WiFi stops working with private DNS via dns.adguard-dns.com

bers

New Member
Hi,
I observe some strange behavior with a Huawei P30 on a company (Guest) WiFi with a captive portal (that does not usually appear, just only once in a year or so).

Essentially, I can connect to the WiFi without private DNS, and I can connect to the WiFi with private DNS via unfiltered.adguard-dns.com. However, as soon as I switch private DNS to dns.adguard-dns.com, WiFi stops working. What I mean by that is that WiFi stays connected apparently, but Android switches to mobile data nonetheless (I can see the letters LTE appearing over the mobile signal indicator, and speed tests/IP addresses reveal I am using mobile data). As soon as I disable private DNS, WiFi works again. This is happening on this one WiFi only.

I am not sure this is related, but I have noticed that Huawei seems to be using https://connectivitycheck.platform.hicloud.com/generate_204 (followed by something more) rather than https://www.gstatic.com/generate_204, but I do not think this is an issue as I can resolve both correctly via dns.adguard-dns.com.

Any idea what might be causing this issue?
 

H3lper

Member
Staff member
Hello!

Thank you for bringing this up to us.

Based on your information, we imply that this might be an issue with DNS that blocks some connections.
Hence, we'd like you to access your AdGuard Private DNS dashboard at http://adguard-dns.io/. Hit the "Try AdGuard DNS" button and access your account.

Once done, access your query log and reproduce the issue while your Private DNS is working. There, in the Query log you can see and manage all requests during your session and block\unblock those that are relevant and might affect your network connection.

Before you start, prepare your phone and close all your irrelevant apps for your convenience. Then unblock those blocked requests (marked as red in color) and check if the issue persists.

Please let us know your results. Don't hesitate to ask us about anything.
 

bers

New Member
Thanks for the suggestion! I had actually been thinking whether my work WiFi would be blocking DNS requests to AdGuard (which would be hard for your to investigate), but you are completely right - maybe they are relying on a host name that AdGuard is blocking. I would find it very odd if that lead to WiFi disconnects immediately after changing the private DNS, even long after I have passed the captive portal - but it is something I will try. I'll keep you posted.

(Edit: if they *are* blocking dns.aguard.com but not unfiltered.adguard-dns.com, it is also probably they are not blocking my custom 12345.x.adguard.com, in which case my problem would be solved right away.)
 

bers

New Member
Yesterday I successfully logged into the WiFi while using my 12345.x.adguard.com, and then stayed connected after switching to dns.adguard.com - maybe an issue that got resolved on their side in the meantime.
 
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