DenyThem is a program designed to protect your Linux system from malicious attacks. It is an active response system to disrupt and block dictionary attacks and DOS attacks. DenyThem by default uses /var/log/syslog and /var/log/auth.log and searches for hack attempts. When DenyThem finds enough hack attempts from a single host, it will add a DROP statement to your system's firewall, thus preventing future attacks. DenyThem uses iptables, so it will only work on Linux or any other system that uses iptables. It can also block traffic from specific countries.
