Flush DNS: Everything You Need to Know

When you browse the internet, your computer relies on a Domain Name System (DNS) server to convert website addresses into IP addresses. This process allows you to access websites without having to remember a string of numbers. However, your computer stores DNS information in a cache to speed up future requests. In some cases, this cache can cause issues, such as outdated information or potential security threats. Flushing your DNS cache is a simple yet effective solution to these problems. we’ll explore what flushing DNS does, why you might need to do it, and how to flush DNS on different operating systems.

How to Flush DNS on Windows

Flushing DNS on Windows is a straightforward process. The exact steps may vary slightly depending on your version of Windows. Here’s how to flush DNS on Windows 10, 8.1, 8, and 7:

1. Press the Windows key on your keyboard or click the Start button.
2. Type Command Prompt in the search bar.
3. Right-click on the Command Prompt app and select Run as administrator. If prompted for permission, click Yes.
4. In the Command Prompt window, type the following command:
   ipconfig /flushdns
5. Press Enter to execute the command.
6. After the command is successfully executed, you should see a message stating “Successfully flushed the DNS Resolver Cache.”

How to Flush DNS on macOS

Flushing DNS on macOS requires using the Terminal application. The steps may vary depending on the version of macOS you are using. Follow these instructions to flush DNS on macOS Catalina and later:

1. Press Command + Space on your keyboard to open Spotlight.
2. Type Terminal and press Enter to open the Terminal application.
3. In the Terminal window, enter the following command:
   sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder
4. Press Enter and provide your administrator password when prompted.
5. After the command is executed, there won’t be any confirmation message. You can now check if the problematic website loads correctly.

For older versions of macOS, check the specific command for your operating system version.

How to Flush DNS on Linux

Flushing DNS on Linux may vary depending on the distribution you are using. Here are generic steps that should work for most Linux systems:

1. Open the terminal application. You can usually find it in the applications menu or by pressing Ctrl+Alt+T on your keyboard.
2. In the terminal, enter the appropriate command based on the DNS service your Linux system is running:

• NCSD: sudo /etc/init.d/nscd restart
• Dnsmasq: sudo /etc/init.d/dnsmasq restart
• BIND: Try one of the following commands:
  • sudo /etc/init.d/named restart
  • sudo rndc restart
  • sudo rndc exec

1. You may be prompted to enter your password.
2. The DNS service may stop and start again, but there won’t be a confirmation message. You can now test the problematic website.

Please note that Linux distributions may use different DNS services, so it’s essential to check for specific instructions for your particular distribution.

How to Clear DNS Cache on Chrome

If you primarily use Google Chrome as your web browser, it has its own DNS cache that you may need to clear in addition to your computer’s DNS cache. Here’s how to clear the DNS cache on Chrome:

1. Launch Google Chrome on your desktop.
2. In the address bar, enter chrome://net-internals/#dns.
3. Click the Clear host cache button.
4. The DNS cache for Chrome will be cleared, and you can now test the website again.

Clearing the DNS cache in your browser can help resolve issues specific to Chrome, such as outdated DNS records or misconfigured settings.

What is DNS Cache?

Before we dive into the details of flushing DNS, let’s understand what DNS cache is. When you visit a website for the first time, your computer sends a request to a DNS server to obtain the IP address associated with the website’s domain name. The DNS server responds with the IP address, allowing your computer to establish a connection and load the website. To improve performance, your computer stores this information in a cache called the DNS cache. The next time you visit the same website, your computer can retrieve the IP address from the cache instead of making a new request to the DNS server. This speeds up the process and reduces server response times.

What Does Flushing DNS Do?

Flushing DNS clears the DNS cache on your computer, removing any stored IP addresses or DNS records. This action forces your computer to retrieve fresh information from the DNS server the next time you visit a website. Flushing DNS can be beneficial in several situations:

1. Resolving Security Issues: DNS cache poisoning, also known as DNS spoofing, is an attack where malicious actors manipulate the DNS cache to redirect users to fraudulent websites. Flushing DNS can help prevent such attacks by clearing any potentially compromised entries.
2. Fixing Website Access Problems: If you encounter difficulties accessing a website, such as receiving a 404 error or being redirected to the wrong site, clearing the DNS cache may resolve the issue. It ensures that your computer fetches the latest IP address associated with the website.
3. Improving Internet Connectivity: In some cases, an outdated or corrupted DNS cache can disrupt your internet connection. Flushing DNS can help rectify connectivity problems by starting with a clean slate.
4. Protecting Privacy: The DNS cache can contain information about the websites you’ve visited, potentially compromising your privacy. Regularly flushing DNS clears this information, keeping your browsing habits more private.

Conclusion

Flushing DNS can be a useful troubleshooting step when you encounter website access problems, security concerns, or internet connectivity issues. By clearing your computer’s DNS cache, you ensure that it retrieves the most up-to-date information from the DNS server. Whether you’re using Windows, macOS, Linux, or Chrome, the process is relatively simple. Remember to exercise caution when making changes to your computer’s settings and only flush DNS when necessary.