This CKAD practice question tests your understanding of services and networking. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. 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.
The Ingress controller logs show a 404 error when accessing 'http://example.com/api'. The service 'api-service' exists and is reachable via ClusterIP. What is the most likely cause?
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.
The service 'api-service' is in a different namespace
Why wrong: The Ingress and service must be in the same namespace. If they were in different namespaces, the Ingress would not route to it.
B
The service port (80) does not match the container port
Why wrong: The service port can be different from the container port; the service targets the container port via targetPort.
C
The IngressClass 'nginx' is not installed or configured
The Ingress controller must be configured to process the specified ingressClassName. If the IngressClass is missing, the Ingress will not be processed, resulting in 404.
D
The path '/api' should be pathType: Exact
Why wrong: PathType Prefix should work for '/api' and match '/api' and '/api/'. The issue is not with pathType.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The IngressClass 'nginx' is not installed or configured
The Ingress resource specifies an ingressClassName 'nginx', but if the corresponding IngressClass resource does not exist or the controller is not configured to watch that class, the Ingress will be ignored. Option C is correct. Option A is incorrect because the service port and container port don't need to match; the service targets the container port. Option B is incorrect because the path and pathType are correct. Option D is incorrect because the service must be in the same namespace as the Ingress.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The service 'api-service' is in a different namespace
Why it's wrong here
The Ingress and service must be in the same namespace. If they were in different namespaces, the Ingress would not route to it.
✗
The service port (80) does not match the container port
Why it's wrong here
The service port can be different from the container port; the service targets the container port via targetPort.
✓
The IngressClass 'nginx' is not installed or configured
Why this is correct
The Ingress controller must be configured to process the specified ingressClassName. If the IngressClass is missing, the Ingress will not be processed, resulting in 404.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
✗
The path '/api' should be pathType: Exact
Why it's wrong here
PathType Prefix should work for '/api' and match '/api' and '/api/'. The issue is not with pathType.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CKAD question in full detail.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related CKAD NAT questions on configuration and troubleshooting.
Services and Networking — This question tests Services and Networking — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: The IngressClass 'nginx' is not installed or configured — The Ingress resource specifies an ingressClassName 'nginx', but if the corresponding IngressClass resource does not exist or the controller is not configured to watch that class, the Ingress will be ignored. Option C is correct. Option A is incorrect because the service port and container port don't need to match; the service targets the container port. Option B is incorrect because the path and pathType are correct. Option D is incorrect because the service must be in the same namespace as the Ingress.
What should I do if I get this CKAD question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related CKAD NAT questions on configuration and troubleshooting.
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?
Static NAT maps one inside address to one outside address.
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Question Discussion
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