Docker Networking Explained: Bridge, Host, and Overlay Networks in Practice

Docker containers on separate networks cannot communicate by default, but creating a custom bridge network enables built-in DNS resolution so containers can reach each other by name. The default bridge and host networks do not support container name resolution, making user-defined networks essential for multi-container setups. Host networking removes network isolation entirely, allowing containers to share the host machine's network interface without port mapping, though this limits port availability. Overlay networks extend connectivity across multiple machines and require Docker Swarm or a cluster to function. For most everyday use cases, a custom bridge network is sufficient, while host and overlay networks serve specific performance or multi-host scaling needs.