FROM node:alpine
COPY ./ ./
RUN npm install
CMD ["npm", "start"]

If this is your Dockerfile and your node app starts at port 8080, then logically you would think that typing

http://localhost:8080

would give you access to the application. This works fine on OSX, but on a Windows 10 machine using Docker Toolkit, you will get an error message which says, that the browser can’t establish a connection to the server at localhost:8080.

The logical step would be to check the hosts file and uncomment the line for

# localhost name resolution is handled within DNS itself.
127.0.0.1       localhost

Still it will not connect. Few other suggestions are to try one of the following

http://0.0.0.0:8080   
http://127.0.0.1:8080  .

If both of these don’t work, the sure shot way is the following. Type docker-machine ls and note the NAME of your instance

$ docker-machine ls
NAME      ACTIVE   DRIVER       STATE     URL                         SWARM   DOCKER        ERRORS
default   *        virtualbox   Running   tcp://192.168.99.100:2376           v17.06.0-ce</code></pre>

Following this get the IP address of your instance with

$ docker-machine ip default
192.168.99.100

Once you have the IP address of your instance, you can type

http://192.168.99.100:8080 

and access your instance.