

A directly connected route appears only when the interface is up and has an IP address. The missing route indicates an interface issue despite being 'up'.

Why this answer

Option C is correct because the directly connected network must be present in the routing table for communication; if there is no route to 192.168.1.0/24, the ping source address is not considered reachable or the destination is not in the routing table. Option A is incorrect because interface state is up, so 'show interfaces terse' would show the addresses. Option B is incorrect because ARP is not a routing table entry.

Option D is incorrect because a security policy is not relevant for directly connected interfaces unless zone configuration is wrong, but the issue is routing.

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35
MCQmedium

A network engineer configures a static route to 10.0.0.0/8 with a preference of 20. An OSPF internal route to 10.0.0.0/8 has a default preference of 10. Which route will be active in the routing table?

A.Both routes, because they have different protocols.
B.Neither, because of a conflict.
C.The OSPF route, because of lower preference.
D.The static route, because it is manually configured.
AnswerC

Lower preference (10) makes OSPF route preferred over static (20).

Why this answer

The OSPF route has a lower preference (10) than the static route (20), so OSPF is chosen. Option A is incorrect because preference is the deciding factor. Option C is false; only one active route per prefix.

Option D is incorrect.

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36
MCQmedium

Your Juniper router is running OSPF with multiple neighbors. You have a prefix 10.10.10.0/24 that is being learned via OSPF from two different routers: Router A with metric 30 and Router B with metric 20. The OSPF route from Router B is active. You want to ensure that traffic to 10.10.10.0/24 uses the path through Router A instead, even though it has a higher metric. You cannot change the OSPF metric on Router A. Which action should you take?

A.Use a routing policy to increase the preference of the OSPF route from Router B.
B.Increase the metric on Router B for that prefix.
C.Use a routing policy to reject the OSPF route from Router A.
D.Configure a static route to 10.10.10.0/24 pointing to Router A.
AnswerA

Increasing preference makes it less preferred, so the route from Router A (with lower preference) becomes active.

Why this answer

In JUNOS, route preference (administrative distance) determines which route is installed in the routing table when multiple protocols or sources provide the same prefix. By default, OSPF internal routes have a preference of 10. You can use a routing policy to increase the preference of the OSPF route from Router B (making it less preferred), which will cause the route from Router A (with its default preference of 10) to become active, even though its metric is higher.

This approach does not require changing the OSPF metric or removing the route from Router A.

Exam trap

The trap here is that candidates often confuse metric (cost) with preference (administrative distance) and think they must change the metric or reject routes, when in fact JUNOS allows preference manipulation via routing policies to influence route selection without altering the OSPF metric.

How to eliminate wrong answers

Option B is wrong because increasing the metric on Router B for that prefix would make the route from Router B even less attractive, but the goal is to prefer Router A; increasing Router B's metric would not help and might break other routing decisions. Option C is wrong because rejecting the OSPF route from Router A would remove the route entirely, but the question states the route from Router A is already not active; rejecting it would not make it active. Option D is wrong because configuring a static route to 10.10.10.0/24 pointing to Router A would install a static route with a default preference of 5, which is lower than OSPF's 10, making it active; however, this is not the best practice and does not leverage OSPF's dynamic capabilities, and the question asks for an action related to OSPF routes, not a static override.

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37
Multi-Selectmedium

Which two statements about static routes in Junos OS are correct?

Select 2 answers
A.A static route with a next-hop of 127.0.0.1 is an unreachable route.
B.Static routes have a default preference of 5.
C.A static route configured with a next-hop of an interface name (e.g., ge-0/0/0) uses Address Resolution Protocol (ARP) to resolve the next-hop MAC address.
D.A static route with a next-hop of 0.0.0.0 is a discard route.
E.Static routes can have a preference value of 0.
AnswersB, C

Correct: the default preference for static routes is 5.

Why this answer

Option A is correct: static routes have a default preference of 5. Option B is correct: when a static route uses an interface as the next-hop, the router uses ARP to resolve the MAC address of the next-hop. Option C is incorrect: a next-hop of 0.0.0.0 is used for a default route, not a discard route; a discard route uses the 'discard' keyword.

Option D is incorrect: static routes cannot have a preference of 0; preference 0 is reserved for directly connected routes. Option E is incorrect: 127.0.0.1 is a loopback address, but as a next-hop it would require the loopback interface to be specified and is not typically used for unreachable routes.

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38
MCQeasy

A router has a directly connected route to 10.10.10.0/24 on interface ge-0/0/0.0, a static route to the same prefix with next-hop 192.168.1.1, and an OSPF route to the same prefix. Which route is active in the routing table?

A.The static route
B.No route is active due to multiple routes
C.The OSPF route
D.The directly connected route
AnswerD

Direct routes have preference 0, which is the lowest possible, so they are always preferred.

Why this answer

The correct answer is A. Directly connected routes have a preference of 0, which is the lowest and therefore always preferred when the interface is up. Static routes have preference 5, OSPF internal has 10.

So the direct route wins. Options B, C, and D are incorrect because none can beat a direct route.

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39
Multi-Selecteasy

Which TWO statements about route preferences in Junos are correct?

Select 2 answers
A.The preference of a route cannot be changed.
B.Direct routes have a default preference of 0.
C.OSPF internal routes have a default preference of 10.
D.Static routes have a default preference of 10.
E.BGP routes have a default preference of 200.
AnswersB, C

Correct: Direct routes have preference 0.

Why this answer

Default route preferences: direct = 0, static = 5, OSPF internal = 10, BGP = 170. Preferences can be changed using routing policies.

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40
MCQmedium

Refer to the exhibit. How many static default routes are configured?

A.1
B.0
C.3
D.2
AnswerD

Two static routes for 0.0.0.0/0 with different preferences.

Why this answer

Option D is correct because the exhibit shows two static routes with a next-hop of 0.0.0.0, which are static default routes. In JUNOS, a static default route is defined by a destination prefix of 0.0.0.0/0 (or ::/0 for IPv6). The configuration lists two such routes, each with a different next-hop address, confirming two static default routes.

Exam trap

The trap here is that candidates may miscount the number of default routes by including non-default static routes (e.g., 10.0.0.0/8) or by overlooking that a default route must have a prefix length of /0, leading to an incorrect count.

How to eliminate wrong answers

Option A is wrong because it claims only one static default route is configured, but the exhibit clearly shows two entries with destination 0.0.0.0/0. Option B is wrong because it states zero static default routes are configured, ignoring the two explicit 0.0.0.0/0 routes present. Option C is wrong because it suggests three static default routes, but only two routes with destination 0.0.0.0/0 are shown; the third route listed has a different destination (e.g., 10.0.0.0/8) and is not a default route.

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41
MCQeasy

You are managing a small enterprise network with one Juniper router and two switches. The router connects to an ISP via ge-0/0/0 and to the internal network via ge-0/0/1. The internal network uses the 192.168.1.0/24 subnet. You need to configure a default route on the router to send all Internet-bound traffic to the ISP gateway at 203.0.113.1. You also want to ensure that internal hosts can reach the Internet. After configuring the default route, you test connectivity from a host on the internal network to an external website, but the ping fails. You verify that the host has an IP address of 192.168.1.100/24 and a default gateway of 192.168.1.1 (the router's internal interface). On the router, you run 'show route 0.0.0.0/0' and see the default route active. You also run 'ping 203.0.113.1' from the router and it succeeds. However, pinging from the host to the ISP gateway fails. What is the most likely cause?

A.DNS resolution is failing on the host.
B.The host's default gateway is incorrectly configured.
C.The default route is not active on the router.
D.Proxy ARP is not enabled on the router's internal interface.
AnswerD

Without proxy ARP, the router does not respond to ARP requests for the ISP gateway, so the host cannot resolve the next-hop MAC.

Why this answer

Option D is correct because the host's default gateway (192.168.1.1) is correctly configured, and the router has a working default route to the ISP gateway (203.0.113.1). However, when the host sends a ping to an external IP (e.g., the ISP gateway), the router receives the packet on ge-0/0/1 and routes it out ge-0/0/0. The reply from 203.0.113.1 arrives back at the router's ge-0/0/0, but the router does not have a route for the host's source IP (192.168.1.100) in its routing table (since it's directly connected to ge-0/0/1, but the router needs to send an ARP request for that IP on ge-0/0/1).

If Proxy ARP is not enabled on ge-0/0/1, the router will not respond to ARP requests for the host's IP, so the reply packet cannot be delivered to the host. Proxy ARP allows the router to answer ARP requests on behalf of hosts that are not on the same subnet, which is necessary here because the ISP gateway's reply is destined to 192.168.1.100, and the router must act as a proxy to forward that reply to the correct host.

Exam trap

The trap here is that candidates often assume the default route or host gateway is misconfigured, but the real issue is the router's inability to forward return traffic to the host due to missing Proxy ARP, which is a subtle Layer 2-to-Layer 3 interaction.

How to eliminate wrong answers

Option A is wrong because DNS resolution is not required for a ping to an IP address; the ping command uses the IP directly, so DNS failure would not cause the ping to fail. Option B is wrong because the host's default gateway is correctly set to 192.168.1.1, which is the router's internal interface IP; this is verified by the host having an IP of 192.168.1.100/24 and the router's ge-0/0/1 being on the same subnet. Option C is wrong because the 'show route 0.0.0.0/0' command confirmed the default route is active on the router, and the ping from the router to 203.0.113.1 succeeded, proving the route is functional.

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42
Multi-Selecthard

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

Select 2 answers
A.Next-hop reachability
B.Number of hops
C.Metric (or cost)
D.Prefix length
E.Preference value
AnswersC, E

Within the same protocol, lower metric is preferred; across protocols, preference is compared first.

Why this answer

Route preference and metric (or cost) are used to compare routes from different protocols or within the same protocol. Options A and B are correct. Option C is a condition for route to be considered, not for comparison.

Option D is used for longest prefix match, not preference. Option E is not a factor in JunOS route preference.

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43
MCQhard

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?

A.Configure the dynamic protocol to export the route with a metric of 1.
B.Configure a static route to 10.1.1.0/24 with next-hop 192.168.1.1 and preference 5.
C.Configure a filter to reject the dynamic route.
D.Configure a static route to 10.1.1.0/24 with next-hop 192.168.1.1 and preference 15.
AnswerB

Preference 5 is lower than most dynamic defaults, so static will be active.

Why this answer

Configure a static route with preference 5, which is lower than the default dynamic preferences (e.g., OSPF 10, BGP 170). This ensures the static route is preferred. Option B (preference 15) would be higher than OSPF, so static would not win.

Option C could work but is not the simplest. Option D does not affect route selection across protocols.

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44
Multi-Selecteasy

Which TWO statements about active routes in the Junos routing table are correct?

Select 2 answers
A.All routes in the routing table are active.
B.Multiple active routes can exist for the same prefix.
C.An active route is installed in the forwarding table.
D.An active route must have a valid next hop.
E.An active route is always preferred over a passive route.
AnswersC, D

Active routes are used for forwarding.

Why this answer

Option C is correct because an active route in Junos is one that is selected as the best route for a given prefix and is installed in the forwarding table (the FIB). The forwarding table is used by the Packet Forwarding Engine (PFE) to make actual forwarding decisions, so only active routes are placed there.

Exam trap

The trap here is that candidates often confuse 'active route' with 'all routes in the table' or think multiple active routes can coexist for the same prefix, but Junos strictly selects only one active route per prefix based on route preference.

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45
Multi-Selectmedium

Which TWO attributes are used by Junos to select the active route among multiple routes to the same destination?

Select 2 answers
A.Metric
B.Preference
C.Protocol type
D.Next hop address
E.AS path length
AnswersA, B

Lower metric is preferred when preference is equal.

Why this answer

Junos uses the route preference (also known as administrative distance) as the primary attribute to select the active route among multiple routes to the same destination. If multiple routes have the same preference, Junos then compares the metric (also called cost or protocol-specific metric) to break the tie. Preference is a local, configurable value that ranks the trustworthiness of the routing protocol source, while metric is a protocol-specific value (e.g., OSPF cost, RIP hop count) used within the same protocol.

Exam trap

The trap here is that candidates often confuse Junos's use of 'preference' with Cisco's 'administrative distance' and mistakenly think 'protocol type' or 'next hop address' are selection attributes, when in fact Junos uses preference and metric as the two standard tiebreakers for active route selection.

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46
MCQhard

A service provider operates a Juniper MX router that receives a default route from two different ISPs via EBGP. Both ISPs advertise 0.0.0.0/0 with the same local preference (100), same AS path length, and same metric. The network administrator wants to load balance outgoing traffic across both ISPs for redundancy and bandwidth utilization. After applying the configuration, the administrator checks the routing table and sees that only one default route is active, the one from ISP-A. The other route from ISP-B is present but not active. The administrator verifies that both routes have the same preference (170) and same BGP attributes. The ISP links are different: ISP-A is connected via interface ge-0/0/0.0 with next-hop 10.1.1.2, and ISP-B via interface ge-0/0/1.0 with next-hop 10.2.2.2. What is the most likely reason that both routes are not active and load-balanced?

A.The router has 'no-policy-statistics' enabled on the BGP sessions.
B.The BGP routes have different next-hop addresses.
C.The BGP routes are from different autonomous systems.
D.The router is configured with 'multipath multiple-as' under BGP.
AnswerC

Junos requires the 'multipath multiple-as' configuration to load balance routes from different ASes; otherwise, only the best path is installed.

Why this answer

The correct answer is C. By default, Junos BGP does not load balance routes from different autonomous systems. To enable multipath across different ASes, the 'multipath multiple-as' command must be configured under BGP.

Option A is irrelevant. Option B is not a cause because different next-hops can be load-balanced under multipath. Option D is the solution, not the cause.

Therefore, the most likely cause is that the routes are from different ASes.

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47
MCQeasy

You are a network engineer at a company that uses a pair of Juniper EX4300 switches in a virtual chassis (VC) configuration for the campus core. The VC is running OSPF with a single area and has multiple uplinks to an upstream router. The router is advertising a default route via OSPF. You want all inter-vlan traffic within the VC to be switched, but internet-bound traffic should be routed via the default route. You notice that some VLANs are not able to reach the internet while others can. All VLANs have a default gateway on the VC, which is the same IP (the VC's management IP). Users in the failing VLANs can ping the default gateway but cannot ping the upstream router's interface IP. What is the most likely cause?

A.The VC is configured as an OSPF area border router and is not creating a summary for the failing VLANs.
B.The VC's MAC address table is not learning the upstream router's MAC address on the correct VLAN.
C.The IRB interface for the failing VLANs does not have OSPF enabled, so the upstream router does not have a route to those subnets, and return traffic is dropped.
D.The default route from OSPF is not being installed because there is a static default route with lower preference.
AnswerC

For the upstream router to send return traffic, it must have a route to the VLAN subnet; if the VC does not advertise the subnet via OSPF, the router may use a default route but might send traffic to a different next-hop.

Why this answer

Option A is correct because if the failed VLANs are not included in the OSPF configuration on the VC, the VC may not advertise those networks, and the upstream router may not have a route back, causing asymmetric routing. Also, if OSPF is not enabled on the VLAN's IRB interface, the default route is not installed for that subnet. Option B is incorrect; the default route is learned via OSPF and is global.

Option C is incorrect; the VC's MAC address is not relevant. Option D is incorrect; OSPF does not require an area border.

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48
MCQeasy

You are a network engineer for a company that uses two Juniper routers, R1 and R2, connected via an Ethernet link. R1 and R2 are running OSPF in the same area, and R2 also has an eBGP session with a service provider to reach the internet. On R1, you have configured a static route to the subnet 172.16.10.0/24 with a next-hop of 192.168.1.2, which is the IP address of R2's interface facing R1. You have verified that the static route is configured correctly in the configuration, but traffic from R1 to 172.16.10.0/24 is not being forwarded. You check the routing table on R1 and see that the static route is present but marked as 'hidden'. You also notice that R1 has an OSPF-learned route to 192.168.1.0/30 (the link between R1 and R2) with a cost of 1. What is the most likely reason for the hidden static route?

A.Disable the eBGP session on R2 to remove the BGP routes from the routing table.
B.Increase the static route's preference to a lower value (e.g., 4).
C.Configure a more specific static route to 172.16.10.0/24 with a mask of /25.
D.Check if the next-hop IP 192.168.1.2 is reachable via the directly connected interface.
AnswerD

Correct: the next-hop unreachability is the most common cause of a hidden static route; verifying reachability (e.g., ping, ARP) will identify the issue.

Why this answer

A static route becomes hidden when the next-hop is unreachable. Even though R1 has an OSPF route to the subnet containing the next-hop (192.168.1.0/30), the router checks reachability at the IP level. In this scenario, the next-hop 192.168.1.2 is directly connected and should be reachable via the OSPF route.

However, the question states the static route is hidden, indicating the next-hop is not considered reachable. This can happen if there is a firewall filter or a security policy blocking ARP or if the interface is down. Option A is the most direct troubleshooting step.

Option B is incorrect because the default preference of 5 is already low; increasing it would make the route less preferred. Option C is incorrect as the route is already specific. Option D is incorrect: disabling BGP would not affect the static route's next-hop reachability.

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49
MCQhard

A static route to 10.0.0.0/8 has next-hop 192.168.1.1. The route is not installed in the routing table. Which condition must be met for the route to become active?

A.The static route must have a lower preference than any dynamic route to the same prefix.
B.The next-hop must have an ARP entry in the ARP table.
C.The next-hop 192.168.1.1 must be reachable via an active route (e.g., a direct or OSPF route).
D.The metric of the static route must be lower than that of any other route to the same prefix.
AnswerC

Indirect next-hops require an active route to the next-hop address for the static route to be installed.

Why this answer

The correct answer is C. For a static route with an indirect next-hop, the next-hop must be reachable via another active route. This is called recursive route resolution.

Option A is incorrect because static routes do not depend on an ARP entry directly; they require a route to the next-hop. Option B is incorrect because preference affects selection, not installation. Option D is incorrect because metric is not used by static routes for resolution.

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50
MCQmedium

A network engineer is managing a hub-and-spoke OSPF network for a retail company. The hub router (hub01) is at the data center with a loopback address 10.99.99.99. The spoke router (spoke01) is at a branch office and connects to hub01 via two links: a primary T1 link on interface ge-0/0/0.0 and a backup LTE link on interface lte-0/0/0.0. Both links are in area 0. Recently, the spoke router began sending traffic to the hub's loopback over the LTE link instead of the T1 link, causing higher latency and data charges. The engineer checks the routing table on spoke01 and sees that the route to 10.99.99.99/32 has two equal-cost next-hops: one via ge-0/0/0.0 and one via lte-0/0/0.0. The engineer wants to ensure that only the T1 link is used under normal conditions, with the LTE link as a backup. Which action should the engineer take to achieve this?

A.Decrease the OSPF cost on interface ge-0/0/0.0 to 1.
B.Configure a static route to 10.99.99.99/32 with next-hop referencing the T1 interface and a lower preference than OSPF.
C.Set the OSPF priority on ge-0/0/0.0 to 128 to influence the designated router election.
D.Increase the OSPF cost on interface lte-0/0/0.0 to a value higher than the cost on ge-0/0/0.0.
AnswerD

This makes the T1 path lower cost, so it will be the only active route. The LTE path becomes a backup if the T1 fails.

Why this answer

The correct answer is A. By increasing the OSPF cost on the LTE interface, the path via LTE becomes higher cost, making the T1 path the only active route (since ECMP will break). Option B may not work if the T1 cost is already at the minimum (1).

Option C uses a static route, which would override OSPF but is not best practice and could cause routing loops. Option D affects DR election, not route selection. Hence, A is the best course of action.

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51
Multi-Selecteasy

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

Select 2 answers
A.Route preference
B.Next-hop type
C.Number of hops
D.Metric
E.Route age
AnswersA, D

Lower preference is preferred; this is the primary selection criterion.

Why this answer

The correct answers are A and B. Junos first compares route preference; if equal, then metric is used. Next-hop type, route age, and number of hops are not standard tie-breakers.

Option C is not used. Option D (route age) might be used as a final tie-breaker? Actually Junos does use route age as a tie-breaker after metric? But in JNCIA, preference and metric are the primary factors. I'll stick with A and B.

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52
Matchingmedium

Match each Junos configuration hierarchy to its function.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts
Matches

Configures physical and logical interfaces

Configures routing protocols

Configures routing policies and prefix lists

Configures firewall, NAT, and IPsec

Configures system parameters like hostname and NTP

Why these pairings

These are top-level configuration hierarchies in Junos.

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53
MCQhard

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?

A.Increase the OSPF preference for 10.1.1.0/24 to 175
B.Add a static route for 10.1.1.0/24 with next-hop 10.2.2.2
C.Configure 'set protocol bgp group internal-mesh local-address 10.2.2.2' to set next-hop to self
D.Use route reflection to break the loop
AnswerA

A higher preference value makes OSPF less preferred than BGP, so the BGP route becomes active and the loop is resolved.

Why this answer

The loop occurs because the OSPF route (preference 10) is active, pointing a BGP next-hop that causes a recursive loop. By increasing the OSPF route's preference to 175 (higher than BGP's 170), the BGP route becomes active, and if the BGP next-hop is reachable via a non-looping path, the loop stops. Option A is correct.

Option B is incorrect because setting next-hop to self does not prevent the OSPF route from being used. Option C is incorrect because a static route would override BGP and would not be received via BGP. Option D is incorrect because route reflection does not address the preference conflict.

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54
MCQhard

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?

A.Both routes, if they are equal-cost.
B.The route with the higher preference value.
C.The OSPF route, because OSPF is a dynamic routing protocol.
D.The static route, because it has a lower preference value.
AnswerD

Static route preference 5 is lower than OSPF's 10.

Why this answer

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.

Exam trap

The trap here is that candidates often assume dynamic protocols like OSPF are always preferred over static routes, but Junos uses preference (administrative distance) where static routes have a lower default value than OSPF, making them more preferred.

How to eliminate wrong answers

Option A is wrong because Junos installs only the single best route (lowest preference) into the forwarding table; equal-cost multipath only applies when routes have the same preference and metric, which is not the case here. Option B is wrong because a higher preference value indicates a less preferred route; the route with the lower preference value is chosen. Option C is wrong because the decision is based on administrative distance (preference), not on whether the protocol is dynamic or static; OSPF has a higher preference (10) than a static route (5), so the static route wins.

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55
Multi-Selectmedium

Which THREE statements about static routes in Junos are correct?

Select 3 answers
A.Static routes have a default preference of 5.
B.You can configure multiple static routes to the same destination for load balancing.
C.The preference of a static route cannot be changed.
D.Static routes automatically update if the next hop becomes unreachable.
E.A static route can use a qualified next hop to specify a fallback.
AnswersA, B, E

Default preference for static routes is 5.

Why this answer

Static routes in Junos have a default preference of 5, which is lower (more preferred) than routes learned from most dynamic routing protocols like OSPF (preference 10) or IS-IS (preference 18). This default value ensures that static routes are preferred over dynamically learned routes unless explicitly overridden.

Exam trap

The trap here is that candidates often assume static route preference is immutable (like in some other vendors' implementations), but Junos allows preference modification, and they may also forget that static routes do not dynamically react to next-hop failures without additional configuration.

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56
MCQmedium

Your company recently acquired a small office that uses a Juniper MX router to connect to two ISPs for redundancy. The router has two uplinks: xe-0/0/0 to ISP-A (next-hop 10.0.0.1) and xe-0/0/1 to ISP-B (next-hop 10.0.1.1). The router receives a full BGP table from both ISPs. You want to prefer ISP-A for most traffic, but use ISP-B as a backup. You have configured BGP with local-preference 200 on routes from ISP-A and local-preference 100 on routes from ISP-B. After committing, you check the routing table and see that for some destinations, the route from ISP-B is active despite having lower local-preference. What is the most likely reason?

A.The local-preference is not applied to routes that are learned via eBGP; it only works for iBGP.
B.The router is not receiving the ISP-A routes for those specific prefixes; perhaps ISP-A's BGP session is missing or the prefix is not advertised.
C.The IGP metric to the next-hop from ISP-B is lower, causing the route to be preferred.
D.The MED value from ISP-A is higher than from ISP-B, overriding the local-preference.
AnswerB

If only ISP-B has the route, it will be active regardless of local-preference.

Why this answer

Option A is correct because BGP best path selection considers local-preference first, but if multiple routes have the same local-preference, other attributes like AS-path length are considered. Since both routes have different local-preference (200 vs 100), the one with 200 should be preferred. If the ISP-B route is active for some destinations, it indicates that the ISP-A route might not be received for those prefixes (e.g., partial BGP table).

Option B is incorrect; MED is compared only if the routes are from the same AS. Option C is incorrect; IGP metric is not compared in BGP best path selection until later steps, and local-preference is first. Option D is incorrect; the router does not ignore local-preference.

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57
Multi-Selecteasy

Which TWO statements are true about static routes in Junos?

Select 2 answers
A.Static routes have a default preference value of 10.
B.Static routes remain in the routing table even if the next hop is unreachable.
C.Static routes have a default preference value of 5.
D.Static routes require a routing protocol to be activated.
E.Static routes are automatically updated if the network topology changes.
AnswersB, C

Junos keeps static routes in the table; they are not removed automatically.

Why this answer

Static routes in Junos have a default preference of 5, not 10 (which is the default for OSPF internal routes). They remain in the routing table even if the next hop becomes unreachable because Junos uses a 'passive' route model; the route is only removed if explicitly deleted or if a better route is learned via a routing protocol. This behavior is controlled by the 'no-readvertise' and 'passive' attributes of static routes.

Exam trap

The trap here is that Cisco candidates often assume static routes have a default preference of 1 (Cisco's administrative distance for static routes) or 10 (OSPF), but Junos uses 5, and they also mistakenly think static routes are removed when the next hop is unreachable, which is true in Cisco IOS but not in Junos without explicit configuration.

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58
MCQeasy

You are managing a small branch office with a Juniper SRX firewall that connects to the internet via a single ISP. The internal network uses 192.168.1.0/24. You need to configure a default route so that all internet-bound traffic goes to the ISP's next-hop 203.0.113.1. The SRX has two interfaces: ge-0/0/0 (untrust) with IP 203.0.113.2/30 and ge-0/0/1 (trust) with IP 192.168.1.1/24. You add the following configuration: 'set routing-options static route 0.0.0.0/0 next-hop 203.0.113.1'. After committing, devices on the trust network can ping the internet (e.g., 8.8.8.8) successfully. However, users report that they cannot access a specific public website hosted at 198.51.100.10. You verify that the SRX can reach that IP via ping and traceroute. What is the most likely cause of this issue?

A.The SRX's source IP for outbound traffic is incorrect; it should use the untrust interface IP but is using the trust IP.
B.The return traffic from the website is not reaching the SRX, possibly due to asymmetric routing or the website's firewall blocking the SRX's source IP.
C.The default route is missing; the ISP must be configured as a static route.
D.There is a more specific static route to 198.51.100.0/24 with a different next-hop causing traffic to be sent elsewhere.
AnswerB

Since SRX can ping, the forward path works; return path or the destination server's security may be blocking traffic.

Why this answer

Option C is correct because the default route is working, but the specific path may have a problem like a routing loop or black hole. Since the SRX can reach the IP, the issue is likely on the return path or the destination is filtering traffic. Option A is incorrect because the default route is present and working for other destinations.

Option B is incorrect because there is no evidence of a more specific route. Option D is incorrect because the SRX can ping, so source IP is not the issue.

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59
MCQmedium

You are configuring a Juniper MX router to act as a BGP route reflector for your ISP network. The router has several iBGP peers, including clients and non-clients. You have configured the route-reflector-cluster-id and set the clients. After the configuration, you notice that some prefixes are not being reflected to a specific client router. The client has a valid BGP session to the route reflector and can see other prefixes. You check the BGP routing table on the route reflector and see that the missing prefixes are present but have the 'non-routable' flag. The route reflector's BGP table shows the prefix with a next-hop that is reachable via an IGP route. What is the most likely cause?

A.The next-hop for the missing prefixes is not reachable via the IGP on the route reflector; the route reflector needs a route to the next-hop to advertise the prefix.
B.The route-reflector-cluster-id is set incorrectly, causing the route reflector to drop the route to prevent loops.
C.The ORIGINATOR_ID attribute from a previous route reflector is causing the route to be suppressed.
D.The route reflector is using the next-hop-self option and cannot resolve its own IP as a next-hop.
AnswerA

BGP requires the next-hop to be reachable for the route to be considered valid and eligible for advertisement.

Why this answer

Option B is correct because BGP route reflection only sends routes that are valid (i.e., routable). The 'non-routable' flag indicates that the next-hop is not reachable via the IGP (or any route) in the route reflector's routing table. Even if the next-hop is reachable from the client, the route reflector must have a route to the next-hop to advertise the prefix to clients.

Option A is incorrect; cluster-id is used to detect loops, not to suppress routes. Option C is incorrect; the ORIGINATOR_ID attribute is set by the route reflector, but it does not suppress the route. Option D is incorrect; the route reflector does not modify the next-hop by default; the client must have a route to the next-hop.

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60
MCQeasy

Which Junos command displays the route to a specific IP address, including the active route and any backup routes?

A.show route 192.168.1.1
B.show route protocol
C.show route active
D.show route table
AnswerA

Displays all routes to that IP address.

Why this answer

Option A is correct because the 'show route 192.168.1.1' command in Junos displays all routes in the routing table that match the specified destination, including the active route (marked with '>') and any backup routes (marked with a space). This command provides a comprehensive view of the forwarding table entries for that prefix, which is essential for understanding both primary and failover paths.

Exam trap

The trap here is that candidates familiar with Cisco IOS might expect 'show ip route <ip>' to show only the best route, but in Junos, the same command reveals all routes, including backups, which can lead to confusion if one assumes only the active route is displayed.

How to eliminate wrong answers

Option B is wrong because 'show route protocol' filters routes by a specific routing protocol (e.g., static, OSPF, BGP) and does not show routes to a specific IP address with active and backup routes. Option C is wrong because 'show route active' displays only the active routes in the routing table, omitting any backup or inactive routes. Option D is wrong because 'show route table' displays the entire routing table for a specific table (e.g., inet.0) without filtering to a particular destination, so it does not isolate the route to 192.168.1.1 or highlight active versus backup routes.

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61
MCQeasy

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?

A.Configure a higher metric on the static route.
B.Configure a preference of 0 on the static route.
C.Configure the next-hop as an IP address.
D.Configure the next-hop as the interface name.
AnswerD

Using an interface as the next-hop ties the route to the interface being up; if the interface goes down, the route is removed.

Why this answer

Option D is correct because 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.

Exam trap

The trap here is that Cisco engineers often assume that specifying a next-hop IP address is the only valid way to configure a static route, but in Junos, using the interface name directly ties the route to the interface's state, which is the key to automatic removal upon interface failure.

How to eliminate wrong answers

Option A is wrong because configuring a higher metric on a static route does not cause it to be removed when an interface fails; metric (or cost) is used for route selection among multiple routes to the same destination, not for interface-based withdrawal. Option B is wrong because setting a preference of 0 makes the static route the most preferred route (lowest preference value), but it does not tie the route to the interface's operational state; the route remains even if the interface fails. Option C is wrong because configuring the next-hop as an IP address creates a static route that is not automatically removed when the directly connected interface fails; the route persists in the routing table unless the next-hop becomes unreachable via any interface, which may not happen if an alternate path exists.

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62
Multi-Selecthard

Which three characteristics are true for OSPF? (Choose three.)

Select 3 answers
A.Uses the Bellman-Ford algorithm
B.Supports VLSM (Variable Length Subnet Masks)
C.Uses cost as the metric
D.Uses the SPF (Shortest Path First) algorithm
E.Is classful and does not support VLSM
AnswersB, C, D

OSPF is a classless protocol and supports VLSM.

Why this answer

The correct answers are A, C, and E. OSPF uses the Dijkstra SPF algorithm, supports VLSM/CIDR, and uses cost as its metric. It does not use Bellman-Ford (that's RIP).

It is classless, not classful. So A, C, E are correct.

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63
MCQhard

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

A.The BGP next-hop is unreachable
B.The route has a lower local preference
C.The route has a longer AS path
D.The route has a higher MED value
AnswerA

Hidden routes often result from an unreachable next-hop.

Why this answer

A hidden BGP route typically indicates that the next-hop is unreachable. Option A is correct. Option B is incorrect because localpref affects best path selection but does not cause hidden state.

Option C is incorrect because AS path length is considered but does not hide the route. Option D is incorrect because MED is 0, same as others.

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64
MCQmedium

An organization has two ISPs and wants to load-balance traffic equally across both links for all outbound traffic. Which routing configuration approach should be used?

A.Configure two static default routes with different metric values.
B.Configure policy-based routing to match all traffic and forward to both ISPs.
C.Configure two static default routes with equal metric values and enable ECMP.
D.Establish BGP sessions with both ISPs and rely on BGP path selection.
AnswerC

ECMP allows load balancing across equal-cost routes.

Why this answer

Option C is correct because configuring two static default routes with equal metric values and enabling Equal-Cost Multi-Path (ECMP) allows the Juniper device to load-balance outbound traffic equally across both ISP links. ECMP uses per-flow or per-packet load balancing based on the hash of source/destination IP addresses and ports, ensuring traffic is distributed evenly without relying on dynamic routing protocols.

Exam trap

The trap here is that candidates often confuse metric (cost) with preference (administrative distance) in Junos, assuming that different metric values still allow load balancing, whereas Junos requires equal metric values for ECMP to activate.

How to eliminate wrong answers

Option A is wrong because configuring two static default routes with different metric values results in only the route with the lower metric being active in the routing table, providing failover but not load balancing. Option B is wrong because policy-based routing (PBR) can forward traffic based on match criteria, but it does not inherently load-balance equally across two links without additional configuration like filter-based forwarding and per-packet load balancing, which is not the standard approach for simple equal load sharing. Option D is wrong because establishing BGP sessions with both ISPs and relying on BGP path selection does not guarantee equal load balancing; BGP selects only the best path based on attributes like local preference and AS path length, and additional configuration (e.g., multipath) is required to enable ECMP for BGP routes.

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65
MCQmedium

Refer to the exhibit. The router has a default static route and a static route to 10.0.0.0/24. An engineer updates the next-hop for the default route from 192.168.1.1 to 192.168.1.2. Which command should the engineer use to verify that the change is active?

A.show route 192.168.1.2
B.ping 192.168.1.2
C.show route 0.0.0.0/0
D.show route protocol static
AnswerC

This shows the active default route and its next-hop.

Why this answer

Option C is correct because the command 'show route 0.0.0.0/0' displays the routing table entry for the default route, including its next-hop address. After changing the next-hop from 192.168.1.1 to 192.168.1.2, this command confirms the active route has the updated next-hop. It directly verifies the specific prefix that was modified.

Exam trap

The trap here is that candidates often choose 'show route protocol static' thinking it shows all static routes, but they fail to realize it does not isolate the specific prefix changed, and the engineer needs to confirm the next-hop for 0.0.0.0/0, not just any static route.

How to eliminate wrong answers

Option A is wrong because 'show route 192.168.1.2' shows routes to that specific host address, not the default route; it would only confirm reachability to the next-hop, not the change to the default route. Option B is wrong because 'ping 192.168.1.2' tests IP connectivity to the next-hop address but does not verify that the default route in the routing table has been updated; the ping could succeed even if the route change failed. Option D is wrong because 'show route protocol static' displays all static routes, including both the default route and the route to 10.0.0.0/24, but it does not focus on the specific prefix 0.0.0.0/0; the engineer needs to confirm the change for that exact prefix, not all static routes.

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66
MCQhard

Your company operates a dual-homed network with two Juniper MX routers (R1 and R2) each connected to a different ISP. R1 uses BGP to receive a default route from ISP-A (preference 170), and R2 uses BGP to receive a default route from ISP-B (preference 170). Additionally, both routers have a static default route pointing to a local next-hop (192.0.2.1) with preference 5 for backup. R1 and R2 are connected via an internal link (10.0.0.0/30) and run OSPF to exchange internal routes. You notice that traffic from internal hosts is always exiting via R1's ISP-A link, even when R1's BGP session to ISP-A goes down. The OSPF routes are preferred. You want traffic to fail over to R2's ISP-B link when R1 loses its BGP default. Which configuration change should you make?

A.Increase the preference of the BGP default routes to 180 so that the static default is always preferred.
B.Configure a routing policy on R2 to reject the default route from ISP-B, forcing all traffic through R1.
C.Remove the static default route and rely on OSPF to propagate a default route from the router with the active BGP session.
D.Configure the static default route with a preference of 180 so that the BGP default routes (pref 170) are preferred when available.
AnswerD

This ensures BGP default is used when up, and OSPF routes to R2's default become active when R1's BGP is down.

Why this answer

Option D is correct because the static default route currently has a preference of 5, making it preferred over the BGP default (preference 170) even when the BGP route is available. By raising the static default's preference to 180 (higher than BGP's 170), the BGP default will be chosen when present, and the static default will only be used as a backup when BGP is unavailable. This ensures traffic fails over to R2's ISP-B link when R1 loses its BGP default, as OSPF will propagate the default from R2.

Exam trap

The trap here is that candidates often assume static routes with a lower preference are always better, but the question requires the static route to act as a backup, so it must have a higher preference than the BGP route to be less preferred when the BGP route is available.

How to eliminate wrong answers

Option A is wrong because increasing the BGP default preference to 180 would make it less preferred than the static default (preference 5), causing the static route to always be used, which does not solve the failover issue. Option B is wrong because rejecting the default route from ISP-B on R2 would prevent R2 from having any default route, breaking failover entirely and not addressing the preference problem on R1. Option C is wrong because removing the static default route would leave no backup path; OSPF does not automatically propagate a default route unless explicitly configured with a default-information originate statement, and even then, the OSPF default would have a preference of 10 (or 150 for external routes), which could still be preferred over BGP's 170, potentially causing the same issue.

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67
MCQhard

A router is running OSPF and iBGP. Both protocols learn a route to 10.0.0.0/8. The OSPF route is in the routing table with a preference of 10, and the iBGP route has a preference of 170. Which event would cause the iBGP route to become active?

A.The OSPF route is withdrawn.
B.Both A and C.
C.The iBGP route's metric is lower.
D.The OSPF route's preference is changed to 180.
AnswerB

Either withdrawing the OSPF route or increasing its preference above 170 allows the iBGP route to become active.

Why this answer

If the OSPF route is withdrawn, the iBGP route becomes active. Also, if the OSPF preference is increased above 170, iBGP wins. So both A and C are valid.

Option B does not apply because metric is not compared when preferences differ.

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68
MCQhard

Refer to the exhibit. Which route is active for the 192.168.1.0/24 prefix?

A.Both routes are active.
B.The static route because it has a lower preference.
C.Neither route is active.
D.The OSPF route because it is marked with an asterisk.
AnswerD

The '*' indicates the active route.

Why this answer

In JUNOS, the active route for a prefix is determined by the route preference (administrative distance). OSPF has a default preference of 10, while a static route has a default preference of 5. However, the exhibit shows the OSPF route with an asterisk (*), which in JUNOS indicates the active route in the routing table.

Since the OSPF route is marked with an asterisk, it is the active route, and the static route is a backup. Option D is correct because the asterisk signifies the active route, and OSPF's preference is higher (less preferred) than the static route's preference, but the asterisk overrides that assumption in this context.

Exam trap

The trap here is that candidates often assume a static route always wins over OSPF due to its lower preference, but they overlook that the asterisk in JUNOS output directly indicates the active route, and the static route may be inactive due to next-hop unreachability or other validation failures.

How to eliminate wrong answers

Option A is wrong because both routes cannot be active for the same prefix; JUNOS selects only one active route based on the lowest preference value. Option B is wrong because although a static route has a lower preference (5) than OSPF (10), the exhibit shows the OSPF route with an asterisk, indicating it is the active route; this means the static route is not active despite its lower preference, possibly due to the static route being configured with a next-hop that is unreachable or the route being inactive for another reason. Option C is wrong because the OSPF route is marked with an asterisk, which explicitly indicates it is active in the routing table.

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69
MCQeasy

Which JunOS command displays the active route for a specific destination along with the outgoing interface?

A.show route 10.0.0.1 active-path
B.show route 10.0.0.1 exact
C.show route 10.0.0.1 protocol static
D.show route 10.0.0.1 table inet.0
AnswerB

This command shows the active route with next-hop and interface.

Why this answer

The 'show route <prefix> exact' command displays the active route including the next-hop and interface. Option C is correct. Option A is not a valid command.

Option B shows all routes for that prefix, not just the active one. Option D shows only static routes.

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70
MCQeasy

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

A.The route is from the kernel.
B.The route was manually configured.
C.The route is a default route generated by the router.
D.The route was learned from a routing protocol.
AnswerB

The 'user' type indicates the route was configured by an administrator, typically as a static route.

Why this answer

Option B is correct because 'user' in the forwarding table indicates a manually configured route (e.g., static). Option A is wrong because protocol-learned routes show 'other' or specific protocol. Option C is wrong because default routes generated by the router (e.g., through router advertisement) would not show as 'user'.

Option D is wrong because kernel routes show as 'kern'.

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71
MCQhard

Refer to the exhibit. What is the most likely cause of this BGP route being hidden?

A.The route has a higher preference than another route.
B.The BGP session to 10.0.0.2 is down.
C.The prefix 10.1.1.0/24 is filtered by an import policy.
D.The next-hop 192.168.100.1 is not reachable via any active route.
AnswerD

The reason given is 'next hop unreachable', so the next-hop is not reachable.

Why this answer

The exhibit shows the route is hidden with the reason 'next hop unreachable'. This means the next-hop IP 192.168.100.1 is not reachable via any active route in the routing table.

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72
MCQmedium

Refer to the exhibit. How many active routes exist for 10.1.1.0/24?

A.1
B.2
C.0
D.3
AnswerA

Only the direct route is active, indicated by the asterisk.

Why this answer

Only one route is active (marked with '*'). The other routes are alternative routes. Option A is correct.

Option B counts all routes. Option C overcounts. Option D is incorrect because there is an active route.

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73
MCQhard

A router has two ISIS adjacencies to the same router, both with equal metrics. The router installs both routes in the routing table and performs load balancing. The network team wants to verify that both next-hops are being used for a particular destination. Which command provides this information?

A.`show route 10.0.0.0/24 extensive`
B.`show route forwarding-table destination 10.0.0.0/24`
C.`show route protocol isis`
D.`show route 10.0.0.0/24 detail`
AnswerB

This command displays the forwarding table, which shows the actual next-hops used for forwarding, including load-balanced paths.

Why this answer

Option A is correct because `show route forwarding-table destination` shows the actual next-hops used in the forwarding plane, including load-balanced paths. Option B is wrong because `show route` with detail may show multiple next-hops but not the hardware forwarding decision. Option C is wrong because it shows all ISIS routes, not specific next-hop usage.

Option D is wrong because extensive output still shows routing table, not forwarding table.

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74
MCQeasy

A network administrator configures a static route on a Juniper device: `set routing-options static route 192.168.100.0/24 next-hop 10.0.0.1`. The administrator verifies the route is present in the routing table but notices it is not active. What is the most likely cause?

A.The route is not committed.
B.The next-hop address 10.0.0.1 is not reachable.
C.The preference of the static route is higher than 15.
D.The destination prefix is already learned via OSPF with a lower metric.
AnswerB

If the next-hop is not in the routing table, the static route is not active.

Why this answer

A static route becomes active only if the next-hop address is reachable via a directly connected or active route in the routing table. Since the administrator verified the route is present but not active, the most likely cause is that the next-hop 10.0.0.1 is not reachable (e.g., no ARP resolution or no interface with that subnet). Junos marks such routes as hidden or inactive until the next hop is reachable.

Exam trap

The trap here is that candidates often assume a static route is always active once configured and committed, overlooking Junos's requirement that the next-hop must be reachable via an active directly connected route for the route to be installed as active.

How to eliminate wrong answers

Option A is wrong because the route is already present in the routing table, which means it has been committed; an uncommitted route would not appear at all. Option B is the correct answer as explained. Option C is wrong because the default preference for static routes in Junos is 5, which is lower than 15, and a higher preference (worse) would not prevent activation—it would only affect route selection among multiple routes to the same prefix.

Option D is wrong because OSPF routes have a default preference of 10 (internal) or 150 (external), and a static route with preference 5 would be preferred over OSPF; moreover, the question states the route is not active, not that it is not preferred.

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75
MCQhard

An engineer is configuring multiple static routes to the same destination for redundancy. The primary link uses 192.168.1.1 and the backup uses 192.168.2.1. They want the backup to be used only when the primary next-hop is unreachable. Which configuration is correct?

A.Configure the primary with a lower preference and the backup with a higher preference.
B.Configure the primary with a higher preference and the backup with a lower preference.
C.Configure two static routes with equal preferences; the active route will be chosen based on next-hop IP.
D.Configure the routes with the same preference but use a policy to set metric.
AnswerA

Lower preference is more preferred; when primary fails, backup takes over.

Why this answer

Configure the primary with a lower preference and the backup with a higher preference. When the primary is reachable, it is preferred due to lower preference. If it fails, the backup with higher preference becomes active.

Option A would not provide deterministic failover. Option C would make backup primary. Option D is not applicable.

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