CCNA IP Routing Practice Question
A router has a static route to 10.20.20.0/24 and also has a default route. Which route is used for traffic to 10.20.20.8?
⚠ Common exam trap
A frequent exam trap is assuming the default route is used whenever it exists, ignoring the presence of more specific static routes. This misunderstanding leads to incorrect answers because routers always prefer the route with the longest matching prefix, not the default route unless no other matches exist.
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 10.20.20.0/24
The static route to 10.20.20.0/24 is used because it is more specific than the default route. In practical terms, the router always chooses the route that most precisely matches the destination before falling back to the default route. This question reinforces the idea that the default route is a route of last resort, not a preferred choice when a better match already exists.
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 10.20.20.0/24
Why this is correct
The static route to 10.20.20.0/24 is used because routers employ longest prefix match (LPM) to select the most specific route in the routing table. With a destination of 10.20.20.0/24, the /24 prefix has 24 matching bits, whereas the default route has only 0 matching bits. Therefore, the /24 route is preferred and installed as the best route.
- ✗
The default route
Why it's wrong here
The default route, typically 0.0.0.0/0, serves only as a last-resort gateway when no other route matches the destination IP. Because a specific static route exists for 10.20.20.0/24, the router matches that longer prefix first and never evaluates the default route. The default route is still valid but is not used for this particular destination.
When this WOULD be correct
In a different scenario where the router has no specific route to the 10.20.20.0/24 network and only has a default route configured, then traffic to 10.20.20.8 would be directed through the default route, making option B the correct answer.
- ✗
Both routes are used equally
Why it's wrong here
Cisco routers do not load-balance between a specific static route and a default route for the same destination. The routing table selects a single best path based on longest prefix match; once the /24 route is chosen, the default route is neither installed nor considered for that prefix. Equal-cost load balancing applies only among routes with identical prefix lengths.
When this WOULD be correct
In a different scenario where the router has equal-cost multipath (ECMP) routing enabled and both the static route and default route are configured with the same administrative distance, a question could ask which route would be used for load balancing, making this option correct.
- ✗
Neither route is valid
Why it's wrong here
Both routes can be valid entries in the routing table, but the /24 static route clearly matches the destination network, making it a usable path. The default route is also valid as a catch-all for unknown destinations. The route being valid does not mean it wins the lookup; validity is about configuration and reachability, not preference.
When this WOULD be correct
This option would be correct in a scenario where the router has no valid routes configured at all, meaning neither the static route nor the default route is operational due to misconfiguration or failure, leading to an inability to route any traffic.
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 10.20.20.0/24Correct answer▾
Why this is correct
The static route to 10.20.20.0/24 is used because routers employ longest prefix match (LPM) to select the most specific route in the routing table. With a destination of 10.20.20.0/24, the /24 prefix has 24 matching bits, whereas the default route has only 0 matching bits. Therefore, the /24 route is preferred and installed as the best route.
✗The default routeWrong answer — click to see why▾
Why this is wrong here
The default route is used only when there are no more specific routes available. Since the static route to 10.20.20.0/24 is more specific and matches the destination IP 10.20.20.8, it will be used instead of the default route.
★ When this WOULD be the correct answer
In a different scenario where the router has no specific route to the 10.20.20.0/24 network and only has a default route configured, then traffic to 10.20.20.8 would be directed through the default route, making option B the correct answer.
Why candidates choose this
Candidates might choose this option if they misunderstand the concept of route specificity, believing that the default route is always used for any unmatched traffic, rather than recognizing the priority of static routes.
✗Both routes are used equallyWrong answer — click to see why▾
Why this is wrong here
This option is wrong because static routes are preferred over default routes when both are available, and the traffic to 10.20.20.8 matches the static route to 10.20.20.0/24.
★ When this WOULD be the correct answer
In a different scenario where the router has equal-cost multipath (ECMP) routing enabled and both the static route and default route are configured with the same administrative distance, a question could ask which route would be used for load balancing, making this option correct.
Why candidates choose this
Candidates might choose this option due to a misunderstanding of routing priorities, thinking that multiple routes can be used simultaneously without recognizing that static routes take precedence over default routes.
✗Neither route is validWrong answer — click to see why▾
Why this is wrong here
This option is wrong because both the static route to 10.20.20.0/24 and the default route are valid, but the static route is preferred due to its more specific match for the destination IP 10.20.20.8.
★ When this WOULD be the correct answer
This option would be correct in a scenario where the router has no valid routes configured at all, meaning neither the static route nor the default route is operational due to misconfiguration or failure, leading to an inability to route any traffic.
Why candidates choose this
Candidates may choose this option due to a misunderstanding of routing priorities, thinking that if a specific route is not functioning, then no routes can be valid, leading to confusion about the operational status of routes.
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
IPv4 Address Class Summary
| Class | First Octet Range | Default Mask | Networks | Hosts per Network |
|---|---|---|---|---|
| A | 1–126 | /8 (255.0.0.0) | 126 | 16,777,214 |
| B | 128–191 | /16 (255.255.0.0) | 16,384 | 65,534 |
| C | 192–223 | /24 (255.255.255.0) | 2,097,152 | 254 |
| D | 224–239 | N/A | Multicast groups | — |
| E | 240–255 | N/A | Reserved / experimental | — |
127.x.x.x is reserved for loopback. Modern networks use CIDR (classless) rather than classful addressing.
Go deeper
Related to this question
Learn chapter
OSPFv3 Single-Area Configuration for IPv6
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
Static route
A static route is a manually configured path in a router's routing table that tells the router exactly where to send packets for a specific destination network.
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JA
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.