200-901 Network Fundamentals Practice Question
An application needs to discover the MAC address of another device on the same local network. Which protocol does it use?
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
ARP (Address Resolution Protocol) is used to map an IP address to a MAC address on a local network.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
DNS
Why it's wrong here
DNS resolves hostnames to IP addresses and carries no MAC address information, so it cannot answer the query. It is tempting because it is the standard name-resolution protocol, and it would be correct for mapping a hostname to an IPv4 or IPv6 address, but link-layer address resolution on the local segment requires ARP.
- ✗
ICMP
Why it's wrong here
ICMP reports reachability and errors; its echo request and reply exchange never carries a MAC address. It is tempting because ping confirms whether a host is alive, and it would be correct for testing connectivity or path reachability, but obtaining the hardware address of a same-subnet device requires an ARP request.
- ✓
ARP
Why this is correct
ARP broadcasts a request containing the target IPv4 address, and the owning device replies with its MAC address. This resolves layer-3 to layer-2 addressing within the same broadcast domain, which is exactly what the application needs.
- ✗
DHCP
Why it's wrong here
DHCP assigns IP addresses and options to clients; it does not resolve an existing device's MAC address on demand. It is tempting because DHCP bindings do associate addresses with hardware identifiers, and it would be correct for leasing configuration to a new host, but querying a known peer's MAC requires ARP.
Quick reference
Access Control Model Comparison
| Model | Acronym | Who Controls Access? | Best For |
|---|---|---|---|
| Discretionary Access Control | DAC | Resource owner | Small teams, file shares |
| Mandatory Access Control | MAC | System / security labels | Classified govt / military |
| Role-Based Access Control | RBAC | Administrator (via roles) | Enterprise environments |
| Attribute-Based Access Control | ABAC | Policy engine (user + resource attributes) | Fine-grained, dynamic policies |
| Rule-Based Access Control | RuBAC | System rules / ACLs | Firewall rules, network ACLs |
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-901 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 200-901 exam.