The job of a DNS server is to translate domain names (like google.com) into IP addresses (like 209.85.135.103) and it does this for every new new site that you visit in the browser. Therefore, no matter how fast your Internet connection speed is, a site won’t load unless the DNS server has performed the lookup successfully.

When it comes to choosing a DNS server, you’ve several choices. There are public DNS services like OpenDNS and Google DNS or you could use the DNS Server of your ISP itself. To find your current DNS server, type ‘ipconfig /all’ at the command prompt and look for the “DNS Server” entry under Ethernet adapter.

The speed at which a DNS server can resolve domain names into IP addresses depends on its geographic location among other factors. Therefore, for example, OpenDNS could be the fastest performing DNS server for a user in location A but Google DNS could be a better choice for another user in location B. This also explains why your ISP’s DNS Server may perform faster in some cases.

f you would like to know which is the fastest DNS Server for your computer, there’s a free utility called namebench that can help. namebench runs on Mac OS X, Windows, and UNIX, and is available with a graphical user interface as well as a command-line interface.

Most DNS services offer resolvers at two IP address – for instance, Google DNS is available at 8.8.8.8 and 8.8.4.4 – and they are used in the same order in which they are listed in your network settings.

You should therefore look at the performance of individual DNS servers and set the “Preferred DNS Server” as the one that has the lowest score. In fact, you may also mix servers – like you can use Google Public DNS as the Preferred DNS server and OpenDNS as your Alternate DNS server.

Steps

1. Download either  http://www.grc.com/dns/benchmark.htm or  http://code.google.com/p/namebench/
2. Run the benchmarks
3. Open up network settings, then adapter settings and double click on your local area connection
4. Choose properties and double click on internet protocol version 4
5. Select "Use the following DNS servers" and then put in the address given as the fastest from either benchmark