This CKS practice question tests your understanding of cluster setup and hardening. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 are valid ways to restrict access to the Kubernetes API server?
Why wrong: Webhook token authentication is an authentication method, but does not restrict access by itself; it can be part of a solution, but not a direct restriction. The best answers are A, B, C.
D
Use TLS client certificate authentication
Client certs authenticate users.
E
Set the API server's bind address to 0.0.0.0
Why wrong: This listens on all interfaces, increasing exposure.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Disable anonymous authentication
A is correct because disabling anonymous authentication (via the `--anonymous-auth=false` flag on the API server) removes the ability for unauthenticated requests to reach the API server. This forces all requests to present valid credentials, thereby restricting access to only authenticated users.
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.
✓
Disable anonymous authentication
Why this is correct
Prevents unauthenticated access.
Related concept
Read the scenario before looking for a memorised answer.
✓
Enable RBAC authorization mode
Why this is correct
RBAC restricts what authenticated users can do.
Related concept
Read the scenario before looking for a memorised answer.
✗
Use webhook token authentication
Why it's wrong here
Webhook token authentication is an authentication method, but does not restrict access by itself; it can be part of a solution, but not a direct restriction. The best answers are A, B, C.
✓
Use TLS client certificate authentication
Why this is correct
Client certs authenticate users.
Related concept
Read the scenario before looking for a memorised answer.
✗
Set the API server's bind address to 0.0.0.0
Why it's wrong here
This listens on all interfaces, increasing exposure.
Common exam traps
Common exam trap: answer the scenario, not the keyword
CNCF often tests the distinction between authentication (who you are) and authorization (what you can do), so candidates may mistakenly think webhook token authentication restricts access when it only identifies the user, and may overlook that binding to 0.0.0.0 is a security risk, not a restriction.
Detailed technical explanation
How to think about this question
Under the hood, the API server's `--anonymous-auth` flag defaults to `true`, allowing anonymous requests to be treated as user `system:anonymous`. Disabling it forces every request to carry a valid credential (e.g., a bearer token or client certificate). In a real-world scenario, a cluster with anonymous auth enabled and RBAC misconfigured could allow unauthenticated users to read secrets or escalate privileges, which is why the CIS Benchmark recommends disabling it in production.
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 junior network technician can log in to a core router but cannot reach the enable prompt or configuration mode. The AAA server is authenticating the login — but the authorisation policy only grants privilege level 1, not 15. Authentication (who you are) is working; authorisation (what you can do) is not.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CKS question in full detail.
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: Disable anonymous authentication — A is correct because disabling anonymous authentication (via the `--anonymous-auth=false` flag on the API server) removes the ability for unauthenticated requests to reach the API server. This forces all requests to present valid credentials, thereby restricting access to only authenticated users.
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.
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Question Discussion
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