Inexpensive software and hardware can help avert security disasters. Here's what you need to know to keep your business up and running.

The word MSBlast is enough to strike fear into the heart of any small-business owner. But as is the case with many computer security problems, this recent outbreak could've been easily prevented with good practices and the right software and hardware. Here's what you need to know to keep your business up and running.

Update early and often
The first step doesn't require you to purchase anything. You simply need to make sure that every computer on your network has the latest patches and updates. Both Microsoft Windows XP and Apple Mac OS X make it easy for you by including utilities that automatically scan your system, download any updates, and install them for you. But you must make sure that all of your employees are taking advantage of this; if everyone kept their PCs up-to-date, MSBlast would have been a nonevent.

Second, install a good antivirus program and keep it current. McAfee VirusScan and Symantec's Norton AntiVirus are the two most popular products--and both are fine choices--but many other solid products are on the market as well. Antivirus programs rely on a database of virus definition files to recognize and eradicate viruses. When a new one pops up, nearly all of the antivirus companies automatically update their definition files, which is why it is critical to keep your antivirus program updated regularly. If you have a network with 10 or more PCs, you should consider investing in a network solution with multiple client licenses; these protect servers as well as client PCs and include administrative tools so that you can ensure that all systems keep an antivirus program installed and up-to-date. All it takes is one weak link to break the entire chain.

Build a wall around your PCs
While antivirus programs are critical, they can't handle all types of security threats. There are two basic types of firewalls--hardware and software--and we recommend that you use both. Until recently, hardware firewalls were strictly for large companies, but thanks to the rapid spread of wireless networking, many router/gateways now include hardware firewalls that monitor incoming Internet traffic. In most cases these require no real setup or ongoing maintenance--they just work in the background. For complete protection, you should consider adding a software-based firewall such as Symantec's Norton Personal Firewall, Zone Labs' ZoneAlarm or ZoneAlarm Pro, or McAfee's Personal Firewall Plus. These are suitable for small networks and require nominal configuration to distinguish between legitimate incoming and outgoing traffic and digital trespassers.

If you're really worried about security, also consider a network-intrusion package, which will alert you if someone has made it past your defenses and will give you time to track down who they are. These utilities can be expensive, but they are surprisingly easy to use. You'll also find numerous scanning utilities, which probe your network for holes and vulnerabilities, available for free. Finally, consider investing a few hundred dollars in an independent security consultant who can install some of these applications for you and show you how to use them.

McAfee VirusScan 8.0
VirusScan 8.0 sports a trimmer profile, a simpler interface, and fast performance.

More options
Norton AntiVirus 2004
Sophos AntiVirus 3.7

Firewalls
ZoneAlarm Pro 4.0
A great personal firewall program anyone can use.

More options
BlackIce PC Protection 3.5
McAfee Desktop Firewall 7.5
Symantec Client Security 8.0

Christopher Null is a freelance business and technology journalist in San Francisco. He has written for Wired, Smart Business, PC World, and Business 2.0.  He is also a veteran of numerous small businesses--including his own Internet start-up, filmcritic.com, which he has operated since 1995.