Record a problem of raspberry pie DNS resolution failure

Recently, I found a raspberry pie that has been eating ash for many years 3b, It's a waste to be idle , How about a group Nextcloud Used as a network disk . As a result, domain name resolution always fails in the process of use , Raspberry pie is connected to the home router WiFi.

First, I try to modify vi /etc/resolv.conf file , add to nameserver 114.114.114.114 To solve , After modification, the problem of domain name resolution is indeed solved , But it was finally found that the raspberry pie would fail after restarting .

What's a good way to solve it ？

Actually, it needs to be modified resolved.conf file

sudo vi /etc/systemd/resolved.conf

Then delete DNS= The comment symbol on that line , Add DNS The address of the server , Here I am. 114.114.114.114 For example , After modification, it is ：

DNS=114.114.114.114

After the save , Restart again , Observe DNS Whether to take effect .

If you want to modify other DNS The server , Such as 8.8.8.8, Then modify it accordingly .