CCNA IP Routing Practice Test 23 — 15 Questions

Question 1

Two directly connected routers, R1 and R2, are configured with single-area OSPF in Area 0. The administrator notices that they are not forming a full OSPF neighbor adjacency. The exhibit displays relevant portions of the running configurations. What is the most likely cause of the problem?

Accepted Answer

R1's passive-interface default prevents OSPF hello packets from being sent on GigabitEthernet0/0.. The passive-interface default command on R1 sets all interfaces to passive by default, which prevents OSPF hello packets from being sent out GigabitEthernet0/0. Without hello packets, R1 cannot discover R2 or form a neighbor adjacency, even though the network command is correctly configured. This is the most likely cause because the exhibit shows R1's configuration includes passive-interface default without a corresponding no passive-interface GigabitEthernet0/0 statement.

Answer

The network command on R1 does not include the correct subnet mask.

Answer

The GigabitEthernet0/0 interface on R2 is administratively down.

Answer

The routers are configured with different OSPF area IDs.

Question 2

A network engineer configures a primary default route via Gi0/0 (next-hop 192.168.12.2) and a floating static default route via Gi0/1 (next-hop 192.168.12.6) with AD 200. To test failover, the engineer issues the shutdown command on Gi0/0. After this, the router does not have a default route in the routing table. Which problem explains this behavior?

Accepted Answer

The backup interface Gi0/1 is administratively down, making the next-hop unreachable.. A floating static route is installed only if its next-hop is reachable and the primary route (with lower AD) is absent. Shutting down Gi0/0 removes the primary route. However, backup interface Gi0/1 is also administratively down, so the next-hop 192.168.12.6 is unreachable, and the floating route is not installed. Option A correctly identifies the interface status as the root cause. Option B is wrong because a higher AD (200) correctly designates this as a backup; a lower AD would make it primary. Option C is false; shutting down an interface removes connected routes, which causes the recursive static route to be purged. Option D is incorrect because floating static routes do not require a track object—the AD difference alone dictates failover when the primary is removed.

Answer

The floating static route uses an administrative distance of 200, which is too low to replace the primary route.

Answer

The primary default route remains in the routing table because shutting down Gi0/0 does not remove the static route.

Answer

The floating static route is missing a track object, so the router cannot detect the primary path failure.

Question 3

Two routers, R1 and R2, have been configured with HSRP for VLAN 10 to provide default gateway redundancy to hosts. The virtual IP address is 192.168.10.1. After configuration, end hosts report inconsistent connectivity to the gateway, and a failover test reveals that when the active router is shut down, connectivity is lost. The network administrator checks the HSRP status on both routers. Based on the output shown, what is the most likely cause of the redundancy failure?

Accepted Answer

The HSRP group number is mismatched between R1 and R2.. HSRP uses the group number to identify the virtual router instance. If the group numbers on R1 and R2 do not match, they will not form a neighbor relationship or exchange HSRP messages, so neither router will know the other exists. This prevents failover: when the active router goes down, the standby router does not take over because it never learned about the active router's state. The output would show that each router believes it is the active router (or that no standby exists), confirming the mismatch.

Answer

R2 has a lower HSRP priority than R1, so it cannot become standby.

Answer

The HSRP authentication strings do not match.

Answer

HSRP version 1 is used on R1 while version 2 is used on R2.

Question 4

A network administrator configures OSPF on two routers, R1 and R2, connected via their Serial0/0/0 interfaces (IP addresses 10.1.1.1/30 and 10.1.1.2/30). They verify that both routers use the same OSPF process ID and area 0, but R1's 'show ip ospf neighbor' shows no adjacencies. Given the partial exhibit from R1, what is the most likely cause of the adjacency failure and its correct solution?

Accepted Answer

Configure 'no passive-interface Serial0/0/0' under router ospf 1 on R1.. The most likely cause is that R1's Serial0/0/0 interface is configured as a passive interface under OSPF. When an interface is set as passive, OSPF does not send Hello packets out of it, preventing neighbor discovery and adjacency formation. The solution is to use the 'no passive-interface Serial0/0/0' command under router ospf 1 on R1, which allows Hello packets to be transmitted and the adjacency to establish.

Answer

Replace the network statement with 'network 10.1.1.0 0.0.0.255 area 0' to cover a larger range.

Answer

Change the OSPF process ID on R1 to match R2, using 'router ospf 100' and re-entering the network command.

Answer

Issue 'clear ip ospf process' on R1 to restart OSPF and reattempt neighbor discovery.

Question 5

An administrator configured a floating static default route on R1 as a backup to reach 10.10.10.0/24. The primary path is learned via OSPF, and the floating static route uses an administrative distance of 130. After the primary OSPF neighbor fails, traffic to 10.10.10.0/24 is dropped. According to the exhibit, why is the backup default route not being used?

Accepted Answer

The static route specifies an outgoing interface that is down; the next‑hop must be reachable for the route to be used.. The floating static default route is not used because the outgoing interface specified in the static route is down. For a static route with an outgoing interface to be considered valid and installed in the routing table, the interface must be in an up/up state. When the primary OSPF neighbor fails, the backup static route cannot be used because its next-hop is unreachable due to the interface being down, causing traffic to be dropped.

Answer

The administrative distance of 130 is still less than the OSPF default of 110, so it will never be installed.

Answer

The static route is missing the permanent keyword, which is required for backup routes.

Answer

The metric of the static route is too high; it should be reduced to 0.

Question 6

Drag and drop the following steps into the correct order to configure and verify OSPFv3 neighbor adjacency using link-local addresses in area 0.

Accepted Answer

Enable IPv6 unicast routing with the 'ipv6 unicast-routing' global command.. The correct order enables IPv6 unicast routing globally, creates the OSPFv3 process, enters interface configuration, assigns the interface to the OSPFv3 process in area 0 (which activates OSPFv3 on the link), and finally verifies the neighbor relationship. IPv6 unicast routing must be enabled first because OSPFv3 requires IPv6 packet forwarding. The router process must exist before an interface can be associated with it. Assigning the interface to area 0 triggers Hello packet exchange over link-local addresses. The show command confirms the adjacency formed.

Question 7

Drag and drop the following steps into the correct order to configure and verify HSRP with priority and preemption on an interface.

Accepted Answer

Enter interface configuration mode for the target interface (e.g., interface GigabitEthernet0/0).. First, enter interface configuration mode to start configuring the specific interface. Next, assign an IP address because HSRP requires a real IP on the interface for communication between HSRP routers. After that, define the HSRP group and virtual IP, which clients use as their default gateway. Then set a higher priority to influence the active router election; priority must be configured before enabling preemption, as preemption relies on priority to determine when to take over. Finally, exit configuration mode and verify with show standby to confirm the HSRP state.

Question 8

Drag and drop the following steps into the correct order to determine the best route to a destination using a routing table.

Accepted Answer

Extract the destination IP address from the packet.. The correct order follows Cisco's route selection logic: 1. Extract the destination IP (the lookup key). 2. Find all matching routes in the routing table. 3. Apply longest prefix match – the most specific route (longest subnet mask) is always preferred, regardless of administrative distance. 4. If multiple routes share that longest prefix length, compare administrative distances. 5. The route with the lowest administrative distance wins. 6. If AD values are equal (same routing protocol is typical), compare metrics. 7. The route with the lowest metric becomes the best route. This hierarchy – longest match > AD > metric – is fundamental to Cisco router behavior.

Question 9

Drag and drop the following steps into the correct order to configure an IPv4 default static route with a floating backup route on a Cisco router.

Accepted Answer

Enter privileged EXEC mode using the enable command.. The correct order is: 1. Enter privileged EXEC mode using the enable command, because you must be in privileged mode to enter global configuration. 2. Enter global configuration mode with configure terminal, as static routes are configured in global configuration. 3. Configure the primary default route using ip route 0.0.0.0 0.0.0.0 with default administrative distance (1), establishing the primary path. 4. Configure the floating backup route using ip route 0.0.0.0 0.0.0.0

(e.g., 10), so it is less preferred. 5. Exit global configuration mode using end to return to privileged EXEC. 6. Save the configuration with copy running-config startup-config to ensure the routes persist after a reboot.

Question 10

Drag and drop the following steps into the correct order to configure single‑area OSPFv2 on a router, advertise the 192.168.10.0/24 and 10.0.0.0/24 networks in area 0, and set the GigabitEthernet0/0 interface as passive.

Accepted Answer

Enter global configuration mode using the 'configure terminal' command.. The correct sequence is: (1) Enter global configuration mode with 'configure terminal' – this is required before any configuration commands. (2) Initiate the OSPF process with 'router ospf 1' – this places the CLI into OSPF router configuration mode where the remaining commands are issued. (3) Advertise the 192.168.10.0/24 network in area 0 – the 'network' command must be issued under OSPF router mode to inject the connected network into OSPF. (4) Advertise the 10.0.0.0/24 network – a second 'network' statement; the order of network commands is interchangeable but they must be configured before setting passive interfaces in a logical workflow. (5) Configure GigabitEthernet0/0 as a passive interface – this prevents OSPF Hello packets and neighbor adjacency on that interface while still advertising its subnet, and it is configured under OSPF router mode. (6) Return to privileged EXEC mode with 'end' – exits configuration mode and returns to the enable prompt. While setting a passive interface before the network statement does not break the configuration, Cisco documentation suggests adding networks first to clearly define which interfaces participate in OSPF before applying passive-interface restrictions.

Question 11

Drag and drop the following steps into the correct order to configure and verify HSRP on a router interface.

Accepted Answer

Enter interface configuration mode for the target interface.. The correct order begins by entering interface configuration mode, because all HSRP commands are applied at the interface level. Next, assign a physical IPv4 address to the interface, as HSRP requires a Layer 3 interface with an IP address to function. Set HSRP version 2 before defining the HSRP group to ensure compatibility with extended group numbers and newer features. Then configure the HSRP group number and virtual IP address to create the standby group. After that, set the router’s priority and enable preemption; these steps customize the active/standby election process. Finally, verify the configuration with the show standby command to confirm HSRP operation.

Question 12

Drag and drop the following steps into the correct order to configure OSPFv3 for IPv6 on a Cisco router and verify basic neighbor relationships.

Accepted Answer

Enable IPv6 routing globally with the 'ipv6 unicast-routing' command.. IPv6 unicast routing must be enabled first, as OSPFv3 relies on the router being IPv6 aware. Next, the OSPFv3 process is created globally. The interface must then be IPv6-enabled to auto-generate the link-local address used by OSPFv3 for forming adjacencies. After that, the interface is added to OSPFv3 Area 0. Finally, the 'show ospfv3 neighbor' command is used to verify that an adjacency has formed.

Question 13

Drag and drop the following steps into the correct order to configure and verify a floating IPv4 static route as a backup path.

Accepted Answer

Configure the primary static route to the destination network using the primary next-hop address, leaving the administrative distance at its default value (1).. The correct order begins with configuring the primary static route because it defines the main path. Checking its administrative distance (default 1) is essential to then set a higher AD for the floating route, ensuring it acts only as a backup. Next, the floating static route is configured with a higher AD so it is less preferred. Verification of the routing table shows only the primary route installed. Simulating a failure by shutting down the primary interface triggers the failover. Finally, rechecking the routing table confirms the floating route is now active, proving backup operation.

Question 14

Which TWO statements about IPv4 and IPv6 static routes, including floating static routes, are correct?

Accepted Answer

A floating static route uses a higher administrative distance than the primary route to provide backup connectivity.. Option A is correct because a floating static route is configured with a higher administrative distance (AD) than the primary route. This ensures the floating route is only used when the primary route fails, as the router prefers routes with lower AD values. For example, if the primary route has an AD of 1 (static route default), the floating static route might be set to AD 200, making it a backup.

Answer

In IPv6, the default route prefix is 0.0.0.0/0.

Answer

For a floating static route to be installed in the routing table, it must have an administrative distance lower than that of the primary route.

Answer

An IPv4 static route will only be inserted into the routing table if its next-hop IP address belongs to a directly connected subnet.

Question 15

Which TWO statements are true about OSPFv2 neighbor adjacency, network statements, and passive interfaces?

Accepted Answer

Configuring an interface as passive stops OSPF from sending Hello packets out of that interface, but OSPF will still advertise the connected network in its LSAs.. Option A is correct because configuring an interface as passive in OSPFv2 prevents the router from sending Hello packets out of that interface, which stops neighbor discovery and adjacency formation. However, OSPF still includes the connected network of that passive interface in its Type 1 Router LSAs, allowing the network to be advertised to other OSPF routers.

Answer

The network command with a wildcard mask of 0.0.0.0 will enable OSPF on the exact matching interface, but it will also prevent OSPF from forming adjacencies on that interface.

Answer

Using the passive-interface default command makes all OSPF interfaces passive, which means OSPF will not advertise any connected networks.

Answer

The network command with a wildcard mask of 0.0.0.255 area 0 will match any interface whose IP address falls within that /24 subnet, but OSPF will only attempt to form adjacencies on the interface with the highest IP address in that range.

CCNA IP Routing Practice Test 23 — 15 Questions

Exhibit

CCNA IP Routing Practice Test 23 — 15 Questions

Exhibit