What it does
sing-box is a GPL-licensed proxy platform with a documented TUN interface, automatic routing options and destination-based route exclusions.
sing-box can use a TUN interface to direct system traffic through configured outbound connections. Its documentation separates automatic routing, route inclusions and exclusions, with platform-specific behavior. For Linux, the documented auto-redirect option uses nftables and has specific interactions with routing marks and container bridges.
Plan the routing rules and outbound server before enabling the interface. Automatic routing needs an interface-selection setting to avoid looping traffic back into the tunnel, and the DNS behavior depends on the selected options. This is a configuration platform for a network path you supply, with graphical clients documented separately.
Strengths
- Detailed route inclusion and exclusion controls
- Platform-specific TUN and DNS documentation
Watch out for
- Requires deliberate interface, route and outbound configuration
Best for
- Technical users building a controlled proxy-based system route
Sources
- Home - sing-box (Oct 26, 2026)
- Tun - sing-box (Oct 26, 2026)