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

Question: 141. Which Junos command displays the forwarding table used to determine how packets are forwarded?

1. show route forwarding-table
   2. show configuration
   3. show bgp summary
   4. show system uptime

Correct Answer: 1. show route forwarding-table

Explanation:

The show route forwarding-table command displays information from the forwarding table used by the device to make packet-forwarding decisions. It can show destination prefixes, next hops, interfaces, and other forwarding information. This differs from the routing table, which contains routes learned or configured by routing protocols and static configuration. The forwarding table represents the information actually used by the forwarding plane. This command is particularly useful when troubleshooting situations where the routing table appears correct but traffic is not being forwarded as expected.

Question: 142. Which BGP attribute provides information about the preferred entry point into an autonomous system?

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

Correct Answer: 2. MED

Explanation:

The Multi-Exit Discriminator, or MED, is a BGP attribute that can be used to communicate a preference for how traffic should enter an autonomous system when multiple links exist between autonomous systems. A lower MED is generally preferred when comparing otherwise eligible paths from the same neighboring autonomous system. MED is different from Local Preference, which is primarily used inside an autonomous system to influence outbound path selection. MED should therefore be understood as an attribute that can influence inbound traffic selection.

Question: 143. Which OSPF area is normally used as the backbone for inter-area routing?

1. Area 1
   2. Area 100
   3. Area 0
   4. Area 255

Correct Answer: 3. Area 0

Explanation:

OSPF Area 0, also called the backbone area, is the central area used for inter-area routing in a hierarchical OSPF design. Other OSPF areas normally connect to Area 0 through Area Border Routers. The backbone allows routing information to be exchanged between different OSPF areas while helping the network scale more efficiently. Although other area numbers can be configured, Area 0 has a special role in OSPF’s hierarchical architecture.

Question: 144. Which IPv6 address is the loopback address?

1. FE80::1
   2. FF02::1
   3. FC00::1
   4. ::1

Correct Answer: 4. ::1

Explanation:

The IPv6 loopback address is ::1. It is equivalent in purpose to the IPv4 loopback address 127.0.0.1 and is used by a host to send traffic to itself. Loopback traffic does not require a physical network interface or an external router. FE80::/10 is the IPv6 link-local range, FF00::/8 is used for multicast, and FC00::/7 is associated with unique local addresses. Recognizing special IPv6 addresses is important for troubleshooting and configuration.

Question: 145. Which Junos command is useful for viewing the MAC addresses learned by a switch?

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

Correct Answer: 2. show ethernet-switching table

Explanation:

The show ethernet-switching table command displays learned Layer 2 MAC-address information. The output can help identify which interfaces or switching contexts have learned particular MAC addresses. This is useful when diagnosing Layer 2 connectivity, VLAN problems, unexpected MAC movement, or forwarding behavior. The routing table commands focus on Layer 3 information, while OSPF commands display routing-protocol state. MAC learning is a fundamental switching function and is separate from IP route calculation.

Question: 146. What happens when an OSPF router receives a valid Link-State Update containing new LSAs?

1. It ignores the information until BGP advertises the same routes
   2. It can update its link-state database and recalculate routes when necessary
   3. It converts the LSAs into DHCP messages
   4. It automatically creates a new autonomous system

Correct Answer: 2. It can update its link-state database and recalculate routes when necessary

Explanation:

OSPF Link-State Update packets carry LSAs that describe topology or routing information. When a router receives valid new or changed LSAs, it can update its link-state database and, when the topology change affects routing, perform an SPF calculation to determine new paths. The updated information can also be flooded to other appropriate OSPF neighbors. OSPF operates independently of BGP, DHCP, and autonomous-system creation, so those functions are not required for normal OSPF LSA processing.

Question: 147. Which Junos routing-table instance is normally used for IPv4 unicast routes?

1. inet6.0
   2. mpls.0
   3. inet.0
   4. iso.0

Correct Answer: 3. inet.0

Explanation:

The Junos inet.0 routing table is the primary routing table for IPv4 unicast routes in the default routing instance. IPv6 unicast routes are normally stored in inet6.0. Other routing tables are associated with different protocol families or forwarding functions. Knowing the correct routing-table name is useful when examining routes and troubleshooting protocol behavior in Junos. For example, an administrator can use commands such as show route table inet.0 to inspect IPv4 unicast routing information.

Question: 148. What is the main purpose of VRRP on a network?

1. To provide first-hop gateway redundancy
   2. To exchange external BGP routes
   3. To calculate OSPF shortest paths
   4. To aggregate Ethernet links

Correct Answer: 1. To provide first-hop gateway redundancy

Explanation:

Virtual Router Redundancy Protocol, or VRRP, provides gateway redundancy by allowing multiple routers to participate in a virtual router configuration. Hosts can use a virtual IP address as their default gateway while one router performs the active forwarding role and another can take over if necessary. This improves gateway availability without requiring hosts to change their configured default gateway. VRRP does not perform route aggregation, BGP exchange, or OSPF path calculation.

Question: 149. Which OSPF packet is used to acknowledge the receipt of LSAs?

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

Correct Answer: 3. Link-State Acknowledgment

Explanation:

The OSPF Link-State Acknowledgment packet is used to acknowledge receipt of LSAs. Reliable flooding is important because routers need consistent link-state information throughout an OSPF area. Acknowledgments allow routers to confirm that LSAs have been received, helping the protocol maintain reliable synchronization of its link-state database. Hello packets discover and maintain neighbors, Database Description packets summarize database contents, and Link-State Request packets ask neighbors for specific LSAs.

Question: 150. Which BGP relationship is established between routers located in different autonomous systems?

1. iBGP
   2. OSPF
   3. IS-IS
   4. eBGP

Correct Answer: 4. eBGP

Explanation:

External BGP, or eBGP, is used to exchange routing information between routers belonging to different autonomous systems. It is commonly used between an organization and an upstream provider or between separate autonomous systems operated by different organizations. Internal BGP, or iBGP, is used between BGP speakers within the same autonomous system. OSPF and IS-IS are interior gateway protocols and are not classifications of BGP sessions.

Question: 151. Which Junos command displays detailed information about installed routes for a particular destination prefix?

1. show route <prefix> detail
   2. show system uptime
   3. show interfaces terse
   4. show chassis hardware

Correct Answer: 1. show route <prefix> detail

Explanation:

The show route <prefix> detail command provides detailed information about a particular route in the Junos routing table. Depending on the route, the output can include protocol information, route preference, next-hop details, interface information, and other attributes. This is especially useful when investigating why a route was selected, why another route was rejected, or how traffic toward a specific destination will be forwarded. The other commands provide system, interface, or hardware information.

Question: 152. Which OSPF feature helps reduce the number of adjacencies on a broadcast Ethernet segment?

1. Route reflector
   2. Designated Router
   3. Autonomous System Boundary Router
   4. Default route

Correct Answer: 2. Designated Router

Explanation:

OSPF elects a Designated Router on broadcast multi-access networks to reduce the number of full adjacencies that would otherwise be required. Instead of every router establishing a full adjacency with every other router on the segment, routers establish the appropriate relationships involving the DR and Backup Designated Router. The DR also plays an important role in representing the multi-access network through a Type 2 Network LSA. This design reduces unnecessary adjacency and LSA-flooding overhead.

Question: 153. Which address range is used for IPv6 unique local unicast addresses?

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

Correct Answer: 3. FC00::/7

Explanation:

The IPv6 FC00::/7 prefix is reserved for Unique Local Addresses, commonly abbreviated as ULA. These addresses are intended for private internal communication and are not generally routed across the public Internet. They are conceptually similar to private IPv4 addressing, although the addressing architecture is different. FE80::/10 is the link-local range, FF00::/8 is the multicast range, and 2000::/3 contains a major portion of globally routable unicast space.

Question: 154. Which BGP attribute is commonly used to influence the preferred outbound path inside an autonomous system?

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

Correct Answer: 3. Local Preference

Explanation:

BGP Local Preference is used to influence outbound route selection within an autonomous system. When multiple eligible BGP routes are available, a higher Local Preference is generally preferred. This attribute is particularly useful when an organization has multiple external connections and wants to control which connection is used for outbound traffic. Unlike MED, which can influence how traffic enters an autonomous system, Local Preference is primarily an internal BGP mechanism for selecting the preferred exit path.

Question: 155. What is the purpose of the OSPF dead interval?

1. It specifies how long a router can go without receiving expected Hello packets before declaring a neighbor down
   2. It determines the maximum number of OSPF areas
   3. It defines the maximum BGP AS_PATH length
   4. It controls the Ethernet MTU size

Correct Answer: 1. It specifies how long a router can go without receiving expected Hello packets before declaring a neighbor down

Explanation:

The OSPF dead interval determines how long an OSPF router waits without receiving valid Hello packets from a neighbor before declaring that neighbor unavailable. The timer works together with the Hello interval, and compatible timer values are normally required for an adjacency to form correctly. If the dead interval expires, OSPF can remove the neighbor relationship and recalculate routes as necessary. Incorrect timer configuration is therefore a common cause of OSPF adjacency problems.

Question: 156. Which Junos feature allows a router to maintain separate routing tables for different logical routing environments?

1. Firewall filter
   2. Routing instance
   3. LACP
   4. BFD

Correct Answer: 2. Routing instance

Explanation:

A Junos routing instance provides a separate logical routing environment within the device. Different routing instances can maintain independent routing information and can be used to support technologies such as virtual routing and forwarding. This allows one physical device to participate in multiple logically separated routing domains. Routing instances are useful in service-provider networks, multi-tenant environments, and other designs where traffic and routing information must remain logically separated.

Question: 157. Which BGP community indicates that a route should not be advertised to any BGP peer?

1. no-export
   2. no-advertise
   3. internet
   4. standard

Correct Answer: 2. no-advertise

Explanation:

The BGP no-advertise community is used to prevent a route from being advertised to BGP peers. It provides a stronger propagation restriction than no-export, which specifically limits advertisement outside the local autonomous system. Communities can be attached to routes and then acted upon through routing policies. This allows administrators to control how routes are propagated without having to create a separate prefix-specific rule for every possible destination.

Question: 158. Which command can be used to verify the hardware inventory of a Junos device?

1. show chassis hardware
   2. show route
   3. show ospf neighbor
   4. show bgp summary

Correct Answer: 1. show chassis hardware

Explanation:

The show chassis hardware command displays hardware inventory information for a Junos device. It can provide details about installed components such as the chassis, Routing Engines, line cards, and other hardware modules depending on the platform. This command is useful when verifying hardware installation or troubleshooting hardware-related issues. The other commands focus on routing or protocol information rather than physical hardware inventory.

Question: 159. What is the primary purpose of a Junos firewall filter?

1. To calculate OSPF routes
   2. To establish BGP sessions
   3. To control or classify packets based on defined matching conditions
   4. To negotiate aggregated Ethernet links

Correct Answer: 3. To control or classify packets based on defined matching conditions

Explanation:

Junos firewall filters provide packet-processing rules that can match traffic based on characteristics such as source or destination addresses, protocols, ports, and other supported fields. Actions can include accepting, discarding, counting, logging, or otherwise processing matching traffic. Firewall filters can therefore be used for traffic control, security enforcement, classification, and operational monitoring. They do not calculate routing paths, establish BGP sessions, or perform link aggregation.

Question: 160. Which BGP attribute records the origin of a route within the BGP path-selection process?

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

Correct Answer: 1. Origin

Explanation:

The BGP Origin attribute indicates how a route entered BGP and is considered during BGP path selection. Common origin values include IGP, EGP, and Incomplete, with IGP generally preferred over EGP and Incomplete when this attribute is compared. The Origin attribute is distinct from AS_PATH, which records autonomous systems traversed, and Local Preference, which influences outbound path selection within an autonomous system. Understanding individual BGP attributes helps explain why one eligible route may be selected over another.