flexible Network Intrusion Detection System

 Snort is a libpcap-based packet sniffer/logger which can be used as a
 lightweight network intrusion detection system. It features rules-based
 logging and can perform content searching/matching in addition to
 detecting a variety of other attacks and probes, such as buffer
 overflows, stealth port scans, CGI attacks, SMB probes, and much more.
 Snort has a real-time alerting capability, with alerts being sent to
 syslog, a separate "alert" file, or even to a Windows computer via Samba.
 .
 This package provides the plain-vanilla version of Snort.