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.
TIPP is an IP planning application for network departments of organizations with medium- to large-sized networks. While providing all the necessary functions for keeping track of your IP and network allocations, it combines simplicity of design and use with a clean and thoroughly modern look and feel.