CCNA IP Routing Practice Question
Which three of the following statements about the routing table lookup process on a Cisco router are true? (Choose three.)
⚠ Common exam trap
Cisco often tests the misconception that an exact match overrides a more specific route, but the longest prefix match rule always selects the route with the longest subnet mask, regardless of administrative distance or metric.
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 router performs a longest prefix match to select the most specific route for a destination IP.
The routing table uses longest prefix match (A) to find the most specific route. The default route (C) is used only when no other route matches. Directly connected routes (F) are automatically installed when the interface is up/up. Option D is incorrect because the router does recursively resolve the next‑hop IP when it is not directly connected.
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 router performs a longest prefix match to select the most specific route for a destination IP.
Why this is correct
When a router receives a packet, it examines the destination IP address and searches its routing table for the route with the longest prefix length, meaning the highest number of matching bits in the network portion. This ensures that the most specific route, such as a /24, is chosen over a less specific one, like a /16, even if both entries could theoretically match. The longest prefix match algorithm is fundamental to IP routing because it enables precise path selection in networks with overlapping routes.
- ✗
If an exact match is found for the destination network, the router will forward the packet regardless of any more specific routes.
Why it's wrong here
This statement is false because the router does not prioritize a route based on whether it matches the destination network exactly; instead, it selects the route with the longest prefix length. Even if a route like 192.168.1.0/24 exactly matches the classful network of the destination, a more specific route such as 192.168.1.128/25 will be preferred for the matching portion of the address space. Therefore, the presence of a more specific route always overrides a less specific exact network match.
- ✓
A default route (0.0.0.0/0) is used only when no other route matches the destination IP.
Why this is correct
The default route, also known as the quad-zero route, has a prefix length of /0, meaning it matches every possible IP address but is the least specific route. Because of the longest prefix match rule, the router will only use the default route if there is no other route in the routing table with a longer prefix that matches the destination. This makes it a catch-all route typically used to send traffic to an upstream provider or Internet gateway when a more specific path is unknown.
- ✗
The router does not perform recursive resolution when the next-hop IP address is not directly connected.
Why it's wrong here
This statement is false. When the next-hop IP address is not on a directly connected network, the router must perform a recursive lookup: it must first find a route to that next-hop address, then resolve that route to an exit interface and possibly an even more direct next-hop. This recursive resolution process is essential for routes learned via dynamic routing protocols, where the next hop may be several hops away. Without recursive resolution, the router would have no way to forward packets to an indirectly connected next hop, so the statement is incorrect.
- ✗
The router always prefers routes with a higher administrative distance over those with a lower administrative distance.
Why it's wrong here
This is the opposite of Cisco's actual behavior. Administrative distance (AD) is a measure of route trustworthiness; lower AD values are preferred because they indicate a more reliable source of routing information. For example, a directly connected route has an AD of 0, while a static route has an AD of 1, and OSPF has an AD of 110. If the router has multiple routes to the same destination from different protocols, it will select the route with the lowest AD. The statement's claim that higher AD is preferred is factually incorrect regarding standard Cisco IOS operation.
- ✓
A directly connected route is automatically installed in the routing table when an interface is configured with an IP address and is up/up.
Why this is correct
When a router interface is configured with an IP address and the line protocol is up (both physical and data-link layers are operational), the router automatically installs a route to the directly connected network in its routing table. This route has an administrative distance of 0 and is marked with the C code, indicating a directly connected network. No dynamic routing protocol or static route is needed for this route to appear, as it is derived from the interface configuration and the link state. If the interface goes down, the corresponding route is removed from the routing table.
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 router performs a longest prefix match to select the most specific route for a destination IP.Correct answer▾
Why this is correct
When a router receives a packet, it examines the destination IP address and searches its routing table for the route with the longest prefix length, meaning the highest number of matching bits in the network portion. This ensures that the most specific route, such as a /24, is chosen over a less specific one, like a /16, even if both entries could theoretically match. The longest prefix match algorithm is fundamental to IP routing because it enables precise path selection in networks with overlapping routes.
✗The router does not perform recursive resolution when the next-hop IP address is not directly connected.Wrong answer — click to see why▾
Why this is wrong here
When the next-hop IP is not directly connected, the router does recursively resolve the address to determine the outgoing interface.
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?”
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Interpreting HSRP and VRRP Operational Status
Key term
Routing table
A routing table is a data set stored in a router or host that contains information about network paths and is used to determine where to forward data packets.
Key term
Interface
An interface is a point of connection or interaction between two systems, devices, or software components that allows them to exchange information or signals.
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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.