IPBan
IPBan is a trusted, free security software to block hackers
...On Windows, RDP, OpenSSH, VNC, MySQL, SQL Server, Exchange, SmarterMail, and MailEnable are watched. More applications can easily be added via the config file. Highly configurable, many options to determine failed login count threshold, time to ban, etc. Make sure to check out the ipban.config file (formerly named DigitalRuby.IPBan.dll.config, see IPBanCore project) for configuration options, each option is documented with comments. Shared failed logins and bans. All your machines work together to instantly block attackers from your entire network.