We'll Leave the Door Open For You!!
by Gary Woods

When your computer accesses the Internet it does so via an IP address. 66.218.71.198 is Yahoo for example. Each computer has an individual IP address with many ports through which data is transferred. HTTP where most data is transferred is port 80, and if you download something using FTP (File Transfer Protocol) it's port 21.

If a program on your computer has asked for data from a particular port it is said to be "listening" on that port. These open ports are where things like Trojan Horses listen for instructions to activate. Unfortunately, any program that listens on a port represents a potential liability. If the program isn't equipped to recognize when too many requests come in it may tie up the entire machine causing what is known as a denial-of-service (DoS) attack.

In general, the fewer the ports on which your computer is listening, the less likely it is to be susceptible to certain types of attacks. One way to see which ports are open on your machine is to use Steve Gibson's ShieldsUP, which you can access at http://grc.com. I also use a program called Port Checker, which is free from PestPatrol http://www.pestpatrol.com.

Thankfully, there are some good ways to protect your self. First, make sure that you're downloading all the critical updates from Microsoft. Second look into a personal firewall program like Norton Internet Security http://www.symantec.com/ or Zone Labs program Zone Alarm Pro http://www.zonelabs.com/.

If you have any suggestions or questions for me please drop me a note at garyandlaury@santabarbaraproperties.com or see my column on the Internet at http://www.santabarbaraproperties.com or call me at (805) 729-0910