NAIS is an intrusion detection system based on the idea of providing computer networks with
the technological equivalent of an innate immune system. NAIS works on machines on which
either a web server or a ftp server has been installed. Though still at a preliminary stage,
NAIS provides a completely reliable discrimination between normal and abnormal processes.
It is able to detect and protect servers against new and unknown attacks, and is quite effective
in denying foreign processes access to the server.