Network drivers (bridge, host, overlay, none) in Docker - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Docker bridge network

Which statement best describes the Docker bridge network driver?

A It disables all networking for the container, isolating it completely.

B It connects containers directly to the host's network stack, sharing the host IP address.

C It creates a private internal network on the host where containers can communicate, isolated from the host network.

D It allows containers to communicate across multiple Docker hosts using an overlay network.

💡 Hint

Think about a private network inside the host for containers.

The bridge driver creates a private network internal to the host. Containers on this network can talk to each other but are isolated from the host network unless ports are published.

💻 Command Output

intermediate

Output of docker network inspect for host driver

What is the key difference in the output of docker network inspect host compared to a bridge network?

Docker

docker network inspect host

A The output shows an overlay network with multiple nodes connected.

B The output lists multiple IP addresses assigned to containers on a private subnet.

C The output indicates the network is disabled with no interfaces.

D The output shows containers share the host's network namespace with no IP address assigned to the network.

💡 Hint

Host network means no separate network namespace for containers.

The host network driver makes containers use the host's network stack directly, so no separate IP or subnet is assigned.

🔀 Workflow

advanced

Setting up multi-host communication with overlay network

Which sequence of commands correctly sets up an overlay network for containers across multiple Docker hosts?

A 3,1,2,4

B 1,2,3,4

C 2,1,3,4

D 1,3,2,4

💡 Hint

Initialize swarm before creating overlay network and joining nodes.

First, initialize swarm on manager (1), then create overlay network (2), join worker nodes (3), and finally deploy service on overlay (4).

❓ Troubleshoot

advanced

Diagnosing container network isolation with none driver

A container started with --network none cannot access the internet or other containers. What is the reason?

A The none driver disables all networking, so the container has no network interfaces.

B The container is connected to a private bridge network with no internet access.

C The container shares the host network but firewall blocks traffic.

D The overlay network is misconfigured causing isolation.

💡 Hint

None means no network at all.

The none network driver disables networking completely, so the container has no network interfaces and cannot communicate.

✅ Best Practice

expert

Choosing the right network driver for a secure web app

You want to deploy a web app container that must be isolated from other containers but accessible from the host on port 8080. Which network driver and configuration is best?

A Use bridge network and publish port 8080 to host, isolating containers but allowing host access.

B Use host network to share host IP and ports directly for best performance.

C Use none network and manually configure port forwarding on host.

D Use overlay network without publishing ports for container isolation.

💡 Hint

Isolate containers but allow host access on a port.

The bridge network isolates containers by default. Publishing port 8080 allows host access without exposing containers to each other.