View Full Juniper JN0-364  Exam Dumps and Practice Test Dumps

Question: 221. Which BGP attribute is primarily used to identify the next-hop router for reaching a destination network?

1. Origin
   2. MED
   3. NEXT_HOP
   4. Local Preference

Correct Answer: 3. NEXT_HOP

Explanation:

The BGP NEXT_HOP attribute identifies the IP address of the router that should be used as the next hop toward the advertised destination. It is an important part of BGP route installation because the receiving router must have a reachable next hop before it can use the route for forwarding. Local Preference influences outbound path selection within an autonomous system, MED can influence the preferred entry point from a neighboring AS, and Origin describes how a route was introduced into BGP. Troubleshooting an unusable BGP route often includes verifying that its NEXT_HOP address is reachable.

Question: 222. Which Junos command displays the BGP routing table summary, including the number of established peers?

1. show bgp summary
   2. show route summary
   3. show ospf neighbor
   4. show interfaces terse

Correct Answer: 1. show bgp summary

Explanation:

The show bgp summary command provides a concise overview of BGP operation, including configured peers, peer states, AS information, and received or accepted route counts. It is commonly used as a first troubleshooting command when checking BGP sessions. The show ospf neighbor command is specific to OSPF, while show interfaces terse summarizes interface status. A general route summary provides routing-table information rather than the detailed BGP peer summary needed to verify whether BGP sessions are established.

Question: 223. Which OSPF network type normally elects a DR and BDR?

1. Point-to-point
   2. Broadcast
   3. Loopback
   4. Virtual link

Correct Answer: 2. Broadcast

Explanation:

OSPF normally elects a Designated Router (DR) and Backup Designated Router (BDR) on broadcast multiaccess networks such as Ethernet. The election helps reduce the number of full OSPF adjacencies and organizes LSA flooding across the shared segment. Point-to-point networks do not require DR or BDR elections because only two routers participate in the adjacency. Loopback interfaces represent logical interfaces rather than shared multiaccess OSPF segments. Virtual links provide logical connectivity between OSPF areas and are not themselves a normal broadcast network type requiring DR election.

Question: 224. What is the primary function of LACP when configuring an aggregated Ethernet interface?

1. Encrypt traffic between routers
   2. Exchange routing information between OSPF areas
   3. Assign addresses to IPv6 hosts
   4. Negotiate and maintain link aggregation between compatible devices

Correct Answer: 4. Negotiate and maintain link aggregation between compatible devices

Explanation:

The Link Aggregation Control Protocol (LACP) dynamically negotiates and maintains a logical aggregated link composed of multiple physical Ethernet interfaces. Aggregation can increase available bandwidth and provide redundancy because traffic can use multiple physical links. LACP also helps ensure that participating interfaces are correctly associated with the aggregated interface. It does not perform IP encryption, OSPF inter-area routing, or IPv6 address assignment. On Junos devices, LACP is commonly used with aggregated Ethernet interfaces when multiple physical connections need to operate as a single logical link.

Question: 225. Which route is selected by longest-prefix matching when forwarding an IPv4 packet?

1. The route with the most specific matching prefix
   2. The route with the highest metric regardless of prefix length
   3. The route learned first
   4. The route with the shortest next-hop address

Correct Answer: 1. The route with the most specific matching prefix

Explanation:

Longest-prefix matching selects the routing-table entry that matches the greatest number of leading destination-address bits. For example, if both 10.10.0.0/16 and 10.10.20.0/24 match a destination address, the /24 route is more specific and is selected for forwarding. This process occurs before other route-selection considerations used to determine which routes are installed in the routing table. It is fundamental to IP forwarding because networks can contain both broad summary routes and more specific routes for individual subnets.

Question: 226. Which Junos routing instance type can be used to create an independent virtual routing table on the same device?

1. Virtual Router
   2. Firewall filter
   3. Forwarding class
   4. CoS scheduler

Correct Answer: 1. Virtual Router

Explanation:

A Junos Virtual Router routing instance provides an independent routing environment on the same physical device. Each routing instance can maintain its own routing table and participate in routing protocols or static routing according to its configuration. This capability is useful when traffic from different networks needs to remain logically separated while sharing the same hardware. Firewall filters and forwarding classes serve different purposes related to packet filtering and traffic handling. A CoS scheduler controls traffic scheduling rather than creating an independent routing table.

Question: 227. Which OSPF packet is used to exchange summaries of the link-state database between neighbors?

1. Hello
   2. Link-State Request
   3. Database Description
   4. Link-State Acknowledgment

Correct Answer: 3. Database Description

Explanation:

OSPF Database Description (DBD) packets are used during adjacency formation to exchange summaries of the link-state databases between neighboring routers. The summaries allow routers to determine which LSAs they already possess and which ones they need to request. Hello packets establish and maintain neighbor relationships, while Link-State Requests ask for specific LSAs. Link-State Acknowledgments confirm receipt of LSAs. Database Description packets therefore play a key role during the database synchronization process before an OSPF adjacency reaches the Full state.

Question: 228. Which BGP community attribute prevents a route from being advertised to any BGP peer?

1. no-export
   2. internet
   3. no-advertise
   4. local-AS

Correct Answer: 3. no-advertise

Explanation:

The BGP no-advertise community tells a BGP speaker not to advertise the associated route to any BGP peer. This makes it more restrictive than no-export, which generally prevents advertisement outside the local autonomous system while still allowing appropriate internal propagation. The internet community indicates normal advertisement behavior, while local-AS has a different purpose associated with AS handling. Communities provide a flexible mechanism for applying routing policies to groups of routes without modifying each individual route attribute manually.

Question: 229. Which IPv4 address range is reserved for private networks?

1. 8.0.0.0/8
   2. 172.16.0.0/12
   3. 100.64.0.0/10
   4. 224.0.0.0/4

Correct Answer: 2. 172.16.0.0/12

Explanation:

The IPv4 range 172.16.0.0/12 is one of the three RFC 1918 private address ranges. It covers addresses from 172.16.0.0 through 172.31.255.255 and is commonly used for internal networks that are not directly routable across the public Internet. The other RFC 1918 ranges are 10.0.0.0/8 and 192.168.0.0/16. The 224.0.0.0/4 range is used for IPv4 multicast, while 100.64.0.0/10 is designated for carrier-grade NAT address sharing rather than RFC 1918 private addressing.

Question: 230. Which OSPF LSA type describes the router’s links and interfaces within an area?

1. Type 5 AS External LSA
   2. Type 3 Summary LSA
   3. Type 2 Network LSA
   4. Type 1 Router LSA

Correct Answer: 4. Type 1 Router LSA

Explanation:

A Type 1 Router LSA is originated by each OSPF router to describe its links, interfaces, and associated states within an area. The information is used by OSPF’s shortest-path calculation to construct the area’s topology. A Type 2 Network LSA is originated by the DR for an applicable multiaccess network, while Type 3 Summary LSAs are generated by ABRs to advertise inter-area networks. Type 5 LSAs describe external routes redistributed into OSPF. Router LSAs are therefore fundamental to calculating intra-area OSPF paths.

Question: 231. Which protocol is a link-state routing protocol that uses Level 1 and Level 2 routing domains?

1. RIP
   2. BGP
   3. IS-IS
   4. VRRP

Correct Answer: 3. IS-IS

Explanation:

IS-IS is a link-state interior gateway protocol that organizes routing using Level 1 and Level 2 areas. Level 1 routers primarily maintain routing information within an area, while Level 2 routers provide connectivity between areas and can form the backbone of the IS-IS domain. RIP is a distance-vector protocol, BGP is an exterior gateway protocol, and VRRP provides first-hop redundancy rather than dynamic routing. Understanding IS-IS levels is important when analyzing how routes are propagated between different parts of an IS-IS network.

Question: 232. Which Junos command is most useful for verifying the hardware components installed in a router?

1. show chassis hardware
   2. show route
   3. show system alarms
   4. show configuration

Correct Answer: 1. show chassis hardware

Explanation:

The show chassis hardware command displays information about hardware components installed in the Junos device, such as chassis components, line cards, modules, and other hardware inventory details depending on the platform. It is useful when verifying installed hardware or identifying the hardware associated with a particular interface. show route displays routing information, show system alarms reports active system alarms, and show configuration displays configuration data. Hardware inventory verification is therefore best performed with the chassis hardware command.

Question: 233. What is the main purpose of an OSPF Hello packet?

1. To carry external routes
   2. To establish and maintain OSPF neighbor relationships
   3. To acknowledge every received LSA
   4. To replace the routing table

Correct Answer: 2. To establish and maintain OSPF neighbor relationships

Explanation:

OSPF Hello packets are used to discover neighboring OSPF routers and maintain established neighbor relationships. They communicate important parameters such as the OSPF area, timers, network information, and router identity. Compatible routers can use these packets to establish neighbor relationships and eventually form adjacencies. Link-State Updates carry LSAs, while Link-State Acknowledgments confirm receipt of LSAs. Hello packets therefore provide the foundation for OSPF neighbor discovery and ongoing adjacency maintenance.

Question: 234. Which BGP path attribute is generally preferred when comparing two otherwise eligible routes within an autonomous system?

1. Lower Local Preference
   2. Higher Local Preference
   3. Higher MED
   4. Longer AS_PATH

Correct Answer: 2. Higher Local Preference

Explanation:

BGP generally prefers a higher Local Preference value when comparing otherwise eligible paths within an autonomous system. This attribute is designed to influence outbound traffic decisions and is propagated through iBGP. Network administrators can therefore assign higher Local Preference to routes associated with a preferred exit point. MED generally favors lower values, while a shorter AS_PATH is generally preferred over a longer one when that criterion is reached in the selection process. Understanding the direction of each attribute is important when predicting BGP path-selection behavior.

Question: 235. Which IPv6 mechanism detects whether an address is already in use before an interface begins using it?

1. BGP
   2. LACP
   3. Duplicate Address Detection
   4. VRRP

Correct Answer: 3. Duplicate Address Detection

Explanation:

IPv6 Duplicate Address Detection (DAD) determines whether another node is already using an IPv6 address before an interface begins using that address. DAD is part of IPv6 Neighbor Discovery and uses Neighbor Solicitation and Neighbor Advertisement messages to check address uniqueness on the local link. This helps prevent address conflicts. BGP provides interdomain routing, LACP manages link aggregation, and VRRP provides first-hop gateway redundancy. DAD is therefore specifically associated with verifying IPv6 address uniqueness.

Question: 236. Which Junos command displays the active system alarms?

1. show system alarms
   2. show chassis hardware
   3. show route
   4. show bgp summary

Correct Answer: 1. show system alarms

Explanation:

The show system alarms command displays active alarms reported by the Junos device. These alarms can help administrators identify hardware, environmental, or system conditions requiring attention. The exact alarm information depends on the platform and current system state. show chassis hardware provides hardware inventory rather than active alarm status, while show route displays routing information and show bgp summary provides BGP session information. Checking system alarms is a useful troubleshooting step when investigating unexpected device behavior.

Question: 237. Which routing protocol is primarily designed to exchange routing information between autonomous systems?

1. OSPF
   2. IS-IS
   3. RIP
   4. BGP

Correct Answer: 4. BGP

Explanation:

Border Gateway Protocol (BGP) is the principal routing protocol used to exchange routing information between autonomous systems. It is classified as an exterior gateway protocol and is fundamental to Internet-scale interdomain routing. OSPF, IS-IS, and RIP are primarily interior gateway protocols designed for routing within an autonomous system. BGP uses attributes such as AS_PATH, Local Preference, MED, NEXT_HOP, and Origin to implement policy-based route selection. Its ability to support routing policies is a major reason for its widespread use between autonomous systems.

Question: 238. Which OSPF neighbor state occurs after the routers have successfully exchanged Hello information and confirmed two-way communication?

1. Down
   2. Init
   3. 2-Way
   4. Loading

Correct Answer: 3. 2-Way

Explanation:

The OSPF 2-Way state indicates that two routers have successfully received Hello packets from each other and confirmed bidirectional communication. On certain network types, such as broadcast networks, not every 2-Way relationship proceeds to a Full adjacency because the DR and BDR determine which routers need full database synchronization. The Init state occurs when a router has received a Hello but has not yet confirmed two-way communication. Loading occurs later in the adjacency process as missing LSAs are requested and received.

Question: 239. What does GRES provide on a Junos device?

1. Faster DNS resolution
   2. Redundant Layer 2 switching
   3. Continuity of packet forwarding during a Routing Engine switchover
   4. Automatic IPv6 address assignment

Correct Answer: 3. Continuity of packet forwarding during a Routing Engine switchover

Explanation:

Graceful Routing Engine Switchover (GRES) is designed to help maintain forwarding continuity when control-plane responsibility moves from one Routing Engine to another. During a Routing Engine switchover, the forwarding plane can continue forwarding traffic while the backup Routing Engine assumes control. GRES is therefore focused on high availability during Routing Engine transitions. It does not provide DNS services, Layer 2 switching redundancy as its primary function, or IPv6 address assignment. GRES is commonly considered alongside other Junos high-availability mechanisms.

Question: 240. Which IPv4 address represents the default route?

1. 127.0.0.0/8
   2. 255.255.255.255/32
   3. 224.0.0.0/4
   4. 0.0.0.0/0

Correct Answer: 4. 0.0.0.0/0

Explanation:

The IPv4 default route is represented by 0.0.0.0/0. Because it contains zero network-specific prefix bits, it can match any IPv4 destination that does not have a more specific route in the routing table. Routers commonly use the default route as a path toward destinations for which no more specific routing information exists. The 127.0.0.0/8 range is reserved for loopback addressing, 224.0.0.0/4 is used for multicast, and 255.255.255.255/32 is the limited broadcast address. The default route therefore acts as the least-specific IPv4 route.