Container Networking

Containers rarely run in isolation — they need to communicate with each other, with the host, and with the outside world. This lesson covers Docker's networking model, network drivers, port mapping, DNS resolution, and network isolation strategies.

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Docker Network Drivers

Docker provides several built-in network drivers, each suited to different use cases.

Driver	Description	Use Case
bridge	Default; isolated network with NAT to host	Single-host container comms
host	Container shares the host's network namespace	Maximum network performance
none	No networking at all	Maximum isolation
overlay	Multi-host networking (Swarm/Kubernetes)	Cross-host container comms
macvlan	Assigns a MAC address; container appears on physical LAN	Legacy apps needing direct LAN

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The Default Bridge Network

When you start a container without specifying a network, Docker connects it to the default bridge network.

# Run two containers on the default bridge
docker run -d --name web nginx:alpine
docker run -d --name api node:20-alpine sleep 3600

# Inspect the default bridge network
docker network inspect bridge

Limitations of the Default Bridge