There are multiple ways for Docker containers to communicate: 1) direct communication via container IP (within the same network); 2) DNS resolution via container name (Docker built-in DNS); 3) using --link parameter (deprecated, not recommended); 4) sharing network namespace (using --network container:container_name); 5) using external services (such as Nginx reverse proxy). Best practice is to create custom networks (docker network create) and add related containers to the same network, so they can access each other by container name with better network isolation. Overlay networks support cross-host container communication and are suitable for Swarm cluster environments.