Question 414 of 520

Network Troubleshooting →easyMultiple ChoiceObjective-mapped

Quick Answer

The correct answer is that the DHCP server is unreachable. When a Windows or Linux client fails to obtain a DHCP lease, the operating system automatically assigns an APIPA address from the 169.254.0.0/16 range, as defined by RFC 3927. This self-assigned IP, like 169.254.15.77, allows local link-only communication but blocks internet access because no default gateway is configured. On the CompTIA Network+ N10-009 exam, this scenario tests your understanding of DHCP failure symptoms and the APIPA fallback mechanism. A common trap is confusing APIPA with a static IP misconfiguration—remember that APIPA addresses always start with 169.254, not 192.168 or 10.x. For a quick memory tip, think “169.254 = No Server” to recall that this address range means the DHCP server was never reached.

N10-009 Network Troubleshooting Practice Question

This N10-009 practice question tests your understanding of network troubleshooting. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.

A user reports that they cannot access the internet. The network technician checks the workstation's IP configuration and finds the IP address 169.254.15.77. What does this address indicate?

Question 1easymultiple choice

Full question →

A
The workstation has a static IP address configured.
Why wrong: APIPA addresses are automatically assigned only when DHCP fails. A static IP would be manually configured and would typically not be in the 169.254.x.x range.
B
The DHCP server is unreachable.
APIPA is used when a DHCP server is not available. The workstation cannot obtain a proper IP address, so it self-assigns an APIPA address. This prevents internet access because APIPA addresses are not routable.
C
The DNS server is down.
Why wrong: A DNS issue would prevent name resolution but the workstation would still have a valid IP address from DHCP. APIPA addresses point to a DHCP failure, not DNS.
D
The default gateway is misconfigured.
Why wrong: A misconfigured default gateway could still allow the device to obtain a DHCP address. APIPA indicates the device could not get an IP at all, so the issue is with DHCP, not the gateway.

Full breakdown with real-world context →

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

✓

The DHCP server is unreachable.

The IP address 169.254.15.77 falls within the Automatic Private IP Addressing (APIPA) range (169.254.0.0/16, per RFC 3927). This address is automatically assigned by the operating system when a DHCP client fails to receive a lease from a DHCP server, indicating that the DHCP server is unreachable or not responding.

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.

✗
The workstation has a static IP address configured.
Why it's wrong here
APIPA addresses are automatically assigned only when DHCP fails. A static IP would be manually configured and would typically not be in the 169.254.x.x range.
✓
The DHCP server is unreachable.
Why this is correct
APIPA is used when a DHCP server is not available. The workstation cannot obtain a proper IP address, so it self-assigns an APIPA address. This prevents internet access because APIPA addresses are not routable.
Related concept
Read the scenario before looking for a memorised answer.
✗
The DNS server is down.
Why it's wrong here
A DNS issue would prevent name resolution but the workstation would still have a valid IP address from DHCP. APIPA addresses point to a DHCP failure, not DNS.
✗
The default gateway is misconfigured.
Why it's wrong here
A misconfigured default gateway could still allow the device to obtain a DHCP address. APIPA indicates the device could not get an IP at all, so the issue is with DHCP, not the gateway.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates often confuse APIPA with a DNS failure or gateway issue, but APIPA specifically indicates a DHCP lease failure, not a problem with higher-layer services like DNS or routing.

Detailed technical explanation

How to think about this question

APIPA uses a link-local address that is only valid for communication within the same subnet; the workstation performs a gratuitous ARP probe to ensure no other device uses the same address before assigning it. In real-world scenarios, this often occurs when the DHCP server is down, the network cable is unplugged, or the switch port is in a VLAN that lacks a DHCP relay, causing the DHCP discover broadcast to never reach the server.

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 practitioner preparing for the N10-009 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.

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?

Network Troubleshooting — This question tests Network Troubleshooting — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: The DHCP server is unreachable. — The IP address 169.254.15.77 falls within the Automatic Private IP Addressing (APIPA) range (169.254.0.0/16, per RFC 3927). This address is automatically assigned by the operating system when a DHCP client fails to receive a lease from a DHCP server, indicating that the DHCP server is unreachable or not responding.

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

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Same concept, more angles

3 more ways this is tested on N10-009

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. A user reports that they cannot access any network resources. The technician checks the IP configuration on the workstation and sees an IP address of 169.254.10.55 with a subnet mask of 255.255.0.0. Which of the following should the technician check NEXT?

easy

A.Configure a static IP address on the workstation
✓ B.Verify that the DHCP server is available and reachable
C.Check the DNS server configuration on the workstation
D.Replace the network cable

Why B: The IP address 169.254.10.55 with a subnet mask of 255.255.0.0 is an Automatic Private IP Addressing (APIPA) address, which Windows assigns when a DHCP server is unreachable. The next logical step is to verify that the DHCP server is available and reachable, as this directly addresses the root cause of the failed DHCP lease acquisition.

Variation 2. A user reports that they cannot access any network resources. The technician runs 'ipconfig' on the workstation and sees that the IP address is 169.254.23.45 with a subnet mask of 255.255.0.0. What is the most likely cause of this issue?

easy

A.The workstation's network cable is unplugged.
B.The DNS server is not responding.
✓ C.The DHCP server is unreachable or not functioning.
D.The workstation has been assigned a static IP address in the wrong subnet.

Why C: The IP address 169.254.23.45 with a subnet mask of 255.255.0.0 is an Automatic Private IP Addressing (APIPA) address, which is assigned by the operating system when a DHCP discovery attempt fails. This indicates that the workstation was unable to contact a DHCP server to obtain a valid IP configuration, making an unreachable or non-functioning DHCP server the most likely cause.

Variation 3. A user reports that they cannot access any network resources. The technician checks the IP configuration and sees that the workstation has an IP address of 169.254.1.5. What is the most likely cause?

medium

A.The DNS server is down
✓ B.The DHCP server is unavailable
C.The default gateway is incorrect
D.The subnet mask is mismatched

Why B: The IP address 169.254.1.5 is an Automatic Private IP Addressing (APIPA) address (169.254.0.0/16 range), which Windows assigns when a DHCP client fails to receive a lease from a DHCP server. Since the workstation cannot obtain a valid IP configuration, it cannot communicate with any network resources, confirming that the DHCP server is unavailable.

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