Voir aussi Routeur Firewall
http://www.cio.com.au/article/373991/5_open_source_security_projects_watch
http://en.wikipedia.org/wiki/Intrusion_detection_system#Free_Intrusion_Detection_Systems
http://en.wikipedia.org/wiki/Host-based_intrusion_detection_system
http://en.wikipedia.org/wiki/Network_intrusion_detection_system
http://en.wikipedia.org/wiki/Intrusion_detection_system
http://www.linux.com/news/software/applications/797378-10-open-source-security-software-tools
http://www.linuxjournal.com/content/secure-server-deployments-hostile-territory
http://www.unixmen.com/protecting-apache-server-denial-service-dos-attack
http://www.makeuseof.com/tag/5-ways-protect-zero-day-exploit