Intrusion Detection & Vulnerability Scanner

OpenVAS is a full-featured vulnerability scanner that includes unauthenticated and authenticated testing, various high-level and low-level internet and industrial protocols, performance tuning for large-scale scans, and a powerful internal programming language to implement any vulnerability test.

Sniffnet is an open-source, cross-platform application to monitor your network traffic. It allows you to set filters to apply to the observed traffic, views overall statistics, set custom notifications, and more.

Snort is an open-source network intrusion detection system and intrusion prevention system that uses a series of rules that help define a malicious network.