Christopher Gerg, " Managing Security with Snort and IDS Tools" (Repost)

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.