Free Public DNS servers

Free public DNS servers include Google, Quad9, OpenDNS, Cloudflare, CleanBrowsing, Verisign, Alternate DNS, AdGuard DNS, etc.

Here’s a short list of some of the most popular ones:

IPv4

OpenDNS (208.67.220.220,  208.67.222.222)
Google Public DNS (8.8.8.8, 8.8.4.4)
Cloudflare (1.1.1.1, 1.0.0.1)).

IPv6

OpenDNS 2620:0:ccc::2 and 2620:0:ccd::2
Google 2001:4860:4860::8888 and 2001:4860:4860::8844
Cloudflare 2606:4700:4700::1111 and 2606:4700:4700::1001.