The answer is that a host uses ARP to resolve the IPv4 address of its default gateway to a MAC address when sending traffic to a remote network. This is correct because on an Ethernet LAN, every frame requires a destination MAC address for the switch to forward it at Layer 2. When a host needs to reach a destination outside its own subnet, it cannot use that remote host’s MAC address directly; instead, it must send the frame to its default gateway (the router), so it performs an ARP request for the gateway’s IP to obtain the corresponding MAC. On the CCNA 200-301 v2 exam, this concept tests your understanding of how Layer 2 and Layer 3 interact—a common trap is assuming the host ARPs for the remote destination’s MAC, which is impossible across a router. A helpful memory tip: “Remote net? ARP the gateway—don’t chase what you can’t reach.”
CCNA Network Infrastructure and Connectivity Practice Question
This 200-301 practice question tests your understanding of network infrastructure and connectivity. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. A key principle to apply: aRP resolves an IPv4 address to a MAC address to enable Layer 2 frame forwarding on Ethernet LANs.. 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.
A support engineer is explaining why a host uses ARP before sending a frame on an Ethernet LAN. Which two statements are correct?
DNS resolves names to IP addresses, not IPs to MACs.
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 an IPv4 address to a MAC addressCorrect answer▾
Why this is correct
The host needs the destination MAC for local Layer 2 forwarding.
✗ARP is used to discover the remote router's OSPF router IDWrong answer — click to see why▾
Why this is wrong here
ARP operates at Layer 2 and resolves IP addresses to MAC addresses; it has no involvement with OSPF or any routing protocol identifiers. OSPF router IDs are determined by configuration or router ID selection process, not ARP.
Why candidates choose this
Students may confuse ARP with protocols that discover network information, or mistakenly think ARP is used for neighbor discovery in routing protocols like OSPF.
✗ARP replaces DNS for hostname resolutionWrong answer — click to see why▾
Why this is wrong here
DNS resolves hostnames to IP addresses, while ARP resolves IP addresses to MAC addresses. They serve different purposes and operate at different layers; ARP does not replace DNS.
Why candidates choose this
Both ARP and DNS involve resolution of one identifier to another, leading some to incorrectly think ARP can resolve hostnames.
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
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is selecting options that confuse ARP with DNS or routing protocol functions. For example, some may incorrectly believe ARP resolves hostnames like DNS or discovers OSPF router IDs. These misunderstandings arise because ARP and DNS both involve address resolution, but ARP only maps IPv4 addresses to MAC addresses on the local LAN, while DNS maps hostnames to IP addresses. Similarly, ARP does not interact with routing protocols like OSPF. Misinterpreting ARP’s role leads to incorrect answers and can cost points on the CCNA exam.
Detailed technical explanation
How to think about this question
Address Resolution Protocol (ARP) is a fundamental protocol used in IPv4 networking to map a known IP address to a MAC address on a local Ethernet LAN. When a host wants to send a frame to another device on the same subnet, it must encapsulate the packet in a Layer 2 frame addressed to the destination's MAC address. Since IP addresses operate at Layer 3 and MAC addresses at Layer 2, ARP resolves this mismatch by broadcasting a request to discover the MAC address corresponding to the target IPv4 address.
When a host needs to send a packet to a remote network, it cannot directly reach the destination MAC address because the destination is outside the local subnet. Instead, the host sends the frame to its default gateway's MAC address. To do this, the host uses ARP to resolve the default gateway's IPv4 address to its MAC address. This ensures that the frame is correctly forwarded to the router, which then routes the packet toward the remote destination. This behavior is critical in Cisco networks and is tested in the CCNA exam to verify understanding of Layer 2 and Layer 3 interactions.
A common exam trap is confusing ARP with other protocols or functions, such as DNS or routing protocol identifiers like OSPF router IDs. ARP strictly resolves IPv4 addresses to MAC addresses on the local network segment and does not perform hostname resolution or routing protocol discovery. Understanding this distinction helps avoid selecting incorrect answers that mention unrelated protocols or functions. In practical networking, ARP requests and replies are essential for efficient LAN communication and proper routing through gateways.
KKey Concepts to Remember
ARP resolves an IPv4 address to a MAC address to enable Layer 2 frame forwarding on Ethernet LANs.
A host uses ARP to find the MAC address of its default gateway when sending packets to remote networks.
Frames sent to remote destinations are addressed to the default gateway's MAC address for proper routing.
ARP operates by broadcasting requests on the local subnet and receiving unicast replies with MAC addresses.
ARP does not resolve hostnames or routing protocol identifiers; it strictly maps IP addresses to MAC addresses.
A host must have the destination MAC address before sending an Ethernet frame, regardless of the IP destination.
The default gateway’s MAC address is critical for off-subnet communication and is learned via ARP.
Confusing ARP with DNS or routing protocols leads to common exam mistakes about address resolution.
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.
Key takeaway
ARP resolves an IPv4 address to a MAC address to enable Layer 2 frame forwarding on Ethernet LANs.
Real-world example
How this comes up in practice
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 200-301 question in full detail.
Review aRP resolves an IPv4 address to a MAC address to enable Layer 2 frame forwarding on Ethernet LANs., then practise related 200-301 questions on the same topic to reinforce the concept.
Network Infrastructure and Connectivity — This question tests Network Infrastructure and Connectivity — ARP resolves an IPv4 address to a MAC address to enable Layer 2 frame forwarding on Ethernet LANs..
What is the correct answer to this question?
The correct answer is: ARP resolves an IPv4 address to a MAC address — On Ethernet, the sender needs a destination MAC address. For remote destinations, that usually means ARPing for the default gateway's MAC.
What should I do if I get this 200-301 question wrong?
Review aRP resolves an IPv4 address to a MAC address to enable Layer 2 frame forwarding on Ethernet LANs., then practise related 200-301 questions on the same topic to reinforce the concept.
What is the key concept behind this question?
ARP resolves an IPv4 address to a MAC address to enable Layer 2 frame forwarding on Ethernet LANs.
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