Security/Privacy/Authentication
Software
OpenSSL
FreeS/WAN
GPG
Tripwire
PAM
Shadow
nmap
Network UPS tools
Portscan
Sniffit
tcpdump
SASL
Snort
Nessus
GNUTLS
Hardware
APC (UPS)
Publications
Building a Honeypot
Know Your Enemy I
Know Your Enemy II
Know Your Enemy III
O'Reilly Security Alerts