How to clear your DNS cache (Flush DNS)
Most operating systems and DNS clients will automatically cache IP addresses and other DNS results in order to speed up subsequent requests to the same hostname. Your DNS cache stores the locations (IP addresses) of web pages you have recently viewed. If the location of the page changes before the entry in your DNS cache is updated, you will be unable to access the page.
If you are encountering a high number of HTML Error 404 codes, you may need to flush your DNS cache. Once you clear your DNS cache, your computer will query nameservers for the new DNS information rather than relying on old information stored on your computer.
Here is how to flush your DNS resolver cache. You may need administrator rights to perform this action.
In Windows Vista/7/8, go to the start button and type “cmd” in the Search panel, then press Enter. Otherwise navigate via Start > All Programs > Accessories > Command Prompt.
In Windows 98/NT/2000/XP, navigate via Start > Run, press “cmd.exe” and press OK.
In the command prompt, type “ipconfig /flushdns”
You will receive a message confirming that the DNS cache has been flushed:
The resolver cache has been cleared.
Close the command prompt.
Mac and Linux:
Instructions for completing the same procedure on Macintosh and Linux systems can be found here.