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Step 3 - Set Up a Firewall

A firewall is software or hardware that helps stop hackers, viruses, and other threats from reaching your computer over the Internet. Installing a software firewall on every computer in your office is an effective and important step you can take to help protect your computers. Consider installing a hardware firewall device if you operate a network because these devices can protect all the computers on your network.

Key point: Have your firewall and antivirus software turned on before you ever connect to the Internet.

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More about firewallsMore about firewalls
How the Windows Firewall worksHow the Windows Firewall works
Windows Vista firewall improvementsWindows Vista firewall improvements
Another option: Windows Live OneCareAnother option: Windows Live OneCare

More about firewalls

A firewall screens information coming to your computer over the Internet or from another network. It helps block suspicious and unauthorised attempts by people or programs (including viruses and worms) that try to connect to your computer. A firewall performs its job by controlling what data can come across the different "ports" that your computer uses to communicate over the Internet. (Think of a port as a door for a specific type of network traffic such as instant messaging or e-mail.)

A firewall is different from antivirus software, but the two work together to help protect your computer. If your computer was a house, you might say that a firewall guards the windows and back doors against strangers or unwanted programs trying to get in. An antivirus program protects against viruses or other security threats that try to sneak in through the front door. For instance, antivirus software can protect you against e-mail viruses attached to e-mail messages but a firewall will not.

How the Windows Firewall works

The Windows Firewall is a software firewall built into Windows Vista and Windows XP Service Pack 2 (SP2) and is turned on by default. It creates a protective boundary that monitors and restricts information that travels between your computer and a network or the Internet.

Here are a few scenarios that describe how the Windows Firewall works:

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When someone on the Internet tries to connect to your computer, the Windows Firewall will treat it as an "unsolicited request." The firewall prevents all unsolicited traffic from reaching your computer by blocking the connection.

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When you run a program that needs to receive information from the Internet or a network (such as instant messaging), the Windows Firewall will ask if you want to block or unblock (allow) the connection. If you choose to unblock the connection, Windows Firewall creates an exception so that it does not alert you again when that program needs to receive information.

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The Windows Firewall will dynamically open ports and allow your computer to receive traffic that you have specifically requested, such as a Web page you ask your browser to retrieve.

By default, the Windows Firewall opens only the ports for the most common Internet traffic such as e-mail and Web browsing. Programs that may initially be blocked include file sharing and file transfer software, remote desktop-sharing programs, and file sending through instant messaging programs.

The Windows Security Centre in Windows Vista and Windows XP lets you know if the Windows Firewall is turned on. If there is an issue with your firewall, Windows Security Centre notifies you and provides guidance to help you correct the problem. Figure 1 shows firewall monitoring in the Windows Vista Security Centre.

Figure 1: Windows Vista Security Centre

Figure 1: Windows Vista Security Centre

Windows Vista firewall improvements

The Windows Firewall that comes with Windows Vista includes some significant improvements. For instance, you have the ability to block connections to the Internet from your computer as well as to your computer. This means you can filter traffic outbound from your computer generated by spyware and viruses thereby preventing the malware from spreading to other users.

Another option: Windows Live OneCare

Windows Live OneCare is a comprehensive Microsoft security service you can subscribe to that also includes a two-way managed firewall. This means that both inbound and outbound traffic is controlled. The firewall is also updated continually to help protect you. Visit the Windows Live OneCare site for more information and to sign up for a free trial.

Note that the Windows Firewall does not conflict with Windows Live OneCare firewall and does not need to be removed when using the service.


Seven Steps to Better Security

1. Update Your Software
2. Install Virus and Spyware Protection
3. Set Up a Firewall
4. Back Up Your Data
5. Guard Against Computer Theft
6. Secure Your Private Network
7. Create a Security Plan

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A router that connects multiple computers in your office to the Internet is an example of hardware that offers firewall protection. You should use your Windows Firewall in conjunction with any hardware firewall that you install.