@Wobbo 

This is one of commonly used methods to check if device has Internet access.

I am not saying it is the best one or it is the right one, just explaining what you see.

Thanks @Alexandre for that information.

A router never establishes and should never check the internet connection itself. Can you turn this function off.

How long does TP-link take to respond?

@Wobbo I have a Deco M9+ and several Raspberry PIs. Can you please explain exactly how you did this observation? What did you run to get this log? I might want to check it myself. I also care about privacy, and I don't use any of those mentioned sites for that reason. 

It would be interesting to see if this can be observed from here, and equally interesting if it can't. 

Wobbo wrote

A router never establishes and should never check the internet connection itself.

@Wobbo 

Belkin N-series WiFi routers do check the Internet connection, for example. I used to own Belkin N150 long time ago, it were wired to ISP cable modem. Every time my ISP cable modem lost its Internet connection, N150 status light would switch from Solid Blue to Blinking Amber. 

It is convenient feature. All I need to do is look at the top of Deco M9 I have, if its LED light switched from green to red I know Internet is down in my household.

@Alexandre. 

That sounds nice, but I am not happy with it. There is nowhere to be found that TP-link makes contact with companies such as Linkedin and Facebook. In addition, you cannot change or turn it off anywhere. As soon as I connect to these companies, they know my IP address. This is very interesting to them. There is no need for a router. The Deco use these patches to indicate that they have a connection with the Main Deco. The Main-Deco also connects to TP-Link for time zone. This should be enough. In addition, it is not necessary to make an endless connection as you can see in my attachment. This indicates that TP-Link is claiming for third party forwarding this data.

@Wobbo 

Agreed, that could have been done better. Check this forum conversation.

@cacb, I am using an RPi 3 with OS Lite with Pi-hole.org. I don't need the Desktop for this. You can only set the OS Lite via the Terminal. If you install the Lite, you will initially have a screen and keyboard (mouse not required). The Desktop OS is also possible.

For now the latest version https://downloads.raspberrypi.org/raspios_lite_armhf/images/raspios_lite_armhf-2020-12-04/2020-12-02-raspios-buster-armhf-lite.zip

Then when RPi OS is installed go to the website for the latest version https://github.com/pi-hole/pi-hole/#one-step-automated-install

In the Deco app you have to find the IP address of the RPi and set it that the IP cannot be changed. You must use this IP address DHCP. You need to replace the Primary DNS to this number. Do not empty the Secondary number. If it is empty then create one, for example 9.9.9.9 (Quad9) or (Google). If the RPi fails, you will not get any problems.

When this is off, go to the locked IP address in your browser. On the website they explain that you are in the terminal
"sudo pihole -a -p" creates a password.

Pi-hole is very out of use but would work right away. Now the page http://192.168.*.*/admin/settings.php?tab=dns is interesting. Here you can determine which DNS the Pi hole uses.

This is what I use to display the url: Query Log http://192.168.*.*/admin/queries.php

@Wobbo Thank you, I will look into it.

@cacb They don't do anything at all. I expected that. TP-link does not answer and ignores topics like this.