Question 1easymulti select
Full question →easymulti selectObjective-mapped
A support engineer is explaining why a host uses ARP before sending a frame on an Ethernet LAN. Which two statements are correct?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
ARP resolves an IPv4 address to a MAC address
The host needs the destination MAC for local Layer 2 forwarding.
B
Best answer
A host may ARP for its default gateway when sending to a remote network
The frame is addressed to the local gateway MAC for off-subnet traffic.
C
Distractor review
ARP is used to discover the remote router's OSPF router ID
ARP is unrelated to routing protocol identifiers.
D
Distractor review
ARP replaces DNS for hostname resolution
DNS resolves names to IP addresses, not IPs to MACs.
Common exam trap
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.
Technical deep dive
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.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
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?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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