What is Docker Network?

A Docker network is a virtual connection that allows containers to communicate with each other.

Without a network, containers are isolated and cannot talk to each other. With a network, they can reach each other using container names as hostnames — no IP addresses needed.

Why Do We Need It?

Real scenario — you have two containers:

Without network: Web App cannot reach Database.

With network: Both are connected and talking using container names.

Basic Network Commands

# Create a network
docker network create my-network

# List all networks
docker network ls

# See details of a network
docker network inspect my-network

# Delete a network
docker network rm my-network

# Delete all unused networks
docker network prune

Three Names to Understand

This is the most confusing part. Every docker run command has three different names:

docker run -d --name CONTAINER-NAME --network NETWORK-NAME IMAGE-NAME
Name What it is Who decides
Container Name Name of the running container, used as hostname You
Network Name The network both containers must share You
Image Name The blueprint to run (Docker Hub or your build) Docker Hub or you

Example:

docker run -d --name mongo-container --network my-net mongo
#                    ↑                      ↑          ↑
#             Container Name          Network Name  Image Name