A firewall is a program or device that acts as a barrier to keep destructive elements out of a network or specific computer. Firewalls are configured (in hardware, software, or both) with specific criteria to block or prevent unauthorized access to a network. Firewall helps screen out hackers, viruses, and worms that try to reach your computer over the Internet..
If you use a computer at home, the most effective and important first step you can take to help protect your computer is to turn on a firewall. If you have more than one computer connected in the home, or if you have a small-office network, it is important to protect every computer. You should have a hardware firewall (such as a router) to protect your network, but you should also use a software firewall on each computer to help prevent the spread of a virus in your network if one of the computers becomes infected. If your computer is part of a business, school, or other organizational network, you should follow the policy established by the network administrator.Software Development Next