Quick Answer
The answer is the static route to 10.10.10.128/25 via 198.51.100.2 because routers use the longest prefix match route selection process, which always prefers the most specific network mask. When a packet destined for 10.10.10.200 arrives, the /25 subnet (128–255) covers that host address, while the OSPF /24 route (0–255) is less specific, and the default route is only a last resort. On the CCNA 200-301 v2 exam, this concept tests your understanding of how the routing table is consulted: the router checks for the longest match first, not the lowest administrative distance or metric. A common trap is assuming OSPF or a lower metric wins, but prefix length always takes priority. Remember the memory tip: “The longer the mask, the better the ask”—a more specific subnet always beats a broader one, even if the broader route was learned from a preferred protocol.
This 200-301 practice question tests your understanding of network services and security. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. A key principle to apply: cisco routers forward packets based on the longest prefix match, selecting the route with the most specific subnet mask that matches 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.
R1 has the following routes installed:
O 10.10.10.0/24 via 192.0.2.2 S 10.10.10.128/25 via 198.51.100.2
S* 0.0.0.0/0 via 203.0.113.1
A packet destined for 10.10.10.200 arrives at R1. Which route is used?
The OSPF route to 10.10.10.0/24 via 192.0.2.2
Why wrong: The /24 matches, but the /25 is more specific.
The static route to 10.10.10.128/25 via 198.51.100.2
Longest prefix match makes the /25 win.
The default route via 203.0.113.1
Why wrong: A more specific route exists.
The packet is dropped because OSPF routes cannot overlap with static routes.
Why wrong: Overlapping routes are allowed; the most specific one is chosen.
Answer choices
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 10.10.10.128/25 via 198.51.100.2
Routers forward using longest prefix match first. Even though the OSPF /24 exists, the static /25 is more specific and covers 10.10.10.200, so the packet is sent via 198.51.100.2. The default route is used only when nothing more specific matches.
Key principle: Cisco routers forward packets based on the longest prefix match, selecting the route with the most specific subnet mask that matches the destination IP address.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
The OSPF route to 10.10.10.0/24 via 192.0.2.2
Why it's wrong here
The /24 matches, but the /25 is more specific.
When this WOULD be correct
If the question stated that the packet was destined for an IP address within the 10.10.10.0/24 subnet, such as 10.10.10.50, then the OSPF route would be the correct answer as it matches the destination IP.
The static route to 10.10.10.128/25 via 198.51.100.2
Why this is correct
Longest prefix match makes the /25 win.
Related concept
Cisco routers forward packets based on the longest prefix match, selecting the route with the most specific subnet mask that matches the destination IP address.
The default route via 203.0.113.1
Why it's wrong here
A more specific route exists.
When this WOULD be correct
This option would be correct if the question specified that there were no more specific routes available for the destination address, making the default route the only viable option for routing the packet.
The packet is dropped because OSPF routes cannot overlap with static routes.
Why it's wrong here
Overlapping routes are allowed; the most specific one is chosen.
When this WOULD be correct
In a scenario where the question specifies that OSPF routes are configured to prevent overlapping with static routes, and the routing table is set to drop packets if such overlap occurs, this option would be correct.
Option-by-option analysis
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.
Why this is correct
Longest prefix match makes the /25 win.
Why this is wrong here
The OSPF route to 10.10.10.0/24 matches the destination 10.10.10.200, but the static route to 10.10.10.128/25 has a longer prefix length (25 vs 24), making it more specific. The router uses the longest prefix match, so the OSPF route is not selected.
★ When this WOULD be the correct answer
If the question stated that the packet was destined for an IP address within the 10.10.10.0/24 subnet, such as 10.10.10.50, then the OSPF route would be the correct answer as it matches the destination IP.
Why candidates choose this
Students may think that OSPF routes are preferred over static routes due to administrative distance, but in this case the static route has a longer prefix, which takes precedence regardless of routing protocol.
Why this is wrong here
The default route 0.0.0.0/0 matches any destination, but it is only used when no more specific route exists. Since the static route 10.10.10.128/25 is more specific, the default route is not selected.
★ When this WOULD be the correct answer
This option would be correct if the question specified that there were no more specific routes available for the destination address, making the default route the only viable option for routing the packet.
Why candidates choose this
Students may assume that a default route is always used as a last resort, but they forget that the longest prefix match rule overrides the default route when a more specific match exists.
Why this is wrong here
Overlapping routes are allowed in a routing table; there is no rule that OSPF routes cannot overlap with static routes. The router simply selects the most specific match based on prefix length. The packet is not dropped unless no route matches at all.
★ When this WOULD be the correct answer
In a scenario where the question specifies that OSPF routes are configured to prevent overlapping with static routes, and the routing table is set to drop packets if such overlap occurs, this option would be correct.
Why candidates choose this
Some students might think that overlapping routes cause conflicts or errors, but routers handle overlapping prefixes by using the longest prefix match. The statement about OSPF and static routes being incompatible is incorrect.
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
A common exam trap is assuming that the router will always prefer OSPF routes over static routes because OSPF is a dynamic routing protocol. Candidates may also mistakenly believe that overlapping routes are invalid or cause routing conflicts. In reality, Cisco routers allow overlapping routes and use the longest prefix match rule first, regardless of the routing protocol or administrative distance. This leads to confusion when a static route with a longer prefix exists alongside an OSPF route with a shorter prefix. Misunderstanding this can cause incorrect answers about which route will be used for forwarding packets.
Detailed technical explanation
Routing decisions in Cisco routers rely on the longest prefix match rule, which means the router selects the route with the most specific subnet mask that matches the destination IP address. In this scenario, R1 has three routes: an OSPF-learned route for 10.10.10.0/24, a static route for 10.10.10.128/25, and a default static route 0.0.0.0/0. The destination IP 10.10.10.200 falls within the 10.10.10.128/25 subnet, making the static route the most specific match. This specificity ensures the packet is forwarded via the static route's next-hop address 198.51.100.2. The router uses administrative distance and prefix length to select the best route. Although OSPF routes have a default administrative distance of 110 and static routes have 1, the longest prefix match takes precedence in forwarding decisions. The static route with a /25 mask is more specific than the OSPF /24 route, so it is preferred regardless of the routing protocol. The default route is only used if no other more specific routes match the destination IP. A common exam trap is misunderstanding overlapping routes and assuming that routing protocols cannot coexist with static routes for overlapping subnets. Cisco routers allow overlapping routes and always choose the most specific prefix. Practically, this behavior enables network engineers to override dynamic routes with static routes for certain subnets, providing granular control over traffic paths and redundancy strategies.
Key takeaway
Cisco routers forward packets based on the longest prefix match, selecting the route with the most specific subnet mask that matches the destination IP address.
Real-world example
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
Review cisco routers forward packets based on the longest prefix match, selecting the route with the most specific subnet mask that matches the destination IP address., then practise related 200-301 questions on the same topic to reinforce the concept.
Network Services and Security — study guide chapter
Learn the concepts, then practise the questions
Network Services and Security practice questions
Targeted practice on this topic area only
All 200-301 questions
1,819 questions across all exam domains
CCNA 200-301 v2 study guide
Full concept coverage aligned to exam objectives
200-301 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise 200-301 questions linked to Network Infrastructure and Connectivity.
Practise 200-301 questions linked to Switching and Network Access.
Practise 200-301 questions linked to IP Routing.
Practise 200-301 questions linked to Network Services and Security.
Practise 200-301 questions linked to AI and Network Operations.
Practise IPv4 subnetting, CIDR, masks, host ranges and subnet selection.
Practise OSPF neighbours, router IDs, metrics, areas and routing-table interpretation.
Practise VLANs, access ports, trunks, allowed VLANs and switching scenarios.
Practise spanning tree, root bridge election, port roles and STP troubleshooting.
Practise LACP, PAgP, port-channel behaviour and bundle requirements.
Practise standard and extended ACLs, permit/deny logic and traffic filtering.
Practise static NAT, dynamic NAT, PAT and inside/outside address translation.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Network Services and Security — This question tests Network Services and Security — Cisco routers forward packets based on the longest prefix match, selecting the route with the most specific subnet mask that matches the destination IP address..
The correct answer is: The static route to 10.10.10.128/25 via 198.51.100.2 — Routers forward using longest prefix match first. Even though the OSPF /24 exists, the static /25 is more specific and covers 10.10.10.200, so the packet is sent via 198.51.100.2. The default route is used only when nothing more specific matches.
Review cisco routers forward packets based on the longest prefix match, selecting the route with the most specific subnet mask that matches the destination IP address., then practise related 200-301 questions on the same topic to reinforce the concept.
Cisco routers forward packets based on the longest prefix match, selecting the route with the most specific subnet mask that matches the destination IP address.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: May 17, 2026
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.