ZoneAlarm has built a reputation as one of the best software firewalls available, partly because it has since 1999 offered a simple firewall that's free personal use.

The ZoneAlarm Internet Security Suite builds on the firewall to add anti-virus and anti-spyware tools, protection spam and phishing, online privacy (which claims to make the user ‘invisible’ on the internet), identity protection, instant messaging security and parental control.

They’re all administered from a businesslike main interface, which offers very similar controls for each of the suite’s functions. It uses either buttons – for straight on/off settings – or sliders, for things like protection levels. The controls are consistent and obvious in their use.

Unlike other security suites, where the core application is the virus scanner, ZoneAlarm concentrates on the firewall, so much so that the product actually includes two of them. As well as the network firewall, which automatically configures itself so it offers different protection levels for your local network and for the Internet, there's what manufacturer Check Point refers to as an OS (Operating System) firewall.

The idea of an OS firewall is that it monitors the software working on a PC, looking for suspicious actions which might indicate that there’s a malicious program trying to subvert the system. The OS firewall can stop an application running and prevent it from restarting if it detects such a problem.

When it comes to the anti-virus element, ZoneAlarm uses a scanner made by anti-virus lab Kaspersky, generally regarded as one of the most thorough available, and it combines this with hourly updates. The company argues that this frequency is needed because of the rapid movement of modern viruses, which do much of their damage during the time it takes labs to produce the cures and send them to their users. Check Point maintains that it can get initial protection out to customers of ZoneAlarm within about 20 minutes.

There was no major outbreak during the time we were testing ZoneAlarm ISS 7.1, so we have to take their word on this, but we also have to take the word of some customers who have been using the product and talking about it on internet forums, who complain of installation problems and conflicts on some machines, although we saw none during our tests.

Spyware is handled at three different levels. In addition to the aforementioned OS firewall and the main firewall, known bad sites are also blocked, so you're prevented from visiting them inadvertently.

ZoneAlarm may perhaps be accused of taking slightly longer to ‘bed in’ than some Internet security suites and you may see a few pop-up warnings, but it's very soon acclimatises to the way you use your PC and provides fast and unobtrusive protection.

It's disappointing it doesn't include extras such as a file shredder for securely erasing documents, but the price is fair, especially as a three-user license (for those with home networks) costs only £8 more.

Vista compatible: Yes