Docker Port Mapping

When you create or run a container using docker create or docker run, it does not expose any of its ports to the outside world. To make a port available to services outside of Docker we use the --publish or -p flag. This creates a firewall rule which maps a container port to a port on the Docker host to the outside world. 

-p 8080:80 Map TCP port 80 in the container to port 8080 on the Docker host.

-P Publish all exposed ports to random ports

This means that if any request comes to port 8080 of the docker host, it will route it to port 80 of the container.

Let’s understand this with an example:

Suppose my local host’s ip is And NGINX container IP is So with port mapping, we want to achieve-

Traffic from to go to

Run the below command to map the port-

learning-ocean:~ gaurav$ docker container run -itd -p 3600:80 nginx
learning-ocean:~ gaurav$

Let’s try to access the NGINX with HostIP:Port


This way, we can expose our containers to the outside world.