XK0-006 Troubleshooting Practice Question
A user reports that a web server is unreachable. The administrator runs 'curl -I https://example.com' and gets no response. Which command should be used next to check if the server is reachable at the network level?
⚠ Common exam trap
Watch out — candidates often choose `ss` or `lsof` because they are familiar with checking local services, but these commands cannot test remote reachability, which is the core of the question.
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
✓
ping -c 4 example.com
The `curl -I` command failed to get a response, which could be due to a network-level issue rather than an application-layer problem. The `ping` command uses ICMP echo requests to test basic IP-level connectivity to the host, bypassing higher-layer protocols like HTTP/TLS. If the server is unreachable at the network layer, `ping` will show packet loss or timeouts, confirming a routing or firewall issue.
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 -c 4 example.com
Why this is correct
ping -c 4 example.com sends four ICMP echo requests, testing IP-level reachability independently of HTTPS. Since curl returned nothing, this isolates whether the host responds at the network layer before investigating TLS, DNS resolution or the web service itself.
- ✗
dig -x example.com
Why it's wrong here
dig is for DNS queries, not connectivity.
- ✗
lsof -i :443
Why it's wrong here
lsof lists open files and sockets on the local machine, showing which local process holds port 443; it never tests whether the remote server responds. It is tempting for checking port conflicts or identifying the process bound to a listener, which is the correct use when a local service fails to start.
- ✗
ss -tlnp | grep 443
Why it's wrong here
ss checks local listening ports, not remote connectivity.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This XK0-006 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 XK0-006 exam.