Get May-2024 Dumps to Pass your JN0-351 Exam with 100% Real Questions and Answers [Q25-Q47]

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Get May-2024 Dumps to Pass your JN0-351 Exam with 100% Real Questions and Answers

Updated Exam JN0-351 Dumps with New Questions

Juniper JN0-351 Exam Syllabus Topics:

Topic	Details
Topic 1	Describe the concepts, benefits, operations Demonstrate knowledge how to configure, monitor
Topic 2	Identify the concepts, benefits, applications Demonstrate knowledge of how to configure, monitor
Topic 3	Describe the concepts, operations, or functionalities of IS-IS Describe the concepts, operations, or functionalities of OSPF
Topic 4	Demonstrate knowledge how to configure, monitor Port security, including MAC limiting, DHCP snooping
Topic 5	Describe the concepts, benefits, or functionalities of VLANs STP and Rapid Spanning Tree Protocol (RSTP) concepts
Topic 6	Demonstrate knowledge of how to configure, monitor, or troubleshoot BGP Demonstrate knowledge of how to configure, monitor, or troubleshoot IP tunnels

Q25. Exhibit

Referring to the exhibit, which statement is correct?

The local device is using a bridge priority of 4k.

The root bridge is using a bridge priority of 4k.

The root bridge has not been elected for this RSTP topology.

The local device is the root bridge for this RSTP topology.

Q26. Exhibit

You have configured a GRE tunnel. To reduce the risk of dropping traffic, you have configured a keepalive OAM probe to monitor the state of the tunnel; however, traffic drops are still occurring.
Referring to the exhibit, what is the problem?

For GRE tunnels, the OAM protocol requires that the BFD protocols also be used.

The “event link-adjacency-loss” option must be set.

LLDP needs to be removed from the gr-1/1/10.1 interface.

The hold-time value must be two times the keepalive-time value

Explanation
A keepalive OAM probe is a mechanism that can be used to monitor the state of a GRE tunnel and detect any failures in the tunnel path. A keepalive OAM probe consists of sending periodic packets from one end of the tunnel to the other and expecting a reply. If no reply is received within a specified time, the tunnel is considered down and the line protocol of the tunnel interface is changed to down1.
To configure a keepalive OAM probe for a GRE tunnel, you need to specify two parameters: the keepalive-time and the hold-time. The keepalive-time is the interval between each keepalive packet sent by the local router. The hold-time is the maximum time that the local router waits for a reply from the remote router before declaring the tunnel down2.
According to the Juniper Networks documentation, the hold-time value must be two times the keepalive-time value for a GRE tunnel2. This is because the hold-time value must account for both the round-trip time of the keepalive packet and the processing time of the remote router. If the hold-time value is too small, it may cause false positives and unnecessary tunnel flaps.
In the exhibit, the configuration shows that the keepalive-time is set to 10 seconds and the hold-time is set to
15 seconds for the gr-1/1/10.1 interface. This means that the local router will send a keepalive packet every 10 seconds and will wait for 15 seconds for a reply from the remote router. However, this hold-time value is not two times the keepalive-time value, which violates the recommended configuration. This may cause traffic drops if the remote router takes longer than 15 seconds to reply.
Therefore, option D is correct, because the hold-time value must be two times the keepalive-time value for a GRE tunnel. Option A is incorrect, because BFD is not required for GRE tunnels; BFD is another protocol that can be used to monitor tunnels, but it is not compatible with GRE keepalives3. Option B is incorrect, because the “event link-adjacency-loss” option is not related to GRE tunnels; it is an option that can be used to trigger an action when a link goes down4. Option C is incorrect, because LLDP does not need to be removed from the gr-1/1/10.1 interface; LLDP is a protocol that can be used to discover neighboring devices and their capabilities, but it does not interfere with GRE tunnels5.
References:
1: Configuring Keepalive Time and Hold time for a GRE Tunnel Interface 2: keepalive | Junos OS | Juniper Networks 3: Configuring Bidirectional Forwarding Detection 4: event link-adjacency-loss | Junos OS | Juniper Networks 5: Understanding Link Layer Discovery Protocol

Q27. Which two statements about BGP facilitate the prevention of routing loops between two autonomous systems?
(Choose two.)

EBGP routers will append their AS number when advertising routes to their neighbors.

EBGP routers will only accept routes that contain their own AS number in the AS_PATH.

EBGP routers will drop routes that contain their own AS number in the AS_PATH

EBGP routers will prepend their AS number when advertising routes to their neighbors

Q28. Exhibit

Your ISP is announcing a default route to both R1 and R2. You want your network routers to forward all Internet traffic through the R1 device Which BGP attribute would you use?

MED

next-hop

local preference

origin

Q29. Which statement is correct about IP-IP tunnels?

IP-IP tunnels only support encapsulating IP traffic.

IP-IP tunnels only support encapsulating non-IP traffic.

The TTL in the inner packet is decremented during transit to the tunnel endpoint.

There are 24 bytes of overhead with IP-IP encapsulation.

Q30. Which three protocols support BFD? (Choose three.)

RSTP

BGP

OSPF

LACP

FTP

Explanation
BFD is a protocol that can be used to quickly detect failures in the forwarding path between two adjacent routers or switches. BFD can be integrated with various routing protocols and link aggregation protocols to provide faster convergence and fault recovery.
According to the Juniper Networks documentation, the following protocols support BFD on Junos OS devices1:
BGP: BFD can be used to monitor the connectivity between BGP peers and trigger a session reset if a failure is detected. BFD can be configured for both internal and external BGP sessions, as well as for IPv4 and IPv6 address families2.
OSPF: BFD can be used to monitor the connectivity between OSPF neighbors and trigger a state change if a failure is detected. BFD can be configured for both OSPFv2 and OSPFv3 protocols, as well as for point-to-point and broadcast network types3.
LACP: BFD can be used to monitor the connectivity between LACP members and trigger a link state change if a failure is detected. BFD can be configured for both active and passive LACP modes, as well as for static and dynamic LAGs4.
Other protocols that support BFD on Junos OS devices are:
IS-IS: BFD can be used to monitor the connectivity between IS-IS neighbors and trigger a state change if a failure is detected. BFD can be configured for both level 1 and level 2 IS-IS adjacencies, as well as for point-to-point and broadcast network types.
RIP: BFD can be used to monitor the connectivity between RIP neighbors and trigger a route update if a failure is detected. BFD can be configured for both RIP version 1 and version 2 protocols, as well as for IPv4 and IPv6 address families.
VRRP: BFD can be used to monitor the connectivity between VRRP routers and trigger a priority change if a failure is detected. BFD can be configured for both VRRP version 2 and version 3 protocols, as well as for IPv4 and IPv6 address families.
The protocols that do not support BFD on Junos OS devices are:
RSTP: RSTP is a spanning tree protocol that provides loop prevention and rapid convergence in layer 2 networks. RSTP does not use BFD to detect link failures, but relies on its own hello mechanism that sends BPDU packets every 2 seconds by default.
FTP: FTP is an application layer protocol that is used to transfer files between hosts over a TCP connection. FTP does not use BFD to detect connection failures, but relies on TCP’s own retransmission and timeout mechanisms.
References:
1: [Configuring Bidirectional Forwarding Detection] 2: [Configuring Bidirectional Forwarding Detection for BGP] 3: [Configuring Bidirectional Forwarding Detection for OSPF] 4: [Configuring Bidirectional Forwarding Detection for Link Aggregation Control Protocol] : [Configuring Bidirectional Forwarding Detection for IS-IS] : [Configuring Bidirectional Forwarding Detection for RIP] : [Configuring Bidirectional Forwarding Detection for VRRP] : [Understanding Rapid Spanning Tree Protocol] : [Understanding FTP]

Q31. You are asked to create a new firewall filter to evaluate Layer 3 traffic that is being sent between VLANs. In this scenario, which two statements are correct? (Choose two.)

You should create a family Ethernet-switching firewall filter with the appropriate match criteria and actions.

You should apply the firewall filter to the appropriate VLAN.

You should create a family inet firewall filter with the appropriate match criteria and actions.

You should apply the firewall filter to the appropriate IRB interface.

Explanation
A firewall filter is a configuration that defines the rules that determine whether to forward or discard packets at specific processing points in the packet flow. A firewall filter can also modify the attributes of the packets, such as priority, marking, or logging. A firewall filter can be applied to various interfaces, protocols, or routing instances on a Juniper device1.
A firewall filter has a family attribute, which specifies the type of traffic that the filter can evaluate. The family attribute can be one of the following: inet, inet6, mpls, vpls, iso, or ethernet-switching2. The family inet firewall filter is used to evaluate IPv4 traffic, which is the most common type of Layer 3 traffic on a network.
To create a family inet firewall filter, you need to specify the appropriate match criteria and actions for each term in the filter. The match criteria can include various fields in the IPv4 header, such as source address, destination address, protocol, port number, or DSCP value. The actions can include accept, discard, reject, count, log, policer, or next term3.
To apply a firewall filter to Layer 3 traffic that is being sent between VLANs, you need to apply the filter to the appropriate IRB interface. An IRB interface is an integrated routing and bridging interface that provides Layer 3 functionality for a VLAN on a Juniper device. An IRB interface has an IP address that acts as the default gateway for the hosts in the VLAN. An IRB interface can also participate in routing protocols and forward packets to other VLANs or networks4.
Therefore, option C is correct, because you should create a family inet firewall filter with the appropriate match criteria and actions. Option D is correct, because you should apply the firewall filter to the appropriate IRB interface.
Option A is incorrect, because you should not create a family ethernet-switching firewall filter with the appropriate match criteria and actions. A family ethernet-switching firewall filter is used to evaluate Layer 2 traffic on a Juniper device. A family ethernet-switching firewall filter can only match on MAC addresses or VLAN IDs, not on IP addresses or protocols5.
Option B is incorrect, because you should not apply the firewall filter to the appropriate VLAN. A VLAN is a logical grouping of hosts that share the same broadcast domain on a Layer 2 network. A VLAN does not have an IP address or routing capability. A firewall filter cannot be applied directly to a VLAN; it must be applied to an interface that belongs to or connects to the VLAN6.
References:
1: Firewall Filters Overview 2: Configuring Firewall Filters 3: Configuring Firewall Filter Match Conditions and Actions 4: Understanding Integrated Routing and Bridging Interfaces 5: Configuring Ethernet-Switching Firewall Filters 6: Understanding VLANs

Q32. Which two statements about redundant trunk groups on EX Series switches are correct? (Choose two.)

Redundant trunk groups use spanning tree to provide loop-free redundant uplinks.

Redundant trunk groups load balance traffic across two designated uplink interfaces.

Layer 2 control traffic is permitted on the secondary link.

If the active link fails, then the secondary link automatically takes over.

Q33. Two routers share the same highest priority and start time.

In this situation, what is evaluated next when determining the designated router? The router with the lowest router ID become the DR.

The router with the highest router ID becomes the DR

The routers perform another DR election.

The router with the highest MAC address become the DR

Q34. What are two characteristics of RSTP alternate ports? (Choose two.)

RSTP alternate ports provide an alternate higher cost path to the root bridge.

RSTP alternate ports provide an alternate lower cost path to the root bridge.

RSTP alternate ports block traffic while receiving superior BPDUs from a neighboring switch.

RSTP alternate ports are active ports used to forward frames toward the root bridge.

Q35. You want to use filter-based forwarding (FBF) on your Internet peering router to load-balance traffic to two directly connected ISPs based on the source address.
Which two statements are correct in this scenario? (Choose two.)

FBF uses the no-forwarding routing instance type.

FBF uses the forwarding routing instance type.

RIB groups are used to copy routes from the inet. o routing table.

RIB groups are used to hide routes in the inet. 0 routing table.

Q36. Which two statements are true about the default VLAN on Juniper switches? (Choose two.)

The default VLAN is set to a VLAN ID of 1 by default

The default VLAN ID is not assigned to any interface.

The default VLAN ID is not visible.

The default VLAN ID can be changed.

Q37. You are receiving multiple BGP routes from an upstream neighbor and only want to advertise a single summarized prefix to your internal OSPF neighbors. This route should only be advertised when you are receiving these BGP routes from this neighbor.
In this scenario, which type of route should you create?

aggregate route

static route using the resolve feature

generate route

static route using qualified next hops

Q38. Exhibit.

Which router will become the OSPF BDR if all routers are powered on at the same time?

Q39. Which two statements are correct about using firewall filters on EX Series switches? (Choose two.)

You can deploy only stateless firewall filters on an EX Series switch.

You can only apply firewall filters to Layer 2 traffic on an EX Series switch.

You can apply firewall filters to both Layer 2 and Layer 3 traffic on an EX Series switch.

You can deploy both stateless and stateful firewall filters on an EX Series switch.

Q40. Which two statements are correct about tunnels? (Choose two.)

BFD cannot be used to monitor tunnels.

Tunnel endpoints must have a valid route to the remote tunnel endpoint.

IP-IP tunnels are stateful.

Tunnels add additional overhead to packet size.

Explanation
A tunnel is a connection between two computer networks, in which data is sent from one network to another through an encrypted link. Tunnels are commonly used to secure data communications between two networks or to connect two networks that use different protocols.
Option B is correct, because tunnel endpoints must have a valid route to the remote tunnel endpoint. A tunnel endpoint is the device that initiates or terminates a tunnel connection. For a tunnel to be established, both endpoints must be able to reach each other over the underlying network. This means that they must have a valid route to the IP address of the remote endpoint1.
Option D is correct, because tunnels add additional overhead to packet size. Tunnels work by encapsulating packets: wrapping packets inside of other packets. This means that the original packet becomes the payload of the surrounding packet, and the surrounding packet has its own header and trailer. The header and trailer of the surrounding packet add extra bytes to the packet size, which is called overhead. Overhead can reduce the efficiency and performance of a network, as it consumes more bandwidth and processing power2.
Option A is incorrect, because BFD can be used to monitor tunnels. BFD is a protocol that can be used to quickly detect failures in the forwarding path between two adjacent routers or switches. BFD can be integrated with various routing protocols and link aggregation protocols to provide faster convergence and fault recovery.
BFD can also be used to monitor the connectivity of tunnels, such as GRE, IPsec, or MPLS.
Option C is incorrect, because IP-IP tunnels are stateless. IP-IP tunnels are a type of tunnels that use IP as both the encapsulating and encapsulated protocol. IP-IP tunnels are simple and easy to configure, but they do not provide any security or authentication features. IP-IP tunnels are stateless, which means that they do not keep track of the state or status of the tunnel connection. Stateless tunnels do not require any signaling or negotiation between the endpoints, but they also do not provide any error detection or recovery mechanisms.
References:
1: What is Tunneling? | Tunneling in Networking 2: What Is Tunnel In Networking, Its Types, And Its Benefits? : [Configuring Bidirectional Forwarding Detection] : [IP-IP Tunneling]

Q41. Which statement is correct about graceful Routing Engine switchover (GRES)?

The PFE restarts and the kernel and interface information is lost.

GRES has a helper mode and a restarting mode.

When combined with NSR, routing is preserved and the new master RE does not restart rpd.

With no other high availability features enabled, routing is preserved and the new master RE does not restart rpd.

Q42. After receiving a BGP route, which two conditions are verified by the receiving router to ensure that the received route is valid? (Choose two)

The AS-path length is greater than 0.

The loops do not exist.

The next hop is reachable.

The local preference is greater than 0.

Q43. Exhibit

What does the * indicate in the output shown in the exhibit?

The switch ports have a router attached.

The interface is down.

The interface is active.

All interfaces have elected a root bridge.

Q44. You are configuring an IS-IS IGP network and do not see the IS-IS adjacencies established. In this scenario, what are two reasons for this problem? (Choose two.)

MTU is not at least 1492 bytes.

IP subnets are not a /30 address.

The Level 2 routers have mismatched areas.

The lo0 interface is not included as an IS-IS interface.

Q45. You are a network operator who wants to add a second ISP connection and remove the default route to the existing ISP You decide to deploy the BGP protocol in the network.
What two statements are correct in this scenario? (Choose two.)

IBGP updates the next-hop attribute to ensure reachability within an AS.

IBGP peers advertise routes received from EBGP peers to other IBGP peers.

IBGP peers advertise routes received from IBGP peers to other IBGP peers.

EBGP peers advertise routes received from IBGP peers to other EBGP peers.

Q46. You need to configure a LAG between your switches. In this scenario, which two statements are correct?
(Choose two.)

Duplex and speed settings are not required to match on both participating devices.

Duplex and speed settings are required to match on both participating devices.

Member links are not required to be contiguous ports.

Member links are required to be contiguous ports.

Q47. Which two types of tunnels are able to be created on all Junos devices? (Choose two.)

STP

GRE