can someone help with configuration of DNS server? I have problems connecting to any legit site.

Use one of the following free public DNS servers:

IPv4 Primary / Secondary

IPv6 Primary / Secondary

Cloudflare: IPv4: 1.1.1.1 / 1.0.0.1 IPv6: 2606:4700:4700::1111 / 2606:4700:4700::1001 

Google: IPv4: 8.8.8.8 / 8.8.4.4 IPv6: 2001:4860:4860::8888 / 2001:4860:4860::8844

Quad9: IPv4: 9.9.9.9 / 149.112.112.112 IPv6: 2620:fe::fe / 2620:fe::9

OpenDNS: IPv4: 208.67.222.222 / 208.67.220.220 IPv6: 2620:119:35::35 / 2620:119:53::53

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