How is network request routing inside Docker containers and between them implemented?

In Docker, each container gets its own network interface and IP address within the virtual Docker network (usually the default bridge network). Routing requests within a single container occurs through the local interface (localhost).

For communication between Docker containers, internal networks (bridge, overlay, etc.) are used. Containers in the same network can communicate with each other via IP or container name (if DNS resolution is enabled within the network).

Example:

• Containers are connected to the same bridge network.
• Container A communicates with container B by name or IP.
• Docker routes the request through the virtual bridge, directing packets to the appropriate container.

Additionally:

• External requests to containers usually go through port forwarding from the host to the container.
• For complex scenarios, custom networks and network plugins are used, which allow more flexible management of routing and isolation.

Thus, routing inside Docker is based on virtual networks and bridges, which provide isolation and the ability for containers to interact via IP and DNS names.