Flush DNS in Linux - Shell/Bash

Flushing DNS in Linux is a common task for developers and system administrators. Whether you need to test your website for DNS changes or resolve network issues, flushing DNS can help.

In this article, we will cover the following topics:

• What is DNS?
• Why do you need to flush DNS?
• How to flush DNS in Linux using Shell/Bash commands

What is DNS?

DNS stands for Domain Name System. It is a hierarchical and decentralized naming system for computers, services, or any resource connected to the internet or a private network. DNS translates domain names into IP addresses, making it easier for users to access websites and other resources.

Why do you need to flush DNS?

There are several reasons why you may need to flush DNS in Linux:

• You made changes to your DNS settings and want to test your website
• You want to clear your DNS cache to resolve network issues
• You want to troubleshoot DNS-related problems
• You want to prevent DNS spoofing attacks

How to flush DNS in Linux using Shell/Bash commands

Here are the Shell/Bash commands you can use to flush DNS in Linux:

sudo systemd-resolve --flush-caches
sudo /etc/init.d/nscd restart
sudo service networking restart

Let's take a closer look at each command:

sudo systemd-resolve --flush-caches

This command flushes the DNS cache maintained by the systemd-resolved service. The sudo command is necessary to run the command with root privileges.

sudo /etc/init.d/nscd restart

This command restarts the Name Service Cache Daemon (NSCD) service, which is responsible for caching name service lookups. The sudo command is necessary to run the command with root privileges.

sudo service networking restart

This command restarts the networking service, which is responsible for managing network interfaces, IP addresses, and other network-related settings. The sudo command is necessary to run the command with root privileges.

It's worth noting that the commands may vary slightly depending on your Linux distribution and version. Some distributions may use systemctl instead of service to manage services, for example.

Conclusion

Flushing DNS in Linux is a simple but important task that can help you resolve network issues and test your website's DNS settings. By using the Shell/Bash commands we covered in this article, you can quickly flush DNS cache and troubleshoot DNS-related problems.