FastFwD is a small daemon that allows users to set up port forwarding from a source IP address and port number to a target IP address and port number easily without the need to deal with complicated ipchains/iptables-rules. FastFwD offers a fault-proof possibility for port forwarding between two networks or IP addresses and additionally gives the possibility to password-protect this connection. FastFwD has been tested for Linux and QNX and should compile and work with all POSIX-based systems.
SpamCheetah is a network-level spam filtering solution built around OpenBSD greylisting, tarpit, and blacklisting. It comes with a Web interface and requires zero administration. It does not allow spam to even land in your network, thus saving you precious bandwidth. It does not have the 'false positives' problem of losing legitimate mail.