Linked by Thom Holwerda on Fri 7th Jul 2006 13:11 UTC, submitted by anonymous
"The first time I have seen the knockd project I liked it instantly. The idea is so simple, and though so effective. Knockd is a port-knocking application that silently runs on a server passively listening to network traffic. Once it will see a port sequence it has an action configured for it, it will run that action. We can see this as a remote control to our server: once we hit the right button it will take the appropriate action!"