As today’s businesses increase in sizes, there is a more demanding need for an increase in security needs. Many businesses today have to answer the question of, “When do I know that have too much security and which network system is more secure for my company?” To answer this question many points of views have to immerge with the best compatible solution. Companies should consider involving many systems such as cost management, and security management system. Companies don’t want to have too much security when the solution cost more than the problem in money or time. Under these aspects if companies want to start a new system, which I’m considering here two major operating systems such as Windows NT, and Linux by give them close look for how they are operating and what are they using in their security system to insure businesses and companies securities and how are they reducing security threats.The concerns about security of an organization is not directly depend on the data communication related areas but also the control mechanism which implements, restricts and protects the threats from in and out side the organization. In our age of decaying morals, we find the need for security in every aspect of life. There are far to many people that are willing and able to take anything they can that doesn't belong to them. We have security everywhere we look. There are armed guards in our stores and even schools. Police officers patrol the streets trying to keep people safe. We have people to provide security in a world where things are physical, but what to we do in a computer world, where what we want to keep safe is information? This is where computer security comes into play. Security is defined as the combination of all mechanisms, which allow only authorized people to use the resources they are supposed to. These can be locks, people or physical barriers that stand in the way of a desired l...