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EX280 · domain

Networking And Network Policies

This domain covers OpenShift Container Platform 4.14 networking: ClusterIP and NodePort Services, Routes (edge, re-encrypt, passthrough), Ingress, DNS via the cluster DNS Operator, and NetworkPolicy objects enforced by OVN-Kubernetes. You are tested by diagnosing broken name resolution or connectivity and by writing YAML that permits only the intended pod-to-pod traffic.

57 questions23 easy21 medium13 hard

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What this domain covers

What to know about Networking And Network Policies

You must be able to expose an application with a Service and Route, and to write a NetworkPolicy that allows only specified pods on a given port while denying the rest. The critical detail is matching the correct podSelector and namespaceSelector labels so the policy actually selects the intended pods.

Creating and editing Services, Routes, and Ingress with oc expose and oc create route

Configuring NetworkPolicy ingress and egress rules with podSelector, namespaceSelector, and ipBlock

Diagnosing cluster DNS resolution using oc exec, dig, and the dns-default pods

Choosing edge, re-encrypt, or passthrough Route termination and supplying the required certificates

Watch out for

Common Networking And Network Policies exam traps

  • ▸Writing a NetworkPolicy that selects the wrong namespace: namespaceSelector matches namespace labels, not namespace names, unless you use kubernetes.io/metadata.name.
  • ▸Assuming a NetworkPolicy denies traffic by default: with no policy selecting a pod, all ingress and egress is allowed.
  • ▸Forgetting that passthrough Routes cannot use the default router certificate and require the backend to terminate TLS itself.

Question index

All Networking And Network Policies questions (57)

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1

A service of type NodePort has been created in OpenShift. Within what default port range are NodePort services typically allocated on the worker nodes?

Easy
2

An administrator needs to restrict ingress traffic to pods in the 'frontend' namespace so that only pods labeled role=api in the 'backend' namespace can connect on TCP port 8080. All other traffic must be denied. Which NetworkPolicy configuration achieves this?

Medium
3

An OpenShift administrator needs to restrict external access to a specific application Route by limiting access to a predefined list of allowed client IP addresses. How can this be accomplished?

Hard
4

An administrator must configure a NetworkPolicy in the 'secure-zone' namespace to explicitly deny all ingress traffic except for TCP traffic coming from pods labeled 'tier=frontend' in the 'frontend-zone' namespace. Which NetworkPolicy specification achieves this?

Hard
5

An administrator troubleshoots a failing NetworkPolicy and wants to verify if the OpenShift SDN or OVN-Kubernetes controller has successfully applied the rules. Where are the controller operator logs examined?

Hard
6

A developer wants to expose an application using a secure Route that terminates TLS on the pod itself, avoiding decryption at the router layer. Which TLS termination type should be selected?

Easy
7

An administrator needs to expose an internal application running on port 8080 via an OpenShift Route using edge termination. Which object configuration correctly defines this Route?

Easy
8

An administrator needs to create a service that exposes an application externally via an IP address allocated from an external cloud provider load balancer. Which service type must be used?

Easy
9

An administrator needs to modify the default Ingress controller configuration to change its replica count and adjust the router deployment parameters. Which resource should the administrator edit?

Hard
10

Which TWO components are core parts of the OpenShift DNS architecture for cluster resolution? (Choose TWO)

Easy
11

An application pod in OpenShift needs to determine its own IP address and the cluster DNS servers dynamically. Where does CoreDNS look or how are pods configured to resolve cluster DNS?

Medium
12

An administrator needs to test DNS resolution from inside a running pod. Which command run inside a container uses the standard Linux DNS lookup utility?

Easy
13

Which TWO options describe characteristics of OVN-Kubernetes compared to the legacy OpenShift SDN? (Choose TWO)

Medium
14

An application pod needs to discover other pods behind the same headless service. What characteristic defines a headless service?

Easy
15

An administrator wants to expose a Deployment via a NodePort service. What is the default port range allocated for NodePort services in OpenShift if not explicitly configured otherwise?

Easy
16

A developer deploys a headless service (ClusterIP set to None) in OpenShift. What is the primary characteristic of a headless service?

Medium
17

Which TWO of the following are valid OpenShift Service types? (Choose TWO)

Easy
18

An administrator needs to list all Services across all namespaces in the OpenShift cluster. Which command should be used?

Easy
19

Which TWO statements are true regarding OpenShift Services of type LoadBalancer? (Choose TWO)

Hard
20

An administrator is troubleshooting why a Pod in namespace `app-a` cannot reach a Pod in namespace `app-b` on TCP port 3306, even though both Pods are Running and the Services resolve correctly. A NetworkPolicy in `app-b` allows ingress only from Pods labeled `tier: frontend` in `app-a`. The source Pod in `app-a` has the label `tier: backend`. What is the most likely cause?

Medium
21

An OpenShift administrator needs to inspect how OVN-Kubernetes handles network flows and packet drops on a specific node. Which debugging utility installed in the OVN node container is most effective for viewing OpenFlow rules?

Hard
22

An administrator needs to delete a Service named 'old-service' in the 'test' namespace. Which command accomplishes this?

Easy
23

Which TWO options are valid methods to check service endpoints in OpenShift? (Choose TWO)

Easy
24

An administrator configures an EgressFirewall in a namespace to deny all external traffic except for a specific CIDR block. In what order are the rules in an EgressFirewall evaluated?

Hard
25

Which TWO commands are used to check the health and status of the cluster networking operator? (Choose TWO)

Easy
26

An administrator needs to expose an existing deployment using a quick command without writing a YAML manifest. Which command exposes port 8080 of a deployment named 'my-app' as a Service?

Easy
27

When configuring a NetworkPolicy in OpenShift, which THREE options represent valid components or fields within a NetworkPolicy specification? (Choose THREE)

Medium
28

An administrator wants to view the public URL assigned to an existing Route named 'webapp'. Which oc command is best suited to extract only the host URL value?

Easy
29

An administrator wants to test network connectivity from a pod named 'app-pod-1' to a service port on 'backend-service' using TCP. Which tool is commonly available and ideal for testing TCP port connectivity inside a container?

Easy
30

An administrator observes that pods in a specific namespace are unable to resolve external domain names (e.g., www.redhat.com) while internal service resolution works perfectly. What is the most likely cause of this issue in CoreDNS configuration?

Hard
31

An administrator wants to configure a NetworkPolicy that allows incoming traffic only from pods with the label 'role=frontend' residing in any namespace, provided those namespaces have the label 'environment=production'. How should the namespaceSelector and podSelector be combined?

Hard
32

An administrator notices that pods on different worker nodes cannot communicate with each other. Upon checking the cluster network operator, it appears the MTU settings between the underlying physical network and the cluster overlay network mismatch. Which OpenShift command checks the cluster network operator status?

Medium
33

Which THREE actions can be performed using the IngressController custom resource? (Choose THREE)

Medium
34

Which THREE of the following components are part of the standard OpenShift Ingress architecture? (Choose THREE)

Medium
35

Which TWO tools or protocols can an administrator use to verify internal cluster DNS resolution from a pod? (Choose TWO)

Easy
36

An administrator created a Route but external clients receive a 503 Service Unavailable error when attempting to access it. Upon checking the endpoints of the Service referenced by the Route, the administrator discovers there are zero endpoints listed. What is the most likely cause?

Medium
37

An administrator wants to check the status of all cluster operators, specifically verifying that the Network and DNS operators are healthy. Which command should be run?

Easy
38

An administrator needs to configure a Route that handles encrypted communication both from the client to the router AND from the router to the backend pod. Which termination type is required?

Medium
39

Which THREE actions can be performed when managing Route objects in OpenShift? (Choose THREE)

Hard
40

Which TWO methods can an administrator use to troubleshoot why a pod cannot connect to a remote Service? (Choose TWO)

Medium
41

An administrator notices that client source IP addresses are lost when traffic hits a Service of type NodePort, appearing instead as a node IP. Which field in the Service specification should be changed to 'Local' to preserve client source IPs?

Medium
42

An administrator needs to create a passthrough Route that preserves client certificates and forwards encrypted traffic directly to the backend pod. Which spec configuration is required?

Easy
43

An administrator needs to check the internal DNS resolution of a service named 'backend' within the 'production' namespace from a debug pod. Which DNS name is fully qualified and valid within the cluster?

Easy
44

A developer reports that a Service in the project `webapp` is not exposing the expected endpoints, even though the Deployment shows all replicas Running. The administrator inspects the Service and sees the selector is `app: web-frontend`. Which command should the administrator run to verify whether the Pods actually carry the labels the Service selector expects?

Medium
45

Which THREE network-related objects are namespaced in OpenShift? (Choose THREE)

Easy
46

Which THREE conditions must be met for a NetworkPolicy to successfully allow traffic from another pod? (Choose THREE)

Medium
47

An administrator needs to modify the timeout values for the default OpenShift Ingress Controller (Router). Where should this change be applied?

Medium
48

An administrator configures a LoadBalancer service on an OpenShift cluster running on a cloud provider. However, the EXTERNAL-IP remains in a <pending> state indefinitely. What is the most likely reason?

Medium
49

A cluster administrator needs to inspect the current default CNI network provider configured in an OpenShift 4.14 cluster. Which command or resource should the administrator check?

Medium
50

Which THREE troubleshooting steps should an administrator take when a newly created Route fails to resolve or connect? (Choose THREE)

Hard
51

An administrator needs to create a Route that handles multiple subdomains or redirects insecure HTTP traffic to HTTPS automatically. Where is the insecure traffic redirect configured?

Easy
52

An administrator needs to configure a custom default certificate for all routes created in the cluster without specifying a certificate on every individual Route object. Where should this wildcard certificate be configured?

Medium
53

Which THREE statements are true regarding Ingress controllers in OpenShift? (Choose THREE)

Medium
54

An administrator creates a NetworkPolicy that restricts egress traffic from a namespace. However, DNS resolution for external services immediately stops working. What is the cause of this behavior?

Hard
55

A cluster administrator notices that a NetworkPolicy applied to the database namespace is dropping traffic from the frontend namespace. The policy uses namespaceSelector. Which label must be present on the frontend namespace for traffic to be successfully allowed?

Hard
56

Which TWO of the following are valid Service types supported natively in OpenShift? (Choose TWO)

Easy
57

A developer reports that pods in the namespace 'project-a' cannot resolve services located in the namespace 'project-b' using standard internal DNS names. What is the correct way to query 'project-b' service 'backend' from 'project-a'?

Medium

Frequently asked questions

What does the Networking And Network Policies domain cover on the EX280 exam?
You must be able to expose an application with a Service and Route, and to write a NetworkPolicy that allows only specified pods on a given port while denying the rest. The critical detail is matching the correct podSelector and namespaceSelector labels so the policy actually selects the intended pods.
How many questions are in this domain?
This page lists all 57 Networking And Network Policies questions in the EX280 question bank. The actual exam draws from this domain proportionally to its weighting in the official exam blueprint.
What is the best way to practise this domain?
Start with a short focused session (10 questions) to identify gaps, then work through explanations. Repeat with a longer session once the weak areas feel solid.
Can I practise only Networking And Network Policies questions?
Yes — the session launcher on this page filters questions to this domain only. Choose any session length for inline explanations and scoring.
Red Hat Certified OpenShift Administrator (EX280, OpenShift Container Platform 4.14+) (EX280) Networking And Network Policies Practice Questions