Understanding Docker Network Drivers (and When to Use Them)

Have you ever created a container and wondered how it communicates? Well, networking inside Docker can be a little challenging, but don’t worry; there aren’t many concepts you will need to know. In this article, I cover understanding Docker network drivers and, more importantly, when to use them.

There are various network drivers available in Docker, but there are four common network drivers: bridge, host, overlay, and none. Here, we look at each one using practical examples.

Bridge: Default Option for Everyday Work

When you don’t define a network, then Docker chooses bridge as the default option. Using bridge, it creates a virtual internal network that allows containers to communicate with each other.

docker run -d -p 8080:80 nginx

In this example, the container runs on an internal IP, and port 80 inside the container is mapped to port 8080 on your machine.

If you want containers to communicate by name, create your own bridge network:

docker network create my-app
docker run -d --network my-app --name web nginx

This is perfect for local development and multi-container apps using Docker Compose.

Host: Direct Access to the Machine

With a host network, the container completely eliminates any network isolation, as the host driver is involved. As a result, the container utilizes the network stack of the host system.

docker run --network host nginx

In other words, there is no need for port mapping, as the IP addresses of the containers are the same as those of the host system.

Although it provides certain performance improvements, this method does not provide any isolation or port conflict resolution capabilities.

Overlay Network: Communication Between Multiple Hosts

When your application is hosted across several servers, overlay networks come into play. The network enables communication between containers from various servers by allowing them to connect and behave as if they were part of the same network.

docker network create -d overlay my-overlay

An overlay network is a widespread concept in Docker Swarm or similar applications. After connecting, the containers will be able to communicate without additional configuration.

The internal workings are taken care of by Docker, and there is no need for any additional steps.

None: Complete Isolation

The none driver disables networking entirely.

docker run --network none busybox

This container is not connected to any external systems and is not capable of communicating with other containers. It possesses a loopback device only.

This is quite useful when working on tasks that require no network access at all.

Learn More About Docker Networking

Understanding Docker network drivers is a key skill you will need as a developer. To learn more about Docker networking, you can go to my course on LinkedIn Learning, Docker Networking: Creating, Managing, and Troubleshooting Container Networks.