How to Flush cache in Windows?
1.Open Command Prompt(Start->Run , type cmd and hit enter).
2.In command promt type
ipconfig /flushdns
3.hit enter
Your DNS cache is cleared now, try to load your new website.
How to Clear Cache in Linux?
First of all you have to install nscd . (only 250kb).
Open terminal and type
sudo apt-get install nscd
Type this command to restart the DNS cache server in Linux:
sudo /etc/rc.d/init.d/nscd restart
How to Clear Cache in Mac Os?
Open the Terminal
Type the following command:
dscacheutil -flushcache
출처 : http://expertsbench.blogspot.kr/2012/08/how-to-clearflush-dns-cache-in.html