DNS level security system is one of the easiest ways to implement. No need to update the signatures locally. Because all the updates happening in server side itself. And the main advantage I noticed is there is no softwares ( client application ) required.
Open DNS is secured DNS service, In addition they launched a new service called Family Shield, it protects Kids from adult websites. By implementing OpenDNS in gateway level (Roters / wi fi hotspots ) it can protect all devices like ipad, cell phones connected to the gateway. In addition to adult sites filtering it also blocks phishing sites, Proxy sites, virus/malware websites.
Only thing you have to do is set your Primary and secondary DNS Ip address as Open DNS Family Shield Ip address
Open DNS FamilyShield IPs
Open DNS IPs