Iโve also used the servers at OpenDNS 208.67.222.222 and 208.67.220.220. OpenDNS provides a secure and safe DNS service which I recommend that you check out for home and commercial use. Norton Connectsafe also have secure DNS servers for home users at 198.153.192.1 and 198.153.194.2 that respond to ICMP requests or try to visit my thread nalang https://phcorner.org/t/dns-and-what-is-dns.374720/