sing-box/docs/faq/known-issues.md

DNS

on macOS

auto-route cannot automatically hijack DNS requests sent to the LAN, so it's need to manually set DNS to servers on the public internet.

on Android

auto-route cannot automatically hijack DNS requests when Android's Private DNS enabled or strict_route disabled.

on Linux

auto-route cannot automatically hijack DNS requests with systemd-resolved enabled and strict_route disabled.

System proxy

on Linux

Usually only browsers and GNOME applications accept GNOME proxy settings.

on Android

With the system proxy enabled, some applications will error out (usually from China).