Opensnitch is a host-based application firewall for Linux that monitors and intercepts outbound network connections in real time. By hooking into kernel-level interfaces, it tracks system-wide network activity and maps connection attempts to specific local processes, allowing users to explicitly permit or deny traffic on a per-application basis.
The project distinguishes itself through its ability to manage security policies across multiple distributed nodes from a single, unified dashboard. This centralized management is secured via encrypted socket communication, enabling consistent rule enforcement and monitoring across remote machines. It further supports granular control by validating executable integrity, filtering based on environment variables, and isolating process network access to prevent unauthorized data transmission.
Beyond basic filtering, the system provides comprehensive observability tools, including real-time connection inspection, traffic logging, and the ability to export security events to external management systems. Users can define complex, prioritized rule sets that incorporate blocklists, temporary access durations, and path-based restrictions to secure their environment against unauthorized communication.
