Tech Features

Figuring out firewalls

Nov 20, 2007, 13:46 GMT

Washington - If you use a computer, you've heard of firewalls. After all, there's a firewall delivered in recent versions of Windows, and you may also have one in your high-speed modem.

There are even free firewalls online, as well as ones that you can buy. Despite their ubiquity, however, a lot of folks are confused about what firewalls are and what they actually do.

Read on to find out:

Q: I hear the term 'firewall' used all the time. What is a firewall, and why do I need one?

A: A firewall is a software program that monitors all incoming and outgoing activity over a network such as the Internet. Whenever a program such as an e-mail client or a web browser tries to access the internet, a firewall will alert you, asking whether the activity is to be allowed or blocked. If you unblock an activity, you can generally choose whether to unblock it just once or always. If you choose always, then the next time that type of activity is detected, you will not be notified.

A firewall is important because, although most types of access to the internet are initiated by you and are therefore legitimate, some of the most malicious programs around will attempt to steal your personal information and transmit it stealthily over the internet or deposit harmful code on your PC. Without a firewall, you may never even be aware that such activity is occurring. Thus a firewall exists for your protection.

Q: If I use a firewall, do I also need an antivirus program?

A: Firewalls do not take it upon themselves to identify and eradicate particular types of threats. Instead, their primary function is that of monitoring and logging - and alerting you to unsanctioned network activity.

That's why a good security toolkit typically includes a firewall as well as antivirus, antispam, and malware detection and removal tools.

You can use a firewall to view reports of any program that has tried to access your computer or exchange data with it. As you are browsing the list of accesses or attempted accesses, you can generally decide whether to block future activity from a given program.

Be careful at this stage: while you'll recognise some programs and want to continue allowing them access to your computer, others you may not recognise. Before you block access, it makes sense to perform an internet search on the program in question. You'll want to make sure that you're not blocking access from a program that you may need.

Q: Windows XP comes with a firewall, and so does my antivirus program. Which firewall should I use?

A: You'll probably want to use the one that comes with your antivirus program, for two reasons. First, Windows XP's firewall, while offering basic firewall protections, does not monitor outgoing connections. So if you happen to get a malicious program on your computer that wants to send information out without your knowledge, XP's firewall won't tell you about it.

Many third-party firewall solutions offer more thorough solutions. Initially, they're often more annoying, as well, however, since they may interrupt your work with messages asking whether you wish to block a particular type of internet access. Over time, though, the firewalls will have a record of the types of activity you allow and expect, and will prompt you less often.

Second, the firewalls that come with antivirus solutions are designed to work integrally with those antivirus components, so there's little likelihood that you'll run into one part of your security solution raising false alarms about activity initiated by another.

--- Have a computer question? Send it to the Computer Helper at jayd@csi.com.