Network Administration: Windows Firewalls
Windows includes a built-in firewall that provides basic packet-filtering firewall protection. In most cases, you’re better off using a dedicated firewall router because these devices provide better security features than the built-in Windows firewall does. Still, the built-in firewall is suitable for home networks or very small office networks.
Here are the steps that activate the built-in firewall in Windows XP or Vista:
Choose Start→Control Panel.
In the Control Panel, click the Windows Firewall icon.
This step opens the Windows Firewall dialog box. The figure shows the Windows Vista version.
Select the On (Recommended) option.
This option enables the firewall.
That’s all there is to it.
For Windows 7 or 8, the procedure is a bit different:
Open the Control Panel.
Windows 7: Choose Start->Control Panel.
Windows 8: Choose Settings->Control Panel from the Charms bar.
Click the System and Security link.
The System and Security page appears.
Click the Windows Firewall link.
The Windows Firewall page appears.
Click the Turn Windows Firewall On or Off link.
The page shown appears.
Select the Turn on Windows Firewall option.
Note that you can independently turn the firewall on or off for public network — that is, for your connection to the Internet — and for your home or work network — that is, if you have a network that connects other computers in your home or office.
Turn the firewall on for both or turn it off for both. Turn the firewall off if you’re using a separate firewall built into the router that connects your computer or home or work network to the Internet. Turn the firewall on if you don’t have a separate firewall.
Leave the Notify Me When Windows Firewall Blocks a New Program option enabled. That way, you’ll be notified when the firewall blocks a suspicious program.
The firewall is enabled.
Note that the firewalls included with Windows Vista and Windows 7 have additional options you can configure. However, don't fiddle with those options unless you’ve taken an upper-division college course in computer security.
Do not enable the Windows Internet firewall if you’re using a separate firewall router to protect your network. Because the other computers on the network are connected directly to the router and not to your computer, the firewall doesn’t protect the rest of the network. Additionally, as an unwanted side effect, the rest of the network will lose the capability of accessing your computer.