- A
It translates domain names to IP addresses
Why wrong: This is the function of a DNS server, not the default gateway.
- B
It assigns IP addresses to devices on the network
Why wrong: IP address assignment is performed by a DHCP server, not by the default gateway.
- C
It forwards traffic from the local network to other networks
The default gateway is the router that sends packets destined for non-local networks to the appropriate path.
- D
It filters traffic to prevent unauthorized access
Why wrong: Filtering and security are performed by firewalls or access control lists, not the default gateway's primary purpose.
Question 255 of 520
N10-009 Networking Concepts Practice Question
This N10-009 practice question tests your understanding of networking concepts. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 describes the purpose of a default gateway on a host in a TCP/IP network?
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
✓
It forwards traffic from the local network to other networks
The default gateway is the router interface on the local subnet that a host uses to send packets destined for IP addresses outside its own network. When a host determines that the destination IP is not in its local subnet (via its subnet mask), it forwards the frame to the default gateway's MAC address, which then routes the packet toward the remote network. Without a default gateway, a host can only communicate with devices on the same local broadcast domain.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
It translates domain names to IP addresses
Why it's wrong here
This is the function of a DNS server, not the default gateway.
When this WOULD be correct
In a question asking 'Which service translates domain names to IP addresses?', option A would be correct, as DNS performs this function.
- ✗
It assigns IP addresses to devices on the network
Why it's wrong here
IP address assignment is performed by a DHCP server, not by the default gateway.
When this WOULD be correct
In a question asking 'Which network service dynamically assigns IP addresses to devices on a network?', the correct answer would be 'DHCP server' or a similar option describing IP address assignment.
- ✓
It forwards traffic from the local network to other networks
Why this is correct
The default gateway is the router that sends packets destined for non-local networks to the appropriate path.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
It filters traffic to prevent unauthorized access
Why it's wrong here
Filtering and security are performed by firewalls or access control lists, not the default gateway's primary purpose.
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 N10-009 exam frequently reuses these exact scenarios with slightly different constraints.
✓It forwards traffic from the local network to other networksCorrect answer▾
Why this is correct
The default gateway is the router that sends packets destined for non-local networks to the appropriate path.
✗It translates domain names to IP addressesWrong answer — click to see why▾
Why this is wrong here
A default gateway forwards traffic to other networks, not translates domain names to IP addresses; that is the function of DNS.
★ When this WOULD be the correct answer
In a question asking 'Which service translates domain names to IP addresses?', option A would be correct, as DNS performs this function.
Why candidates choose this
Candidates may confuse the default gateway with DNS because both involve network connectivity and are often configured together, leading to a mix-up of their roles.
✗It assigns IP addresses to devices on the networkWrong answer — click to see why▾
Why this is wrong here
A default gateway forwards traffic to other networks, not assign IP addresses. IP address assignment is typically done by a DHCP server, not a default gateway.
★ When this WOULD be the correct answer
In a question asking 'Which network service dynamically assigns IP addresses to devices on a network?', the correct answer would be 'DHCP server' or a similar option describing IP address assignment.
Why candidates choose this
Candidates may confuse the default gateway with a DHCP server because both are common network services, and the gateway often runs a DHCP server in small networks.
✗It filters traffic to prevent unauthorized accessWrong answer — click to see why▾
Why this is wrong here
A default gateway forwards traffic to other networks, not filters it. Traffic filtering to prevent unauthorized access is the function of a firewall, not a default gateway.
★ When this WOULD be the correct answer
This option would be correct in a question asking: 'Which of the following describes the purpose of a firewall on a host in a TCP/IP network?'
Why candidates choose this
Candidates may confuse the default gateway with a firewall because both are involved in network traffic control and security, leading them to think the gateway filters traffic.
Analysis generated from the official N10-009blueprint 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
The trap here is that candidates confuse the default gateway with a DNS server or DHCP server, because all three are often configured on the same router in small networks, but the exam specifically tests the Layer 3 forwarding role of the default gateway.
Detailed technical explanation
How to think about this question
When a host sends a packet, it performs a logical AND between its own IP and subnet mask, and the destination IP and subnet mask; if the results differ, the host knows the destination is remote and sends the packet to the default gateway's MAC address (obtained via ARP). In IPv6, the default gateway is often learned through Router Advertisement (RA) messages using Neighbor Discovery Protocol (NDP), and a host can have multiple default gateways with different metrics for redundancy. A real-world scenario: if the default gateway is misconfigured or down, users can still access local resources (printers, file shares) but cannot reach the internet or other subnets.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
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
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A network engineer segments a warehouse floor into three subnets: 20 scanners, 5 printers, and 2 management hosts. Picking the wrong mask wastes addresses or leaves too few usable hosts. Exam questions test whether you can apply CIDR notation, calculate block size, and identify the correct usable-host range for a given prefix.
Visual reference
Quick reference
IPv4 Address Class Summary
| Class | First Octet Range | Default Mask | Networks | Hosts per Network |
|---|---|---|---|---|
| A | 1–126 | /8 (255.0.0.0) | 126 | 16,777,214 |
| B | 128–191 | /16 (255.255.0.0) | 16,384 | 65,534 |
| C | 192–223 | /24 (255.255.255.0) | 2,097,152 | 254 |
| D | 224–239 | N/A | Multicast groups | — |
| E | 240–255 | N/A | Reserved / experimental | — |
127.x.x.x is reserved for loopback. Modern networks use CIDR (classless) rather than classful addressing.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Questions learners often ask
What does this N10-009 question test?
Networking Concepts — This question tests Networking Concepts — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: It forwards traffic from the local network to other networks — The default gateway is the router interface on the local subnet that a host uses to send packets destined for IP addresses outside its own network. When a host determines that the destination IP is not in its local subnet (via its subnet mask), it forwards the frame to the default gateway's MAC address, which then routes the packet toward the remote network. Without a default gateway, a host can only communicate with devices on the same local broadcast domain.
What should I do if I get this N10-009 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
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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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