Why don't the dns server addresses change?

1) Why can't I just change the dns via a network card or the ethernet settings of the router (you can change it, only the Internet doesn’t work after that)?

2) And why when turning on Yandex dns in the settings of the router, the provider dns still remain? How to remove them? And how to understand to which of the dns of the table there will be a connection to a Yandex or provider?

I suspect that before reaching out to Yandex, you need to get its DNS addresses - this is what the DNS provider does. DNS hierarchical system, read here . Without an intermediate DNS you can not reach higher.

3) And is there any point in changing dns, will the Internet be faster to load?

I suspect no. Optimization is in a much larger number of places. The speed of loading pages rests on the width of the channel, the speed of the browser, the speed of the OP and so on.

4) Are there any local dns, so that I have an updateable database on my computer and the connection goes right to the ip-address (this way it will be faster to load)?

What's the point? any change will have to pump the entire base. You will never turn to many of the elements of the base, and the load on the channel will be large.

In addition, the entire CSN system is built and taking into account the protection of information from the substitution. Downloading, you cannot guarantee the accuracy of the answer and cannot be sure that you have not been replaced when downloading an ip-address.

I also advise you to read the relevant chapters from the book “Modern Operating Systems” by Andrew Tanenbaum

1) Why can't I just change the dns via a network card or the ethernet settings of the router (you can change it, only the Internet does not work after that)?

through the network card of your computer / laptop almost always can be changed. But why the Internet does not work - it is necessary to understand. It may incorrectly indicate or the provider blocks them (and why not). You can just try to ping them.

2) And why when turning on Yandex dns in the settings of the router, the provider dns still remain? How to remove them? And how to understand to which of the dns of the table there will be a connection to a Yandex or provider?

This is the specificity of your router.

3) And is there any point in changing dns, will the Internet be faster to load?

Yes, sometimes it makes sense. But for starters, I would ping the dns provider and look at the response. It happens that the provider is crookedly adjusted. And in this case, the Internet will work very poorly, even with a wide channel.

But there are dns servers that give different ip addresses depending on who came to them. Thus, for example, Google works. And if you specify the wrong dns, you can transfer to resources in the United States when you have your own local, fast ones.

4) Are there any local dns, so that I have an updateable database on my computer and the connection goes right to the ip-address (this way it will be faster to load)?

Yes. In the windows world I won’t say, but there is a bind in Linux that can be customized or embedded in many dnsmask distributions. But only they do not deflate the entire base - it is large and frequently updated. They just make transparent caching. Five years ago it was justified. Now the browsers themselves are able to very effectively cache dns requests and additional layer to nothing.

Many routers themselves are able to cache dns requests. For example, asus. And devices connected to it as dns give their ip.

You also need to understand that many OS do not know how to correctly handle the situation when many dns servers are set and take the first 2.