Absolute Beginners Guide to Upgrading and Fixing Your PC
| Connecting to the Internet is a two-way street your computer is connected to the global network, and the global network is connected to your computer. That means that not only can your PC access other computers on the Web, but other computers can also access your PC. If other users can access your computer, they can also take that opportunity to read your private data, damage your system hardware and software, and even use your system (via remote control) to cause damage to other computers. This risk is even more pronounced if you have an always-on connection, like that offered with DSL, cable modems, and other broadband providers. This is not an idle risk. Hackers can and do access household-based personal computers and are a real threat to the security of your system. Potential Threats
Just what kind of damage can be done by someone who hacks into your system? It's a long and scary list, including the following:
Is your computer at risk for these types of attacks? If you have a persistent broadband connection, the answer is yes. Without proper security, the typical PC connected via DSL or cable modem will be probed several times a day by potential hackers. It's hard to believe, but it's true; the odds are that your system will be hacked, unless you take the proper precautions. Protecting Your System with a Firewall
How do you protect your computer from unwanted intrusions? You could disconnect your computer from the Internet, but that wouldn't be very practical. A better solution is to install a software utility, called a firewall, that can ward off these uninvited attacks. A firewall is a software utility that forms a virtual barrier between your computer and the Internet. The firewall selectively filters the data that is passed between both ends of the connection, and protects your system against outside attack. Firewalls designed for home and small business PCs (so-called personal firewalls) work by trying to make your computer invisible to other computers on the Internet; if hackers looking for IP addresses don't see your PC's address, the odds of attack are decreased, thus decreasing your chances for attack. The firewall software does this by creating a type of proxy server. As shown in Figure 20.1, the firewall software acts as a type of virtual server that is inserted between your gateway PC and the Internet. The PCs in your home network interact with the proxy server, not directly with the Internet; the firewall acts as a gatekeeper, blocking access to your system by those computers that shouldn't have access. Figure 20.1. A firewall acts as a barrier between your home computer and the Internet.
Popular Firewall Software
PC-based firewall software is low cost, easy to install, and operates in the background whenever you start your computer and connect to the Internet. The best of these programs not only block unauthorized access, but also create a log of all computers that try to hack into your system and alert you of any successful attempts. Among the most popular firewall programs for the home are
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Using the Windows XP Internet Connection Firewall
If you're running Windows XP, you already have a firewall program installed on your system. You can make sure that Windows's Internet Connection Firewall is activated by following these steps:
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