[Solved] Custom DNS Screwed up on Version 7.7

[Prince_of_Nigeria]

I'd been using DNS-over-TLS with a custom NextDNS address (https://nextdns.io/) happily and successfully before version 7.7. Then, yesterday, I upgraded to version 7.7, and decided to try out DNS-over-QUIC, since it was one the new features.

Navigating to Settings -> DNS Protection and scrolling down to "Custom DNS Servers," I switched my NextDNS custom server from tls:// to quic://. Well, after browsing for a few hours, I experience slowness and disconnects (a lot of HTTP 404 requests). So I decided to switch back to tls://, like I'd been using for many months. All I had to do was to edit quic:// back to tls:// It should be no problem, right? Wrong:




Can someone please explain to me how tls:// is somehow now an invalid address, when the only thing that changed was the protocol? I didn't change the address, only the protocol! Now, somehow it's not accepted! But when I use the same address, but with quic://, it's accepted! Is this a bug?

 

[a.shulgin]

Hi

Most likely, the address you added is no longer valid. Can you write us which address you want to add so that we can check it?

 

[Prince_of_Nigeria]

Thank you for your reply. I've sent you a message with the information you requested. Though, I don't think that the address is invalid, since I can use it with quic:// just fine, but only with tls:// it registers as "invalid." But even so, with AdGuard versions before 7.7, it was working perfectly as tls://. So I strongly doubt that it's an invalid address.

EDIT: Also, AdGuard for Android -- which I've been using for years as well -- doesn't have this problem. I can still use tls:// with the NextDNS address. So I'm almost certain that this is a bug with Android 7.7 for Windows.

 

[Prince_of_Nigeria]

When I try to switch custom DNS providers, I have even more problems. AdGuard kills my Internet connection; I can't connect to any websites, and instead get HTTP 404 errors. This happened when I tried to switch to Quad9, and it happened twice. In both times, the AdGuard service itself actually froze; I couldn't pause protection, and ultimately the notification area icon turned yellow with an exclamation mark, and I received a message that there was a problem starting the service. I had to restart my computer to restore my Internet connection.

Even after restarting, my custom DNS settings -- Quad9 over TLS -- didn't take effect right away. I tested the DNS by following the instructions on this webpage, and the test failed. I had to restart the program completely in order to get DNS filtering working. So there seems to be some problem with DNS filtering, at least on my computer.

EDIT: After some more testing, it seems that custom DNS with HTTPS works fine, as does DNSCrypt. If I switch to AdGuard DoH or AdGuard DNSCrypt, then the AdGuard DNS homepage can correctly detect that I'm using AdGuard DNS. Same thing with NextDNS; if I use DoH with a custom NextDNS address, then it works fine, and the AdGuard program will accept the custom URL. But again, for some reason, the program doesn't accept the tls:// version of the same URL.

 

[adnd]

It's not solved at all...https://github.com/AdguardTeam/AdguardForiOS/issues/1815