What is a DNS Cache and How it Works?

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By Susith Nonis

Do you know what DNS cache is? Have you ever cleared your DNS cache?

If not, don’t worry we will tell you about the DNS cache along with the reasons why you need to clear it.

Clearing DNS cache is a troubleshooting tip that allows you to get the updated IP address of a website. It is important to remove the old IP address associated with a domain and replace it with the new one. To make it happen, you simply need to clear the DNS cache.

DNS (Domain Name System) communicates with the browser and provides the IP address of the particular website that you are trying to visit. Your computer system stores the DNS data in its cache to point web browsers to the right IP address.

What is DNS Cache?

DNS Cache is temporary storage maintained within your computer system. It contains the address data of websites you visit regularly. In simple words, DNS cache is just a memory of recent DNS lookups which your system can refer to while accessing a website.

When you enter a website in your browser, your computer searches for DNS information in the local cache, and then it uses DNS cache to access the website faster. Whereas, if the data or IP address of the website is not stored on the local DNS cache, then the web browsers will fetch the IP address from other public DNS servers.

How DNS Cache Works?

Before the web browser issues any requests to the external network, the computer system intercepts each request and searches for the domain in the database of DNS cache. The DNS Database contains the latest domains and their associated IP addresses.

If the IP address of a website gets changed, the DNS information might not update on your computer instantly and you may be redirected to the old IP address. While DNS cache will get updated automatically, it may take some time for changes to reflect. Meanwhile, you may experience difficulty in visiting websites that have new IP addresses assigned to their domain names. However, by clearing the DNS cache, you can speed up the process of updating the DNS database on your computer with new values.

Now, let’s discuss how to flush DNS cache on Windows, macOS, and the Chrome web browser.

Steps to clear DNS cache on macOS

  1. Launch the terminal application first. You will find it in the launchpad under the ‘other’ folder. You may even think about launching it by opening Finder and going to Applications > Utility folder.
  2. It will then launch the terminal window in which you need to input the command – sudo killall -HUP mDNSResponder
  3. After this, you need to input your macOS account password.
  4. Your computer system will then flush the DNS cache. Now, you have to visit websites to get updated DNS details.

Steps to clear DNS Cache on Windows

  1. Click the start button and open the command prompt application.
  2. Within the command prompt window, you need to input the command – ipconfig / flushdns.
  3. Click the enter button for the command to execute and Windows will clear the DNS cache.
  4. Visit websites to acquire the latest DNS information.

Steps to clear DNS Cache on Chrome Browser

  1. Enter this address chrome://net-internals/#dns in the address bar and press enter.
  2. It will load Chrome’s net internal settings page. Now, click on the Clear Host Cache button and Chrome will flush the DNS Cache.
  3. Remember that DNS Cache is stored separately from the web browser cache.
  4. You can now visit a website and get the latest DNS details.


All in all, DNS Cache helps to skip DNS lookup every time you visit a website and makes it possible to access websites faster. In case, you need to clear your DNS cache, you need to follow the steps mentioned above and you will be good to go.

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