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CCNA Protocol Independent Routing Questions

37 questions · Protocol Independent Routing topic · All types, answers revealed

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1
Multi-Selecthard

When configuring a routing instance of type 'virtual-router', which THREE characteristics apply? (Choose three)

Select 3 answers
A.It requires MPLS label distribution protocols to function.
B.Interfaces can be assigned directly to the virtual-router instance.
C.It supports dynamic interior routing protocols like OSPF and IS-IS.
D.Route leaking between virtual-router and inet.0 is strictly prohibited by Junos architecture.
E.It maintains independent routing tables separate from inet.0.
AnswersB, C, E

Physical or logical interfaces are bound to the virtual-router instance under its interface stanza, so traffic entering them is resolved against that instance's tables. This satisfies the stem's requirement, unlike other instance types that cannot own interfaces directly.

Why this answer

Option B is correct because a virtual-router routing instance in Junos is a true separate routing domain, so you assign physical or logical interfaces directly to it (for example, with 'set routing-instances <name> interface ge-0/0/0.0'), and those interfaces then use the instance's own routing table. Option C is correct because a virtual-router instance runs its own routing protocol process and can run dynamic IGPs such as OSPF and IS-IS within that instance, independently of the master instance. Option E is correct because the defining feature of a virtual-router instance is that it maintains its own independent routing table (named <instance-name>.inet.0) that is separate from the main inet.0 table.

Option A is not required, since a virtual-router instance is a pure Layer 3 routing separation and does not need MPLS label distribution protocols such as LDP or RSVP to function. Option D is false because Junos does not strictly prohibit route leaking between a virtual-router instance and inet.0; routes can be exchanged using rib-groups or instance-import/instance-export policies, so the statement is technically inaccurate.

Exam trap

JNCIS-ENT often tests the distinction between virtual-router and VRF instances; candidates incorrectly assume virtual-router requires MPLS or that route leaking is impossible.

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2
MCQmedium

You need to ensure that traffic entering interface ge-0/0/1 is forced into a specific forwarding routing instance named 'corp-fwd', regardless of the destination IP address in the packet header. Which configuration steps must you perform?

A.Create a forwarding instance, write a firewall filter with 'then routing-instance corp-fwd', and apply the filter as input on ge-0/0/1.
B.Create a virtual-router instance and apply a static default route pointing to ge-0/0/1.
C.Configure a routing policy with 'then export corp-fwd' and apply it under protocols.
D.Enable proxy-ARP on ge-0/0/1 and assign the corp-fwd routing instance to the physical port.
AnswerA

A firewall filter with the `then routing-instance corp-fwd` action performs policy-based routing, redirecting matched packets into the named forwarding instance before the normal destination lookup occurs. Applying it as an input filter on ge-0/0/1 satisfies the stem's requirement to force all ingress traffic into corp-fwd regardless of destination IP.

Why this answer

To force traffic from an interface into a specific forwarding routing instance regardless of destination, you create a forwarding instance (type 'forwarding'), define a firewall filter with the action 'then routing-instance corp-fwd', and apply that filter as an input filter on ge-0/0/1. This is the standard Junos method for policy-based routing into a forwarding instance, often used for service chaining or VRF selection.

Exam trap

JNCIS-ENT often tests the difference between forwarding instances and virtual-router instances — candidates confuse the two and pick answers involving virtual routers or routing policies, which do not achieve filter-based forwarding.

How to eliminate wrong answers

Option B is wrong because a virtual-router instance with a static default route pointing to ge-0/0/1 does not force ingress traffic into that instance — it only affects egress routing decisions within the instance. Option C is wrong because routing policies with 'then export' are used for route export between protocols or instances, not for classifying ingress traffic into a routing instance. Option D is wrong because proxy-ARP and assigning a routing instance to a physical port are not valid mechanisms for per-interface traffic steering — routing instances are associated with interfaces via configuration, but not in the way described, and proxy-ARP is unrelated.

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3
MCQhard

You have configured a qualified next-hop for a static route to 10.1.1.0/24 with a primary next-hop of 192.168.1.1 and a qualified next-hop of 192.168.1.2. Both next-hops are reachable. Under what condition will the qualified next-hop be used?

A.When the primary next-hop is reachable but the interface is congested.
B.When the primary next-hop fails or is unreachable.
C.When the primary next-hop is reachable and the qualified next-hop has a lower metric.
D.When the primary next-hop is reachable but has a higher preference.
AnswerB

A qualified next-hop serves as a backup path. It is only used when the primary next-hop becomes unreachable, as determined by the routing table's next-hop resolution. This provides redundancy without requiring multiple static routes. The qualified next-hop remains inactive until the primary fails.

Why this answer

A qualified next-hop provides a backup path for a static route. It is only installed in the forwarding table when the primary next-hop becomes unreachable. This allows for redundancy without configuring multiple static routes with different preferences.

The primary next-hop is always preferred when it is reachable.

Exam trap

The trap here is thinking that qualified next-hops are chosen based on preference or metric, when they are purely backup next-hops activated only on primary failure.

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4
MCQeasy

An engineer needs to configure a static IPv4 route on a Juniper Networks MX Series router pointing traffic destined for 192.168.100.0/24 to next-hop 10.0.0.1. Which configuration accomplishes this task?

A.set routing-instances default static route 192.168.100.0/24 next-hop 10.0.0.1
B.set protocols static route 192.168.100.0/24 next-hop 10.0.0.1
C.set interfaces fxp0 unit 0 family inet static-route 192.168.100.0/24 next-hop 10.0.0.1
D.set routing-options static route 192.168.100.0/24 next-hop 10.0.0.1
AnswerD

The `routing-options static route` hierarchy defines IPv4 static routes in Junos, with `next-hop 10.0.0.1` satisfying the stem's requirement to forward 192.168.100.0/24 traffic to that gateway. This syntax is valid on MX Series routers and installs the route into the inet.0 table, matching the destination prefix and next-hop exactly as specified.

Why this answer

In Junos, static routes are configured under the [edit routing-options] hierarchy, not under protocols or interfaces. The correct syntax is 'set routing-options static route <prefix> next-hop <address>', which installs the route into the inet.0 routing table for IPv4. This is the standard, documented method for defining a static IPv4 route on any Juniper device, including MX Series routers.

Exam trap

JNCIS-ENT often tests hierarchy memorization — candidates confuse 'protocols' (used for routing protocols like OSPF, BGP, IS-IS) with 'routing-options' (used for static routes, preferences, and router-level settings).

How to eliminate wrong answers

Option A is wrong because 'routing-instances default static route' is not valid Junos syntax — static routes are not configured under a routing-instance named 'default' in that manner, and 'default' is not a user-defined routing instance. Option B is wrong because 'protocols static' does not exist in Junos; static routes live under 'routing-options', not 'protocols'. Option C is wrong because static routes cannot be configured under an interface's 'family inet' stanza — that hierarchy is for interface addressing and related interface-level parameters, not route entries.

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5
Multi-Selectmedium

An engineer is configuring a static route with multiple qualified next hops to provide load balancing and redundancy. Which TWO statements are true regarding qualified next hops in Junos? (Choose two.)

Select 2 answers
A.Qualified next hops can have different preferences, and the one with the lowest preference is preferred.
B.Qualified next hops can only be used with IPv6 routes.
C.Qualified next hops can be used to load-balance traffic across multiple next hops when they have the same preference.
D.Qualified next hops automatically create a condition that must be met for the route to be active.
E.Qualified next hops must be directly connected to the router.
AnswersA, C

Qualified next hops allow you to assign a preference value to each next hop. The next hop with the lowest preference value is preferred and installed in the routing table. If that next hop becomes unreachable, the next hop with the next lowest preference is used. This provides backup path functionality.

Why this answer

Qualified next hops allow multiple next hops with preferences. They can be used for backup (different preferences) or load balancing (same preference). They are not limited to directly connected next hops and work for both IPv4 and IPv6.

Conditions are separate and must be explicitly configured.

Exam trap

The trap here is confusing qualified next hops with conditions, or assuming they are limited to directly connected next hops.

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6
MCQmedium

You need to configure filter-based forwarding (FBF) to route traffic from a specific subnet (192.168.1.0/24) through an alternate next-hop gateway. Which components are required to implement this successfully?

A.A static route pointing to the alternate gateway with a preference of 1.
B.A firewall filter with a routing-instance action, a custom routing instance, and application of the filter to the ingress interface.
C.An export routing policy with a load-balance action applied globally.
D.A firewall filter with a routing-instance action, a custom routing instance, and application of the filter to the egress interface.
AnswerB

Filter-based forwarding requires exactly these three elements: a stateless firewall filter matching the source subnet, a routing-instance action redirecting matched traffic, and filter application on the ingress interface. The custom routing instance holds the alternate next-hop, satisfying the requirement to divert 192.168.1.0/24 away from the default forwarding table.

Why this answer

Filter-based forwarding in Junos requires three elements working together: a stateless firewall filter that matches the traffic and applies a 'routing-instance' action, a custom routing instance (typically type forwarding) containing the alternate next-hop route, and the filter applied as an input filter on the ingress interface where the traffic arrives. The routing-instance action causes matched packets to be looked up in that instance's table instead of the main inet.0 table.

Exam trap

The trap is the direction of filter application — candidates who have only seen firewall filters as security tools often assume egress application, but FBF must intercept traffic before the forwarding lookup, i.e., on ingress.

How to eliminate wrong answers

Option A is wrong because a static route with preference 1 in the main table would affect all traffic to that destination, not selectively redirect the 192.168.1.0/24 subnet, and preference alone provides no match criteria. Option C is wrong because an export policy with load-balance has nothing to do with FBF — export policies control what routes are advertised into a protocol, not how transit packets are forwarded. Option D is wrong because applying the filter to the egress interface is too late: the forwarding decision has already been made using the main table, so the routing-instance action would never take effect.

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7
MCQeasy

You are configuring a virtual router routing instance on a Juniper device to isolate traffic for a specific department. Which routing-instance type should you select?

A.l2vpn
B.forwarding
C.no-forwarding
D.virtual-router
AnswerD

A virtual-router instance maintains its own independent routing table and protocol instances, giving the department full Layer 3 isolation from the master instance. This satisfies the requirement to separate that department's traffic without the overlapping-address limitations of other instance types.

Why this answer

A virtual-router routing instance creates a separate routing table (RIBs) and forwarding table (FIBs) for the instance, effectively giving the department its own logical router with independent interfaces, routing protocols, and policies. This is the correct type when you need full Layer 3 isolation with separate routing domains on the same physical device.

Exam trap

The trap here is confusing 'virtual-router' with 'vrf' — both provide Layer 3 isolation, but virtual-router is used for non-MPLS logical router separation while vrf is tied to MPLS L3VPN with route distinguishers and route targets.

How to eliminate wrong answers

Option A is wrong because l2vpn is used for Layer 2 VPN services (VPLS, VPWS) that bridge Ethernet frames across MPLS, not for isolating a department's Layer 3 traffic. Option B is wrong because a forwarding routing instance only creates a separate forwarding table for filter-based forwarding (FBF) — it does not run its own routing protocols or create a full routing table. Option C is wrong because no-forwarding is used for management-only instances that don't forward traffic at all, such as for out-of-band management or route reflection.

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8
MCQmedium

You are configuring Filter-Based Forwarding (FBF) on an interface. You apply a firewall filter that matches specific source addresses and uses 'then routing-instance' as an action. What must be configured in that target routing instance to ensure return traffic is handled correctly?

A.A default route pointing back to the core gateway within that routing instance's routing table.
B.A static ARP entry for every device on the network.
C.An RSVP LSP bridging the source and destination instances.
D.A BGP peering session with the loopback address.
AnswerA

Filter-based forwarding steers matched traffic into a separate routing instance, which by default has no path back to the core. Installing a default route (0.0.0.0/0) inside that instance's table ensures return traffic reaches the core gateway rather than being dropped.

Why this answer

When using Filter-Based Forwarding (FBF) to direct traffic to a specific routing instance, the target routing instance must have a route back to the source to handle return traffic. Typically, a default route pointing back to the core gateway within that routing instance's routing table ensures that return traffic is sent back correctly. Without such a route, return traffic may be dropped or misrouted.

Exam trap

JNCIS-ENT often tests FBF and routing instances, and candidates may overlook the need for a return path in the target routing instance, assuming that the default instance handles it automatically.

How to eliminate wrong answers

Option B is wrong because static ARP entries are not necessary for return traffic handling; ARP resolves IP to MAC, but routing is needed to direct traffic. Option C is wrong because RSVP LSPs are for MPLS traffic engineering, not for basic return traffic in a routing instance. Option D is wrong because a BGP peering session is not required unless dynamic routing is used; a static default route is sufficient and simpler.

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9
MCQhard

An administrator configures filter-based forwarding. The firewall filter uses the action 'then routing-instance custom-vr'. Where must the custom-vr routing instance be defined for the filter to accept this configuration without committing errors?

A.Under the [edit system FBF] hierarchy.
B.Under the [edit interfaces interface-name unit 0 family inet] hierarchy.
C.Under the [edit routing-instances] hierarchy.
D.Under the [edit firewall family inet filter] hierarchy.
AnswerC

Filter-based forwarding requires the target routing instance to exist within the routing-instances hierarchy, so the filter action resolves against a valid instance at commit. Defining custom-vr under [edit routing-instances] satisfies this constraint, allowing the filter term to direct matching traffic into that virtual router without commit errors.

Why this answer

Filter-based forwarding (FBF) requires the target routing instance to exist under the [edit routing-instances] hierarchy before a firewall filter can reference it with the 'then routing-instance' action. Junos validates this reference at commit time, so if custom-vr is not defined as a routing instance, the commit fails with an error. The routing instance is typically of type 'forwarding' or 'virtual-router', and the filter action simply directs matching packets into that instance's forwarding table.

Exam trap

The trap is assuming the routing instance can be defined inline within the filter or interface hierarchy; Junos requires it under [edit routing-instances] and validates the reference at commit, causing a hard failure if missing.

How to eliminate wrong answers

Option A is wrong because [edit system FBF] is not a valid Junos hierarchy — there is no system-level FBF configuration stanza. Option B is wrong because the interface unit family inet hierarchy configures addressing and filters applied to the interface, not the definition of a routing instance; the routing instance must exist separately. Option D is wrong because [edit firewall family inet filter] is where the filter itself (terms and actions) is defined, not where the routing instance is declared — the filter only references the instance by name.

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10
MCQeasy

Which routing-instance type is specifically designed to support Layer 3 VPNs (L3VPNs) utilizing BGP as the-peering protocol and MP-BGP for VPN route distribution?

A.virtual-router
B.forwarding
C.VPLS
D.vrf
AnswerD

The vrf routing-instance type is purpose-built for L3VPNs, holding a separate routing table populated by MP-BGP VPN routes and supporting BGP peering between provider edge devices. Other instance types serve different services, so vrf satisfies the L3VPN requirement.

Why this answer

The vrf routing-instance type is specifically designed for Layer 3 VPNs (L3VPNs) that use BGP for peering and MP-BGP for VPN route distribution. It maintains a separate routing table (RIB) and forwarding table (FIB) per instance, enabling overlapping IP addresses across customers. VRF instances support BGP, OSPF, and other routing protocols, and they are the Junos equivalent of a VRF-lite or MPLS L3VPN VRF.

The other types serve different purposes: virtual-router is for logical routers with separate routing tables but no VPN route-target support, forwarding is for filter-based forwarding, and VPLS is for Layer 2 VPNs.

Exam trap

JNCIS-ENT often tests the distinction between routing-instance types, and candidates frequently confuse virtual-router with vrf because both create separate routing tables; however, only vrf supports the route distinguisher and route target attributes required for BGP/MP-BGP L3VPNs.

How to eliminate wrong answers

Option A is wrong because a virtual-router routing-instance creates a separate routing table but does not support VPN route targets or MP-BGP-based L3VPN signaling; it is used for logical router separation, not L3VPNs. Option B is wrong because a forwarding routing-instance is used for filter-based forwarding (FBF) to direct traffic based on firewall filters, not for BGP/MP-BGP L3VPNs. Option C is wrong because VPLS is a Layer 2 VPN technology that emulates a LAN segment, not a Layer 3 VPN; it uses BGP for auto-discovery but does not provide IP routing separation with VRFs.

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11
MCQhard

An administrator has configured a forwarding-type routing instance to perform filter-based forwarding. Which configuration statement is mandatory under the routing-instances hierarchy to properly define this instance type?

A.set routing-instances dept-fwd routing-options interface ge-0/0/0.0
B.set routing-instances dept-fwd instance-type virtual-router
C.set routing-instances dept-fwd instance-type l3vpn
D.set routing-instances dept-fwd instance-type forwarding
AnswerD

Filter-based forwarding requires the routing instance to be declared with instance-type forwarding, which activates the forwarding table used by firewall filter actions to steer traffic into that instance. Without this statement, the instance cannot perform filter-based forwarding.

Why this answer

Filter-based forwarding (FBF) on Junos requires a routing instance of type 'forwarding'. This instance type creates a Virtual Routing and Forwarding (VRF) table that is populated only by firewall filter 'then routing-instance' actions, not by a routing protocol. The mandatory statement is therefore 'set routing-instances <name> instance-type forwarding'.

Exam trap

JNCIS-ENT often tests the confusion between 'virtual-router' (full VRF with protocols) and 'forwarding' (FBF-only, no protocols); candidates pick virtual-router thinking it is the generic VRF type, but FBF specifically requires 'forwarding'.

How to eliminate wrong answers

Option A is wrong because 'routing-options interface' is not a valid statement under routing-instances for defining the instance type; interfaces are assigned via 'interface' under the routing-instance itself, and this does not set the instance type. Option B is wrong because 'instance-type virtual-router' creates a full VRF with its own routing protocol processes and RIB, which is used for VRF-lite, not for filter-based forwarding. Option C is wrong because 'instance-type l3vpn' is used for Layer 3 VPN (BGP/MPLS VPN) configurations with route distinguishers and route targets, not for FBF.

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12
MCQeasy

What is the primary function of a Junos routing instance of type 'forwarding'?

A.To terminate BGP sessions from multiple external peers
B.To run multiple independent OSPF instances
C.To provide transparent bridging across WAN circuits
D.To support filter-based forwarding without running routing protocols
AnswerD

A forwarding routing instance holds only forwarding tables, with no routing protocol process, and is used with firewall filters to direct traffic into specific next-hop or VRF paths. This satisfies filter-based forwarding without protocol adjacencies.

Why this answer

A Junos routing instance of type 'forwarding' is used to support filter-based forwarding (FBF) without running routing protocols. It allows traffic to be directed to specific next-hops based on firewall filter match conditions, using a separate routing table (the forwarding instance's table) that contains only static routes or interface routes. This is ideal for policy-based routing scenarios where you don't need a full routing protocol.

Exam trap

JNCIS-ENT often tests the distinction between forwarding, virtual-router, and VRF instances — candidates may pick virtual-router for FBF, but forwarding is the correct type when no routing protocols are needed.

How to eliminate wrong answers

Option A is wrong because terminating BGP sessions from multiple external peers is done with a VRF or a virtual-router routing instance, not a forwarding instance — forwarding instances don't run BGP. Option B is wrong because running multiple independent OSPF instances requires a virtual-router routing instance, which has its own protocol processes; forwarding instances do not support routing protocols. Option C is wrong because transparent bridging across WAN circuits is a Layer 2 function, typically handled by a bridge domain or VPLS, not a forwarding routing instance.

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13
Multi-Selectmedium

Which TWO attributes distinguish direct routes from static routes in Junos OS? (Choose two)

Select 2 answers
A.Static routes are created automatically when an interface comes up.
B.Direct routes represent subnets attached to active local interfaces.
C.Direct routes require manual IP address configuration under routing-options.
D.Static routes cannot be used with recursive next-hops.
E.Direct routes have a default preference of 0, whereas static routes have a default preference of 5.
AnswersB, E

Direct routes are derived from the subnets configured on active local interfaces, so they appear only while the interface is up. Static routes are manually configured and remain regardless of interface state, which is the distinguishing axis.

Why this answer

Option B is correct because direct routes in Junos OS are automatically installed in the routing table for the subnets configured on active local interfaces, representing directly connected networks. Option E is correct because Junos assigns direct routes a default preference of 0, while static routes carry a default preference of 5, making direct routes more preferred when both exist for the same prefix. Option A is wrong because static routes are manually configured, not automatically created when an interface comes up; that behavior describes direct/interface routes.

Option C is wrong because direct routes do not require manual configuration under routing-options; they are derived from interface addresses, whereas static routes are configured under routing-options. Option D is wrong because static routes can use recursive next-hops, resolving the next-hop through another route in the routing table.

Exam trap

JNCIS-ENT often tests the default preferences of route types; candidates may confuse direct routes (preference 0) with static routes (preference 5) or assume static routes are automatically created.

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14
MCQmedium

You are troubleshooting an aggregate route that is not being advertised to BGP peers. You verify that contributing routes are active in the routing table. What command should you use to check if the aggregate route itself is successfully generated and active in the local routing table?

A.show route summary aggregate
B.show bgp aggregate-routes
C.show route protocol aggregate
D.show routing-options aggregate detail
AnswerC

Aggregate routes appear in the routing table under the aggregate protocol. 'show route protocol aggregate' filters the table to those entries, confirming whether the aggregate was generated and is active before investigating why BGP is not advertising it.

Why this answer

The command 'show route protocol aggregate' displays all routes in the routing table that were learned via the aggregate protocol. This allows you to verify if the aggregate route is active and installed. If the aggregate is not shown, it means it is not active, likely due to no contributing routes.

The other commands are either invalid or do not show the aggregate route in the local routing table.

Exam trap

The trap is using a configuration show command instead of a routing table show command; candidates might pick 'show routing-options aggregate' which shows config, not active routes.

How to eliminate wrong answers

Option A is wrong because 'show route summary aggregate' is not a valid command; 'show route summary' gives a summary but does not filter by protocol. Option B is wrong because 'show bgp aggregate-routes' is not a valid command; BGP does not have a specific aggregate-routes show command. Option D is wrong because 'show routing-options aggregate detail' displays the configuration, not the active routing table entries.

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15
MCQeasy

Which statement best describes the behavior of a local route in Junos OS?

A.They represent IP addresses assigned directly to the router's local interfaces.
B.They are static routes learned from neighbor routers via CDP.
C.They are manual loopback routes configured by network administrators.
D.They are generated automatically whenever a BGP session drops.
AnswerA

Local routes in Junos OS are host routes (/32 for IPv4, /128 for IPv6) installed for each address configured on the router's own interfaces, pointing to the loopback or discard next-hop. They satisfy the stem's requirement by describing addresses assigned directly to local interfaces, distinguishing them from routes learned via routing protocols.

Why this answer

A local route in Junos OS represents the IP addresses assigned directly to the router's local interfaces. These routes are automatically installed in the routing table with a next-hop of the local interface and are used for traffic destined to the router itself. They are not learned from neighbors or manually configured as static routes.

Exam trap

JNCIS-ENT often tests the distinction between direct and local routes, and candidates may confuse local routes with static or loopback routes, or think they are learned dynamically.

How to eliminate wrong answers

Option B is wrong because local routes are not learned from neighbor routers via CDP; CDP is a Cisco protocol and not used for routing. Option C is wrong because local routes are not manual loopback routes; loopback routes are typically static or interface routes, but local routes specifically refer to directly connected interface addresses. Option D is wrong because local routes are not generated when BGP sessions drop; they are always present for configured interface addresses.

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16
MCQmedium

You have configured a static route with a next-hop of 10.0.0.1 and a preference of 10. Another static route to the same destination has a next-hop of 10.0.0.2 and a preference of 5. Both next-hops are reachable. Which route will be active in the routing table?

A.The route with next-hop 10.0.0.2 because it has a lower preference.
B.Both routes will be active and load balancing will occur.
C.Neither route will be active because of conflicting preferences.
D.The route with next-hop 10.0.0.1 because it has a higher preference.
AnswerA

Junos uses lower preference values to indicate more preferred routes. The route with preference 5 is preferred over the one with preference 10. Therefore, the route with next-hop 10.0.0.2 will be installed in the routing table and used for forwarding, assuming both next-hops are reachable.

Why this answer

Junos selects the static route with the lowest preference value. Since the route with next-hop 10.0.0.2 has a preference of 5, which is lower than 10, it becomes the active route. The other route remains in the routing table but is not used for forwarding.

Exam trap

The trap here is assuming that a higher preference value is better, when in Junos, lower preference values are preferred.

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17
MCQmedium

You want to ensure that a static route is only installed in the routing table when a specific tracked object or ping test succeeds. Which Junos feature should you pair with the static route?

A.OSPF sham-links
B.Keepalive timers on static routes
C.RPM (Real-time Performance Monitoring) with static route tracking
D.BFD synchronized static routes
AnswerC

RPM probes send periodic ICMP or TCP checks to a target; pairing the static route with the RPM test means the route is installed only while the probe succeeds. This conditional installation is the tracked-object behaviour the scenario demands.

Why this answer

RPM (Real-time Performance Monitoring) in Junos allows you to configure probes that periodically test reachability of a target (e.g., via ICMP ping) and track the results. When you associate a static route with an RPM probe using the `track` option, the route is only installed in the routing table if the probe succeeds. This provides conditional route installation based on real-time performance monitoring, ensuring the static route is active only when the tracked object is reachable.

Exam trap

JNCIS-ENT often tests the confusion between RPM tracking and BFD for static route failover; candidates may think BFD can track arbitrary objects, but BFD only monitors the next-hop liveness of the route itself, not a separate ping target.

How to eliminate wrong answers

Option A is wrong because OSPF sham-links are used in MPLS VPN environments to make a route appear as an inter-area route for OSPF, not for conditional static route installation. Option B is wrong because keepalive timers on static routes are used for failover between primary and secondary static routes based on next-hop reachability, but they do not tie route installation to a specific tracked object or ping test. Option D is wrong because BFD (Bidirectional Forwarding Detection) synchronized static routes are used to quickly detect failures on a static route's next-hop and remove the route, but they do not conditionally install a route based on a separate tracked object or ping test; BFD only monitors the next-hop of the static route itself.

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18
MCQhard

An engineer configures multiple static routes to the same destination with different preference values. When all paths are up, how does Junos select which route is active in the routing table?

A.The route configured last in the candidate configuration file becomes active.
B.The route with the lowest preference value is installed as active.
C.The route with the highest metric value is preferred.
D.All routes are installed into the forwarding table for equal-cost multi-path load balancing.
AnswerB

Junos assigns each static route a preference value, and the route with the lowest preference wins the active-route election, provided its next hop is reachable. Since the stem specifies multiple static routes to one destination with differing preferences, the numerically lowest preference is installed as active in the routing table.

Why this answer

Junos uses route preference (also called administrative distance) to select the active route when multiple routes to the same destination exist. Lower preference values are preferred, so a static route with preference 5 beats one with preference 10. Only the route with the lowest preference is installed as active in the routing table and subsequently into the forwarding table (unless ECMP conditions apply).

Exam trap

JNCIS-ENT often tests the preference-vs-metric distinction — candidates confuse 'lower is better' for preference with metric comparisons, or assume configuration order matters as it might in some other vendor platforms.

How to eliminate wrong answers

Option A is wrong because Junos does not use configuration order to break ties — the candidate configuration is a set-based hierarchy, not a sequential script, so 'last configured' has no meaning for route selection. Option C is wrong because metric is used for tie-breaking within the same protocol after preference, and higher metric is generally less preferred, not more — the statement inverts the logic. Option D is wrong because ECMP only occurs when routes have equal preference AND equal metric AND the protocol supports multipath; different preference values explicitly prevent ECMP from installing multiple paths.

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19
Multi-Selectmedium

Which TWO parameters can be modified within a static route configuration to control path selection and backup behavior? (Choose two)

Select 2 answers
A.MED (Multi-Exit Discriminator)
B.Qualified next-hop with custom preference
C.AS-path length
D.Local preference attribute
E.Preference (administrative distance)
AnswersB, E

Qualified next-hop with custom preference lets a static route track a specific next hop and carry a non-default preference value. Lower preference wins in Junos, so this satisfies the stem's path-selection and backup requirements: the route stays installed only while its qualified next hop resolves, and preference orders it against alternates.

Why this answer

Option B is correct because in a static route you can specify a qualified next-hop and assign it a custom preference, allowing the router to prefer one next-hop over another for the same destination and thereby influence path selection and provide backup behavior. Option E is correct because the preference (administrative distance) value on a static route determines how it competes with routes from other protocols and with other static routes, so modifying it directly controls which route is installed and which serves as backup. Options A, C, and D are incorrect because MED, AS-path length, and local preference are BGP path attributes used in BGP route selection, not parameters that can be configured within a static route.

Exam trap

The trap is confusing BGP attributes (MED, local preference, AS-path) with static route parameters; candidates must remember that static routes only support preference and qualified next-hop for path control.

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20
MCQhard

An engineer configures an aggregate route for 172.16.0.0/16 on a Junos device. However, the aggregate route is not active in the routing table. What is the primary requirement for an aggregate route to become active?

A.An explicit static route matching the aggregate prefix must be configured.
B.At least one more-specific contributing route must exist in the routing table.
C.A discard policy must be explicitly defined under the aggregate route definition.
D.The aggregate route must be redistributed using BGP or OSPF.
AnswerB

Junos aggregate routes are inactive until a contributing more-specific route is present in the routing table. Without at least one such route, the aggregate is not installed, so the 172.16.0.0/16 entry remains hidden and cannot be advertised or used for forwarding.

Why this answer

A Junos aggregate route becomes active only when at least one more-specific contributing route exists in the routing table. The aggregate is generated as a discard route (or with a configured next-hop) and is installed only if a longer-prefix route covered by the aggregate is present.

Exam trap

The trap is confusing Junos aggregate routes with static summary routes; candidates assume the aggregate is always active once configured, forgetting the more-specific contributor requirement.

How to eliminate wrong answers

Option A is wrong because an explicit static route matching the aggregate prefix would conflict with the aggregate itself and is not required — the aggregate is defined under '[edit routing-options aggregate]', not as a static route. Option C is wrong because a discard policy is not required; by default the aggregate installs as a discard route, and 'discard' or 'reject' is optional configuration. Option D is wrong because redistribution via BGP or OSPF is not a prerequisite for the aggregate to become active in the local routing table — redistribution affects advertisement, not activation.

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21
MCQhard

An administrator configures a static route with a next-hop that points to an indirect (recursive) address. What condition must be met for this static route to become active in the inet.0 routing table?

A.A more direct route to the next-hop IP must already exist and be active in inet.0.
B.The static route preference must be set lower than 1.
C.The next-hop IP must be directly connected to a physical interface on the local router.
D.BGP multipath must be enabled under routing-options.
AnswerA

A recursive static next-hop requires the routing table to already resolve that address. If no active, more direct route to the next-hop exists in inet.0, the static route stays hidden. This satisfies the stem's condition for the route becoming active.

Why this answer

For a static route with an indirect (recursive) next-hop to become active in inet.0, the router must already have an active route to that next-hop IP in inet.0. This is the definition of recursive resolution: the next-hop must be reachable via another route in the same routing table. Without this, the static route remains hidden.

Exam trap

The trap is confusing recursive next-hop resolution with directly connected next-hops — candidates often think the next-hop must be directly connected, but Junos allows recursive resolution as long as a route to the next-hop exists.

How to eliminate wrong answers

Option B is wrong because static route preference must be a value between 0 and 255, and setting it lower than 1 (i.e., 0) is not a valid condition for activation — preference affects route selection, not next-hop resolution. Option C is wrong because the next-hop does not need to be directly connected; that is the whole point of a recursive next-hop — it can be reachable via another route. Option D is wrong because BGP multipath is unrelated to static route activation and is used for load balancing across multiple BGP paths.

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22
Multi-Selecthard

When configuring load balancing in Junos OS, which THREE header fields can be included in the hashing algorithm to compute the ECMP path? (Choose three)

Select 3 answers
A.MAC address destination
B.Layer 4 TCP/UDP port numbers
C.Source IP address
D.VLAN ID tagging bits
E.Destination IP address
AnswersB, C, E

Junos OS ECMP hashing supports Layer 4 fields, so including TCP/UDP port numbers spreads flows across paths even when source and destination IP addresses match. This satisfies the requirement for a transport-layer header field in the hash, complementing the Layer 3 fields already available.

Why this answer

In Junos OS, the ECMP hashing algorithm used for load balancing can incorporate Layer 3 and Layer 4 header fields to distribute traffic across multiple equal-cost next hops. Option B (Layer 4 TCP/UDP port numbers) is correct because including transport-layer port numbers enables per-flow load balancing, so different sessions between the same hosts can take different paths. Option C (Source IP address) is correct because the source IP is a standard Layer 3 field used in the hash, allowing traffic from different sources to be spread across ECMP paths.

Option E (Destination IP address) is correct because the destination IP is also a standard Layer 3 field in the hash, ensuring flows to different destinations are distributed. Option A (MAC address destination) is not included because ECMP hashing in Junos operates on Layer 3/Layer 4 fields, not on the destination MAC address. Option D (VLAN ID tagging bits) is not included because VLAN ID is a Layer 2 field and is not part of the ECMP hash computation in Junos OS.

Exam trap

JNCIS-ENT often tests which OSI layers contribute to ECMP hashing — candidates incorrectly include Layer 2 fields like MAC or VLAN, not realizing Junos ECMP is an IP-layer function.

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23
MCQeasy

Which command is used to display all configured static routes along with their active/inactive status in Junos?

A.show static routes summary
B.show route protocol static
C.show configuration routing-options static
D.show route table inet.0 static
AnswerB

The show route protocol static command filters the routing table to display only static routes, listing each with its active or inactive status. Other show route variants display all protocols or lack the protocol filter needed here.

Why this answer

The command `show route protocol static` queries the routing table (by default inet.0) and filters for routes whose protocol is static. This output includes both active routes (marked with `*`) and inactive routes (marked with `-`), along with next-hop, preference, and metric information. It directly answers the question by showing all configured static routes and their active/inactive status.

Exam trap

JNCIS-ENT often tests the distinction between configuration commands (which show intended configuration) and operational commands (which show actual routing table state), so candidates must remember that `show configuration` does not display active/inactive status.

How to eliminate wrong answers

Option A is wrong because `show static routes summary` is not a valid Junos command; Junos does not have a `show static` hierarchy. Option C is wrong because `show configuration routing-options static` displays the static route configuration from the candidate or active configuration, but it does not show active/inactive status or any runtime routing table information. Option D is wrong because `show route table inet.0 static` is syntactically incorrect; the correct syntax is `show route table inet.0 protocol static` or simply `show route protocol static` (which defaults to inet.0).

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24
Multi-Selecthard

An administrator wants to configure load balancing across multiple static routes. Which THREE configuration elements are required to successfully implement ECMP load balancing for static routes in Junos? (Choose three)

Select 3 answers
A.BFD enabled on all static route next-hops.
B.Export of the load-balancing policy under 'routing-options forwarding-table export'.
C.A routing policy containing the 'then load-balance' action.
D.A virtual-router routing instance wrapper.
E.Multiple static routes to the same destination with equal preference and metric.
AnswersB, C, E

Defining the policy alone does nothing; it must be attached via 'routing-options forwarding-table export'. This binding applies the load-balancing policy to the forwarding table, enabling multiple equal-cost next hops to be installed and used, which the ECMP scenario requires.

Why this answer

To implement ECMP for static routes in Junos, you must first have multiple static routes to the same destination with equal preference and metric, because ECMP only installs paths of identical preference/metric into the forwarding table (option E). You then need a routing policy that contains the 'then load-balance' action, which tells Junos to install multiple next-hops for that destination rather than selecting a single best path (option C). Finally, that policy must be applied to the forwarding table via 'routing-options forwarding-table export', which is the mechanism that activates per-prefix load balancing for the routes (option B).

BFD is not required for ECMP; it is an optional failure-detection mechanism (option A). A virtual-router routing instance is unrelated to ECMP and is used for routing-instance separation, not load balancing (option D).

Exam trap

JNCIS-ENT often tests the misconception that simply configuring multiple equal-cost static routes is enough for ECMP — candidates forget the mandatory forwarding-table export policy that actually installs multiple next-hops into the FIB.

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25
Multi-Selectmedium

Which TWO statements accurately describe the behavior and characteristics of a routing instance of type 'forwarding'? (Choose two)

Select 2 answers
A.It automatically generates a default route pointing to the loopback interface.
B.It runs independent OSPF and BGP instances.
C.It requires MP-BGP for VPN label signaling.
D.It is primarily used for filter-based forwarding applications.
E.It maintains a separate forwarding table without running dynamic routing protocols.
AnswersD, E

Forwarding-type routing instances are designed for filter-based forwarding, where firewall filters direct matching traffic into a separate routing table for alternate next-hop treatment. This is their primary deployment scenario, distinguishing them from virtual-router or VRF instances.

Why this answer

Option D is correct because a 'forwarding' routing instance (also called a VRF-lite style instance) is designed for filter-based forwarding (FBF), where firewall filters on the ingress interface classify traffic and direct it into the instance's own routing table to control next-hop selection. Option E is correct because a forwarding-type instance maintains its own separate forwarding/routing table (RIB/FIB) but does not run any dynamic routing protocols such as OSPF, IS-IS, or BGP within it; routes are populated statically or via policy/filter actions. Option A is wrong because a forwarding instance does not automatically create a default route to the loopback interface; any default route must be configured manually or injected by policy.

Option B is wrong because running independent OSPF and BGP instances is characteristic of a VRF-type routing instance, not a forwarding instance. Option C is wrong because MP-BGP for VPN label signaling is associated with VRF instances in MPLS L3VPN deployments, not with forwarding instances, which are local to the device and do not use VPN labels.

Exam trap

JNCIS-ENT often tests the confusion between 'forwarding' and 'virtual-router' routing instances — candidates incorrectly assume forwarding instances run routing protocols or auto-generate routes, when in fact they are protocol-less and require static configuration.

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26
MCQeasy

What is the default preference value for a direct route in Junos OS?

A.5
B.20
C.0
D.10
AnswerC

A direct route in Junos OS carries a default preference of 0, the lowest value available, which makes it the most preferred route in the routing table. This satisfies the stem's requirement precisely: directly connected interfaces always win over static, OSPF, or BGP routes when identical prefixes compete.

Why this answer

In Junos OS, the default preference (administrative distance) for a direct route is 0. This is the highest priority among all route types, ensuring that directly connected networks are always preferred over routes learned via dynamic protocols or static configuration. The value 0 reflects that a directly connected interface is the most trusted source of routing information.

Exam trap

JNCIS-ENT often tests the memorization of default preference values, and candidates frequently confuse the preference for direct routes (0) with that of static routes (5) or OSPF (10).

How to eliminate wrong answers

Option A is wrong because 5 is the default preference for static routes in Junos OS, not direct routes. Option B is wrong because 20 is not a standard default preference for any common route type in Junos; it might be confused with OSPF internal preference (10) or something else. Option D is wrong because 10 is the default preference for OSPF internal routes, not direct routes.

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27
MCQhard

An administrator implements filter-based forwarding and applies a firewall filter on the ingress interface. However, traffic matching the filter is dropped rather than routed to the alternate routing instance. Upon investigation, what is the most likely cause of this issue?

A.The ingress interface is configured as a trunk port.
B.The destination IP address does not have a matching route in the alternate routing instance's table.
C.The firewall filter term lacks a 'count' action statement.
D.The routing instance type is set to virtual-router instead of forwarding.
AnswerB

Filter-based forwarding relies on the alternate routing instance having a matching route for the destination. If none exists, the packet cannot be forwarded and is dropped, which is the most likely cause of the described behaviour.

Why this answer

Filter-based forwarding (FBF) works by matching traffic with a firewall filter and then using a 'routing-instance' action to steer it into an alternate routing table. If the alternate routing instance has no route for the destination IP, the packet cannot be forwarded and is dropped, which matches the symptom described.

Exam trap

JNCIS-ENT often tests the assumption that FBF 'just works' once the filter is applied — the trap is forgetting that the alternate routing instance needs its own populated routing table for the destination.

How to eliminate wrong answers

Option A is wrong because whether the ingress interface is a trunk or access port does not affect FBF functionality — FBF operates on routed traffic regardless of port mode. Option C is wrong because a 'count' action is optional for diagnostics; its absence does not cause traffic to be dropped. Option D is wrong because 'virtual-router' is a valid routing instance type for FBF (it provides a separate routing table), so this is not the cause of the drop.

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28
MCQmedium

You are configuring a static route to a destination and want to ensure that the route is not redistributed into OSPF. Which configuration statement should you use?

A.reject
B.passive
C.no-readvertise
D.no-install
AnswerC

The 'no-readvertise' statement prevents the static route from being redistributed into dynamic routing protocols, including OSPF. It is configured under the static route. This is useful when you want the route to be used locally but not advertised to other routers, maintaining control over routing information propagation.

Why this answer

The 'no-readvertise' statement is specifically designed to prevent a static route from being redistributed into dynamic routing protocols. It ensures the route is used locally but not advertised, which is exactly what is needed to keep the route out of OSPF.

Exam trap

The trap here is confusing 'no-readvertise' with other static route options like 'reject' or 'no-install', which serve different purposes.

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29
Multi-Selectmedium

An engineer is configuring static routes in Junos OS and wants to ensure high availability. Which TWO features can be implemented with static routes to achieve path redundancy? (Choose two)

Select 2 answers
A.Qualified next-hop with varying preference values
B.IGMP snooping on static interfaces
C.OSPF area stubbing
D.Recursive next-hop tracking via RPM or routing table lookups
E.BGP AS-path prepending on static routes
AnswersA, D

A qualified next-hop lists multiple next-hop addresses with different preference values, so Junos installs the preferred path and switches to the alternate when it fails. This provides static route redundancy without dynamic protocols, satisfying the high-availability requirement for path redundancy.

Why this answer

Option A (Qualified next-hop with varying preference values) is correct because Junos static routes support multiple qualified next-hops, each with its own preference; if the primary next-hop fails, the route with the next-lower preference becomes active, providing path redundancy. Option D (Recursive next-hop tracking via RPM or routing table lookups) is correct because a static route can resolve its next-hop recursively, and RPM (Real-time Performance Monitoring) probes or routing-table lookups can detect when the resolved next-hop becomes unreachable, allowing the route to be withdrawn or replaced. Option B (IGMP snooping) is a Layer 2 multicast optimization and does not provide static-route path redundancy.

Option C (OSPF area stubbing) is a dynamic routing design technique for reducing LSAs, not a static-route feature. Option E (BGP AS-path prepending) is a BGP path-manipulation tool and cannot be applied to plain static routes.

Exam trap

The trap is that candidates reach for dynamic-protocol features (OSPF stubbing, BGP prepending) when the question explicitly asks about static route redundancy — the answer must be a static-route-native mechanism.

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30
MCQeasy

Which command allows you to inspect the active forwarding table entries and verify next-hops on a Junos router?

A.show route forwarding-table
B.show interfaces extensive
C.show pfe traffic
D.show routing-engine status
AnswerA

The forwarding table holds the router's active next-hop and egress interface entries, distinct from the routing table's protocol paths. Running this command displays those installed forwarding entries, letting you confirm which next-hop each destination actually resolves to on the Junos device.

Why this answer

'show route forwarding-table' displays the active forwarding table entries that the Packet Forwarding Engine (PFE) actually uses to forward packets, including next-hop information. This is the command that verifies what the router is really doing at the forwarding plane, not just what the routing protocol advertised.

Exam trap

JNCIS-ENT often tests the distinction between the control-plane routing table ('show route') and the data-plane forwarding table ('show route forwarding-table') — candidates pick the wrong command when asked about active forwarding entries.

How to eliminate wrong answers

Option B is wrong because 'show interfaces extensive' displays detailed interface statistics and errors, not forwarding table entries or next-hops. Option C is wrong because 'show pfe traffic' shows PFE traffic statistics, not the forwarding table contents. Option D is wrong because 'show routing-engine status' shows the state of the Routing Engine (CPU, memory, mastership), which is unrelated to forwarding table inspection.

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31
MCQeasy

When configuring a routing instance of type 'virtual-router', what is required to allow communication between the virtual router instance and the default routing instance?

A.Connect a physical cable between two ports on the router (cable-patch).
B.Configure static routes with identical preferences in both instances.
C.Disable firewall filters on all loopback interfaces.
D.Configure leaking routes between instances using rib-groups or routing policies.
AnswerD

Virtual routers maintain separate routing tables, so no route sharing occurs by default. Leaking routes via rib-groups or routing policies imports prefixes between the virtual router and the default instance, which is what enables communication between them.

Why this answer

To allow communication between a virtual-router routing instance and the default routing instance, you must configure route leaking using rib-groups or routing policies. Virtual routers have separate routing tables, so routes are not shared by default. Rib-groups can copy routes from one table to another, or routing policies can export/import routes between instances.

Exam trap

JNCIS-ENT often tests the isolation of routing instances, and candidates may assume that virtual routers can communicate by default or that static routes are sufficient, overlooking the need for explicit route leaking.

How to eliminate wrong answers

Option A is wrong because connecting a physical cable is not required; virtual routers can communicate logically via route leaking. Option B is wrong because static routes with identical preferences do not automatically share routes between instances; they must be explicitly configured in each instance, and without leaking, they won't be known. Option C is wrong because disabling firewall filters on loopback interfaces is irrelevant to inter-instance communication.

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32
MCQeasy

By default, what is the Junos routing protocol preference value assigned to static routes?

A.170
B.10
C.150
D.5
AnswerD

Static routes carry the default Junos preference of 5, making them more trusted than OSPF internal (10), IS-IS (18) and RIP (100), but less than direct and local routes. This default value applies unless explicitly overridden with the preference statement.

Why this answer

In Junos OS, the default routing protocol preference (also called administrative distance) for static routes is 5. This low value makes static routes highly preferred over routes learned from dynamic protocols like OSPF (preference 10) or BGP (preference 170). The preference value is used to select the active route when multiple routes to the same destination exist from different sources.

Exam trap

JNCIS-ENT often tests the default preference values of various routing protocols, and candidates frequently confuse static routes (5) with OSPF internal (10) or BGP (170), leading to incorrect answers.

How to eliminate wrong answers

Option A is wrong because 170 is the default preference for BGP routes, not static routes. Option B is wrong because 10 is the default preference for OSPF internal routes, not static routes. Option C is wrong because 150 is the default preference for OSPF external routes (or sometimes used for other protocols like RIP, but not static).

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33
Multi-Selecthard

When configuring Filter-Based Forwarding (FBF), which THREE components are absolutely mandatory for successful operation? (Choose three)

Select 3 answers
A.A firewall filter with 'then routing-instance <name>' action.
B.A routing instance of type 'forwarding' or 'virtual-router'.
C.Application of the firewall filter as input on the ingress interface.
D.BGP multipath enabled across all core interfaces.
E.An RSVP-TE LSP tunnel configured between the routers.
AnswersA, B, C

FBF requires a firewall filter whose matching term carries the 'then routing-instance <name>' action, redirecting matched traffic into the target instance. Without this action, packets follow the normal forwarding path and the filter performs no redirection.

Why this answer

Option A is correct because FBF requires a firewall filter that matches traffic and uses the 'then routing-instance <name>' action to redirect matching packets into the alternate routing table. Option B is correct because that action must reference a routing instance of type 'forwarding' (or 'virtual-router'), which provides the separate routing table where the redirected traffic is resolved. Option C is correct because the filter must be applied as an input filter on the ingress interface so that packets are classified and redirected before the normal destination lookup occurs.

Option D is incorrect because BGP multipath is a load-balancing feature and is not required for FBF to function. Option E is incorrect because RSVP-TE LSPs are an MPLS traffic-engineering mechanism and are unrelated to the mandatory FBF configuration components.

Exam trap

The trap is overthinking FBF as requiring advanced routing features (BGP multipath, MPLS LSPs) when it is actually a simple three-part construct: filter action, routing instance, and ingress application.

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34
MCQeasy

Which Junos routing instance type is best suited when you want to run MPLS L3VPNs on a Provider Edge (PE) router?

A.forwarding
B.virtual-router
C.vrf
D.no-structural-instance
AnswerC

The vrf instance type maintains a separate routing table with MPLS label signalling, which is what PE routers require to hold customer L3VPN routes. Other instance types, such as virtual-router, lack the VRF-specific import/export target handling for L3VPN.

Why this answer

L3VPN routing instances are used on PE routers to maintain customer-specific VRF routing tables and exchange VPN-IPv4 routes via MP-BGP.

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35
MCQmedium

You have configured multiple static routes to the same destination with different preference values. When does Junos install a static route into the forwarding table (FIB)?

A.Only the static route with the highest preference value is installed into the FIB.
B.Only the static route with the lowest preference value is installed into the FIB.
C.All static routes are installed into the FIB, and traffic is automatically load-balanced across them.
D.All valid static routes are installed into the FIB regardless of preference values.
AnswerB

Junos selects the active route by comparing preference values, and only the route with the lowest preference is installed into the forwarding table. Higher-preference static routes to the same destination remain in the routing table as backups, becoming active only if the preferred route is withdrawn.

Why this answer

Junos uses preference (administrative distance) to rank routes from the same or different protocols; the route with the lowest preference value is preferred and installed into the forwarding table (FIB). If multiple static routes to the same destination have equal preference, all can be installed for ECMP, but when preferences differ, only the lowest-preference route wins. This mirrors the standard 'lower is better' convention used by Junos for route preference.

Exam trap

The trap here is the direction of preference — many candidates confuse Junos 'preference' (lower is better) with Cisco 'administrative distance' (also lower is better) but then second-guess themselves, or they confuse preference with 'metric' where higher can sometimes be preferred depending on protocol.

How to eliminate wrong answers

Option A is wrong because it inverts the rule — Junos prefers the lowest preference value, not the highest. Option C is wrong because load balancing only occurs when routes have equal preference (and equal metric); differing preferences cause only one route to be selected. Option D is wrong because Junos does not install all valid routes regardless of preference — preference is specifically used to break ties and select the best path.

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36
MCQmedium

You are configuring a static route on a Junos device to a remote network reachable via a point-to-point interface. After committing, you notice the route appears in the routing table but is marked as hidden. Which of the following is the most likely cause?

A.The static route lacks a valid preference value.
B.The next-hop address is not reachable through a direct interface.
C.The static route is configured with the 'no-readvertise' option.
D.The route is being rejected by an import policy.
AnswerB

When a static route's next-hop is not directly reachable via a connected interface, Junos marks the route as hidden. This often occurs when the next-hop is not resolved by a direct route, such as when the interface is down or the next-hop is on a non-connected subnet. The route remains hidden until the next-hop becomes reachable.

Why this answer

A static route is hidden when its next-hop cannot be resolved to a direct interface. Junos requires that the next-hop be reachable via a connected route for the static route to be active. If the interface is down or the next-hop is not on a directly connected subnet, the route remains hidden until reachability is restored.

Exam trap

The trap here is assuming that a missing preference or a policy causes a static route to be hidden, when the actual requirement is next-hop reachability.

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37
MCQmedium

You need to configure a static floating route that will only become active if the primary dynamic route learned via OSPF fails. Which configuration parameter must be adjusted to achieve this behavior?

A.as-path prepend
B.local-preference
C.preference
D.metric
AnswerC

Setting a higher preference value than OSPF's default (10) keeps the static route inactive in the routing table while the OSPF route exists. Junos installs only the route with the lowest preference, so the floating static activates solely when OSPF withdraws, satisfying the failover constraint.

Why this answer

In Junos, route preference (also called administrative distance) determines which route wins when multiple protocols offer a path to the same destination. OSPF's default preference is 10, while a static route's default preference is 5 — meaning the static route would normally win. To make the static route a floating (backup) route, you must raise its preference above OSPF's (e.g., 'set routing-options static route 10.0.0.0/24 next-hop x.x.x.x preference 200') so it is only installed when the OSPF route disappears.

Exam trap

The trap is confusing preference (inter-protocol selection, administrative distance) with metric (intra-protocol cost) — candidates pick metric because it sounds like the value that controls route selection, but only preference governs static-vs-OSPF.

How to eliminate wrong answers

Option A is wrong because as-path prepend is a BGP attribute that lengthens the AS_PATH to influence inbound BGP path selection — it has no effect on OSPF or static route preference. Option B is wrong because local-preference is a BGP attribute used for outbound path selection within an AS; it does not apply to OSPF or static routes. Option D is wrong because metric (or cost) is used within a protocol to compare paths of the same protocol — it does not determine preference between different protocols like static vs.

OSPF.

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