Tripwire

Tripwire is a host-based intrusion detection system focused on file integrity. System administrators are alerted of a possible compromise or failure if important files are changed. When first executed on a server or workstation, Tripwire scans that file system and collects information about the files installed. This information is stored in a database on the Tripwire server. The client then monitors the system and sends an alert to the system owner if the files change.