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Appendix B Computer Security
Internet Browsers
Always exit the Internet browser (for example, Internet Explorer or Netscape
Navigator). Never “minimize” the browser or leave it open in the background.
Breaking into a computer is easier when an Internet browser is running.
Network Applications
Network applications (such as software programs) that allow remote access to
the computer also make the computer vulnerable to access from other people on
the Internet. If using a network application that allows remote access, consider
installing a firewall.
Electronic Security
Here are two methods to secure your computer electronically.
Network Address Translation
If a local area network and a PPP connection to the ISP using dynamic IP
addresses through a DHCP server are being used, Network Address Translation
(NAT) is being used. NAT provides a very basic level of security. See the Qwest
DSL LAN book for more information about NAT.
Firewalls
The safest way to prevent attacks on the computer is through a firewall – a hard-
ware device or software program that protects the computer from unauthorized
access by controlling who can access your computer and by monitoring the
transmissions between the computer and the Internet
Windows XP has a built-in firewall. For more information, select Help and
Support Center from the Help menu. Search for Internet Connection
Firewall.
If Windows 98, 98 SE, Me, NT 4.0, or 2000, 98, or NT 4.0 is running on the
computer, consider installing a firewall. Hardware and software firewall products
are changing rapidly as more homes and businesses establish high-speed digital
connections between their local area networks and the Internet.