CCNA Network Services and Security Practice Question
Which two statements accurately describe DNS and DHCP?
⚠ Common exam trap
A frequent exam trap is confusing DHCP with NAT or assuming DHCP replaces the need for subnet masks and default gateways. Some candidates mistakenly believe DHCP translates private IP addresses to public ones, but this is the role of NAT, not DHCP. Additionally, DHCP does not remove the need for subnet masks or default gateways; instead, it provides these parameters automatically to clients. Misunderstanding these distinctions can lead to incorrect answers, especially when questions ask about the functions of IP services. Carefully distinguishing DHCP’s role in dynamic addressing from NAT’s role in address translation is essential to avoid this trap.
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
✓
DNS resolves names to IP information, while DHCP dynamically assigns addressing information to clients.
DNS and DHCP solve very different problems, even though both are common infrastructure services. DNS helps devices and users find systems by name. In simple terms, it means people can type a hostname rather than memorizing numeric IP addresses. DHCP automatically gives clients important IP settings such as an address, subnet mask, default gateway, and often DNS server information. The trick in comparison questions is not to blend their roles together. DHCP does not perform NAT, and it does not eliminate the need for addressing details; it actually supplies them.
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 resolves names to IP information, while DHCP dynamically assigns addressing information to clients.
Why this is correct
DNS is an application-layer protocol that translates human-friendly domain names into the numeric IP addresses used for routing and identifying hosts. DHCP, on the other hand, is a network management protocol that dynamically allocates IP addresses and other network parameters such as subnet mask, default gateway, and DNS server addresses to clients when they join a network. Thus, DNS resolves names to IPs, while DHCP automates the assignment of addressing information, fulfilling two distinct but complementary roles in network connectivity.
- ✗
DHCP is used primarily to translate private addresses into public addresses.
Why it's wrong here
DHCP is not designed for address translation between private and public address spaces; that function belongs to Network Address Translation (NAT), typically implemented on routers or firewalls. DHCP's role is limited to dynamically assigning IP configuration—such as IP address, subnet mask, default gateway, and DNS servers—to hosts within a local network. While DHCP may work alongside NAT in many enterprise environments, conflating the two misidentifies their distinct purposes, as DHCP does not modify or translate IP headers.
When this WOULD be correct
If the exam question asked about protocols that manage address translation in a network, specifically focusing on how private IP addresses are converted to public addresses for internet access, then this option would be correct in that context.
- ✓
DNS can help users reach services by hostname instead of remembering numeric IP addresses.
Why this is correct
One of the primary benefits of DNS is usability: it allows users to reach network services by entering an easily remembered hostname like 'www.example.com' instead of memorizing a dotted-decimal or IPv6 numeric address. The DNS hierarchy consists of a distributed database that maps names to addresses, enabling clients to resolve those names into the IP information needed to initiate a connection. This abstraction reduces human error and makes the internet far more user-friendly, as it would be impractical to remember the IP address of every website or service we use.
- ✗
DHCP replaces the need for subnet masks and default gateways.
Why it's wrong here
DHCP does not eliminate the need for subnet masks and default gateways; rather, it automates the delivery of these essential parameters to clients. A subnet mask is still required to determine the network and host portions of an IP address, and a default gateway is essential for routing traffic outside the local subnet. Without these values, a client would be unable to determine which destinations are local or how to reach remote networks—DHCP simply distributes them automatically, saving administrators from manual configuration and reducing errors.
When this WOULD be correct
In a question that asks about technologies that eliminate the need for traditional network configuration methods, such as static IP addressing, this option could be correct if it implies that DHCP automates configuration, thus reducing manual entry of subnet masks and gateways.
- ✗
DNS and DHCP are both Layer 1 technologies.
Why it's wrong here
DNS and DHCP operate at the application layer (Layer 7) of the OSI model, not at Layer 1. Layer 1 is the physical layer, which involves the transmission and reception of raw bit streams over physical media like cables, fiber, or radio waves. In contrast, DNS and DHCP use higher-layer protocols—DNS primarily uses UDP port 53 or TCP port 53, while DHCP uses UDP ports 67 and 68—and depend on Layer 3 (IP) and Layer 4 (UDP/TCP) services for their operation, making them clearly not Layer 1 technologies.
When this WOULD be correct
In a question that asks which technologies operate at Layer 1, if the context is expanded to include only Layer 1 devices or protocols, one might mistakenly categorize DHCP and DNS as Layer 1 technologies due to their reliance on physical network infrastructure for communication.
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.
✓DNS resolves names to IP information, while DHCP dynamically assigns addressing information to clients.Correct answer▾
Why this is correct
DNS is an application-layer protocol that translates human-friendly domain names into the numeric IP addresses used for routing and identifying hosts. DHCP, on the other hand, is a network management protocol that dynamically allocates IP addresses and other network parameters such as subnet mask, default gateway, and DNS server addresses to clients when they join a network. Thus, DNS resolves names to IPs, while DHCP automates the assignment of addressing information, fulfilling two distinct but complementary roles in network connectivity.
✗DHCP is used primarily to translate private addresses into public addresses.Wrong answer — click to see why▾
Why this is wrong here
DHCP is responsible for dynamically assigning IP addresses and other network configuration parameters to clients, not for translating private addresses to public addresses. Address translation is performed by Network Address Translation (NAT), typically on routers or firewalls.
★ When this WOULD be the correct answer
If the exam question asked about protocols that manage address translation in a network, specifically focusing on how private IP addresses are converted to public addresses for internet access, then this option would be correct in that context.
Why candidates choose this
Students may confuse DHCP with NAT because both involve IP address management and are often used together in networks. The term 'translate' might be loosely associated with DHCP's role in assigning addresses, leading to this misconception.
✗DHCP replaces the need for subnet masks and default gateways.Wrong answer — click to see why▾
Why this is wrong here
DHCP does not replace the need for subnet masks and default gateways; rather, it typically provides these parameters to clients automatically. Devices still require subnet masks to determine network boundaries and default gateways to reach remote networks.
★ When this WOULD be the correct answer
In a question that asks about technologies that eliminate the need for traditional network configuration methods, such as static IP addressing, this option could be correct if it implies that DHCP automates configuration, thus reducing manual entry of subnet masks and gateways.
Why candidates choose this
Because DHCP automates the assignment of these parameters, some may incorrectly think it eliminates the need for them altogether. However, the parameters are still essential for network communication; DHCP just delivers them dynamically.
✗DNS and DHCP are both Layer 1 technologies.Wrong answer — click to see why▾
Why this is wrong here
DNS and DHCP operate at the Application Layer (Layer 7) of the OSI model, not Layer 1 (Physical Layer). They use underlying transport protocols (UDP/TCP) and rely on lower layers for data transmission.
★ When this WOULD be the correct answer
In a question that asks which technologies operate at Layer 1, if the context is expanded to include only Layer 1 devices or protocols, one might mistakenly categorize DHCP and DNS as Layer 1 technologies due to their reliance on physical network infrastructure for communication.
Why candidates choose this
Students might mistakenly think that because DNS and DHCP are fundamental network services, they belong to lower layers. Additionally, the term 'Layer 1' might be confused with 'Layer 2' or 'Layer 3' due to incomplete understanding of the OSI model.
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
OSI Model Reference
| Layer | Name | PDU | Key Protocols / Devices |
|---|---|---|---|
| 7 | Application | Data | HTTP, HTTPS, DNS, SMTP, FTP, SSH |
| 6 | Presentation | Data | TLS / SSL, JPEG, ASCII encoding |
| 5 | Session | Data | NetBIOS, RPC, SIP |
| 4 | Transport | Segment / Datagram | TCP, UDP |
| 3 | Network | Packet | IP, ICMP, OSPF — Routers |
| 2 | Data Link | Frame | Ethernet, Wi-Fi, PPP — Switches, Bridges |
| 1 | Physical | Bits | Cables, NICs, Hubs, Repeaters |
Go deeper
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Key term
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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.