To flush your DNS cache in WINDOWS simply perform the following steps:

1. Open command prompt window. (Start/Program Files/Accessories/Command Prompt) OR (Start -> Run -> type cmd)
2. Enter "ipconfig /flush dns" at the command prompt.(C: >)

A confirmation window should then appear confirming a successful flush.

Example:
C:Documents and SettingsJohn>ipconfig /flushdns
Windows IP Configuration
Successfully flushed the DNS resolver Cache.
The screen will then return to the initial command string:
C:Documents and SettingsJohn>

To flush your DNS cache in LINUX simply perform the following steps:

* Restart the nscd daemon: Enter "etc/rc.d/init.d/nscd restart" in your command terminal
Once you run this command in linux, your DNS cache will be flushed.

To flush your DNS cache in Mac OS X simply perform the following steps:

* Enter "lookupd -flushcache" in your command terminal
Once this command is run in Mac OS X, your DNS cache will be flushed.