background:
When running the yum -y install net-tool package, an error is reported. Generally, if the network is connected to the external network, the yum resources on the network will be used for installation, but at this time, the error of Cent os 7 Error downloading packages is reported .
Finally, I found that it was a mistake in DNS. I actually wrote DNS0=8.8.8.8. The value is no problem. It does not start from 0, but from 1
solve:
Just change the corresponding DNS0 to DNS1, as shown in the figure
Note: 8.8.8.8 is an IP address, the IP address of the free DNS server provided by Google