100-140 Question 223
Single answerYou are troubleshooting a DNS resolution issue where a user is unable to access www.example.com. You decide to use the 'nslookup' command to verify the DNS records. After running 'nslookup www.example.com', you notice that the command returns a 'Non-existent domain' error. What does this indicate?
- A
The DNS server could not resolve the domain because it does not exist.
- B
The IP address of the DNS server is incorrectly configured on the user’s machine.
- C
The user’s local DNS cache is corrupted.
- D
The network connection between the user and the DNS server is down.
Show answer and explanation
Correct answer: A
Explanation
The 'Non-existent domain' error occurs when the DNS server is successfully contacted but cannot find the requested domain in its records. This indicates that the domain does not exist or is not configured in the DNS server. It is unrelated to local machine issues like DNS cache corruption or DNS server configuration.
- A. Correct.
This is correct. The 'Non-existent domain' error indicates that the DNS server was contacted successfully but could not find the requested domain in its records.
- B. Incorrect.
This is incorrect. If the DNS server’s IP address were incorrectly configured, the 'nslookup' command would fail to connect to the DNS server rather than return a 'Non-existent domain' error.
- C. Incorrect.
This is incorrect. A corrupted local DNS cache could result in incorrect or stale DNS resolutions, but it would not produce a 'Non-existent domain' error in an 'nslookup' query.
- D. Incorrect.
This is incorrect. If the network connection to the DNS server were down, the 'nslookup' command would fail to reach the server entirely, rather than returning a 'Non-existent domain' error.