CCNA Routing Questions

The decrement value of 10 does not cause R1's priority to drop below R2's default priority of 100 (assuming R1 starts at 100, it becomes 90, still above R2's 100? Actually 90 < 100, but without preempt on R2, R2 won't become active. The main error is missing preempt on R2 and insufficient decrement to ensure R2 takes over.

Missing preempt on R2 prevents R1 from becoming active again after a failure, which violates the requirement that R1 should be active when its interface is up.

The virtual IP is not corrected to 192.168.10.1; it stays at 192.168.10.254, which is not the correct gateway address for the subnet.

A lower AD would make the static route preferred over the dynamic route, not floating.

AD values are integers; 0 is directly connected, and 1 is static. A floating static route must be >1 to be less preferred than a static default.

AD is a static value set at configuration time; it does not auto-adjust.

The specific factual error is that timer mismatches affect the neighbor discovery phase, not the database exchange phase.

The specific factual error is that network type affects the election of DR/BDR and adjacency formation, but not the DBD exchange process.

The specific factual error is that area ID mismatches cause OSPF to ignore hello packets, so the adjacency never progresses beyond DOWN.

The problem is not due to missing global addresses; the adjacency is stuck at EXSTART, not at DOWN or INIT.

The show output shows different router IDs (192.168.1.1 and 192.168.1.2), so this is not the issue.

The adjacency is stuck in EXSTART, which is not typically resolved by changing network type; the issue is related to packet exchange.

192.168.40.0/24 is a valid route but less specific than 192.168.40.128/25. Since the destination IP falls within both, the router prefers the more specific /25 route, so this option is incorrect.

0.0.0.0/0 is the default route and only used when no other route matches. Since more specific routes exist for the destination IP, this option is incorrect.

Overlapping routes like /24 and /25 are common and resolved by longest prefix match. The presence of overlapping entries does not prevent route selection, so this option is incorrect.

Mismatched OSPF process IDs do not prevent neighbor formation because process IDs are locally significant identifiers on each router. They do not need to match for adjacency to form, so this option is incorrect.

Missing default routes do not affect OSPF neighbor formation. Default routes influence routing decisions but are not required for establishing OSPF adjacencies, so this option is incorrect.

Different router IDs are necessary for OSPF neighbors to uniquely identify each router. Having different router IDs does not cause adjacency failure, so this option is incorrect.

Incorrect. PPP authentication applies to serial interfaces and point-to-point links, but the exhibit shows a GRE tunnel configuration, not PPP on a serial link.

Incorrect. WPA3 is a wireless security protocol unrelated to GRE tunnels, which operate at Layer 3 and do not configure wireless security settings.

Incorrect. GRE tunnels do not automatically enable BGP or any routing protocol; routing protocols must be explicitly configured over the tunnel interface.

Priority 0 excludes the router from DR/BDR election entirely; it can only become a DROTHER.

A new router with a higher priority does not trigger a new election unless the existing DR or BDR goes down.

DROTHERs do not form full adjacencies among themselves; they only exchange LSAs via the DR/BDR.

Although removing 'passive-interface default' would also restore OSPF on these interfaces, the solution commands show the preferred method of overriding the default selectively, making this option incorrect for the given scenario.

The network statements on R1 already correctly include the /30 subnets, so there is no need to change wildcard masks.

The OSPF network type defaults to broadcast, which is appropriate for Ethernet links; changing to point-to-point does not resolve the passive-interface issue and would not fix hello suppression.

OSPF routes are installed when EIGRP is present; routing protocols coexist and the route with the lowest AD is selected.

OSPF supports both IPv4 and IPv6; it is not limited to IPv6.

EIGRP routes do not always have a smaller subnet mask; prefix length is determined by the network design, not the routing protocol.

A floating static route is configured with a higher administrative distance than the primary route, not lower.

A directly connected route has an administrative distance of 0, which is preferred over a static route with AD 1.

IPv4 static routes use the 'ip route' command, while IPv6 static routes use the 'ipv6 route' command; the syntax is different.

This option is incorrect because PPP (Point-to-Point Protocol) does not require HDLC (High-Level Data Link Control) for authentication; PPP can authenticate independently of the encapsulation method used.

This option is incorrect because CHAP (Challenge Handshake Authentication Protocol) does not require routers to be in different IPv4 subnets for authentication to function. CHAP can authenticate devices regardless of their subnet configuration as long as they can reach each other over the network.

This option is incorrect because PPP (Point-to-Point Protocol) can operate independently of GRE (Generic Routing Encapsulation) tunnels; authentication can occur directly over a PPP link without requiring GRE.

This would break the HSRP relationship entirely, not fix the priority issue.

Preemption is not the cause; it is actually desired to allow a higher-priority router to take over.

This does not address the priority mismatch and could worsen convergence time.

The specific factual error is that 'decrement' is not a valid keyword in the standby track command. The decrement value is specified directly after the interface.

The specific factual error is that 'preempt delay' is not the correct way to configure tracking. Tracking is done with the 'standby track' command, and the decrement value must be specified.

The specific factual error is that 'priority' is not a valid keyword in the standby track command. The decrement value is specified directly after the interface.

172.16.0.0/16 is the least specific route covering a large address range. Although it matches the destination IP, it is overridden by more specific routes with longer subnet masks, so it is not used.

172.16.20.0/24 is more specific than the /16 but less specific than the /25 route. Since the destination IP falls within the /25 subnet, the router prefers the /25 route over this /24.

The default route is only used when no other routes match the destination IP. Since multiple specific routes exist that match the destination, the default route is not selected.

This option is incorrect because the static default route is less specific (0.0.0.0/0) and only used when no other route matches the destination. Since a connected route exists, the default route is ignored.

This option is wrong because routing does not load balance between a directly connected route and a static default route. The router selects the single best route based on prefix length and administrative distance.

This option is incorrect because the router clearly has a matching directly connected route for 10.1.1.200. Therefore, it will use that route rather than discarding both or failing to forward.

PBR must be applied inbound on the interface receiving the traffic, not outbound on the exit interface.

PBR uses the access list to match traffic based on source, destination, or other criteria; here the requirement is to match source subnet.

A static route controls forwarding based on destination, not source. Policy-based routing is needed to forward based on source address.

Candidates mistakenly assume that OSPF process IDs must match globally for proper LSA exchange, but they are only locally significant.

Candidates may think that the network type influences the OSPF LSA type, but it only affects neighbor discovery and DR/BDR election, not the area origin of LSAs.

Candidates sometimes confuse the metric influence with the route type, thinking that OSPF converts routes when the cost exceeds a threshold.

This option is incorrect because OSPF neighbors must be in the same area to form adjacency. Using different areas on the same segment prevents adjacency, so this option contradicts OSPF area rules.

This option is incorrect because OSPF authentication, including message-digest (MD5), is supported on Ethernet interfaces, not just serial links. Authentication is not limited by interface type.

This option is incorrect because OSPF requires valid IP addressing on interfaces to operate. Removing IP addressing disables OSPF on that link, so adjacency cannot form without IP addresses.

Option A suggests changing the destination network mask from /24 to /16. While subnet masks must be correct for proper routing, an incorrect mask does not cause next-hop reachability issues or packet drops due to unreachable next-hop addresses. The problem here is related to next-hop reachability, not the destination mask.

Option C incorrectly states that static routes require an outbound access list. Static routes do not need ACLs to function; ACLs are used for traffic filtering and security policies, not for enabling or disabling static routes. This option is invalid.

Option D claims the route must use administrative distance 255. Administrative distance 255 actually makes a route unusable, so setting it to 255 would prevent the static route from working. The default administrative distance for static routes is 1, which is preferred over most dynamic routes.

This option is incorrect because a VLAN is a Layer 2 segmentation method that isolates broadcast domains and does not relate to routing policies or autonomous systems in BGP.

This option is wrong since an OSPF area is a subdivision within a single routing domain to optimize routing, not an autonomous system representing separate administrative control.

This option is incorrect because an autonomous system is a routing domain concept, whereas a wireless access point is a physical device unrelated to BGP or routing domains.

This option is incorrect because OSPF can still form adjacencies between routers in different areas, provided they are correctly configured to do so. The issue in this scenario is related to OSPF timers, not area mismatches.

This option is incorrect because OSPF can still exchange multicast packets even if the subnet mask is not configured correctly, as long as the interfaces are up and configured for OSPF. The failure to form an adjacency is more likely due to mismatched OSPF timers.

This option is wrong because OSPF process IDs do not need to match for routers to form an adjacency; they only need to be in the same area and have matching network statements.

This option fails to account for the explicit passive interface state shown on R2. A missing network statement would not cause the interface to be displayed as passive; it would simply not be enrolled in the OSPF process.

This is a common misconception, but process ID mismatch does not affect OSPF neighbor formation. The passive interface status on R2 directly contradicts this as the cause.

The passive interface status would not appear if the only issue were interval mismatches; the interface would still be active and sending hellos. This directly conflicts with the given show output.

A distribute-list requires explicit configuration; its absence makes this an unsubstantiated guess.

Area border routers receive all LSAs from non-backbone areas; the area boundary does not stop LSA propagation to the ABR itself.

The null0 route is a loop-prevention mechanism, not an absolute traffic blocker; more-specific entries in the routing table take precedence.

Uses AD 2 instead of the specified AD 200 and a wrong next-hop of 10.2.2.1.

Uses AD 1 (equal to the primary route's AD), preventing failover, and a wrong next-hop of 10.2.2.1.

Uses AD 250 instead of the required AD 200 as specified in the question, and still uses the wrong next-hop.

The virtual IP address is wrong; it should be 192.168.1.1, not 192.168.1.254.

The decrement value is 10 instead of the required 15.

The priority is not increased; it remains at the default 100, so R1 may not become the Active router.

Neighbor adjacency failure due to timer mismatch would have prevented R2 from becoming BDR at all.

High priority increases the chance of being elected DR, not decrease it.

Point-to-point networks do not have DR/BDR elections, so R2 could not have been BDR.

MTU mismatch can cause OSPF adjacency problems during the database exchange phase, but it does not typically prevent the initial neighbor relationship from forming. Since the question states adjacency cannot form, MTU mismatch is unlikely the primary cause.

Missing router IDs do not prevent OSPF adjacency because routers automatically generate a router ID if none is configured. Therefore, this option is not a valid cause for adjacency failure.

A duplicate static route to 10.1.12.0/30 does not affect OSPF neighbor formation, as static routes are unrelated to OSPF adjacency processes. This option is irrelevant to the adjacency issue.

Incorrect because static routes can reference exit interfaces directly; Cisco routers support static routes with either next-hop IP addresses or exit interfaces.

Incorrect because the subnet mask length (such as /16 vs /24) does not prevent a static route from being installed; the issue is the interface state, not the mask.

Incorrect because static routes do not depend on NTP or time synchronization for installation; this is unrelated to static routing behavior.

This is a common misconception; OSPFv3 uses the router ID for neighbor identification, not the process ID.

Link-local addresses are automatically configured and do not affect OSPFv3 adjacency as long as they are unique.

In this scenario, no neighbors are seen, indicating a more fundamental issue like OSPFv3 not being enabled on the interface.

Option C is incorrect because administrative distance is not compared before prefix length; prefix length is the primary factor in route selection, making this option a common misconception.

Option D is incorrect because Cisco routers do not load-balance between a default route and a more specific route; these routes are not considered equal-cost and the more specific route is always preferred.

A lower AD indicates a more trustworthy source, so the route with the lower AD is preferred, not the higher one.

Metrics are only comparable within the same routing protocol (e.g., OSPF cost vs. EIGRP composite metric). For different protocols, AD is used to select the best route.

A lower AD is preferred; OSPF AD 110 is lower than 200, so the OSPF route would be chosen.

The specific factual error is that the passive-interface command is applied on the wrong router (R2 instead of R1) and the timers are changed on R1 instead of R2.

The specific factual error is that the timer change is applied to the wrong interface (R1's G0/0 already has correct timers) and the passive-interface is applied to the wrong router.

The specific factual error is that the timer values are not changed; they remain mismatched with R1's timers.