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

 

Question: 41. Which Junos operational command can be used to view the status of a BGP session and summarize information about BGP peers?

1. show ospf interface
   2. show bgp summary
   3. show route forwarding-table
   4. show ethernet-switching table

Correct Answer: 2. show bgp summary

Explanation:

The show bgp summary command provides a concise overview of BGP peers and their session status. It can display information such as the local autonomous system, configured neighbors, peer state, number of routes received, and other session-related details. This makes it particularly useful when determining whether BGP sessions are established and exchanging routing information. show ospf interface focuses on OSPF interfaces, while forwarding-table and Ethernet-switching commands provide information about forwarding and Layer 2 switching. When troubleshooting BGP, the summary command is often an effective starting point before examining detailed routes or policies.

Question: 42. Which BGP attribute is normally considered first among the listed attributes when selecting a preferred route on a Junos device?

1. Local preference
   2. MED
   3. Origin
   4. Router ID

Correct Answer: 1. Local preference

Explanation:

Local preference is an important BGP attribute used to influence outbound route selection within an autonomous system. In the Junos BGP route-selection process, a higher local-preference value is generally preferred when comparing otherwise eligible routes. It is commonly used to control which external exit point the autonomous system should use. MED, origin, and router ID are considered at different stages of route selection. Local preference is propagated through iBGP and is therefore particularly useful for establishing consistent outbound-routing policies across an organization. BGP policy can modify local preference to implement deliberate traffic-engineering decisions.

Question: 43. Which protocol provides a loop-prevention mechanism by recording the autonomous systems a BGP route has traversed?

1. OSPF
   2. LACP
   3. BGP
   4. VRRP

Correct Answer: 3. BGP

Explanation:

BGP uses the AS path attribute to record the sequence of autonomous systems through which a route advertisement has passed. This provides an important loop-prevention mechanism. When an autonomous system receives a route advertisement containing its own AS number in the AS path, the route can be rejected because accepting it could create an inter-AS routing loop. The AS path is also considered during BGP route selection. OSPF prevents loops through its link-state topology and SPF calculation, while LACP and VRRP serve link aggregation and gateway-redundancy functions respectively.

Question: 44. What does the Junos command show route forwarding-table primarily display?

1. BGP policy configuration
   2. OSPF neighbor states
   3. Candidate configuration changes
   4. Packet-forwarding information installed for forwarding traffic

Correct Answer: 4. Packet-forwarding information installed for forwarding traffic

Explanation:

The show route forwarding-table command provides information about the forwarding table used to make actual packet-forwarding decisions. The routing table contains routing information learned from connected interfaces, static routes, and routing protocols, while the forwarding table represents information programmed for packet forwarding. Examining the forwarding table can be especially useful when a route appears correctly installed in the routing table but traffic does not behave as expected. OSPF neighbor commands, BGP policy configuration, and candidate configuration information serve different troubleshooting purposes and do not directly display the forwarding table.

Question: 45. Which OSPF packet type is used to request specific link-state information from a neighboring router?

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

Correct Answer: 1. Link-State Request

Explanation:

An OSPF Link-State Request, or LSR, is used when a router needs specific link-state information from a neighbor. During database synchronization, routers compare the information they know and can request missing or newer LSAs using LSR packets. The neighbor responds with Link-State Update packets containing the requested information. Database Description packets summarize the contents of a router’s link-state database, while Hello packets establish and maintain neighbor relationships. Link-State Acknowledgment packets confirm receipt of LSAs. Understanding the five OSPF packet types is useful when diagnosing adjacency and database-synchronization problems.

Question: 46. Which Junos configuration mode is used to make changes to the candidate configuration before they are activated?

1. Shell mode
   2. Operational mode
   3. Configuration mode
   4. Monitor mode

Correct Answer: 3. Configuration mode

Explanation:

Junos uses configuration mode for creating, modifying, and reviewing the candidate configuration. Changes made in this mode are not normally active in the forwarding configuration until they are committed. This separation allows administrators to review and validate changes before applying them. Operational mode is primarily used for monitoring and troubleshooting the running device. Junos also provides commands such as commit check to validate configuration syntax and commit to activate changes. Understanding the separation between operational and configuration modes is fundamental to safe Junos administration and helps reduce accidental changes to production services.

Question: 47. Which routing protocol is classified as a distance-vector protocol and traditionally uses hop count as its routing metric?

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

Correct Answer: 2. RIP

Explanation:

Routing Information Protocol, or RIP, is a distance-vector routing protocol that traditionally uses hop count as its primary routing metric. Each router exchanges routing information with neighbors and selects paths based largely on the number of router hops. RIP has a relatively small maximum hop-count limit, which limits its suitability for large networks. OSPF and IS-IS are link-state protocols, while BGP is a path-vector protocol that uses multiple attributes for route selection. Although RIP is less common in modern large-scale enterprise and service-provider networks, understanding its behavior remains useful for networking fundamentals and certification exams.

Question: 48. What is the primary purpose of a Junos routing policy?

1. Replace the forwarding engine
   2. Establish Ethernet cabling standards
   3. Control how routes are imported, exported, accepted, rejected, or modified
   4. Provide physical interface redundancy

Correct Answer: 3. Control how routes are imported, exported, accepted, rejected, or modified

Explanation:

Junos routing policies provide a flexible mechanism for controlling route processing. Policies can match characteristics such as protocol, prefix, community, route attributes, or other criteria and then apply actions such as accepting, rejecting, modifying, or changing route attributes. Routing policies are commonly used with BGP, OSPF, IS-IS, and route redistribution. They allow administrators to implement deliberate routing behavior rather than relying only on default protocol decisions. Routing policies do not replace forwarding hardware or provide physical link redundancy. Understanding policy terms, match conditions, and actions is essential for Junos routing configuration and troubleshooting.

Question: 49. Which BGP community is commonly used to prevent a route from being advertised to BGP peers?

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

Correct Answer: 4. no-advertise

Explanation:

The well-known BGP no-advertise community indicates that a route should not be advertised to any BGP peer. This provides a mechanism for controlling route propagation through BGP policy. The no-export community has a different scope: it generally prevents a route from being advertised outside the local autonomous system or confederation context according to the applicable rules. The internet community indicates that the route may be advertised to all BGP peers, while local-AS has specific behavior associated with confederations or local-AS configurations. Communities are therefore powerful tools for implementing routing policy.

Question: 50. Which IPv4 prefix is reserved for private addressing in the 172.16.0.0 range?

1. 172.0.0.0/12
   2. 172.16.0.0/12
   3. 172.32.0.0/12
   4. 172.16.0.0/16

Correct Answer: 2. 172.16.0.0/12

Explanation:

The IPv4 private address block 172.16.0.0/12 covers addresses from 172.16.0.0 through 172.31.255.255. These addresses are intended for private network use and are not globally routable on the public Internet. The other private IPv4 blocks are 10.0.0.0/8 and 192.168.0.0/16. The distinction between 172.16.0.0/12 and smaller prefixes such as /16 is important because the entire /12 range is reserved for private addressing. Private addresses are commonly used inside enterprise networks and may require NAT or another mechanism when communicating with public networks.

Question: 51. What is the primary function of an OSPF Link-State Update packet?

1. Carry one or more LSAs to neighboring routers
   2. Establish the TCP session used by OSPF
   3. Assign IP addresses to OSPF interfaces
   4. Negotiate Ethernet link aggregation

Correct Answer: 1. Carry one or more LSAs to neighboring routers

Explanation:

OSPF Link-State Update packets carry one or more Link-State Advertisements from one router to another. They are used to distribute topology information throughout the appropriate OSPF flooding scope so that routers can maintain synchronized link-state databases. A router may send Link-State Updates in response to Link-State Requests or as part of normal LSA flooding. OSPF does not use TCP for neighbor communication, and IP address assignment is outside OSPF’s function. Ethernet link aggregation is handled by mechanisms such as LACP. Correctly understanding OSPF packet types helps identify where adjacency or database synchronization is failing.

Question: 52. Which Junos feature allows a device to use multiple routing tables for logically separated networks?

1. Interface statistics
   2. Routing instances
   3. Firewall counters
   4. Interface groups

Correct Answer: 2. Routing instances

Explanation:

Junos routing instances allow multiple logically separate routing environments to exist on the same physical device. Each routing instance can have its own routing table and associated interfaces, allowing traffic from different customers, departments, or services to remain logically separated. This capability is particularly useful in service-provider and multi-tenant environments. Routing instances can be configured for different purposes, including virtual routing and Layer 3 VPN services. Interface statistics and firewall counters provide operational information but do not create independent routing tables. Routing instances therefore provide the logical separation required for multiple routing domains.

Question: 53. Which BGP session type is normally established between routers within the same autonomous system?

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

Correct Answer: 3. iBGP

Explanation:

Internal BGP, or iBGP, is used to exchange BGP routing information between BGP speakers within the same autonomous system. iBGP allows routes learned through external BGP sessions to be distributed internally according to BGP’s route-propagation rules. Because of the traditional iBGP full-mesh requirement, larger networks commonly use route reflectors or confederations to improve scalability. eBGP is normally used between different autonomous systems. OSPF and IS-IS are separate interior gateway protocols rather than BGP session types. Understanding iBGP behavior is especially important when troubleshooting why externally learned routes are not reaching other internal BGP routers.

Question: 54. Which IPv6 mechanism allows a host to determine whether an IPv6 address is already in use before assigning it to an interface?

1. DHCP relay
   2. Router Advertisement
   3. Duplicate Address Detection
   4. ARP

Correct Answer: 3. Duplicate Address Detection

Explanation:

Duplicate Address Detection, or DAD, is an IPv6 Neighbor Discovery mechanism used to determine whether an address is already in use on the local link before a node assigns it to an interface. The process uses Neighbor Solicitation messages and appropriate Neighbor Advertisement responses. Detecting duplicate addresses helps prevent two IPv6 nodes from unintentionally using the same address. ARP is an IPv4 protocol and is not used for IPv6 address resolution. Router Advertisements provide network configuration information, while DHCP relay forwards DHCP messages between network segments. DAD is therefore specifically associated with checking IPv6 address uniqueness.

Question: 55. Which Junos command is useful for examining the entries in an Ethernet switching table?

1. show ethernet-switching table
   2. show bgp summary
   3. show route advertising-protocol
   4. show ospf database

Correct Answer: 1. show ethernet-switching table

Explanation:

The show ethernet-switching table command displays Layer 2 MAC-address learning information on supported Junos switching platforms. It can help administrators determine which MAC addresses have been learned and the interfaces or VLAN contexts associated with them. This information is useful when troubleshooting switching behavior, unexpected flooding, or connectivity problems within a Layer 2 network. show bgp summary focuses on BGP peers, while OSPF database commands display link-state information. Route-advertising commands are used to examine routing-protocol advertisements rather than Layer 2 MAC learning. The switching table is therefore a key operational resource for Ethernet troubleshooting.

Question: 56. What is the main purpose of the OSPF dead interval?

1. Determine the maximum number of OSPF routes
   2. Determine how long a router can go without receiving Hello packets before declaring a neighbor down
   3. Set the administrative distance of OSPF
   4. Control BGP route advertisement

Correct Answer: 2. Determine how long a router can go without receiving Hello packets before declaring a neighbor down

Explanation:

The OSPF dead interval defines how long a router waits without receiving expected Hello packets before considering an OSPF neighbor unavailable. The Hello and dead intervals must generally be compatible between neighboring routers for an adjacency to form successfully. If the dead interval expires, the router removes the neighbor relationship and recalculates the affected routes as necessary. The dead interval does not define the number of routes, set BGP behavior, or directly determine administrative preference. When troubleshooting an OSPF adjacency that repeatedly disappears, checking Hello and dead-interval compatibility is an important step.

Question: 57. Which routing protocol uses TCP as its transport protocol?

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

Correct Answer: 3. BGP

Explanation:

BGP uses TCP as its transport protocol and normally establishes sessions using TCP port 179. The use of TCP provides reliable, ordered delivery of BGP messages between peers. OSPF uses IP protocol number 89 directly rather than TCP or UDP, while IS-IS operates directly at the data-link layer. RIP traditionally uses UDP, commonly with port 520 for RIPv2. Understanding the transport mechanisms used by routing protocols is useful when troubleshooting firewall filters, connectivity, and session establishment. For BGP, successful IP reachability alone is not enough if TCP port 179 is blocked or the peer parameters are incorrect.

Question: 58. Which Junos command can be used to inspect the ARP table for IPv4 neighbors?

1. show arp
   2. show route protocol bgp
   3. show ipv6 neighbors
   4. show ospf neighbor

Correct Answer: 1. show arp

Explanation:

The show arp command is used on Junos devices to display IPv4-to-MAC address mappings learned through the Address Resolution Protocol. The ARP table can help determine whether a device has successfully resolved the Layer 2 address associated with a directly connected IPv4 neighbor. This is particularly useful when an IP route exists but communication with a local host is unsuccessful. IPv6 neighbor information is handled through IPv6 Neighbor Discovery rather than ARP. OSPF and BGP commands provide routing-protocol information and do not directly display the IPv4 ARP cache.

Question: 59. Which BGP attribute is generally preferred when it has a higher value and is used to influence outbound traffic within an autonomous system?

1. MED
   2. Local preference
   3. Origin
   4. AS path length

Correct Answer: 2. Local preference

Explanation:

Local preference is used within an autonomous system to influence which BGP exit point should be preferred for outbound traffic. When comparing otherwise eligible routes, a higher local-preference value is generally preferred. Because the attribute is propagated through iBGP, administrators can use it to establish consistent outbound-routing policies across multiple routers. MED generally has the opposite preference direction, with lower values commonly preferred, and it is primarily used to influence inbound path selection from a neighboring AS. AS path length and origin are separate BGP decision factors. Local preference is therefore a key tool for outbound traffic engineering.

Question: 60. What is the primary purpose of the Junos commit check command?

1. Immediately activate the candidate configuration
   2. Reboot the Routing Engine
   3. Display the forwarding table
   4. Validate the candidate configuration without activating it

Correct Answer: 4. Validate the candidate configuration without activating it

Explanation:

The commit check command validates the candidate configuration for syntax and configuration consistency without actually committing the changes to the active configuration. It is useful as a safety step before applying changes, particularly when working with complex routing, interface, policy, or service configurations. A successful check does not itself activate the configuration; the administrator must perform a normal commit afterward if the changes are ready to be applied. This distinction is important in Junos because configuration mode provides a controlled workflow in which changes can be reviewed and validated before becoming operational.