by Jeff Smith
Think of a firewall as a kind of force field between your computer and the internet. It can block information from coming or going. It can keep out data thieves and it can keep spyware from making reports on you. Unfortunately, unless it is configured right, it can also block good programs from accessing the net.
First understand that all net traffic to your computer travels to specific ports. To understand what a port is, imagine for a moment that your computer is a large apartment building. And that all your programs are the tenants. Ports are like the large group of mail slots in the lobby. In this analogy the internet is the mailman and the mail is the packets of information that make up your emails, web pages, instant messages etc. Just about every net program uses a port. Of course this all happens much faster than the US Postal Service. You must also understand that your internet connection only has one set of ports ranging from 0 to 65535.
A firewall controls whether these ports are open or closed. Without a firewall all of these ports are open and vulnerable. Using open ports, hackers can take control of your machine by exploiting security flaws in Windows itself or other internet enabled programs.
Firewalls can be either software or hardware based. The most popular software firewall is a program called ZoneAlarm. Its popularity is due to its ease of use and because they have a basic version that is free for personal use. You don't have to know anything about ports to use ZoneAlarm. Programs will ask permission before accessing the net, and you can allow net access to trusted programs or deny the ones you are not sure about. Its talkative at first, but it quiets down after it learns your preferences. Just like antivirus, you should only have one software-based firewall on your system at one time. Windows XP has a built-in firewall but I personally find it to be inferior because it is somewhat lacking in configuration options. So if you're going to get a software firewall, be sure to turn off the Windows firewall. Another good and free software firewall is Comodo Free Firewall. I have not used it personally, but it has gotten very good reviews. Either of these can be found at www.DOWNLOAD.com. Software firewalls can often help you spot spyware infections because you'll see them asking for access to the net.
A hardware firewall just another name for a router. A router basically splits out your broadband connection to multiple computers or broadband-ready devices such as one of the newer game consoles. Using a router to connect two or more computers is called networking. Because your connection only has one set of ports, the router must decide which PC gets to use which ports. This can sometimes be problematic if two or more PCs need to use the same ports but we'll save that subject for a later date. Assigning an outside port to a computer on your network is called port forwarding, or port tunneling. Ports that are not assigned to a PC are essentially closed to the outside world and therefor safe from outside attack. Common routers will usually accommodate four computers and prices start at around $20 and go much higher depending on features. If you have a router and need help configuring it try going to www.PORTFORWARD.com and look for help with your particular model.
Using a firewall is a basic and essential part of any computer security setup.
That's it for this week, next week we'll be discussing PCs vs. Game Consoles. Until then good luck and safe computing.