Cloudflare Free DNS Servers

Protect your home against malware – Using the following DNS resolvers will block malicious content:

IPv4

1.1.1.2
1.0.0.2

IPv6

2606:4700:4700::1112
2606:4700:4700::1002

Protect your home against malware and adult content – Next DNS resolvers for Families will block malware and adult content:

IPv4

1.1.1.3
1.0.0.3

IPv6

2606:4700:4700::1113
2606:4700:4700::1003

https://developers.cloudflare.com/1.1.1.1/1.1.1.1-for-families

OpenDNS (Cisco-owned)

OpenDNS Family Shield, FREE – Preconfigured to block adult content

IPv4

208.67.222.123
208.67.220.123

https://www.opendns.com/setupguide/#familyshield

Quad 9

An open DNS recursive service for free security and high privacy – Malware Blocking, DNSSEC Validation

IPv4

9.9.9.9
149.112.112.112

IPv6

2620:fe::fe
2620:fe::9

https://www.quad9.net/service/service-addresses-and-features/

AdGuard DNS server

If you want to block ads and trackers:

IPv4:

94.140.14.14
94.140.15.15

IPv6:

2a10:50c0::ad1:ff
2a10:50c0::ad2:ff

Block adult content, enable safe search and safe mode options wherever possible, and also block ads and trackers.

IPv4:

94.140.14.15
94.140.15.16

IPv6:

2a10:50c0::bad1:ff
2a10:50c0::bad2:ff

https://adguard-dns.com/en/public-dns.html