Bobcaygeon Promoter, February 22, 2002
NetScoop: Stop Intruders with a Firewall
by Anne Panter
In my last NetScoop column, I described "spyware", programs which install themselves on your system then send information from your computer to the internet, and suggested a couple of programs (AdAware and Xblock) which can find and remove spyware from your system. These programs won't, however, prevent spyware from spying. For that, you need a firewall.
Like their namesakes, which prevent fires from penetrating from one part of a building to another, firewall programs protect your computer from unauthorized intrusions. A firewall watches the "doors" (ports) in both directions, monitoring when your computer tries to access the internet, or when another computer tries to access yours.
"Spyware" programs aren't the only intruders trying to use your computer. For instance, "Trojan Horse" viruses can slip in disguised as legitimate programs, or hackers, wanting to cover their tracks by working from someone else's IP address, might "break in" to yours. Particularly if you have a broadband (cable or DSN) connection, and even more so if you leave your computer running (often unattended) all the time, you should consider installing a firewall.
One popular firewall program, ZoneAlarm, is available free from www.zonelabs.com. When you install ZoneAlarm, you tell it which programs on your computer are allowed to access the internet. For example you don't want to block your browser, email program, or virus update program. If anything else tries to use your connection you will be asked "Do you want [whatever] to access the internet?" If it's something acceptable, you can answer "yes", and, if you want, add it to the list of accepted programs. But if it's a program you weren't aware of, you can say "no", and check into it further later.
Meanwhile, if another computer tries to access files on yours, you will get a message "The firewall has blocked internet access to your computer from..." . Again, you can allow certain servers access to your files (maybe you are sharing music files?), and lock out any other intruders.
Incidentally, if you are concerned about leaving all the doors open, you should close a gaping security hole left by Microsoft in their Windows operating system. I have copied the following instructions directly from the CanadaComputes web site:
"Open the Control Panel's Network dialogue box, select the first TCP/IP entry, and click on Properties. In the Properties dialogue, select the Bindings tab, then deselect File And Printer Sharing For Microsoft Networks. Repeat this procedure for all TCP/IP entries. Also, deselect Client For Microsoft Networks on all but the first entry. Click OK, then restart your system. "
For more information on this, or any other internet topic, come to the next meeting of the Kawartha Internet Users' Group. We meet on the 2nd Thursday of each month, 7pm, at the Lions' Hall, Main St., Bobcaygeon.
apanter@kawartha.net
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