1. To view the DNS cache, open a command prompt and enter the following command: ipconfig /displaydns
2. If this computer has been used to resolve host names with IP addresses—for example, if it has been used to retrieve mail or browse the Web—a list of locally cached resource records appears. Read the file to see what kinds of records have been saved, using the scroll bar if necessary. How many are A records and how many are a different type, such as CNAME?
3. Next clear the DNS cache with this command: ipconfig /flushdns The operating system confirms that the DNS resolver cache has been flushed. One circumstance in which you might want to empty a client’s DNS cache is if the client needs to reach a host whose IP address has changed (for example, a Web site whose server was moved to a different hosting company). As long as the DNS information is locally cached, the client will continue to look for the host at the old location. Clearing the cache allows the client to retrieve the new IP address for the host.
4. View the DNS cache again with the command: ipconfig /displaydns Because you just emptied the DNS cache, you will receive a message that indicates that Windows could not display the DNS resolver cache.