2. [Asus router as client] If the OpenVPN profile enables IPv6, Asus router enables IPv6, and OpenVPN client on Asus router sets DNS to exclusive, the expected behavior should be that all DNS queries will go through the VPN. However, currently DNS will go through both the VPN's IPv4 DNS and client router's IPv6 DNS. Usually client router's IPv6 DNS responds faster and the response is used causing DNS leak. I suspect that the DNS redirection for VPN is only set on IPv4. My temporary solution is setting client router's IPv6 DNS to client router's IPv4 DNS encoded in IPv6 format.