刚装ubuntu,网关ping不通

[dangdanglove]

郁闷啊，装了ubuntu上不了网，校园网，网关ping不通

/etc/network/interfaces如下：
iface eth0 inet static
address 222.20.75.72
netmask 255.255.255.128
network 222.20.75.0
broadcast 222.20.75.127
gateway 222.20.75.126
谁能帮忙看看出了什么问题吗？