CCNA IP Routing Practice Test 11 — 15 Questions

Question 1

A router pair is directly connected, but they do not become OSPF neighbors. IP addressing and area assignment are correct. What is the most likely cause?

Accepted Answer

OSPF network type mismatch on the connected interfaces. OSPF network type mismatch is a frequent reason for adjacency failure when basic IP and area settings are correct. If one side is configured as broadcast and the other as point-to-point, the hello timers, neighbor discovery behavior, and designated router election rules diverge, preventing neighbor formation. Unlike process IDs (which are locally significant), a mismatch in network type directly affects how OSPF hellos are processed. This is a well-known L2/L3 misconfiguration that must be checked alongside router‑ID and authentication parameters.

Answer

Duplicate default routes on both routers

Answer

Missing VLAN trunking on the link

Answer

The OSPF process IDs are required to match

Question 2

A router has both an OSPF route and a static route to the same destination. The static route has an administrative distance of 200. What is the expected behavior while the OSPF route remains available?

Accepted Answer

The static route remains a backup and is used only if the OSPF route is lost.. The static route with an administrative distance of 200 behaves as a floating backup. In plain language, the router keeps it in reserve and prefers the OSPF route while OSPF is healthy, because OSPF’s default administrative distance of 110 is lower and therefore more trusted. The static route does not disappear from the configuration, but it stays out of the active routing table unless the better route is lost.

This is a very common CCNA concept because it shows how routing preference works between different route sources. The higher-distance static route is not useless; it is intentionally configured so that it becomes active only during a failure. That design provides backup routing without interfering with the normal dynamic path. The correct answer is the one describing the static route as a standby or floating route rather than as the preferred path.

Answer

The static route overrides OSPF immediately because static routes always win.

Answer

Both routes must be installed simultaneously because they point to the same destination.

Answer

The router removes the OSPF route because the static route has a manually configured distance.

Question 3

A route to 10.10.20.0/24 disappears when an OSPF adjacency fails. Which design would most directly provide an automatic backup without changing the primary OSPF path during normal operation?

Accepted Answer

A floating static route with a higher administrative distance than OSPF. The most direct design is a floating static route with a higher administrative distance than OSPF. In plain language, that means the router keeps a manually configured backup route in reserve but does not use it while the OSPF route remains healthy. If the OSPF path disappears, the backup static route becomes active automatically. This is a very common and practical way to add simple failover.

The key requirement in the question is that the primary OSPF path should remain unchanged under normal conditions. A normal static route with default distance would override OSPF and break that goal. A floating static route avoids that by staying less preferred until a failure occurs. That is why it is the correct design choice here.

Answer

A standard static route with the default administrative distance of 1

Answer

Removing OSPF entirely and using only a default route

Answer

Disabling the routing table on the router until failure occurs

Question 4

A router learns the same destination from EIGRP and OSPF. The EIGRP route has a metric of 1000, and the OSPF route has a metric of 10. Which route is installed by default?

Accepted Answer

The EIGRP route, because its source has a lower default administrative distance. The EIGRP route is installed by default because route selection between different routing protocols is based on administrative distance before the protocol-specific metric is compared across sources. In plain language, the router does not compare an OSPF metric of 10 directly against an EIGRP metric of 1000 because those metrics come from different systems and are not numerically comparable in a meaningful cross-protocol way. Instead, the router first looks at the trustworthiness of the source.

By default, internal EIGRP routes have a lower administrative distance than OSPF routes, so EIGRP wins even though the OSPF metric value appears lower. This is a classic CCNA trap designed to catch people who compare metrics across different protocols without considering administrative distance first.

Answer

The OSPF route, because 10 is lower than 1000

Answer

Both routes automatically install for load balancing

Answer

Neither route installs until the administrator chooses manually

Question 5

A route to 192.168.1.0/24 appears in the routing table from OSPF, but a more specific static route to 192.168.1.128/25 is also configured. Which route is used for traffic to 192.168.1.200?

Accepted Answer

The static /25 route. The static /25 route is used because longest-prefix match prefers the most specific matching route. In plain language, even though the OSPF /24 route covers the destination, the /25 static route covers a narrower range and therefore wins for addresses inside that upper half of the subnet.

The router does not begin by asking which protocol is more trusted unless the prefix lengths are equal among the matching routes.

Answer

The OSPF /24 route

Answer

Both routes automatically load-balance

Answer

Neither route because the network overlaps

Question 6

Which two statements accurately describe OSPF route selection or behavior at the CCNA level?

Accepted Answer

OSPF uses cost as its metric for choosing paths within OSPF.. Option A is correct because OSPF's metric is cost, which is derived from interface bandwidth (cost = reference bandwidth / interface bandwidth) and accumulated along the path, so the lowest total cost path is preferred within OSPF. Option C is correct because when OSPF competes with routes from other sources (static, EIGRP, RIP, etc.), the router uses administrative distance to decide which route source is trusted first; OSPF's default AD is 110. Option B is wrong because metrics from different routing protocols are not directly comparable — administrative distance, not the metric value, determines route preference across protocols. Option D is wrong because OSPF process IDs are locally significant and do not need to match between neighbors. Option E is wrong because OSPF supports equal-cost multipath (ECMP) and can install multiple equal-cost routes into the routing table.

Answer

OSPF compares its metric directly against EIGRP metrics across protocols.

Answer

OSPF process IDs must match between all neighboring routers.

Answer

OSPF can never install equal-cost paths.

Question 7

Why is route summarization often useful at distribution or area boundaries in larger networks?

Accepted Answer

It reduces the number of route advertisements by combining multiple specific prefixes. Route summarization is useful there because it reduces the number of specific prefixes that must be advertised upstream or across boundaries. In plain language, instead of sending many small route entries, the network can often advertise one broader summary that represents them collectively. This helps control routing-table growth and can make the design more scalable and easier to manage.

Summarization does not eliminate the need for routing detail inside the local area, but it can simplify what needs to be shared outward. That is why it is especially valuable at aggregation points such as distribution layers or area boundaries.

Answer

It forces all users into the same VLAN

Answer

It automatically encrypts routing protocols

Answer

It removes the need for IP addressing

Question 8

A router receives two routes to 10.50.0.0/16: one from OSPF and one static route with an administrative distance of 90. Which route is installed by default?

Accepted Answer

The static route, because its administrative distance is lower than OSPF's. By default, the static route with administrative distance 90 is installed because it is preferred over the OSPF route with default administrative distance 110. In plain language, the router is being told that the manually configured route is more trustworthy than the OSPF-learned one, so it chooses the static path first. The protocol type alone does not decide the outcome. Administrative distance is the key comparison when two different route sources offer the same destination prefix length.

This is a classic routing-selection question because many learners incorrectly assume OSPF always wins over static routes unless the static route uses the default administrative distance. Once the static route is given a value lower than OSPF’s 110, it becomes the preferred path unless a more specific route exists elsewhere.

Answer

The OSPF route, because dynamic routes always override static routes

Answer

Both routes, because equal destination networks always load-balance

Answer

Neither route, because the destinations overlap

Question 9

Which two statements accurately describe route summarization?

Accepted Answer

It can reduce the number of individual routes that must be advertised.. Route summarization combines multiple specific routes into a smaller number of broader advertisements. In plain language, it lets a router describe a group of networks with one shorter, more general route instead of announcing each one individually. This can reduce routing-table size and improve scalability. It can also reduce the amount of routing information that must be exchanged across certain boundaries.

The wrong answers often confuse summarization with default routing or encryption. The two correct statements are the ones that preserve its aggregation and scaling purpose.

Answer

It forces every router to use only a default route.

Answer

It is the same thing as PAT overload.

Answer

It automatically encrypts routing updates.

Question 10

Two routers are in the same OSPF area and on the same subnet, but they do not form an adjacency. One interface uses a hello interval of 10 seconds and the other uses 5 seconds. What is the most likely cause?

Accepted Answer

The OSPF hello timers do not match.. An OSPF timer mismatch is the most likely cause. In plain language, the routers are trying to discover each other, but they are speaking on different timing expectations. OSPF neighbors on the same segment must agree on certain parameters before they trust each other enough to form an adjacency, and the hello and dead timers are among those critical values.

This is a very common OSPF troubleshooting issue because the interfaces may still be reachable with ping and may even appear correctly addressed and placed in the same area. But OSPF is stricter than simple IP reachability. If the hello interval does not match, the adjacency usually fails before it becomes fully operational.

Answer

The routers need matching hostnames.

Answer

The subnet must be changed to /24 before OSPF can work.

Answer

The routers must both use static routes first.

Question 11

An OSPF-enabled router has two paths to the same destination network, and both paths have the same OSPF cost. What is the most likely default behavior?

Accepted Answer

Install both routes and use equal-cost multipath forwarding. When OSPF learns two equally good paths to the same destination, the router can install both and perform equal-cost multipath forwarding. In plain language, the router does not have to throw one away simply because there are two valid answers. If the routes are truly equal from OSPF’s perspective, it can use both paths to improve resilience and share traffic.

This is a classic routing behavior question because many candidates assume the router must always choose only one best path. In reality, equal-cost multipath is a normal feature in many routing environments. The key is that the paths must be equally good according to the protocol’s metric logic.

Answer

Discard both routes because OSPF cannot handle duplicates

Answer

Always keep only the route learned first

Answer

Replace both routes with a default route

Question 12

A static default route is configured with an administrative distance of 250. What is the most likely design intention?

Accepted Answer

To keep the route as a backup of last resort behind normal learned routes. The design intention is to make the static default route a very low-priority backup path. In plain language, the administrator wants the route to exist only as a last resort behind almost any normal learned path. By assigning such a high administrative distance, the route stays out of the active table unless better routes disappear.

This is a floating-static design concept. The route is not meant to be primary. It is intentionally configured to sit in reserve and become relevant only during failure conditions or severe loss of normal routing information.

Answer

To make the route override all dynamic routing immediately

Answer

To disable default routing entirely

Answer

To convert the default route into a host route

Question 13

A packet is destined for 192.168.40.130. The routing table contains 192.168.40.0/24, 192.168.40.128/25, and 0.0.0.0/0. Which route is used?

Accepted Answer

192.168.40.128/25. The /25 route is used because it is the most specific matching prefix. In plain language, even though the /24 and the default route also technically match, the router prefers the entry that most precisely describes the destination range. Since 192.168.40.130 falls inside 192.168.40.128/25, that route wins under longest-prefix match.

This is a classic routing-table interpretation pattern. The router does not start with the default route when more specific routes exist, and it does not choose the /24 simply because it is familiar. Specificity comes first.

Answer

192.168.40.0/24

Answer

0.0.0.0/0

Answer

No route can be used because the entries overlap

Question 14

Which two statements accurately describe OSPF passive interfaces?

Accepted Answer

It prevents OSPF from sending hello packets on that interface.. An OSPF passive interface stops hello packet exchange on that interface while still allowing the connected network to be advertised into OSPF through other active adjacencies. In plain language, it tells the router not to try to form neighbors on that interface, but not to forget that the network exists. This is very useful on user-facing or stub-like interfaces where no routing neighbor should appear.

The wrong answers often treat passive as if it disables OSPF globally or removes the network completely. The two correct answers are the ones that preserve the suppression of adjacency on that interface and the continued advertisement of the connected network.

Answer

It changes OSPF into a static route on that interface.

Answer

It forces the interface to become the router ID.

Answer

It disables OSPF on every interface in the router automatically.

Question 15

Two routers are directly connected over IPv6 and should form an OSPFv3 adjacency, but they do not. Link-local addressing is present on both interfaces. Which issue is most likely to prevent the adjacency?

Accepted Answer

The interfaces are assigned to different OSPFv3 areas.. An area mismatch is a strong and direct explanation. In plain language, even though the routers can have valid IPv6 addressing and proper link-local communication on the interface, OSPFv3 still requires the two ends of the shared segment to agree on the area context for the adjacency. If one side places the interface in one area and the other side places it in another, the routers will not treat each other as valid neighbors.

This is very similar in principle to OSPF for IPv4. Link-local addressing matters in OSPFv3, but the protocol still enforces key neighbor-formation checks. The correct answer is the one that focuses on a required protocol match rather than on a vague issue like hostname or cable color.

Answer

The routers need matching hostnames before OSPFv3 can start.

Answer

IPv6 requires a /64 only for routing protocols to function.

Answer

OSPFv3 cannot run on directly connected interfaces.