My ISP (Vi) is only providing public IP and DNS in IPv6 format and there is no IPv4 public IP or DNS is assigned.

So the 8.8.8.8 or 1.1.1.1 DNS are not working. However there is no provision in Archer MR600 to define DNS in IPv6 format.

I reset my PC WiFi connection and it is now picking up the IPv6 DNS set by ISP. But in Android I have downloaded DNS changer IPv6 app to give the DNS provided by ISP. And it is now working fine. (Posting this so that it will resolve others problems who are searching on internet.)

So my query is. Is there any way by which we can define DNS in lan settings in the IPv6 format in LAN settings as the IPv4 DNS (8.8.8.8 etc) are not working. We can not define IPv6 DNS in each and every device getting connected to the router like TV, Alexa etc..

This was not expected from such high end Router in 3G/4G series.