eht0接电信网线 ,eth1接网通网线
$if_tel=电信IP $gw_tel=电信网关
$if_cnc=网通IP $gw_cnc=网通网关
Linux
ip route add default via $gw_tel dev eth0 src $if_tel table 100
ip route add default via $gw_cnc dev eth1 src $if_cnc table 200
ip rule add from $if_tel table 100
ip rule add from $if_cnc table 200
FreeBSD
pass out quick route-to ( 电信网卡 电信网关IP ) from 电信IP to any
pass out quick route-to ( 网通网卡 网通网关IP ) from 网通IP to any