TCP/IP and Ports
Computers use the TCP/IP protocol when connected to the Internet. In a sense, TCP/IP is the language the computers use to communicate with each other.

A computer using TCP/IP has several thousand ports the computer listens to. You can compare it to the old phone system. You may have seen the old phone setup with human operators connecting wires into boards in order to complete calls. Ports in TCP/IP are very similar to that board.

By default, most or all of those ports are open and waiting for something from the Internet to connect to it. The problem is that most of them aren't used or needed.

In a sense, it's like having all the doors and windows in your home either open or unlocked. It certainly makes it easier for the people you want to come in to get in, but it also makes it easier for people you don't want to get in to get in.

Firewalls
There are programs available that prevent people from accessing ports that are not being used. They are lumped under the general name of "firewall" programs.

Basically, firewall programs close and lock the open windows and doors in the previous analogy. There are several different firewall programs available for the PC and Macintosh.

StarNet cannot recommend any particular program for use. However, it should be noted that the company Zone Labs has a firewall program available for the PC (called ZoneAlarm) that is free for personal use.

You should also be aware of potential problems with firewall software. First, if you lock all the doors in your home, you could potentially lock out your friends or others you want to come in. Similarly, a firewall program could (at least initially) prevent some of your programs from working or cause erratic behavior.

Second, we have seen firewall programs raise the alarms that your computer is being attacked when it is actually just regular network traffic.

Thus, installing a firewall should provide increased protection, but may mean spending some time looking at the documentation of the program to configure it for your needs. It might also require some time to learn what is an malicious attempt to access your computer and what is regular network traffic.