Quick Answer
The answer is DHCP, or Dynamic Host Configuration Protocol, which is the correct choice because it is purpose-built to automatically assign IP addresses to devices on a network while also providing the subnet mask and default gateway as part of a single lease offer. When a client sends a DHCP Discover broadcast, the server replies with an Offer containing these three critical parameters, enabling the device to communicate immediately without manual configuration. On the CompTIA Network+ N10-009 exam, this concept tests your understanding of network layer automation and often appears in questions contrasting DHCP with static IP assignment or other protocols like APIPA, which only assigns an address when DHCP fails. A common trap is confusing DHCP with DNS, but remember that DHCP gives you the address and the gateway, while DNS resolves names to addresses. To lock it in, think of the mnemonic “DHCP Delivers Home Configuration Parameters”—the IP, subnet mask, and default gateway are your device’s network home.
This N10-009 practice question tests your understanding of networking concepts. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. 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.
Which of the following protocols is used to automatically assign IP addresses to devices on a network and also provides the subnet mask and default gateway?
DNS
Why wrong: DNS translates domain names to IP addresses, not assign IPs.
DHCP
DHCP provides automatic IP configuration including subnet mask and default gateway.
ARP
Why wrong: ARP resolves IP addresses to MAC addresses on a local network.
ICMP
Why wrong: ICMP is used for error reporting and diagnostics like ping.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
DHCP
DHCP (Dynamic Host Configuration Protocol) is the correct answer because it is specifically designed to automatically assign IP addresses to devices on a network, along with essential configuration parameters such as the subnet mask and default gateway. When a DHCP client sends a discover message, the DHCP server responds with an offer that includes these details, allowing the client to fully participate in network communication without manual configuration.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
DNS
DHCP
Why this is correct
DHCP provides automatic IP configuration including subnet mask and default gateway.
Related concept
Read the scenario before looking for a memorised answer.
ARP
Why it's wrong here
ARP resolves IP addresses to MAC addresses on a local network.
ICMP
Why it's wrong here
ICMP is used for error reporting and diagnostics like ping.
Common exam traps
Cisco often tests the distinction between DHCP and DNS, where candidates mistakenly think DNS assigns IP addresses because it 'looks up' information, but DNS only resolves names, not addresses or subnet masks.
Detailed technical explanation
DHCP operates using a four-step process (DORA: Discover, Offer, Request, Acknowledge) as defined in RFC 2131. The DHCP server can also provide additional options like DNS server addresses, lease time, and domain name, making it a critical component for centralized network configuration management. In real-world scenarios, DHCP relay agents (RFC 3046) allow a single DHCP server to serve multiple subnets, which is essential in large enterprise networks.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
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FAQ
Networking Concepts — This question tests Networking Concepts — Read the scenario before looking for a memorised answer..
The correct answer is: DHCP — DHCP (Dynamic Host Configuration Protocol) is the correct answer because it is specifically designed to automatically assign IP addresses to devices on a network, along with essential configuration parameters such as the subnet mask and default gateway. When a DHCP client sends a discover message, the DHCP server responds with an offer that includes these details, allowing the client to fully participate in network communication without manual configuration.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Same concept, more angles
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which of the following protocols is used to automatically assign IP addresses to devices on a network?
easyWhy B: DHCP (Dynamic Host Configuration Protocol) is the correct answer because it is specifically designed to automatically assign IP addresses and other network configuration parameters (such as subnet mask, default gateway, and DNS servers) to devices on a network. When a client device connects, it sends a DHCP Discover broadcast, and the DHCP server responds with an Offer, followed by a Request and Acknowledgment (DORA process), enabling plug-and-play connectivity.
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Last reviewed: Jun 11, 2026
This N10-009 practice question is part of Courseiva's free CompTIA 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 N10-009 exam.
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