Human-readable names like "linuxpoison.blogspot.com" are easy for people to remember, but they don't do machines any good. All of the machines use names called IP addresses to refer to one another. For example, the machine that humans refer to as "linuxpoison.blogspot.com" has the IP address 126.96.36.199. Every time you use a domain name, you use the Internet's domain name servers (DNS) to translate the human-readable domain name into the machine-readable IP address. Speeding up DNS lookups is one of the simplest, and most effective ways to speed up browsing.
Namebench. hunts down the fastest DNS servers available for your computer to use. namebench runs a fair and thorough benchmark using your web browser history, tcpdump output, or standardized datasets in order to provide an individualized recommendation. namebench is completely free and does not modify your system in any way. This project began as a 20% project at Google.
namebench runs on Mac OS X, Windows, and UNIX, and is available with a graphical user interface as well as a command-line interface.
Download NameBench from here
Go to terminal (root) and type following command to install and run NameBench:
tar -zxvf namebench-1.0.5.tgz
python setup.py install
namebench will test the nameservers your machine is currently using, plus the popular global DNS services, and the best 4-6 additional name servers that it can find for you. It will output some text-graphs and URL's for more a more detailed performance analysis of each nameserver.
If you want to specify an additional set of name services, simply add the IP to the command-line, or edit namebench.cfg:
./namebench.py 10.0.0.1 192.168.0.1
Here are my DNS server test results: