A firewall is a network security system that manages the incoming and outgoing traffic in our system. It restricts networks that do not have access to certain parts of our system. It protects our systems from unknown networks and gives access to only those networks that satisfy the security rules.
Here is a Do It Yourself:
Try blocking the access of any application on your system by performing the following steps:
1) Open your firewall and go to Internet connections for programs.
2) Select the application that you wish to block. For example, I want to block Firefox on my system.
3) Change the access from incoming and outgoing to block. Save the edits.
4) Now, you won't be able to access the application.
