220-1101 Networking Practice Question
A user reports that they cannot access the internet, but they can access internal network resources by IP address. The technician runs ipconfig and sees IP address 192.168.1.12, subnet mask 255.255.255.0, default gateway 192.168.1.1, DNS server 192.168.1.1. The user can ping 192.168.1.1 and 8.8.8.8 successfully. However, they cannot ping www.google.com. Which of the following is the MOST likely cause?
⚠ Common exam trap
Test-takers frequently assume a successful ping to an external IP (8.8.8.8) means the internet is fully working, overlooking that DNS resolution is a separate service that can fail even when IP connectivity is intact.
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 DNS server is not resolving hostnames.
The user can ping the default gateway (192.168.1.1) and an external IP (8.8.8.8) successfully, which confirms that the network layer (IP routing) is working and the internet connection is functional. However, the inability to ping www.google.com by name while being able to ping by IP indicates that the DNS server (192.168.1.1) is failing to resolve the hostname to an IP address. Since the DNS server is the same as the default gateway, it is likely that the gateway device is not configured to perform DNS resolution or the DNS service is not running.
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 default gateway is unreachable.
Why it's wrong here
If the default gateway were unreachable, the user would be unable to reach any destination outside the local subnet, including public IP addresses. Since the user successfully pinged 192.168.1.1 and can reach external IPs, the gateway is functioning correctly. This rules out a routing or gateway failure as the cause. The actual failure is limited to name resolution, not packet forwarding.
When this WOULD be correct
A user cannot access the internet or internal resources, and ipconfig shows an incorrect default gateway or ping to the gateway fails. This indicates the gateway is unreachable.
- ✓
The DNS server is not resolving hostnames.
Why this is correct
Since the user can reach external IPs but not hostnames, the DNS server is failing to translate domain names to IP addresses. This could be due to a DNS server failure or incorrect DNS configuration.
- ✗
The subnet mask is incorrect.
Why it's wrong here
An incorrect subnet mask typically causes reachability problems for hosts on other subnets because the host misclassifies those destinations as local and attempts ARP instead of sending to the gateway. Since the user can reach both internal resources and external IPs through the gateway, the mask is consistent with the network topology. A misconfigured mask might still allow gateway pings, but it would not selectively block DNS hostname resolution while allowing data traffic.
When this WOULD be correct
A user cannot access any network resources, including internal ones, and ipconfig shows an incorrect subnet mask (e.g., 255.255.0.0 for a /24 network) causing the device to believe it is on a different subnet, leading to communication failures.
- ✗
The NIC is faulty.
Why it's wrong here
A faulty NIC would prevent all network communication—the host would lose link, fail to acquire an address, or drop all packets at layer 2. The user can ping the gateway and internal resources, so the NIC is transmitting and receiving frames normally. This symptom pattern (working IP connectivity but broken hostname resolution) cannot be explained by hardware failure. Therefore the NIC is healthy and not the root cause.
When this WOULD be correct
A user cannot access any network resources (internal or external) and ipconfig shows an APIPA address (169.254.x.x) or no link light. In that scenario, a faulty NIC would be a likely cause.
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.
✓The DNS server is not resolving hostnames.Correct answer▾
Why this is correct
Since the user can reach external IPs but not hostnames, the DNS server is failing to translate domain names to IP addresses. This could be due to a DNS server failure or incorrect DNS configuration.
✗The default gateway is unreachable.Wrong answer — click to see why▾
Why this is wrong here
The user can successfully ping the default gateway (192.168.1.1), so the gateway is reachable. The issue is DNS resolution, not gateway connectivity.
★ When this WOULD be the correct answer
A user cannot access the internet or internal resources, and ipconfig shows an incorrect default gateway or ping to the gateway fails. This indicates the gateway is unreachable.
Why candidates choose this
Candidates often assume internet access failure is due to gateway issues, but here the gateway is reachable; they overlook that DNS is separate from gateway connectivity.
✗The subnet mask is incorrect.Wrong answer — click to see why▾
Why this is wrong here
The subnet mask 255.255.255.0 is correct for a /24 network, and the user can ping internal resources and the default gateway, so the subnet mask is not the issue.
★ When this WOULD be the correct answer
A user cannot access any network resources, including internal ones, and ipconfig shows an incorrect subnet mask (e.g., 255.255.0.0 for a /24 network) causing the device to believe it is on a different subnet, leading to communication failures.
Why candidates choose this
Candidates may think an incorrect subnet mask could cause internet access issues, but here internal access works, ruling it out.
✗The NIC is faulty.Wrong answer — click to see why▾
Why this is wrong here
The user can ping 8.8.8.8 successfully, which demonstrates that the NIC is functioning correctly and can send/receive packets over the network.
★ When this WOULD be the correct answer
A user cannot access any network resources (internal or external) and ipconfig shows an APIPA address (169.254.x.x) or no link light. In that scenario, a faulty NIC would be a likely cause.
Why candidates choose this
Candidates may assume that any connectivity issue is due to hardware failure, especially when they cannot resolve hostnames, without verifying that basic IP communication (like pinging an external IP) works.
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?”
Visual reference
Quick reference
OSI Model Reference
| Layer | Name | PDU | Key Protocols / Devices |
|---|---|---|---|
| 7 | Application | Data | HTTP, HTTPS, DNS, SMTP, FTP, SSH |
| 6 | Presentation | Data | TLS / SSL, JPEG, ASCII encoding |
| 5 | Session | Data | NetBIOS, RPC, SIP |
| 4 | Transport | Segment / Datagram | TCP, UDP |
| 3 | Network | Packet | IP, ICMP, OSPF — Routers |
| 2 | Data Link | Frame | Ethernet, Wi-Fi, PPP — Switches, Bridges |
| 1 | Physical | Bits | Cables, NICs, Hubs, Repeaters |
Go deeper
Related to this question
Learn chapter
Network Command Tools: ping, ipconfig, nslookup, tracert
Key term
Internet Protocol
Internet Protocol (IP) is the set of rules that governs how data is addressed, routed, and sent from one device to another across networks, including the internet.
Key term
Fully Qualified Domain Name
A Fully Qualified Domain Name is the complete and unambiguous website or server name that includes the host, domain, and top-level domain, leaving no room for guesswork.
About these practice questions
Courseiva writes every 220-1101 question from scratch — 896 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
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.