This CKA practice question tests your understanding of services and networking. 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.
Which THREE of the following are true about NetworkPolicy? (Select THREE.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
NetworkPolicy requires a CNI plugin that supports it
NetworkPolicy relies on the CNI plugin to enforce its rules. The Kubernetes API only stores the policy definition; the actual packet filtering is performed by the underlying network plugin (e.g., Calico, Cilium, Weave Net). Without a CNI plugin that supports NetworkPolicy, the policy objects are created but have no effect on traffic.
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 is a cluster-scoped resource
Why it's wrong here
NetworkPolicy is namespaced.
✗
NetworkPolicy can only allow traffic, not deny
Why it's wrong here
NetworkPolicy denies by default; rules only allow traffic.
✓
NetworkPolicy requires a CNI plugin that supports it
Why this is correct
Not all CNI plugins implement NetworkPolicy.
Related concept
Read the scenario before looking for a memorised answer.
✓
If no NetworkPolicy selects a pod, traffic to that pod is allowed
Why this is correct
Without a policy, all traffic is allowed by default.
Related concept
Read the scenario before looking for a memorised answer.
✓
NetworkPolicy can be applied to a subset of pods using podSelector
Why this is correct
spec.podSelector selects pods to which the policy applies.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume NetworkPolicy can explicitly deny traffic (like a firewall rule), but Kubernetes NetworkPolicy only supports allow rules; denial is implicit when a policy selects a pod and does not include a rule for that traffic.
Detailed technical explanation
How to think about this question
NetworkPolicy rules are evaluated using iptables or eBPF under the hood, depending on the CNI plugin. A subtle behavior is that NetworkPolicy uses a whitelist model: when at least one policy selects a pod, all traffic is denied unless explicitly allowed by a rule. This means that adding a policy that only allows ingress from a specific source will also deny all other ingress traffic, including traffic from other pods in the same namespace that are not matched.
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CKA question in full detail.
Services and Networking — This question tests Services and Networking — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: NetworkPolicy requires a CNI plugin that supports it — NetworkPolicy relies on the CNI plugin to enforce its rules. The Kubernetes API only stores the policy definition; the actual packet filtering is performed by the underlying network plugin (e.g., Calico, Cilium, Weave Net). Without a CNI plugin that supports NetworkPolicy, the policy objects are created but have no effect on traffic.
What should I do if I get this CKA 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.
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Question Discussion
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