网卡的奇怪问题，请教现要如何改？

szocean

[root@localhost etc]# ping 192.168.1.2
PING 192.168.1.2 (192.168.1.2) from 192.168.1.251 : 56(84) bytes of data.
64 bytes from 192.168.1.2: icmp_seq=1 ttl=64 time=0.676 ms

[root@localhost etc]# ping 202.96.128.68
PING 202.96.128.68 (202.96.128.6 from 192.168.1.123 : 56(84) bytes of data.
From 192.168.1.123 icmp_seq=1 Destination Host Unreachable

[root@localhost network-scripts]# cat ifcfg-eth0
DEVICE=eth1 (这里被改过，也可能是ifcfg-eth0和ifcfg-eth1文件名交换了)
ONBOOT=yes
BOOTPROTO=static
NETMASK=255.255.255.0
GATEWAY=192.168.1.1
IPADDR=192.168.1.123
TYPE=Ethernet

[root@localhost network-scripts]# cat ifcfg-eth1
DEVICE=eth0  (这里被改过)
BOOTPROTO=static
ONBOOT=yes
BROARDCAST=192.168.1.255
NETWORK=192.168.1.0
IPADDR=192.168.1.251
GATEWAY=192.168.1.1
NETMASK=255.255.255.0
TYPE=Ethernet
有二块网卡，现在网线只接在eth0上，IP是192.168.1.251，如何能让ping 出公网IP时会由eth0(192.168.1.251)出去呢？该如何改动？ 网线不动。