Put up the barriers

Is the Windows Firewall enough?
If Windows comes with a firewall, why do products such as Zone Alarm’s firewall exist? Originally, the Windows Firewall was designed only to keep undesirables out, and it did nothing to prevent your PC sending out data without your knowledge.

However third-party firewalls exist, both free and paid-for, some of which take the concept much further. Many of them are paid for on a subscription basis, so they can include regular updates, in much the same way as anti-virus or anti-spyware software is maintained. They can also include many more sophisticated security techniques.

Many forms of malware reside on your PC and either hijack it for use in distributed attacks or divulge your personal information, potentially even banking details, by secretly snooping on you and sending your details to a third party. Anti-virus and anti-spyware software should root out these offenders, but only a sophisticated firewall can effectively block them once they are running.

Software versus hardware
A firewall application, like any software running on your PC, is going to consume CPU power and system memory, effectively slowing down your PC. Hardware firewalls are commonplace in corporate networks, but you’ll also often find them in the home usually as part of an ADSL or cable broadband router. Although this is technically firmware rather than hardware, the essential point is that it’s not running on your PC. This means it won’t slow your PC down while it works.

However, this also means it can’t block applications on your PC from sending data on your network (although it can use clever techniques, known as stateful packet inspection, or SPI, to try and ensure only legitimate connections are allowed). You’ll also find yourself unprotected if you move your PC to another network, as is often the case with notebooks.

Yoggie Security Systems makes hardware-based firewalls that can be installed in a laptop or PC via a USB or Express Card interface. These offer the performance advantages of a hardware firewall by offloading work from your CPU, and allow for protection of an individual PC whether it’s connected to your home network or a public Wifi hotspot. Read our review here.

Hardware firewalls can also be more robust against certain attacks as they can deal with threats before they get to your PC’s memory.

If you’re interested in boosting your system’s security and taking a close look at what’s going on in your network, we would recommend taking a look at a third-party firewall such as the free version of Comodo Firewall Pro, Outpost Firewall Free 2009, PC Tools’ Firewall Plus, Webroot Desktop Firewall or Zone Alarm.

All these products offer enhanced security as well as additional features and a simple user interface. These are all good for giving you basic protection, and some offer upgrade routes to more advanced paid-for versions.

Security suites
A software firewall often comes as part of an internet security suite. These offer the advantage of an integrated package that allows anti-virus, anti-spyware and firewall options to be configured from a single interface. If you do use a third-party firewall, make sure you turn off the Windows Firewall, as it’s not a good idea to run two software firewalls at the same time.

This article was first published in June 2009.