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DNS flush

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by

Amit Kohli
in

DNS flush refers to the process of clearing the DNS (Domain Name System) cache on your computer or server. The DNS cache stores the IP addresses of web servers that contain recently visited websites. When you clear (or flush) the DNS cache, it forces your system to remove all stored entries, which may include outdated or incorrect information.

Why DNS Flush?

Flushing the DNS cache can be necessary for several reasons:

  1. Outdated Information: If the DNS cache contains outdated information (like old IP addresses), you may experience difficulties accessing websites that have recently changed their IP address or hosting provider.
  2. Resolve Connection Issues: Sometimes, flushing the DNS can resolve connectivity problems, especially if a site isn’t loading correctly or at all.
  3. Privacy: Clearing the DNS cache can remove any stored information about previously visited sites, which can be a privacy measure.
  4. Resolve DNS Spoofing/Poisoning Issues: In cases of DNS cache poisoning, where malicious entities provide incorrect DNS information, flushing the DNS cache can remove the harmful data.

How to DNS Flush Cache on Different Operating Systems

Here’s how you can flush the DNS cache on various operating systems:

1. Windows

For Windows 10/11:

  1. Press Win + R to open the Run dialog box.
  2. Type cmd and press Enter to open the Command Prompt.
  3. In the Command Prompt window, type the following command and press Enter:bashCopy codeipconfig /flushdns
  4. You should see a message saying: “Successfully flushed the DNS Resolver Cache.”

2. macOS

For macOS Monterey (12.0) and later:

  1. Open the Terminal application (you can find it using Spotlight or in the Applications > Utilities folder).
  2. In the Terminal window, type the following command and press Enter:Copy codesudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder
  3. You may be prompted to enter your administrator password. After entering it, the DNS cache will be flushed.

3. Linux

For most Linux distributions (like Ubuntu):

  1. Open the Terminal.
  2. Depending on your distribution, you may need to restart the nscd service, which manages the DNS cache.Copy codesudo systemctl restart nscd Or, if you’re using a different service for DNS caching, such as dnsmasq or systemd-resolved, you might use:Copy codesudo systemctl restart dnsmasq Or:Copy codesudo systemctl restart systemd-resolved
  3. The DNS cache should be flushed.

4. Google Chrome (Internal DNS Cache)

If you’re using Google Chrome and want to flush its internal DNS cache:

  1. Open Google Chrome.
  2. In the address bar, type chrome://net-internals/#dns and press Enter.
  3. Click the “Clear host cache” button to flush the DNS cache within Chrome.

Conclusion

DNS flush cache is a straightforward process that can help resolve various connectivity issues, ensure you’re accessing the most up-to-date information online, and maintain privacy. Regularly clearing the DNS cache can be a useful troubleshooting step if you encounter issues with accessing websites.