JN0-351 Certification Overview - [Sep 14, 2026] Latest JN0-351 PDF Dumps
The Best Juniper JN0-351 Study Guides and Dumps of 2026
Juniper JN0-351 Exam Syllabus Topics:
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NEW QUESTION # 50
You are attempting to configure the initial two aggregated Ethernet interfaces on a router but there are no aggregated Ethernet interfaces available.
In this scenario, which configuration will enable these interfaces on this router?
- A.
- B.
- C.
- D.
Answer: C
Explanation:
Device count should be more than 1.
NEW QUESTION # 51
In addition to the MAC addresses, what information is stored in the bridging table? (Choose two.)
- A. preamble of Ethernet packet
- B. MAC learned time
- C. interface details
- D. ether type details
Answer: B,C
NEW QUESTION # 52
Two routers share the same highest priority and start time.
- A. In this situation, what is evaluated next when determining the designated router? The router with the lowest router ID become the DR.
- B. The routers perform another DR election.
- C. The router with the highest router ID becomes the DR
- D. The router with the highest MAC address become the DR
Answer: C
Explanation:
According to the OSPF protocol, the designated router (DR) is the router that acts as the focal point for exchanging routing information on a multi-access network segment, such as a LAN1. The DR election process is based on the following criteria, in order of precedence1:
The router with the highest OSPF priority becomes the DR. The default priority is 1, and a priority of 0 means the router will not participate in the election.
If there is a tie in priority, the router with the highest router ID becomes the DR. The router ID is a 32-bit number that uniquely identifies a router in an OSPF domain. It can be manually configured or automatically derived from the highest IP address of a loopback interface or a physical interface.
If there is a tie in router ID, the router that was first to become an OSPF neighbor becomes the DR.
In your scenario, two routers share the same highest priority and start time. This means that they have equal chances of becoming the DR based on the first and third criteria. Therefore, the second criterion will be used to break the tie, which is the router ID. The router with the highest router ID will become the DR, and the other router will become the backup designated router (BDR), which is ready to take over the role of DR if it fails1.
NEW QUESTION # 53
Which statement is correct about graceful Routing Engine switchover (GRES)?
- A. With no other high availability features enabled, routing is preserved and the new master RE does not restart rpd.
- B. The PFE restarts and the kernel and interface information is lost.
- C. When combined with NSR, routing is preserved and the new master RE does not restart rpd.
- D. GRES has a helper mode and a restarting mode.
Answer: C
Explanation:
The Graceful Routing Engine Switchover (GRES) feature in Junos OS enables a router with redundant Routing Engines to continue forwarding packets, even if one Routing Engine fails 1 . GRES preserves interface and kernel information, ensuring that traffic is not interrupted 1 . However, GRES does not preserve the control plane 1 .
To preserve routing during a switchover, GRES must be combined with either Graceful Restart protocol extensions or Nonstop Active Routing (NSR) 1 . When GRES is combined with NSR, nearly 75 percent of line rate worth of traffic per Packet Forwarding Engine remains uninterrupted during GRES 1 . Any updates to the primary Routing Engine are replicated to the backup Routing Engine as soon as they occur 1 .
Therefore, when GRES is combined with NSR, routing is preserved and the new master RE does not restart rpd 1 .
NEW QUESTION # 54
Which two statements about redundant trunk groups on EX Series switches are correct? (Choose two.)
- A. Redundant trunk groups must be connected to the same aggregation switch.
- B. Redundant trunk groups load-balance traffic across two designated uplink interfaces.
- C. If the active link fails, then the secondary link automatically takes over.
- D. Layer 2 control traffic is permitted on the secondary link
Answer: A,C
Explanation:
Redundant Trunk Groups (RTGs) on EX Series switches provide a simple solution for network recovery when a trunk port on a switch goes down 1 . They are configured on the access switch and contain two links:
a primary or active link, and a secondary link 1 . Therefore, option B is correct because if the active link fails, the secondary link automatically starts forwarding data traffic without waiting for normal spanning-tree protocol convergence 1 .
Option D is also correct. In a typical enterprise network composed of distribution and access layers, RTGs are used where one Access switch is connected to two different uplink switches 2 . This implies that RTGs must be connected to the same aggregation switch 2 .
NEW QUESTION # 55
How many bytes of overhead does an IP-IP tunnel add to a packet?
- A. 24 bytes
- B. 14 bytes
- C. 28 bytes
- D. 20 bytes
Answer: D
NEW QUESTION # 56
Exhibit
You are a network operator troubleshooting BGP connectivity.
Which two statements are correct about the output shown in the exhibit? (Choose two.)
- A. The BGP session is not established.
- B. The R1 is configured for AS 65400.
- C. The routers are exchanging IPv4 routes.
- D. Peer 10.32.1.2 is configured for AS 63645.
Answer: A,B
Explanation:
Explanation
Option B suggests that the BGP session is not established. This is correct because in the output, the state of the BGP session is shown as "Idle". In BGP, an "Idle" state means that the BGP session is not currently established1.
Option C suggests that R1 is configured for AS 65400. This is also correct because in the output, it's shown that the local AS number is 654001. The local AS number represents the Autonomous System (AS) number of the router on which you're checking the BGP session1.
NEW QUESTION # 57
Exhibit.
You want to verify prefix information being sent from 10.36.1.4.
Which two statements are correct about the output shown in the exhibit? (Choose two.)
- A. The routes displayed are being learned from an I BGP peer.
- B. The output shows routes that were received prior to the application of any BGP import policies.
- C. The output shows routes that are active and rejected by an import policy.
- D. The routes displayed have traversed one or more autonomous systems.
Answer: B,D
Explanation:
Explanation
The output shown in the exhibit is the result of the command "show ip bgp neighbor 10.36.1.4 received-routes", which displays all received routes (both accepted and rejected) from the specified neighbor.
Option A is correct, because the routes displayed have traversed one or more autonomous systems. This can be seen from the AS_PATH attribute, which shows the sequence of AS numbers that the route has passed through. For example, the route 10.0.0.0/8 has an AS_PATH of 65001 65002, which means that it has traversed AS 65001 and AS 65002 before reaching the local router.
Option B is correct, because the output shows routes that were received prior to the application of any BGP import policies. This can be seen from the fact that some routes have a status code of "r", which means that they are rejected by an import policy. The"received-routes" keyword shows the routes coming from a given neighbor before the inbound policy has been applied. To see the routes after the inbound policy has been applied, the "routes" keyword should be used instead.
Option C is incorrect, because the output does not show routes that are active and rejected by an import policy.
The status code of "r" means that the route is rejected by an import policy, but it does not mean that it is active. The status code of ">" means that the route is active and selected as the best path. None of the routes in the output have both ">" and "r" status codes.
Option D is incorrect, because the routes displayed are not being learned from an IBGP peer. An IBGP peer is a BGP neighbor that belongs to the same AS as the local router. The output shows that the neighbor 10.36.1.4 has a remote AS of 65001, which is different from the local AS of 65002. Therefore, the neighbor is an EBGP peer, not an IBGP peer.
NEW QUESTION # 58
Which statement is correct about IP-IP tunnels?
- A. IP-IP tunnels only support encapsulating IP traffic.
- B. The TTL in the inner packet is decremented during transit to the tunnel endpoint.
- C. IP-IP tunnels only support encapsulating non-IP traffic.
- D. There are 24 bytes of overhead with IP-IP encapsulation.
Answer: A
Explanation:
"The ENCAPSULATOR does not change the inner IP header, except to decrement the TTL and it remains unchanged during its deliver to the endpoint" - only router that encapsulates the inner packet decrements its TTL - during transit, the inner packet is unchanged.
NEW QUESTION # 59
What is the management IP address of the device shown in the exhibit?
- A. 128.0.0.1
- B. 172.23.11.10
- C. 10.210.20.233
- D. 172.23.12.100
Answer: C
Explanation:
The management IP address of the device shown in the exhibit is indicated by the interface
"me0." In the provided output, the "me0" interface is listed with the IP address 10.210.20.233.
NEW QUESTION # 60
Click the Exhibit button.
R1 has a BGP session with a router that has a peer autonomous system number of 64501. It is exchanging routes, and is advertising those routes to IBGP peers. The downstream IBGP peers, however, cannot pass traffic to the advertised networks.
Referring to the exhibit, which configuration change must occur to solve this problem?
- A. The BGP group ext-64501 must include the export next-hop-self policy.
- B. The BGP group int-64503 must include the import next-hop-self policy.
- C. The BGP group ext-64501 must include the import next-hop-self policy.
- D. The BGP group int-64503 must include the export next-hop-self policy.
Answer: D
NEW QUESTION # 61
What are three well-known mandatory BGP attributes? (Choose three.)
- A. community
- B. local preference
- C. next hop
- D. origin
- E. AS path
Answer: C,D,E
NEW QUESTION # 62
Which two statements are correct about VRRP? (Choose two.)
- A. The VRRP group number must match on all participating devices
- B. The VRRP group number must be unique on all participating devices
- C. The virtual IP address must match on all participating devices
- D. The virtual IP address must be unique on all participating devices
Answer: A,C
Explanation:
The virtual IP address must match on all participating devices - All routers in the same VRRP group must be configured with the same virtual IP address to provide redundancy.
The VRRP group number must match on all participating devices - All routers in the same VRRP group must have the same group number to identify the VRRP group.
NEW QUESTION # 63
Which two statements are correct about aggregate routes in Junos OS? (Choose two.)
- A. Aggregate routes can be configured with a policy to control which contributing routes are included.
- B. Aggregate routes cannot have their next hop set to "discard."
- C. An aggregate route becomes active only when at least one contributing route is present, similar to a generated route.
- D. An aggregate route is installed in the routing table regardless of whether contributing routes exist.
Answer: A,C
Explanation:
Similar to generated routes, an aggregate route in Junos OS becomes active in the routing table only when at least one contributing (more specific) route matching the aggregate is present.
Administrators can apply a policy to an aggregate route configuration to control which specific contributing routes are eligible to trigger the aggregate, and aggregate routes are commonly configured with a "discard" next hop to prevent routing loops for unused portions of the aggregated address space.
NEW QUESTION # 64
You are configuring a router as a new Level 1 router in an existing Level 1 area. The NET address for an existing Level 1 router is 49.0011.1111.2222.3333.00. The new router must form a Level 1 adjacency with the existing router. What should be the area ID in this scenario?
- A. 00
- B. 0
- C. 0011
- D. 1
Answer: C
NEW QUESTION # 65
You are troubleshooting a BGP routing issue between your network and a customer router and are reviewing the BGP routing policies. Which two statements are correct in this scenario? (Choose two.)
- A. Export policies are applied to routes in the RIB-ln table.
- B. Import policies are applied to routes in the RIB-Local table.
- C. Import policies are applied after the RIB-ln table.
- D. Export policies are applied after the RIB-Local table.
Answer: C,D
Explanation:
In BGP, routing policies are used to control the flow of routing information between BGP peers 1 .
Option C suggests that import policies are applied after the RIB-In table. This is correct because import policies in BGP are applied to routes that are received from a BGP peer, before they are installed in the local BGP Routing Information Base (RIB-In) 1 . The RIB-In is a database that stores all the routes that are received from all peers 1 .
Option D suggests that export policies are applied after the RIB-Local table. This is correct because export policies in BGP are applied to routes that are being advertised to a BGP peer, after they have been selected from the local BGP Routing Information Base (RIB-Local) 1 . The RIB-Local is a database that stores all the routes that the local router is using 1 .
Therefore, options C and D are correct.
NEW QUESTION # 66
Your GRE tunnel is not transitioning to the Up status.
What would be the first step in troubleshooting the problem?
- A. Verify that the routing instance for GRE tunnels is created.
- B. Verify the status of the management routing instance.
- C. Verify that the status of the management interface is up.
- D. Verify tunnel endpoint reachability.
Answer: D
NEW QUESTION # 67
Which two statements are correct about behavior aggregate (BA) classifiers in Junos OS CoS?
(Choose two.)
- A. A BA classifier examines multiple fields, including source and destination address, similar to a multifield classifier.
- B. BA classifiers are applied on ingress interfaces.
- C. A BA classifier assigns forwarding class and loss priority based on a field in the packet header, such as DSCP or IEEE 802.1p.
- D. BA classifiers can only be used for egress traffic shaping.
Answer: B,C
Explanation:
A behavior aggregate (BA) classifier assigns a forwarding class and loss priority to incoming packets based on a single field in the packet header, such as the DSCP value in IP packets or the IEEE 802.1p CoS bits in Ethernet frames. BA classifiers are applied on ingress interfaces to determine how a packet will be treated as it moves through the device.
NEW QUESTION # 68
Exhibit.
Which router will become the OSPF BDR if all routers are powered on at the same time?
- A. R3
- B. R4
- C. R1
- D. R2
Answer: B
Explanation:
Explanation
OSPF DR/BDR election is a process that occurs on multi-access data links. It is intended to select two OSPF nodes: one to be acting as the Designated Router (DR), and another to be acting as the Backup Designated Router (BDR).The DR and BDR are responsible for generating network LSAs for the multi-access network and synchronizing the LSDB with other routers on the same network1.
The DR/BDR election is based on two criteria: the OSPF priority and the router ID. The OSPF priority is a value between 0 and 255 that can be configured on each interface participating in OSPF. The default priority is
1. A priority of 0 means that the router will not participate in the election and will never become a DR or BDR. The router with the highest priority will become the DR, and the router with the second highest priority will become the BDR. If there is a tie in priority, then the router ID is used as a tie-breaker. The router ID is a
32-bit number that uniquely identifies each router in an OSPF domain.It can be manually configured or automatically derived from the highest IP address on a loopback interface or any active interface2.
In this scenario, all routers have the same priority of 1, so the router ID will determine the outcome of the election. The router IDs are shown in the exhibit as RID values. The highest RID belongs to R4 (10.10.10.4), so R4 will become the DR. The second highest RID belongs to R3 (10.10.10.3), so R3 will become the BDR.
References:
1:OSPF DR/BDR Election: Process, Configuration, and Tuning2:OSPF Designated Router (DR) and Backup Designated Router (BDR)
NEW QUESTION # 69
Which two statements correctly describe RSTP port roles? (Choose two.)
- A. The backup port is used as a backup for the root port.
- B. The root port is responsible for forwarding data to the root bridge.
- C. The alternate port is a standby port for an edge port.
- D. The designated port forwards data to the downstream network segment or device.
Answer: B,D
Explanation:
In Rapid Spanning Tree Protocol (RSTP), there are several port roles that determine the behavior of the port in the spanning tree 1 .
Option A suggests that the designated port forwards data to the downstream network segment or device. This is correct because the designated port is the port on a network segment that has the best path to the root bridge
1 . It's responsible for forwarding frames towards the root bridge and sending configuration messages into its segment 1 .
Option D suggests that the root port is responsible for forwarding data to the root bridge. This is also correct because the root port is always the link directly connected to the root bridge, or the shortest path to the root bridge 1 . It's used to forward traffic towards the root bridge 1 .
Therefore, options A and D are correct.
NEW QUESTION # 70
You want to use filter-based forwarding (FBF) to forward traffic sourced from subnet 10.0.0.0/24 to a specific destination.
Which two routing instance types would enable you to accomplish this task? (Choose two.)
- A. virtual routing and forwarding
- B. virtual switch
- C. forwarding
- D. virtual router
Answer: C,D
NEW QUESTION # 71
Which two elements are used to create the STP bridge ID? (Choose two.)
- A. the bridge priority value
- B. the port cost
- C. the system MAC address
- D. the root port number
Answer: A,C
NEW QUESTION # 72
Which mechanism is used to share routes between routing tables?
- A. forwarding instances
- B. routing instances
- C. filter-based forwarding
- D. RIB groups
Answer: D
NEW QUESTION # 73
You are asked to create a default route that will be advertised to your internal OSPF neighbors. You have three upstream connections to the Internet and you must ensure that when available, all traffic uses ISP1 as your primary connection and only uses ISP2 and ISP3 when ISP1 is not available.
Which solution should you implement in this scenario?
- A. Create a default generate route that includes an import policy to match BGP routes from ISP1 and assign a preference value of four or less.
- B. Create a default static route with each neighbor address as the next hop.
- C. Create a default aggregated route.
- D. Create a default static route with ISP1 ' s address as the next hop while specifying the addresses for ISP2 and ISP3 as qualified next hops with a preference value of six or higher.
Answer: D
Explanation:
The solution that should be implemented in this scenario is to create a default generate route that includes an import policy to match BGP routes from ISP1 and assign a preference value of four or less. This way, the default route will be advertised to the internal OSPF neighbors only when there is a BGP route from ISP1 in the routing table, and it will have a higher preference than any other default route from ISP2 or ISP3. If ISP1 is not available, the default generate route will be withdrawn and the traffic will use the next available default route from ISP2 or ISP3.
Option A is incorrect because creating a default static route with ISP1's address as the next hop while specifying the addresses for ISP2 and ISP3 as qualified next hops with a preference value of six or higher will not ensure that the default route is advertised to the internal OSPF neighbors only when ISP1 is available. The default static route will always be in the routing table regardless of the availability of ISP1, and it will have a lower preference than any other default route from ISP2 or ISP3.
Option C is incorrect because creating a default static route with each neighbor address as the next hop will not ensure that all traffic uses ISP1 as the primary connection and only uses ISP2 and ISP3 when ISP1 is not available. The default static route will always be in the routing table regardless of the availability of ISP1, and it will load balance the traffic among the three ISPs.
Option D is incorrect because creating a default aggregated route will not ensure that the default route is advertised to the internal OSPF neighbors only when ISP1 is available. The default aggregated route will always be in the routing table regardless of the availability of ISP1, and it will not have any preference value associated with it. References:
* Enterprise Routing and Switching, Specialist (JNCIS-ENT) - Juniper Networks
* Enterprise Routing and Switching, Specialist (JNCIS-ENT) - Juniper Networks
NEW QUESTION # 74
You enable persistent MAC learning on your Juniper switch. In this scenario, which statement is correct?
- A. You can only enable persistent MAC learning on an interface in access mode.
- B. You can enable persistent MAC learning on an interface where MAC learning is disabled.
- C. You can enable persistent MAC learning on an interface that is part of a redundant trunk group.
- D. You can only enable persistent MAC learning on an interface on which 802.1x authentication is configured.
Answer: A
NEW QUESTION # 75
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