What is a Firewall ?

Firewall

Firewall is basically a defense system that blocks intruders on the internet from gaining access to your computer network. It acts as a "wall" that restricts the movement of data between the internet and your network, and vice-versa. Firewalls can be implemented via either hardware or software, or both.

Use:
A firewall serves two primary purposes. First, it protects computer systems and networks from malicious activity coming across internet connections. Second, it also provides computer network administrators with control over the types of communication that can be conducted over internet connections within a specific computer network. In the first purpose, the firewall acts as a communications filter which can stop those malicious communications from ever reaching your computer in the first place. The second purpose is where a firewall can be programmed with specific, customized rules that may restrict employees from visiting websites that are unrelated to business goals or that may pose security risks.

How It Works

There are basically two types of firewalls, these are hardware firewalls and software firewalls. A hardware firewall is a physical device that is installed between the modem and computer. A software firewall, however, is a software application that is installed onto the computer system that you wish to protect and this is usually the computer with the modem attached to it. 
Most firewalls maintain lists of rules for filtering data and of characteristics of both "safe" and "unsafe" data.  All messages entering or leaving the intranet pass through the firewall, which examines each message and blocks those that do not meet the specified security criteria. If an incoming packet of information is flagged by the filters, it is not allowed through.  The filters can be customized to restrict information and communication in a number of ways. One of the more sophisticated customization settings is the ability to ban content by certain words or phrases. This option is sometimes used by companies to prohibit their employees from accessing certain websites that would be inappropriate for the workplace. A firewall can also be used to block access to specific websites, such as popular personal email sites or even specific IP addresses.
Shantanu

Posted in: Internet