Docker Publish Port

By default Docker does not expose Container's Port to the Host, to do so we can --publish or -p flag, which exposes Container's Port(s) to Host.

Example

$ docker run -d -it \
           -p 43210:43210/udp \
           --name bombsquad \
           crazyuploader/bombsquad

Here, we're exposing UDP Port 43210 to the Host.

Source: Docker Docs