Centos7默认安装是没有开启配置网卡信息的，无法访问外网。
下边配置打开网络自动获取Ip地址
1.查看网卡信息
执行Ifconfig
eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet6 fe80::20c:29ff:fee8:8637 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:e8:86:37 txqueuelen 1000 (Ethernet)
RX packets 1121 bytes 98968 (96.6 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 179 bytes 25233 (24.6 KiB)
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 900 bytes 78372 (76.5 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 900 bytes 78372 (76.5 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
1.eno16777736代表网卡的名称，ether 00:0c:29:e8:86:37代表网卡的Mac地址
2.配置网卡开始网络连接
cd /etc/system/network-scripts/ vi ifcfg-eno16777736
HWADDR=00:0C:29:E8:86:37 TYPE=Ethernet BOOTPROTO=dhcp DEFROUTE=yes PEERDNS=yes PEERROUTES=yes IPV4_FAILURE_FATAL=no IPV6INIT=yes IPV6_AUTOCONF=yes IPV6_DEFROUTE=yes IPV6_PEERDNS=yes IPV6_PEERROUTES=yes IPV6_FAILURE_FATAL=no NAME=eno16777736 UUID=79d6c916-aab8-45e4-a163-37ae73393d26 ONBOOT=no
将ONBOOT= no改成ONBOOT=yes
3.重启网络
service network restart
4.再执行ifconfig
eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.159.128 netmask 255.255.255.0 broadcast 192.168.159.255
inet6 fe80::20c:29ff:fee8:8637 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:e8:86:37 txqueuelen 1000 (Ethernet)
RX packets 1699 bytes 140091 (136.8 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 333 bytes 42669 (41.6 KiB)
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 900 bytes 78372 (76.5 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 900 bytes 78372 (76.5 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
inet 192.168.159.128 代表IP地址
