In earlier chapters, we were exposed to the concept of ICC mode, but didn't have much information on the mechanics of how it worked. ICC is a Docker-native way of isolating all containers connected to the same network. The isolation provided prevents containers from talking directly to each other while still allowing their exposed ports to be published as well as allowing outbound connectivity. In this recipe, we'll review our options for ICC-based configuration in both the default docker0 bridge context as well as with user-defined networks.
We'll be using two Docker hosts in this recipe to demonstrate how ICC works in different network configurations. It is assumed that both Docker hosts used in this lab are in their default configuration. In some cases, the changes we make may require you to have root-level access to the system.