I have a PiHole working very well with over 30 clients, but I have one Amazon Fire Tablet which connects to my wifi, gets it’s reserved IP address, but every time gives the error "Private DNS server cannot be accessed"
Can I somehow set this device to use a public DNS IP, or is there something I have missed on the PiHole configuration ? I saw one post about the problem potentially involving DNS over TLS, and if so, what do I need to change on my PiHole setup to facilitate this ?
As an Android device, your Kindle Fire Tablet should already use the DNS server as provided by your router.
'Private DNS' means that your Fire Tablet or probably just its browser tries to use DNS-over-TLS (DoT) or DNS-over-HTTPS (DoH) instead of plain DNS (Do53), either of which would by-pass Pi-hole.
You should verify that neither your tablet's OS nor its browser uses DoT or DoH.
On vanilla Android OSs, you would check that Private DNS is switched to Automatic (or Off). Typing DNS in the system settings search box will bring that up - it's usually located under Settings | Network and Internet.
And browsers commonly expose a Private DNS or Secure DNS option under their privacy and security settings. To use Pi-hole for DNS, that option should be disabled.
I have never used Pi-Hole FTLDNS as my DHCP Server but since it’s based on DNSmasqd I am 100% sure you can do it by using a custom config file with a little bit of help from the man page : https://linux.die.net/man/8/dnsmasq
