Mailinglist Archive

Introduction to Intrusion Detection Systems (IDS)
>From Tony Bradley, CISSP, MCSE2k, MCSA, A+

One of the most well known and widely used intrusion detection systems
is the open source, freely available Snort. It is available for a number
of platforms and operating systems including both Linux and Windows.
Snort has a large and loyal following and there are many resources
available on the Internet where you can acquire signatures to implement
to detect the latest threats. For other freeware intrusion detection
applications you can visit Free Intrusion Detection Software.

http://netsecurity.about.com/cs/hackertools/a/aa030504_2.htm