BRIDGE NETWORKS

When you start Docker, a default bridge network is created automatically.

You can check this with "docker network ls".

The new containers connect to the default bridge unless otherwise specified.

You can create a CUSTOM BRIDGE NETWORK.

Differences:

CUSTOM BRIDGE NETWORK => automatic DNS resolution between containers.

BRIDGE:
Containers can only access each other by IP addresses.

CUSTOM BRIDGE NETWORK:
Containers can resolve each other by name or alias.

CUSTOM BRIDGE NETWORK => better isolation.

BRIDGE:
Containers without a --network specified are attached to the default bridge network, so other stacks/services/containers can communicate

CUSTOM BRIDGE NETWORK:
Only containers attached to that network can communicate

CUSTOM BRIDGE NETWORK => Containers easier to attach/detach.

BRIDGE:
To remove a container, you need to stop it and recreate it with different network options.

CUSTOM BRIDGE NETWORK:
You can attach/detach on the fly, during the lifecycle of the container.

CUSTOM BRIDGE NETWORK => Specific configuration for the services.

BRIDGE:
configurable, but needs a Docker's restart and all the containers use the same settings.

CUSTOM BRIDGE NETWORK:
Created/configured using docker network create.

Custom configuration for each service.

CUSTOM BRIDGE NETWORK => Better environment variables handling.

BRIDGE: Linked containers share environment variables.

CUSTOM BRIDGE NETWORK:
Containers connected effectively expose all ports to each other.

For a port to be accessible, that port must be published (-p flag)