Network Security consists of the policies and activities which govern usability, reliability, integrity, and safety of a network its data.

• http://en.wikipedia.org/wiki/OSI_model
• http://technet.microsoft.com/en-us/library/cc959354.aspx
• http://en.wikipedia.org/wiki/Man-in-the-middle_attack
  • http://en.wikipedia.org/wiki/ARP_spoofing
  • http://en.wikipedia.org/wiki/Evil_twin_(wireless_networks)
• http://en.wikipedia.org/wiki/Denial-of-service_attack
• http://en.wikipedia.org/wiki/Secure_Socket_Layer#Security
• http://www.aircrack-ng.org/doku.php

• http://nmap.org/book/toc.html
• http://netcat.sourceforge.net/
• http://www.wireshark.org/
• http://www.netfilter.org/projects/iptables/index.html
• http://www.offensive-security.com/metasploit-unleashed/Main_Page
• http://www.kali.org/
• http://www.backtrack-linux.org/