Question 144 of 1,020

Mobile Device Network Connectivity →hardMultiple ChoiceObjective-mapped

Smartphone Connected to Wi-Fi But No Internet: DNS Misconfiguration

This 220-1201 practice question tests your understanding of mobile device network connectivity. 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's smartphone can connect to a corporate Wi-Fi network but cannot access any internet sites. Other devices on the same network work fine. The smartphone shows it is connected with full signal. What is the most likely cause?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

A
The smartphone's DNS settings are misconfigured or pointing to a non-functional server.
Incorrect DNS prevents domain name resolution, so the device cannot reach internet sites even though it is connected to the network.
B
The corporate network is blocking the smartphone's MAC address.
Why wrong: MAC filtering would prevent connection entirely, not allow connection with no internet.
C
The smartphone's Wi-Fi adapter is faulty.
Why wrong: A faulty adapter would cause disconnections or inability to connect, not a stable connection with no internet.
D
The corporate proxy server is down.
Why wrong: If the proxy were down, all devices would be affected, not just this smartphone.

Full breakdown with real-world context →

Quick Answer

The answer is a DNS misconfiguration. When a smartphone is connected to Wi-Fi but has no internet, while other devices on the same network work fine, the issue is almost always device-specific rather than network-wide. DNS (Domain Name System) translates domain names into IP addresses; if the smartphone’s DNS settings are incorrect or pointing to a non-functional server, it can establish a local Wi-Fi connection and obtain an IP address, but it will fail to resolve website names, effectively blocking internet access. On the CompTIA A+ Core 1 220-1201 exam, this scenario tests your ability to differentiate between network-layer problems (like DHCP or gateway issues) and application-layer problems (like DNS). A common trap is to blame the router or ISP, but the clue is that other devices work—pinpointing a client-side DNS error. Memory tip: “DNS = Door Number Sign—if the sign is wrong, you can’t find the house.”

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 smartphone's DNS settings are misconfigured or pointing to a non-functional server.

The smartphone can connect to the Wi-Fi network (Layer 2 connectivity is fine) and other devices work, so the issue is specific to this device's higher-layer configuration. DNS resolution is required to translate domain names to IP addresses; if the smartphone's DNS settings point to a non-functional or incorrect server, it will fail to resolve any hostname, preventing internet access even though the network connection itself is active. This matches the symptom of being connected with full signal but unable to browse.

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 smartphone's DNS settings are misconfigured or pointing to a non-functional server.
Why this is correct
Incorrect DNS prevents domain name resolution, so the device cannot reach internet sites even though it is connected to the network.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The corporate network is blocking the smartphone's MAC address.
Why it's wrong here
MAC filtering would prevent connection entirely, not allow connection with no internet.
✗
The smartphone's Wi-Fi adapter is faulty.
Why it's wrong here
A faulty adapter would cause disconnections or inability to connect, not a stable connection with no internet.
✗
The corporate proxy server is down.
Why it's wrong here
If the proxy were down, all devices would be affected, not just this smartphone.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The 220-1201 exam often tests the distinction between Layer 2 connectivity (Wi-Fi association) and Layer 3/application-layer services (DNS, proxy), leading candidates to incorrectly blame the network infrastructure or hardware when the real problem is a device-specific configuration error.

Detailed technical explanation

How to think about this question

DNS resolution uses UDP port 53 by default, and misconfigured DNS can be verified by checking the device's network settings or using commands like `nslookup` or `dig` to test resolution against a known public DNS server (e.g., 8.8.8.8). In enterprise environments, captive portals or proxy auto-config (PAC) files can also interfere with DNS, but the core issue here is that the smartphone's DNS server address is either statically set to an invalid IP or obtained via DHCP but pointing to a server that no longer responds.

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 220-1201 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.

Visual reference

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 220-1201 question test?

Mobile Device Network Connectivity — This question tests Mobile Device Network Connectivity — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: The smartphone's DNS settings are misconfigured or pointing to a non-functional server. — The smartphone can connect to the Wi-Fi network (Layer 2 connectivity is fine) and other devices work, so the issue is specific to this device's higher-layer configuration. DNS resolution is required to translate domain names to IP addresses; if the smartphone's DNS settings point to a non-functional or incorrect server, it will fail to resolve any hostname, preventing internet access even though the network connection itself is active. This matches the symptom of being connected with full signal but unable to browse.

What should I do if I get this 220-1201 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: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

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

1 more ways this is tested on 220-1201

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's iPhone connects to a public Wi-Fi hotspot but cannot load any web pages. The Wi-Fi icon shows full signal. Other devices on the same network work fine. What is the most likely issue?

medium

A.The iPhone's DNS settings are misconfigured.
✓ B.The iPhone is not accepting the captive portal's terms and conditions.
C.The iPhone's Wi-Fi antenna is faulty.
D.The public Wi-Fi network is using an incompatible security protocol.

Why B: The most likely issue is that the iPhone has connected to the Wi-Fi network but has not completed the captive portal authentication process. Captive portals require users to accept terms and conditions or log in via a web page before internet access is granted. Since other devices work fine, the network itself is functional, and the iPhone's full signal indicates a good physical connection, pointing to a failure in the portal acceptance step.

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Question Discussion

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