How to Change DNS in Linux
1. Access Terminal screen from Activities or press Ctrl +T to open the terminal. 2. In most of the Linux operating systems, the DNS servers that the system use for name resolution are defined in /etc/resolv.conf file. To make the changes, we need to open the resolv.conf file with an editor, such as nano.
https://support.strongvpn.com/hc/en-us/articles/360038982774-How-to-Change-DNS-in-Linux