JN0-351試験問題集でPDF問題とテストエンジン [Q18-Q41]

JN0-351試験問題集でPDF問題とテストエンジン

JN0-351問題集で必ず試験合格させる

質問 # 18
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.)

A. The Level 2 routers have mismatched areas.
B. MTU is not at least 1492 bytes.
C. The lo0 interface is not included as an IS-IS interface.
D. IP subnets are not a /30 address.

正解：B、C

解説：
Explanation
Option A suggests that the MTU is not at least 1492 bytes. This is correct because IS-IS requires a minimum MTU of 1492 bytes to establish adjacencies1. If the MTU is less than this, IS-IS adjacencies will not be established1.
Option D suggests that the lo0 interface is not included as an IS-IS interface. This is also correct because the loopback interface (lo0) is typically used as the router ID in IS-IS1. If the loopback interface is not included in IS-IS, it could prevent IS-IS adjacencies from being established1.
Therefore, options A and D are correct.

質問 # 19
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?

A. The force-version must be removed.
B. The max-age must be increased to 20
C. The hello-time must be increased.
D. The bridge priority for EX-4 must be set at 4000.

正解：A

解説：
The exhibit shows the configuration of RSTP on EX-4, which has the command force-version stp. This command forces the switch to use the legacy STP protocol instead of RSTP, even though the switch supports RSTP1. This means that EX-4 will not be able to take advantage of the faster convergence and enhanced features of RSTP, such as edge ports, link type, and proposal/agreement sequence2.
The other switches in the network are likely to be running RSTP, as it is the default protocol for EX Series switches3. Therefore, there will be a compatibility issue between EX-4 and the other switches, which will result in longer convergence times and suboptimal performance. The switch will also generate a warning message that says "Warning: STP version mismatch with neighbor" when it receives a BPDU from a RSTP neighbor1.
To solve this problem, the force-version command must be removed from EX-4, so that it can run RSTP natively and interoperate with the other switches in the network. This will enable faster convergence and better stability for the network topology. To remove the command, you can use the delete protocols rstp force-version command in configuration mode1.

質問 # 20
What is a purpose of using a spanning tree protocol?

A. to tunnel Ethernet frames
B. to look up MAC addresses
C. to route IP packets
D. to eliminate broadcast storms

正解：D

解説：
A broadcast storm is a network condition where a large number of broadcast packets are sent and received by multiple devices, causing congestion and performance degradation1. A broadcast storm can occur when there are loops in the network topology, meaning that there are multiple paths between two devices2.
A spanning tree protocol is a network protocol that prevents loops from being formed when switches or bridges are interconnected via multiple paths. It does this by creating a logical tree structure that spans all the devices in the network, and disabling or blocking the links that are not part of the tree, leaving a single active path between any two devices3.
By eliminating loops, a spanning tree protocol also eliminates broadcast storms, as broadcast packets will not be forwarded endlessly along the looped paths. Instead, broadcast packets will be sent only along the tree structure, reaching each device once and avoiding congestion3.

質問 # 21
Which two statements are correct about generated routes? (Choose two.)

A. Generated routes cannot be redistributed into dynamic routing protocols.
B. Generated routes show a next hop in the routing table.
C. Generated routes require a contributing route.
D. Generated routes appear in the routing table as static routes

正解：B、C

解説：
A is correct because generated routes require a contributing route. A contributing route is a route that matches the destination prefix of the generated route and has a valid next hop1. A generated route is only installed in the routing table if there is at least one contributing route available2. This ensures that the generated route is reachable and useful. If there is no contributing route, the generated route is not added to the routing table2.
B is correct because generated routes show a next hop in the routing table. A generated route inherits the next hop of its primary contributing route, which is the most preferred route among all the contributing routes2. The next hop of the generated route can be either an IP address or an interface name, depending on the type of the contributing route2. The next hop of the generated route can also be modified by a routing policy3.

質問 # 22
What are two characteristics of RSTP alternate ports? (Choose two.)

A. RSTP alternate ports provide an alternate lower cost path to the root bridge.
B. RSTP alternate ports block traffic while receiving superior BPDUs from a neighboring switch.
C. RSTP alternate ports provide an alternate higher cost path to the root bridge.
D. RSTP alternate ports are active ports used to forward frames toward the root bridge.

正解：B、C

解説：
A is correct because RSTP alternate ports block traffic while receiving superior BPDUs from a neighboring switch. An alternate port is a backup port for a root port, which means it receives better BPDUs from another bridge than the current root port1. However, an alternate port does not forward any traffic, as it is in a discarding state2. It only listens to BPDUs and waits for the root port to fail. If the root port fails, the alternate port can immediately transition to a forwarding state and become the new root port1.
C is correct because RSTP alternate ports provide an alternate higher cost path to the root bridge. An alternate port is selected based on the same criteria as the root port, which are the lowest bridge ID, the lowest path cost, the lowest sender port ID, and the lowest receiver port ID3. However, an alternate port receives a higher cost BPDU than the root port, otherwise it would be the root port itself1. Therefore, an alternate port provides an alternate higher cost path to the root bridge than the root port.

質問 # 23
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?

A. The "event link-adjacency-loss" option must be set.
B. LLDP needs to be removed from the gr-1/1/10.1 interface.
C. The hold-time value must be two times the keepalive-time value
D. For GRE tunnels, the OAM protocol requires that the BFD protocols also be used.

正解：C

解説：
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

質問 # 24
Exhibit.

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

A. 128.0.0.1
B. 172.23.12.100
C. 172.23.11.10
D. 10.210.20.233

正解：B

解説：
Explanation
The management IP address of a device is the IP address that is used to access the device for configuration and monitoring purposes. It is usually assigned to a dedicatedmanagement interface that is separate from the data interfaces. The management interface can be accessed via SSH, Telnet, HTTP, or other protocols.
In the exhibit, the list of interfaces and their statuses shows that the management interface isme0. This interface has an admin status ofup, a protocol status ofinet, a local address of172.23.12.100/24, and a remote address ofunspecified. This means that the me0 interface is active, has an IPv4 address assigned, and is not connected to another device.
Therefore, the management IP address of the device shown in the exhibit is172.23.12.100.
References:
[Management Interfaces Overview] : [Displaying Interface Status Information]

質問 # 25
What are two characteristics of RSTP alternate ports? (Choose two.)

A. RSTP alternate ports provide an alternate lower cost path to the root bridge.
B. RSTP alternate ports block traffic while receiving superior BPDUs from a neighboring switch.
C. RSTP alternate ports provide an alternate higher cost path to the root bridge.
D. RSTP alternate ports are active ports used to forward frames toward the root bridge.

正解：B、C

質問 # 26
Refer to the exhibit.

Referring to the output shown in the exhibit, which statement is correct?

A. An area ID mismatch exists between the OSPF neighbors
B. The state is normal for a DRother neighbor
C. An MTU mismatch exists between the OSPF neighbors.
D. The state is normal for a DR neighbor.

正解：B

解説：
Explanation
In OSPF, the state of the neighbor relationship is determined by the exchange of OSPF packets between routers1. The state "2Way" as shown in the exhibit indicates that bi-directional communication has been established between the two OSPF routers1. This is the normal state for a neighbor that is not the Designated Router (DR) or Backup Designated Router (BDR) on a broadcast, non-broadcast multi-access (NBMA), or point-to-multipoint network1. These neighbors are often referred to as "DRothers"1. Therefore, option B is correct.

質問 # 27
Which two statements are correct about using firewall filters on EX Series switches? (Choose two.)

A. You can only apply firewall filters to Layer 2 traffic on an EX Series switch.
B. You can deploy only stateless firewall filters on an EX Series switch.
C. You can deploy both stateless and stateful firewall filters on an EX Series switch.
D. You can apply firewall filters to both Layer 2 and Layer 3 traffic on an EX Series switch.

正解：B、D

解説：
A is correct because you can deploy only stateless firewall filters on an EX Series switch. A stateless firewall filter is a filter that evaluates each packet individually based on the header information, such as source and destination addresses, protocol, and port numbers1. A stateless firewall filter does not keep track of the state or context of a packet flow, such as the sequence number, flags, or sessioninformation1. EX Series switches support only stateless firewall filters, which are also called access control lists (ACLs) or packet filters2.
C is correct because you can apply firewall filters to both Layer 2 and Layer 3 traffic on an EX Series switch. Layer 2 traffic is traffic that is switched within a VLAN or a bridge domain, while Layer 3 traffic is traffic that is routed between VLANs or networks3. EX Series switches support three types of firewall filters: port (Layer 2) firewall filters, VLAN firewall filters, and router (Layer 3) firewall filters4. You can apply these filters to different interfaces and directions to control the traffic entering or exiting the switch.

質問 # 28
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.)

A. The interface is configured as a disabled port.
B. The interface is configured as a trunk port.
C. MAC limiting is enabled on the interface.
D. Dynamic ARP inspection is enabled on the interface.

正解：A、B

解説：
A is correct because the interface is configured as a disabled port. A disabled port does not forward any traffic, including DHCP packets. Therefore, DHCP snooping cannot learn any MAC addresses or lease information from a disabled port1.
C is correct because the interface is configured as a trunk port. By default, all trunk ports on the switch are trusted for DHCP snooping2. This means that DHCP snooping does not inspect or filter any DHCP packets received on a trunk port. Therefore, DHCP snooping does not add any entries to the snooping database for a trunk port2.

質問 # 29
Which two BGP attributes must be supported by all BGP implementations and must be included in every update? (Choose two.)

A. community
B. MED
C. next hop
D. AS path

正解：C、D

解説：
Explanation
BGP attributes are properties that BGP uses for route advertisement, path selection, and loop prevention1. There are four categories of BGP attributes123:
Well-known mandatory: Must be recognized by all BGP routers, present in all BGP updates, and passed on to other BGP routers123.
Well-known discretionary: Supported by all BGP implementations, and are optionally included in BGP updates1.
Optional transitive: May not be supported by all implementations of BGP1.
Optional non-transitive: May not be supported by all implementations of BGP1.
The well-known mandatory attributes must be supported by all BGP implementations and must be included in every update123. These include the AS path and next hop attributes23. Therefore, options A and C are correct.

質問 # 30
What is the default keepalive time for BGP?

A. 30 seconds
B. 90 seconds
C. 60 seconds
D. 10 seconds

正解：C

解説：
Explanation
The default keepalive time for BGP is 60 seconds1. The keepalive time is the interval at which BGP sends keepalive messages to maintain the connection with its peer1. If the keepalive message is not received within the hold time, the connection is considered lost1. By default, the hold time is three times the keepalive time, which is 180 seconds1.

質問 # 31
You need to configure a LAG between your switches. In this scenario, which two statements are correct?
(Choose two.)

A. Member links are required to be contiguous ports.
B. Duplex and speed settings are required to match on both participating devices.
C. Duplex and speed settings are not required to match on both participating devices.
D. Member links are not required to be contiguous ports.

正解：B、D

解説：
B is correct because duplex and speed settings are required to match on both participating devices. According to the Juniper Networks documentation1, all the interfaces in a LAG must have the same speed and be in full-duplex mode. This ensures that the LAG can operate as a single logical link without any performance or compatibility issues.
C is correct because member links are not required to be contiguous ports. According to the Juniper Networks documentation2, you can group any Ethernet interfaces on a switch into a LAG, regardless of their physical location or slot number. This provides flexibility and scalability for configuring LAGs on switches.

質問 # 32
Exhibit

Referring to the exhibit, which two configuration changes must you apply for packets to reach from R1 to R3 using IS-IS? (Choose two.)

A. On R3 disable Level 2 on the ge-0/0/4 interface.
B. On R1, disable Level 2 on the ge-0/0/1 interface.
C. On R3 enable Level 1 on the ge-0/0/4 interface
D. On R1, enable Level 1 on the ge-0/0/1 interface.

正解：C、D

解説：
Explanation
A: On R1, enable Level 1 on the ge-0/0/1 interface. In IS-IS, both levels (Level 1 and Level 2) are enabled by default when you enable IS-IS on an interface1. Level 1 systems route within an area2. If the destination is outside an area, Level 1 systems route toward a Level 2 system2. Therefore, enabling Level 1 on the ge-0/0/1 interface on R1 would allow packets to reach from R1 to R3.
D: On R3 enable Level 1 on the ge-0/0/4 interface Similarly, enabling Level 1 on the ge-0/0/4 interface on R3 would allow packets to reach from R1 to R3.
These explanations are based on the IS-IS configuration documents and learning resources available at Juniper Networks1 and Cisco34.

質問 # 33
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 R1 is configured for AS 65400.
B. The routers are exchanging IPv4 routes.
C. The BGP session is not established.
D. Peer 10.32.1.2 is configured for AS 63645.

正解：A、C

解説：
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.

質問 # 34
Two routers share the same highest priority and start time.

A. The router with the highest router ID becomes the DR
B. The routers perform another DR election.
C. The router with the highest MAC address become the DR
D. In this situation, what is evaluated next when determining the designated router? The router with the lowest router ID become the DR.

正解：A

解説：
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.

質問 # 35
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 designated port forwards data to the downstream network segment or device.
C. The root port is responsible for forwarding data to the root bridge.
D. The alternate port is a standby port for an edge port.

正解：B、C

解説：
Explanation
In Rapid Spanning Tree Protocol (RSTP), there are several port roles that determine the behavior of the port in the spanning tree1.
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 bridge1. It's responsible for forwarding frames towards the root bridge and sending configuration messages into its segment1.
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 bridge1. It's used to forward traffic towards the root bridge1.
Therefore, options A and D are correct.

質問 # 36
Which two statements are true about the default VLAN on Juniper switches? (Choose two.)

A. The default VLAN ID can be changed.
B. The default VLAN ID is not assigned to any interface.
C. The default VLAN ID is not visible.
D. The default VLAN is set to a VLAN ID of 1 by default

正解：A、D

解説：
Explanation
On Juniper switches, the default VLAN is set to a VLAN ID of 1 by default12. This means that all interfaces on the switch are members of VLAN 1 until they are specifically assigned to another VLAN12. Therefore, option A is correct.
The default VLAN ID can be changed12. This allows network administrators to configure the switch to use a different VLAN as the default, if necessary12. Therefore, option D is correct.

質問 # 37
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.)

A. IBGP peers advertise routes received from IBGP peers to other IBGP peers.
B. IBGP updates the next-hop attribute to ensure reachability within an AS.
C. IBGP peers advertise routes received from EBGP peers to other IBGP peers.
D. EBGP peers advertise routes received from IBGP peers to other EBGP peers.

正解：B、C

解説：
A is correct because IBGP updates the next-hop attribute to ensure reachability within an AS. This is because the next-hop attribute is the IP address of the router that advertises the route to a BGP peer. If the next-hop attribute is not changed by IBGP, it would be the IP address of an external router, which may not be reachable by all routers within the AS. Therefore, IBGP updates the next-hop attribute to the IP address of the router that received the route from an EBGP peer1.
B is correct because IBGP peers advertise routes received from EBGP peers to other IBGP peers. This is because BGP follows the rule of advertising only the best route to a destination, and EBGP routes have a higher preference than IBGP routes. Therefore, IBGP peers advertise routes learned from an EBGP peer to all BGP peers, including both EBGP and IBGP peers1.

質問 # 38
Which statement is correct about the IS-IS ISO NET address?

A. An ISO NET address defined with a system ID of 0000.0000.0000 must be selected as the DIS.
B. The Area ID must match on all devices within a L2 area.
C. An ISO NET address must be unique for each device in the network.
D. You can only define a single ISO NET address per device.

正解：C

解説：
An ISO NET address is a type of network address used by the IS-IS routing protocol. It identifies a point of connection to the network, such as a router interface, and is also called a Network Service Access Point (NSAP)1.
An ISO NET address consists of three parts: an area ID, a system ID, and a selector2. The area ID identifies the IS-IS area to which the device belongs. The system ID uniquely identifies the device within the area. The selector identifies a specific service or function on the device, such as routing or management2.
An ISO NET address must be unique for each device in the network, because it is used by IS-IS to establish adjacencies, exchange routing information, and compute shortest paths2. If two devices have the same ISO NET address, they will not be able to communicate with each other or with other devices in the network. Therefore, it is important to assign different ISO NET addresses to each device in the network.

質問 # 39
Exhibit.

The ispi _ inet. 0 route table has currently no routes in it.
What will happen when you commit the configuration shown on the exhibit?

A. The ISPI . inet. 0 route table will be completely overwritten by the inet. o route table.
B. The inet. 0 route table will be imported into the ispi . inet. 0 route table.
C. The inet. 0 route table will be completely overwritten by the ispi . inet. 0 route table.
D. The ISPI . inet. 0 route table will be imported into the inet. 0 route table.

正解：B

解説：
Explanation
The configuration shown in the exhibit is an example of a routing instance of type virtual-router. A routing instance is a collection of routing tables, interfaces, and routing protocol parameters that create a separate routing domain on a Juniper device1. A virtual-router routing instance allows administrators to divide a device into multiple independent virtual routers, each with its own routing table2.
The configuration also includes a rib-group statement, which is used to import routes from one routing table to another. A rib-group consists of an import-rib statement, which specifies the source routing table, and an export-rib statement, which specifies the destination routing table.
In this case, the rib-group name is inet-to-ispi, and the import-rib statement specifies inet.0 as the source routing table. The export-rib statement specifies ispi.inet.0 as the destination routing table. This means that the routes from inet.0 will be imported into ispi.inet.0.
Therefore, the correct answer is B. The inet.0 route table will be imported into the ispi.inet.0 route table.
References:
1: Routing Instances Overview 2: Virtual Routing Instances : [rib-group (Routing Options)]

質問 # 40
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?

A. MED
B. local preference
C. next-hop
D. origin

正解：B

解説：
Explanation
The BGP attribute that you would use to forward all Internet traffic through the R1 device is the local preference1.
The local preference is an attribute that is used within an autonomous system (AS) and exchanged between iBGP routers1. It is used to select an exit point from the AS1. The path with the highest local preference is preferred1. By setting a higher local preference for the routes received from R1, you can make R1 the preferred exit point for all Internet traffic1.

質問 # 41
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合格させるJuniper JN0-351試験最速合格にはJPNTest：https://www.jpntest.com/shiken/JN0-351-mondaishu

JN0-351試験問題（更新されたのは2024年）100%リアル問題解答：https://drive.google.com/open?id=1RZI_PTGVkKRklcVtsbBhU8fMmZF5cuLY