DNS: Name servers are often also resolving name servers—they perform every step necessary to answer any DNS query they receive. To do this the name server queries each authoritative name server in turn, starting from the DNS root zone. It continues until it reaches the authoritative server for the zone that contains the queried domain name. That server provides the answer to the question, or definitively says it can't be answered, and the caching resolver then returns this response to the client that asked the question.The authority, resolving and caching functions can all be present in a DNS server implementation, but this is not required: a DNS server can implement any one of these functions alone, without implementing the others.Internet service providers typically provide caching resolvers for their customers. In addition, many home networking routers implement caching resolvers to improve efficiency in the local network.Google Public DNS is a freely provided closed-source DNS (Domain Name System) service announced on 3 December 2009,as part of Google's, self-proclaimed, effort to make the web faster.[2][3] Google Public DNS provides the following recursive nameserver addresses for public use, mapped to the nearest operational server location by anycast routingGoogle Public DNS is a freely provided closed-source DNS (Domain Name System) service announced on 3 December 2009, as part of Google's, self-proclaimed, effort to make the web faster.Google Public DNS provides the following recursive nameserver addresses for public use,mapped to the nearest operational server location by anycast routing. Users can activate Norton DNS by setting their DNS server addresses to the Norton DNS servers (hosted at 198.153.192.1 and 198.153.194.1). Client software for Windows and Mac OS X is also available that can automatically configure these settings. A similar client is available for Android mobile phones through the Android Market.DNS queries routed through Norton DNS are checked with the Norton Safe Web database to ensure that they do not point to malicious websites. Symantec thus seeks to block malware and phishing attempts.Norton DNS will also intercept misspelled domain names and offer suggestions or display advertising.
