Pass Your Exam Easily! JN0-351 Real Question Answers Updated on Oct 28, 2023 [Q34-Q56]

NO.34 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

NO.35 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.

NO.36 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.

NO.37 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]

NO.38 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.

NO.39 You have DHCP snooping enabled but no entries are automatically created in the snooping database for an interface on your EX Series switch. What are two reasons for the problem? (Choose two.)

The device that is connected to the interface has performed a DHCPRELEASE.

MAC limiting is enabled on the interface.

The device that is connected to the interface has a static IP address.

Dynamic ARP inspection is enabled on the interface.

NO.40 You implemented the MAC address limit feature with the shutdown action on all interfaces on your switch.
In this scenario, which statement is correct when a violation occurs?

By default, you must manually clear the violation for the interface to send and receive traffic again.

By default, the violation will automatically be cleared after 300 seconds and the interface will resume sending and receiving traffic for all learned devices.

By default, devices that are learned before the violation occurs are still allowed to send and receive traffic through the specific interface.

By default, the interface will continue to send and receive traffic for all connected devices after a violation has occurred.

NO.41 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.

NO.42 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.

NO.43 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

NO.44 Exhibit

You are troubleshooting an issue where traffic to 192.168.10.0/24 is being sent to R1 instead of your desired path through R2.
Referring to the exhibit, what is the reason for the problem?

R2’s route is not the best path due to loop prevention.

R2’s route is not the best path due to a lower origin code.

R1’s route is the best path due to a higher local preference

R1’s route is the best path due to the shorter AS path.

NO.45 Which statement is correct about the IS-IS ISO NET address?

An ISO NET address defined with a system ID of 0000.0000.0000 must be selected as the DIS.

An ISO NET address must be unique for each device in the network.

You can only define a single ISO NET address per device.

The Area ID must match on all devices within a L2 area.

NO.46 Exhibit

You are receiving the BGP route shown in the exhibit from four different upstream ISPs.
Referring to the exhibit, which ISP will be selected as the active path?

ISP1

ISP 3

ISP 4

ISP 2

NO.47 Exhibit.

What is the management IP address of the device shown in the exhibit?

10.210.20.233

172.23.12.100

128.0.0.1

172.23.11.10

NO.48 You deployed a new EX Series switch with DHCP snooping enabled and you do not see any entries in the snooping databases for an interface. Which two Juniper configurations for that interface caused this issue?
(Choose two.)

The interface is configured as a disabled port.

MAC limiting is enabled on the interface.

The interface is configured as a trunk port.

Dynamic ARP inspection is enabled on the interface.

NO.49 Exhibit.

You have configured the four EX Series switches with RSTP, as shown in the exhibit. You discover that whenever a link between switches goes up or down, the switches take longer than expected for RSTP to converge, using the default settings.
In this scenario, which action would solve the delay in RSTP convergence?

The hello-time must be increased.

The force-version must be removed.

The bridge priority for EX-4 must be set at 4000.

The max-age must be increased to 20

NO.50 Exhibit

Which command displays the output shown in the exhibit?

show route forwarding-table

show ethernet-switching table

show ethernet-switching table extensive

show route forwarding-table family ethernet-switching

NO.51 Which two mechanisms are part of building and maintaining a Layer 2 bridge table? (Choose two.)

blocking

flooding

learning

listening

NO.52 What is the maximum allowable MTU size for a default GRE tunnel without IPv4 traffic fragmentation?

1496 bytes

1480 bytes

1500 bytes

1476 bytes

NO.53 What is a purpose of using a spanning tree protocol?

to look up MAC addresses

to eliminate broadcast storms

to route IP packets

to tunnel Ethernet frames

NO.54 You are concerned about spoofed MAC addresses on your LAN.
Which two Layer 2 security features should you enable to minimize this concern? (Choose two.)

dynamic ARP inspection

IP source guard

DHCP snooping

static ARP

NO.55 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

NO.56 A new network requires multiple topology support. You decide to use IS-IS in this situation. Which three protocol topologies are supported in this scenario? (Choose three.)

IPsec

anycast

IPv6

multicast

IPv4

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