After reading the latest posts a bit better, this is how it works with docker networks (I’m writing it extra clear so everyone no matter the amount of knowlage will understand):
You can see each container as its own computer on a network. Each container will get their own IP address that the Docker Bridge provides (You can use the network “host” and then the container will use your computers IP address). You can see the Docker Bridge as a virtual domain host. It takes care of all networking within Docker.
For each container you can specify a network. These networks will get their own sub-network (192.168.XX.0 in my case) and all containers within that network will live under that sub-network (192.168.80.1, 192.168.80.2 etc). As these containers now live under the same sub-network they can access each other with their hostname (this will be the containers name) or their docker-ip.
A container can have multiple networks attached to it. It will use the first networks sub-network-range but it will be able to access all other countainers from the other networks.
For containers outside a network you can only access it through the docker bridge, meaning your computer’s IP address + the published port.
The power of having everything on different networks is that containers only access what they need to access on the network. Eg Ayon doesn’t need to have access my Kitsu’s database but it needs to access the Kitsu webhost and the Kitsu webhost have access to the database.
So if your computer/server that’s running Docker have a static IP on your network or a known hostname you will always be able to access your containers through its ip/hostname + the containers port within other containers. If they share networks you can simply enter the containers hostname and (most of the times) skip any port numbers.