C - ConfigServer S - Security & F - Firewall

CSF conducts a Daemon process that checks login authentication failures for:

Courier imap, Dovecot, uw-imap, Kerio |openSSH | Pure-ftpd, vsftpd, Proftpd | Password protected web pages (htpasswd) | Mod_security failures (v1 and v2) |Suhosin failures | Exim SMTP AUTH | Custom login failures with separate log files and regular expression matching

The CSF script suite provides

Straight-forward SPI iptable firewall script | POP3/IMAP login tracking to oversee logins per hour | SSH login notification | SU login notification | Excessive connection blocking | BOGON packet protection | SYN Flood protection | Ping of death protection | Port Scan tracking and blocking