How are you currently running the container? If you're using docker run ... could you try instead using docker run -d ... - this should run the container as a background process.
If you then run docker ps -a you should be able to see a list of containers and which ports are being exposed/forwarded to. You should see something like 0.0.0.0:8000->8000/tcp for your container. If you don't see that, could you post the output line of docker ps -a relating to your container here?