Docker --net=host does not forward ports

On my local machine setting --net=host on a container makes the container visible on any ports it is using. On a Docker Ubuntu 16.04 droplet the port is not accessible with --net=host.

Simplified Example:

This works: docker run -p 8000:8000 -it python python -m http.server

This does not work: docker run --net=host -p 8000:8000 -it python python -m http.server

How can I make the ports of the container application exposed with docker run --net=host ...?