在VMware 11里新装一个CentOS 7系统，开机发现没有网络，于是ifconfig一下发现：
eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
ether 00:0c:29:2b:c0:1e txqueuelen 1000 (Ethernet)
RX packets 1 bytes 138 (138.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 0 (Local Loopback)
RX packets 386 bytes 33512 (32.7 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 386 bytes 33512 (32.7 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
发现是网卡没有启动。
于是service network restart 显示：
Restarting network (via systemctl): [ OK ]
再次查看网卡"ifconfig"，还是老样子。
于是"ifup eno16777736"手动重启网卡，提示：
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/0) 启动成功
再次查看网卡"ifconfig"，正常。