In the previous chapter, we covered a bit of the Docker networking layout, so we will cover the main points here:

• By default, Docker containers run on an isolated virtual network on the host
• Each container has its own network address in that network
• By default, localhost for a container is not the host machine's localhost
• There is high overhead of manual work in order to connect containers manually
• Manual networking connections between containers are inherently fragile

In the parallel world of setting up a local server network, the base experience of Docker connectivity is very much akin to hooking up your whole network with static IPs. While this approach is not very difficult to get working, maintaining it is extremely hard and laborious, which is why we need something better than that.