What Is a Firewall?
An Internet firewall can help prevent outsiders from getting to your computer through the Internet. Firewalls come in two forms, software or hardware, and they provide a protective boundary that helps screen out unwanted Internet invaders.

Why Do I Need a Firewall?
A firewall can screen for malicious Internet traffic such as hackers, worms, and certain types of viruses before they can cause problems on your system. In addition, firewalls can help keep your computer from participating in attacks on others without your knowledge. Using a firewall is especially important if you are always connected to the Internet, such as when you have a broadband cable or digital subscriber line (DSL or ADSL) connection.

How Do I Start Using a Firewall?
A firewall is built into Microsoft Windows® XP. You can get started today by using the Windows XP Internet Connection Firewall feature. In most cases, the steps on the Protect Your PC page help you to enable the Internet Connection Firewall in Windows XP and should be used if you have a single computer that you connect to the Internet. Several additional firewall options are available to you, including software and hardware solutions. You might want to consider these if you have an earlier version of Windows, encounter compatibility issues with the Windows XP firewall, or want to consider a firewall package with different features for use with Windows XP.

Firewall Options
Versions of Windows before Windows XP did not come with the Internet Connection Firewall. If you have a computer with an earlier version of Windows, and it is connected directly to the Internet or public network, you should purchase a firewall and use it.

How Can I Tell Which Version of Windows I'm Running?

Windows XP users who want different features in a firewall may also use a hardware firewall or a software firewall from another company. In some situations, advanced users may choose to use both software firewalls and hardware firewalls on their networks.

The following resources provide more information about firewall options.

Hardware Firewalls
Hardware firewalls are a viable alternative if you are using an earlier version of Windows. Many wireless access points for home networks are available as all-in-one combination units that have integrated hardware firewalls along with broadband routers. Wiring a firewall into your network can be as simple as adding an answering machine to your telephone line. Simply unplug the Ethernet connection between your cable/DSL modem and your PC, and plug in the firewall in between. (This works for most, but not all, firewalls.)

Software Firewalls
Software firewalls are available from several vendors, which you can add to help protect your computer running an earlier version of Windows. These vendors also offer firewalls that you can use with Windows XP. These vendors include:

 

 

 

 

 

Checklist: Install a Firewall
This easy-to-follow article from the Microsoft Security site includes a discussion of software firewalls made by other companies, as well as hardware firewalls and network routers. This information can help you select a firewall solution if you use an older version of Microsoft Windows, such as Windows 2000, Windows Millennium Edition (Windows Me), Windows 98, Windows NT®, or Windows 95.

TechNet Article: Firewalls
This article on firewalls from the Microsoft TechNet site includes a more advanced discussion of firewall options for home and small office users.

Sophos Anti-Virus is provided for King's College Faculty, Staff and Students at no cost.