CCNA Network Infrastructure and Connectivity Practice Question
Which two statements accurately describe ARP in an IPv4 Ethernet network?
⚠ Common exam trap
Do not confuse ARP with routing protocols or assume it functions across routers. Remember, ARP is strictly for local address resolution.
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
✓
ARP resolves a known IPv4 address to a MAC address on the local segment.
ARP is the mechanism used to map a known IPv4 address to a Layer 2 MAC address on the local network segment. In plain language, if a device knows the IP address it wants to reach on the same LAN, ARP helps it discover the correct Ethernet destination MAC address to use in the frame. That is why ARP is so important for local delivery in IPv4 Ethernet environments. Without it, devices would know where they want to send traffic logically, but not how to address the actual frame on the local link. ARP does not cross routers in the usual way, and it is not a routing protocol. It does not determine best paths to remote networks. It simply helps with local resolution of IPv4-to-MAC information. This distinction matters a lot on CCNA questions because many wrong answers try to blur the line between local neighbor resolution and routing behavior.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
ARP resolves a known IPv4 address to a MAC address on the local segment.
Why this is correct
ARP operates at the boundary of Layer 2 and Layer 3 on a local Ethernet segment, mapping a known IPv4 address to its corresponding MAC address. This mapping is essential because Ethernet frames require a destination MAC for delivery, while upper-layer applications only provide IP addresses. The ARP cache stores these resolved mappings to avoid repeating the request for every traffic flow.
- ✗
ARP is used to choose the best Layer 3 path across multiple routers.
Why it's wrong here
Selecting the best Layer 3 path across multiple routers is accomplished by dynamic routing protocols like OSPF or EIGRP, or by static routes, which compare metric values such as bandwidth or delay. ARP has no concept of routing metrics or path costs; it simply maps a next-hop IP address to a MAC address on a directly connected link. Its scope is local link resolution, not internetwork path selection.
When this WOULD be correct
If the question were to ask about protocols that facilitate routing decisions or path selection in a multi-router environment, such as OSPF or EIGRP, then option B could be correct in that context, as those protocols do indeed choose the best Layer 3 path.
- ✓
ARP requests are typically sent as broadcasts on the local LAN.
Why this is correct
An ARP request is encapsulated in an Ethernet broadcast frame with destination MAC FF:FF:FF:FF:FF:FF, ensuring every host on the broadcast domain receives it. Only the host whose IPv4 address matches the target IP responds with a unicast ARP reply containing its MAC address. Because Layer 2 broadcasts are never forwarded by routers, this mechanism remains confined to the local LAN segment.
- ✗
ARP can normally resolve the MAC address of a host located across a routed network.
Why it's wrong here
ARP is a link-local protocol that operates only within the sender's own broadcast domain, so it cannot resolve a MAC address for a host on a different subnet. When a host needs to send to a remote IP, it instead sends an ARP request for the default gateway's IP, delivering the packet to the router. The router then independently resolves the next hop toward the destination; the remote host's MAC is never learned by the original sender.
When this WOULD be correct
If the exam question were to ask about a protocol that can resolve MAC addresses across routed networks, such as when discussing proxy ARP or specific configurations involving ARP in a multi-layer switch environment, then this option would be correct.
- ✗
ARP replaces the need for a default gateway.
Why it's wrong here
The default gateway is a Layer 3 forwarding rule that tells the host where to send packets destined for remote subnets, while ARP merely provides name resolution from IP to MAC address. Without a configured default gateway, a host cannot know which router to use for off-subnet traffic, even if it can perfectly resolve local MAC addresses. Thus, ARP does not replace gateway logic; it only helps find the gateway's MAC after the gateway has been selected.
When this WOULD be correct
In a question focused on network configuration or design where the context is a flat network without any routing, one might ask if ARP can eliminate the need for a default gateway. In such a scenario, if the question specifies that all devices are on the same subnet, the answer could be considered correct.
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.
✓ARP resolves a known IPv4 address to a MAC address on the local segment.Correct answer▾
Why this is correct
ARP operates at the boundary of Layer 2 and Layer 3 on a local Ethernet segment, mapping a known IPv4 address to its corresponding MAC address. This mapping is essential because Ethernet frames require a destination MAC for delivery, while upper-layer applications only provide IP addresses. The ARP cache stores these resolved mappings to avoid repeating the request for every traffic flow.
✗ARP is used to choose the best Layer 3 path across multiple routers.Wrong answer — click to see why▾
Why this is wrong here
ARP operates at Layer 2 and is only concerned with resolving IP addresses to MAC addresses on the local link. Path selection between routers is performed by routing protocols (e.g., OSPF, EIGRP) and the routing table, which operate at Layer 3.
★ When this WOULD be the correct answer
If the question were to ask about protocols that facilitate routing decisions or path selection in a multi-router environment, such as OSPF or EIGRP, then option B could be correct in that context, as those protocols do indeed choose the best Layer 3 path.
Why candidates choose this
Students may confuse ARP with routing because both involve IP addresses. However, ARP is strictly for local MAC resolution, not for determining the best path across multiple routers.
✗ARP can normally resolve the MAC address of a host located across a routed network.Wrong answer — click to see why▾
Why this is wrong here
ARP requests are broadcast only within the local subnet and are not forwarded by routers. To reach a host on a different subnet, the source host must send the packet to its default gateway, which then uses its own ARP process to resolve the next-hop MAC.
★ When this WOULD be the correct answer
If the exam question were to ask about a protocol that can resolve MAC addresses across routed networks, such as when discussing proxy ARP or specific configurations involving ARP in a multi-layer switch environment, then this option would be correct.
Why candidates choose this
A student might think ARP can resolve any IP address because ARP tables can contain entries for remote hosts learned via proxy ARP, but proxy ARP is a special case and not the normal operation. Typically, ARP is limited to the local link.
✗ARP replaces the need for a default gateway.Wrong answer — click to see why▾
Why this is wrong here
ARP does not replace the default gateway; it only resolves the MAC address of the gateway or other local hosts. The default gateway is still required for routing traffic to other subnets, as ARP cannot provide Layer 3 forwarding.
★ When this WOULD be the correct answer
In a question focused on network configuration or design where the context is a flat network without any routing, one might ask if ARP can eliminate the need for a default gateway. In such a scenario, if the question specifies that all devices are on the same subnet, the answer could be considered correct.
Why candidates choose this
Since ARP is used to find the MAC address of the default gateway, some might think it eliminates the need for a gateway. However, the gateway's IP address must still be configured, and ARP only provides the MAC for that IP.
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
Routing Protocol Comparison
| Protocol | Metric | Max Hops | Algorithm | Type |
|---|---|---|---|---|
| RIP v2 | Hop count | 15 | Bellman-Ford | Distance vector |
| OSPF | Cost (bandwidth) | Unlimited | Dijkstra (SPF) | Link state |
| EIGRP | Composite metric | Unlimited | DUAL | Hybrid |
| IS-IS | Cost | Unlimited | Dijkstra | Link state |
| BGP | Policy / attributes | Unlimited | Path vector | Path vector |
RIP's 15-hop limit makes it unsuitable for large networks. OSPF and EIGRP dominate modern enterprise deployments.
Go deeper
Related to this question
Learn chapter
IPv4 Addressing and Address Classes
Key term
Intermediate System to Intermediate System
A routing protocol used within large enterprise networks to exchange routing information between routers, helping data find the best path across the network.
Key term
Ethernet
Ethernet is a wired networking technology that connects devices like computers, printers, and servers to each other and to the internet using cables.
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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.