Snort's homepage
http://www.snort.org
SecurityFocus IDS Page
http://www.securityfocus.com/ids
The SANS Institute
http://www.sans.org
CERT homepage
http://www.cert.org
The NSA Security Guides
http://www.nsa.gov/snac/index.cfm
tcpdump homepage
http://www.tcpdump.org
ethereal homepage
http://www.ethereal.com
