1)设置默认路由(电信)
ip route replace default via 电信网关 dev eth1
2)对网通进行基于目的地址的策略路由
ip rule add to 网通路由表1 table cnc prio 100
ip rule add to 网通路由表2 table cnc prio 100
....
3)添加原路返回路由
ip route flush table ctc
ip route add default via 电信网关 dev eth1 src 电信IP table ctc
ip route add 192.168.0.0/24 dev eth0 scope link src 192.168.0.1 table ctc
ip rule add from 电信IP table ctc
ip route flush table cnc
ip route add default via 网通网关 dev eth2 src 网通IP table cnc
ip route add 192.168.0.0/24 dev eth0 scope link src 192.168.0.1 table ctc
ip rule add from 网通IP table cnc