Docker Networking

Docker’s networking subsystem is pluggable, using drivers. Several drivers exist by default and provide core networking functionality.

Core Network Drivers

1. bridge (Default): The default network driver. If you don’t specify a driver, this is the type of network you are creating. Bridge networks are usually used when your applications run in standalone containers that need to communicate.
2. host: Removes network isolation between the container and the Docker host, and uses the host’s networking directly. The container does not get its own IP-address allocated. For instance, if you run a container that binds to port 80 and you use host networking, the container’s application is available on port 80 on the host’s IP address.
3. none: For this container, disable all networking. Usually used in conjunction with a custom network driver.
4. overlay: Connects multiple Docker daemons together and enables swarm services to communicate with each other. This is for multi-host networking.
5. ipvlan / macvlan: Give you direct control over IPv4 and IPv6 addressing, allowing you to assign a MAC address to a container, making it appear as a physical device on your network.

Key Networking Concepts

• DNS Resolution: Docker has a built-in DNS server that allows containers on the same user-defined network to resolve each other by name.
• Port Mapping: -p 8080:80 maps port 8080 on the host to port 80 in the container.