{"id":15689,"date":"2026-09-18T06:23:36","date_gmt":"2026-09-18T06:23:36","guid":{"rendered":"https:\/\/www.examlabs.com\/certification\/?p=15689"},"modified":"2026-09-18T06:23:36","modified_gmt":"2026-09-18T06:23:36","slug":"juniper-jn0-664-practice-test-questions-and-exam-dumps-part11-q201-220","status":"publish","type":"post","link":"https:\/\/www.examlabs.com\/certification\/juniper-jn0-664-practice-test-questions-and-exam-dumps-part11-q201-220\/","title":{"rendered":"Juniper JN0-664 Practice Test Questions and Exam Dumps Part11 Q201-220"},"content":{"rendered":"

<\/h1>\n

View Full <\/b>Juniper JN0-664 Exam Dumps<\/b><\/a> and Practice Test Dumps.<\/b><\/h2>\n

 <\/p>\n

Question 201<\/b><\/h2>\n

Which Junos command displays current ARP table entries?<\/b><\/p>\n

    \n
  1. show arp<\/span><\/li>\n
  2. show ipv6 neighbors<\/span><\/li>\n
  3. show interfaces media<\/span><\/li>\n
  4. show route summary<\/span><\/li>\n<\/ol>\n

    Correct Answer: 1<\/b><\/p>\n

    Explanation:<\/b><\/p>\n

    The show arp command displays IPv4 address-to-MAC address mappings maintained by the device. ARP allows an IPv4 device to discover the Layer 2 hardware address associated with a directly reachable IPv4 destination. The resulting mappings can be learned dynamically or configured statically, depending on the environment. Administrators commonly use this command when investigating local IPv4 connectivity, incomplete address resolution, or unexpected hardware-address mappings. It is specifically associated with IPv4 ARP information, whereas IPv6 uses Neighbor Discovery instead. Reviewing the ARP table can therefore help determine whether Layer 3 neighbors are being resolved correctly at the local Ethernet level.<\/span><\/p>\n

    Question 202<\/b><\/h2>\n

    Which IPv6 protocol replaces ARP for address resolution?<\/b><\/p>\n

      \n
    1. DHCPv6<\/span><\/li>\n
    2. ICMPv6 Neighbor Discovery<\/span><\/li>\n
    3. IPv6 Router Advertisement<\/span><\/li>\n
    4. Multicast Listener Discovery<\/span><\/li>\n<\/ol>\n

      Correct Answer: 2<\/b><\/p>\n

      Explanation:<\/b><\/p>\n

      IPv6 does not use ARP for discovering the Layer 2 address associated with an IPv6 neighbor. Instead, Neighbor Discovery functionality carried through ICMPv6 provides address-resolution capabilities. A host can send a Neighbor Solicitation message to determine the link-layer address of another IPv6 node, while Neighbor Advertisement messages provide the corresponding response. Neighbor Discovery also supports additional functions such as router discovery and neighbor reachability detection. DHCPv6 provides configuration information, while Router Advertisement is one specific Neighbor Discovery message type. MLD handles IPv6 multicast membership. Therefore, ICMPv6 Neighbor Discovery provides the IPv6 mechanism that replaces the ARP role.<\/span><\/p>\n

      Question 203<\/b><\/h2>\n

      Which Junos command examines optical transceiver diagnostic information?<\/b><\/p>\n

        \n
      1. show interfaces diagnostics optics<\/span><\/li>\n
      2. show chassis alarms<\/span><\/li>\n
      3. show system users<\/span><\/li>\n
      4. show route receive-protocol<\/span><\/li>\n<\/ol>\n

        Correct Answer: 1<\/b><\/p>\n

        Explanation:<\/b><\/p>\n

        The show interfaces diagnostics optics command provides diagnostic information about supported optical transceivers. Depending on the hardware and optic, the output can include information such as optical transmit power, receive power, module temperature, voltage, and other digital diagnostic monitoring values. These details are useful when investigating fiber connectivity problems, degraded optical performance, or potential transceiver issues. The command is different from general interface-status commands because it focuses specifically on optical-module diagnostics. Availability and displayed fields can vary according to platform and transceiver capabilities. Engineers often use this information alongside interface statistics when troubleshooting physical-layer problems.<\/span><\/p>\n

        Question 204<\/b><\/h2>\n

        What does the Junos commit confirmed feature provide?<\/b><\/p>\n

          \n
        1. Automatic configuration rollback after timeout<\/span><\/li>\n
        2. Permanent activation without validation<\/span><\/li>\n
        3. Immediate deletion of candidate changes<\/span><\/li>\n
        4. Automatic interface speed negotiation<\/span><\/li>\n<\/ol>\n

          Correct Answer: 1<\/b><\/p>\n

          Explanation:<\/b><\/p>\n

          The Junos commit confirmed mechanism provides a safety mechanism for remote configuration changes. It activates the candidate configuration temporarily while starting a confirmation timer. If the administrator does not issue a regular confirmation commit before the timer expires, Junos automatically rolls back to the previous committed configuration. This is particularly valuable when making changes that could accidentally disrupt management connectivity. For example, a remotely administered interface or routing modification can be tested without permanently risking loss of access. The feature therefore provides an automatic recovery path when the administrator cannot confirm that the new configuration is functioning correctly.<\/span><\/p>\n

          Question 205<\/b><\/h2>\n

          Which BGP attribute identifies the original source of route information?<\/b><\/p>\n

            \n
          1. Aggregator<\/span><\/li>\n
          2. Originator ID<\/span><\/li>\n
          3. Origin<\/span><\/li>\n
          4. Cluster ID<\/span><\/li>\n<\/ol>\n

            Correct Answer: 3<\/b><\/p>\n

            Explanation:<\/b><\/p>\n

            The BGP Origin attribute indicates how a route entered BGP. Its values identify whether the prefix originated through an interior gateway protocol, was introduced through an external mechanism, or has an incomplete origin indication. The attribute participates in BGP best-path selection when multiple routes are otherwise comparable. Originator ID and Cluster ID are associated with route-reflection behavior, while Aggregator can identify information related to route aggregation. Understanding the distinction among these attributes is important when analyzing why BGP selected one route over another. The Origin attribute specifically describes the route’s origin status rather than identifying a particular BGP speaker.<\/span><\/p>\n

            Question 206<\/b><\/h2>\n

            Which Junos configuration statement defines a static IPv4 route?<\/b><\/p>\n

              \n
            1. protocols static<\/span><\/li>\n
            2. routing-options static<\/span><\/li>\n
            3. forwarding-options static<\/span><\/li>\n
            4. interfaces static<\/span><\/li>\n<\/ol>\n

              Correct Answer: 2<\/b><\/p>\n

              Explanation:<\/b><\/p>\n

              In Junos, static routes are configured under the routing-options hierarchy using the static routing configuration. A static route provides a manually specified path toward a destination prefix rather than relying on a dynamic routing protocol to discover that path. Administrators can define a next hop, interface, or other supported forwarding behavior depending on the route design. Static routes are commonly used for simple connectivity, default routing, backup paths, or specific prefixes that do not require dynamic discovery. The protocols hierarchy is generally used for routing protocols themselves, while routing-options contains broader routing configuration including static routes.<\/span><\/p>\n

              Question 207<\/b><\/h2>\n

              Which feature prevents IPv4 packets using invalid source addresses?<\/b><\/p>\n

                \n
              1. DHCP snooping<\/span><\/li>\n
              2. Unicast Reverse Path Forwarding<\/span><\/li>\n
              3. Ethernet OAM<\/span><\/li>\n
              4. Link aggregation<\/span><\/li>\n<\/ol>\n

                Correct Answer: 2<\/b><\/p>\n

                Explanation:<\/b><\/p>\n

                Unicast Reverse Path Forwarding, commonly called uRPF, can help reduce IP source-address spoofing by checking whether the source address of an incoming packet has a valid route through the expected interface. Depending on the configured uRPF mode, packets that fail the reverse-path validation can be discarded. This provides a security control at the routing or forwarding level. DHCP snooping protects DHCP-related behavior, Ethernet OAM monitors Ethernet operations, and link aggregation combines physical interfaces. uRPF is therefore specifically relevant when an administrator wants to validate whether incoming source addresses are consistent with the device’s routing information.<\/span><\/p>\n

                Question 208<\/b><\/h2>\n

                Which protocol provides IPv6 addresses through DHCP-based configuration?<\/b><\/p>\n

                  \n
                1. DHCPv4<\/span><\/li>\n
                2. DHCPv6<\/span><\/li>\n
                3. BOOTP<\/span><\/li>\n
                4. PPPoE<\/span><\/li>\n<\/ol>\n

                  Correct Answer: 2<\/b><\/p>\n

                  Explanation:<\/b><\/p>\n

                  DHCPv6 provides dynamic host configuration services for IPv6 networks. It can supply information such as IPv6 addresses and other configuration parameters, depending on the deployment model. DHCPv6 differs from DHCPv4 because IPv6 hosts use Neighbor Discovery and Router Advertisements for several foundational network functions. In some designs, Router Advertisements can indicate that hosts should obtain additional configuration through DHCPv6. BOOTP is an older host-configuration protocol, while DHCPv4 serves IPv4 environments. PPPoE provides a method for carrying network traffic over Ethernet-based access sessions. DHCPv6 is therefore the protocol specifically designed for DHCP-based IPv6 configuration.<\/span><\/p>\n

                  Question 209<\/b><\/h2>\n

                  Which multicast feature limits unnecessary Layer 2 multicast flooding?<\/b><\/p>\n

                    \n
                  1. IGMP snooping<\/span><\/li>\n
                  2. Ethernet loop detection<\/span><\/li>\n
                  3. ARP inspection<\/span><\/li>\n
                  4. Port authentication<\/span><\/li>\n<\/ol>\n

                    Correct Answer: 1<\/b><\/p>\n

                    Explanation:<\/b><\/p>\n

                    IGMP snooping allows a Layer 2 switch to examine IGMP membership messages and learn which ports have interested IPv4 multicast receivers. Instead of flooding multicast traffic broadly across every port in the broadcast domain, the switch can forward the traffic toward interfaces associated with active multicast memberships. This can reduce unnecessary bandwidth consumption and improve multicast efficiency on switched networks. IGMP snooping is different from multicast routing protocols because the switch is observing host membership information rather than establishing an inter-router multicast distribution tree. The feature is particularly useful in networks carrying applications such as streaming, conferencing, or other one-to-many IPv4 traffic.<\/span><\/p>\n

                    Question 210<\/b><\/h2>\n

                    Which Junos interface unit represents a logical interface identifier?<\/b><\/p>\n

                      \n
                    1. ge-0\/0\/0<\/span><\/li>\n
                    2. ge-0\/0\/0.0<\/span><\/li>\n
                    3. xe-1\/2\/3<\/span><\/li>\n
                    4. et-0\/0\/1<\/span><\/li>\n<\/ol>\n

                      Correct Answer: 2<\/b><\/p>\n

                      Explanation:<\/b><\/p>\n

                      In Junos, a logical interface unit is represented by a unit number following the physical interface name, such as ge-0\/0\/0.0. The physical interface identifies the hardware port, while the unit identifies a logical interface configured on that physical interface. Different units can support separate logical configurations depending on the interface type and service requirements. This structure is important because many Junos Layer 3 configurations are applied to logical units rather than directly to the physical interface. The other examples represent physical interface identifiers without the logical-unit notation shown in the correct answer.<\/span><\/p>\n

                      Question 211<\/b><\/h2>\n

                      Which Junos command shows neighboring OSPF router adjacencies?<\/b><\/p>\n

                        \n
                      1. show ospf neighbor<\/span><\/li>\n
                      2. show ospf database<\/span><\/li>\n
                      3. show ospf statistics<\/span><\/li>\n
                      4. show ospf overview<\/span><\/li>\n<\/ol>\n

                        Correct Answer: 1<\/b><\/p>\n

                        Explanation:<\/b><\/p>\n

                        The show ospf neighbor command displays information about OSPF neighbors and their adjacency states. This makes it useful when determining whether a local router has successfully established communication with other OSPF-speaking devices. The output can provide information such as neighboring router identifiers, interface relationships, adjacency states, and related timing details. Administrators commonly use this command during OSPF troubleshooting when routes are missing or topology information appears incomplete. The OSPF database command serves a different purpose by displaying link-state information. Neighbor status should generally be checked first when investigating whether OSPF peers are successfully forming the expected relationships.<\/span><\/p>\n

                        Question 212<\/b><\/h2>\n

                        Which BGP attribute helps prevent routing loops through route reflection?<\/b><\/p>\n

                          \n
                        1. Local Preference<\/span><\/li>\n
                        2. Originator ID<\/span><\/li>\n
                        3. MED<\/span><\/li>\n
                        4. Atomic Aggregate<\/span><\/li>\n<\/ol>\n

                          Correct Answer: 2<\/b><\/p>\n

                          Explanation:<\/b><\/p>\n

                          The BGP Originator ID attribute is used within route-reflection environments to help identify the router that originally generated a reflected route. A route reflector can include this attribute when reflecting routes learned from clients. This information helps prevent certain routing loops because a receiving router can recognize that it originally originated the route. Originator ID should not be confused with Local Preference or MED, which influence route selection, or Atomic Aggregate, which carries information associated with aggregation. Understanding route-reflector attributes is useful when troubleshooting internal BGP designs where multiple routers exchange reflected routes.<\/span><\/p>\n

                          Question 213<\/b><\/h2>\n

                          Which Ethernet feature detects faults across connected Ethernet links?<\/b><\/p>\n

                            \n
                          1. Ethernet OAM<\/span><\/li>\n
                          2. DHCP relay<\/span><\/li>\n
                          3. Route reflection<\/span><\/li>\n
                          4. Multicast routing<\/span><\/li>\n<\/ol>\n

                            Correct Answer: 1<\/b><\/p>\n

                            Explanation:<\/b><\/p>\n

                            Ethernet Operations, Administration, and Maintenance, commonly called Ethernet OAM, provides mechanisms for monitoring and troubleshooting Ethernet connectivity. OAM can help operators detect faults and evaluate the operational condition of Ethernet links or services. It is especially useful in provider and enterprise environments where Ethernet connectivity may extend across multiple devices and physical segments. Ethernet OAM differs from routing protocols because it focuses on Ethernet service and link operations rather than calculating Layer 3 paths. DHCP relay forwards client configuration requests between network segments, route reflection distributes BGP information internally, and multicast routing manages multicast forwarding between routers.<\/span><\/p>\n

                            Question 214<\/b><\/h2>\n

                            Which Junos command displays current chassis environmental conditions?<\/b><\/p>\n

                              \n
                            1. show chassis environment<\/span><\/li>\n
                            2. show system storage<\/span><\/li>\n
                            3. show interfaces descriptions<\/span><\/li>\n
                            4. show configuration groups<\/span><\/li>\n<\/ol>\n

                              Correct Answer: 1<\/b><\/p>\n

                              Explanation:<\/b><\/p>\n

                              The show chassis environment command displays environmental information associated with the device chassis. Depending on platform support, this can include conditions such as temperature readings, fan states, power-supply status, and other hardware environmental information. Such information is valuable when diagnosing hardware alarms or determining whether operating conditions may affect device stability. The command differs from storage, interface-description, and configuration-group commands because it focuses on physical chassis health. Regular environmental monitoring can help identify developing hardware problems before they cause more significant service disruption.<\/span><\/p>\n

                              Question 215<\/b><\/h2>\n

                              Which BGP mechanism allows simultaneous installation of multiple paths?<\/b><\/p>\n

                                \n
                              1. BGP Multipath<\/span><\/li>\n
                              2. Route aggregation<\/span><\/li>\n
                              3. Community tagging<\/span><\/li>\n
                              4. AS-path filtering<\/span><\/li>\n<\/ol>\n

                                Correct Answer: 1<\/b><\/p>\n

                                Explanation:<\/b><\/p>\n

                                BGP Multipath allows multiple eligible BGP routes to the same destination to be installed for forwarding when they satisfy the required multipath conditions. Instead of using only one selected route, the device can maintain several forwarding paths, which can improve traffic distribution and path utilization. The exact requirements for multipath installation depend on the platform and configuration, including attributes that may need to match or satisfy specific conditions. BGP Multipath differs from Add-Path: Add-Path concerns advertising multiple paths to peers, whereas multipath concerns using multiple eligible paths locally for forwarding. This distinction is important in advanced BGP designs.<\/span><\/p>\n

                                Question 216<\/b><\/h2>\n

                                Which Junos feature stores configuration changes for later activation?<\/b><\/p>\n

                                  \n
                                1. Candidate configuration<\/span><\/li>\n
                                2. Forwarding database<\/span><\/li>\n
                                3. Routing information base<\/span><\/li>\n
                                4. Interface statistics<\/span><\/li>\n<\/ol>\n

                                  Correct Answer: 1<\/b><\/p>\n

                                  Explanation:<\/b><\/p>\n

                                  The Junos candidate configuration stores configuration changes before they are committed and activated. Administrators normally enter configuration mode, modify the candidate configuration, review the proposed changes, and then commit them. This separation between candidate and active configuration provides an important safety mechanism because changes can be examined or discarded before they affect the running device. The forwarding database contains Layer 2 forwarding information, while the routing information base contains routing information used for path selection. Interface statistics describe operational traffic and counters. The candidate configuration is specifically associated with preparing and reviewing changes before activation.<\/span><\/p>\n

                                  Question 217<\/b><\/h2>\n

                                  Which security feature validates source addresses using routing information?<\/b><\/p>\n

                                    \n
                                  1. MAC authentication<\/span><\/li>\n
                                  2. uRPF<\/span><\/li>\n
                                  3. BPDU filtering<\/span><\/li>\n
                                  4. DHCP relay<\/span><\/li>\n<\/ol>\n

                                    Correct Answer: 2<\/b><\/p>\n

                                    Explanation:<\/b><\/p>\n

                                    Unicast Reverse Path Forwarding, or uRPF, validates incoming packet source addresses against routing information. The device checks whether the source address has a valid route and, depending on the configured mode, whether that route points through the expected incoming interface. This helps reduce traffic using forged or spoofed source addresses. uRPF can therefore provide an important anti-spoofing control at network boundaries. MAC authentication controls access based on endpoint identity, BPDU filtering manages spanning-tree protocol frames, and DHCP relay forwards address-assignment messages. These mechanisms solve different security or networking problems rather than performing reverse-path source validation.<\/span><\/p>\n

                                    Question 218<\/b><\/h2>\n

                                    Which automation interface commonly uses NETCONF with YANG models?<\/b><\/p>\n

                                      \n
                                    1. Model-driven management<\/span><\/li>\n
                                    2. Console terminal access<\/span><\/li>\n
                                    3. Ethernet OAM<\/span><\/li>\n
                                    4. Spanning-tree control<\/span><\/li>\n<\/ol>\n

                                      Correct Answer: 1<\/b><\/p>\n

                                      Explanation:<\/b><\/p>\n

                                      Model-driven management commonly uses NETCONF together with YANG-defined data models to provide structured configuration and operational data exchange. YANG describes the organization and relationships of configuration and state information, while NETCONF provides a protocol framework for manipulating that structured information. This approach can make network automation more consistent than relying exclusively on interactive CLI commands. Console access provides direct administrative interaction, Ethernet OAM handles Ethernet operational monitoring, and spanning-tree protocols manage Layer 2 topology. Model-driven management is therefore associated with programmatic, structured network configuration and operational-state retrieval.<\/span><\/p>\n

                                      Question 219<\/b><\/h2>\n

                                      Which Junos mechanism can restore configuration using numbered rollback files?<\/b><\/p>\n

                                        \n
                                      1. Configuration rollback<\/span><\/li>\n
                                      2. Packet mirroring<\/span><\/li>\n
                                      3. Route redistribution<\/span><\/li>\n
                                      4. Interface policing<\/span><\/li>\n<\/ol>\n

                                        Correct Answer: 1<\/b><\/p>\n

                                        Explanation:<\/b><\/p>\n

                                        Junos maintains previous committed configurations that can be accessed through the rollback mechanism. Administrators can use numbered rollback configurations to review or restore an earlier configuration state when required. This is useful after an unsuccessful change because it provides access to previously committed configuration versions. Rollback is distinct from the rescue configuration, although both can support configuration recovery. Packet mirroring copies traffic for analysis, route redistribution exchanges routes between routing protocols, and interface policing controls traffic rates. Configuration rollback specifically addresses recovery or comparison of earlier Junos configuration states.<\/span><\/p>\n

                                        Question 220<\/b><\/h2>\n

                                        Which protocol distributes routing information between separate autonomous systems?<\/b><\/p>\n

                                          \n
                                        1. OSPF<\/span><\/li>\n
                                        2. IS-IS<\/span><\/li>\n
                                        3. BGP<\/span><\/li>\n
                                        4. RIP<\/span><\/li>\n<\/ol>\n

                                          Correct Answer: 3<\/b><\/p>\n

                                          Explanation:<\/b><\/p>\n

                                          Border Gateway Protocol, or BGP, is designed to exchange routing information between autonomous systems. It is therefore classified as an exterior gateway protocol and forms the foundation of interdomain Internet routing. BGP uses policy-driven path selection rather than simply choosing paths based on a single metric. OSPF and IS-IS are interior gateway protocols generally used within an autonomous system, while RIP is also an interior routing protocol designed for smaller routing environments. BGP can exchange information between external peers and can apply routing policies based on attributes such as AS path, local preference, origin, and other supported characteristics.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

                                          View Full Juniper JN0-664 Exam Dumps and Practice Test Dumps.   Question 201 Which Junos command displays current ARP table entries? show arp show ipv6 neighbors show interfaces media show route summary Correct Answer: 1 Explanation: The show arp command displays IPv4 address-to-MAC address mappings maintained by the device. ARP allows an IPv4 device to […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[1648,1647],"tags":[],"_links":{"self":[{"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/posts\/15689"}],"collection":[{"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/comments?post=15689"}],"version-history":[{"count":1,"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/posts\/15689\/revisions"}],"predecessor-version":[{"id":15705,"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/posts\/15689\/revisions\/15705"}],"wp:attachment":[{"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/media?parent=15689"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/categories?post=15689"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/tags?post=15689"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}