This type of network just puts the container in the host's network stack. That is, all of the network interfaces defined on the host will be accessible to the container, as you can see in the following diagram:
If you start your container using the -net=host option, then the container will use the host network. It will be as fast as normal networking: there is no bridge, no translation, nothing. That's why it can be useful when you need to get the best network performance. Containers running in the host's network stack will achieve faster network performance compared to those running on bridge networking, there is no need to traverse ...
