- A
apiVersion: networking.k8s.io/v1 kind: NetworkPolicy metadata: name: db-egress spec: podSelector: {} policyTypes: - Egress egress: - to: - ipBlock: cidr: 0.0.0.0/0 ports: - port: 5432
Why wrong: This allows egress to any IP on port 5432, not just the database.
- B
apiVersion: networking.k8s.io/v1 kind: NetworkPolicy metadata: name: db-egress spec: podSelector: {} policyTypes: - Egress egress: - to: - podSelector: matchLabels: app: db
Why wrong: This selects a pod selector, not an external IP.
- C
apiVersion: networking.k8s.io/v1 kind: NetworkPolicy metadata: name: db-egress spec: podSelector: {} policyTypes: - Egress egress: []
Why wrong: An empty egress list denies all egress, but does not allow the necessary traffic.
- D
apiVersion: networking.k8s.io/v1 kind: NetworkPolicy metadata: name: db-egress spec: podSelector: {} policyTypes: - Egress egress: - to: - ipBlock: cidr: 10.0.0.5/32 ports: - port: 5432
This policy allows egress only to the specified IP and port, and denies all other egress due to default deny.
CKS Monitoring, Logging and Runtime Security Practice Question
This CKS practice question tests your understanding of monitoring, logging and runtime security. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 need to configure a NetworkPolicy that allows egress traffic only to an external database at IP 10.0.0.5 on port 5432, and denies all other egress. Which policy BEST achieves this?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"best"Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
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
apiVersion: networking.k8s.io/v1 kind: NetworkPolicy metadata: name: db-egress spec: podSelector: {} policyTypes: - Egress egress: - to: - ipBlock: cidr: 10.0.0.5/32 ports: - port: 5432
The correct policy has an egress rule that allows traffic to 10.0.0.5 on port 5432, and no other egress rules, so all other egress is denied by default.
Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
apiVersion: networking.k8s.io/v1 kind: NetworkPolicy metadata: name: db-egress spec: podSelector: {} policyTypes: - Egress egress: - to: - ipBlock: cidr: 0.0.0.0/0 ports: - port: 5432
Why it's wrong here
This allows egress to any IP on port 5432, not just the database.
- ✗
apiVersion: networking.k8s.io/v1 kind: NetworkPolicy metadata: name: db-egress spec: podSelector: {} policyTypes: - Egress egress: - to: - podSelector: matchLabels: app: db
Why it's wrong here
This selects a pod selector, not an external IP.
- ✗
apiVersion: networking.k8s.io/v1 kind: NetworkPolicy metadata: name: db-egress spec: podSelector: {} policyTypes: - Egress egress: []
Why it's wrong here
An empty egress list denies all egress, but does not allow the necessary traffic.
- ✓
apiVersion: networking.k8s.io/v1 kind: NetworkPolicy metadata: name: db-egress spec: podSelector: {} policyTypes: - Egress egress: - to: - ipBlock: cidr: 10.0.0.5/32 ports: - port: 5432
Why this is correct
This policy allows egress only to the specified IP and port, and denies all other egress due to default deny.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
CIDR notation defines the prefix length.
Common exam traps
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Detailed technical explanation
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
- CIDR notation defines the prefix length.
- Block size helps identify subnet boundaries.
- Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
- The required host count determines the smallest suitable subnet.
TExam Day Tips
- Write the block size before choosing the subnet.
- Check whether the question asks for hosts, subnets or a specific address range.
- Do not confuse /24, /25, /26 and /27 host counts.
Key takeaway
Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Real-world example
How this comes up in practice
A network engineer segments a warehouse floor into three subnets: 20 scanners, 5 printers, and 2 management hosts. Picking the wrong mask wastes addresses or leaves too few usable hosts. Exam questions test whether you can apply CIDR notation, calculate block size, and identify the correct usable-host range for a given prefix.
What to study next
Got this wrong? Here's your next step.
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related CKS subnetting questions on CIDR, address ranges, and subnet selection.
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Monitoring, Logging and Runtime Security — study guide chapter
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FAQ
Questions learners often ask
What does this CKS question test?
Monitoring, Logging and Runtime Security — This question tests Monitoring, Logging and Runtime Security — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: apiVersion: networking.k8s.io/v1 kind: NetworkPolicy metadata: name: db-egress spec: podSelector: {} policyTypes: - Egress egress: - to: - ipBlock: cidr: 10.0.0.5/32 ports: - port: 5432 — The correct policy has an egress rule that allows traffic to 10.0.0.5 on port 5432, and no other egress rules, so all other egress is denied by default.
What should I do if I get this CKS question wrong?
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related CKS subnetting questions on CIDR, address ranges, and subnet selection.
Are there clue words in this question I should notice?
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
What is the key concept behind this question?
CIDR notation defines the prefix length.
About these practice questions
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Last reviewed: Jun 21, 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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