Automatic DNS doesnt work for Wireguard after stopping Adguard Home

Max3 · 2022-06-01T12:31:34.022Z

(Tested on Version: 4.0.0 release2)
I am using Wireguard Client (Proton VPN).
I then started Adguard home using Dns ovet TLS (NextDNS). All is working fine but if I stop Adguard Home, DNS from Wireguard doesn’t work anymore and I can’t surf (DNS is set to Automatic in DNS tab and it’s showing “DNS from Wireguard”).
If I enable DNS over TLS (using stubby), all is working again but if I try to set DNS on Automatic, I can’t resolve any DNS.
Nothing useful on system log…

yuxin.zou · 2022-06-02T02:36:45.704Z

We are trying to reproduce this issue.

Max3:

I then started Adguard home using Dns ovet TLS (NextDNS).

Do you mean you have input “tls://dns.nextdns.io” in AdGuard Home’s “DNS settings” page?
Did you update AdGuard Home version manually?

Max3 · 2022-06-02T04:57:41.770Z

Yeah, I used “tls://dns.nextdns.io” and all was working flawlessly.
The problem arised when I stopped Adguard Home from UI.
Wireguard DNS were not working anymore after that. I can’t surf most websites. For example, I can surf https://forum.gl-inet.com/, I can do a Google search, but most websites won’t open (Chrome is giving me a DNS probe started message).
Also, this is dnsleak result:

Cattura1917×692 37.8 KB

Re-starting Adguard home fix the problem (or manually changing DNS in DNS tab).
Anyway there’s no way tu use Wireguard client again without Adguard Home or without manually changing DNS, I think I have to reset the router and retry from scratch to reproduce the iussue.
Wireguard configuration was working without problem until I started and then stopped Adguard Home.

Max3 · 2022-06-02T07:53:53.815Z

Ok, trying to reproduce the problem, I found the culprit.
This was happening because on WAN interface “Use DNS servers advertised by peer” was UNCHECKED.
Strange thing is that I didnt unchecked it manually… so I really don’t know what happened there…

Max3 · 2022-06-03T14:41:44.974Z

Ok, today this happened to me again when I was testing some Wireguard client servers.
I switched from a couple of servers, then after a little while I stopped Adguard Home, and the problem came back. I couldn’t surf or resolve any DNS. This time “Use DNS servers advertised by peer” was CHECKED.
Again, nothing useful on system log. This happened after I completely reset the firmware and reconfigured the router. Defenitely there’s something wrong…

alzhao · 2022-06-06T06:45:01.773Z

@dxf can you check if this is a bug?

Max3 · 2022-06-12T09:08:59.856Z

Ok, after trying a lot, seems that’s not related to Adguard home.
How to reproduce this DNS problem:
Reset firmware, setup PPPOE connection, check “Override DNS Settings for All Clients”, Start Wireguard Client (Proton VPN), set-up VPN policy (MAC ADDRESS) to exclude at least 1 device from VPN.
Then reboot, DNS resolution doesn’t work everytime for me. To make it work again, I must stop Wireguard client or, if Adguard home is activated, I must stop it (that’s why I thought it was Adguard home related).
But sometimes just switching WG server makes the problem arise again.

alzhao · 2022-06-13T08:04:21.197Z

This seems a very complicated operation. I asked developer to investigate.