tgcd is a simple Unix network utility to extend the accessibility of TCP/IP based network services beyond firewalls. This can also be used by network analysts and security experts for penetration testing and analyze the security of their network.
It's written in C Language.
Bruteblock allows system administrators to block various bruteforce attacks on UNIX services. The program analyzes system logs and adds attacker's IP into IPFW table effectively blocking them. Addresses are removed from the table after expiration period