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DoH (DNS over HTTPS) failure blocks entire internet connection (No Fallback)

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DoH (DNS over HTTPS) failure blocks entire internet connection (No Fallback)

DoH (DNS over HTTPS) failure blocks entire internet connection (No Fallback)
DoH (DNS over HTTPS) failure blocks entire internet connection (No Fallback)
Thursday
Tags: #Network Connectivity #DoH/DoT
Model: Archer C64  
Hardware Version: V1
Firmware Version: Firmware Version: 1.15.0 Build 250729 Rel.63489n(5553)

Hello TP-Link Community,

I am experiencing a critical network reliability issue with my Archer C64 V1 router running the latest firmware.

 

The Issue:

When DNS over HTTPS (DoH) is enabled and the designated DoH server fails to resolve or experiences a connection timeout/error, the entire internet connection drops for all connected devices. It appears there is no proper fallback mechanism implemented in the firmware to default back to standard UDP/TCP DNS (or fallback to secondary standard DNS servers) when DoH fails.

As a result, a simple DNS-over-HTTPS hiccup completely takes the local network offline, requiring a manual router reboot or disabling DoH entirely to restore connectivity.


Expected Behavior:

If a DoH server query fails or times out, the router should automatically fallback to standard DNS resolution (or secondary fallback servers) instead of completely severing internet access for the network.

 

Thank you for your time and support!

File:
Screenshot 2026-08-06 at 13-28-53 Archer C64.pngDownload
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#1
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18 Reply
Re:DoH (DNS over HTTPS) failure blocks entire internet connection (No Fallback)
Friday - last edited Friday

  @Dipto-K 

 

As can be seen from this FAQ, for AC series models (like Archer C64), DoH is implemented only in Ultra Secure Mode (DNS mode).

The feature you're referring to, is implemented for AX series models. From that perspective, this sounds more like a feature request.

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#2
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Re:DoH (DNS over HTTPS) failure blocks entire internet connection (No Fallback)
Friday

  @terziyski I didn't request for any new feature. DoH is already there in archer c64. Can you please read my post again. 

 

The issue is that when DoH fails to connect to the selected server, the internet gets blocked. There should be a fallback.

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#3
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Re:DoH (DNS over HTTPS) failure blocks entire internet connection (No Fallback)
Friday

  @Dipto-K 

 

Can you post a screenshot of your DoH settings here ?

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#4
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Re:DoH (DNS over HTTPS) failure blocks entire internet connection (No Fallback)
Saturday - last edited Saturday

 

 

@terziyski 

When it fails to connect to the server the internet doesn't work and I have to turn it off manually.

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#5
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Re:DoH (DNS over HTTPS) failure blocks entire internet connection (No Fallback)
Saturday

  @Dipto-K 

 

On AX and BE series router models there is a so-called DNS mode option:

 

If you set the DNS mode to Default Mode, you'll get the behavior you're asking for (unencrypted DNS fallback):

 

The DNS mode option is not implemented in Archer C64 and when you enable the DoH feature, it defaults to Ultra Secure Mode.

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#6
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Re:DoH (DNS over HTTPS) failure blocks entire internet connection (No Fallback)
Saturday

  @terziyski so should I stop using DoH in my archer c64?

 

Because I don't see any other way. When selected DoH server fails the internet doesn't work, it's a feature when there is no error but on error everything is broken.

 

And my suggestion would be, please when you provide a feature make sure it's properly implemented or don't provide it.

 

 

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#7
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Re:DoH (DNS over HTTPS) failure blocks entire internet connection (No Fallback)
Saturday - last edited Saturday

  @Dipto-K 

 

The DNS Mode  feature is not implemented in AC series router models - that's why I believe this should be more like a feature request.

BTW, what are your Internet DNS settings:

 

 

and LAN DNS settings:

 

 

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#8
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Re:DoH (DNS over HTTPS) failure blocks entire internet connection (No Fallback)
Saturday

  @terziyski 

Primary: 1.1.1.1

Secondary: 1.0.0.1

It's my dns setup.

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#9
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Re:DoH (DNS over HTTPS) failure blocks entire internet connection (No Fallback)
Saturday - last edited Saturday

  @Dipto-K 

 

That's on the LAN side, correct ? What they are from the Internet side — check my first screenshot in the previous post.

You can have two different DNS settings — one for the Internet connection and another for your LAN connected devices (these are optional).

I am asking this because if there's no DNS Mode setting in C64, I would assume that the Default Mode should apply (with a fallback to the regular DNSs).

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#10
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Re:DoH (DNS over HTTPS) failure blocks entire internet connection (No Fallback)
Saturday - last edited Sunday

  @terziyski I set the dns on internet side.

 

I think the fallback to regular dns after DoH failure isn't working.

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#11
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Replies: 18

Tags

Network Connectivity DoH/DoT