Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
Exhibit
R1# show ip route O 172.20.10.0/24 [110/20] via 192.0.2.2 S 172.20.10.32/27 [1/0] via 192.0.2.6 S* 0.0.0.0/0 [1/0] via 198.51.100.1 Destination being tested: 172.20.10.33
Based on the exhibit, which route will be used to reach 172.20.10.33?
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 172.20.10.32/27
This is correct because 172.20.10.33 falls in the more specific /27 prefix.
B
Distractor review
The OSPF route to 172.20.10.0/24
This is wrong because the /24 is less specific than the /27.
C
Distractor review
The default route
This is wrong because a more specific matching route exists.
D
Distractor review
No route, because the destination does not match any prefix.
This is wrong because the destination clearly matches both prefixes shown.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A common exam trap is to select the OSPF route or the default route instead of the static route with the longer prefix. Candidates often mistakenly believe that dynamic routing protocols like OSPF always take precedence or that default routes are used when any route exists. However, Cisco routers first evaluate the longest prefix match before considering administrative distance. Ignoring this can lead to incorrect answers because the more specific /27 static route will always be preferred over the broader /24 OSPF route or the default route for the destination 172.20.10.33.
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 scenario, the destination IP 172.20.10.33 falls within both the 172.20.10.0/24 and 172.20.10.32/27 subnets, but the /27 subnet is more specific because it covers a smaller range of IP addresses. The router evaluates all available routes and chooses the one with the longest subnet mask first, as it represents a more precise path to the destination. Even if a less specific route like the /24 or a default route exists, the router will prefer the /27 static route because it provides a narrower and therefore more accurate match for 172.20.10.33. A common exam trap is to assume that dynamic routing protocols like OSPF always take precedence over static routes or that default routes are used when any route exists. In reality, Cisco routers prioritize routes based on prefix length first, then administrative distance. Understanding this hierarchy is crucial for correctly interpreting routing tables and answering CCNA questions about route selection.
KKey Concepts to Remember
- A Cisco router selects the route with the longest matching prefix to forward packets to the destination IP address.
- Static routes with more specific subnet masks override less specific dynamic routes when both match the destination.
- The /27 subnet mask is more specific than the /24 mask because it covers fewer IP addresses, providing a more precise route.
- OSPF routes are preferred based on administrative distance but can be overridden by static routes with longer prefix matches.
- Default routes are only used when no more specific route exists in the routing table for the destination IP.
- Routing decisions prioritize prefix length before considering administrative distance or metric values in Cisco devices.
- A destination IP address can match multiple routes, but the router always forwards packets using the most specific route.
- Exam questions often test understanding of longest prefix match to evaluate precise routing table interpretation skills.
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
Related 200-301 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
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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?
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 172.20.10.32/27 — The route used will be the one with the longest matching prefix. In practical terms, 172.20.10.33 matches both the /24 and the /27 shown, but the /27 is more specific. That means the router selects the /27 route before considering the broader /24 or any default route. This is exactly the kind of route-table interpretation the CCNA exam likes because it rewards precise thinking about prefix boundaries.
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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