Fail2ban - Intrusion prevention framework
TinyWall - Lightweight and non-intrusive firewall
SSHGuard - SSHGuard monitors services through their logging activity.
SonicWall - SonicWall security solutions protects your network, systems, users and data from cyber threats.
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.
pfSense - pfSense is a free and open source firewall and router that also features unified threat management, load balancing, multi WAN, and more