How Does A Firewall Work?

A firewall is essentially a common information technology (IT) security device that is configured such that it permits, denies or even proxy data connections set. It is configured as per the organisation's security policy. You will find diverse firewalls. They can be hardware and/or even software based.

First generation firewalls were essentially packet filters while second generation ones were "stateful" filters. Third generation firewalls are application layer firewalls. There have been a number of subsequent developments.

For instance, a proxy device (which runs on dedicated hardware or even as software found on a general-purpose machine) possibly can act as a firewall via responding to various input packets (such as connection requests, for instance) in the way an application would, whilst blocking other packets. Microsoft Internet Security and Acceleration Server would be one such server which acts as a proxy server in addition to a firewall. This product is designed to runs on both Windows 2000 and 2003 servers

Visit computer.howstuffworks.com for details on how firewalls work.