Cisco Certified Network Associate (CCNA) 200-301 Practice Test 45
Question 440
R1 is HSRP Active and R2 Standby. R1 loses power, but R2’s VLAN 20 SVI is operationally down after VLAN 20 was pruned from its only active trunk; R2 cannot take over HSRP while the gateway interface is down. What must be investigated first?
- Restore VLAN 20 on R2’s active trunk so its SVI becomes up/up and can assume HSRP Active state.
- Force both routers to Active permanently so traffic is load-balanced by duplicate virtual MACs.
- Change the host default gateway from the virtual address to R1 physical interface IP.
- Increase the failed router’s priority to ensure it still wins elections.
Explanation
Correct Answer
A:R2 cannot serve the virtual gateway while its HSRP interface is down. Repair VLAN 20 connectivity, verify the SVI is up/up and confirm R2 transitions to Active after R1 disappears.
Incorrect Answers
B:Running two active owners of one virtual gateway creates an unsafe state and does not solve the standby router’s failure to take over.
C:Using the failed physical gateway eliminates FHRP resilience and worsens the outage for hosts.
D:Priority cannot restore an SVI whose VLAN is absent from the only active trunk. Repair the Layer 2 VLAN path first, then validate HSRP state.
Question 441
Troubleshooting report: A recovered higher-priority router stays Standby because preempt was not enabled, even though reachability is healthy. Which finding best accounts for the behavior?
- HSRP `preempt` is not configured on the recovered higher-priority router, so the lower-priority current Active remains Active after recovery.
- The recovered router always preempts automatically in HSRP even when preempt is disabled.
- A higher-priority HSRP Standby proves its physical interface is administratively shutdown.
- Changing only the client DNS server instantly makes the recovered router Active.
Explanation
Correct Answer
A:In HSRP, priority alone does not necessarily force a returning router to take the Active role. Enable preemption only if design requires failback and consider delay to avoid oscillation during startup.
Incorrect Answers
B:HSRP takeover by a returning higher-priority standby generally requires configured preemption.
C:A router can be healthy yet remain Standby because an existing Active is not being preempted.
D:DNS choice does not control HSRP preemption or role election.
Question 442
The active router loses its WAN uplink but keeps HSRP priority unchanged, trapping users behind a gateway with no upstream path. The team should investigate which specific technical cause?
- The HSRP VIP automatically checks every upstream Internet endpoint and hands off immediately with no configured tracking.
- HSRP is not tracking WAN next-hop/interface reachability with a sufficient priority decrement; the Active keeps the virtual gateway after losing upstream service.
- The only possible cause is both routers losing the local VLAN simultaneously although the Active still owns the VIP.
- Increasing the Active HSRP priority after WAN failure ensures the backup will become Active.
Explanation
Correct Answer
B:Without an appropriate tracked object and effective priority reduction, a router can remain HSRP Active while blackholing off-site traffic. Configure tracking and verify standby takeover under WAN failure.
Incorrect Answers
A:Basic HSRP LAN hellos alone do not measure all upstream reachability failures.
C:The given distinguishing event is one Active WAN path failure without priority change.
D:Raising the failed router’s priority would work against desired failover.
Question 443
Two VRRP routers share virtual default gateway 192.0.2.254. Both connected interfaces remain up, but a new VLAN-pruning change prevents VRRP advertisements from crossing the switch link. Each router now reports Master for the same virtual gateway. Which root cause best explains the unsafe state?
- Normal VRRP preemption causes two Masters to own a virtual gateway simultaneously.
- A downstream WAN route failure makes VRRP assign a different virtual address to each peer.
- A lower-priority router can become Master only if its local DHCP scope fails.
- A Layer 2 partition prevents VRRP advertisements between peers, so both independently declare Master.
Explanation
Correct Answer
D:When VRRP advertisements cannot cross the VLAN partition, each router may believe the peer is absent and transition to Master. Restore shared VLAN connectivity and verify a single owner plus reachable peer advertisements; this is split-brain, not normal failover.
Incorrect Answers
A:VRRP is designed to have one elected Master for a reachable shared segment, not simultaneous active owners. Preemption or a priority change alone does not justify two peers continuously acting as Master.
B:A WAN routing problem can degrade the active gateway but does not cause peers on the same VLAN to cease receiving VRRP advertisements unless another connectivity issue exists. The shared virtual address is normally common to the group.
C:VRRP Master selection is not driven by DHCP scopes. Election uses VRRP advertisements and priorities, and an active neighbor normally suppresses independent Master election.
Question 444
After HSRP switchover, hosts still have the correct virtual IP 192.0.2.254 configured as their default gateway. Their ARP caches, however, incorrectly map 192.0.2.254 to R1’s physical MAC instead of the HSRP virtual MAC. Which fault best explains continued gateway loss?
- The clients hold the correct virtual MAC for the virtual IP and the backup now owns it, so the observed physical-MAC binding is expected.
- A DNS TTL for an external website dictates which Ethernet MAC is used for the local virtual gateway.
- A correct DHCP option 3 automatically corrects every manually pinned ARP cache entry without any ARP refresh.
- Clients have an incorrect stale/static ARP association for the FHRP virtual IP pointing to a physical router MAC, so ownership changes do not update their expected virtual-MAC forwarding.
Explanation
Correct Answer
D:An FHRP virtual IP is ordinarily associated with a virtual MAC. A stale or manually pinned mapping to a physical device can break reachability across failover even when the FHRP role changes correctly.
Incorrect Answers
A:The premise explicitly shows the wrong physical MAC rather than the group’s virtual MAC.
B:ARP/neighborship for the default gateway is a Layer 2 mapping, not a DNS cache lookup.
C:Correct gateway IP and stale/static ARP association are distinct concerns.
Question 445
HSRP peers on SW1 and SW2 share the same virtual IP, but pruning their control VLAN blocks interswitch hellos. Both routers become Active for the same group and hosts see unstable gateway ownership. Which root cause explains the duplicate-active condition?
- The interswitch VLAN partition prevents peers from receiving HSRP hellos, causing each to consider itself the only Active router.
- The normal Standby router automatically forwards simultaneously whenever both routers have equal priorities.
- A client ARP timeout makes a router become Active even while HSRP hellos are received normally.
- A missing static NAT rule causes HSRP to replicate the virtual IP on independent VLANs.
Explanation
Correct Answer
A:FHRP peers need a shared Layer 2 reachability context for hellos. When the common control VLAN is partitioned, they can independently claim the virtual gateway, producing a split-brain condition.
Incorrect Answers
B:HSRP is intended to elect an Active with another Standby; equal priorities alone do not normally produce two stable Active gateways when advertisements can pass.
C:ARP caching can cause delayed client MAC learning after failover but is not an election input that causes routers to miss HSRP peer advertisements.
D:NAT configuration is unrelated to the HSRP control-plane adjacency on the common VLAN.
Question 446
Half the PCs use R1's interface IP and half the virtual IP; only PCs using the physical IP fail during an R1 outage. The team should investigate which specific technical cause?
- Every host using a physical router IP remains protected because FHRP automatically moves both routers’ unique addresses.
- The group cannot be working because half the hosts using the virtual IP remain reachable.
- The problem must be a VLAN-native mismatch because some PCs use R1’s physical gateway.
- Hosts using R1’s physical interface address as default gateway are not protected by FHRP; those using the shared virtual IP survive takeover by R2.
Explanation
Correct Answer
D:Only a virtual default gateway moves to the standby router. Consistent DHCP option 3/static host gateway configuration avoids splitting clients between physical and virtual first hops.
Incorrect Answers
A:The failover applies to the virtual address, not R1’s unique IP.
B:Those hosts’ success suggests the FHRP VIP is functioning while the physical-IP users are misconfigured.
C:Different configured host gateway IPs explain the split fate directly.
Question 447
A mixed-vendor routed VLAN is supposed to provide one virtual default gateway. The Cisco router uses an HSRP group while the non-Cisco peer is configured for VRRP, so neither treats the other as its redundancy peer. What compatibility mistake prevents an actual shared active/standby group?
- The switch needs an HTTP load balancer to elect the virtual default gateway owner.
- A default IPv4 route with smaller AD guarantees that HSRP and VRRP peers exchange the same hello messages.
- The two routers use different first-hop redundancy protocols; configure a compatible common protocol supported on both peers.
- Client ARP timeouts alone prevent HSRP and VRRP from interoperating.
Explanation
Correct Answer
C:HSRP and VRRP have distinct control messages and are not automatically one redundancy group merely because they use the same virtual address. Select a common supported protocol, then verify its actual role state.
Incorrect Answers
A:An application load balancer handles server-side application traffic, not FHRP election and shared host default-gateway ownership on a LAN.
B:Administrative distance is a route-installation preference, unrelated to protocol interoperability or the format of first-hop redundancy advertisements.
D:ARP caching is a separate host-layer effect; it cannot make HSRP and VRRP advertise compatible peer state.
Question 448
A branch routing engineer is validating a repair. Earlier, clients use the real IP of R1, so a failover to R2 leaves their configured default gateway unreachable despite an FHRP group. Which postchange check most directly establishes the specific problem is resolved?
- Client ARP still resolves R1’s physical IP/MAC as its default, and the client fails when R1 is shut down.
- A client’s gateway ARP resolves the configured VIP to the proper HSRP virtual MAC, and the client retains connectivity after R1 is removed.
- `show standby brief` shows R2 Standby while clients remain configured for R1’s physical IP.
- A web DNS resolution succeeds while no client gateway address or ARP entry is inspected.
Explanation
Correct Answer
B:Correct FHRP protection requires hosts to use the virtual address/MAC that the new Active can own. Checking actual host ARP and failover traffic is stronger than seeing an HSRP group name alone.
Incorrect Answers
A:HSRP relies on hosts using the group virtual default gateway, not one member router’s physical interface IP. Continued dependence on R1’s physical IP or MAC means loss of R1 can still disconnect clients despite a standby member taking over.
C:A healthy standby role cannot save hosts that bypass the VIP.
D:DNS success does not establish correct FHRP virtual first-hop use.
Question 449
The earlier fault was recorded as follows: Both routers show Active for the same HSRP group after a Layer 2 partition, suggesting split-brain rather than normal standby. After corrective work, which observation provides direct evidence that the affected function now behaves correctly?
- Both peers still claim Active for the same group while their hellos cannot cross the VLAN.
- `show standby brief` on both devices reports exactly one Active and the other Standby for the shared group; HSRP hellos are exchanged across the restored VLAN.
- The physical uplinks show carrier, but the shared VLAN remains pruned and peer states never converge.
- An unrelated OSPF prefix is present in a routing table while HSRP group status remains dual-Active.
Explanation
Correct Answer
B:The earlier split-brain followed Layer 2 partition. Restoring peer advertisement reachability and a consistent Active/Standby view directly demonstrates coordination, rather than merely a working uplink LED.
Incorrect Answers
A:HSRP peers that cannot hear one another’s multicast hellos may each believe they should be Active in the same group. Two simultaneous Active states indicate a split-brain condition, not successful convergence to a single forwarding gateway.
C:Link LEDs do not guarantee HSRP advertisement delivery in the correct VLAN.
D:A dynamic route does not prove first-hop group state has recovered.
Question 450
HSRP group 10 uses R1 priority 120 and R2 priority 100. R1 failed; R2 became Active. R1 is now healthy and configured with `standby 10 preempt` (after any configured preempt delay). What observation verifies that higher-priority failback worked?
- The tracked upstream interface remains down on R1, causing its effective priority to stay below R2.
- `show standby brief` reports R2 as Active indefinitely after R1 has fully recovered and preempt delay has elapsed.
- A single client ping to the virtual gateway works, without identifying which router currently owns the Active role.
- `show standby brief` shows R1 Active and R2 Standby after the recovery/preempt conditions are met, with client reachability sustained.
Explanation
Correct Answer
D:With preempt configured and effective R1 priority above the current Active member, R1 may reclaim Active after its delay/conditions are satisfied. Check both roles explicitly through HSRP status and verify traffic remains operational across the transition.
Incorrect Answers
A:Interface tracking can reduce effective HSRP priority while an upstream fault persists; this would not demonstrate takeover by a recovered higher-priority R1.
B:R2 remaining Active could be legitimate if preemption is off or delayed, but it does not prove the specified higher-priority R1 reclaim behavior once preemption conditions are satisfied.
C:The virtual gateway can respond through either router. Successful ping alone validates some gateway reachability, not a role transition back to the desired preferred Active router.
