Choosing a Hardware or Software Firewall

Look for a hardware firewall that provides Network Address Translation (NAT). NAT hides your network from outsiders by handling requests on your network for data from the Internet then passing it on to the correct computer within your network (but not letting any requests come from outside your network).

A software firewall, such as those made by McAfee, Symantec, and Zone Labs, can also keep data from going out of your network onto the Internet (Figure 12.2). Software routers are sometimes called personal firewalls because they are installed at each machine (you don't need a network to use a personal firewall).

Figure 12.2. A software firewall protects an individual PC from unauthorized access over the Internet.

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Why would you want to scan requests for data from within your network? Some viruses that work their way onto your computer can do their worst damage once they start sending information from your computer, which then allows them to continue to spread as recipients open e-mail attachments they see as a trusted sourcenamely, you.

Software firewalls can offer protection against e-mail viruses, which send data from your computer over the Internet (Figure 12.3).

Figure 12.3. Zone Lab's Zone Alarm can keep softwareor a viruson your computer from contacting the Internet without your permission.

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Software firewalls can also alert you to "spyware" activity on your computer. Spyware is software downloaded onto your computer, sometimes without your knowledge, which connects to its maker and reports back information from your PC. Spyware is often bundled with software you download, and installs without your knowledge. Typically, spyware can't identify you uniquely, but the software will attempt to contact its maker to collect aggregated user information. With a software firewall, you get to decide what programs can send data from your computer over the Internet, even if they are transparently working in the background.

The Internet security suites offered by McAfee and Symantec, combine antivirus software with personal firewalls and also offer intrusion detection ( ID ). Intrusion detection can alert you to the presence of a hacker who might be deleting files, for example, or accessing directories in the background without your knowledge.

ID acts as a second line of defense, for instance, if your antivirus software did not catch a Trojan horse. A Trojan horse is a program that appears to be safe, or useful, but instead installs malicious code on your system. A Trojan horse could allow a hacker to control your computer surreptitiously over the Internet. If you should suffer a Trojan horse, your ID software can alert you that actions are being taken by your computer that you did not authorize.



Complete Home Wireless Networking. Windows XP Edition
Complete Home Wireless Networking. Windows XP Edition
ISBN: N/A
EAN: N/A
Year: 2002
Pages: 118

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