Fail2ban!

SSHGuard monitors services through their logging activity. It reacts to messages about dangerous activity by blocking the source address with the local firewall. SSHGuard employs a clever parser that can transparently recognize several logging formats at once (syslog, syslog-ng, metalog, multilog, raw messages), and detects attacks for many services out of the box, including SSH, several ftpds, and dovecot. It can operate all the major firewalling systems, and features support for IPv6, whitelisting, suspension, and log message authentication. »

The idea of denying access to SSH servers is nothing new and I was inspired by many other scripts that I discovered. However, none of them did things the way I envisioned them to. Also, they were all shell scripts which do not offer the elegance of Python.

A FREE and open source application that allows banning ip addresses from failed terminal services or SQL server logins out of the box. Other types of banning are easily added via an application configuration file.

Tallow is a fail2ban/lard replacement that uses systemd's native journal API to scan for attempted ssh logins, and issues temporary IP bans for clients that violate certain login patterns.

RdpGuard allows you to protect your Remote Desktop (RDP) from brute-force attacks by blocking attacker's IP address. Fail2Ban for Windows.

HeatShield is a network firewall management service for Linux servers. A firewall configured by HeatShield prevents unauthorized access to services running on your servers, such as SSH and MySQL. Using HeatShield, you can easily restrict access to these services so that only IP addresses you trust are allowed to communicate with your servers.

e.guardo protects your RDP, MSSQL, FTP, SMTP, EXCHANGE, OWA, LYNC, MICROSOFT DYNAMICS CRM, SHAREPOINT and many more services from Brute Force and Dictionary Attacks

Lit Fuse Intrusion Detection (LID) protects your Windows system from brute force attacks and other intrusion attempts by placing a brick wall between your server and would-be hackers. Lightweight and lightning-fast, our software keeps an eye on your network traffic 24/7, watching for suspicious activity.

lua-spylog - Execute actions based on log records

IPQ BDB filtering is done by a user space netfilter daemon that issues verdicts after looking up the IP address in a Berkeley DB. The fuzzy blocking model, freely inspired by STOCKADE, is designed to block non-distributed dictionary attacks and mitigate spam.