- A
It forwards packets destined for networks other than the local subnet
Correct. The default gateway provides a route to remote networks.
- B
It resolves domain names to IP addresses
Why wrong: That is the function of a DNS server, not a default gateway.
- C
It assigns IP addresses to devices on the local network
Why wrong: IP address assignment is typically done by a DHCP server.
- D
It filters traffic based on MAC addresses
Why wrong: Filtering based on MAC addresses is typically done by switches with port security, not the default gateway.
Question 488 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 best describes the function of a default gateway on a host?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"best"Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
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 packets destined for networks other than the local subnet
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 subnet. When a host determines that the destination IP is not reachable via ARP on the local link, it forwards the packet to the default gateway's MAC address, which then routes the packet toward the remote network. This is essential for inter-subnet communication in any IP network.
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 forwards packets destined for networks other than the local subnet
Why this is correct
Correct. The default gateway provides a route to remote networks.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
It resolves domain names to IP addresses
Why it's wrong here
That is the function of a DNS server, not a default gateway.
When this WOULD be correct
In a question asking 'Which service translates domain names to IP addresses?', the correct answer would be 'DNS server' or 'Name resolution service'.
- ✗
It assigns IP addresses to devices on the local network
- ✗
It filters traffic based on MAC addresses
Why it's wrong here
Filtering based on MAC addresses is typically done by switches with port security, not the default gateway.
When this WOULD be correct
In a question asking 'Which device filters traffic based on MAC addresses to control network access?', the correct answer would be a switch with port security or a MAC filter, not a default gateway.
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 packets destined for networks other than the local subnetCorrect answer▾
Why this is correct
Correct. The default gateway provides a route to remote networks.
✗It resolves domain names to IP addressesWrong answer — click to see why▾
Why this is wrong here
The default gateway is responsible for routing packets to destinations outside the local subnet, not for resolving domain names to IP addresses. DNS servers perform name resolution.
★ When this WOULD be the correct answer
In a question asking 'Which service translates domain names to IP addresses?', the correct answer would be 'DNS server' or 'Name resolution service'.
Why candidates choose this
Candidates may confuse the default gateway with DNS because both are essential for internet connectivity and are often configured together in network settings.
✗It assigns IP addresses to devices on the local networkWrong answer — click to see why▾
Why this is wrong here
The default gateway does not assign IP addresses; that is the function of a DHCP server. The default gateway is a router that forwards packets to destinations outside the local subnet.
★ When this WOULD be the correct answer
In a question asking 'Which service dynamically assigns IP addresses to devices on a network?', the correct answer would be 'DHCP server' (option C if rephrased).
Why candidates choose this
Candidates may confuse the default gateway with a DHCP server because both are often configured on the same device (e.g., a home router) and both are essential for network connectivity.
✗It filters traffic based on MAC addressesWrong answer — click to see why▾
Why this is wrong here
A default gateway forwards packets to other networks, not filter traffic based on MAC addresses; MAC filtering is a function of switches or security features, not the default gateway.
★ When this WOULD be the correct answer
In a question asking 'Which device filters traffic based on MAC addresses to control network access?', the correct answer would be a switch with port security or a MAC filter, not a default gateway.
Why candidates choose this
Candidates may confuse the default gateway's role in network traffic control with MAC-based filtering, especially if they think of gateways as security devices that inspect packets.
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 often confuse the default gateway with a DNS server or DHCP server, because in many home networks the same device (the router) performs all three roles, but the exam tests the distinct Layer 3 routing function of the default gateway in isolation.
Detailed technical explanation
How to think about this question
When a host sends a packet to a non-local destination, it performs a logical AND of its own subnet mask with the destination IP; if the result differs from its own network address, it knows the destination is remote. The host then uses ARP to resolve the default gateway's IP to its MAC address, encapsulates the IP packet in an Ethernet frame with that MAC, and sends it to the gateway. In IPv6, the equivalent is the default router via Neighbor Discovery Protocol (NDP), and the host's routing table entry for ::/0 points to the default gateway.
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
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 |
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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Networking Concepts — study guide chapter
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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 packets destined for networks other than the local subnet — 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 subnet. When a host determines that the destination IP is not reachable via ARP on the local link, it forwards the packet to the default gateway's MAC address, which then routes the packet toward the remote network. This is essential for inter-subnet communication in any IP network.
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.
Are there clue words in this question I should notice?
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
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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