DNS Servers 'completely free'

The DNS server provides you service, not software. The free/proprietary dichotomy does not apply to services. However SaaSS is a great threat to our freedoms: https://www.gnu.org/philosophy/who-does-that-server-really-serve

But using somebody's else DNS server is not SaSS because maintaining the ip-name mapping is not your "own computing".

You can run your own DNS server though. Or you can simply choose one that does not lie (typically for censorship purpose) and does not represent a high privacy risk (not Google's...). If you are in a country that does not ask its Internet Providers to censor the Web (such as China or France or...), then their DNS servers probably are OK.

Thanks.

So I should run my own DNS server.

How can I do that? Do I need a computer always on? ...

And which IP numbers do I have to put into my router (primary and secondly dns servers)?

I live in Spain. Which DNS servers would you recomend me?

Thanks. I am a dummy. :|

If you only need DNS servers instead of your ISP ones you should familiar with OpenNIC that is an alternate network information center/alternative DNS root which lists itself as an alternative to ICANN and its registries.

https://www.opennicproject.org/

Check your the nearest DNS servers

https://www.opennicproject.org/nearest-servers/

Or look them up in the following list

https://servers.opennicproject.org/

In addition, it worth checking what DNSCrypt is because it improves DNS security

https://www.dnscrypt.org/

Un saludo,

I hear openic is good