DoH bug.

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vahidx4r4x
Posts: 4
Joined: Wed Oct 06, 2021 8:36 am

DoH bug.

Post by vahidx4r4x »

Hi.
Thanks for your great app.
There is a bug that I found couple of days ago.
When I set the DoH on a server, app will automatically push 8.8.8.8 as DNS server intead of custom DoH query, the DNS leak websites shows Google public DNS or the VPN's default pushed DNS.
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admin
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Re: DoH bug.

Post by admin »

Hello,
thanks for the bug report.
However, this behavior is by design.
The DNS 8.8.8.8 and route 8.8.8.8/32 are added to make sure DNS requests are sent over the VPN.
The DNS 8.8.8.8 and pushed DNS are only used to resolve the host name in the DoH URL, all other DNS requests are captured and sent to the DoH URL.
Maybe the DNS leak websites show the DNS requests used to resolve the host name in the DoH URL (In your case doh-sg.blahdns.com)
vahidx4r4x
Posts: 4
Joined: Wed Oct 06, 2021 8:36 am

Re: DoH bug.

Post by vahidx4r4x »

Before the update DNS leak test websites were showing the blahdns servers and DNS queries were blocking the ads. But now all the applications are showing the ads, because of the pushed Google public DNS.
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vahidx4r4x
Posts: 4
Joined: Wed Oct 06, 2021 8:36 am

Re: DoH bug.

Post by vahidx4r4x »

Another example with my own VPN server.
My VPN server's default DNS is 108.61.10.10 wich is for the Constant Company
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admin
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Re: DoH bug.

Post by admin »

I just finished giving the tests and on my side everything works fine. The DNS requests are sent only to the DoH URL.
Try changing the VPN profile and entering a wrong DoH URL. If everything works fine, you may no longer be able to resolve any host name and the VPN log should shown the DoH errors...
vahidx4r4x
Posts: 4
Joined: Wed Oct 06, 2021 8:36 am

Re: DoH bug.

Post by vahidx4r4x »

The problem is because of OpenVpn v.2.5.3. It will work just with v.2.4.9.
Can you make it optional to push 8.8.8.8 in routes?
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admin
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Re: DoH bug.

Post by admin »

On my side it works also with OpenVPN 2.5.3.
Anyway the problem is not related to the 8.8.8.8 route.
Maybe you are using a browser with secure DNS feature like Chrome or this option is enabled in Android settings.
On Chrome this option is enabled by default.
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