Legacy static-IP DNS setup

This setup applies only to the small number of accounts provisioned before we introduced DNS-over-HTTPS. New signups don't use this path — see DoH setup instead.

Set your router's DNS server to our server's public IP address (shown on your dashboard). This only works reliably if your ISP gives you a static — or at least long-lived — public IP address. If your IP changes, update it from your dashboard's instance page so routing keeps working.