Google DNS : Google, about half a year ago, entered the world of DNS servers, to have high-performance servers that use, in order to improve the browsing experience for Google users. To use Google DNS, use the IP address 22.214.171.124 (primary DNS) and 126.96.36.199 (Secondary DNS).
OpenDNS : Another alternative to your ISP, OpenDNS is a great alternative because it includes several filters which can be configured to block unsafe web sites or explicit content. Ideal for schools and businesses. To use your server: 188.8.131.52 (Primary DNS) and 184.108.40.206 (Secondary DNS).
Advantage DNS : Advantage DNS resolves all DNS requests through the UltraDNS Directory Services Platform, thus substantially improves navigation. 220.127.116.11 (Primary DNS) and 18.104.22.168 (Secondary DNS).
ScrubIT : And the last alternative is ScrubIT, a DNS server that regulates the connection filter disallowing dangerous websites. 22.214.171.124 (Primary DNS) and 126.96.36.199 (Secondary DNS).