In the last three years, the networking revolution has finally come of age. More than ever before, we see that the Internet is changing computing as we know it. The possibilities and opportunities are limitless unfortunately, so too are the risks and chances of malicious intrusions. -In the last three years, the networking revolution has finally come of age. More than ever before, we see that the Internet is changing computing as we know it. The possibilities and opportunities are limitless　unfortunately, so too are the risks and chances of malicious intrusions.