LFCS Networking Practice Question
A user reports that they can access websites by IP address but not by domain name. Which command should the administrator use to diagnose the issue?
⚠ Common exam trap
A common mix-up: candidates choose `ping google.com` (Option D) because it's a common connectivity test, but they fail to recognize that the symptom (access by IP but not name) specifically points to DNS, making `dig` the targeted diagnostic tool.
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
✓
dig google.com
The user can access websites by IP address but not by domain name, indicating a DNS resolution failure. The `dig` command is the correct diagnostic tool because it directly queries DNS servers to test domain name resolution, bypassing the system's resolver cache and configuration. This allows the administrator to isolate whether the issue lies with DNS resolution or other network layers.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
dig google.com
Why this is correct
Dig performs DNS lookup and shows resolution details.
- ✗
netstat -r
Why it's wrong here
Netstat -r shows routing table.
- ✗
traceroute 8.8.8.8
Why it's wrong here
Traceroute shows path to IP, not DNS.
- ✗
ping google.com
Why it's wrong here
Ping uses DNS but may fail for other reasons; it's not the best diagnostic.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This LFCS practice question is part of Courseiva's free Linux Foundation 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 LFCS exam.