Question 130 of 991

Services and Networking →hardMultiple SelectObjective-mapped

CKAD Services and Networking Practice Question

This CKAD practice question tests your understanding of services and networking. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 statements about NetworkPolicy are correct? (Select 3)

Question 1hardmulti select

Full question →

A
NetworkPolicy follows an allow-list model; if no policy matches, traffic is denied.
The default behavior is deny if any policy selects the pod; otherwise, traffic is allowed. But with policies, it's allow-list.
B
NetworkPolicy can block traffic to specific external IP addresses using ipBlock.
Why wrong: ipBlock can be used in egress rules to restrict traffic to external IPs, but it can block or allow; the statement is ambiguous. Typically, ipBlock is used to allow traffic to external IPs. But actually, you can block by not including the IP in an allow rule. However, the statement is 'block traffic to specific external IP addresses' which is possible by not including them in an allow egress rule. But the default is deny, so you need to allow specific IPs. The statement is misleading. In practice, NetworkPolicy controls traffic to/from pods; it doesn't directly block external IPs unless you have a deny-all egress and then allow only specific CIDRs. But the statement is too absolute. I consider it false because NetworkPolicy is not a firewall for arbitrary external IPs.
C
NetworkPolicy can use namespaceSelector to allow traffic from all pods in a namespace.
NamespaceSelector selects namespaces by labels.
D
NetworkPolicy is a cluster-scoped resource.
Why wrong: NetworkPolicy is namespaced.
E
NetworkPolicy can restrict egress traffic from pods.
Egress rules control outbound traffic.

Full breakdown with real-world context →

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 follows an allow-list model; if no policy matches, traffic is denied.

Options A, C, and E are correct. NetworkPolicy can allow traffic from specific namespaces, it can restrict egress, and it is an allow-list model (default deny, then allow). Option B is false because NetworkPolicy is namespace-scoped. Option D is false because NetworkPolicy cannot block traffic to external IPs directly; it can only control traffic to/from pods.

Key principle: ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.

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 follows an allow-list model; if no policy matches, traffic is denied.
Why this is correct
The default behavior is deny if any policy selects the pod; otherwise, traffic is allowed. But with policies, it's allow-list.
Related concept
Standard ACLs match source addresses.
✗
NetworkPolicy can block traffic to specific external IP addresses using ipBlock.
Why it's wrong here
ipBlock can be used in egress rules to restrict traffic to external IPs, but it can block or allow; the statement is ambiguous. Typically, ipBlock is used to allow traffic to external IPs. But actually, you can block by not including the IP in an allow rule. However, the statement is 'block traffic to specific external IP addresses' which is possible by not including them in an allow egress rule. But the default is deny, so you need to allow specific IPs. The statement is misleading. In practice, NetworkPolicy controls traffic to/from pods; it doesn't directly block external IPs unless you have a deny-all egress and then allow only specific CIDRs. But the statement is too absolute. I consider it false because NetworkPolicy is not a firewall for arbitrary external IPs.
✓
NetworkPolicy can use namespaceSelector to allow traffic from all pods in a namespace.
Why this is correct
NamespaceSelector selects namespaces by labels.
Related concept
Standard ACLs match source addresses.
✗
NetworkPolicy is a cluster-scoped resource.
Why it's wrong here
NetworkPolicy is namespaced.
✓
NetworkPolicy can restrict egress traffic from pods.
Why this is correct
Egress rules control outbound traffic.
Related concept
Standard ACLs match source addresses.

Common exam traps

Common exam trap: ACLs stop at the first match

ACLs are processed top to bottom. The first matching entry wins, and an implicit deny usually exists at the end.

Trap categories for this question

Real-world vs exam trap
ipBlock can be used in egress rules to restrict traffic to external IPs, but it can block or allow; the statement is ambiguous. Typically, ipBlock is used to allow traffic to external IPs. But actually, you can block by not including the IP in an allow rule. However, the statement is 'block traffic to specific external IP addresses' which is possible by not including them in an allow egress rule. But the default is deny, so you need to allow specific IPs. The statement is misleading. In practice, NetworkPolicy controls traffic to/from pods; it doesn't directly block external IPs unless you have a deny-all egress and then allow only specific CIDRs. But the statement is too absolute. I consider it false because NetworkPolicy is not a firewall for arbitrary external IPs.

Detailed technical explanation

How to think about this question

ACL questions test precision: source, destination, protocol, port and direction. A generally correct ACL can still fail if it is applied on the wrong interface or in the wrong direction.

KKey Concepts to Remember

Standard ACLs match source addresses.
Extended ACLs can match source, destination, protocol and ports.
The first matching ACL entry is used.
There is usually an implicit deny at the end.

TExam Day Tips

Check inbound versus outbound direction.
Read the ACL from top to bottom.
Look for a broader permit or deny above the intended line.

Key takeaway

ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.

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.

Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related CKAD ACL questions on filtering logic and placement.

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FAQ

Questions learners often ask

What does this CKAD question test?

Services and Networking — This question tests Services and Networking — Standard ACLs match source addresses..

What is the correct answer to this question?

The correct answer is: NetworkPolicy follows an allow-list model; if no policy matches, traffic is denied. — Options A, C, and E are correct. NetworkPolicy can allow traffic from specific namespaces, it can restrict egress, and it is an allow-list model (default deny, then allow). Option B is false because NetworkPolicy is namespace-scoped. Option D is false because NetworkPolicy cannot block traffic to external IPs directly; it can only control traffic to/from pods.

What should I do if I get this CKAD question wrong?

What is the key concept behind this question?

Standard ACLs match source addresses.

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Last reviewed: Jun 21, 2026

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