Juniper JN0-650 Practice Test 66
Question 650
A client leaves a video group yet traffic persists to its access port. Which technical principle BEST explains the IGMPv2 membership report and leave decision?
- IPv4 multicast destination ranges are group identifiers rather than ordinary host addresses.
- IPv6 multicast uses ff00::/8 scoped addressing separate from IPv4 group syntax.
- IGMP expresses host interest in groups while routing protocols move traffic between subnets.
- 802.1X host-mode behavior controls whether access applies per endpoint or per port.
Explanation
Correct Answer
C:IGMP expresses host interest in groups while routing protocols move traffic between subnets. In this situation, the relevant action is to verify IGMPv2 membership joins leaves and querier operation for the intended subnet.
Incorrect Answers
A:IPv4 multicast destination ranges are group identifiers rather than ordinary host addresses. That principle is related to IPv4 multicast group address versus unicast, not the main IGMPv2 membership report and leave choice. Treating IGMP as an interrouter PIM replacement prevents routed multicast delivery.
B:IPv6 multicast uses ff00::/8 scoped addressing separate from IPv4 group syntax. That principle is related to IPv6 multicast scope and group use, not the main IGMPv2 membership report and leave choice. Treating IGMP as an interrouter PIM replacement prevents routed multicast delivery.
D:802.1X host-mode behavior controls whether access applies per endpoint or per port. That principle is related to 802.1X multi-supplicant port control, not the main IGMPv2 membership report and leave choice. Treating IGMP as an interrouter PIM replacement prevents routed multicast delivery.
Question 651
Two devices are candidates to send periodic IGMP membership queries. Select TWO statements that correctly combine the IGMP querier on subscriber VLAN implementation, its evidence, or its governing principle.
- Ensure a functioning IGMP querier exists and validate election or participation.
- Align source reachability and any approved multicast RPF policy with actual topology.
- Periodic queries refresh receiver membership and groups do not unexpectedly expire.
- Increase OSPF Dead interval and assume it generates IGMP queries.
- Use IGMPv3-capable receivers and source-specific membership where applicable.
Explanation
Correct Answers
A:Ensure a functioning IGMP querier exists and validate election or participation. This is the intended implementation action for IGMP querier on subscriber VLAN.
C:Periodic queries refresh receiver membership and groups do not unexpectedly expire. This is direct observable evidence for IGMP querier on subscriber VLAN.
Incorrect Answers
B:Align source reachability and any approved multicast RPF policy with actual topology. This belongs to Multicast source route policy and RPF, not the specified IGMP querier on subscriber VLAN operation. IGMP queriers maintain host membership state on a local multicast segment.
D:Increase OSPF Dead interval and assume it generates IGMP queries. This would not be an appropriate IGMP querier on subscriber VLAN decision. Without an effective querier snooping tables can lose active receiver ports.
E:Use IGMPv3-capable receivers and source-specific membership where applicable. This belongs to IGMPv3 source include mode, not the specified IGMP querier on subscriber VLAN operation. IGMP queriers maintain host membership state on a local multicast segment.
Question 652
Two internal OSPF paths to a data center are both operational but the slower path wins. Which configuration or operational step BEST meets the stated requirement?
- Apply a correct address-range summary on the intended ABR with covering-prefix review.
- Use BGP MED on an unrelated external peer to control the internal OSPF link metric.
- Use a consistent OSPF reference-bandwidth policy across the intended routing domain.
- Assign deliberate OSPF interface costs and check the total path metric.
Explanation
Correct Answer
D:Assign deliberate OSPF interface costs and check the total path metric. OSPF SPF selects lowest cumulative link cost subject to policy and availability. The expected validation is that active routes prefer the expected lowest cumulative OSPF metric.
Incorrect Answers
A:Apply a correct address-range summary on the intended ABR with covering-prefix review. This addresses OSPF interarea route summarization rather than the required OSPF path cost selection decision. OSPF SPF selects lowest cumulative link cost subject to policy and availability.
B:Use BGP MED on an unrelated external peer to control the internal OSPF link metric. This is a risky or ineffective shortcut for OSPF path cost selection. Overlooking total cost can route critical traffic over a constrained backup path.
C:Use a consistent OSPF reference-bandwidth policy across the intended routing domain. This addresses OSPF reference bandwidth and high-speed links rather than the required OSPF path cost selection decision. OSPF SPF selects lowest cumulative link cost subject to policy and availability.
Question 653
An engineer changes a transit interface cost but routes still choose an unexpected next hop. Which next investigation or correction is MOST appropriate?
- Examine show ospf3 neighbor and IPv6 link-local addresses or interface state.
- Collect show ospf neighbor detail and correlate state progression against network design.
- Use BGP MED on an unrelated external peer to control the internal OSPF link metric.
- Compare show route protocol ospf and interface metric contributions along both paths.
Explanation
Correct Answer
D:Compare show route protocol ospf and interface metric contributions along both paths. This checks whether active routes prefer the expected lowest cumulative OSPF metric.
Incorrect Answers
A:Examine show ospf3 neighbor and IPv6 link-local addresses or interface state. That check applies chiefly to OSPFv3 IPv6 link-local neighbor formation, not the current OSPF path cost selection issue. OSPF SPF selects lowest cumulative link cost subject to policy and availability.
B:Collect show ospf neighbor detail and correlate state progression against network design. That check applies chiefly to OSPF neighbor state troubleshooting workflow, not the current OSPF path cost selection issue. OSPF SPF selects lowest cumulative link cost subject to policy and availability.
C:Use BGP MED on an unrelated external peer to control the internal OSPF link metric. That bypass leaves the OSPF path cost selection issue unresolved. Overlooking total cost can route critical traffic over a constrained backup path.
Question 654
An import policy unexpectedly accepts a long private prefix because an early term matches broadly. Which next investigation or correction is MOST appropriate?
- Compare forwarding table and multiple test flow distribution.
- Test routes against the exact prefix conditions and inspect show route advertising-protocol.
- Inspect show route hidden extensive and relevant policy terms.
- Put a filter name in the peer description and assume it becomes an active policy.
Explanation
Correct Answer
B:Test routes against the exact prefix conditions and inspect show route advertising-protocol. This checks whether only sanctioned routes pass the policy and term counters identify the decision.
Incorrect Answers
A:Compare forwarding table and multiple test flow distribution. That check applies chiefly to BGP ECMP per-flow hashing, not the current Junos BGP policy term matching issue. Junos routing policy evaluates ordered terms and control-flow actions.
C:Inspect show route hidden extensive and relevant policy terms. That check applies chiefly to BGP hidden and rejected path diagnosis, not the current Junos BGP policy term matching issue. Junos routing policy evaluates ordered terms and control-flow actions.
D:Put a filter name in the peer description and assume it becomes an active policy. That bypass leaves the Junos BGP policy term matching issue unresolved. An overly general term can prevent subsequent protective terms from being reached.
Question 655
A guest portal and MAC policy compete to assign different roles to one access port. Which next investigation or correction is MOST appropriate?
- Clear every network-wide security filter before finding the conflicting session policy.
- Capture EAPOL on access link and RADIUS transactions toward AAA host.
- Test valid and invalid 802.1X plus MAC credentials across both endpoint classes.
- Compare RADIUS result port authentication status VLAN mapping and interface filter counters.
Explanation
Correct Answer
D:Compare RADIUS result port authentication status VLAN mapping and interface filter counters. This checks whether the device has the correct authorized VLAN and permitted flows according to one coherent policy.
Incorrect Answers
A:Clear every network-wide security filter before finding the conflicting session policy. That bypass leaves the Multiple access control enforcement troubleshooting issue unresolved. Mixed ACLs and fallback methods can cause access failure after a valid login.
B:Capture EAPOL on access link and RADIUS transactions toward AAA host. That check applies chiefly to 802.1X supplicant authenticator RADIUS roles, not the current Multiple access control enforcement troubleshooting issue. Authentication success does not guarantee matching VLAN mapping or permitted data-plane access.
C:Test valid and invalid 802.1X plus MAC credentials across both endpoint classes. That check applies chiefly to 802.1X versus MAC RADIUS method priority, not the current Multiple access control enforcement troubleshooting issue. Authentication success does not guarantee matching VLAN mapping or permitted data-plane access.
Question 656
Two VLAN-selection conditions match a device packet and only one should win. Select TWO statements that correctly combine the Filter-based VLAN rule precedence implementation, its evidence, or its governing principle.
- Trace each Layer 2 hop for VLAN membership tagging outer and inner tags and protection state.
- Configure compatible Multiple VLAN Registration Protocol operation on supported links.
- Duplicate the broad term and expect later specific terms to override it.
- Reorder policy terms so specific supported VLAN matches precede broad fallback actions.
- Intended guest frames match their rule and general traffic uses the appropriate default.
Explanation
Correct Answers
D:Reorder policy terms so specific supported VLAN matches precede broad fallback actions. This is the intended implementation action for Filter-based VLAN rule precedence.
E:Intended guest frames match their rule and general traffic uses the appropriate default. This is direct observable evidence for Filter-based VLAN rule precedence.
Incorrect Answers
A:Trace each Layer 2 hop for VLAN membership tagging outer and inner tags and protection state. This belongs to Layer 2 trunk VLAN mismatch diagnosis, not the specified Filter-based VLAN rule precedence operation. Filter terms are evaluated in policy order subject to terminating actions.
B:Configure compatible Multiple VLAN Registration Protocol operation on supported links. This belongs to MVRP dynamic VLAN registration, not the specified Filter-based VLAN rule precedence operation. Filter terms are evaluated in policy order subject to terminating actions.
C:Duplicate the broad term and expect later specific terms to override it. This would not be an appropriate Filter-based VLAN rule precedence decision. Broad first-match conditions can eclipse later VLAN classification terms.
Question 657
An enterprise keeps a critical management VLAN static while application VLANs are learned with MVRP. Which configuration or operational step BEST meets the stated requirement?
- Align supported outer-tag TPID and VLAN-stacking configuration across participating devices.
- Combine required static VLAN membership with deliberate dynamic registration policy.
- Configure correct trunk mode VLAN membership and tagging at both switch interfaces.
- Rename a dynamically learned VLAN to Static and assume registration lifetime changes.
Explanation
Correct Answer
B:Combine required static VLAN membership with deliberate dynamic registration policy. MVRP learned registrations have different lifecycle from explicitly configured static VLAN memberships. The expected validation is that critical VLAN stays present and dynamic VLANs appear only when advertised.
Incorrect Answers
A:Align supported outer-tag TPID and VLAN-stacking configuration across participating devices. This addresses QinQ tag protocol EtherType compatibility rather than the required MVRP static versus dynamic registration decision. MVRP learned registrations have different lifecycle from explicitly configured static VLAN memberships.
C:Configure correct trunk mode VLAN membership and tagging at both switch interfaces. This addresses 802.1Q trunk allowed VLANs rather than the required MVRP static versus dynamic registration decision. MVRP learned registrations have different lifecycle from explicitly configured static VLAN memberships.
D:Rename a dynamically learned VLAN to Static and assume registration lifetime changes. This is a risky or ineffective shortcut for MVRP static versus dynamic registration. Assuming a learned VLAN is permanently present can break traffic after withdrawals.
Question 658
A software switchover occurs and peers must avoid immediate route loss where supported. Which configuration or operational step BEST meets the stated requirement?
- Permanently disable route withdrawal because graceful restart exists.
- Match and add or delete only documented communities using supported Junos policy statements.
- Set a policy-based higher local preference for preferred internal BGP paths.
- Configure supported graceful-restart capabilities and safe timers based on design.
Explanation
Correct Answer
D:Configure supported graceful-restart capabilities and safe timers based on design. Graceful restart preserves temporary forwarding state but is not unlimited reachability assurance. The expected validation is that peers maintain only supported stale routes during a bounded restart and withdraw them when unsafe.
Incorrect Answers
A:Permanently disable route withdrawal because graceful restart exists. This is a risky or ineffective shortcut for BGP graceful restart session continuity. Excessive stale retention after a genuine failure can blackhole traffic.
B:Match and add or delete only documented communities using supported Junos policy statements. This addresses BGP communities match and deletion rather than the required BGP graceful restart session continuity decision. Graceful restart preserves temporary forwarding state but is not unlimited reachability assurance.
C:Set a policy-based higher local preference for preferred internal BGP paths. This addresses BGP LOCAL_PREF outbound exit selection rather than the required BGP graceful restart session continuity decision. Graceful restart preserves temporary forwarding state but is not unlimited reachability assurance.
Question 659
An export filter must allow only a dedicated prefix list toward a transit provider. Which configuration or operational step BEST meets the stated requirement?
- Enable compatible BGP multipath and forwarding-table load balancing where justified.
- Implement ordered Junos policy terms with prefix match and explicit accept or reject decisions.
- Restore valid next-hop reachability without indiscriminately accepting broken routes.
- Put a filter name in the peer description and assume it becomes an active policy.
Explanation
Correct Answer
B:Implement ordered Junos policy terms with prefix match and explicit accept or reject decisions. Junos routing policy evaluates ordered terms and control-flow actions. The expected validation is that only sanctioned routes pass the policy and term counters identify the decision.
Incorrect Answers
A:Enable compatible BGP multipath and forwarding-table load balancing where justified. This addresses BGP multipath equal-cost path installation rather than the required Junos BGP policy term matching decision. Junos routing policy evaluates ordered terms and control-flow actions.
C:Restore valid next-hop reachability without indiscriminately accepting broken routes. This addresses BGP next-hop reachability hidden route rather than the required Junos BGP policy term matching decision. Junos routing policy evaluates ordered terms and control-flow actions.
D:Put a filter name in the peer description and assume it becomes an active policy. This is a risky or ineffective shortcut for Junos BGP policy term matching. An overly general term can prevent subsequent protective terms from being reached.
Question 660
Two candidate routes exist but one fails import policy and another lacks a next hop. Which next investigation or correction is MOST appropriate?
- Inspect show route hidden extensive and relevant policy terms.
- Restart all OSPF neighbors before checking BGP import decisions or next-hop reachability.
- Inspect show bgp neighbor last error and BGP OPEN notification fields.
- Check BGP advertised families and show route table inet6.0 protocol bgp.
Explanation
Correct Answer
A:Inspect show route hidden extensive and relevant policy terms. This checks whether the active route reflects documented policy and any hidden route has an explained reason.
Incorrect Answers
B:Restart all OSPF neighbors before checking BGP import decisions or next-hop reachability. That bypass leaves the BGP hidden and rejected path diagnosis issue unresolved. Treating peer Established as proof every received prefix is installed masks routing failures.
C:Inspect show bgp neighbor last error and BGP OPEN notification fields. That check applies chiefly to BGP eBGP peer AS and local identity, not the current BGP hidden and rejected path diagnosis issue. BGP neighbor state and route installation are separate control-plane gates.
D:Check BGP advertised families and show route table inet6.0 protocol bgp. That check applies chiefly to BGP NLRI IPv6 unicast inet6 family, not the current BGP hidden and rejected path diagnosis issue. BGP neighbor state and route installation are separate control-plane gates.
