SSHGuard

SSHGuard monitors services through their logging activity. It reacts to messages about dangerous activity by blocking the source address with the local firewall.

Free Open Source Mac OS X Linux

Fail2ban

Fail2ban scans log files (e.g. /var/log/apache/error_log) and bans IPs that show the malicious signs -- too many password failures, seeking for exploits, etc.

Free Open Source Linux

ufw

Ufw stands for Uncomplicated Firewall, and is program for managing a netfilter firewall. It provides a command line interface and aims to be uncomplicated and easy to use.

Free Open Source Linux

Shorewall

The Shoreline Firewall, more commonly known as “Shorewall”, is high-level tool for configuring Netfilter. You describe your firewall/gateway requirements using entries in a set of configuration files.

Free Open Source Linux

Denyhosts

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.

Free Open Source Linux

Firewall Builder

Firewall Builder is Open Source multi-platform firewall management software that supports Linux iptables, FreeBSD ipfilter and ipfw, OpenBSD pf, CIsco PIX and Cisco IOS...

Free Open Source Mac OS X Windows Linux BSD

Advanced Policy Firewall

Server-based firewall. Reacts to attacks with intelligent abilities to detect malicious attempts to enter and reacting by blocking the IP temporarily. Repeated hits will...

Free Open Source Linux

CloudPassage

CloudPassage offers cloud server security and compliance products purpose-built for elastic cloud environments.

Freemium Web

SpyLog

Monitor logs from several sources and execute actions based on some rules. Can be used to protecet against brute-force attacks.

Free Open Source Windows