Follow the below mentioned steps to clear the local DNS cache in Linux Server:
1. Open your terminal to use the command line.
2. Log in as root user using the su command:
Password: (type your root user password here)
3. Restart the name service cache daemon (NSCD):
root@host: /etc/init.d/nscd restart
Note: The Name Service Cache Daemon (NSCD) might not be installed by default on your Linux. You must be able to install it by using the package manager of your distribution – yum for RedHat-based distribution such as Fedora, CentOS and apt-get for Debian-based distribution such as Ubuntu, Kubuntu.
More about Linux Server: How to Reboot a Linux Server using Command Line