Ossec - OSSEC is an Open Source Host-based Intrusion Detection System.
Fail2ban - Intrusion prevention framework
Samhain - The Samhain host-based intrusion detection system (HIDS) provides file integrity checking and log...
RdpGuard - RdpGuard allows you to protect your Remote Desktop (RDP), POP3, FTP, SMTP, IMAP, MSSQL, MySQL, VoIP/SIP from brute-force attacks by blocking attacker's IP address. Fail2Ban for Windows.
Tripwire - Open Source Tripwire software is a security and data integrity tool useful for monitoring and...
SSHGuard - SSHGuard monitors services through their logging activity.