Dns Safety is a DNS forwarding server (like dnsmasq) with extensive filtering capabilities. It allows administrator to filter access to domain names by categories, easily block access to user specified domains and provides different access policies for different groups of machines in your network.
Dns Safety is supposed to be deployed as primary DNS server in your local network and can forward DNS requests to your ISP's DNS server, Google Public DNS, OpenDNS and other third party DNS providers.
See more information at https://www.diladele.com/dnssafety/