Question 267 of 1,819
IP RoutinghardMultiple ChoiceObjective-mapped

Quick Answer

The answer is the static route to 10.1.1.128/25 because the router always uses the longest prefix match first when forwarding packets. This means the router compares the destination address against all routes and selects the one with the most specific subnet mask—the narrowest range that still contains the address. For 10.1.1.130, the /25 mask is more specific than /24 or /16, so it wins regardless of administrative distance or metric. On the CCNA 200-301 v2 exam, this concept tests your understanding that route selection begins with prefix length, not AD; a common trap is assuming a static route’s low AD automatically beats a more specific dynamic route. Remember the golden rule: longest match first, then AD, then metric. A helpful mnemonic is “LAM” — Longest match, then Administrative distance, then Metric.

CCNA IP Routing Practice Question

This 200-301 practice question tests your understanding of ip routing. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. A key principle to apply: a Cisco router selects the route with the longest matching prefix to forward packets to the destination IP address.. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

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?

Question 1hardmultiple choice
Review the full routing breakdown →

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

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.

Key principle: A Cisco router selects the route with the longest matching prefix to forward packets to the destination IP address.

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

    This is correct because 10.1.1.130 belongs to the 10.1.1.128/25 range, and /25 is the longest matching prefix shown.

    Related concept

    A Cisco router selects the route with the longest matching prefix to forward packets to the destination IP address.

  • The default route

    Why it's wrong here

    This is wrong because a default route is a last resort. Since more specific routes exist, it is not used.

    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

    This is wrong because although 10.1.1.130 does fall within 10.1.1.0/24, that route is less specific than 10.1.1.128/25.

    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

    This is wrong because the /16 route is even less specific than the /24.

    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

This is correct because 10.1.1.130 belongs to the 10.1.1.128/25 range, and /25 is the longest matching prefix shown.

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?”

Common exam traps

Common exam trap: answer the scenario, not the keyword

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.

Detailed technical explanation

How to think about this question

Routing decisions in Cisco routers rely primarily on the longest prefix match principle, which means the router selects the route with the most specific subnet mask that includes the destination IP address. In this question, the destination IP 10.1.1.130 falls within multiple routes: 10.1.0.0/16, 10.1.1.0/24, and 10.1.1.128/25. The /25 subnet mask is the longest prefix, making it the most specific route. This specificity ensures packets are forwarded along the most precise path available, optimizing network efficiency and reducing unnecessary hops. When multiple routes match a destination, the router first compares prefix lengths to find the longest match. Only if two or more routes have the same prefix length does the router consider administrative distance and metric to choose the best path. In this scenario, the static route to 10.1.1.128/25 is the most specific, so it is selected regardless of the presence of OSPF routes or the default route. This behavior aligns with Cisco’s routing logic and is critical for understanding route selection in complex routing tables. A common exam trap is to assume the router always prefers routes with the lowest administrative distance or OSPF routes over static routes. However, the router prioritizes prefix length first, not administrative distance, unless prefix lengths tie. Practically, this means a static route with a longer prefix mask will override less specific OSPF routes or default routes. Understanding this hierarchy prevents misinterpretation of routing behavior and ensures accurate troubleshooting and configuration in Cisco networks.

KKey Concepts to Remember

  • A Cisco router selects the route with the longest matching prefix to forward packets to the destination IP address.
  • When multiple routes match a destination, the router compares prefix lengths before considering administrative distance or metrics.
  • Static routes with longer prefix masks override less specific dynamic routes like OSPF or default routes in route selection.
  • The default route is only used when no more specific matching routes exist in the routing table.
  • OSPF routes are preferred over static routes only if they have the same prefix length and a lower administrative distance.
  • Routers install the most specific route in the routing table to optimize packet forwarding efficiency.
  • Administrative distance is a secondary factor used only when prefix lengths are identical among multiple routes.
  • Misinterpreting routing precedence between prefix length and administrative distance is a common exam mistake.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

A Cisco router selects the route with the longest matching prefix to forward packets to the destination IP address.

Real-world example

How this comes up in practice

A network engineer at a university connects two campus buildings via a fibre link. Both routers run OSPF, but no adjacency forms — even though both routers can ping each other. The engineer finds one router is in area 0 and the other in area 1. OSPF adjacency requires matching area numbers, hello/dead timers, and network type. IP reachability alone is not enough.

What to study next

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Review a Cisco router selects the route with the longest matching prefix to forward packets to the destination IP address., then practise related 200-301 questions on the same topic to reinforce the concept.

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FAQ

Questions learners often ask

What does this 200-301 question test?

IP Routing — This question tests IP Routing — A Cisco router selects the route with the longest matching prefix to forward packets to the destination IP address..

What is the correct answer to this question?

The correct answer is: 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.

What should I do if I get this 200-301 question wrong?

Review a Cisco router selects the route with the longest matching prefix to forward packets to the destination IP address., then practise related 200-301 questions on the same topic to reinforce the concept.

What is the key concept behind this question?

A Cisco router selects the route with the longest matching prefix to forward packets to the destination IP address.

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Same concept, more angles

1 more ways this is tested on 200-301

These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.

Variation 1. A router has these routes in its routing table: O 172.16.0.0/16 O 172.16.20.0/24 S 172.16.20.128/25 A packet destined for 172.16.20.200 arrives. Which route will the router use?

medium
  • A.172.16.0.0/16
  • B.172.16.20.0/24
  • C.172.16.20.128/25
  • D.The default route

Why C: Routers choose the most specific matching route. The destination 172.16.20.200 falls within 172.16.20.128/25, so that static route is used even though broader matches also exist.

Last reviewed: May 17, 2026

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