AdGuard is using incorrect DNS servers

Routers VPN, DNS, Leaks
1

So I recently bought Flint 2 and I’m trying to configure AdGuard with encrypted DNS queries (like DoH or DoT). But I have a problem where statistics show that most (around 72%) of DNS queries go to the WAN provided IP addresses, and as far as I understand is completely unencrypted in plain text. I’m not sure if I’m doing something wrong or maybe it is completely normal and I shouldn’t worry about it?

So roughly I followed steps from this comment: https://www.reddit.com/r/GlInet/comments/198jv9m/adguard_home_setup_on_glinet_6000_flint2_router/

  1. Browse to Settings>DNS Settings
  2. Configure Upstream DNS servers. This is what I'm using (feel free to change)
    quic://dns.nextdns.io:853
    https://dns.nextdns.io:443
    quic://p0.freedns.controld.com:853
    quic://p0.freedns.controld.com:853
    https://dns.cloudflare.com:443/dns-query
  3. Make sure you're not using IP addresses (e.g. 1.1.1.1) otherwise, your DNS queries aren't encrypted
  4. Use parallel request
  5. Bootstrap DNS leave default
  6. Enable EDNS client subnet and DNSSEC
  7. Enable Optimistic caching

I’m not entierely sure what they meant by couple of first steps so I didn’t do anything about them (I have hardware acceleration enabled, or I didn’t touch DNS server on my router).

And now in AdGuard statistic I see:

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So the first two addresses are the default DNS provided from the WAN connection.

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I don’t quite get it why it is the case. I’m unable to change this DNS unless I swap the config from using DHCP server from my ISP to a static IP. I’m not sure if I should do it?

I have Connect Box CH7465LG provided by UPC (my internet provider) in modem mode and then I have Flint 2 connected to it via Ethernet cable.

2

Are you sure that all devices use your AdGuard server?

Enable Override DNS Settings of All Client within the GL UI Network Settings>DNS

3

I’m not 100% sure, but I think they are.
I have this options enabled.

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4

I think I’ve found the issue. It might be connected with the Private reverse DNS resolvers. By default the list of reverse DNS servers is empty, and I believe the checkbox to use this feature is also enabled by default. And since the list is empty it will use the IPS provided DNS servers, and will try to ask about my local IPs all the time, therefore creating huge artificial traffic in the statistics.

I put there IP address of the router itself and I will monitor if the top upstream DNS servers will change after some time. Thanks

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