Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
Exhibit
R1# show ip route O 192.168.10.0/24 [110/20] via 192.0.2.2 S 192.168.10.128/25 [1/0] via 192.0.2.6 S* 0.0.0.0/0 [1/0] via 198.51.100.1 Destination being tested: 192.168.10.130
Based on the exhibit, which route will be used for destination 192.168.10.130?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
The static route to 192.168.10.128/25
This is correct because 192.168.10.130 is inside the more specific /25 prefix.
B
Distractor review
The OSPF route to 192.168.10.0/24
This is wrong because the /24 is less specific than the /25.
C
Distractor review
The default route
This is wrong because a more specific route exists.
D
Distractor review
No route at all
This is wrong because the destination clearly matches multiple routes shown.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A common exam trap is to select the OSPF route to 192.168.10.0/24 because it appears as a valid route to the destination. Candidates may mistakenly believe that dynamic routing protocols override static routes or that the broader /24 subnet is sufficient. However, the router always prefers the longest prefix match, which is the /25 static route in this case. Another trap is assuming the default route will be used when multiple routes exist, but default routes only apply when no specific routes match the destination. Misunderstanding these routing principles leads to incorrect answers.
Technical deep dive
How to think about this question
Routing decisions in Cisco devices rely heavily on the concept of longest prefix match, where the router selects the route with the most specific subnet mask that matches the destination IP address. In this question, the destination IP 192.168.10.130 falls within both the 192.168.10.0/24 and 192.168.10.128/25 networks. The /25 subnet mask (255.255.255.128) is more specific than the /24 (255.255.255.0), meaning it covers a smaller range of IP addresses and thus provides a more precise route. When multiple routes match a destination, Cisco routers use the longest prefix match rule to determine which route to install in the routing table and use for forwarding packets. Even if a less specific route like 192.168.10.0/24 is learned via OSPF, the router will prefer the static route to 192.168.10.128/25 because static routes typically have a lower administrative distance and the prefix is longer, making it the best match. The exam trap here is assuming that dynamic routing protocols like OSPF always take precedence or that the default route will be used if multiple routes exist. In reality, the router always prefers the most specific route regardless of the routing protocol, and default routes are only used when no more specific routes exist. This behavior ensures efficient and accurate packet forwarding in complex networks.
KKey Concepts to Remember
- Cisco routers use the longest prefix match rule to select the most specific route for forwarding packets to a destination IP address.
- A route with a longer subnet mask (higher prefix length) is preferred over routes with shorter subnet masks when multiple matches exist.
- Static routes generally have a lower administrative distance than dynamic routing protocols like OSPF, making them preferred if prefix lengths are equal.
- Dynamic routing protocols such as OSPF advertise routes with less specific prefixes but do not override more specific static routes.
- Default routes are only used when no other more specific routes exist in the routing table for the destination IP address.
- The router installs the route with the longest matching prefix in the routing table and uses it for packet forwarding.
- Misinterpreting routing precedence or ignoring prefix length leads to common exam mistakes in route selection questions.
- Understanding subnetting and prefix lengths is critical for correctly determining which route a Cisco router will use.
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.
Related practice questions
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
Cisco routers use the longest prefix match rule to select the most specific route for forwarding packets to a destination IP address.
What is the correct answer to this question?
The correct answer is: The static route to 192.168.10.128/25 — The route used will be the one with the longest matching prefix. In practical terms, 192.168.10.130 matches both the /24 and the /25 prefixes shown, but the /25 is more specific. Because longest-prefix match comes first, the router uses the /25 route even though other matching routes are present. This is a clean route-table interpretation question that is very close to real exam reasoning.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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