hardMultiple ChoiceObjective-mapped
XK0-006 Practice Question: A Docker container using port 8080 fails to start…
A Docker container using port 8080 fails to start with the error 'port is already allocated'. Which command should the administrator use to identify the process using that port?
⚠ Common exam trap
Candidates often choose `ss -tln` (option B) because it shows listening ports, but they forget the `-p` flag is required to identify the process, leading to incomplete troubleshooting.
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
✓
ss -tlnp
The `ss -tlnp` command lists TCP listening sockets (`-l`) with numeric addresses (`-n`) and shows the process identifier (PID) and process name (`-p`) that owns each socket. This directly identifies which process has bound port 8080, allowing the administrator to resolve the 'port is already allocated' error.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
ss -tan
Why it's wrong here
Shows all TCP connections, not just listening.
- ✗
ss -tln
Why it's wrong here
Shows listening ports but not the PID.
- ✓
ss -tlnp
Why this is correct
Shows listening TCP ports with PID.
- ✗
ss -r
Why it's wrong here
Shows routing table.
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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.