Adding Firewall Protection
After disabling file and printer sharing services, your next responsibility is to install a personal firewall to block unsolicited inbound traffic on the Internet connection. In Windows 2000, you must use a third-party product for this task because the operating system doesn't include any firewall features. In Windows XP, you can use a third-party product, but you remain perfectly secure with the help of the built-in ICF. We explain the ins and outs of firewalls in Blocking Attacks with a Firewall, so we won't repeat those details here. In this section, we focus instead on how to work around some of the occasionally confusing choices that the Windows XP Network Setup Wizard offers when you add an Internet connection to your LAN.

To start the wizard, open the Network Connections folder and choose File, Network Setup Wizard. After you click through its two introductory screens, the wizard displays the dialog box shown in Figure 15-2. The first two options assume that you're sharing an Internet connection over your network using either a hardware router or a computer running Internet Connection Sharing software. As we explain later in this chapter, this is indeed the safest and simplest way to add Internet access to a LAN.


Figure 15-2. If your computer is connected directly to the Internet and a LAN, choose the Other option.
If your computer has both a direct physical connection to the Internet and a LAN connection, choose the Other option and click Next. In the Other Internet Connection Methods dialog box, shown in Figure 15-3, select the top choice, This Computer Connects To The Internet Directly Or Through An Internet Hub, and click Next to continue.


Figure 15-3. If other network users are not accessing the Internet through your computer, choose the top option from this list.
The wizard next presents a list of available network connections, making its best guess as to which one represents the connection to the Internet. Confirm that the Internet connection is selected (in the example shown here, we've made identification easier by giving each network connection a descriptive name) and click Next to continue.


Before completing its task, the wizard displays the dire warning shown in Figure 15-4.


Figure 15-4. If your Internet connection is firewalled and you're confident that no other network computers have Internet access, you can proceed despite this warning.
Although the warning is generally accurate, you may safely disregard it and continue if you meet either or both of the following conditions:

You are certain that no other computer on your network has an active Internet connection or that all other Internet connections are protected by a firewall.
You have disabled the TCP/IP protocol on your LAN connection and are using a non-routable protocol such as IPX/SPX or NetBEUI.
If there is any chance that another computer on your network can connect to the Internet without the protection of a firewall, you run the risk that an intruder can break in to that computer and then access resources on your computer using your TCP/IP-based LAN connection. If you're confident this can't happen, click Next and finish the wizard. After prompting you for the computer and workgroup names, the wizard enables the ICF on the Internet connection but leaves the network connection open so that you can share resources across your local network.

Libellés : Adding, Firewall, Protection