CCNA IP Routing Practice Test 18 — 15 Questions

Question 1

An engineer is troubleshooting an OSPFv3 adjacency issue between two routers R1 and R2 connected over a serial link. The link is up/up on both sides, and IPv6 is enabled on the interfaces. However, the 'show ipv6 ospf neighbor' command shows no neighbors. The engineer checks the OSPFv3 configuration. What is the most likely cause of the missing adjacency?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

OSPFv3 authentication is configured on R1 but not on R2.. OSPFv3 uses IPsec for authentication, unlike OSPFv2 which uses plaintext or MD5 authentication. If authentication is configured on one router but not the other, the OSPFv3 Hello packets will be dropped, preventing neighbor adjacency from forming. The 'show ipv6 ospf neighbor' command will show no neighbors because the routers cannot exchange Hello packets successfully.

Answer

The serial interface on R2 is administratively down.

Answer

The IPv6 address on R2 is in a different subnet than R1.

Answer

The OSPFv3 router-id is not configured on R2.

Question 2

A network engineer is troubleshooting an OSPFv3 adjacency issue between two directly connected routers. Both routers are configured for OSPFv3 in area 0 on their GigabitEthernet0/0 interfaces. The engineer checks the OSPFv3 neighbor status on R1 and sees that the neighbor state is stuck in EXSTART. The engineer verifies that both interfaces are up and have IPv6 link-local addresses. What is the most likely cause of this problem?

Accepted Answer

Ensure that the MTU is the same on both sides of the link.. The EXSTART state in OSPF indicates that the routers have formed a bidirectional communication and are negotiating the master/slave relationship and the initial Database Description (DBD) packet exchange. A common cause for getting stuck in EXSTART is an MTU mismatch between the two interfaces, which prevents the DBD packets from being accepted by the neighbor, causing the process to stall.

Answer

Configure a global unicast IPv6 address on the interface.

Answer

Change the router ID to be the same on both routers.

Answer

Change the network type to point-to-point.

Question 3

Which TWO statements correctly describe the configuration and verification of OSPFv3 for IPv6?

Accepted Answer

OSPFv3 uses link-local IPv6 addresses to form neighbor adjacencies.. OSPFv3 for IPv6 uses link-local IPv6 addresses (FE80::/10) to form neighbor adjacencies, not global unicast addresses (so B is incorrect). OSPFv3 does not automatically enable on all IPv6 interfaces; each interface must be explicitly configured under the OSPFv3 process using the 'ipv6 ospf' command (so C is incorrect). The 'show ospfv3 neighbor' command displays the neighbor's Router ID (a 32-bit value), not the IPv6 address of the neighbor's interface (so E is incorrect). Correct options A and D accurately describe OSPFv3 neighbor formation using link-local addresses and the information shown by the 'show ospfv3 neighbor' command, which includes neighbor state, neighbor ID, and interface.

Answer

OSPFv3 uses global unicast IPv6 addresses to form neighbor adjacencies.

Answer

OSPFv3 is automatically enabled on all IPv6-enabled interfaces when the routing process is configured.

Answer

The 'show ospfv3 neighbor' command displays the IPv6 address of the neighbor's interface as the neighbor ID.

Question 4

Which TWO statements about HSRP active/standby election, priority, and preempt are true?

Accepted Answer

The router with the highest priority becomes the active router.. In HSRP, the router with the highest priority (default 100, range 0-255) becomes the active router (A). If priorities are equal, the router with the highest IP address on the subnet wins, not the highest MAC address (B). Preemption is disabled by default; 'standby preempt' must be configured for a higher-priority router to take over (C). The 'show standby' command displays active/standby router roles, priority values, and preemption status, verifying D. The standby router is the one with the second-highest priority, not the lowest (E).

Answer

If priorities are equal, the router with the highest MAC address becomes active.

Answer

Preemption is enabled by default on all HSRP routers.

Answer

The router with the lowest priority becomes the standby router.

Question 5

A network engineer is configuring HSRP on a pair of Cisco routers to provide first-hop redundancy for a subnet. The goal is to ensure that the router with the highest IPv4 address always becomes the active router, and that it automatically reclaims the active role after a failure. The engineer configures priority 100 on both routers. Which additional configuration is required to meet these objectives?

Accepted Answer

Configure the preempt command on both routers.. HSRP uses priority to determine the active router, but without the preempt command, a router with a higher priority will not take over the active role if it comes online after a failure. Since both routers have the same priority (100), the router with the highest IPv4 address will become active initially, but to ensure it automatically reclaims the active role after a failure, preempt must be enabled on both routers. This allows the router with the higher IP address (and equal priority) to preempt the current active router when it recovers.

Answer

Configure priority 150 on one router and priority 50 on the other.

Answer

Configure the standby 1 priority 100 command on both routers.

Answer

Configure the standby 1 priority 100 on one router and standby 1 priority 50 on the other.

Question 6

A network administrator is troubleshooting connectivity from a PC (192.168.1.10/24) to a server at 10.0.0.5/24. The PC's default gateway is 192.168.1.1. Router R1 has a directly connected route to 10.0.0.0/24 via interface GigabitEthernet0/1, which is connected to another VLAN. The server is actually located on the 10.0.0.0/16 network, reachable via a static route through 192.168.1.2. What is the most likely cause of the connectivity issue?

Accepted Answer

The directly connected route to 10.0.0.0/24 is the most specific match but is incorrect for the destination.. The router's routing table contains a directly connected route to 10.0.0.0/24, which is the most specific match (longest prefix) for the destination 10.0.0.5. However, if that directly connected subnet is not actually the network where the server resides (e.g., it points to a different interface or VLAN), traffic will be forwarded incorrectly. The router always prefers the most specific prefix, even if another route (like a summary) is administratively preferred or has a lower metric.

Answer

The route to 10.0.0.0/16 has a lower administrative distance than the directly connected route.

Answer

The route to 10.0.0.0/8 has a higher metric, so it is not used.

Answer

The router does not have a default route, so traffic to 10.0.0.5 is dropped.

Question 7

Which TWO statements correctly describe how a router selects the best path for a destination network when multiple routing table entries exist?

Accepted Answer

Routes with the longest prefix length (most specific) are preferred over routes with a shorter prefix.. Routers select the best path by first applying the longest prefix match rule (most specific subnet mask), so option A is correct. If two routes have the same prefix length, the router then compares administrative distance (AD) and prefers the lower AD; option B is incorrect because it says higher AD is selected. When AD is equal, the router uses metric and chooses the lowest metric, making option C correct. Option D is false because directly connected routes have an AD of 0, not 1, and they are indeed more trustworthy than dynamic routes but not due to AD 1. Option E is wrong because directly connected routes are always preferred over dynamic routes regardless of adaptability.

Answer

If two routes have the same prefix length, the route with the higher administrative distance is selected.

Answer

A directly connected route has an administrative distance of 1, making it more trustworthy than any dynamic route.

Answer

Dynamic routes are always preferred over directly connected routes because they can adapt to network changes.

Question 8

Which TWO statements about interpreting routing table output are true? (Choose two.)

Accepted Answer

A route with a longer prefix length is always preferred over a route with a shorter prefix length, regardless of administrative distance.. Longest-prefix match always wins regardless of AD or route source (A correct), and directly connected routes have AD 0 (B correct). C is incorrect because among equal prefix lengths, lower AD wins. D is wrong because metric only compares same-protocol routes, while AD compares across protocols. E fails because a higher AD (200) is less preferred than OSPF's 110.

Answer

If two routes have the same prefix length, the route with the higher administrative distance is preferred.

Answer

The metric is used to compare routes from different routing protocols.

Answer

A static route configured with an administrative distance of 200 will be preferred over an OSPF route with AD 110 for the same network.

Question 9

Drag and drop the following steps into the correct order to configure IPv4 and IPv6 static routes, a default route, and a floating static route with a higher administrative distance, then verify with show ip route and show ipv6 route.

Accepted Answer

1. Enter global configuration mode. 2. Configure IPv4 static routes. 3. Configure IPv6 static routes. 4. Configure default route and floating static route with higher AD. 5. Verify with show ip route and show ipv6 route.. The correct order for configuring static routes as described is: first enter global configuration mode, then configure IPv4 static routes, then IPv6 static routes, then the default route and floating static route with higher AD, and finally verify with show commands. This sequence ensures that specific routes are configured before the default route and that IPv4 routes precede IPv6 routes as implied by the stem. Only option A follows this order; options B, C, and D deviate by placing the default/floating route before specific routes or configuring IPv6 before IPv4.

Answer

1. Enter global configuration mode. 2. Configure default route and floating static route with higher AD. 3. Configure IPv4 static routes. 4. Configure IPv6 static routes. 5. Verify with show ip route and show ipv6 route.

Answer

1. Enter global configuration mode. 2. Configure IPv6 static routes. 3. Configure IPv4 static routes. 4. Configure default route and floating static route with higher AD. 5. Verify with show ip route and show ipv6 route.

Answer

1. Enter global configuration mode. 2. Configure default route and floating static route with higher AD. 3. Configure IPv6 static routes. 4. Configure IPv4 static routes. 5. Verify with show ip route and show ipv6 route.

Question 10

Drag and drop the following steps into the correct order to configure IPv4 and IPv6 static routes, a default route, and a floating static route with higher administrative distance, then verify the routing tables.

Accepted Answer

Configure specific IPv4 and IPv6 static routes, then configure the default route and floating static route with higher AD, then verify routing tables.. The correct order is to first configure specific IPv4 and IPv6 static routes, then configure the default route and the floating static route with higher administrative distance (the order between these two can be interchanged but typically default is configured before the floating static), and finally verify the routing tables with show ip route and show ipv6 route. Option A correctly follows this sequence. Options B, C, and D are incorrect because they either place verification before configuration, configure the default route before specific routes, or configure the floating static route first.

Answer

Configure the default route first, then specific static routes, then the floating static route, then verify routing tables.

Answer

Configure the floating static route first, then specific static routes, then the default route, then verify routing tables.

Answer

Verify routing tables first, then configure specific static routes, then the default route, then the floating static route.

Question 11

Which TWO statements about IPv4/IPv6 static routing are true?

Accepted Answer

An IPv6 default static route can be configured using the destination prefix ::/0.. The IPv6 default static route uses the destination prefix ::/0, which matches all IPv6 addresses, similar to 0.0.0.0/0 in IPv4. Option D is correct because a floating static route is configured with a higher administrative distance and only becomes active when the primary route (with a lower AD) is removed or fails. Option A is wrong: a floating static route is configured with a higher administrative distance, not lower. Option C is wrong: a directly connected route has an administrative distance of 0, which is always preferred over a static route (even with AD 1). Option E is wrong: IPv4 static routes use the 'ip route' command, while IPv6 static routes use the 'ipv6 route' command; the syntax is different.

Answer

A floating static route is configured with a lower administrative distance than the primary route.

Answer

A static route with an administrative distance of 1 is preferred over a directly connected route.

Answer

IPv4 and IPv6 static routes are configured using the same command syntax.

Question 12

Drag and drop the route types on the left to the correct administrative distance and use case descriptions on the right.

Accepted Answer

Connected routes: AD 0, directly connected networks. All the given pairings are correct. Connected routes use AD 0 because they are directly connected. Static routes use AD 1 as they are manually configured. EIGRP internal routes have AD 90, and OSPF routes have AD 110; both are IGPs used for routing within the same autonomous system.

Question 13

Drag and drop the following steps into the correct order to configure a single-area OSPFv2 network on two Cisco routers (R1 and R2) and observe the neighbor state transitions from Down to Full.

Accepted Answer

Configure OSPF process and router-id on R1, then add the network; repeat on R2; ensure interfaces are up; finally verify neighbor states.. First configure OSPF process and router-id on R1, then add the network; repeat on R2; ensure interfaces are up; finally verify neighbor states to see the full transition sequence.

Answer

Configure OSPF process and router-id on R1, then ensure interfaces are up; repeat on R2; add the network; finally verify neighbor states.

Answer

Ensure interfaces are up on both routers, then configure OSPF process and router-id on R1; add the network; repeat on R2; finally verify neighbor states.

Answer

Configure OSPF process and router-id on R1, then add the network; ensure interfaces are up; repeat on R2; finally verify neighbor states.

Question 14

Drag and drop the following OSPFv2 neighbor state transitions into the correct order, starting from the initial Down state on a broadcast or point-to-point network (non-NBMA).

Accepted Answer

Down, Init, 2-Way, ExStart, Exchange. The standard OSPF neighbor state machine on broadcast and point-to-point networks proceeds: Down, Init, 2-Way, ExStart, Exchange, Loading, Full. The Attempt state exists only on NBMA networks and is not used here. Option D correctly lists the first five states in order: Down → Init → 2-Way → ExStart → Exchange. Other options incorrectly include the NBMA-only Attempt state or misorder the states like Loading before Exchange.

Answer

Down, Attempt, Init, 2-Way, ExStart

Answer

Down, Init, 2-Way, ExStart, Loading

Answer

Down, Init, Attempt, 2-Way, ExStart

Question 15

Drag and drop the following OSPFv2 neighbor state transitions into the correct order, starting from the initial state when no neighbor information has been received.

Accepted Answer

Down, Init, 2-Way, ExStart, Exchange. OSPF neighbor states begin at Down, then Init after receiving Hello, 2-Way after seeing own router ID, ExStart for master/slave negotiation, and Exchange for exchanging database descriptors.

Answer

Down, 2-Way, Init, ExStart, Exchange

Answer

Down, Init, ExStart, 2-Way, Exchange

Answer

Down, Init, 2-Way, Exchange, ExStart