Intrusion detection is not for the faint at heart. But, if you are a network administrator chances are you're under increasing pressure to ensure that mission-critical systems are safe--in fact impenetrable--from malicious code, buffer overflows, stealth port scans, SMB probes, OS fingerprinting attempts, CGI attacks, and other network intruders.Designing a reliable way to detect intruders before they get in is a vital but daunting challenge. Because of this, a plethora of complex, sophisticated, and pricy software solutions are now available. In terms of raw power and features, SNORT, the most commonly used Open Source Intrusion Detection System, (IDS) has begun to eclipse many expensive proprietary IDSes. In terms of documentation or ease of use, h...