- A
NetworkPolicy with podSelector: matchLabels: app: kubernetes-dashboard, policyTypes: [Ingress], ingress: [{from: [{namespaceSelector: {matchLabels: {}}}]}]
Why wrong: This allows ingress from all namespaces, which is too permissive.
- B
NetworkPolicy with podSelector: matchLabels: app: kubernetes-dashboard, policyTypes: [Ingress], ingress: []
An empty ingress list with Ingress policy type denies all ingress traffic.
- C
NetworkPolicy with podSelector: matchLabels: app: kubernetes-dashboard, policyTypes: [Ingress], ingress: [{from: [{podSelector: {matchLabels: {app: kubernetes-dashboard}}}]}]
Why wrong: This allows ingress from the dashboard pods themselves, not from external.
- D
NetworkPolicy with podSelector: matchLabels: app: kubernetes-dashboard, policyTypes: [Egress], egress: [{to: [{podSelector: {}}]}]
Why wrong: Egress policy does not restrict ingress.
CKS Cluster Setup and Hardening Practice Question
This CKS practice question tests your understanding of cluster setup and hardening. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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.
You are asked to ensure that a specific Kubernetes dashboard (e.g., kubernetes-dashboard) is not publicly accessible. The dashboard is deployed in the 'kube-system' namespace. Which NetworkPolicy should you apply?
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
NetworkPolicy with podSelector: matchLabels: app: kubernetes-dashboard, policyTypes: [Ingress], ingress: []
Option B is correct because a NetworkPolicy with an empty `ingress` array (i.e., `ingress: []`) explicitly denies all inbound traffic to the selected pods. This ensures that the kubernetes-dashboard pod in the kube-system namespace is not publicly accessible, as no ingress rules are defined to allow any source. By default, if no NetworkPolicy selects a pod, all traffic is allowed; applying this policy changes the default to deny for ingress.
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.
- ✗
NetworkPolicy with podSelector: matchLabels: app: kubernetes-dashboard, policyTypes: [Ingress], ingress: [{from: [{namespaceSelector: {matchLabels: {}}}]}]
Why it's wrong here
This allows ingress from all namespaces, which is too permissive.
- ✓
NetworkPolicy with podSelector: matchLabels: app: kubernetes-dashboard, policyTypes: [Ingress], ingress: []
Why this is correct
An empty ingress list with Ingress policy type denies all ingress traffic.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
NetworkPolicy with podSelector: matchLabels: app: kubernetes-dashboard, policyTypes: [Ingress], ingress: [{from: [{podSelector: {matchLabels: {app: kubernetes-dashboard}}}]}]
Why it's wrong here
This allows ingress from the dashboard pods themselves, not from external.
- ✗
NetworkPolicy with podSelector: matchLabels: app: kubernetes-dashboard, policyTypes: [Egress], egress: [{to: [{podSelector: {}}]}]
Why it's wrong here
Egress policy does not restrict ingress.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often think an empty `ingress: []` means 'no restriction' (like an empty allow list) or confuse it with omitting the `ingress` field entirely, but in NetworkPolicy, an empty array explicitly denies all ingress traffic, while omitting the field leaves the default allow behavior unchanged.
Detailed technical explanation
How to think about this question
NetworkPolicy operates on a default-deny model for the traffic direction it specifies: when a policy selects a pod and defines `policyTypes: [Ingress]` with an empty `ingress` list, all inbound traffic is dropped by the network plugin (e.g., Calico, Cilium). This is because the policy explicitly sets the ingress rules to none, overriding the default allow-all behavior. In practice, this is the standard way to isolate a pod completely from incoming connections, even from within the same cluster, unless a more permissive policy is applied later.
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 security administrator must allow nursing staff to reach a patient records server while blocking access from the guest Wi-Fi VLAN. After applying an extended ACL, traffic is still blocked from nursing workstations. The ACL was applied outbound instead of inbound on the wrong interface. Questions like this test ACL direction and placement rules.
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.
- →
Cluster Setup and Hardening — study guide chapter
Learn the concepts, then practise the questions
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FAQ
Questions learners often ask
What does this CKS question test?
Cluster Setup and Hardening — This question tests Cluster Setup and Hardening — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: NetworkPolicy with podSelector: matchLabels: app: kubernetes-dashboard, policyTypes: [Ingress], ingress: [] — Option B is correct because a NetworkPolicy with an empty `ingress` array (i.e., `ingress: []`) explicitly denies all inbound traffic to the selected pods. This ensures that the kubernetes-dashboard pod in the kube-system namespace is not publicly accessible, as no ingress rules are defined to allow any source. By default, if no NetworkPolicy selects a pod, all traffic is allowed; applying this policy changes the default to deny for ingress.
What should I do if I get this CKS question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jun 24, 2026
This CKS practice question is part of Courseiva's free CNCF 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 CKS exam.
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