Computer operating systems can persistently maintain DNS cache after consistently connecting to a site or accessing a domain (hostname). This can produce errors when accessing domain related resources, such as website and email, when your DNS has been updated and IP addresses are changed.
To address this issue, close the programs (browsers, mail clients, etc.) restart your computer and use the following instructions to clear your DNS cache.
The “IPConfig” program in Windows displays current TCP/IP network configuration values and displays, registers, or flushes Domain Name System (DNS) names. To access IPConfig you’ll need to open Command Prompt:
– Programs -> Accessories -> Command Prompt
– or Start -> All Programs -> Accessories -> Command Prompt
– or at the “Run” menu type “cmd” and [Enter]
At the command prompt enter the following syntax:
(if done successfully it will respond with “Successfully flushed the DNS resolver Cache”)
To verify your computer is “seeing” the correct IP address for your resource you can then type “ping www.yourdomain.com” and see if a Ping returns the correct IP address.
NOTE: in some Windows configurations with “UAC” permissions enabled you might get a prompt that says: “the requested operation requires elevation” This means the cmd prompt must be run “as administrator”. Optionally before launching the cmd prompt, Right-click on its icon and select “Run as administrator“.
On Mac OS X:
You will open and use the Terminal application see: