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

Question: 261. Which Junos command displays routes learned specifically through BGP?

1. show route protocol bgp
   2. show route forwarding-table
   3. show bgp summary
   4. show ospf neighbor

Correct Answer: 1. show route protocol bgp

Explanation:

The show route protocol bgp command filters the Junos routing table to display routes whose protocol source is BGP. This is useful when verifying whether BGP-learned prefixes have been installed in the routing table. show bgp summary provides information about BGP sessions and peer statistics, but it does not provide the same route-focused view. show route forwarding-table examines the forwarding table, while show ospf neighbor is used for OSPF adjacency information. Filtering routes by protocol is an effective way to troubleshoot route learning and installation.

Question: 262. What is the primary purpose of OSPF SPF calculation?

1. To negotiate Ethernet aggregation
   2. To calculate the shortest paths through the OSPF topology
   3. To assign IPv6 addresses
   4. To establish BGP TCP sessions

Correct Answer: 2. To calculate the shortest paths through the OSPF topology

Explanation:

OSPF uses the Shortest Path First (SPF) algorithm to calculate the shortest paths through the topology represented in its link-state database. Each router builds a view of the network topology from received LSAs and then calculates the best paths to reachable destinations. The resulting routes can be installed in the routing table. Ethernet aggregation is handled by mechanisms such as LACP, IPv6 address assignment can use mechanisms such as SLAAC, and BGP establishes its own TCP sessions. SPF is therefore central to OSPF route calculation.

Question: 263. Which BGP attribute is normally preferred when it has a higher value?

1. MED
   2. AS_PATH length
   3. Local Preference
   4. Origin type

Correct Answer: 3. Local Preference

Explanation:

BGP generally prefers a higher Local Preference value when selecting among otherwise eligible paths within an autonomous system. Administrators can use Local Preference to influence which exit point is preferred for outbound traffic. MED generally favors a lower value, while a shorter AS_PATH is generally preferred over a longer path. Origin is also considered during BGP path selection but is not normally interpreted as a simple higher-is-better numeric attribute. Local Preference is therefore a key tool for controlling outbound traffic decisions across an autonomous system.

Question: 264. Which IPv4 address is the limited broadcast address?

1. 0.0.0.0
   2. 127.0.0.1
   3. 224.0.0.1
   4. 255.255.255.255

Correct Answer: 4. 255.255.255.255

Explanation:

The IPv4 address 255.255.255.255 represents the limited broadcast address. Packets sent to this address are intended for all IPv4 hosts on the local broadcast domain and are not routed by routers to other networks. The address 0.0.0.0 has several special uses, including representing an unspecified address and the destination in a default route when used with a /0 prefix. 127.0.0.1 is the IPv4 loopback address, while 224.0.0.1 is an IPv4 multicast address representing all hosts on the local subnet.

Question: 265. Which Junos command is useful for displaying the status of all configured interfaces in a compact format?

1. show system alarms
   2. show interfaces terse
   3. show route
   4. show configuration

Correct Answer: 2. show interfaces terse

Explanation:

The show interfaces terse command provides a concise summary of configured interfaces and their administrative and operational states. It is commonly used as an initial troubleshooting command because it quickly shows whether interfaces are up or down and can also display address information. The full show interfaces command provides much more detailed operational information. show system alarms reports alarms, show route displays routing information, and show configuration displays configuration hierarchy. The terse interface view is therefore useful for quickly assessing overall interface status.

Question: 266. Which BGP mechanism allows multiple equal-cost paths to be installed for forwarding?

1. Route reflection
   2. Communities
   3. BGP multipath
   4. MED

Correct Answer: 3. BGP multipath

Explanation:

BGP multipath allows multiple eligible BGP paths to be installed in the forwarding table when they meet the configured requirements for multipath selection. This can provide load sharing across multiple paths and improve redundancy. Route reflection is designed to reduce the need for a full iBGP mesh, while communities provide policy information that can be used to control route handling. MED can influence path selection between autonomous systems but does not itself enable multipath forwarding. BGP multipath therefore addresses the use of multiple qualifying paths for forwarding.

Question: 267. Which OSPF packet type is responsible for acknowledging received LSAs?

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

Correct Answer: 1. Link-State Acknowledgment

Explanation:

OSPF Link-State Acknowledgment (LSAck) packets are used to acknowledge receipt of link-state advertisements. Reliable LSA flooding is important because routers need synchronized link-state databases to calculate consistent paths. Database Description packets exchange summaries of database contents, Link-State Requests ask for specific LSAs, and Hello packets establish and maintain neighbor relationships. The acknowledgment mechanism allows OSPF routers to confirm that LSAs have been received, supporting reliable distribution of topology information throughout the appropriate OSPF area.

Question: 268. Which Junos routing table is normally used for IPv4 unicast routes?

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

Correct Answer: 3. inet.0

Explanation:

The Junos inet.0 routing table is the primary routing table for IPv4 unicast routes. It contains IPv4 routes learned through protocols such as OSPF, BGP, RIP, or static configuration, depending on the device configuration. The inet6.0 table is used for IPv6 unicast routes. Other protocol families and forwarding functions use different routing tables. Knowing the appropriate routing table is important when troubleshooting route installation because a route may exist in a different protocol-family table than the one being examined.

Question: 269. Which protocol is primarily used to provide first-hop gateway redundancy?

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

Correct Answer: 2. VRRP

Explanation:

Virtual Router Redundancy Protocol (VRRP) provides first-hop gateway redundancy by allowing multiple routers to share a virtual gateway address. Hosts can use the virtual address as their default gateway, while participating routers provide redundancy if the active router becomes unavailable. OSPF, BGP, and IS-IS are routing protocols rather than first-hop redundancy protocols. VRRP therefore addresses gateway availability at the local network edge and helps prevent a single router failure from isolating hosts from upstream networks.

Question: 270. Which OSPF device connects different OSPF areas and exchanges inter-area routing information?

1. Area Border Router
   2. Designated Router
   3. Route Reflector
   4. Autonomous System Boundary Router

Correct Answer: 1. Area Border Router

Explanation:

An Area Border Router (ABR) connects one OSPF area to another and exchanges routing information between those areas. An ABR maintains link-state information for the areas to which it is connected and can generate Type 3 Summary LSAs to advertise networks between areas. A Designated Router operates on applicable multiaccess networks, while a Route Reflector is a BGP scalability mechanism. An Autonomous System Boundary Router (ASBR) connects OSPF to external routing information, such as routes redistributed from another routing protocol. These roles can sometimes exist on the same physical router but represent different functions.

Question: 271. Which IPv6 address type is automatically associated with an IPv6-enabled interface for communication on the local link?

1. Global unicast
   2. Unique local
   3. Link-local
   4. Multicast-only

Correct Answer: 3. Link-local

Explanation:

IPv6 link-local addresses are associated with IPv6-enabled interfaces and are used for communication on the local link. They are normally drawn from the FE80::/10 prefix and are not intended to be routed across IPv6 routers. Link-local addressing is essential for Neighbor Discovery and is also commonly used by IPv6 routing protocols for neighbor communication. Global unicast addresses provide broader routability, while unique local addresses are intended for internal addressing. Multicast addresses identify groups of receivers rather than representing a normal unicast interface address.

Question: 272. Which command can be used to compare pending Junos configuration changes with the active configuration?

1. show route
   2. show | compare
   3. show interfaces terse
   4. show chassis hardware

Correct Answer: 2. show | compare

Explanation:

The show | compare command allows an administrator to review differences between the candidate configuration and the currently active configuration. This is useful before committing changes because it helps verify that only the intended configuration statements will be activated. show route examines routing information, show interfaces terse summarizes interface status, and show chassis hardware provides hardware inventory. Reviewing candidate changes before a commit is an important operational practice because it reduces the likelihood of activating unintended configuration modifications.

Question: 273. Which BGP attribute is used to identify the autonomous systems traversed by a route advertisement?

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

Correct Answer: 3. AS_PATH

Explanation:

The AS_PATH attribute records the sequence of autonomous systems through which a BGP route advertisement has passed. It is included in BGP updates and provides both path-selection information and an important loop-prevention mechanism. A router can reject an advertisement if its own AS number appears in the path. NEXT_HOP identifies the next-hop address, Local Preference influences outbound path selection within an AS, and MED can influence the preferred entry point from a neighboring AS. AS_PATH is therefore a fundamental BGP path attribute.

Question: 274. Which Junos command displays active alarms reported by the system?

1. show route protocol bgp
   2. show system alarms
   3. show bgp summary
   4. show route forwarding-table

Correct Answer: 2. show system alarms

Explanation:

The show system alarms command displays active alarms generated by the Junos device. Depending on the platform and circumstances, alarms can identify hardware, environmental, or system-related conditions that require investigation. The other commands focus on BGP routes, BGP peer information, or the forwarding table. Checking system alarms is a useful troubleshooting step when a device reports an unexpected condition or when administrators need to determine whether a hardware or environmental problem is currently active.

Question: 275. Which OSPF timer determines how long a router waits before declaring a neighbor down after not receiving Hello packets?

1. Dead interval
   2. SPF interval
   3. LSA refresh interval
   4. Retransmission interval

Correct Answer: 1. Dead interval

Explanation:

The OSPF dead interval specifies how long a router can go without receiving an expected Hello packet before declaring the neighbor down. The Hello interval controls how frequently Hello packets are sent, while the dead interval provides the timeout used to detect loss of neighbor communication. OSPF neighbors on the same network generally need compatible timer values to establish and maintain adjacency. SPF and LSA-related timers serve different purposes and do not directly define the neighbor-down detection period.

Question: 276. Which Junos configuration statement is commonly used to define a static IPv4 route?

1. protocols ospf area
   2. routing-options static route
   3. protocols bgp group
   4. interfaces ge-0/0/0 unit

Correct Answer: 2. routing-options static route

Explanation:

Junos static IPv4 routes are commonly configured under the routing-options static hierarchy using a statement such as route. Static routes provide manually defined paths to destinations and do not require a dynamic routing protocol to learn the route. OSPF and BGP configuration belongs under their respective protocol hierarchies, while interface configuration defines physical and logical interfaces. Static routes are useful for simple topologies, specific reachability requirements, or as carefully controlled backup paths.

Question: 277. Which BGP community normally indicates that a route should be advertised normally to BGP peers?

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

Correct Answer: 3. internet

Explanation:

The well-known BGP internet community indicates that the route can be advertised normally to BGP peers, subject to the routing policies configured by the network. In contrast, no-advertise prevents advertisement to BGP peers, while no-export generally restricts advertisement outside the local autonomous system. The blackhole community is not a standard well-known community with the same universal behavior and is often associated with provider-specific routing policies. BGP communities therefore allow administrators to communicate route-handling intentions between routing-policy components.

Question: 278. Which protocol uses Level 1 and Level 2 routers to provide hierarchical routing?

1. VRRP
   2. IS-IS
   3. LACP
   4. BFD

Correct Answer: 2. IS-IS

Explanation:

IS-IS uses a hierarchical Level 1 and Level 2 architecture. Level 1 routers primarily maintain information within an area, while Level 2 routers provide connectivity between areas and can form the backbone of an IS-IS routing domain. This hierarchy helps organize routing information in larger networks. VRRP is a first-hop redundancy protocol, LACP manages link aggregation, and BFD provides rapid failure detection. Recognizing the Level 1 and Level 2 terminology is therefore a strong indicator that the question is referring to IS-IS.

Question: 279. Which Junos command displays the current hardware inventory of the device?

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

Correct Answer: 2. show chassis hardware

Explanation:

The show chassis hardware command displays hardware inventory information for a Junos device. The output can identify installed chassis components and other hardware elements, depending on the platform. This command is useful when verifying hardware installation or investigating whether the expected components are recognized by the operating system. show system uptime reports system runtime information, show configuration displays configuration, and show route displays routing information. Hardware inventory and operational configuration should therefore be examined with different commands.

Question: 280. Which BGP attribute is generally preferred when its value represents a shorter path through autonomous systems?

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

Correct Answer: 4. AS_PATH

Explanation:

The BGP AS_PATH attribute contains the sequence of autonomous systems traversed by a route. When BGP reaches the AS_PATH comparison stage and other higher-priority criteria have not selected a route, a shorter AS_PATH is generally preferred. This can make a route appear more direct from the perspective of autonomous-system traversal. Local Preference is generally preferred when higher, while MED is generally preferred when lower. Origin has a different role in path selection. AS_PATH also provides important loop-prevention functionality by allowing routers to identify routes that have already traversed their own AS.