操作系统：CentOS Linux release 7.8

实战任务：当配置resolv文件之后，如果重启了CentOS操作系统或者重启了网络服务，将在resolv文件中丁丁配置的将会丢失，下面将列出了解决此问题的操作步骤。

[root@localhost network-scripts]# vi /etc/resolv.conf 

# Generated by NetworkManager

nameserver 220.248.192.12

nameserver 220.248.192.13

nameserver 8.8.8.8

[root@localhost network-scripts]# cat /etc/resolv.conf 

# Generated by NetworkManager

nameserver 220.248.192.12

nameserver 220.248.192.13

nameserver 8.8.8.8

[root@localhost network-scripts]# ping 8.8.8.8

PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.

64 bytes from 8.8.8.8: icmp_seq=1 ttl=111 time=346 ms

64 bytes from 8.8.8.8: icmp_seq=2 ttl=111 time=349 ms

64 bytes from 8.8.8.8: icmp_seq=3 ttl=111 time=346 ms

[root@localhost network-scripts]# systemctl restart network

[root@localhost network-scripts]# cat /etc/resolv.conf 

# Generated by NetworkManager

nameserver 220.248.192.12

nameserver 220.248.192.13

[root@localhost network-scripts]# pwd

/etc/sysconfig/network-scripts

[root@localhost network-scripts]# vi ifcfg-eth0 

......

DNS1=220.248.192.12

DNS2=220.248.192.13

DNS3=8.8.8.8

......

[root@localhost network-scripts]#systemctl restart  network

[root@localhost ~]# cat  /etc/resolv.conf 

# Generated by NetworkManager

nameserver 220.248.192.12

nameserver 220.248.192.13

nameserver 8.8.8.8