How to change or setup DNS server IP address
Visit below mentioned site to setup DNS as per your operating system:
Namebench Helps You Find the Fastest DNS Server for Your Computer
After you download and fire up namebench, just click the Start Benchmark button to test out a handful of free public DNS services, from Google Public DNS to OpenDNS to UltraDNS. Once started, the test took about 12 minutes to complete using the default settings. When it’s done, you’ll be presented with a handful of handy charts displaying the results of the tests.
You can see the results to my test in the screenshots above and below. From the looks of things, UltraDNS is the DNS that’s going to do the most to speed up my connection. In fact, it claims UltraDNS will be 46% faster than Google Public DNS (the DNS server my computer was using when I ran the test)—so it looks like I may just be switching yet again.
Nambench is a free, open-source download, works with Windows, Mac OS X, and Linux. If you give it a try, let’s hear what DNS server scores highest for you in the comments.