Is There a Proticle That Should Never Escape Your Network?

Shodan io is a web sight that scans the entire inner net to see if any well known ports are opened, and makes that data base searchable for any one to see. Its goal is to help us be aware of how insecure the innernet is. He found that printers often listen on three points, and if these ports were exposed to the internet, it may mean that someone can print to that machine from anywhere in the world. There was zero planning in this ous. Just just trying to have some fun. And i think the most dangerous thing is a board hacker.