*刪除重新設定

1. 刪除網路連線 System ens3。

   [root@kvm8 ~]# nmcli connection delete System\ ens3 
   Connection 'System ens3' (f03ca672-c3f6-433a-b336-832566e18e76) successfully deleted.
   

2. 如果是用 ssh 連線，這時會斷線，必須回到虛擬機終端機重新「新增」網路連線。

   [root@kvm8 ~]# nmcli connection add \
   con-name ens3 ifname ens3 type ethernet \
   ipv4.addresses 192.168.122.8/24 \
   ipv4.gateway 192.168.122.1 \
   ipv4.dns 192.168.122.1 \
   ipv4.method manual
   Connection 'ens3' (a7b3ec85-0fa4-4bf3-b775-da87d43deacc) successfully added.
   

3. 查看網路連線，有 ens3 及 virbr0。

   [root@kvm8 ~]# nmcli connection 
   NAME                UUID                                  TYPE      DEVICE 
   ens3                bb2cf8be-1ea7-4ddd-8bc1-b5e9897aa72c  ethernet  ens3   
   virbr0              58932546-b263-4200-a998-3388a8653ae0  bridge    virbr0
   

4. 將網路連線 ens3 啟動。

   [root@kvm8 ~]# nmcli connection up ens3 
   Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/5)
   

5. 查看新增的網路連線設定 ens3 是否正確？是否生效？

   [root@kvm8 ~]# nmcli connection show ens3 | egrep -i ipv?4
   ipv4.method:                            manual
   ipv4.dns:                               192.168.122.1
   ipv4.dns-search:                        --
   ipv4.dns-options:                       ""
   ipv4.dns-priority:                      0
   ipv4.addresses:                         192.168.122.8/24
   ipv4.gateway:                           192.168.122.1
   ipv4.routes:                            --
   ipv4.route-metric:                      -1
   ipv4.route-table:                       0 (unspec)
   ipv4.ignore-auto-routes:                no
   ipv4.ignore-auto-dns:                   no
   ipv4.dhcp-client-id:                    --
   ipv4.dhcp-timeout:                      0 (default)
   ipv4.dhcp-send-hostname:                yes
   ipv4.dhcp-hostname:                     --
   ipv4.dhcp-fqdn:                         --
   ipv4.never-default:                     no
   ipv4.may-fail:                          yes
   ipv4.dad-timeout:                       -1 (default)
   IP4.ADDRESS[1]:                         192.168.122.8/24
   IP4.GATEWAY:                            192.168.122.1
   IP4.ROUTE[1]:                           dst = 192.168.122.0/24, nh = 0.0.0.0, mt = 100
   IP4.ROUTE[2]:                           dst = 0.0.0.0/0, nh = 192.168.122.1, mt = 100
   IP4.DNS[1]:                             192.168.122.1