With an always-on connection such as DSL or cable, your computers are open to the world on a permanent basis, giving any malicious person the opportunity to attack them. Firewalls, which are also useful for dial-up users, are designed to act as defences against Internet-borne attacks. They keep a watch on all incoming and outgoing data, blocking malicious code or personal information to prevent file damage or loss of privacy.
It sounds simple, but the implementation is complicated, not least because all Internet data is sent as packets. A good firewall must read enough of these packets in one go to recognise any malicious code.
As a first line of defence, there are several software firewall applications available. One such tool is Symantec’s Norton Personal Firewall. This does the usual firewall trick of preventing access to your PC’s open ports by external hosts – with the option of hiding the ports completely – and it can keep a log of these intrusions (expect about half a dozen alerts for every hour online).
As well as port blocking and cookie filtering, this piece of software will prevent confidential information – as defined by the user – being transmitted over the Web or via instant messaging systems such as AIM and Windows Messenger.
Norton Personal Firewall analyses Internet-aware applications and checks for suspicious activity, comparing them with a database of ‘legitimate’ applications and producing a warning message if anything suspicious occurs. Rules can be configured on a per-site basis, so you can allow downloads from trusted sites and reject them from unknown sites. This, of course, means quite a lot of user interaction.
Although pitched as a suitable product for home users, a certain level of technical knowledge will be required – not to install the product but to understand the various configuration options. Even though there’s a walk-through wizard, some of the terminology will confuse less technically-savvy users.
Norton Personal Firewall includes a year of free updates – to cope with new varieties of malicious code – in the purchase price, following the business model set by the anti-virus software manufacturers.
Contact: 020 7616 5600