How to open a port in ubuntu?

Question

ubuntu

Guys please tell me how to open port 8080 in ubuntu? the server is DMZed, but when running a node js application on 8080, the socket cannot connect

Answer 1

By default, ports in Ubuntu, as in almost any distribution, are open .
Make sure nothing else is occupying port 8080 on your server.
sudo netstat -tulpn

Answer 2

As in any other distribution:
Or, the server does not run on ANY, but on the localhost.