220-1101 Hardware and Network Troubleshooting Practice Question
A technician is troubleshooting a user's wired desktop that can access local network shares and printers but cannot reach any internet websites. The technician pings the default gateway successfully. Which of the following is the most likely cause of this issue?
⚠ Common exam trap
Candidates often assume internet access failure must be a routing or gateway problem, but the successful ping to the default gateway eliminates that, steering them toward DNS as the overlooked culprit.
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
✓
DNS server configuration is incorrect or the DNS server is unreachable
The user can access local resources (shares, printers) and successfully ping the default gateway, which confirms that Layer 2/3 connectivity, IP addressing, and routing are functional. However, the inability to reach internet websites while local access works points to a name resolution failure. DNS translates domain names to IP addresses; if the DNS server configuration is incorrect or unreachable, the browser cannot resolve website names, even though the network path to the internet is intact.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
DNS server configuration is incorrect or the DNS server is unreachable
Why this is correct
DNS resolution is required to translate a domain name into the destination IP address. Because the workstation can reach local resources directly by IP, the failure is specific to name resolution for internet hosts; an incorrect DNS server address, an unreachable DNS server, or a firewall blocking UDP/TCP port 53 would all produce this exact symptom. Local IP-based traffic does not depend on DNS, so local connectivity remains unaffected.
- ✗
IP address conflict with another device on the network
Why it's wrong here
An IP address conflict causes the DHCP or ARP tables to become unstable, typically leading to intermittent packet loss or complete loss of network connectivity for all destinations. It would not selectively block internet domain name resolution while leaving local IP-based communications intact, because the conflict disrupts Layer 2 and Layer 3 communication at the interface level. Since local resources are accessible reliably, an IP conflict is not a plausible cause.
When this WOULD be correct
A user reports that their computer suddenly loses network connectivity, and other users on the same subnet experience similar issues. The technician finds duplicate IP addresses in the DHCP logs, confirming an IP address conflict.
- ✗
Faulty network interface card (NIC)
Why it's wrong here
A faulty NIC would prevent the network interface from sending or receiving any frames, which means the workstation would lose all network connectivity, including access to local resources by IP address. Since the user can still access local resources and the technician successfully pinged the gateway, the NIC is operating at least at the layer required for IP communication. This option is inconsistent with the observed symptoms.
When this WOULD be correct
If a user cannot access any network resources (local or internet) and the link light is off or blinking abnormally, a faulty NIC would be the likely cause.
- ✗
Incorrect subnet mask on the workstation
Why it's wrong here
An incorrect subnet mask alters the workstation's calculation of which destinations are local versus remote. If the mask is wrong, the workstation may not ARP for the default gateway, breaking all off-subnet communication, including the ping to the gateway that was successful. A correct subnet mask is required for the workstation to properly send traffic to the gateway, so the successful gateway ping rules out this misconfiguration.
When this WOULD be correct
A workstation cannot communicate with any other devices on the network, including the default gateway, and an ipconfig command shows an incorrect subnet mask (e.g., 255.255.0.0 instead of 255.255.255.0).
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 220-1101 exam frequently reuses these exact scenarios with slightly different constraints.
✓DNS server configuration is incorrect or the DNS server is unreachableCorrect answer▾
Why this is correct
DNS resolution is required to translate a domain name into the destination IP address. Because the workstation can reach local resources directly by IP, the failure is specific to name resolution for internet hosts; an incorrect DNS server address, an unreachable DNS server, or a firewall blocking UDP/TCP port 53 would all produce this exact symptom. Local IP-based traffic does not depend on DNS, so local connectivity remains unaffected.
✗IP address conflict with another device on the networkWrong answer — click to see why▾
Why this is wrong here
An IP address conflict typically causes intermittent connectivity or complete loss of network access, but the user can still access local resources and ping the default gateway, indicating the IP configuration is functional for local traffic.
★ When this WOULD be the correct answer
A user reports that their computer suddenly loses network connectivity, and other users on the same subnet experience similar issues. The technician finds duplicate IP addresses in the DHCP logs, confirming an IP address conflict.
Why candidates choose this
Candidates may confuse symptoms of IP conflicts with DNS issues, as both can cause internet access problems, but local connectivity remains intact in DNS issues, not in IP conflicts.
✗Faulty network interface card (NIC)Wrong answer — click to see why▾
Why this is wrong here
A faulty NIC would prevent all network communication, but the user can access local network shares and printers and ping the default gateway, indicating the NIC is functioning correctly.
★ When this WOULD be the correct answer
If a user cannot access any network resources (local or internet) and the link light is off or blinking abnormally, a faulty NIC would be the likely cause.
Why candidates choose this
Candidates may associate any network issue with hardware failure, especially when symptoms are unclear, overlooking that successful local access rules out a faulty NIC.
✗Incorrect subnet mask on the workstationWrong answer — click to see why▾
Why this is wrong here
The user can ping the default gateway successfully, indicating that the subnet mask is correctly configured for local network communication. An incorrect subnet mask would typically prevent reaching the gateway or other local resources.
★ When this WOULD be the correct answer
A workstation cannot communicate with any other devices on the network, including the default gateway, and an ipconfig command shows an incorrect subnet mask (e.g., 255.255.0.0 instead of 255.255.255.0).
Why candidates choose this
Candidates may incorrectly assume that internet access requires a specific subnet mask, or they confuse subnet mask issues with DNS or gateway problems.
Analysis generated from the official 220-1101blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1101 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 220-1101 exam.