OpenDNS is a company provide DNS resolution service acquired by Cisco On June 30, 2015(https://www.opendns.com/).OpenDNS provides the following recursive name server addresses for public use.
OpenDNS also provides the following recursive nameserver addresses as part of their FamilyShield parental controls which block pornography, proxy servers, and phishing sites:
OpenDNS supports the DNSCrypt protocol, which authenticates DNS traffic between the user’s computer and the name servers.This requires installing free software onto supported devices.
Similar service providers
Norton ConnectSafe is a free public DNS service offered by Symantec Corporation.
Policy A — Security
This policy blocks all sites hosting malware, phishing sites, and scam sites. To choose Policy A, use the following IP addresses as preferred and alternate DNS server addresses:
Policy B — Security + Pornography
In addition to blocking unsafe sites, this policy also blocks access to sites that contain sexually explicit material. To choose Policy B, use the following IP addresses as preferred and alternate DNS server addresses:
Policy C — Security + Pornography + Non-Family Friendly
This policy is ideal for families with young children. In addition to blocking unsafe sites and pornography sites, this policy also blocks access to sites that feature mature content, abortion, alcohol, crime, cults, drugs, gambling, hate, sexual orientation, suicide, tobacco, or violence. To choose Policy C, use the following IP addresses as preferred and alternate DNS server addresses
FreeDNS is an open, free and public DNS Server(http://freedns.zone/en/).
Google Public DNS(https://developers.google.com/speed/public-dns/)
IP addresses 18.104.22.168 and 22.214.171.124