- A
ingress: - from: - namespaceSelector: matchLabels: name: frontend
Why wrong: This allows from all pods in the frontend namespace, not just those with label 'role: proxy'.
- B
ingress: - from: - namespaceSelector: matchLabels: name: frontend podSelector: matchLabels: role: proxy
This selects pods with label 'role: proxy' in namespaces that have label 'name: frontend'.
- C
ingress: - from: - ipBlock: cidr: 0.0.0.0/0 - podSelector: matchLabels: role: proxy
Why wrong: This allows from any IP and from pods with label 'role: proxy' in the same namespace, not the desired restriction.
- D
ingress: - from: - podSelector: matchLabels: role: proxy
Why wrong: This selects pods with label 'role: proxy' but only in the same namespace.
CKAD Services and Networking Practice Question
This CKAD 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.
You need to allow ingress traffic to pods in namespace 'api' only from pods in namespace 'frontend' that have label 'role: proxy'. Which NetworkPolicy ingress rule correctly implements this?
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
ingress: - from: - namespaceSelector: matchLabels: name: frontend podSelector: matchLabels: role: proxy
To select pods from another namespace with a specific label, you must use both namespaceSelector and podSelector in the same from item. Option A is correct. Option B allows from any pod in namespace 'frontend' regardless of label. Option C allows from any pod with label 'role: proxy' in any namespace. Option D uses ipBlock which is not needed.
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.
- ✗
ingress: - from: - namespaceSelector: matchLabels: name: frontend
Why it's wrong here
This allows from all pods in the frontend namespace, not just those with label 'role: proxy'.
- ✓
ingress: - from: - namespaceSelector: matchLabels: name: frontend podSelector: matchLabels: role: proxy
Why this is correct
This selects pods with label 'role: proxy' in namespaces that have label 'name: frontend'.
Related concept
CIDR notation defines the prefix length.
- ✗
ingress: - from: - ipBlock: cidr: 0.0.0.0/0 - podSelector: matchLabels: role: proxy
Why it's wrong here
This allows from any IP and from pods with label 'role: proxy' in the same namespace, not the desired restriction.
- ✗
ingress: - from: - podSelector: matchLabels: role: proxy
Why it's wrong here
This selects pods with label 'role: proxy' but only in the same namespace.
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 CKAD subnetting questions on CIDR, address ranges, and subnet selection.
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FAQ
Questions learners often ask
What does this CKAD question test?
Services and Networking — This question tests Services and Networking — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: ingress: - from: - namespaceSelector: matchLabels: name: frontend podSelector: matchLabels: role: proxy — To select pods from another namespace with a specific label, you must use both namespaceSelector and podSelector in the same from item. Option A is correct. Option B allows from any pod in namespace 'frontend' regardless of label. Option C allows from any pod with label 'role: proxy' in any namespace. Option D uses ipBlock which is not needed.
What should I do if I get this CKAD 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 CKAD subnetting questions on CIDR, address ranges, and subnet selection.
What is the key concept behind this question?
CIDR notation defines the prefix length.
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Last reviewed: Jun 21, 2026
This CKAD 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 CKAD exam.
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