How to prevent overwriting /etc/resolv.conf file after reboot

While deploying DNS Server, I came across a strange issue with the Resolv.conf file is automatically getting overwritten after a reboot of the server.

Solution:

Step1: Open NetworkManager.conf file using vim file editor

# vim /etc/NetworkManager/NetworkManager.conf

Step2: Add the following into the main section of NetworkManager.conf file and save the file

[main]

dns=none

Step3:  Restart the NetworkManager.service

#sudo systemctl restart NetworkManager.service

Step4: Add the DNS Servers in etc/resolv.conf file

#nameserver 1.1.1.1

Now /etc/resolv.conf file will have same DNS Server which is configured even after reboot.