CCNA IP Routing Practice Question
Exhibit
R1# show ip route O 10.1.1.0/24 [110/20] via 192.0.2.2, GigabitEthernet0/0 S 10.1.1.128/25 [1/0] via 192.0.2.6 O 10.1.0.0/16 [110/30] via 192.0.2.10, GigabitEthernet0/1 S* 0.0.0.0/0 [1/0] via 198.51.100.1
A packet destined for 10.1.1.130 arrives at the router. Based on the routing table, which route will be used?
⚠ Common exam trap
A frequent exam trap is to mistakenly select the default route or a less specific OSPF route because they appear in the routing table. Candidates often overlook that routers prioritize the longest prefix match before considering administrative distance or route type. This leads to choosing the default route or a broader subnet like 10.1.1.0/24 or 10.1.0.0/16 instead of the more specific static route 10.1.1.128/25. Misunderstanding this can cause incorrect answers and confusion about how Cisco routers forward packets.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The static route to 10.1.1.128/25
Routers do not choose the route with the lowest administrative distance first when several routes match a destination. They begin with the most specific matching prefix. In practical terms, the router looks for the narrowest route that still contains the destination address. The packet is going to 10.1.1.130. That address fits inside 10.1.1.128/25, and it also fits inside 10.1.1.0/24 and 10.1.0.0/16. But /25 is the most specific of those matches, so the router uses it. Only after determining that two routes have the same prefix length would the router consider administrative distance and metric. The default route is ignored because more specific matches exist.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The static route to 10.1.1.128/25
Why this is correct
The static route to 10.1.1.128/25 is chosen because the router performs a longest prefix match (LPM) on the destination address. 10.1.1.130 falls within the range 10.1.1.128–10.1.1.255, and the /25 prefix length (25 bits) is the most specific match among all routes in the routing table. Even though other routes exist, this one has the greatest number of bits matching the destination, so it is preferred regardless of administrative distance or metric.
- ✗
The default route
Why it's wrong here
The default route, typically 0.0.0.0/0, is the least specific possible route and is used only as a last resort when no other route in the routing table matches the destination prefix. Because a more specific route (10.1.1.128/25) exactly matches 10.1.1.130, the default route is never consulted. Default routes are only selected when the destination address does not fall within any other advertised or configured network prefix.
When this WOULD be correct
If the question specified that there were no specific routes for 10.1.1.130 and only a default route was configured, then the default route would be the correct answer. For example, if the routing table only contained a default route and no other specific routes, this option would apply.
- ✗
The OSPF route to 10.1.1.0/24
Why it's wrong here
The OSPF route to 10.1.1.0/24 is a valid match for 10.1.1.130, but it is not the longest match. The /24 prefix length covers addresses 10.1.1.0–10.1.1.255, yet the static /25 route is a subset of this range with a longer prefix (25 bits). Since the router always selects the route with the most specific prefix, the /25 static route is preferred over this OSPF /24 route, even though the /24 is also a direct match.
When this WOULD be correct
If the question specified that the router was configured to use OSPF as the primary routing protocol and that the static route was not present or had a lower administrative distance, then the OSPF route to 10.1.1.0/24 would be the correct answer for routing the packet to 10.1.1.130.
- ✗
The OSPF route to 10.1.0.0/16
Why it's wrong here
The OSPF route to 10.1.0.0/16 is not used because its prefix length is only 16 bits, making it far less specific than the /25 static route. While 10.1.1.130 does lie within this /16 range, the router's forwarding decision is based on the longest matching prefix, not the classification of the address or the routing protocol's preference. A /16 route is a summary that covers many /24 and /25 subnets, so it can never override a more specific route that matches the destination.
When this WOULD be correct
In a different question scenario where the routing table only contains the OSPF route to 10.1.0.0/16 and no more specific routes, a packet destined for any address within that subnet, including 10.1.1.130, would correctly use this route as the best match.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓The static route to 10.1.1.128/25Correct answer▾
Why this is correct
The static route to 10.1.1.128/25 is chosen because the router performs a longest prefix match (LPM) on the destination address. 10.1.1.130 falls within the range 10.1.1.128–10.1.1.255, and the /25 prefix length (25 bits) is the most specific match among all routes in the routing table. Even though other routes exist, this one has the greatest number of bits matching the destination, so it is preferred regardless of administrative distance or metric.
✗The default routeWrong answer — click to see why▾
Why this is wrong here
The default route (0.0.0.0/0) is only used when no other more specific route matches the destination. Since there are routes with longer prefixes (e.g., /25, /24) that match 10.1.1.130, the default route is not considered.
★ When this WOULD be the correct answer
If the question specified that there were no specific routes for 10.1.1.130 and only a default route was configured, then the default route would be the correct answer. For example, if the routing table only contained a default route and no other specific routes, this option would apply.
Why candidates choose this
Students might think the default route is always used as a catch-all, but it is only a last resort. Without understanding longest prefix match, they may incorrectly assume the default route applies.
✗The OSPF route to 10.1.1.0/24Wrong answer — click to see why▾
Why this is wrong here
Although 10.1.1.130 falls within the 10.1.1.0/24 network, the /25 route is more specific (longer prefix). The router always prefers the longest matching prefix, so the /24 route is not used.
★ When this WOULD be the correct answer
If the question specified that the router was configured to use OSPF as the primary routing protocol and that the static route was not present or had a lower administrative distance, then the OSPF route to 10.1.1.0/24 would be the correct answer for routing the packet to 10.1.1.130.
Why candidates choose this
A student might see that the destination is within the /24 range and think it matches, but forget that a more specific route (like /25) takes precedence. This is a common confusion between prefix length and route selection.
✗The OSPF route to 10.1.0.0/16Wrong answer — click to see why▾
Why this is wrong here
The /16 route is the least specific among the matching routes. The router will not use it because there are longer prefix matches (/24 and /25) that are more specific to the destination.
★ When this WOULD be the correct answer
In a different question scenario where the routing table only contains the OSPF route to 10.1.0.0/16 and no more specific routes, a packet destined for any address within that subnet, including 10.1.1.130, would correctly use this route as the best match.
Why candidates choose this
Students might think that a larger network (like /16) is more likely to be used, but in routing, specificity (longer prefix) is key. They may confuse network size with route preference.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Visual reference
Quick reference
Routing Protocol Comparison
| Protocol | Metric | Max Hops | Algorithm | Type |
|---|---|---|---|---|
| RIP v2 | Hop count | 15 | Bellman-Ford | Distance vector |
| OSPF | Cost (bandwidth) | Unlimited | Dijkstra (SPF) | Link state |
| EIGRP | Composite metric | Unlimited | DUAL | Hybrid |
| IS-IS | Cost | Unlimited | Dijkstra | Link state |
| BGP | Policy / attributes | Unlimited | Path vector | Path vector |
RIP's 15-hop limit makes it unsuitable for large networks. OSPF and EIGRP dominate modern enterprise deployments.
Go deeper
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Key term
Router
A router is a networking device that connects different networks together and directs data traffic between them by choosing the best path for data to travel.
Key term
Administrative distance
Administrative distance is a number that a router uses to decide which routing protocol's route to trust when it learns about the same destination from multiple different routing protocols.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-301 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 200-301 exam.