fail2ban / fail2ban

Daemon to ban hosts that cause multiple authentication errors

stamparm / maltrail

Malicious traffic detection system

stratosphereips / StratosphereLinuxIPS

Slips, a free software behavioral Python intrusion prevention system (IDS/IPS) that uses machine learning to detect malicious behaviors in the network traffic. Stratosphere Laboratory, AIC, FEL, CVUT in Prague.