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Why You Need A Firewall:
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Your computer is represented on the Internet by a series of numbers known as an IP address. This is formed by taking the server address (In GWI's case, 207.5) and the user's assigned address (this can be anywhere from 0 to 255 in both of the last two number segments). For example, your computer would be assigned an address something along the lines of 207.5.144.13, the first two sections representing the server number, the last two identifying your computer.
Once this number is established, the computer divides it into segments that can be used for all different forms of data transfer, harmful or otherwise. These segments are referred to as ports. Each port can be used for one particular task, such as loading a web page or sending a message to a friend. However, many of these addresses are not used for anything, therefore leaving your computer open to various forms of connections that may be used maliciously by hackers.
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How A Firewall Works:
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One way to protect yourself is to use a firewall. What does a firewall do? It blocks off all information from a specific range of ports, leaving "open" the common data ports used for browsing, email and other functions. However, the firewall does continue to monitor these "open" ports.
Some firewall users may notice a slight speed decrease when initially loading a page or checking email. The reduced speed is due to the fact that your computer is now making a connection to the firewall first. The firewall then has to permit the connection, then "hand" your computer the information it requested. The actual connection speed itself doesn't decrease at all, but sometimes the "snappiness" of the connection will. It's a tradeoff, but if you value your security and digital information, don't you think it's worth it?
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Do You Need A Firewall?
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If you spend a lot of time on the Internet, either through a dialup or constant connection via a cable modem, DSL or ISDN, your computer is vulnerable during that time. This is because some of your ports are "open" or available to anyone else who has an Internet connection. The way a firewall knows which connections to accept or reject is due to its programming.
For example, generally web pages are genreally accessed through port 80. The firewall requests these pages and routes them to a different incoming port (port 8080) for security reasons. Your browser would need to be configured for this, but for most other general purpose connections (FTP, email, etc.) the outgoing and incoming ports are the same, requiring little to no extra configuration. If you have a program that requires a connection on a given port, the option to monitor that port while leaving it open is available through the firewall software, thus making a secure connection.
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Some Firewall Choices:
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BlackICE is a very good example of a firewall. It monitors all incoming and outbound connections for intrusions by outside sources, all while running in the background and not interfering with your workspace. Another nice feature is the ability of this program to keep logs of all connections, allowing you to see all of the connection attempts, where they are coming from, and what they are trying to do.
McAfee provides the same protection but with a slightly more user friendly interface. BlackICE leans more toward the small business or telecommuter side of the market. So, if you're a home user and value your privacy, McAfee's Personal Firewall is the way to go. If you like robust port scanning and monitoring, BlackICE is probably a better choice for you.
BlackICE is available on the web through NetworkICE's homepage (http://www.networkice.com). Personal Firewall can be purchased, or you can download the demo, at McAfee's homepage (http://www.mcafee.com).
Published: GWI Newsletter, June 2000.
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