What is a Firewall?
A firewall is a device that serves as a barrier between networks providing access control, traffic filtering, and other security features. Firewalls are commonly deployed between trusted and untrusted networks, for example between the Internet (untrusted) and an organization’s trusted private network. They can also be used internally to segment an organization’s network infrastructure, for example; deploying a firewall between the corporate financial information and the rest of the company network. Firewalls are additional security mechanisms that should be included in all networks, both wired and wireless, in addition to being implemented on client devices as software applications. With the increased risks that are associated with wireless networks, it is important to include firewalls and other security mechanisms during the design phase.
A firewall helps make your computer invisible to online attackers and blocks some malicious software such as viruses, worms, and trojans. A firewall can also help prevent software on your computer from accessing the Internet to accept updates and modification without your permission. Firewalls come in both software and hardware form, but hardware firewalls are intended for use in addition to a software firewall. Windows Vista and Windows XP both include a firewall. To learn more, read Understanding Windows Firewall. It is important to have both a firewall and antivirus software turned on before you connect to the Internet. Read more about firewalls.
A firewall is a system that is set up to control traffic flow between two networks. Firewalls are most commonly specially configured Unix systems, but firewalls have also been built out of many other systems, including systems designed specifically for use as firewalls. The most common commercial firewall today is CheckPoint FireWall-1, but competitors such as Cisco’s PIX are quickly catching up on CheckPoint.
A firewall is an important first line of defense for computer security. A firewall is software or hardware that acts as a barrier between your PC and the Internet. It prevents unauthorized programs or users from accessing your PC, and hides your Internet-connected PC from view. All information leaving and entering your PC must pass through the firewall. It ultimately helps keep hackers away from your personal and confidential data.
The Firewalls FAQ (»www.faqs.org/faqs/firewalls-faq/) defines a firewall as “a system or group of systems that enforces an access control policy between two networks.” In the context of home networks, a firewall typically takes one of two forms: Software firewall – specialized software running on an individual computer, or Network firewall – a dedicated device designed to protect one or more computers. Both types of firewall allow the user to define access policies for inbound connections to the computers they are protecting. Many also provide the ability to control what services (ports) the protected computers are able to access on the Internet (outbound access). Most firewalls intended for home use come with pre-configured security policies from which the user chooses, and some allow the user to customize these policies for their specific needs. More information on firewalls can be found in the Additional resources section of this document.
