> My ISP does not advertise DNS via RA

What does the rdnssd line in your system log say? It should be either `Get IPv6 address & DNS from DHCPv6` or `Get IPv6 address from RA & get DNS from DHCPv6`. Asus added code that inspects what flags are set on the incoming ICMP6 packets and sets the value of `ipv6_ra_conf` accordingly. The only time that `ipv6_ra_conf` equals `noneset` is when the incoming ICMP6 packets are flagged that DNS is available from RA.