Troubleshooting DNS Timeouts on a Bypass Router: sing-box Upstream Queries Leave Through the Wrong Network Interface
On an Armbian machine used as a bypass router, both sing-box and WireGuard are running side by side. The router itself resolves internal domain names fine, yet downstream clients that point at it as their DNS server time out every time. The root cause turned out not to be the DNS matching rules, but rather that the traffic sing-box sends to its upstream DNS was choosing the wrong egress interface. ...