- A
It translates private IP addresses to public IP addresses.
Why wrong: This describes NAT, not the default gateway.
- B
It provides DHCP services to clients.
Why wrong: DHCP servers assign IP addresses; the default gateway may be a router but its primary function is routing.
- C
It routes packets from a local subnet to destinations on other networks.
This is the fundamental purpose of a default gateway.
- D
It performs DNS resolution for network clients.
Why wrong: DNS resolution is handled by DNS servers, not the default gateway.
Question 375 of 520
Default Gateway Function: The Next-Hop Router in IP Routing
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 best describes the function of a default gateway?
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 routes packets from a local subnet to destinations on other networks.
The default gateway is a router or Layer 3 device on a local subnet that serves as the next-hop IP address for packets destined to networks outside the local subnet. When a host determines that the destination IP is not on the same subnet (using its subnet mask), it forwards the packet to the default gateway's MAC address via ARP, which then routes the packet toward the remote network. Without a correctly configured default gateway, a host can only communicate within its own subnet.
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 private IP addresses to public IP addresses.
Why it's wrong here
This describes NAT, not the default gateway.
- ✗
It provides DHCP services to clients.
Why it's wrong here
DHCP servers assign IP addresses; the default gateway may be a router but its primary function is routing.
When this WOULD be correct
In a question asking 'Which network service automatically assigns IP addresses to clients?', option B (DHCP) would be correct. The question would focus on IP address allocation rather than routing between networks.
- ✓
It routes packets from a local subnet to destinations on other networks.
Why this is correct
This is the fundamental purpose of a default gateway.
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 performs DNS resolution for network clients.
Why it's wrong here
DNS resolution is handled by DNS servers, not the default gateway.
When this WOULD be correct
In a question asking 'Which protocol translates domain names to IP addresses?' or 'What service resolves hostnames to IP addresses?', DNS would be the correct answer.
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 routes packets from a local subnet to destinations on other networks.Correct answer▾
Why this is correct
This is the fundamental purpose of a default gateway.
✗It translates private IP addresses to public IP addresses.Wrong answer — click to see why▾
Why this is wrong here
The default gateway does not perform NAT; its primary role is to forward packets from a local subnet to other networks. NAT is typically handled by a router or firewall, not the default gateway itself.
★ When this WOULD be the correct answer
In a question asking 'Which device translates private IP addresses to public IP addresses for internet access?', the correct answer would be 'A router performing NAT' or 'A NAT gateway'.
Why candidates choose this
Candidates often confuse the default gateway with a NAT router because both are involved in internet connectivity, and many home routers combine both functions, leading to the misconception that the default gateway itself performs translation.
✗It provides DHCP services to clients.Wrong answer — click to see why▾
Why this is wrong here
The default gateway is a router that forwards traffic from a local subnet to other networks, not a DHCP server. DHCP services are provided by a DHCP server, which may be a separate device or integrated into a router, but that is not the function of a default gateway.
★ When this WOULD be the correct answer
In a question asking 'Which network service automatically assigns IP addresses to clients?', option B (DHCP) would be correct. The question would focus on IP address allocation rather than routing between networks.
Why candidates choose this
Candidates often confuse the default gateway with a router that also provides DHCP, as many home routers combine both functions. They may assume the default gateway's role includes DHCP because they are commonly implemented together.
✗It performs DNS resolution for network clients.Wrong answer — click to see why▾
Why this is wrong here
DNS resolution translates domain names to IP addresses, but it does not route packets or serve as a gateway for traffic leaving the local subnet.
★ When this WOULD be the correct answer
In a question asking 'Which protocol translates domain names to IP addresses?' or 'What service resolves hostnames to IP addresses?', DNS would be the correct answer.
Why candidates choose this
Candidates may confuse the default gateway's role in directing traffic with DNS's role in resolving names, especially since both are essential for internet connectivity.
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 N10-009 exam often tests the misconception that the default gateway performs NAT or DHCP, but the trap here is that candidates confuse the default gateway's routing role with other common router functions like NAT or DHCP services.
Detailed technical explanation
How to think about this question
Under the hood, when a host sends a packet to a remote network, it checks its routing table; if no specific route exists, it uses the default route (0.0.0.0/0) pointing to the default gateway. The host then performs an ARP request for the default gateway's IP to obtain its MAC address, encapsulating the packet in a frame destined for that MAC. In a real-world scenario, if the default gateway is misconfigured or unreachable, hosts can still communicate locally but will fail to reach the internet or other subnets, often resulting in 'Destination Host Unreachable' errors.
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 routes packets from a local subnet to destinations on other networks. — The default gateway is a router or Layer 3 device on a local subnet that serves as the next-hop IP address for packets destined to networks outside the local subnet. When a host determines that the destination IP is not on the same subnet (using its subnet mask), it forwards the packet to the default gateway's MAC address via ARP, which then routes the packet toward the remote network. Without a correctly configured default gateway, a host can only communicate within its own subnet.
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
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Last reviewed: Jun 11, 2026
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