Chapter 31: Network and Internet Security

Enabling the Internet Connection Firewall Between Your PC and the Internet

Some people say the Internet is an evil place filled with miscreants, while other people say the Internet is one of the safest places anyone can be. Neither group is right, but are more likely to be fulfilling some politically charged agenda. While the Internet contains pornography and social aberration, it also provides clean and wholesome fun for all who want it. However, there is still a dark side to the Internet, and you need to protect your computer (and yourself) from it.

A cracker is a programmer whose goal is to exploit gaps in Windows security to gain access to your files, take over your computer, or simply crash it. Fortunately, Microsoft has provided some protection against such malicious programmers by adding Internet Connection Firewall to Windows XP.

A firewall is a program that stands between your computer (or your LAN) and the Internet. Each packet on the Internet is addressed to a specific port number on a specific computer. Each computer connected to the Internet "listens" to packets addressed only to certain ports. As a general rule, most people use only a few ports: 21 (for FTP, or file transfer), 25 (for outgoing e-mail), 80 (for Web pages), 110 (for incoming email), 119 (for newsgroup messagess), and sometimes 443 (for secure connections).

The Internet Connection Firewall (ICF) controls what ports are open, refusing to respond to packets addressed to other ports. We recommend that you enable the Internet Connection Firewall on all your Internet connections. Follow these steps:

1. Open the Network Connections window (choose Start | Control Panel | Network And Internet Connections | Network Connections).
2. Click the Internet connection.
3. Click Change Settings Of This Connection in the Network Tasks listed in the Task pane. You see the Properties dialog box for the Internet connection.
4. Click the Advanced tab. You see the Internet Connection Firewall and Internet Connection Sharing settings.
5. Select the Protect My Computer And Network By Limiting Or Preventing Access To This Computer From The Network check box.
6. Click OK to put the changes into effect.

Once you have enabled the Internet Connection Firewall, go to Steve Gibson's Web site at http://grc.com, click the link to his Shields Up free firewall-testing service, and follow the directions on the Web page. Shields Up can tell you whether the firewall is working correctly.

MSN Explorer May Compromise Security MSN Explorer is a program that works with Internet Explorer and provides access to a bunch of MSN services like Hotmail. It's pretty cute. But we found the following line in the MSN Explorer Security Statement:

If you have chosen security settings that will interfere with MSN Explorer, then your security settings are temporarily changed to allow MSN Explorer to work properly. In addition, while MSN Explorer is active on your computer, the special settings for MSN will apply to any Microsoft Internet Explorer window you may have open.

If Internet security is important to you, you may prefer to forego using MSN Explorer.