throughline

Throughline is a Linux utility that provides visibility into network activity and control over traffic routing. Built in Rust, it emphasizes auditability and security. The tool has two main interfaces: a visualization screen and a policy editor. The visualization screen displays a real-time map of network connections on the host, attributing each connection to the specific process, service, or container that opened it. The policy editor is a drag-and-drop interface that allows users to change where traffic goes by defining routing policies. Users can drag a program into categories such as "Straight out," "Through the VPN," or "Through Tor." No changes are applied automatically; users must explicitly confirm the action, triggering a countdown timer that reverts changes if not confirmed within a set period. Throughline relies on system files like `/proc` and `/etc/services` to determine process ownership and connection directions. It includes safety checks to prevent lockouts or routing errors and runs locally on the loopback interface only.