vim /etc/network/interfaces

# 加入
dns-nameservers 8.8.8.8 8.8.4.4

vim /etc/dhcp/dhclient.conf

# 写死
supersede domain-name-servers 8.8.8.8;

systemctl restart networking

查看dns是否正确 cat /etc/reslov.conf

nameserver 8.8.8.8
nameserver 8.8.4.4