FunBike31I do have a local DNS server (pihole) and other devices are connected to it, except for this phone. The problem is when I set the 192.168.0.102 as the only DNS address, it will automatically append the 188.8.131.52 as the 2nd DNS. So it just bypass my own 192.168.0.102 and use 184.108.40.206. I can't find any settings related to this. I think it is just a weird bugs for this firmware.
Do you have a DNS server on your private network?, is it under windows server 2016 or Linux?, what does nslookup answer you - 192.168.0.102? , if you have a DNS server at home, logically you must have PCs, no problem with them and your local DNS?
FunBike31My other devices do include android. I have a OnePlus 6 and it just works. I basically duplicate the wifi settings and it just doesn't work the same in this Asus phone.
When you say other devices, there is no Android I imagine because I think that if you test another Android it will be the same problem.
This is not specific to ASUS but to Android/Google where there is hard dsn coding.
You can try several things, disable IPv6 on your ISP router because I think it continues to try the dns of the router
If you have a terminal/console application for android you can run and see if the addresses are IPv4 or 6
You can also try to put in the 2 static DNS entries the same, i.e. 192.168.0.102 in dns1 and 2
also check that if you use DHCP there is only the Pi-Hole one and if it is static that there is no more DHCP server (router, Box, etc....)
4 or 5 years ago there was a specific topic at Pi-Hole, the title was something like "Pi-Hole works everywhere except Android"
For me it's not a firmware bug, just that Google thinks it's unavoidable and will look for 220.127.116.11