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220-1201 Practice Question: A technician is troubleshooting a user's computer…
A technician is troubleshooting a user's computer that can reach internal servers by IP address but not by hostname. Other computers on the same subnet work correctly. Which tool should the technician use to check the computer's DNS resolution?
⚠ Common exam trap
Watch out — candidates often choose `ipconfig /flushdns` (Option B) thinking it will fix the problem, but the question asks for a tool to *check* DNS resolution, not to clear the cache; `nslookup` is the correct diagnostic command.
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
✓
nslookup
The user's computer can reach internal servers by IP address but not by hostname, and other computers on the same subnet work correctly. This isolates the problem to the local DNS resolution on the affected machine. The `nslookup` tool is specifically designed to query DNS servers and verify whether a hostname resolves to the correct IP address, making it the appropriate tool to diagnose the DNS resolution failure.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Ping
Why it's wrong here
Ping sends ICMP Echo Request packets to a target IP address to verify basic network layer connectivity and measure round-trip time. While it can be used with a hostname (e.g., ping google.com), the system first performs a DNS lookup *before* sending the ICMP packets. If the DNS lookup fails, Ping will report that the host could not be found, but it doesn't provide details about *why* DNS failed or which DNS server was queried. Therefore, it's not a diagnostic tool for DNS itself, only for reachability once a name is resolved.
- ✗
ipconfig /flushdns
Why it's wrong here
The ipconfig /flushdns command clears the local DNS resolver cache on the client machine. This action is useful for troubleshooting stale or corrupted DNS entries that might be preventing a system from resolving a hostname correctly, forcing it to query a DNS server again. However, flushing the cache is a remedial action, not a diagnostic one; it does not actively test the functionality or responsiveness of the configured DNS servers themselves, nor does it report on their ability to resolve names.
- ✓
nslookup
Why this is correct
nslookup (Name Server Lookup) is a command-line utility specifically designed to query Domain Name System (DNS) servers to obtain domain name or IP address mapping information. It allows a technician to specify a hostname and see which DNS server is being used for resolution, the IP address returned, and even query different DNS record types or specific DNS servers. This direct interaction with DNS servers makes it an ideal tool for diagnosing whether DNS resolution is functioning correctly and identifying potential issues with DNS server configuration or responsiveness.
- ✗
Netstat
Why it's wrong here
Netstat (Network Statistics) is a command-line utility that displays active network connections, routing tables, and a number of network interface statistics. It provides information about which ports are open and listening, which connections are established, and the protocols in use. While crucial for network troubleshooting related to open ports or active sessions, Netstat does not provide any direct insight into the process of DNS name resolution, nor does it query DNS servers or display DNS cache information.
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Related to this question
Learn chapter
IPv4 Address Classes and Ranges
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.
Key term
DNS
DNS is the system that translates human-friendly domain names like example.com into machine-readable IP addresses so computers can find each other on a network.
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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.