methods that have been tried so far
- modify / etc/resolvconf/resolv.conf.d/head
 - modify / etc/resolvconf/resolv.conf.d/base
 - modify / etc/resolvconf/resolv.conf.d/tail
 - modify / etc/network/interfaces
 - modify / etc/systemd/resolved.conf
 
but none of these methods work. My dsn is still reset after reboot. What should I do? I just came into contact with the linux system. I don"t understand.
