Kerio Personal Firewall 4

Kerio and Tiny Personal Firewall share a common heritage, yet have become quite different beasts over the course of the past couple of years, and it's Kerio that now feels a much more rounded and mature product. Like BlackICE, it combines intrusion-detection techniques with traditional firewall filtering, adds application integrity monitoring to prevent Trojans or other malware-modifying application components, and throws in token privacy protection by way of cookie control and banner ad/pop-up prevention.

In self-learning mode, it will ask for temporary or permanent permission for any given new network activity, local or Internet based, and like ZoneAlarm will let the user define secure 'zones' for trusted IP address ranges. Installation is a painless affair and right from the go, in default configuration, Kerio sailed through our barrage of tests.

However, for the more advanced user, Kerio offers a comprehensive set of options by way of a business-like, yet easy-to-operate interface that combines the power of BlackICE with the ease of NetBarrier in a perfect marriage. It soon becomes obvious there's something for everyone here: comprehensive rule sets can quickly be compiled by the technically minded, while the less experienced user isn't left without a hand to hold and so never feels out of their depth.

A lot of thought has gone into every aspect of Kerio. For example, the traffic-history logging offers customisable levels of granularity and can be sent to a remote server for review if necessary. At the other end of the scale, the home user can input credit card details, telephone numbers and other valuable items of personal data and let the privacy protection feature stop any attempts to send the specified information across the Internet.

A free version for home use is available that lacks the content filtering and privacy features, plus much of the more advanced network administration functionality, yet retains all the core security components that a single user would require. The small business user doesn't have to stretch the budget too far either, and this value-for-money aspect coupled with the fact that it really is as stable a firewall as we've come across - the infrequent product updates are testament to that - make Kerio a firewall worthy of careful consideration.