Open ports in any system are meant to accept network packets that can compromise the security of the computer to a great extent. For security issues, ports that are unused are generally closed by a firewall.
For users with systems based on the Windows or Linux platforms, it is possible to find out which ports are open. Once the command line interface in the in-console command prompt is inserted, the command will definitively reveal the list of open ports on the computer so that they can be secured.
Whether you're running Windows or Linux/Unix, the following command entered into the in-console command prompt will display the list of open ports on your computer: