CV0-004 Troubleshooting Practice Question
Exhibit
Refer to the exhibit. ``` $ sudo systemctl status nginx ● nginx.service - A high performance web server and a reverse proxy server Loaded: loaded (/usr/lib/systemd/system/nginx.service; enabled; vendor preset: disabled) Active: failed (Result: exit-code) since Mon 2024-03-25 10:23:45 UTC; 1min 30s ago Process: 12345 ExecStart=/usr/sbin/nginx (code=exited, status=1/FAILURE) Main PID: 12345 (code=exited, status=1/FAILURE) CGroup: /system.slice/nginx.service Mar 25 10:23:45 web01 systemd[1]: Starting nginx... Mar 25 10:23:45 web01 nginx[12345]: nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use) Mar 25 10:23:45 web01 nginx[12345]: nginx: [emerg] still could not bind() ```
A cloud administrator is starting the nginx web server on a new cloud VM but it fails. According to the exhibit, what is the most likely cause of the failure?
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
✓
Another service is already listening on port 80
The error 'bind() to 0.0.0.0:80 failed (98: Address already in use)' indicates that port 80 is already occupied by another process. Option A is correct. Option B is wrong because SELinux would give a permission denied error, not address in use. Option C is wrong because the error says address in use, not file not found. Option D is wrong because the error is about binding, not about configuration syntax.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Another service is already listening on port 80
Why this is correct
The error explicitly states address already in use.
- ✗
The VM does not have network connectivity
Why it's wrong here
The error shows the bind attempt; connectivity is not the issue.
- ✗
SELinux is blocking nginx from binding to the port
Why it's wrong here
SELinux would produce an AVC denial, not 'address in use'.
- ✗
The nginx configuration file has a syntax error
Why it's wrong here
Syntax errors would be reported differently, not as bind failure.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CV0-004 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 CV0-004 exam.