Opendns – https://www.opendns.com, is a suite of public dns than can make your home internet safe.
The service offered by Cisco can cover also business use.
The service is free of charge for home using, you can configure the dns server on your home router, your personal computer or on your mobile device.
DNS server : 18.104.22.168 / 22.214.171.124
There are also some charged service. Visit https://www.opendns.com.