CCNA IP Routing Practice Test 22 — 15 Questions

Question 1

You are connected to R1 via console. R1 is connected to R2 via GigabitEthernet0/0 and to R3 via GigabitEthernet0/1. OSPF has been configured, but R1 is not forming a full adjacency with R2. You run `show ip ospf neighbor` on R1 and see R2 stuck in EXSTART state. You also run `show ip ospf interface GigabitEthernet0/0` and see the network type is broadcast. You need to identify and resolve the issue.

Accepted Answer

Change the OSPF network type on R1's GigabitEthernet0/0 interface to point-to-point.. R1's Gi0/0 defaults to OSPF broadcast network type, while R2 is likely configured as point-to-point. This mismatch prevents the routers from forming a full adjacency, often leaving them stuck in EXSTART or 2-WAY state. Changing R1's interface to point-to-point aligns the network types, allowing adjacency to form. The other options are incorrect because hello interval mismatches (B) or DR priority (C) are not the root cause, and adding the broadcast command (D) would not fix a point-to-point mismatch.

Answer

Increase the OSPF hello interval on R1's GigabitEthernet0/0 interface to match R2's hello interval.

Answer

Configure the OSPF priority on R1's GigabitEthernet0/0 interface to 0 to prevent it from becoming the DR.

Answer

Add the 'ip ospf network broadcast' command on R1's GigabitEthernet0/0 interface.

Question 2

You are connected to R1 via console. R1 has two paths to the Internet: primary via ISP1 (G0/0) and backup via ISP2 (G0/1). The primary route has an administrative distance of 1, and the backup should only be used if the primary fails. Currently, both routes are active. You need to configure a floating static route for the backup.

Accepted Answer

ip route 0.0.0.0 0.0.0.0 G0/1 200. A floating static route with a higher administrative distance (200) than the primary route (1) ensures it is only used when the primary route is removed from the routing table, providing redundancy.

Answer

ip route 0.0.0.0 0.0.0.0 G0/1 1

Answer

ip route 0.0.0.0 0.0.0.0 G0/1 0

Answer

ip route 0.0.0.0 0.0.0.0 G0/1 255

Question 3

You are connected to R1 via console. R1 and R2 are connected via a serial link. OSPFv2 has been configured, but the adjacency is stuck in EXSTART state. You suspect a mismatched MTU. On R1, the interface MTU is currently set to 1400, while R2 uses the default MTU of 1500. You need to verify and fix the issue.

Accepted Answer

On R1, configure the interface MTU to 1500 and then clear the OSPF process using 'clear ip ospf process'.. OSPF requires matching MTU values on a link. The incorrect MTU on R1 (1400) caused the adjacency to stall in EXSTART. Setting MTU to 1500 and clearing the OSPF process allows proper adjacency formation.

Answer

On R1, configure the interface MTU to 1500 and then reload the router to apply the change.

Answer

On R1, configure the interface MTU to 1500 and then change the OSPF network type to point-to-point.

Answer

On R1, configure the interface MTU to 1500 and then adjust the OSPF hello and dead timers to match R2.

Question 4

You are connected to R1 via the console. R1 is a new router that connects to three subnets: 192.168.1.0/24 (connected to GigabitEthernet0/0), 192.168.2.0/24 (connected to GigabitEthernet0/1), and 192.168.3.0/24 (connected to GigabitEthernet0/2). R1 must be able to ping the loopback0 interface of R2 (192.168.100.1/32) which is reachable via R2's Serial0/0/0 interface (10.0.0.2/30). The link between R1 and R2 is 10.0.0.0/30, with R1's interface being 10.0.0.1/30. No dynamic routing protocols are configured. Configure R1 to reach the loopback address of R2 using a host-specific static route (not a default route).

Accepted Answer

ip route 192.168.100.1 255.255.255.255 10.0.0.2. Option A is correct because it configures a host route (mask /32) to destination 192.168.100.1 with next-hop 10.0.0.2, directly matching the loopback address and providing exact reachability. Option B is incorrect because it uses a /24 mask, which does not match the /32 loopback and would cause routing issues. Option C is incorrect because it uses next-hop 192.168.1.1, which is not the directly connected neighbor; packets would be forwarded to a local interface, not across the serial link. Option D is incorrect because it creates a default route (0.0.0.0/0) rather than the required host-specific route, failing to meet the specific task requirement.

Answer

ip route 192.168.100.0 255.255.255.0 10.0.0.2

Answer

ip route 192.168.100.1 255.255.255.255 192.168.1.1

Answer

ip route 0.0.0.0 0.0.0.0 10.0.0.2

Question 5

You are connected to R1 via the console. R1 and R2 are configured with EIGRP AS 100. R1 has two paths to the 172.16.1.0/24 network: one via a FastEthernet link to R2 (bandwidth 100 Mbps, delay 100 microseconds) and another via a serial link to R2 (bandwidth 1.544 Mbps, delay 20000 microseconds). The EIGRP metric is calculated using the default K-values. The FastEthernet link is preferred, but you need to make the serial link the backup by adjusting the administrative distance.

Accepted Answer

Configure a static route to 172.16.1.0/24 with next-hop 10.0.0.6 and administrative distance 170.. A floating static route is configured with an administrative distance of 170, which is higher than EIGRP's default distance of 90. This ensures that the static route is only used when the EIGRP route is not available. The static route points to the next-hop IP address of R2's serial interface.

Answer

Configure a static route to 172.16.1.0/24 with next-hop 10.0.0.6 and administrative distance 90.

Answer

Configure a static route to 172.16.1.0/24 with next-hop 10.0.0.6 and administrative distance 1.

Answer

Configure a static route to 172.16.1.0/24 with next-hop 10.0.0.6 and administrative distance 255.

Question 6

You are connected to R1 via the console. R1 and R2 are running OSPFv2 in area 0. R1's router ID is 1.1.1.1, and R2's router ID is 2.2.2.2. Both routers are connected via GigabitEthernet0/0 on the 192.168.12.0/30 subnet. You need to ensure that R1 does not send OSPF hello messages out of its Loopback0 interface, while still advertising the loopback network into OSPF.

Accepted Answer

Configure the passive-interface Loopback0 command under the OSPF process.. Configuring the Loopback0 interface as passive under the OSPF process suppresses the sending of hello messages on that interface, preventing unnecessary adjacencies. The network is still advertised because OSPF includes the subnet in its LSAs.

Answer

Remove the network 192.168.12.0 0.0.0.3 area 0 command from the OSPF configuration.

Answer

Configure the ip ospf passive-interface command on GigabitEthernet0/0.

Answer

Configure the network 192.168.12.0 0.0.0.3 area 0 command under the OSPF process.

Question 7

Which three options accurately describe characteristics of OSPFv2 in a single area? (Choose three.)

Accepted Answer

OSPF uses cost as its metric, which is derived from the bandwidth of the interface.. OSPFv2 uses cost as its metric, derived from interface bandwidth using the formula cost = reference bandwidth / interface bandwidth (default reference bandwidth is 100 Mbps). Hello packets are used to discover neighbors, maintain adjacencies, and act as keepalives (default every 10 seconds on broadcast networks). The designated router (DR) is elected only on broadcast multiaccess networks (e.g., Ethernet) to reduce LSA flooding. The incorrect options: OSPFv2 does not natively support IPv6 (OSPFv3 is needed for IPv6); LSAs are refreshed every 30 minutes, not 30 seconds; router IDs must be unique across the OSPF domain, not the same in an area.

Answer

OSPFv2 supports IPv6 routing natively without any additional configuration.

Answer

Link-state advertisements (LSAs) are sent periodically every 30 seconds by default.

Answer

OSPF routers in the same area must be configured with the same router ID.

Question 8

Which three statements about the routing table and route selection are correct? (Choose three.)

Accepted Answer

The route with the longest prefix match is always preferred when multiple routes match the destination IP.. The route with the longest prefix match is always preferred because it is the most specific route to the destination IP. A directly connected route has an administrative distance of 0 by default, making it the most trusted route source. If two routes have the same prefix length, administrative distance, and metric, equal-cost load balancing can occur, distributing traffic over multiple paths.

Answer

The administrative distance of a static route is always 1.

Answer

An OSPF inter-area route has a lower administrative distance than an OSPF intra-area route.

Answer

A default route (0.0.0.0/0) is always preferred over any more specific route.

Question 9

Which three of the following are valid features of Enhanced Interior Gateway Routing Protocol (EIGRP)? (Choose three.)

Accepted Answer

EIGRP maintains a topology table containing all routes learned from neighbors.. All three statements are correct features of EIGRP. EIGRP maintains a topology table that stores all routes learned from directly connected neighbors, including feasible successors. It uses the Diffusing Update Algorithm (DUAL) to guarantee loop-free paths by performing a diffusing computation when a route is lost. Additionally, EIGRP supports unequal-cost load balancing by using the 'variance' command, which allows traffic to be distributed across multiple paths with different metrics, as long as the metric of the alternate path is within the variance multiplier times the best metric.

Answer

EIGRP is a link-state routing protocol similar to OSPF.

Answer

EIGRP uses multicast address 224.0.0.5 for all neighbor communications.

Answer

EIGRP automatically summarizes routes at classful boundaries by default on all interfaces.

Question 10

Which three statements about IPv6 routing are correct? (Choose three.)

Accepted Answer

IPv6 static routes can be configured using the 'ipv6 route' command.. All three statements are correct. The 'ipv6 route' command is used to configure static routes in IPv6, similar to 'ip route' in IPv4. A directly attached IPv6 static route can indeed use a link-local address as the next hop, which is common for point-to-point interfaces. OSPFv3 (OSPF for IPv6) uses the same fundamental SPF algorithm and link-state concepts as OSPFv2 but is designed to support IPv6 addressing and runs per-link rather than per-subnet.

Answer

EIGRP for IPv6 uses the same autonomous system number as EIGRP for IPv4 and shares the same routing table.

Answer

IPv6 routing is enabled by default on all Cisco routers.

Answer

The default route in IPv6 is represented as ::/128.

Question 11

Which three of the following are true regarding the forwarding decision process in a router? (Choose three.)

Accepted Answer

The router performs a recursive route lookup if the next-hop address in a static route is not directly connected.. A router performs a recursive route lookup when the next-hop address in a static route is not directly connected, meaning the router must find a route to that next-hop address before forwarding. The Forwarding Information Base (FIB) is used in Cisco Express Forwarding (CEF) mode to provide fast, hardware-based packet switching by pre-populating the forwarding table from the routing table. When a packet arrives, the router first checks the routing table (RIB) for the best matching route, which is the longest prefix match, to determine the next-hop and outgoing interface.

Answer

The router always performs an ARP request for every destination IP address in a packet.

Answer

If the destination IP is on the same subnet as an interface, the router forwards the packet directly without checking the routing table.

Answer

The router rewrites the source MAC address to the MAC address of the next-hop router for every forwarded packet.

Question 12

Which four of the following statements about IPv4 static routing are true? (Choose all that apply. There are four correct answers.)

Accepted Answer

A default static route uses 0.0.0.0/0 as the destination network.. A default static route with destination 0.0.0.0/0 matches all packets when no more specific route exists, acting as a gateway of last resort. A floating static route uses a higher administrative distance (e.g., 150) than the dynamic protocol's default (e.g., 110 for OSPF), so it only appears in the routing table if the dynamic route fails. A fully specified static route includes both the exit interface and next-hop IP, eliminating recursive lookups. A recursive static route specifies only the next-hop IP, forcing the router to perform multiple routing table lookups to find the exit interface.

Answer

A static route pointing to a next-hop IP address only is resolved through ARP on the router.

Answer

An IPv4 static route can use an IPv6 address as the next hop.

Question 13

Which three of the following statements about distance vector routing protocols (e.g., RIP, EIGRP) are correct? (Choose all that apply. There are three correct answers.)

Accepted Answer

They rely on the Bellman-Ford algorithm for route computation.. RIPv2 sends updates to the multicast address 224.0.0.9, ensuring only RIPv2 routers process them. EIGRP maintains both feasible distance (best metric to a destination) and advertised distance (metric reported by the next-hop router) to support its loop-free DUAL algorithm. Split horizon prevents routing loops by not advertising a route back out the interface from which it was learned. The statement about reliance on Bellman‑Ford is false because EIGRP uses DUAL, not Bellman‑Ford; the other two wrong options confuse distance vector behavior with link-state (full topology map) or assume unequal-cost load balancing is default when it requires the variance command.

Answer

They require a full topological map of the network to calculate the best path.

Answer

EIGRP supports both equal-cost and unequal-cost load balancing by default.

Question 14

Which three of the following are characteristics of a distance-vector routing protocol? (Choose three.)

Accepted Answer

Routers send their entire routing table to directly connected neighbors at regular intervals.. Distance-vector routing protocols are characterized by periodic full routing table updates to directly connected neighbors, as seen in classic protocols like RIP. However, advanced distance-vector protocols such as EIGRP do not send their full routing table at regular intervals; they perform a one-time full exchange during neighbor formation and then send only partial, triggered updates. Regardless of this distinction, all distance-vector protocols have a limited view of the network topology (often called 'routing by rumor'), rely on hop count or composite metrics, and converge more slowly than link-state protocols in large networks. The correct options highlight these general characteristics of distance-vector protocols.

Answer

Routers maintain a complete map of the entire network topology.

Answer

Routers use the Shortest Path First (SPF) algorithm to calculate routes.

Answer

Routers flood link-state advertisements (LSAs) to all routers in the area.

Question 15

Which three of the following statements about the routing table lookup process on a Cisco router are true? (Choose three.)

Accepted Answer

The router performs a longest prefix match to select the most specific route for a destination IP.. The routing table uses longest prefix match (A) to find the most specific route. The default route (C) is used only when no other route matches. Directly connected routes (F) are automatically installed when the interface is up/up. Option D is incorrect because the router does recursively resolve the next‑hop IP when it is not directly connected.

Answer

If an exact match is found for the destination network, the router will forward the packet regardless of any more specific routes.

Answer

The router does not perform recursive resolution when the next-hop IP address is not directly connected.

Answer

The router always prefers routes with a higher administrative distance over those with a lower administrative distance.