修改網卡設定

1. 不必刪除設定，直接使用 modify 選項變更設定。設定 ipv4 位址 192.168.122.8、遮罩 255.255.255.0、GATEWAY 192.168.122.1 及 DNS 192.168.122.1，最後一定要設定 ipv4.method 為 manual，將網路連線設定為手動，也就是自行設定 IP，不是由 DHCP 自動取得，否則原 DHCP 取得的 IP 還會存在。

   [root@kvm8 ~]# nmcli connection modify System\ ens3 \
   ipv4.addresses 192.168.122.8/24 \
   ipv4.gateway 192.168.122.1 \
   ipv4.dns 192.168.122.1 \
   ipv4.method manual
   

2. 將網路連線 System ens3 啟動。

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

3. 查看網卡設定，看手動設定是否正確？

   [root@kvm8 ~]# nmcli connection show System\ 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