Online books
Computer Networks Demystified Computer Networks Demystified is an e-book that explains principles of computer networks
Handbook of Applied Cryptography This Handbook will serve as a valuable reference for the novice as well as for the expert who needs a wider scope of coverage within the area of cryptography.
Firewalls and Internet Security: Repelling the Wily Hacker Firewalls and Internet Security became the bible of Internet security by showing a generation of Internet security experts how to think about threats and solutions
Blogs
Igor Pavlekovic ...it's because of IT...
Marin Frankovic I am legend
Software
Ethereal Ethereal is used for troubleshooting, analysis, protocol development, and education. (See also: Wireshark)
PuTTY PuTTY is a free implementation of Telnet and SSH for Win32 and Unix platforms