I’ve started moving some (very!) old projects to GitHub. This one deserves a mention since it’s still useful:
SSHDShield is a daemon that monitors your sshd log looking for signs of a brute force attack and reacts to them.
When I created this small tool, back in 2005, I needed something to protect SSH servers from brute-force attacks, mostly using iptables to block attackers for a long time. I wrote it in C++ since I needed a tool with the smallest footprint possible, which was way below that of similar tools written in Perl.