What is DNS and DNS Flushing – when and why to do?

DNS is the Domain Name System. Basically, DNS servers convert a domain name into an IP address (for example – DNS maintains a huge distributed database of networks and address and it provides a way to determine the corresponding IP address to the domain name.

All public website runs over the internet with a public IP address. Internet uses DNS as worldwide name resolutions for public websites. when we type any domain address in a web browser then DNS finds the corresponding IP address for the domain name and data required to make the connection between browsers and web servers.

When we access any website via the browser, our computer keeps the record of DNS for future use. It is called  DNS cache. We can delete DNS records by flushdns command. DNS flush is very useful when a website moved servers and if we are seeing the old website again then flushing cache can help.

Sometimes, we started to see timeout error messages or when we type any web address and find the website does not exist or browser moves us to search page. Even the computer restart does not help in this case. It is due to recent changes in website servers or name servers. DNS flush can helps in this case.

So, DNS (Domain Name System) stores domain name and information relevant to a specific domain name in the cache. The purpose of this cache to speed up the process when the user will come next time to visit the same website. But, if the DNS information of a website has changed, then the information stored in a computer’s DNS cache will have to be updated as well, or else the user will face several problems in accessing the website. This can be done by flush DNS cache and the updated DNS information will be stored in its place again when the user will access the website.

Type the following within the command prompt to flush DNS: ipconfig /flushdns.

ipconfig /displaydns – The /displaydns option outputs a list of the name-to-IP mappings currently in the cache.


ipconfig /flushdns – This option simply empties the local DNS cache. Nothing more, nothing less. Flushing the cache can be useful in certain network troubleshooting situations.
ipconfig /registerdns – This one does not relate to the local cache. The /register dns option contacts the DNS server (as configured in the system’s TCP/IP settings), and tells the server its current IP address. This is useful when the DNS server is, for whatever reason, not updating correctly.


Leave a Reply