200-901 Application Deployment and Security Practice Question
A developer is creating a Dockerfile for a Python Flask application. The application runs on port 5000. Which directive should be used to document that the container listens on this port?
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
✓
EXPOSE 5000
The EXPOSE directive informs Docker that the container listens on specified ports at runtime. It does not actually publish the port but serves as documentation.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
EXPOSE 5000
Why this is correct
Correct. EXPOSE documents the port the container listens on.
- ✗
PORT 5000
Why it's wrong here
Incorrect. There is no PORT directive in Dockerfile.
- ✗
PUBLISH 5000
Why it's wrong here
Incorrect. The publish operation is done at runtime with -p, not in Dockerfile.
- ✗
LISTEN 5000
Why it's wrong here
Incorrect. LISTEN is not a Dockerfile directive.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-901 practice question is part of Courseiva's free Cisco 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 200-901 exam.