Firewalls can do a lot for your site's security. In fact, some advantages of using firewalls extend even beyond security, as described below.Think of a Firewall as a choke point. All traffic in and out must pass through this single, narrow Checkpoint. A Firewall gives you an enormous amount of leverage for network security because it lets you Concentrate your security measures on this Checkpoint: the point where your network connects to the Internet. There are different layers of a security framework. To start with, there is the physical layer. This alludes to the genuine equipment. At the point when the framework is firewalled genuinely, there is no association with outside systems. While this strategy can be viable, it is constraining and not as adaptable or quick as different strategies.The second sort of Firewall layer is the application type. This is at the product level where bits of code figure out what sort of data is going through.
This sifting is done by means of a procedure known as bundle separating. Focusing your security in this way is far more efficient than spreading security decisions and technologies around, trying to cover all the bases in a piecemeal fashion. Although firewalls can cost tens of thousands of dollars to implement, most sites find that concentrating the most effective security hardware and software at the Firewall is less expensive and more effective than other security measures - and certainly less expensive than having inadequate security.
MOre info @ types of network security