This EX200 practice question tests your understanding of manage containers. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A developer reports that a container running a custom web application is failing to start on a Red Hat Enterprise Linux 8 host. The container image is built from a Dockerfile that uses 'EXPOSE 8080'. The host firewall is enabled. Which action is most likely required to allow external access to the application?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Start the container with the '-p 8080:8080' option to publish the port.
The container image's EXPOSE 8080 instruction is metadata that documents the intended port but does not actually publish it. To make the container's port 8080 accessible from the host's network, you must use the '-p 8080:8080' option when starting the container with 'podman run' or 'docker run'. This creates a port mapping from the host's port 8080 to the container's port 8080, allowing external traffic to reach the application.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Start the container with the '-p 8080:8080' option to publish the port.
Why this is correct
Publishing the container port with '-p' makes it accessible through the host.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Open port 8080 in the host firewall using firewall-cmd.
Why it's wrong here
Opening the host firewall port alone does not make the container port accessible; the container port must be published.
✗
Disable the host firewall to allow all incoming traffic.
Why it's wrong here
Disabling the firewall is overly permissive and not a recommended practice.
✗
Ensure the container image includes an EXPOSE instruction for port 8080.
Why it's wrong here
EXPOSE is only documentation; it does not publish the port.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse the EXPOSE instruction (which is just metadata) with actual port publishing, leading them to think the port is automatically accessible or that firewall changes are the primary fix.
Detailed technical explanation
How to think about this question
Container port publishing works through iptables or nftables rules managed by the container runtime (e.g., Podman or Docker). When you use '-p 8080:8080', the runtime creates a DNAT rule that forwards incoming traffic on the host's port 8080 to the container's IP and port 8080. Without this mapping, the container runs in an isolated network namespace and is only reachable from the host itself via its internal IP, not from external clients.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the EX200 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Manage containers — This question tests Manage containers — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Start the container with the '-p 8080:8080' option to publish the port. — The container image's EXPOSE 8080 instruction is metadata that documents the intended port but does not actually publish it. To make the container's port 8080 accessible from the host's network, you must use the '-p 8080:8080' option when starting the container with 'podman run' or 'docker run'. This creates a port mapping from the host's port 8080 to the container's port 8080, allowing external traffic to reach the application.
What should I do if I get this EX200 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This EX200 practice question is part of Courseiva's free Red Hat 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 EX200 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.