easyMultiple ChoiceObjective-mapped
DNS Failure: When Ping Works but Websites Don't Load
A user complains that they cannot access any websites, but they can ping external IP addresses like 8.8.8.8 successfully. Other devices on the same network work fine. Which network service is most likely failing on this user's computer?
Quick Answer
The answer is DNS, as the ability to ping external IP addresses like 8.8.8.8 confirms that the network stack, IP configuration, and routing are all functional, while the failure to load websites points directly to a breakdown in name resolution. DNS is the service responsible for translating human-readable domain names into machine-readable IP addresses; when it fails locally, the computer cannot resolve website names even though it can reach those IPs directly. On the CompTIA A+ Core 1 220-1201 exam, this scenario is a classic troubleshooting question designed to test your understanding of the OSI model’s application layer versus the network layer—ping works at Layer 3 (IP), but web browsing requires Layer 7 (DNS). A common trap is to suspect DHCP or NAT, but since other devices on the same network work fine, the issue is isolated to this computer’s DNS configuration. Remember the memory tip: “Ping by IP, fail by name—DNS is the one to blame.”
⚠ Common exam trap
CompTIA A+ often tests the distinction between IP connectivity (ping to IP) and name resolution (ping to hostname), trapping candidates who confuse a working ping to an IP with full internet functionality, when DNS is actually the broken link.
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
The user can ping external IP addresses (e.g., 8.8.8.8) successfully, which confirms that IP connectivity, routing, and NAT are working. However, they cannot access websites by name, which requires DNS resolution to translate domain names into IP addresses. Since other devices on the same network work fine, the issue is isolated to this computer's DNS client configuration or service, making DNS the most likely failing service.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
DHCP
Why it's wrong here
DHCP assigns IP settings; the user has a valid IP and can ping, so DHCP is working.
- ✓
DNS
Why this is correct
DNS resolves domain names to IPs. The user can ping by IP but not by name, so DNS is likely misconfigured or not responding on that machine.
- ✗
NAT
Why it's wrong here
NAT is a router function; if it were failing, all devices would be affected, not just this one.
- ✗
Proxy
Why it's wrong here
A proxy server could cause this, but it's less common in small networks; DNS is the more direct cause given the symptoms.
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Same concept, more angles
2 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 reports that they cannot access any websites, but they can ping the IP address of a public DNS server (8.8.8.8). What is the most likely misconfigured network service?
easy- A.DHCP
- ✓ B.DNS
- C.NAT
- D.Proxy
Why B: The user can ping 8.8.8.8, confirming that IP connectivity and routing are working, but cannot access websites by name. This indicates that the system cannot resolve domain names to IP addresses, which is the function of DNS. A misconfigured DNS server address (e.g., pointing to a non-existent or unreachable DNS server) would cause this exact symptom.
Variation 2. A user reports that they can access internal resources using IP addresses but cannot access them using hostnames. Other users on the same network have no issues. What is the most likely cause?
medium- A.The DHCP server is out of addresses
- B.The DNS server is down
- ✓ C.The user's DNS settings are incorrect
- D.The router's NAT is misconfigured
Why C: The ability to use IP addresses but not hostnames points to a DNS resolution problem on the user's device. This could be due to a misconfigured DNS server address in the network settings or a local hosts file issue. Other users working normally suggests the problem is client-specific.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1201 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 220-1201 exam.