开机，ip a 看一下系统默认使用那个网卡
1.编辑网络配置文件
vi /etc/network/interfaces
添加：
auto eth0
iface eth0 inet static
address 101.251.210.76
netmask 255.255.255.248 (29)
gateway 101.251.210.73
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2.设置dns
echo "nameserver 114.114.114.114" >>/etc/resolv.conf
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3.重启网卡
ifdown eth0
ifup eth0
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4.重启网络
/etc/init.d/networking restart
service networking restart