Types of Docker Network Drivers

1. Bridge Driver

docker network create my-network
# By default this creates a bridge type network

The bridge network is the default network driver. If you don't specify a driver, this is the type of network being created.

We already saw this — when we created a custom network without specifying a driver, it defaulted to bridge type.

When is Bridge Used?

Bridge networks are commonly used when our application runs in a container that needs to communicate with other containers on the same host.

Types of Bridge Networks

1. Default Bridge Network

• Automatically created by Docker
• Used when no custom network is specified
• Containers need extra configuration to communicate

2. Custom Bridge Network

• Created manually by us
• Example:

docker network create my-network

Key Difference

In custom bridge networks:

• Containers can interact directly
• No need for IP addresses
• No need for manual port-based communication inside network
• Containers can use container names as hostnames

Real Example

This is how MongoDB and Mongo Express worked together:

• Both containers were added to the same custom bridge network
• Mongo Express connected to Mongo using container name (mongo)
• No external IP required

2. Host Driver

In the host network, the container uses the same network as the host machine.

Key Behavior

• Container does NOT get its own IP address
• Shares host machine’s network stack directly
• No network isolation

When is Host Used?

Use host networking when:

• We want maximum performance
• We want direct access to host network
• We don’t need isolation between host and container

Example

Container → Host Network → External Internet

3. None Driver

The none network provides complete isolation.

Key Behavior

• No network access at all
• No internet
• No container-to-container communication
• Fully isolated environment

Example

docker run --network none mongo

When is None Used?

Use it when:

• Security is critical
• No external communication is required
• Testing isolated environments

Creating a Custom Network

docker network create my-network

Verify Network Creation

docker network ls

Running Container in Custom Network

docker run -d \
  --name mongo \
  --network my-network \
  -e MONGO_INITDB_ROOT_USERNAME=admin \
  -e MONGO_INITDB_ROOT_PASSWORD=qwerty \
  mongo

Key Idea

• Container is now attached to my-network
• It can communicate with other containers in the same network
• It uses container names instead of IPs

Deleting a Network

docker network rm mongo-network

Verify Deletion

docker network ls

Now only default networks remain:

• bridge
• host
• none

Summary of Network Drivers

Key Takeaway

Docker networking determines how containers communicate:

• Bridge → Safe and most commonly used
• Host → Fast but no isolation
• None → Fully isolated environment

Custom bridge networks are the most important for real-world applications, especially microservices.