CCNA IP Routing Practice Test 12 — 15 Questions

Question 1

An OSPF-enabled router R1 fails to advertise the 192.168.50.0/24 network to neighbor R2, even though the neighbor relationship is up. Which misconfiguration on R1 would cause this?

Accepted Answer

The wildcard network statement does not match 192.168.50.0/24. If the network statement on R1 does not match the interface connected to 192.168.50.0/24, OSPF will not enable on that interface and the subnet will not be advertised. The route stays absent from neighbors despite OSPF running elsewhere.

Answer

The OSPF process must be process ID 50 to advertise 192.168.50.0/24

Answer

OSPF cannot advertise a directly connected LAN

Answer

R2 needs a default route before learning intra-area routes

Question 2

Exhibit: R1 has the static route 'ip route 0.0.0.0 0.0.0.0 192.0.2.2 200' and also learns a default route from OSPF. Which default route will be installed while the OSPF route is present?

Accepted Answer

The OSPF default route. The OSPF external default route wins because its administrative distance is 110, which is lower than the floating static route's distance of 200. The static route is intentionally given a higher AD so it is used only as a backup.

Answer

The static default route

Answer

Both default routes with per-packet load balancing

Answer

Neither route because floating statics suppress dynamic defaults

Question 3

A branch router learns a route to 10.20.30.0/24 from OSPF with metric 30 and also has a static route to the same prefix with an administrative distance of 5. Which route will appear in the routing table?

Accepted Answer

The static route because its administrative distance is lower. The router installs the static route because administrative distance is compared before metric when two different routing sources advertise the same prefix. OSPF metric matters only against other OSPF choices, not against a lower-AD static route.

Answer

The OSPF route because metric 30 is lower than the static route metric

Answer

Both routes with equal preference because they point to the same prefix

Answer

Neither route until the router performs a full SPF recalculation

Question 4

R1 and R2 are directly connected via Ethernet on interface G0/0. Both interfaces are in the same subnet and configured for OSPF area 0. After enabling OSPF, R1's G0/0 is stuck in the INIT state in the OSPF neighbor table. What is the most likely cause?

Accepted Answer

Hello and dead timer mismatch. Being stuck in the INIT state means R1 has received Hello packets from R2 but has not transitioned to the 2-WAY state. This most often occurs when critical OSPF parameters like the hello and dead timers do not match. An MTU mismatch, while problematic, would cause the adjacency to fail during database exchange (Exstart/Exchange), not during initial neighbor formation. Missing router IDs are not a real issue because routers auto-generate them, and a duplicate static route to the connected subnet would not affect OSPF neighbor discovery.

Answer

MTU mismatch

Answer

Missing router ID on both routers

Answer

A duplicate static route to 10.1.12.0/30

Question 5

R1 and R2 are directly connected. Their interfaces are up/up and belong to the same subnet. R1's OSPF configuration places the interface in area 0, while R2's interface is in area 1. R1 does not show R2 as an OSPF neighbor. What is the most likely cause?

Accepted Answer

The area IDs do not match. OSPF neighbors on the same link must agree on the area ID. Here, one side is in area 0 and the other is in area 1, so adjacency never forms even though the interfaces are up and in the same subnet.

Answer

R1 must use a loopback as the router ID

Answer

The subnet mask is too small for OSPF to work

Answer

R2 should be configured as the DR manually

Question 6

A router has two static routes to the same 192.168.1.0/24 network: one via next-hop 10.1.1.1 with metric 10, and the other via next-hop 10.1.1.2 with metric 5. Both routes use the default administrative distance of 1. Which next hop does the router use to forward packets to this destination?

Accepted Answer

10.1.1.2 because it has the lower metric. Both routes have the same prefix length and the same administrative distance. The route with the lower metric is preferred for a static route when the AD is equal only if different metrics are configured, and here the route via 10.1.1.2 has metric 5 versus metric 10.

Answer

10.1.1.1 because it appears first in the configuration

Answer

Both next hops because all static routes always load balance

Answer

Neither next hop because static routes need tracking to be installed

Question 7

Exhibit: R1 has a default route pointing to 10.1.1.2. Users lose internet access when that next hop fails, even though a floating static backup exists. Why is the backup not installed?

Accepted Answer

The primary static route remains installed because there is no tracking to remove it. A floating static route is used only when the primary route disappears from the routing table. If the primary interface stays up and the next hop becomes unreachable beyond that segment, the route can remain installed unless tracking or another detection mechanism removes it.

Answer

The backup route has a higher administrative distance and therefore is never considered

Answer

Floating statics work only with dynamic routing protocols

Answer

The backup route must use the same next hop as the primary route

Question 8

A router learns 172.16.40.0/24 from OSPF with AD 110 and metric 20. It also learns the same prefix from EIGRP with AD 90 and feasible distance 30720. Which route is installed?

Accepted Answer

The EIGRP route because its administrative distance is lower. When the same prefix is learned from different routing protocols, the router compares administrative distance first. EIGRP internal routes have AD 90, which beats OSPF AD 110, so the EIGRP path goes into the table.

Answer

The OSPF route because metric 20 is lower than 30720

Answer

Both routes because ECMP is automatic across different protocols

Answer

Neither route until one is redistributed into the other protocol

Question 9

Exhibit: R3 learns 10.50.0.0/16 by OSPF through two equal-cost paths. What will R3 do by default?

Accepted Answer

Install both routes and load balance. When OSPF has equal-cost routes to the same destination, the router installs multiple paths and can load balance across them, assuming the platform supports the default maximum-paths value.

Answer

Choose the route from the neighbor with the highest router ID only

Answer

Install only one route because OSPF does not support ECMP

Answer

Prefer the path with the lower next-hop IP address

Question 10

Exhibit: A router has the following routes in its routing table:
- OSPF: 10.1.1.0/24
- Static: 10.1.1.128/25
- Default: 0.0.0.0/0

A packet is destined for 10.1.1.130. Which route does the router use?

Accepted Answer

The static 10.1.1.128/25 route. Routers use longest-prefix match before they think about metrics. The /25 route for 10.1.1.128/25 is more specific than the /24 or the default route, so traffic for 10.1.1.130 follows that path.

Answer

The OSPF 10.1.1.0/24 route

Answer

The default route

Answer

The router load-balances across all three

Question 11

Exhibit: R1 has a static default route to 192.0.2.2 and also learns a default route from OSPF. Which default route is installed in the routing table?

Accepted Answer

The static default route because its administrative distance is lower. When two routes to the same prefix are learned from different sources, the router compares administrative distance first. A static route has AD 1 by default, while OSPF has AD 110, so the static default route wins unless its AD was changed manually.

Answer

The OSPF default route because dynamic routes are preferred

Answer

Both default routes because they have the same prefix length

Answer

Neither route until a floating static route is configured

Question 12

A router advertises its LAN network into OSPF, but no OSPF Hellos should be sent toward end-user devices on that LAN. Which configuration approach solves this cleanly?

Accepted Answer

Configure the LAN interface as a passive interface in OSPF. A passive interface advertises the connected subnet into OSPF without sending or processing Hellos on that interface. That is exactly what you want for user-facing LANs with no OSPF neighbors.

Answer

Use ip ospf cost 65535 on the LAN interface

Answer

Disable OSPF globally and redistribute connected routes

Answer

Convert the LAN interface to a loopback

Question 13

On a broadcast multiaccess segment, R3 has an OSPF priority of 255, but it is in the DROTHER state. Which explanation best fits OSPF behavior?

Accepted Answer

DR election is nonpreemptive on broadcast networks. On broadcast networks, OSPF DR and BDR election is not preemptive. If a DR is already elected, giving another router a higher priority later does not force a new election unless the current DR goes down or OSPF is reset on the segment.

Answer

A router cannot become DR if it uses a loopback router ID

Answer

OSPF priority works only on point-to-point links

Answer

R3's priority is lower than the current DR's priority

Question 14

R1 is not forming an OSPF adjacency with R2 on GigabitEthernet0/1. Which mismatch below is the most likely cause?

Accepted Answer

The routers are using different IP subnet masks on the shared link. For OSPF neighbors to form, key settings on a shared segment must match. A subnet mask mismatch on a broadcast network often prevents proper neighbor formation because the routers do not agree on the local network.

Answer

OSPF cannot run on GigabitEthernet interfaces

Answer

Both routers are in area 0

Answer

The router IDs must match for adjacency to form

Question 15

Exhibit: OSPF neighbors are not reaching FULL state on an Ethernet segment with multiple routers. The output of show ip ospf neighbor on R2 shows a neighbor in the 2WAY/DROTHER state. What is the most likely reason?

Accepted Answer

The 2WAY state with another DROTHER on a broadcast segment is normal. On a broadcast Ethernet network, two routers normally become fully adjacent through the DR or BDR. If the local router is stuck in 2WAY with another DROTHER, that is normal behavior. It is not a fault by itself.

Answer

Authentication mismatch between R2 and 3.3.3.3

Answer

R2 must be configured as a point-to-point network type

Answer

R2 has a duplicate router ID