Hackers make headlines when they hit big companies. What doesn't make the papers is the pain and aggravation they cause small ones. New tools arrive regularly to keep your system safe. As an experiment, I loaded Kaspersky Anti-Hacker Personal Firewall on an extra PC and tried to get hacked.Each night I connected the PC directly to my cable modem, making it visible to the Internet. Next, I downloaded the peer-to-peer media-sharing client KaZaa Media Desktop, regularly castigated as a breeding ground for viruses and hacker attacks. I even downloaded a couple of songs as bait.Each day I reconnected my home office network to the cable modem and turned on the intrusion detection software in the Buffalo AirStation WBR-G54 router (tested and reviewed two weeks ago). I then checked the router's log files to see if anyone had tried attacking my network.\u00a0Seems you can never find a hacker when you need one. After a week of hanging out my "come get me" sign, the Kaspersky Anti-Hacker software didn't record any attack worthy of its log files. During the day, the Buffalo log files showed no intrusion attempts, either.Although I didn't get any full-fledged hacker notifications, a disturbing number of information messages appeared via Kaspersky discussing various software (mostly KaZaa and other attached programs) making links here there to other Web sites and applications I didn't know. KaZaa also changed Windows2000 Registry values causing problems recognizing local workgroup machines using Windows networking.Kaspersky and Buffalo protect your network different ways. Anti-Hacker assumes your PC is visible on the Internet, while Buffalo uses network address translation to keep your PC invisible. Kaspersky automatically starts in 'attack detector' mode, ready by default to stop common hacker tricks like scanning the ports (software access addresses) of your IP address. Anti-Hacker offers a range of options for security levels, from allowing everything to only what you specify.The Buffalo router sits between the cable modem and the internal network. Each system on the inside of the Buffalo router gets an IP address in the range of 10.0.1.1-254, which by Internet standards rules can not be routed across the public Internet, making internal system invisible to hackers. When an internal system sends a request out to the Web, the router changes the IP address to a public address taken from the cable modem, and attaches a particular port number to the outgoing packets. When packet responses arrive, the router uses the port number to send the packets to the correct computer. The Buffalo router, like the Kaspersky software, automatically denied access to common hacker port scanning and information queries.Kaspersky Anti-Hacker software costs $39, while the Buffalo AirStation costs around $130, although that includes wireless support you may not need. But you will need something, and your choices are broadening and dropping in price.