Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
Exhibit
R1# show ip route R 172.31.80.0/24 [120/1] via 192.0.2.2 S 172.31.0.0/16 [1/0] via 192.0.2.6 Destination being tested: 172.31.80.10
Based on the exhibit, why is traffic to 172.31.80.10 using the RIP route instead of the static route?
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
Because the RIP /24 route is more specific than the static /16 route.
This is correct because longest-prefix match selects the /24 route for that destination.
B
Distractor review
Because RIP always overrides static routing.
This is wrong because static routes can beat RIP when prefix length is the same or more specific.
C
Distractor review
Because static routes cannot be used for private IPv4 space.
This is wrong because static routes work perfectly well with private addressing.
D
Distractor review
Because the static route is automatically removed whenever RIP is enabled.
This is wrong because the static route can still exist in the table for other matching cases.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is assuming that static routes always take precedence over RIP routes because static routes have a lower administrative distance. This misconception ignores the critical role of longest-prefix match in route selection. The router first selects the route with the most specific subnet mask before considering administrative distance. Therefore, a RIP route with a /24 mask will override a static route with a /16 mask for matching traffic. Another trap is thinking that enabling RIP disables or removes static routes, which is incorrect; static routes remain active unless explicitly removed or overridden by a more specific route.
Technical deep dive
How to think about this question
Routing in Cisco devices fundamentally relies on the principle of longest-prefix match, where the router selects the route with the most specific subnet mask that matches the destination IP address. This means that even if a static route has a lower administrative distance, a dynamically learned route with a longer prefix length (more specific subnet) will be preferred. In this scenario, the RIP route with a /24 subnet mask is more specific than the static route with a /16 mask, so traffic destined for 172.31.80.10 matches the RIP route first. The decision process for route selection in Cisco routers involves first identifying all routes that match the destination IP address. Among these, the router selects the route with the longest prefix length. If multiple routes have the same prefix length, the router then compares their administrative distances to choose the best path. Static routes have an administrative distance of 1, which is preferred over RIP's 120, but this only applies when prefix lengths are equal. Because the RIP route is more specific, it overrides the static route despite the higher administrative distance. A common exam trap is assuming that static routes always override dynamic routes due to their lower administrative distance. However, this is only true when prefix lengths are equal. Another mistake is believing that enabling RIP removes static routes automatically, which is false; static routes remain unless manually removed or superseded by a more specific route. Practically, this behavior allows network engineers to use dynamic routing for specific subnets while maintaining broader static routes for general traffic, providing flexible and efficient routing control.
KKey Concepts to Remember
- Routing decisions in Cisco devices use longest-prefix match to select the most specific route to a destination IP address.
- Static routes have a fixed administrative distance of 1, which is lower than RIP's default administrative distance of 120, but prefix length takes priority in route selection.
- RIP advertises routes with a /24 subnet mask that is more specific than a static route with a /16 mask, causing the RIP route to be preferred for matching destinations.
- Cisco routers install the route with the longest matching prefix in the routing table regardless of whether it is learned dynamically or configured statically.
- Static routes remain in the routing table unless explicitly removed or overridden by a more specific route, not simply by enabling a routing protocol like RIP.
- Private IPv4 address space can be routed using both static and dynamic routing protocols without restriction.
- Route preference is determined first by prefix specificity, then by administrative distance when prefix lengths are equal.
- Understanding the interaction between route specificity and administrative distance is critical for troubleshooting routing behavior in Cisco networks.
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.
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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?
Routing decisions in Cisco devices use longest-prefix match to select the most specific route to a destination IP address.
What is the correct answer to this question?
The correct answer is: Because the RIP /24 route is more specific than the static /16 route. — Traffic uses the RIP route because the static route is less specific than the RIP route. In practical terms, longest-prefix match is always evaluated first. Even though the static route is manually configured, the more specific RIP prefix wins because it describes the destination more precisely. This is a strong route-selection item because it tests whether you can prioritize specificity ahead of route source preference.
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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