What is Docker Networking?

Question

Accepted Answer

**Docker Networking** — container communication and network isolation.

```bash
# Network types
docker network create mynetwork
docker network create --driver bridge --subnet 172.20.0.0/16 mynet
docker network create --driver overlay --attachable myoverlay
docker network create --internal myinternal

# Connect containers
docker run --network mynetwork --name web nginx
docker run --network mynetwork --name app myapp
docker network connect mynetwork existing_container
docker network disconnect mynetwork existing_container

# Inspect
docker network ls
docker network inspect mynetwork
docker network prune  # Remove unused

# DNS resolution within network
docker exec web ping app  # Resolves by container name

# Port mapping
docker run -p 8080:80 nginx           # host:container
docker run -p 127.0.0.1:8080:80 nginx  # specific host
docker run -P nginx                      # random host port
```

```yaml
# docker-compose.yml networks
services:
  web:
    networks:
      frontend:
        aliases: [web.local]
      backend:
  db:
    networks:
      backend:
        ipv4_address: 172.20.0.10

networks:
  frontend:
    driver: bridge
  backend:
    internal: true
    driver: bridge
```

**Network Drivers:**
- bridge: default, host communication.
- host: share host network.
- overlay: multi-host (Swarm).
- macvlan: direct MAC assignment.
- none: no networking.

DevOps: What is Docker Networking?