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

 

Question: 81. Which Junos command can be used to display the routing table for IPv6 unicast routes?

1. show route table inet6.0
   2. show route table inet.0
   3. show arp
   4. show ethernet-switching table

Correct Answer: 1. show route table inet6.0

Explanation:

The inet6.0 routing table is the primary Junos routing table for IPv6 unicast routes. The command show route table inet6.0 allows an administrator to examine routes installed in that table, including routes learned through connected interfaces, static configuration, OSPFv3, BGP, and other supported routing mechanisms. The inet.0 table is used for IPv4 unicast routes. The ARP table is associated with IPv4 neighbor resolution, while the Ethernet switching table contains Layer 2 MAC-learning information. Knowing which routing table contains a particular address family is useful when troubleshooting IPv4 and IPv6 forwarding.

Question: 82. Which OSPF packet type is primarily responsible for establishing and maintaining neighbor relationships?

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

Correct Answer: 3. Hello

Explanation:

OSPF Hello packets are used to discover neighboring routers and maintain OSPF neighbor relationships. They are sent periodically through participating interfaces and contain information that allows routers to verify compatible parameters and establish bidirectional communication. If expected Hello packets stop arriving for the configured dead interval, the neighbor can be declared down. Database Description packets are used during database synchronization, Link-State Requests ask for specific LSAs, and Link-State Updates carry LSAs. Therefore, when troubleshooting an OSPF adjacency that does not form, checking Hello exchange and matching interface parameters is an important first step.

Question: 83. Which BGP attribute is generally used to identify the preferred path for traffic leaving an autonomous system?

1. MED
   2. Local preference
   3. Origin
   4. Community

Correct Answer: 2. Local preference

Explanation:

Local preference is commonly used to influence outbound traffic within an autonomous system. When multiple eligible BGP routes exist toward the same destination, a higher local-preference value is generally preferred. Because local preference is distributed through iBGP, it can help an organization establish a consistent preferred exit point across multiple routers. MED is more commonly associated with influencing how a neighboring AS enters the local AS, while origin and community have different roles. Routing policies can be used to assign or modify local preference based on prefixes, peers, communities, or other routing characteristics.

Question: 84. What is the primary purpose of the BGP NEXT_HOP attribute?

1. Identify the OSPF area containing the destination
   2. Specify the IP address that should be used as the next forwarding hop toward the advertised destination
   3. Define the BGP autonomous system number
   4. Indicate the route’s MED value

Correct Answer: 2. Specify the IP address that should be used as the next forwarding hop toward the advertised destination

Explanation:

The BGP NEXT_HOP attribute identifies the IP address that a router should use as the next hop when forwarding traffic toward a BGP destination. A BGP route can be present in the routing table but still be unusable if the next hop cannot be resolved through the appropriate routing information. This makes next-hop reachability an important part of BGP troubleshooting. The AS path identifies autonomous systems traversed, MED is a path-selection attribute, and the OSPF area is unrelated to the NEXT_HOP attribute. Checking next-hop reachability can help explain why an apparently valid BGP route is not active.

Question: 85. Which Junos command is useful for displaying the current system uptime and basic system status?

1. show system uptime
   2. show route receive-protocol
   3. show ospf neighbor
   4. show interfaces extensive

Correct Answer: 1. show system uptime

Explanation:

The show system uptime command provides information about how long the Junos device has been running and can also display related system-time information. This is useful when investigating recent reboots, system restarts, or unexpected control-plane events. Interface and routing commands provide much more specialized information. For example, show interfaces extensive gives detailed interface statistics, while OSPF and routing-protocol commands provide information about network operation. System uptime can also help correlate device events with monitoring alerts or configuration changes. It is a simple but useful command during initial troubleshooting.

Question: 86. Which routing protocol uses a link-state database and the SPF algorithm to calculate paths?

1. RIP
   2. BGP
   3. OSPF
   4. DHCP

Correct Answer: 3. OSPF

Explanation:

OSPF is a link-state routing protocol that maintains a link-state database representing the topology of its routing area. It uses the Shortest Path First algorithm, based on Dijkstra’s algorithm, to calculate paths through that topology. Each router builds its own shortest-path tree and derives routing information from the resulting calculation. RIP uses a distance-vector approach, while BGP uses a path-vector model based on multiple route attributes. DHCP is not a routing protocol. Understanding OSPF’s link-state operation helps explain its neighbor relationships, LSAs, database synchronization, and route convergence behavior.

Question: 87. Which Junos command can be used to display detailed information about a BGP route, including its attributes and next hop?

1. show route protocol ospf
   2. show route detail
   3. show system users
   4. show interfaces terse

Correct Answer: 2. show route detail

Explanation:

The show route <prefix> detail command can provide detailed information about a particular route, including its protocol source, preference, next hop, and relevant route attributes. This is especially useful when troubleshooting BGP because administrators may need to determine why a route was selected, rejected, or marked inactive. A more general routing-table display may not provide enough detail for complex route-selection problems. Interface and system-user commands address different operational areas. When investigating a specific destination, examining the detailed route entry can reveal important information about next-hop resolution and route selection.

Question: 88. Which protocol is commonly used by Junos devices to exchange routing information within an autonomous system when a hierarchical link-state design is desired?

1. SMTP
   2. BGP
   3. IS-IS
   4. FTP

Correct Answer: 3. IS-IS

Explanation:

IS-IS is an interior gateway protocol that uses a link-state architecture and supports a hierarchical Level 1 and Level 2 design. It is commonly deployed within autonomous systems, particularly in large service-provider networks. Level 1 routing handles destinations within an area, while Level 2 provides connectivity between areas. BGP is primarily used for inter-AS routing, while SMTP and FTP are application-layer protocols unrelated to network routing. IS-IS also maintains a link-state database and uses SPF calculations, making it an important protocol to understand when studying large-scale Junos routing environments.

Question: 89. What is the main purpose of the OSPF designated router election on a broadcast network?

1. Assign IP addresses to hosts
   2. Encrypt OSPF messages
   3. Reduce the number of OSPF adjacencies and flooding relationships
   4. Select the default route for the network

Correct Answer: 3. Reduce the number of OSPF adjacencies and flooding relationships

Explanation:

OSPF elects a designated router on broadcast multiaccess networks to reduce the number of full adjacencies and simplify link-state flooding. Without a DR, every OSPF router on the segment would potentially need a full relationship with every other router, increasing protocol overhead as the number of routers grows. The DR and backup designated router provide a more scalable mechanism for exchanging topology information. The DR election does not assign IP addresses, encrypt OSPF traffic, or automatically determine the default route. Understanding DR and BDR behavior is particularly important when troubleshooting OSPF on Ethernet segments.

Question: 90. Which IPv4 prefix 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. It matches destinations for which the routing table contains no more-specific route. Because its prefix length is zero, it is less specific than every normal IPv4 route and therefore serves as a fallback path. It is commonly used on routers at network edges to forward unknown destinations toward an upstream router. 127.0.0.0/8 is reserved for loopback addressing, 224.0.0.0/4 is the IPv4 multicast range, and 255.255.255.255 is the limited broadcast address. Understanding prefix specificity is essential when analyzing default-route behavior.

Question: 91. Which Junos feature allows a router to keep forwarding traffic during certain Routing Engine control-plane transitions?

1. GRES
   2. LACP
   3. ARP
   4. Route reflection

Correct Answer: 1. GRES

Explanation:

Graceful Routing Engine Switchover, or GRES, is a Junos high-availability feature designed for systems with redundant Routing Engines. During a Routing Engine switchover, GRES helps maintain packet forwarding through the forwarding plane while control transitions between Routing Engines. GRES should be distinguished from other high-availability mechanisms that synchronize routing-protocol state or application state. LACP provides link aggregation, ARP resolves IPv4 addresses to MAC addresses, and route reflection improves iBGP scalability. Understanding how GRES interacts with other redundancy features is important when designing resilient Junos platforms.

Question: 92. Which BGP community is commonly used to indicate that a route should not be advertised outside the local autonomous system?

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

Correct Answer: 2. no-export

Explanation:

The well-known BGP no-export community is used to control route propagation so that a route is not advertised outside the local autonomous system or applicable confederation boundary. This makes it useful when a route should remain within a particular routing domain while still being distributed internally. The no-advertise community has a more restrictive meaning and prevents the route from being advertised to any BGP peer. The internet community indicates broad advertisement, subject to policy, while local-AS has specific behavior associated with local-AS and confederation scenarios. Communities are commonly applied through routing policy.

Question: 93. Which Junos command can be used to examine the OSPF link-state database?

1. show ospf database
   2. show bgp summary
   3. show arp
   4. show chassis hardware

Correct Answer: 1. show ospf database

Explanation:

The show ospf database command displays information from the OSPF link-state database. It can help administrators inspect LSAs and understand the topology information OSPF has learned within an area. This is especially useful when troubleshooting unexpected routes, missing topology information, or adjacency synchronization problems. show bgp summary provides BGP session information, show arp displays IPv4 neighbor mappings, and show chassis hardware provides hardware details. Examining the OSPF database can help determine whether a routing problem originates from missing LSAs, incorrect advertisements, or another stage of the route-calculation process.

Question: 94. Which IPv6 prefix is reserved for unique local addresses?

1. FE80::/10
   2. FF00::/8
   3. FC00::/7
   4. 2000::/3

Correct Answer: 3. FC00::/7

Explanation:

IPv6 unique local addresses use the FC00::/7 range. They are intended for private addressing within organizations and are not designed for global Internet routing. In practice, unique local addressing commonly uses the FD00::/8 portion with an appropriate locally assigned Global ID. FE80::/10 is reserved for link-local addresses, FF00::/8 is the multicast range, and 2000::/3 represents global unicast addressing. Understanding these address categories helps administrators distinguish local-only communication from globally routable IPv6 traffic and is useful when designing and troubleshooting IPv6 networks.

Question: 95. What is the primary function of the BGP AS_PATH attribute during route selection and loop prevention?

1. Identify the physical interface speed
   2. Record autonomous systems traversed by the route and help detect routing loops
   3. Assign a local preference value automatically
   4. Determine the Ethernet VLAN ID

Correct Answer: 2. Record autonomous systems traversed by the route and help detect routing loops

Explanation:

The BGP AS_PATH attribute records the autonomous systems through which a route advertisement has passed. This information is useful both for route selection and for loop prevention. A BGP router can reject a route if its own autonomous system number appears in the AS path, preventing the route from being accepted back into the same AS through a routing loop. AS path length can also influence which route is preferred. Local preference is a separate BGP attribute, while VLAN IDs and interface speeds are Layer 2 or physical characteristics unrelated to AS path processing.

Question: 96. Which Junos command is useful for displaying the MAC addresses learned by a switch?

1. show route
   2. show ospf neighbor
   3. show ethernet-switching table
   4. show system uptime

Correct Answer: 3. show ethernet-switching table

Explanation:

The show ethernet-switching table command displays MAC addresses learned by the switching system and provides information about their associated interfaces and VLAN contexts. This is useful when troubleshooting Layer 2 connectivity, unexpected MAC movement, flooding, or switching behavior. If a switch has not learned the expected MAC address, administrators can investigate interface status, VLAN membership, traffic flow, and other Layer 2 conditions. show route examines Layer 3 routing information, while OSPF and system-uptime commands address different operational areas. The Ethernet switching table is therefore a key Junos troubleshooting resource for Layer 2 networks.

Question: 97. Which mechanism allows BGP routes to carry additional policy information without changing the destination prefix?

1. BGP communities
   2. OSPF cost
   3. Ethernet MTU
   4. ARP cache

Correct Answer: 1. BGP communities

Explanation:

BGP communities are attributes that can be attached to routes to carry policy-related information between BGP speakers. Administrators can use communities to classify routes and then apply routing policies based on those classifications. For example, communities can be used to influence route advertisement, local preference, or other policy actions. Communities do not change the destination prefix itself. OSPF cost is an IGP metric, Ethernet MTU describes maximum frame or packet size, and the ARP cache maps IPv4 addresses to Layer 2 addresses. Communities therefore provide a flexible method for communicating routing-policy information.

Question: 98. Which OSPF LSA type represents routes redistributed into an OSPF autonomous system from an external source?

1. Type 2
   2. Type 5
   3. Type 1
   4. Type 3

Correct Answer: 2. Type 5

Explanation:

OSPF Type 5 LSAs are used to advertise external routes that have been redistributed into OSPF. These routes may originate from another routing protocol, static routing, or another external source. Type 5 LSAs are normally flooded throughout the OSPF autonomous system, except in area types that specifically restrict external LSAs. Type 1 LSAs describe routers, Type 2 LSAs represent multiaccess networks, and Type 3 LSAs are generated by ABRs to advertise inter-area networks. Understanding external LSAs is important when troubleshooting redistributed routes and determining why an external destination is or is not present in an OSPF routing table.

Question: 99. Which Junos command can be used to display information about the device’s installed hardware components?

1. show chassis hardware
   2. show route receive-protocol bgp
   3. show ospf database
   4. show ethernet-switching table

Correct Answer: 1. show chassis hardware

Explanation:

The show chassis hardware command displays information about hardware components installed in the Junos device. Depending on the platform, the output can include chassis components, Routing Engines, line cards, modules, and other hardware information. This command is useful when verifying hardware inventory or investigating hardware-related issues. Routing commands provide Layer 3 information, OSPF database commands display routing topology information, and Ethernet-switching commands show Layer 2 MAC-learning information. Hardware inventory is particularly useful during maintenance, replacement, and troubleshooting activities where the exact installed components need to be confirmed.

Question: 100. Which routing table entry is selected when multiple routes match a destination and one route has the longest prefix length?

1. The route with the lowest interface speed
   2. The route with the shortest AS path regardless of prefix length
   3. The route with the longest matching prefix
   4. The route learned most recently

Correct Answer: 3. The route with the longest matching prefix

Explanation:

The longest-prefix-match principle means that a routing lookup generally selects the route with the most specific prefix that matches the destination address. For example, a /24 route is more specific than a /16 route when both match the same destination. This principle is fundamental to IP forwarding and is considered before many other route-selection factors. A route’s age, interface speed, or BGP AS path does not override the basic requirement to select the most specific matching destination prefix. Understanding longest-prefix matching is essential when analyzing overlapping routes, static routes, and dynamically learned routes.