auto eth0 iface eth0 inet static address 114.212.191.22 netmask 255.255.254.0 gateway 114.212.190.1 auto eth1 iface eth1 inet static address 192.168.1.100 netmask 255.255.255.0 gateway 192.168.1.1
上面是原来的网卡设置，每个网卡都设置了gateway，这样设置后重启网卡时会出现如下错误：
rtnetlink answers file exists fail to bring up eth1
去网上搜了一下，发现不能同时设置两个网关会导致路由表中出现两个默认路由，如果你有两个默认路由，在路由表中就会有两个0.0.0.0条目，系统不能处理这种情况，就会出现上面的错误
A gateway is an IP you send ALL traffic to. If you would have two, your routing table would have a double entry for dest 0.0.0.0 and the system can't handle this. The double route is what causes the RTNETLINK answer "File exists", meaning there is already a route for 0.0.0.0.
http://serverfault.com/questions/368349/can-only-bring-up-one-of-two-interfaces